阅读说明：本技术 用于在鼻炎的治疗中定位血管的系统和方法 (System and method for locating blood vessels in the treatment of rhinitis ) 是由 B·费伊 B·林 W·J·福克斯 M·萨阿达特 V·萨阿达特 于 2018-04-30 设计创作，主要内容包括：本文公开用于治疗和监测诸如鼻炎的病症的设备和方法。该技术利用超声扫描以识别目标治疗位点,并监测经受治疗的患者的治疗。治疗可以是鼻神经(例如用于治疗诸如鼻炎的鼻病症的PNN)的消融治疗。超声扫描用超声探针或组合的超声和消融探针在鼻腔内进行,并且可使用多普勒、A模式、B模式、M模式或其他超声和非超声方式来检测和监测目标治疗位点。(Disclosed herein are devices and methods for treating and monitoring conditions such as rhinitis. The technique utilizes ultrasound scanning to identify a target treatment site and monitor the treatment of a patient undergoing treatment. The treatment may be an ablative treatment of nasal nerves (e.g., PNN for treating nasal conditions such as rhinitis). Ultrasound scanning is performed within the nasal cavity with an ultrasound probe or combined ultrasound and ablation probe, and the target treatment site can be detected and monitored using doppler, a-mode, B-mode, M-mode, or other ultrasound and non-ultrasound modalities.)

1. A method for treating rhinitis in a patient, the method comprising:

advancing a surgical probe into a nasal cavity of a patient, the surgical probe including an elongate probe shaft having a proximal end and a distal end, a handle coupled to the proximal end, an ultrasound transducer coupled to the probe shaft, and a cryoablation element coupled to the probe shaft;

determining a location of a target treatment site within the nasal cavity with the ultrasound transducer;

positioning the cryoablation element at the target treatment site location; and

cryoablating the target treatment site so as to ablate the at least one nasal nerve to reduce the at least one symptom of rhinitis.

2. The method of claim 1, wherein determining the location of the target treatment site comprises detecting a relative thickness of mucosal tissue in the nasal cavity with the ultrasound transducer to identify an anatomical landmark associated with the location of the target treatment site.

3. The method of claim 1, wherein determining the location of the target treatment site comprises detecting a relative thickness of a palatine or sphenoid bone in the nasal cavity with the ultrasound transducer to identify an anatomical landmark associated with the location of the target treatment site.

4. The method of claim 1, wherein determining the location of the target treatment site comprises detecting a relative boundary or transition between two bones in the nasal cavity or between a bone and cartilage in the nasal cavity with the ultrasound transducer to identify an anatomical landmark associated with the location of the target treatment site.

5. The method of claim 4, wherein the transition comprises 0.5-1mm of cartilage adjacent to 1-3mm of bone used to identify the perpendicular term of the palatine bone.

6. The method of claim 1, wherein the surgical probe further comprises a second ultrasonic transducer coupled to the probe shaft,

wherein the ultrasound transducer is coupled to the probe shaft relative to a distal end of the probe shaft and a distal side of the cryoablation element, and wherein the second ultrasound transducer is coupled to the probe shaft relative to a proximal end of the probe shaft and a proximal side of the cryoablation element, and

wherein determining the location of the target treatment site comprises detecting a tissue property with both the ultrasound transducer and the second ultrasound transducer.

7. The method of claim 6, wherein detecting tissue properties with the ultrasound transducer and the second ultrasound transducer to determine the location of the target treatment site comprises identifying a relative mucosal tissue thickness indicative of the cryoablation element being positioned proximate to the target treatment site.

8. The method of claim 6, wherein detecting tissue properties with the ultrasound transducer and the second ultrasound transducer to determine the location of the target treatment site comprises identifying a relative bone thickness indicating a location at which the cryoablation element is positioned proximate the target treatment site.

9. The method of claim 8, wherein the relative bone thickness indicates that the ultrasound transducer detected a sphenoid bone and the second ultrasound transducer detected a palatine bone.

10. The method of claim 1, wherein the cryoablation element and the ultrasound transducer are coupled to the probe shaft at a predetermined distance relative to each other,

wherein the predetermined distance corresponds to a distance between an anatomical feature detectable with the ultrasound transducer and at least one nasal nerve,

wherein determining the location of the target treatment site comprises locating the anatomical feature with the ultrasound transducer, an

Wherein cryoablating the target treatment site comprises ablating the at least one nasal nerve when the ultrasound transducer detects a signal indicative of the ultrasound transducer being proximate to the anatomical feature.

11. The method of claim 10, wherein the anatomical feature is a blood vessel.

12. The method of claim 1, wherein advancing the surgical probe into the nasal cavity comprises determining that the surgical probe is being advanced through a middle meatus by detecting a middle turbinate in the nasal cavity with the ultrasound transducer.

13. The method of claim 1, wherein the probe shaft comprises an articulation joint configured to facilitate articulation of the ultrasound transducer relative to the cryoablation element, and

wherein determining the location of the target treatment site with the ultrasound transducer comprises articulating the ultrasound transducer with the articulation joint to scan a tissue region within the nasal cavity.

14. The method of claim 1, wherein the surgical probe further comprises a light emitting element coupled to the probe shaft, and wherein the light emitting element emits a visual indication within the nasal cavity when the position of the target treatment site is determined.

15. The method of claim 1, wherein the surgical probe further comprises a tactile feedback element coupled to the handle, and wherein the tactile feedback element emits a tactile indication when the position of the target treatment site is determined.

16. The method of claim 1, wherein the cryoablation element comprises an expandable structure, and

wherein cryoablating the target treatment site comprises expanding the expandable structure by vaporization of a cryogenic fluid within the expandable structure.

17. The method of claim 1, further comprising monitoring a size of an iceball formed upon cryoablation of the target treatment site with the ultrasound transducer or a second ultrasound transducer coupled to the probe shaft,

wherein the ultrasonic transducer or the second ultrasonic transducer emits an ultrasonic beam at an angle relative to a longitudinal axis of the probe shaft so as to traverse tissue in the nasal cavity where the iceball is formed.

18. The method of claim 17, further comprising terminating cryoablation when the ice ball size reaches a predetermined size range.

19. The method of claim 1, wherein the cryoablation element is slidably coupled to the probe shaft, wherein after determining the location of the target treatment site, advancing the cryoablation element into the nasal cavity by sliding the cryoablation element along the shaft toward a distal end of the surgical probe shaft to the target treatment site.

20. A method for treating rhinitis in a patient, the method comprising:

advancing a surgical probe into a nasal cavity of a patient, the surgical probe including an elongate probe shaft having a proximal end and a distal end, a handle coupled to the proximal end, and an ultrasonic transducer coupled to the distal end of the probe shaft;

detecting anatomical features within the nasal cavity with the ultrasound transducer to determine a location of a target treatment site;

advancing a cryoablation element slidably coupled to the probe shaft toward the distal end to the determined target treatment site location when the ultrasound transducer is positioned proximate the detected anatomical feature; and

cryoablating the target treatment site while the ultrasound transducer is positioned proximate the detected anatomical feature so as to ablate at least one nasal nerve to reduce at least one symptom of rhinitis.

21. The method of claim 20, wherein the anatomical feature is a blood vessel, and

wherein detecting the location of the anatomical feature comprises detecting blood flow in the blood vessel.

22. The method of claim 21, wherein the blood vessel is a sphenopalatine artery or vein.

23. The method of claim 20, wherein the cryoablation element comprises an expandable structure, and

wherein cryoablating the target treatment site comprises expanding the expandable structure by vaporization of a cryogenic fluid within the expandable structure.

24. The method of claim 23, wherein the expandable structure has an inner lumen, and

wherein advancing the cryoablation element comprises sliding the probe shaft through the lumen.

25. The method of claim 20, wherein a distance between the detected anatomical feature and the target treatment site location corresponds to a distance between a sphenopalatine artery or vein and the at least one nasal nerve.

26. A method of assessing a treatment procedure within a nasal cavity of a patient based on tissue characteristics measured with ultrasound, the method comprising:

evaluating a pre-treatment tissue characteristic with a first ultrasound scan of the nasal cavity;

performing a treatment procedure within the nasal cavity;

evaluating post-treatment tissue characteristics with a second ultrasound scan of the nasal cavity; and

evaluating a change between the pre-treatment tissue characteristic and the post-treatment tissue characteristic to evaluate an effectiveness of the treatment procedure.

27. The method of claim 26, wherein performing the treatment procedure comprises cryoablating at least one nasal nerve to reduce at least one symptom of rhinitis.

28. The method of claim 27, wherein the pre-treatment tissue characteristic and the post-treatment characteristic comprise mucosal tissue thickness, edema, or fluid content.

29. The method of claim 28, wherein evaluating the change between the pre-treatment tissue characteristic and the post-treatment tissue characteristic further comprises considering a contact force applied by an ultrasound transducer to a nasal cavity wall or an angle of incidence of an ultrasound beam.

30. The method of claim 28, wherein the first and second ultrasound scans comprise echogenicity measurements, elastography measurements, or elastography measurements of the mucosal tissue.

31. The method of claim 26, further comprising re-treating the nasal cavity in response to an assessment of a change between a pre-treatment tissue characteristic and the post-treatment tissue characteristic.

32. The method of claim 26, wherein performing the treatment procedure comprises mechanically, chemically, electrically, or thermally treating the nasal cavity.

33. A surgical probe for treating rhinitis in a patient, comprising:

an elongate probe shaft having a proximal end and a distal end;

a handle coupled to the proximal end;

an ultrasonic transducer coupled to the probe shaft; and

a cryoablation element coupled to the probe shaft;

wherein the ultrasound transducer is configured to determine a location of a target treatment site within a nasal cavity of the patient, and

wherein the cryoablation element is configured to be positioned at the target treatment site location to cryoablate the target treatment site in order to ablate the at least one nasal nerve to reduce at least one symptom of rhinitis.

34. The surgical probe according to claim 33, wherein the ultrasonic transducer is configured to detect relative thickness of mucosal tissue in the nasal cavity to identify anatomical landmarks associated with the location of the target treatment site.

35. The surgical probe of any of claims 33 or 34, wherein the ultrasound transducer is configured to determine the location of the target treatment site by detecting a relative thickness of a palatine or sphenoid bone in the nasal cavity to identify an anatomical landmark correlated to the location of the target treatment site.

36. The surgical probe of any one of claims 33-35, wherein the ultrasound transducer is configured to determine the location of the target treatment site by detecting a relative boundary or transition between two bones in the nasal cavity or between a bone and cartilage in the nasal cavity to identify an anatomical landmark that correlates with the location of the target treatment site.

37. The surgical probe of claim 36, wherein the transition comprises 0.5-1mm of cartilage adjacent to 1-3mm of bone for identifying the perpendicular term of the palatine bone.

38. The surgical probe according to any one of claims 33-37, further comprising a second ultrasonic transducer coupled to the probe shaft,

wherein the ultrasound transducer is coupled to the probe shaft relative to a distal end of the probe shaft and a distal side of the cryoablation element, and wherein the second ultrasound transducer is coupled to the probe shaft relative to a proximal end of the probe shaft and a proximal side of the cryoablation element, and

wherein the ultrasound transducer and the second ultrasound transducer are configured to determine the location of the target treatment site by detecting tissue properties with both.

39. The surgical probe of claim 38, wherein the ultrasonic transducer and the second ultrasonic transducer are configured to detect tissue properties to determine the location of the target treatment site by identifying a relative mucosal tissue thickness indicative of the cryoablation element being positioned proximate the location of the target treatment site.

40. The surgical probe of claim 38, wherein the ultrasound transducer and the second ultrasound transducer are configured to detect tissue properties to determine the location of the target treatment site by identifying a relative bone thickness indicating a location at which the cryoablation element is positioned proximate the target treatment site.

41. The surgical probe of claim 40, wherein the relative bone thickness indicates that the ultrasound transducer detected a sphenoid bone and the second ultrasound transducer detected a palatine bone.

42. The surgical probe according to any of claims 33-37, wherein the cryoablation element and the ultrasound transducer are coupled to the probe shaft at a predetermined distance relative to each other,

wherein the predetermined distance corresponds to a distance between an anatomical feature detectable with the ultrasound transducer and the at least one nasal nerve,

wherein the ultrasound transducer is configured to determine a location of the target treatment site by locating the anatomical feature, and

wherein the cryoablation element is configured to cryoablate the target treatment site by ablating the at least one nasal nerve when the ultrasound transducer detects a signal indicative of the ultrasound transducer being proximate to the anatomical feature.

43. The surgical probe according to claim 42, wherein the anatomical feature is a blood vessel.

44. The surgical probe according to any one of claims 33-38 and 42, wherein the ultrasound transducer is configured to determine that the surgical probe is being advanced through the middle meatus by detecting the middle turbinate in the nasal cavity.

45. The surgical probe of any of claims 33-38, 42 and 44, wherein the probe shaft comprises an articulation joint configured to facilitate articulation of the ultrasound transducer relative to the cryoablation element, and

wherein the ultrasound transducer is configured to determine the location of the target treatment site by articulating the ultrasound transducer with the articulation joint to scan a tissue region within the nasal cavity.

46. The surgical probe according to any of claims 33-38, 42, 44 and 45, further comprising a light emitting element coupled to the probe shaft and configured to emit a visual indication within the nasal cavity when the position of the target treatment site is determined.

47. The surgical probe of any of claims 33-38, 42, 44, 45, and 46, further comprising a tactile feedback element coupled to the handle and configured to issue a tactile indication when the location of the target treatment site is determined.

48. The surgical probe of any of claims 33-38, 42, 44, 45, 46 and 47, wherein the cryoablation element comprises an expandable structure and is configured to be expanded by vaporization of cryogenic fluid within the expandable structure to cryoablate the target treatment.

49. The surgical probe of any of claims 33-38, 42, 44, 45, 46, 47 and 48, wherein the ultrasound transducer is configured to monitor the size of an iceball formed upon cryoablation of the target treatment site, and

wherein the ultrasound transducer is configured to emit an ultrasound beam at an angle relative to a longitudinal axis of the probe shaft so as to traverse tissue in the nasal cavity where the iceball is formed.

50. The surgical probe according to claim 49, wherein the cryoablation element is configured to terminate cryoablation when the size of the iceball reaches a predetermined size range.

51. The surgical probe of any of claims 33-38, 42, 44, 45, 46, 47, 48 and 49, wherein the cryoablation element is slidably coupled to the probe shaft,

wherein the cryoablation element is configured to be advanced into the nasal cavity by sliding the cryoablation element along the shaft toward a distal end of the surgical probe shaft to the target treatment site after determining the location of the target treatment site with the ultrasound transducer.

52. A surgical probe for treating rhinitis in a patient, comprising:

an elongate probe shaft having a proximal end and a distal end;

a handle coupled to the proximal end;

an ultrasonic transducer coupled to a distal end of the probe shaft; and

a cryoablation element slidably coupled to the probe shaft;

wherein the ultrasound transducer is configured to detect anatomical features within the nasal cavity in order to determine a location of a target treatment site, and

wherein the cryoablation element is configured to advance toward the distal end to the determined target treatment site location when the ultrasound transducer is positioned proximate the detected anatomical feature and cryoablate the target treatment site when the ultrasound transducer is positioned proximate the detected anatomical feature so as to ablate at least one nasal nerve to reduce at least one symptom of rhinitis.

53. The surgical probe according to claim 52, wherein the anatomical feature is a blood vessel, and

wherein the ultrasound transducer is configured to detect a location of the anatomical feature by detecting blood flow in the blood vessel.

54. The surgical probe of claim 53, wherein the blood vessel is a sphenopalatine artery or vein.

55. The surgical probe of any of claims 52-54, wherein the cryoablation element comprises an expandable structure, and

wherein the cryoablation element is configured to cryoablate the target treatment site by expanding the expandable structure through vaporization of a cryogenic fluid within the expandable structure.

56. The surgical probe according to claim 55, wherein the expandable structure has an inner lumen, and

wherein the cryoablation element is configured to be advanced by sliding the probe shaft through the lumen.

57. The surgical probe of any of claims 52-56, wherein a distance between the detected anatomical feature and the target treatment site location corresponds to a distance between a sphenopalatine artery or vein and the at least one nasal nerve.

Technical Field

The present invention relates to systems, devices and methods for identifying and monitoring treatment sites for ablating tissue regions. More particularly, the present invention relates to locating a treatment site in the nasal cavity for ablation for treating a nasal condition such as rhinitis while inhibiting or reducing any side-by-side vascular damage (e.g., arterial bleeding).

Background

Rhinitis is defined as inflammation of the membrane lining the nose and is characterized by nasal symptoms including itching, sneezing, anterior nasal drip (rhinorrhea), posterior nasal drip (retronasal drip), and/or nasal congestion. Chronic rhinitis affects tens of millions of people in the united states and is the primary reason patients seek medical care. Medical treatment has proven to have limited effectiveness in patients with chronic rhinitis and requires daily medication or cumbersome allergy therapy, and up to 20% of patients may be refractory.

Selectively interrupting the Posterior Nasal Nerves (PNN) of patients with chronic rhinitis can improve their symptoms while avoiding morbidity associated with winged canal denervation. In particular, selective interruption of PNN interrupts the innervation of somatic afferents to the nasal mucosa and may reduce hypersensitivity and axonal reflex of the nasal mucosa. While ablation of PNN is a minimally invasive procedure with fewer complications and side effects than previous surgical methods for treating rhinitis, complications may exist if large blood vessels are damaged during ablation.

As shown in fig. 1 and 2, the PNN is generally along the sphenopalatine artery (SPA). In some patient anatomies, the SPA may be co-located with the PNN. As a result, during ablation of the PNN, inadvertent collateral damage to the SPA may occur, which may result in excessive bleeding or other damage to the patient. In some cases, excessive epistaxis may require subsequent surgical treatment or intervention to repair the damaged SPA. Accordingly, there is a need for improved systems, devices, and methods that address some of these therapeutic challenges.

Summary of The Invention

The present technology relates to systems, devices, and methods for using ultrasound to identify a target treatment site and monitor treatment of a patient undergoing ablation treatment of nasal nerves (e.g., PNN) for treatment of nasal conditions such as rhinitis. Such systems, devices, and methods provide ablation of PNN while inhibiting and/or reducing unintended side-vessel damage (e.g., bleeding of SPA or branches associated therewith). The present techniques may also be used to treat nasal valve collapse. The present technology may also be used to treat retronasal drip and other related conditions, as disclosed in U.S. patent 9,801,752, which is incorporated herein by reference in its entirety for all purposes. The present technology may also be used for neuromodulation and other related therapies, as disclosed in U.S. published application 2016/0331459a1, which is incorporated herein by reference in its entirety for all purposes.

Brief Description of Drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. In the drawings, like reference numbers indicate similar or functionally similar elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

Figure 1 shows the anatomy of the nerve in the nasal canal.

Figure 2 shows the anatomy of blood vessels in the nasal tube.

Figures 3-5 show diagrams of detecting doppler signals.

Fig. 6 shows an a-mode scan, with the y-axis representing reflected signal strength and the x-axis representing the time between signal emission and signal detection times.

Fig. 7A shows a-mode and B-mode scans showing tissue interfaces in the back/spine and their associated ultrasound echoes.

Fig. 7B illustrates an a-mode scan showing tissue interfaces in the eye and their associated ultrasound echoes.

Fig. 8 shows an embodiment of an ultrasound probe.

Figures 9A-C illustrate an embodiment of an ultrasound probe.

Figures 10A-B illustrate a method of locating an SPA using ultrasound and doppler signals.

Figure 11A illustrates an embodiment of an ultrasound probe having multiple ultrasound units.

FIGS. 11B-C illustrate the use of the probe of FIG. 11A to locate the SPA.

FIGS. 12A-F illustrate the use of the probe of FIG. 11A to locate the SPA.

Fig. 13A and 13B illustrate an embodiment of an ultrasound probe with a slidable ultrasound transducer.

Fig. 14 shows an embodiment of an ultrasound probe with a visual indicator.

Fig. 15A and 15B illustrate an embodiment of an ultrasound probe having a plurality of visual indicators.

Fig. 16A and 16B illustrate an embodiment that provides a visual indication of ultrasound signal intensity.

Fig. 17A-D illustrate an embodiment of an integrated probe.

Fig. 18 shows an embodiment of an integrated probe.

Fig. 19A-C illustrate an embodiment of an integrated probe.

Fig. 20-22 illustrate an embodiment of an integrated probe.

Fig. 23A-D illustrate an embodiment of an integrated probe having a fixed distance between the ultrasound transducer and the cryoablation element.

Figures 24A-B illustrate an embodiment of an integrated probe for detecting bone thickness.

Fig. 25A-C illustrate an embodiment of an integrated probe.

Fig. 26A-D illustrate an embodiment of an integrated probe having a slidably coupled cryoablation element.

Fig. 27A-C show an embodiment of an integrated probe for monitoring ice ball formation.

Fig. 28A and 28B illustrate an ultrasound transducer mounted on a single axis joint to facilitate vertical alignment with a tissue surface.

Fig. 28C and 28D show the ultrasound transducer mounted on a ball joint to facilitate vertical alignment with the tissue surface.

Fig. 29 shows a self-aligning ultrasound transducer.

Fig. 30 shows an embodiment of a combined ablation and sensing probe with an acoustically coupled balloon.

Fig. 31A-C illustrate an embodiment utilizing a turbinate to guide placement of an ablation probe in a tissue region.

Fig. 32A-C illustrate an embodiment using mechanical sensors to guide positioning.

Fig. 33-36 illustrate an embodiment of an optical sensing system.

Detailed Description

In the following description, various embodiments of the present technology will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that the present technology may be practiced without these specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the described embodiments.

In an embodiment, an ultrasound transducer may be used to detect a doppler signal indicative of the presence of a blood vessel. For example, in an embodiment, the sphenopalatine artery (SPA) may be located. Further, in embodiments, other vessels may be located, for example, branches of the SPA or the pre-ethmoid artery. The located vessel may be used to determine a target ablation site to treat a nerve that may be located based on the location of the vessel, and the location of the vessel may also be used to avoid damage to the located vessel. For example, in embodiments, the SPA can be located and the location of the SPA can be used to determine a target ablation site for treating PNN while avoiding ablation and damage to the SPA. In embodiments, the located vessel can then be used to determine a target ablation site that can selectively damage the SPA or other vessel.

Fig. 3 and 4 illustrate a method of using multiple pulses transmitted through a fluid containing moving particles, and illustrate the detected reflections of the pulses as time-shifted echoes. The time-shift approach is a mechanism by which ultrasound and other imaging modalities can be used to estimate tissue motion and/or velocity. Other mechanisms include frequency shift analysis and phase shift estimators. As used herein, the terms "measuring doppler shift," "measuring doppler signal," or similar language, refer to the use of any of these described methods or related methods for estimating tissue motion.

Fig. 5 shows the arrangement of the transducer and the blood vessel, and provides equations that can be used to determine blood flow velocity. The equation shown is based on acoustic waves, such as ultrasound, however, doppler shifts can also be observed with other forms of energy such as visible light, IR, or other acoustic or electromagnetic waves to detect blood flow. These forms of energy may be emitted from a transmitter and the reflected signal may then be received by a receiver and used to detect a region of the body having blood flow in the tissue. Other types of tissue motion or movement may be determined using similar methods. The sensing region where energy is transmitted and received may be small and by passing a sensor for detecting doppler shift around a larger tissue region, as will be discussed in more detail below, a particular tissue region including blood flow and thus blood vessels may be determined.

In embodiments, the ultrasound probe may also be used to detect the location of the SPA using other characteristics of the vasculature not related to blood flow, including ultrasound reflections and velocity changes through the vessel wall and the intraluminal space compared to the surrounding tissue.

In embodiments, as discussed in more detail below, a blood vessel (e.g., SPA) may be located using an ultrasound probe. The determined position can then be used to inform the operator to determine the target treatment site. Ablation therapy at the target treatment site can then be performed to provide treatment for rhinitis symptoms while avoiding the level of damage to the SPA and its branches that may require repair. As will be discussed in more detail below, in embodiments, the system may include an ultrasound probe and an ablation probe, for example, as disclosed in u.s.14/503,060, which is incorporated herein by reference.

In addition to using ultrasound signals to detect blood flow by detecting doppler shifts, ultrasound signals may also be used to detect anatomical features such as tissue thickness including bone and mucosal thickness, and transitions between different types or thicknesses of tissue. The detection may be performed, for example, using a-mode or B-mode ultrasound. The detection of the anatomical features may be used to determine the location of a target treatment site for ablation. For example, the location of the bony prominence and the area of varying mucosal thickness may correspond to the location of the target nerve in the nasal cavity. Identifying anatomical features can be used to determine the location of a target treatment site to ablate a target nerve.

A-mode (amplitude mode) ultrasound is a mode in which an ultrasound pulse is transmitted into the tissue and the reflected component of the signal is measured over time. Tissue acoustic impedance is a function of the stiffness of the tissue and the speed of sound in the tissue. The propagating ultrasonic wave is reflected at the interface between tissues having different acoustic impedances, and the degree of signal reflection increases as the difference increases. Small differences produce small echoes and large differences produce larger echoes.

The time between the transmission of the ultrasound signal and the detection of the reflected signal is a function of the speed of sound in the tissue and the depth at which the signal is reflected. During an a-mode scan, which records the amplitude of received echoes from transmitted ultrasound pulses over a period of time, signals reflected from deeper tissue will appear in the recording later than signals reflected more shallowly. The table below shows the speed of sound in different common tissues.

In order to convert the echo delay (time elapsed between transmission of an ultrasound pulse and detection of a corresponding echo) into depth, an average speed of sound may be used. In soft tissue, the speed of sound is generally considered constant and is considered to be a value of 1540 m/s.

Depth (m) ═ average speed of sound (m/s) × 1/2 × delay(s)

In the above relationship, the factor (1/2) is due to the fact that the echo delay is made up of the round trip travel time of the ultrasonic pulse (i.e., the time it takes the ultrasonic wave to reach the depth of the reflecting surface plus the time it takes the wave to travel from the point of reflection back to the transducer).

Tissue type	Speed of sound (m/s)
		Skin(s)	1600
Fat	1400
		Muscle	1600
Bone	3500

TABLE 1 speed of sound in common tissues

The table below shows the percentage of incident signal reflected at the boundary between different tissues.

Table 2: percent reflection of ultrasound at the boundary: from Aldrich, Crit Care Med, Volume 35(5) Suppl. May 2007.S131-S137

Fig. 6 and 7A-B illustrate examples of a-mode scanning. In fig. 6, the y-axis represents the reflected signal strength and the x-axis represents the time between signal emission and signal detection times. In fig. 6, peaks a and B represent interfaces between tissues of significantly different acoustic impedances. Spike a represents a shallower interface than spike B, and wherein the difference in acoustic impedance between the tissues is greater than spike B. The depth of the tissue interface represented by the spikes a and B can be estimated by multiplying the average speed of sound in the tissue by 1/2 of the delay between the signal emission and the detection of the correlated reflection.

In embodiments, a-mode scanning may be used to determine the depth of mucosal tissue, the depth of bone, the thickness of bone in the nasal cavity, and the transition between different tissue thicknesses and densities. In an embodiment, detectable spikes on a-mode traces corresponding to interfaces of tissues with significantly different acoustic impedances can be used to estimate shallow and deep boundaries of mucosal tissue. From these estimates, thickness measurements can be made. For example, in embodiments, a large a-mode spike corresponding to the interface of the coupling balloon and the shallow mucosal wall may be detected, and a second large a-mode spike corresponding to the interface of the deep mucosal tissue and the bone tissue may be generated. The distance between these peaks, calculated using the time delay and the estimated ultrasound propagation velocity, allows the thickness of the mucosal tissue to be calculated. In embodiments, mucosal tissue thickness may not be measured directly, and bony landmarks may instead be identified. In embodiments where bony landmarks are identified, a-mode ultrasound can be used to locate the treatment region by determining where bony landmarks (including regions of varying bone thickness) are present.

Fig. 7A shows example a-mode and B-mode scans showing tissue interfaces in the back/spine and their associated ultrasound echoes. Fig. 7B illustrates an a-mode scan showing tissue interfaces in the eye and their associated ultrasound echoes. A-mode and B-mode scans within the nasal cavity may show similar spikes due to interfaces of various tissue types.

In embodiments, ultrasound techniques such as a-mode and B-mode scanning can be used to locate bony landmarks such as foramina, and more particularly the sphenopalatine foramen. The sphenopalatine foramen is the opening in the bone through which the SPA and the posterior nasal nerve travel. For example, as described above, the a-mode signal may be used to display thickness and/or reflection amplitude measurements of the palatine and sphenoid bones surrounding the hole, and may display different signal characteristics when the ultrasound beam is aimed at the hole. For example, there may be reduced acoustic shadowing and/or reflection associated with the aperture.

In embodiments, ultrasound can be used to detect differences between cartilage and bone. The impedance difference between cartilage and mucosal tissue is smaller than the impedance difference between bone and mucosal tissue, and a-mode measurement of echoes from the underlying cartilage region results in a lower amplitude signal than measurements in the underlying bone region. These differences in signal amplitude can be used to distinguish between regions or to locate transitions between regions.

In embodiments, a-mode ultrasound may be used to measure mucosal tissue thickness prior to treatment. These measurements can be used to guide the operator in administering the decongestant. The tissue thickness information may also be used prior to treatment to determine the treatment dosage, including ablation member target temperature and treatment duration, and in a multi-cycle treatment model, cycle number or treatment time. For example, thicker mucosal tissue may require longer treatment times, lower temperatures, and/or more treatment cycles than thinner mucosal tissue. The treatment time can be tailored using tissue thickness and tissue penetration rate.

Ultrasound measurements may be used during treatment to detect changes in tissue properties associated with freezing, or may be used after treatment to assess any tissue changes due to ablation therapy. For example, during and after treatment, the ultrasound signal may detect changes in tissue acoustic impedance (as indicated by changes in the echogenicity of the target region).

Ultrasound measurements may be taken at the treatment site prior to treatment to measure baseline characteristics of the tissue to be treated. These characteristics may include tissue thickness, echogenicity, elasticity, local blood flow, or degree or type of movement (physiological or otherwise) measured.

In an embodiment, gain compensation may be used to compensate for a known loss in ultrasound signal intensity that may be present in echoes produced by deeper tissue regions. As an ultrasound wave propagates through tissue, its intensity decreases exponentially with depth due to both scattering and absorption. This loss of intensity is proportional to the ultrasound frequency used and depends on the nature of the tissue being interrogated. The attenuation coefficient is typically specified in units of dB/cm/MHz, where dB refers to decibels. In soft tissue, the attenuation coefficient is typically in the range of 0.5 to 1.0, but it is lower in blood (-0.2) and much higher in bone (-10 +). Gain compensation can be performed to compensate by estimating the expected loss of signal strength over the depth of interest and mathematically adjusting the measured signal. In embodiments, this may facilitate comparison of tissue interfaces, for example by allowing nearly identical tissue interfaces to produce similar a-mode amplitudes, even if these interfaces occur at depths that are significantly different from the transducer.

Using techniques similar to those described above, a-mode ultrasound can be used to measure bone thickness, differentiate cartilage and bone, or differentiate bones of different thicknesses. A-mode ultrasound can also be used to identify transitions between cartilage and bone or between bones of different thicknesses.

The sphenopalatine artery and the sphenopalatine foramen through which the posterior nasal nerves enter the nasal cavity are higher than the chimney of the maxillary sinus at the intersection of the palatine bone and the much thicker sphenoid bone. A-mode ultrasound can detect differences in mucosal thickness in the areas near these bones and fontanels, with thicker coverage on the palatine bone than the sphenoid mucosal tissue. The interface between these bones and cartilage can also be determined by examining the thickness of the mucosa in the location and searching for transitions. In embodiments, an array of two or more transducers may be used and the measured mucosal thicknesses compared to locate the transition, as will be discussed in more detail below. In an embodiment, the transition is located by mechanically scanning one or more transducers across the region of interest, taking a plurality of mucosal thickness measurements at points within the region, and indicating to the operator (in real time or retrospectively) when the thickness change exceeds a predetermined threshold corresponding to the transition. For example, the indicator may be an LED that illuminates when the measured thickness of the mucosa changes to indicate that the transducer has moved from over the sphenoid bone to over the palatine bone (or vice versa), as will be discussed in more detail below. In an embodiment, ultrasound scanning may also be used to approximate the path of nerves that are branched below by SPF and nerves that are innervated through the palatine bone. The vertical plate of the palatine bone is anteriorly adjoined by the very thin eggshell cartilage, which is the internal lateral wall of the maxillary sinus. Cartilage in this region was less than.8 mm thick, and palatine bone was-2 mm thick. Using ultrasound, this transition can be detected and feedback provided to the user that they have reached the target area of the posterior nasal nerve. A-mode or B-mode ultrasound measurements may be used to detect the thickness of the palatine and sphenoid bones or otherwise identify a transition between the two bones. In an embodiment, ultrasound may be used to detect differences in the amplitude of signals reflected by a thin palatine bone and a thick sphenoid bone. More energy can pass through the palatine bone, resulting in a lower amplitude reflection. Conversely, the sphenoid bone may reflect more of the signal, resulting in the detection of echoes of greater amplitude.

In an embodiment, the amount of ultrasound energy that propagates beyond the bone interface may be used to identify a transition between two bones in the nasal cavity. For example, the sphenoid bone is relatively thick compared to the palatine bone, and results in increased attenuation of the ultrasound beam via absorption, scattering and/or reflection, and in increased acoustic shadowing (i.e., very low echo intensity in deeper regions) compared to the thinner palatine bone. The relative degree of acoustic shadowing as measured by a-mode signal intensity (indicated by a spike in the a-mode trace) detected at a depth beyond the bone interface can be used to indicate whether the transducer is aimed at a thin or thick bone structure, such as a palatine or sphenoid bone. The transition between the two bones may be identified by scanning the transducer interrogation zone across the region of interest or by using an ultrasound transducer array, as will be discussed in more detail below.

The angle of the axis of the ultrasound beam emitted from the ultrasound transducer relative to the tissue surface can affect the measurement of both ultrasound thickness and doppler flow. In order to provide accurate tissue thickness measurements during a-mode ultrasound scanning, the transducer face needs to be perpendicular to the tissue surface. The measurement error increases in direct proportion to the angle of 90 ° from vertical. Doppler frequency f_dIs related to both the velocity V of the moving particle and the angle theta between its direction of motion and the ultrasonic energy axis. This relationship is described in the following equation:

1.1.1.f_d＝(2*f_t*V*cosθ)/c

1.1.2. wherein:

1.1.2.1.f_tis the frequency of the ultrasonic signal

1.1.2.2.c is the speed of sound in tissue

The factor cos θ approaches zero when the angle θ approaches 90 °. When the doppler transducer is perpendicular to the direction of blood flow, the signal decreases and the flow may become undetectable. For this reason, it is important to maintain the orientation of the transducer relative to the tissue surface. As the sphenopalatine artery passes through the sphenopalatine foramen, the blood vessels are diverted almost 90 ° straight down to pass through the walls of the nasal cavity. In this transition, the direction of the blood vessel and the blood flow changes. By detecting a change in the signal associated with the transition, the user can locate the sphenopalatine foramen and use the marker to guide treatment placement. For example, as the transducer moves along the vessel toward the bore, the doppler signal measured by the transducer may change from a meaningful signal to a negligible signal, indicating that the vessel may become more perpendicular for the transducer beam angle. This may be used as an indication that the hole is nearby, providing an anatomical landmark that may allow for more rapid and/or accurate placement of the probe in the intended ablation region.

The ultrasound scans discussed above, including doppler, a-mode, B-mode, and M-mode, may be performed using various devices including one or more ultrasound units (also referred to as ultrasound transducers), each including an ultrasound transmitter and an ultrasound receiver for producing signals that are processed by a processing unit to generate doppler, a-mode, B-mode, and M-mode scanning signals. In an embodiment, a single component acts as both an ultrasonic transmitter and receiver. As described above, these signals can be used to determine the location of the vasculature in the nasal cavity, the innervation in the nasal cavity, the tissue and bone thickness in the nasal cavity, bony landmarks, and boundaries between tissues of different densities.

In an embodiment, the ultrasound probe 800 may include a shaft 802 and an ultrasound transducer 804 coupled to a distal end 806 of the shaft, for example as shown in fig. 8. The shaft 802 may be straight or may have one or more bends 807 between the distal end 806 and a proximal end 808 coupled to a handle 810. The bend in the shaft may be configured to meet bone structure within the nasal cavity to facilitate insertion into the nasal cavity and contact between the ultrasound transducer and the tissue surface. The bend may form an angle in the range of 30-90 between the distal and proximal ends of the shaft. The distal portion end of the shaft may be between 5mm and 20 mm.

In embodiments, the angle of the ultrasound transducer relative to the longitudinal axis of the distal tip of the shaft may be based on the form of ultrasound with which the probe is intended to be utilized. For example, because the angle of incidence between the direction of blood flow and the energy delivery axis can affect the magnitude of the detected doppler signal, the angle at which the ultrasound transducer is mounted to the distal end of the probe can cause the delivery path of the transducer to align with the axis of the distal arm. Alternatively, the transducer may be mounted such that the axis of the transducer probe is at some non-parallel angle relative to the axis of the arm. The orientation of the transducer probe axis relative to the distal arm may be fixed. In embodiments, the scanning position of the ultrasound transducer may be moved during use by changing the angle of the distal end of the shaft relative to the proximal end of the shaft or by changing the position of the entire device within the nasal cavity. In an embodiment, the orientation of the transducer probe axis relative to the arm may be variable. In embodiments, the scanning position of the ultrasound unit may be changed independently of changing the angle between the distal arm and the shaft or moving the entire device.

In embodiments, the angle between the distal portion of the arm coupled to the ultrasound transducer and the proximal portion of the arm may vary. For example, as shown in fig. 9A-C, a shaft 902 of a surgical probe 900 may include an articulation joint 904 between a proximal end 906 of the shaft and a distal end 908 of the shaft that includes an ultrasonic transducer 910. While the distal portion 908 of the ultrasound probe is positioned within the general area of the nasal cavity where ablation is possible, the articulating joint 904 may be used to pass the ultrasound transducer 910 at the distal tip across the mucosal surfaces of the nasal cavity. At various points in the nasal cavity, or continuously as the ultrasound transducer passes within the nasal cavity, the processing unit instructs the ultrasound transmitter to transmit an output signal and further to receive a detected signal from the ultrasound receiver. The ultrasound output signal passes through the tissue and may be absorbed, transmitted or reflected by internal tissue structures depending on the ultrasound properties of the tissue. The reflected ultrasound energy is received as a detected signal and may be used to identify anatomical features, as discussed above.

In an embodiment, the size of the blood vessel may be measured by scanning the nasal cavity surface with an ultrasound signal and estimating the distance at which a threshold doppler signal is detected. In embodiments, the size of the blood vessel may be measured by physically moving the device containing the fixed position ultrasound transducer (as shown, for example, in fig. 8), or moving the portion of the device with the ultrasound transducer relative to the rest of the device (as shown in fig. 9A-C). Further, in embodiments, a steered ultrasound beam (e.g., with a phased array) may be used to scan the scan area. In an embodiment, pulsed doppler techniques are used at different depths to estimate the thickness of the vessel in a direction parallel to the beam delivery axis.

The processing unit may have a predetermined threshold set of doppler signals corresponding to typical blood flow in a target vessel (e.g., SPA) in order to determine whether the detected blood flow is from a vessel of interest. Wall filters and other processing may be implemented to separate the blood flow from the low-speed clutter signals, which improves the performance of the processing unit when demarcating the vessel boundaries.

In embodiments, the ultrasound probe may pass along the surface of the desired location SPA. For example, as shown in fig. 10A, an ultrasound probe 1000 may be threaded from a first location 1001 to a second location 1002, which in this example are on either side of a SPA 1003. When such a scan occurs, the doppler signal has a peak amplitude at a location between the first location and the second location, as shown in figure 10B. When the processing unit detects a peak as shown in fig. 10B, an alarm in the form of an audio or visual or tactile/haptic indication may be performed to inform the operator that a blood vessel (e.g. SPA) is located. In an embodiment, an alert is provided immediately upon the doppler signal exceeding a previously set threshold corresponding to a threshold associated with expected blood flow of the blood flow being searched. In an embodiment, a full scan from a first location to a second location occurs, peaks from the full scan are identified, and an alert is provided when the ultrasound probe retraces its path back toward the first location.

In embodiments, scanning methods similar to those shown in fig. 10A may be performed with a transducer configured to operate in either a-mode or B-mode, and may be used to detect a maximum thickness, a minimum thickness, or a transitional thickness of soft tissue or bone in order to identify a treatment site for ablation.

In embodiments, the ultrasound probe may comprise more than one ultrasound transmitter and/or more than one ultrasound receiver attached at different parts of the ultrasound probe. In multiple ultrasound transducer embodiments, multiple ultrasound signals corresponding to different locations of the probe may be processed by the processing unit to determine the location of an anatomical feature (such as a SPA or hole) relative to multiple locations on the probe. The ultrasonic transducers may be arranged such that there is a fixed distance between them. The ultrasonic transducers may be arranged in a linear fashion, for example, as shown in fig. 11A. As shown, the probe 1100 includes three ultrasound transducers 1102, including left 1102-1, middle 1102-2, and right 1102-3 aligned on a crossbar 1104 at the distal end of the probe. Crossbar 1104 is perpendicular to the longitudinal axis of the shaft 1106 of the probe. In an embodiment, the angular position of the left and right ultrasound transducers is fixed, and movement is limited to positional offsets that change the proximity of the transducers relative to the center transducer. In embodiments, the insonification angle of the transducer may or may not change with the overall change in position. In embodiments, the ultrasound transducers may be arranged in a rectangular array or a circular array. In embodiments, other spatial configurations including any number of ultrasonic transducers may be used, for example, a configuration with four transducers facing in opposite directions in a circular pattern at the distal end of the probe shaft, and five transducers aligned along the longitudinal axis of the probe shaft, with each transducer facing in the same direction. An array of ultrasound transducers has the advantage of allowing a larger area to be scanned simultaneously and of providing more accurate positioning of anatomical features relative to different parts of the probe.

In embodiments including doppler scanning, when a multi-ultrasound transducer probe is placed near a blood vessel, only the ultrasound transducer that emits a signal incident on the blood flow will detect the doppler shifted signal, while the other ultrasound transducers in the array will not. Thus, the position and/or orientation of the blood vessel may be determined based on detecting or not detecting doppler shifts during a single point in time or during a scan. For example, as shown in fig. 11B, the probe 1100 may be placed in the nasal cavity in the general area where the SPA1108 is located. The probe 1100 may be passed until one or more of the ultrasound transducers 1102 detects a doppler shift indicative of blood flow associated with the SPA 1108. For example, as shown in FIG. 11B, only the left ultrasound transducer 1102-1 is incident on the blood stream through the SPA 1108. Thus, as shown in fig. 11C, only the left ultrasound transducer detects a meaningful doppler signal, while the middle and right transducers do not.

The pattern of transducers that detect doppler signals during the scan can be used to estimate the location of the blood vessel, the orientation of the blood vessel, or to estimate the size of the blood vessel. Detecting the position of a vessel (such as a SPA) relative to a plurality of sensors is advantageous in allowing for more accurate and faster localization of anatomical landmarks. Multiple sensors can simultaneously interrogate a wider range of tissues and thus also allow smaller passes of the ultrasound probe to determine the location of anatomical features using doppler, a-mode or B-mode scanning. For example, as shown in fig. 12A-12F, the cross-bar of the probe 1100 can be passed within the nasal cavity, and the processing unit can analyze the doppler signals from each transducer over a period of time in order to determine the peak signal for each transducer and determine the location of the SPA 1108.

In an embodiment, the ultrasound unit may be positioned on an independently steerable arm that branches off from the main axis of the probe. In an embodiment, the ultrasonic transducers 1302 in the array are movable along a crossbar 1304 of the probe 1300, as shown in fig. 13A and 13B. As shown, the left 1302-1 and right 1302-3 transducers are located in recessed tracks within the crossbar 1304 portion of the probe 1300. The positions of the left 1302-1 and right 1302-3 ultrasound transducer cells may be varied in series or independently, and the center transducer 1302-2 may be coupled to the crossbar 1304 at a fixed location. In embodiments, the position of the transducer is changed using a button, switch, slider, and/or dial located at the proximal handle end of the probe.

In an embodiment, the surgical probe may include a visual indicator that indicates information about the location of the anatomical feature detected by the ultrasound transducer. For example, the visual indicator may provide feedback for adjusting the orientation of the probe used to position the SPA. The visual indication may be displayed with an LCD (or other type of display screen), a single LED, or an array of two or more LEDs. The information about the position may be related by different intensities, different colors, or on/off patterns (i.e. blinking patterns) and/or colors of the plurality of LEDs. In an embodiment, the LED may be a multi-color LED, and the processing unit controls the LED to display different colors based on predetermined thresholds of ultrasound corresponding to different detected thicknesses or distances.

In an embodiment, for example as shown in fig. 14, the ultrasound probe 1400 can include an LED 1402 at the distal tip proximate to the ultrasound transducer 1404. When the probe 1400 passes near the SPA1406, e.g., as disclosed with respect to fig. 10A, the LED 1402 provides an indication when the ultrasound transducer detects a doppler shift produced by blood flow in the SPA. In an embodiment, the LEDs may flash at different rates or patterns to indicate the intensity of the ultrasound signal to locate the anatomical feature. In embodiments that include an LED on the probe, the operator may view the LED directly or visually through a camera imager inside the nasal cavity to receive directional information indicated by the LED to determine the position of the anatomical feature relative to the probe. In an embodiment, the LED corresponding to the ultrasound unit may be outside the nasal cavity when the device is in use.

In an embodiment, the probe may include a plurality of visual indicators corresponding to the plurality of ultrasound transducers. Fig. 15A and 15B show a probe 1500 similar to that of fig. 11A. The probe includes an LED 1503-1, 1503-2 and 1503-3 corresponding to each of the ultrasonic transducers 1502-1, 1502-2 and 1503-3. The LEDs are located near the corresponding ultrasound transducers. The operator may pass the probe within the nasal cavity and the processing unit will adjust the intensity of each LED to correspond to the ultrasonic signal amplitude measured by the corresponding ultrasonic transducer.

In embodiments, the intensity of the LED may vary continuously based on the ultrasonic signal as shown in fig. 16A, or discontinuously based on a preset threshold of the ultrasonic signal as shown in fig. 16B. In an embodiment, the intensity of the LED may be varied based on time-of-flight pulse echo ultrasound measurements of the distance to a highly reflective tissue interface (such as a sphenoid bone). Further, in an embodiment, the processing unit may display the amplitude of the ultrasound unit on a display. In an embodiment, the processing unit may display an image indicating the location of an anatomical feature (e.g., SPA).

In embodiments, the ultrasound transducer and probe, e.g. as disclosed above, may be part of a surgical probe comprising an ablation element, in particular a cryoablation element. Fig. 17A-17D show views of the distal end of an embodiment of a surgical probe, particularly an ablation probe, including an expandable membrane structure that can be used when a target treatment site is located. The illustrated ablation probe is an example, and other cryoablation probes as well as other types of ablation probes may be used with the disclosed ultrasound techniques disclosed herein. The ablation probe is configured with an expandable membrane structure that serves as a liquid cryogen vaporization chamber. Liquid cryogen enters the interior of the expandable membrane structure. The vaporized cryogen gas exits the interior of the expandable membrane structure through a fenestration 147 in the distal end 146 of the probe shaft 145 and exits proximally into the room.

As shown in fig. 17A, the structure or member 83 is formed as a ring-like and elongated structure having arcuate edges to present an atraumatic surface. The structure 83 may be formed of a relatively rigid wire or spring-like material that retains its configuration when pressed against a tissue surface. The structure 83 may form a continuous structure defining an opening therethrough, such as a ring or elongated ring-shaped member that is opened by a ring. The structure 83 may be completely contained within the expandable structure 81, and the expandable structure 81 may be formed to have a predetermined shape that may or may not be expandable when inflated with a cryogen. Further, expandable structure 81 may be formed to completely surround structure 83 without being supported by or attached to structure 83 itself. Such structures 83 may provide a configuration that presents a low-profile as the device is advanced into and through the nasal cavity and between the nasal turbinate tissues. However, due to the relatively flattened shape and rigidity and integrity of the structure 83, the structure 83 may be used to manipulate, move or otherwise distract the tissue of the nasal cavity without having to rely on the expandable structure 81. In addition, the low profile enables the structure 83 to be desirably positioned within a narrow range, such as near the cul de sac of the posterior nasal nerve. When expandable structure 81 is in its collapsed state, it may form a flattened shape, and when inflated, expandable structure 81 may expand to a configuration that remains unsupported or attached to structure 83. Because the structure 83 can be formed of a member that is solid along its length, cryogen can be introduced directly into the expandable structure 81 through a distal opening defined in the probe shaft 145.

In embodiments, the structure 83 may be formed from a hollow tubular member that is itself formed into a continuous or annular shape. In such embodiments, the cryogen may optionally be introduced through the hollow tubular member and dispersed within the interior of the expandable structure 81 through one or more openings that may be defined along the tubular member. In yet another alternative, structure 83 may be formed in a flat shape rather than an annular shape. In this configuration, the structure may be solid or hollow such that the cryogen may be introduced through the structure and into the interior of the expandable structure 81 via one or more openings defined along the structure.

The structure 83 may extend and remain attached to the probe shaft 145, but the remainder of the structure 83 extending within the expandable structure 81 may remain unattached or unconnected to any portion of the expandable structure 81. Thus, once the expandable structure 81 is inflated with a cryogen, the structure 83 can be adjusted into position or moved by manipulating the probe shaft 145 relative to the interior of the expandable structure 81 to achieve targeted positioning and cooling of the tissue region while in contact with the outer surface of the expandable structure 81. For example, the structure 83 may be pressed laterally against a particular region of underlying tissue to stretch or thin the contacted tissue region to facilitate cryotherapy. When the structure 83 is adjusted in position relative to the expandable structure 81, the expandable structure 81 can be held in a resting position against the contacted tissue region, thereby allowing limited repositioning of the structure 83 therein.

In embodiments, structure 83 may be partially attached at specific portions of structure 83 along the interior of expandable structure 81 or attached along the entire structure 83. For example, structure 83 may be integrally attached, adhered, or otherwise coupled to expandable structure 81, while in other variations a distal portion of structure 83 may be attached, adhered, or otherwise coupled to a distal portion of expandable structure 81, while in other variations portions of structure 83 may be attached, adhered, or otherwise coupled to expandable structure 81 along sides thereof. Any of these variations may optionally be utilized depending on the desired interaction and treatment between structure 83, expandable structure 81, and the underlying tissue region to be treated.

In embodiments, the lumen 84 for introducing cryogen into the interior of the expandable structure 81 may extend beyond the distal end of the probe shaft such that cryogen is released at a more distal location within the interior. As shown, cryogen cavity 84 may be supported along structure 83, for example, via a rod or member 85 extending across structure 83. This particular variation may allow a cryogen to be introduced into the distal portion inside expandable member 81. This variation or a variation in releasing cryogen from the opening of the probe shaft may be utilized as desired.

Fig. 17B illustrates a side view of the embodiment of fig. 17A, showing how structure 83 may be formed from a relatively flat configuration relative to an inflated expandable structure 81. Due to the structural integrity of structure 83 and its relatively flat profile, structure 83 may provide for targeted treatment of tissue when contacted by a device. FIG. 17C shows a side view of the expanded expandable structure 81 as the expanded expandable structure 81 is pressed in a longitudinal direction against the underlying tissue surface S by its distal tip. The relative strength of the structure 83 provides the ability to press the device against the tissue surface so that the remainder of the expandable structure 81 can maintain its expanded configuration to potentially isolate other surrounding tissue regions. Fig. 17D similarly illustrates the device when the structure 83 is laterally pressed along its sides against the tissue surface S such that the structure 83 lies flat. The contacted tissue region may be treated while the remaining portions of the surrounding tissue are potentially isolated by the expanded structure 81. Other exemplary ablation devices for use in the present invention are described in U.S.14/503,060 filed on 30/9/2014 and U.S.62/408,920 filed on 17/10/2016, the contents of which are incorporated herein by reference in their entirety for all purposes.

In an embodiment, the ultrasound transducer may be attached to a support member within the balloon, as shown in fig. 17A. In embodiments, the balloon may be selectively filled and emptied with an acoustic couplant (such as a gel or fluid). In embodiments, the balloon is filled with a fluid to allow for better acoustic coupling during ultrasound sensing and localization, then the fluid is expelled once the device is in place, and ablation is desired, for example by releasing a cryogen into the area surrounded by the balloon. In an embodiment, the ultrasound transducer 1702 is mounted on a ring-shaped support structure 83 as shown in fig. 17A and 18A-C, and can be used to scan tissue within the nasal cavity, as discussed herein.

In an embodiment, the ultrasound probe and the ablation probe may be integrated into a single probe having a single axis. For example, as shown in fig. 19A, the shaft 1902 of the probe 1900 may include an ultrasound transducer 1904 and an ablation element portion 1906 at the distal end, e.g., a cryoballoon along the shaft of the probe. In an embodiment, as shown, for example, in fig. 19B and 19C, the shaft may include an articulating joint 1908 that may be used to scan with the ultrasound probe while the cryoablation element remains stationary or requires less movement relative to the ultrasound transducer.

In embodiments, the integrated probe may include a plurality of ultrasound transducers for locating an anatomical feature, such as a SPA or bony landmark as disclosed above. The ultrasound transducer may be positioned at any location along the longitudinal axis of the probe, the cryoablation element, or an auxiliary shaft including a crossbar. For example, as shown in fig. 20, the integrated probe 2000 includes a crossbar 2002 with three sets of ultrasound transducers 2004 at the distal end, and an ablation member 2006 along an axis 2008. Further, in embodiments, the ultrasound transducer may be attached to a balloon of the cryoablation element. For example, as shown in fig. 21, the balloon 2106 at the distal end of the shaft 2108 of the probe 2100 may include an ultrasound transducer 2104 at the distal end and the ultrasound transducer 2104 along a border around the longitudinal axis of the probe shaft. As another example, as shown in fig. 22, balloon 2206 may comprise an ultrasound transducer 2204 along a planar boundary about an axis perpendicular to the longitudinal axis of the probe shaft. Fig. 21 and 22 show the ultrasound transducers mounted to the outer surface of the balloon, however in embodiments one or more or all of the ultrasound transducers may be mounted to the inner surface of the balloon or otherwise enclosed within the interior of the balloon. An advantage of positioning the ultrasound transducer inside the balloon is the ability to use additional acoustic coupling mechanisms, such as those described elsewhere in this disclosure.

As disclosed above, a plurality of ultrasound units may be used by the processing unit to more accurately and/or more quickly locate SPAs or other blood vessels or anatomical features. For example, the processing unit may acquire signals from each individual ultrasound unit and analyze the signals to generate directional information about the position of the SPA relative to the cryoablation elements. In an embodiment, the signals from the individual ultrasound transducers may be combined or averaged prior to processing. For example, during a-mode scanning or B-mode imaging, multi-element transmit and receive arrays may provide benefits including improved lateral image resolution.

When the target treatment site is determined with one or more ultrasound transducers of the integrated probe based on correlation with the location of the detected anatomical feature, the probe can be positioned at the target treatment site and ablation of the PNN can be performed to treat rhinitis. In embodiments, detection of anatomical features (e.g., SPAs) can be performed continuously before and/or during ablation to provide the advantage of real-time target treatment site detection relative to the probe as ablation is performed.

In an embodiment, for example as shown in fig. 23A, the ultrasound transducer 2302 can be offset from the center 2303 of the cryoablation element 2304 and the center of ablation such that ablation can occur when the ultrasound transducer is positioned over a blood vessel 2305 (e.g., SPA), and thus prevent direct treatment of SPA. For example, the ultrasound transducer may be offset from the center of the ablation probe and the treatment center by a distance "d", where the distance corresponds to the distance between the blood vessel to be avoided and the nerve to be treated. The ultrasound transducer 2302 may be offset in a lateral direction as shown in fig. 23A or in a distal direction as shown in fig. 23B-23D. During an ablation procedure, a surgical probe may be advanced into the nasal cavity and an offset ultrasound transducer may scan the tissue as disclosed above in order to locate the blood vessel. The transducer is over a blood vessel (e.g., the SPA shown in fig. 23A-D), and the cryoablation element is not over the SPA. The ultrasound transducer is held stationary and continues to detect the flow of SPA blood, ensuring that the SPA is not centered in the ablation zone and does not receive direct therapy, cryoablation.

In embodiments utilizing an integrated ultrasound and ablation surgical probe, the relative position of the ultrasound transducer with respect to the ablation probe may be fixed or may be variable. In embodiments with a variable distance between the ultrasound transducer and the cryoablation element, the distance at any time may be measured, for example, with a sensor, and used by the control system to change ablation parameters. In embodiments, the probe may provide an indication if the variable distance detected is not large enough to avoid tissue damage in the SPA area.

Fig. 24A and 24B illustrate an embodiment of a combined ablation and ultrasound sensing probe 2400 configured to interrogate the posterior fontanelle, palatine 2402 and sphenoid 2403, as well as surrounding tissue. As disclosed above, a-mode ultrasound scanning may reflect signals that allow for differentiation of mucosal tissue, bone, and bone and cartilage boundaries of different thicknesses. For example, differences between the thin cartilage of fontanel and the thin palatine bone and/or thick sphenoid bone can be detected. One way in which the signals may be distinguished may be the amplitude of the reflected signal. In an embodiment, a plurality of ultrasound transducers 2406 may be coupled to the probe shaft 2408 both more distally of the cryoablation element 2410 and more proximally of the cryoablation element 2410, for example as shown in fig. 24A. Two ultrasonic transducers may be used to detect anatomical features on either side of the cryoablation element. For example, an ultrasound transducer may be used to detect different thicknesses or compositions of tissue 2405 corresponding to a target treatment site for a nerve. To detect this difference, the probe 2400 is advanced into the nasal cavity and scanned along the tissue within the nasal cavity until the distal transducer detects a signal characteristic of one tissue configuration and the proximal transducer detects a signal characteristic of a different tissue configuration. For example, in locating the transition between a thin palatine bone and a thick sphenoid bone, the device is advanced to a point where the distal transducer detects a reflected signal characteristic of thick bone and the proximal transducer detects a reflected signal characteristic of thin bone or cartilage. Once this location is determined, the operator has confidence as to how deep within the nasal cavity the ablation probe is positioned, and can further maneuver the probe from that point into the desired region for treatment (e.g., in the region of the PNN) and begin ablation, as needed. In embodiments, probe 2400 can be used to measure mucosal thickness to determine the time of administration. For example, the tissue surrounding the treatment area may be 1-5mm thick. If the tissue is less than 3mm thick, the flow rate or discharge time of the vaporized cryogenic liquid in the cryoablation element can be reduced to ensure that ablation does not penetrate deep and damage tissue not in the target treatment area. In embodiments, the bone/soft tissue change is used as an indication of the location of the treatment site. A transition to 0.5-1mm thick cartilage of 1-3mm thick bone may indicate that the probe has reached the vertical plate of the palatine bone (where the nasal cavity is innervated), and this transition may be used to determine the target treatment site. In embodiments, the bone-to-bone transition between the palatine bone and the sphenoid bone may be detected by a transition from a bone thickness of 1-3mm to a bone thickness of > 4 mm. In embodiments, the position of the palatine canal may be determined so as to avoid treatment of nerves within the palatine canal. In an embodiment, for example as shown in fig. 24B, a single ultrasound transistor 2406 of the probe 2400 can be used to detect bone and tissue thickness and transitions, as discussed with respect to fig. 24A.

In an embodiment, such as shown in fig. 25A-C, the ultrasound transducer 24 is configured as an array on a lateral side of the ablation probe, the ultrasound transducer is positioned a distance r from the center of the ablation zone and away from each other at an angle α to define a region within the ablation zone, if an artery is identified within the region, the device provides notification of no ablation or will prevent ablation from being activated if the artery is identified, the radius may be defined at 1-8mm, preferably 6mm, the angle between the transducers may be 5-180 degrees, preferably 45-90 degrees, the number of transducers may be 2-10 fig. 25A shows a lateral face of the embodiment fig. 25A. probe 10 includes an integrated sensing element 23 with an embedded ultrasound transducer 24 and an ablation element 22 attached to a cannula 21. the sensing element 23 is attached to the bottom or top of the cannula 21 in line with the vertical axis of the lateral plane to keep the profile in the horizontal axis as low as possible if the sensing element is attached to the bottom or top of the cannula 21 in line with the vertical axis of the ablation zone in line with a visual or lateral plane to keep the profile in the horizontal axis as low as possible from the ultrasound transducer to the ablation head or box, and to indicate that a rigid probe is positioned in a nasal dilator, if the probe is positioned in a nasal wall, the probe is not in a rigid way, and the probe is positioned in a rigid nasal wall, the probe is able to be moved forward direction, and a rigid probe is moved forward direction, and the probe is moved to indicate that a rigid nasal wall of the probe is moved forward direction, the probe is moved forward, if the probe is moved forward direction, the ablation zone, the ablation probe is moved forward, the ablation probe is moved, and the ablation probe is moved forward, the ablation probe is moved, the probe is moved forward, the ablation zone, the probe is moved forward, the probe is moved, the ablation probe is moved, the probe is moved forward direction, and the probe is moved forward direction, the ablation probe is moved, the ablation zone, the probe is.

In an embodiment, the cryoablation element can be slidably coupled to a probe shaft of an ultrasound probe, for example, as shown in fig. 26A-D. As shown in fig. 26A, the ultrasound probe 2600 includes a shaft 2602 with an ultrasound transducer 2604 disposed at a distal end. The ultrasonic probe 2600 can be inserted into the nasal cavity with the cryoablation element 2606 held outside the nasal cavity. The ultrasound probe 2600 is within the nasal cavity and the ultrasound transducer 2604 can be swept along tissue within the nasal cavity in order to detect anatomical features, such as blood vessels or anatomical features (e.g., tissue thickness, bone thickness, transition/boundary) as discussed above. A target treatment region may be determined based on the determined location of the anatomical feature. For example, as shown in fig. 26B, the anatomical feature may be an SPA, and the target treatment site may be determined to be a predetermined distance from the SPA corresponding to the distance between the SPA and the PNN. The ultrasound transducer 2604 is held against the SPA and the cryoablation element 2608 is advanced along the shaft 2602 of the ultrasound probe, as shown, for example, in fig. 26C. In embodiments, the cryoablation element can be advanced through a lumen in the ultrasound probe, or the shaft of the ultrasound probe can be used as a track. For example, the cryoablation element 2606 is coupled to a shaft 2608, both having a lumen that surrounds the shaft 2602 and slides over the shaft 2602. As shown in fig. 26C, the cryoablation element can include an expandable structure having a lumen that slides around and along the axis of the ultrasound probe. As shown in fig. 26D, the cryoablation element 2606 can be advanced from the ultrasound transducer to a predetermined distance "D" and ablation can be performed at the target treatment site. In embodiments, the ultrasound probe may be configured like a flexible or rigid guidewire through which the ablation probe may be guided to the ablation site. The use of an ultrasound probe as a guide for the slidable cryoablation element is advantageous because it allows the target treatment site to be located with a small device and further allows the cryoablation probe to reach the target treatment site more accurately than without a guide device.

In embodiments, the sensing or combined ablation and sensing probe may comprise a stabilizing element. Relative tissue/transducer motion parallel to the ultrasound transmit angle but not related to blood flow may add unwanted noise to or confound the doppler measurement. For example, slight shifts in the position of the probe, such as those caused by the shaky hand of the operator holding the probe, that occur while the measurement is being taken, can produce a doppler-type effect. This can reduce the performance of positioning the SPA and thus prolong the operating time or lead to errors in determining the correct treatment position. In embodiments, an inflatable balloon may be attached to the shaft of the probe and used to stabilize the ultrasound transducer while performing an ultrasound scan. When a doppler scan is to be performed, the balloon is inflated and transient pressure is exerted on nearby structures as a way to stabilize the position of the probe relative to the surrounding tissue, thereby reducing blood flow independent motion and improving the accuracy of the doppler signal. The balloon may be deflated when repositioning of the probe is desired. The balloon may be re-inflated when additional doppler measurements are taken. For some doppler measurements, such as when the ultrasound probe is rapidly passed through the nasal cavity in a "scanning mode" (where accuracy is less important than general information), the stabilizing balloon may not be inflated. In embodiments, a single stabilizing balloon is used. In embodiments, multiple balloons may be used, such as a stabilizing balloon located on either side of the ultrasound transducer. In embodiments with multiple transducers, multiple balloons may access some or all of the transducers. In an embodiment, the balloon may comprise an ultrasound transducer. In an embodiment, the transducer may be attached to the exterior of the balloon. In addition to the balloon, the stabilization mechanism may include suction, winding, and tines extending from the probe for stabilizing the position of the probe.

In an embodiment, the quality of the acoustic coupling between the ultrasound transducer and the tissue is important to achieve accurate measurements of all ultrasound modes. Without proper acoustic coupling, large reflections at the transducer/air interface substantially prevent the ultrasound waves from reaching the tissue. One mechanism for ensuring mass acoustic coupling is to place the ultrasound transducer directly in contact with the tissue so that there is no air gap. To help ensure adequate contact, suction may be employed. The lumen may be incorporated through the shaft of an ultrasound probe containing one or more ultrasound transducers. Air may be pushed or pulled through the lumen. One or more openings may be placed at the distal end of the probe, proximate the ultrasound transducer. When the ultrasound transducer is brought into proximity with the tissue, suction may be applied to the opening near the transducer, and the suction may pull the transducer closer to the tissue until the opening comes into contact with the tissue and locks the device in place. Suction may be maintained during the ultrasound measurement to ensure sufficient contact for mass energy coupling and signal transmission across the tissue-transducer interface. Ablation also depends on contact between the ablation member and the tissue surface. The above-described systems and methods may be used wherein the opening is proximal to the ablation member and wherein suction is applied to create sufficient contact during treatment.

In an embodiment, the ultrasound signals from the cryoablation treatment period may be analyzed by the processing unit to determine if the mucosa or blood vessels (e.g., SPA) are damaged during the treatment period. For example, blood flow through the SPA during ablation may be monitored, and the detected blood flow may be used to determine the duration of ablation. Ablation may be terminated if a decrease in blood flow below a preset threshold is detected. In embodiments, the target ablation site may be located immediately adjacent to the identified SPA, e.g., 1-5mm, in order to avoid direct freezing of the SPA.

Embodiments include methods for treating rhinitis in a patient, comprising advancing a surgical probe into a nasal cavity of the patient. The surgical probe can include an elongate probe shaft having a proximal end and a distal end, a handle coupled to the proximal end, an ultrasound transducer coupled to the probe shaft, and a cryoablation element coupled to the probe shaft. The method can further include determining a location of a target treatment site within the nasal cavity with the ultrasound transducer, positioning the cryoablation element at the target treatment site location; and cryoablating the target treatment site so as to ablate the at least one nasal nerve to reduce the at least one symptom of rhinitis.

In an embodiment, the method may further include determining a location of the target treatment site, which includes detecting a relative thickness of mucosal tissue in the nasal cavity with the ultrasound transducer to identify an anatomical landmark associated with the location of the target treatment site.

In an embodiment, the method can further include determining the location of the target treatment site by detecting a relative thickness of a palatine bone or a sphenoid bone in the nasal cavity with the ultrasound transducer to identify an anatomical landmark associated with the location of the target treatment site.

In an embodiment, the method may further comprise determining the location of the target treatment site by detecting a relative boundary or transition (transition) between two bones in the nasal cavity or between a bone and cartilage in the nasal cavity with the ultrasound transducer to identify an anatomical landmark associated with the location of the target treatment site. The transition may include 0.5-1mm of cartilage adjacent to 1-3mm of bone used to identify the vertical term (close) of the palatine bone.

In embodiments, the method can further comprise using a surgical probe further comprising a second ultrasound transducer coupled to the probe shaft. An ultrasound transducer may be coupled to the probe shaft relative to the distal end of the probe shaft and the distal side of the cryoablation element. A second ultrasound transducer can be coupled to the probe shaft relative to the proximal end of the probe shaft and the proximal side of the cryoablation element. Determining the location of the target treatment site may include detecting a tissue property with both the ultrasound transducer and the second ultrasound transducer.

In an embodiment, the method can further include detecting a tissue property with the ultrasound transducer and the second ultrasound transducer to determine the location of the target treatment site by identifying a relative mucosal tissue thickness indicating that the cryoablation element is positioned proximate the target treatment site.

In an embodiment, the method can further include detecting a tissue property with the ultrasound transducer and the second ultrasound transducer to determine the location of the target treatment site by identifying a relative bone thickness indicating a location of the cryoablation element positioned proximate to the target treatment site. The relative bone thickness may indicate that the ultrasonic transducer detected a sphenoid bone and the second ultrasonic transducer detected a palatine bone.

In an embodiment, the method can further include cryoablating the surgical probe with the ultrasound transducer coupled to the probe shaft at a predetermined distance relative to each other. The predetermined distance may correspond to a distance between an anatomical feature detectable with the ultrasound transducer and the at least one nasal nerve. Determining the location of the target treatment site may include locating the anatomical feature with an ultrasound transducer. Cryoablation of the target treatment site may include ablating at least one nasal nerve when the ultrasound transducer detects a signal indicative of the proximity of the ultrasound transducer to the anatomical feature.

In embodiments, the method may further comprise the anatomical feature being a blood vessel.

In an embodiment, the method may further comprise advancing the surgical probe into the nasal cavity by detecting a middle turbinate in the nasal cavity with the ultrasound transducer to determine that the surgical probe is being advanced through the middle meatus.

In an embodiment, the method can further include the probe shaft including a surgical probe configured to facilitate articulation of the ultrasound transducer relative to the cryoablation element. Determining the position of the target treatment site with the ultrasound transducer may include articulating the ultrasound transducer with an articulation joint to scan a tissue region within the nasal cavity.

In embodiments, the method can further include a surgical probe having a light emitting element coupled to the probe shaft. The light emitting element can emit a visual indication within the nasal cavity when the position of the target treatment site is determined.

In embodiments, the method can further include a surgical probe having a tactile feedback element coupled to the handle. The tactile feedback element may issue a tactile indication when the position of the target treatment site is determined.

In embodiments, the method can further include a cryoablation element including an expandable structure. Further, cryoablating the target treatment site may include expanding the expandable structure by vaporization of a cryogenic fluid within the expandable structure.

In an embodiment, the method can further include monitoring a size of an iceball formed while cryoablating the target treatment site with the ultrasound transducer coupled to the probe shaft or a second ultrasound transducer. The ultrasound transducer or a second ultrasound transducer may emit an ultrasound beam at an angle relative to the longitudinal axis of the probe shaft so as to traverse (intersect) tissue in the nasal cavity where an iceball is formed.

In an embodiment, the method may further comprise terminating cryoablation when the size of the ice ball reaches a predetermined size range.

In embodiments, the method can further include a cryoablation element slidably coupled to the probe shaft. In an embodiment, after determining the location of the target treatment site, the cryoablation element is advanced into the nasal cavity by sliding the cryoablation element along the shaft toward the distal end of the surgical probe shaft to the target treatment site.