WO2012066464A2

WO2012066464A2 - Oropharyngeal airway support assembly

Info

Publication number: WO2012066464A2
Application number: PCT/IB2011/055070
Authority: WO
Inventors: Sody Naimer
Original assignee: Sody Naimer
Priority date: 2010-11-15
Filing date: 2011-11-14
Publication date: 2012-05-24
Also published as: WO2012066464A3

Abstract

An aspect of embodiments of the invention relates to a removable airway support assembly for maintaining patency (the state of being open) of the oropharynx. The removable support assembly includes an oropharyngeal airway stent (hereinafter "stent") and a fixation member for securing the stent in place in the oropharynx. The airway support assembly may further include an arm connecting the stent to the fixation member.

Description

OROPHARYNGEAL AIRWAY SUPPORT ASSEMBLY

RELATED APPLICATIONS

[0001] The present application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application 61/413,483 filed on November 15, 2010, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] Embodiments of the disclosure relate to an assembly for maintaining patency of human airway passages.

BACKGROUND

[0003] Obstructive sleep apnea (OSA), is a common sleep disorder in which patients suffer from brief interruptions in breathing during sleep. OSA is estimated to have a prevalence of about 2% in women and about 4% in men. OSA is believed to have a high impact on health and involve an increased risk of cardiac disease, hypertension, stroke and impotence. Additionally, OSA may have a short-term effect on daytime alertness and may lead to hyper- somnolence.

[0004] In most patients, OSA causes a repetitive obstruction in the posterior pharynx during sleep, in which the soft palate extends to a region at the base of the tongue and obstructs or completely closes the patients airway passages. As the airway closes, breathing stops and the patient awakens. These breath interruptions are brief but prevent the person from having continuous sleep. The relaxation of the muscles in the pharynx may also be the cause of snoring. Air flowing over the relaxed soft palate causes the vibrate creating the snoring sound.

[0005] There are several alternative treatments for OSA and/or snoring, one of which is a behavioral positional treatment. Apneas tend to increase when sleeping on the back as gravity makes it more likely for the tongue to fall back over the airway and for the airway muscles and other tissue such as the tonsils to relax and block the airway. Behavioral positional treatment involves training a patient to sleep on his side. However, this treatment is not always successful, and can limit patients' comfort when sleeping.

[0006] A different approach of treating OSA involves weight loss. In some cases, additional fat around the neck may make a person's airway passage narrower, making obstructions more likely to occur. For some overweight people, especially those with mild cases of OSA, losing weight can relieve sleep apnea symptoms.

[0007] One of the most common devices for treating OSA is the Continuous Positive Airway Pressure (CPAP) device, which works by gently blowing pressurized room air through the airway at a pressure high enough to keep the throat open. The pressure is set according to the patient's needs at a level that eliminates the apneas that cause awakenings and sleep fragmentation. CPAP devices require continuous power to operate, tend to make noise, and prevent motion while sleeping.

[0008] OSA can also be treated by surgery, which usually requires general anesthesia. There are several surgical procedures available for treating OSA, which use different techniques to increase size of a patient's airway passage and therefore reduce obstructive occurrences.

SUMMARY

[0009] An aspect of embodiments of the invention relates to a removable airway support assembly for maintaining patency (the state of being open) of the oropharynx. The removable support assembly includes an oropharyngeal airway stent (hereinafter "stent") and a fixation member for securing the stent in place in the oropharynx. The airway support assembly may further include an arm connecting the stent to the fixation member.

[00010] The airway support assembly can prevent or at least mitigate OSA by maintaining an open airway in the posterior pharynx and enabling steady airflow in multiple postures, including lying on the back, during sleep. In certain embodiments of the invention, the stent maintains an open airway when the patient is breathing and closes under pressure exerted when the patient swallows.

[00011] In certain embodiments of the invention, the stent maintains patency of the airway using a minimal surface area of the stent in contact with oropharyngal tissue.

[00012] In the discussion unless otherwise stated, adjectives such as "substantially" and "about" modifying a condition or relationship characteristic of a feature or features of an embodiment of the invention, are understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended. [00013] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF FIGURES

[00014] Non-limiting examples of embodiments of the invention are described below with reference to figures attached hereto that are listed following this paragraph. Identical structures, elements or parts that appear in more than one figure are generally labeled with a same numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are chosen for convenience and clarity of presentation and are not necessarily shown to scale.

[00015] Fig. 1 schematically shows an airway support assembly in accordance with an embodiment of the invention;

[00016] Fig. 2 schematically shows another airway support assembly in accordance with an embodiment of the invention; and

[00017] Fig. 3 schematically shows an airway support assembly positioned in a human subject in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

[00018] In the following detailed description, components and operation of a removable airway support assembly are described and discussed with reference to Figs. 1-3.

[00019] Fig. 1 schematically shows a removable airway support assembly 100 in accordance with an embodiment of the invention. Airway support assembly 100 comprises an oropharyngeal airway stent 102 (hereinafter "stent"), an arm 112 and a fixation member 114.

[00020] Stent 102 may be formed as a substantially cylindrical flexible structure having a certain length and configured to maintain patency of the airway in the oropharynx by providing physical support to the oropharyngeal airway. According to an embodiment, stent 102 may be shaped as a circular cylinder- shaped or elliptical cylinder-shaped mesh.

[00021] According to an embodiment of the invention, the length of stent 102 is from between about 15 and about 35 mm. According to an embodiment of the invention, the inner diameter of stent 102 when opened is between about 6 and about 10 mm. [00022] In an embodiment, stent 102 may be made of a material such as a metallic shape-memory alloy, silicone, polyurethane, rubber or any other elastomer, which allows the stent to maintain elastic characteristics and enables the patient to perform routine swallowing movements. During swallowing, the swallowing mechanism applies sufficient pharyngeal pressure, which temporarily causes stent 102 to close. Once the swallowing process ends, stent 102 returns to its normal open position and reopens the oropharyngeal airway. The ability of the stent to close when in place in the human pharynx allows for comfortable swallowing, thereby enabling the patient to swallow saliva which accumulates in the mouth before and during sleep.

[00023] In an embodiment of the invention, stent 102 is configured to remain open and maintain patency of the oropharyngeal airway under pressure of up to 15 centimeters of water (cmH₂0). Stent 102 can be configured to close, completely or partially, when pressure of 50-60 cmH₂0 is applied, which is typically the pressure exerted while swallowing, thereby allowing the patient to comfortably swallow while stent 102 is in place in the oropharynx.

[00024] The pharynx is a highly sensitive region and can be easily irritable by introduction of a foreign object. The pharyngeal reflex (gag reflex) and resistance to foreign objects are correlated to the foreign object's texture and surface area. Hence, stent 102 may be made from a relatively smooth material and may be configured to have a relatively small external surface area to limit contact of the stent with oropharyngal tissue when the stent is in position during sleep. The smoothness of the material and relatively small contact area of a stent and oropharynx tissue in accordance with an embodiment of the invention tends to moderate the gag reflex while still maintaining an opening wide enough to allow adequate air flow through the posterior pharynx.

[00025] To configure a stent having a relatively small external surface area in accordance with an embodiment of the invention, the stent may be configured having an external surface formed having a plurality of empty regions, that is lacunae. Let A_L be an area equal to that of the lacunae. Let A_s be the external surface area of the stent. A figure of merit referred to as a "contact index" "Cf which may be used to measure how effective a stent configuration is in reducing contact of the stent with oropharynx tissue is defined by an expression:

[00026] C- = A_s /( A_s + A_L).

[00027] In an embodiment of the invention a contact index C_∑ is equal to or less than about 0.8 and greater than 0.01. [00028] By way of numerical example, assume that the open spaces (lacunae) in a representative cm 2 of surface of mesh stent 102 have a surface area (A ) of 0.33 cm 2 and the mesh material has a surface area (A ) of 0.66 cm . Then C_∑ ~ 0.66.

[00029] For a stent in the shape of a coiled spring the open spaces (lacunae) in a representative cm 2 of surface have a surface area (A_L) of 0.9 cm 2 and the mesh material has a surface area (A ) of 0.1 cm². Then C. « 0.1.

[00030] Stent 102 is made from a mesh like material and has a C_∑ of less than 1. Other examples of stents having a C_∑ of less than 1 are stents made of porous material and stents constructed from wire or ribbon-like material.

[00031] Stent 102 may be formed of non-toxic material or combination of materials, optionally devoid of foul odor or taste.

[00032] Optionally, stent 102 may further include a local anesthetic aimed at enhancing tolerance of the tissue of the oropharynx to foreign bodies and suppressing the gag reflex. In an embodiment of the invention, the anesthetic is selected from the group consisting of: amylocaine, benzocaine, butacaine, butamben, chloroprocaine, dimethocaine, meprylcaine, metabutoxycaine, orthocaine, propoxycaine, procaine, proxymetacaine, risocaine, tetracaine, cyclomethycaine, hexylcaine, piperocaine, articaine, bupivacaine, levobupivacaine, ropivacaine, carticaine, cinchocaine, etidocaine, lidocaine, mepivacaine, prilocaine, and trimecaine.

[00033] In an embodiment of the invention, the topical anesthetic is applied to the stent shortly before insertion. In another embodiment, the stent is drug-eluting and is manufactured to release topical anesthetic when the stent is in contact with the oropharyngal tissue. In a further embodiment, the stent is coated with a biodegradable polymer admixed with a topical anesthetic which slowly releases the topical anesthetic when the stent is in place and is in contact with human tissue. Examples of biodegradable polymers include polyamides, polyesters, polyanhydrides, polyorthoesters, and polycarbonates. Drug eluting stents are further described in United States Patent Number 6,656,162 and United States Patent Number 5,972,027.

[00034] Airway support assembly 100 is suited for use when stent 102 is located at the interface between the base of the tongue and the anterior retropharynx. Using airway support assembly 100 when stent 102 is not in its desired position is undesired, especially during sleep, and may lead to irritation or rejection. Therefore, airway support assembly 100 includes a fixation member 114 for securing stent 102 in its intended location.

[00035] Fixation member 114 may be shaped as a teeth guard, a mouth guard, a posterior teeth fixation plate, a set of straps, a harness, a palate retainer or a similar device. In the figure, fixation member 114 is shown, merely as an example, having the shape of a teeth guard made of a soft resilient, flexible material curved according to the curvature of the teeth line. As the patient bites on the fixation member and clamps his jaws together, the fixation member is secured in place. In an embodiment of the invention, a fixation member may be affixed to a tooth or to a plurality of teeth and removable by the patient.

[00036] Airway support assembly 100 may optionally include an arm 112 configured for connecting stent 102 to fixation member 114. In an embodiment where such an arm is not present (not shown), the stent may be directly connected to the fixation member.

[00037] Additionally, arm 112 may be designed to least interfere with the natural swallowing and breathing mechanism and may enable personal adjustment of airway support assembly 100 to fit the patient's anatomy. In an exemplary embodiment, the arm comprises a wire that is 0.5-2mm in diameter.

[00038] In order to configure airway support assembly 100 to fit in a patient's mouth and maintain patency of the oropharyngal airway, measurements of the patient's mouth and oropharynx are taken before construction of airway support assembly 100. In addition, for proper fit of fixation member 114, measurements of the patient's mouth may be taken by dental impression and mold formation and/or by measurement of dimensions of mouth and oropharynx. One way to adjust the airway support assembly to patient's anatomy is to adjust arm's 112 length either by trimming at the time of the initial fitting of the assembly, or by allowing the arm 112 to partially fold as necessary into the fixation member itself. As another example, arm 112 may be a telescopic arm, including multiple segments collapsible into one another.

[00039] Fig. 2 schematically shows a removable airway support assembly 200 in accordance with an embodiment of the invention. Airway support assembly 200 includes an oropharyngeal airway stent 202 (hereinafter referred to as "stent"), an arm 212 and a fixation member 214.

[00040] Stent 202 may be formed as a substantially cylindrical flexible structure having a certain length, for example, between 15 and 35 mm, and configured to maintain an open airway in the posterior pharynx by providing a physical support to the oropharyngeal airway. According to an embodiment, stent 202 may be shaped as a helical coil.

[00041] Stent 202 may be made of the same material as stent 102 appearing in Fig 1, which enables the patient to perform routine swallowing in a way, which is similar to the way enabled by stent 102 appearing in Fig 1.

[00042] Stent 202 has a C_∑ of less than 1 , thereby minimizing contact surface area with the base of tongue and oropharyngal tissue while still being wide enough to allow adequate air flow through the posterior pharynx.

[00043] Similar to airway support assembly 100, airway support assembly 200 may optionally include an arm 212, which is similar to arm 112 appearing in Fig 1.

[00044] Fig. 3 schematically shows an airway support assembly 300 positioned in a human subject in accordance with an embodiment of the invention. Airway support assembly 300 includes an oropharyngeal airway stent 302 (hereinafter referred to as "stent"), an arm 312 and a fixation member 314.

[00045] In an embodiment of the invention, stent 302 is shaped in a helical shape, substantially as depicted. In an embodiment, the stent is formed from a wire having a diameter of 1 mm, the stent has an outer diameter of about 8 mm and an inner diameter of about 6 mm and a length of about 30 mm. The stent has a C_∑of about 0.17.

[00046] Stent 302 is attached to fixation member 314 via arm 312. When in use, fixation member 314 is connected to patient's teeth. When in use, stent 302 is positioned in a patient to prevent contact between tongue base 322 and anterior retropharynx 324, thereby maintaining patency of the oropharyngal airway.

[00047] In an embodiment of the invention, airway support system further comprises a sheath (not shown) which surrounds the stent 302 to assist in insertion of the stent into the area between tongue base 322 and anterior retropharynx 324. The sheath can be removed upon insertion of the stent. In an embodiment, the sheath holds the stent in a collapsed position and upon removal of the sheath, the stent enlarges to support the area between tongue base 322 and anterior retropharynx 324. In an embodiment, the sheath further comprises a biologically compatible lubricant to assist the patient in positioning the stent in place. In an embodiment, the sheath comprises a material which adds lubrication upon contact with the oral mucosa. [00048] Airway support assembly 100 (Fig. 1) or 200 (Fig.2) may be self inserted, simply by inserting the device at will before bedtime and removing it upon arousal. A medical doctor, nurse or technician is not required for the insertion of the airway support assembly.

[00049] Airway support assembly 100 (Fig. 1) or 200 (Fig.2) is, advantageously, a compact and portable apparatus providing an easy way to maintain an opening at the interface between the base of the tongue and the anterior retropharynx; therefore, it may be possible for the patient to employ both nose and mouth breathing when the device is in place.

[00050] The airway support assembly may be easy to use, portable, noninvasive and optionally may be anatomically adjusted to the specific patient. The airway support assembly offers a significantly simpler alternative to common OS A/snoring treatments.

[00051] In an embodiment of the invention the airway support assembly or parts thereof can be used multiple times and can be cleaned and sterilized between uses. In an embodiment of the invention, the airway support assembly or parts thereof is disposable and is intended for single use.

[00052] Example 1: Use of removable airway support system in OSA patient.

[00053] A 56 year old, overweight male who suffered from hypertension and OSA but was otherwise healthy was adverse to treatment with a CPAP apparatus was selected as a candidate for the testing of a removable airway support system.

[00054] An airway support assembly as described in figure 2 with an C_∑ of about 0.1 was prepared and inserted by the patient before falling asleep. The patient fell asleep with the airway support assembly in place and his blood oxygenation levels showed higher blood oxygenation than on previous nights of sleeping without the airway support assembly.

[00055] This example illustrates that an airway support assembly according to embodiments of the invention has been shown to be effective in maintaining patency of the oropharyngal airway in a patient suffering from sleep apnea. The assembly provided a solution to the problem of sleep apnea in a patient who was adverse to use of a CPAP device.

[00056] In the description and claims of the present application, each of the verbs, "comprise," "include" and "have," and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb. 57] Descriptions of embodiments of the invention in the present application are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments utilize only some of the features or possible combinations of the features. Variations of embodiments of the invention that are described, and embodiments of the invention comprising different combinations of features noted in the described embodiments, will occur to persons of the art. The scope of the invention is limited only by the claims.

Claims

1. A removable airway support assembly for maintaining patency of the oropharynx comprising:

an oropharyngeal airway stent; and

a fixation member for securing the stent in place in the oropharynx, wherein when the stent is inserted via the mouth into the oropharynx of a patient, the stent maintains an open airway when the patient is breathing and closes under pressure exerted when the patient swallows.

2. The assembly according to claim 1 wherein the stent has a contact index of less than 1 and greater than 0.01.

3. The assembly according to claim 2 wherein the stent has a contact index of less than 0.8 and greater than 0.01.

4. The assembly according to any one of the previous claims wherein the stent is coated with a pharmaceutical composition.

5. The assembly according to claim 4 wherein the pharmaceutical composition comprises an anesthetic.

6. The assembly according to claim 5 wherein the anesthetic is selected from the group consisting of: amylocaine, benzocaine, butacaine, butamben, chloroprocaine, dimethocaine, meprylcaine, metabutoxycaine, orthocaine, propoxycaine, procaine, proxymetacaine, risocaine, tetracaine, cyclomethycaine, hexylcaine, piperocaine, articaine, bupivacaine, levobupivacaine, ropivacaine, carticaine, cinchocaine, etidocaine, lidocaine, mepivacaine, prilocaine, and trimecaine.

7. The assembly according to either one of claims 4-6 wherein the pharmaceutical composition comprises a polymer which slowly releases the anesthetic when the stent is in contact with mucosal tissue.

8. The assembly according to any one of the previous claims further comprising an arm connecting the fixation member to the stent.

9. The assembly according to any one of the previous claims wherein the stent is configured for placement in the interface between the base of the tongue and the anterior retropharynx.

10. The assembly according to any one of the previous claims wherein the stent is configured for introduction via the mouth.

11. The assembly according to any one of the previous claims wherein the inner diameter of the stent is between 6 and 10 mm.

12. The assembly according to any one of the previous claims wherein the length of the stent is between 15 and 35 mm.

13. The assembly according to any one of the previous claims wherein the stent is coil-shaped.

14. The assembly according to any one of the previous claims wherein the stent comprises a mesh-like material.

15. The assembly according to any one of the previous claims wherein the stent is configured to be collapsed upon insertion and expanded upon placement in the interface between the base of the tongue and the anterior retropharynx.

16. The assembly according to any one of the previous claims further comprising a sheath to assist in insertion of the stent into the area between tongue base and anterior retropharynx, the sheath being removable after insertion of the stent.

17. The assembly according to claim 16 wherein the sheath maintains the stent in a collapsed configuration before and upon removal of the sheath allows for expansion of the stent.

18. The assembly according to claim 16 or 17 wherein the sheath comprises a lubricant material.

19. The assembly according to one of the previous claims wherein the fixation member is configured to be attached to the mouth of the patient.

20. The assembly according to one of the previous claims wherein the fixation member is configured to be attached to the teeth of the patient.

21. A removable airway support assembly for maintaining patency of the oropharynx comprising:

an oropharyngeal airway stent; and

a fixation member for securing the stent in place in the oropharynx, wherein the stent has a contact index of less than 1 and greater than 0.01.

22. A method for treating a sleep disorder in a patient comprising inserting via the mouth into the oropharynx patient an assembly according to any one of the previous claims.

23. The method according to claim 22 wherein the sleep disorder is snoring or obstructive sleep apnea.