US20080078411A1 - Tongue implant for sleep apnea - Google Patents

Abstract

A patient's obstructive sleep apnea is treated by identifying a patient with sleep apnea attributable at least in part to movement of a base of a tongue of said patient toward a pharyngeal wall of said patient. The method includes identifying a region in the tongue extending from a mandibular-geniohyoid interface to the base of the tongue and stiffening a tissue of the tongue throughout the identified region.

Description

IBACKGROUND OF THE INVENTION
• 1. Field of the Invention
• This invention pertains to a method for treating a condition of an upper airway of a patient. More particularly, this invention is directed to a method for treating obstructive sleep apnea by stiffening a tongue of a patient.
• 2. Description of the Prior Art
• Upper airway conditions such as obstructive sleep apnea (“OSA”) and snoring have received a great deal of attention. These conditions have recognized sociological and health implications for both the patient and the patient's bed partner.
• Numerous attempts have been made towards treating OSA and snoring. These include placing implants in either the tissue of the soft palate or the pharyngeal airway as disclosed in commonly assigned U.S. Pat. No. 6,250,307 to Conrad et al. dated Jun. 26, 2003, U.S. Pat. No. 6,523,542 to Metzger et al. dated Feb. 25, 2003 and U.S. Pat. No. 6,431,174 to Knudson et al. dated Aug. 13, 2002. Further, U.S. Pat. No. 6,601,584 to Knudson et al. dated Aug. 5, 2003 teaches a contracting implant for placement in the soft palate of the patient.
• Another prior art technique for treating OSA or snoring is disclosed in U.S. Pat. No. 5,988,171 to Sohn et al. dated Nov. 23, 1999. In the '171 patent, a cord (e.g., a suture material) (element 32 in FIG. 6 of the '171 patent) is placed surrounding a base of the tongue and secured to the jaw by reason at an attachment member (element 20 in FIG. 6 of the '171 patent). In the method of the '171 patent, the member 32 can be shortened to draw the base of the tongue toward the jaw and thereby move the tissue of the base of the tongue away from the opposing tissue of the pharyngeal airway. However, this procedure is often uncomfortable. This procedure, referred to as tongue suspension, is also described in Miller et al., “Role of the tongue base suspension suture with The Repose System bone screw in the multilevel surgical management of obstructive sleep apnea”,Otolaryngol. Head Neck Surg., Vol. 126, pp. 392-398 (2002).
• Another technique includes debulking tissue by applying radio frequency ablation to either the tongue base or of the soft palate to debulk the tissue of the tongue or palate, respectively. This technique is illustrated in U.S. Pat. No. 5,843,021 to Edwards et al. dated Dec. 1, 1998. RF tongue base reduction procedures are described in Powell et al., “Radiofrequency tongue base reduction in sleep-disordered breathing: A pilot study”,Otolaryngol. Head Neck Surg., Vol. 120, pp. 656-664. (1999) and Powell et al., “Radiofrequency Volumetric Reduction of the Tongue—A Porcine Pilot Study for the Treatment of Obstructive Sleep Apnea Syndrome”,Chest, Vol. 111, pp. 1348-1355 (1997).
• A surgical hyoid expansion to treat OSA is disclosed in U.S. Pat. No. 6,161,541 to Woodson dated Dec. 19, 2000. Other tongue treatments for OSA include stimulation of the hypoglossal nerve. This procedure is described in Eisle et al., “Direct Hypoglossal Nerve Stimulation in Obstructive Sleep Apnea”,Arch. Otolaryngol. Head Neck Surg., Vol. 123, pp. 57-61 (1997).
• Commonly assigned U.S. patent applications Publication Nos. US 2005/0092332 A1 and US 2005/0092334 A1 (both published May 5, 2005) describe tongue-based treatments to treat obstructive sleep apnea. U.S. patent application Ser. Nos. 11/107,160 and 11/107,161 (both filed Apr. 15, 2005 and assigned to the assignee of the present invention) describe various implants for a tongue to treat obstructive sleep apnea.
• European Patent EP 1,039,859 B1 granted Dec. 3, 2003 describes a brace placed in the tongue. German Patent No. 19 920 114 describes struts in pharyngeal wall. U.S. patent applications Publication Nos. US 2005/0126563 A1 published Jun. 16, 2005 and US 2005/0199248 A1 published Sep. 15, 2005 describe stents in an airway. U.S. patent applications Publication Nos. US 2004/0139975 published Jul. 22, 2004 and US 2004/0149290 published Aug. 5, 2005 (both assigned to Apneon Inc.) describe struts or magnets in the tongue.
IISUMMARY OF THE INVENTION
• According to a preferred embodiment, obstructive sleep apnea of a patient is treated by identifying a patient with sleep apnea attributable at least in part to movement of a base of a tongue of said patient toward a pharyngeal wall of said patient. The method includes identifying a region in the tongue extending from a mandibular-geniohyoid interface to the base of the tongue and stiffening a tissue of the tongue throughout the identified region.
IIIBRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a side sectional schematic view of an upper airway of a patient and illustrating various anatomical features;
• FIG. 2 is the view ofFIG. 1 showing an implant of the present invention placed within the tongue according to a treatment method of the present invention;
• FIG. 3 is a side elevation view of the implant ofFIG. 1;
• FIG. 4 is a perspective view of the implant ofFIG. 3;
• FIG. 5 is the view ofFIG. 1 showing an incision formation tool placed within the tongue;
• FIG. 6 is the view ofFIG. 5 with the incision formation tool actuated to an open position to form a pocket for receiving the implant ofFIG. 3;
• FIG. 6A is a view taken alongline6A-6A inFIG. 6;
• FIG. 7 is the implant ofFIG. 3 disposed on an implant insertion tool before final deployment;
• FIG. 8 is a view taken along line8-8 ofFIG. 7;
• FIG. 9 is the view ofFIG. 7 with the implant insertion tool moved to an open position to fully place the implant within a pocket formed within the tongue;
• FIG. 10 is the view taken alone line10-10 ofFIG. 9;
• FIG. 11 is the top plan view of a tongue showing positioning of two implants within the tongue;
• FIG. 12 is a view taken along line12-12 ofFIG. 11;
• FIG. 13 is a top plan view of a tongue showing an entire target region being stiffened;
• FIG. 14 is the view ofFIG. 1 showing the entire target region ofFIG. 13;
• FIG. 15 is the view ofFIG. 2 showing an alternative embodiment of an implant according to the present invention showing multiple implants in the tongue;
• FIG. 16 is a perspective view of a tubular implant used in the embodiment ofFIG. 15;
• FIG. 16A is an end elevation view of the implant ofFIG. 16;
• FIG. 17 is a top plant view of a tongue with implants ofFIG. 16 arranged extending along an anterior-posterior axis of the tongue; and
• FIG. 18 is the view ofFIG. 17 with the implants disposed in the target region ofFIG. 13.
IVDESCRIPTION OF THE PREFERRED EMBODIMENT
• With reference now to the various drawing figures in which identical elements are numbered identically throughout, a description of the preferred embodiment of the present invention will now be provided.
• FIG. 1 is a schematic representation of an upper airway of a patient.FIG. 1 shows the tongue T with a tongue base TB opposing a pharyngeal wall PW. The hard palate HP and soft palate SP reside over the top of tongue T with the soft palate SP extending rearward to a trailing end TE between the tongue base TB and the pharyngeal wall PW.
• A hyoid bone HB resides near the bottom of the tongue near an epiglottis E. A mandible or jaw bone JB is at the front of the tongue T. The geniohyoid muscle GH extends between the jaw bone JB and the hyoid bone HB at the bottom of the tongue T. The lines A ofFIG. 1 illustrate the direction of muscle fibers in the geniohyoid muscle GH. The genioglossus muscle GG resides above the geniohyoid muscle GH. The genioglossus muscle GG has muscle fibers B which extend from the jaw bone JB and curve to radiate toward the surface of the tongue T.
• When reclining during sleep, the tongue base TB may, in response to gravity or airflow, drop down in closer approximation to the pharyngeal wall PW. During sleep, the muscles of the tongue T (principally the genioglossus muscle GG) can stretch permitting the tongue T to fall back toward the pharyngeal wall PW.
• The present invention is directed towards method and apparatus for stiffening the muscles of the tongue T in a manner to preclude the tongue T from falling toward the pharyngeal wall PW while avoiding interference with normal functions of the tongue T during speech and eating.
• FIG. 2 illustrates the present invention as animplant10 placed within the interior of the tongue T. Theimplant10 has aproximal end12 and adistal end14. In a preferred embodiment, theimplant10 is a substantially planar sheet formed as a generally conical envelope best illustrated inFIG. 4. Thedistal end14 is the base of a cone with opposing edges of the base being stitched or otherwise bonded together so that the interior of theimplant10 is accessible only through theproximal end12. Theimplant10 is a flat sheet with opposing surfaces of the cone compressed against one another.
• Theimplant10 is sized to be received within the tongue T with theproximal end12 positioned in a region of the tongue T adjacent the interface of the jaw JB and geniohyoid muscle GH. The height of the proximal end12 (illustrated as H_PinFIG. 3) is sized for theproximal end12 to be received within the tongue T at the juncture of the jaw bone JB and the geniohyoid muscle GH. Theimplant10 is further sized to have a length L for thedistal end14 to be positioned adjacent the tongue base TB in close proximity to the tongue base TB when theproximal end12 is positioned in a region of the tongue T adjacent the interface of the jaw JB and geniohyoid muscle GH. The height of the distal end14 (illustrated as H_DinFIG. 3) is sized for thedistal end14 to extend within the tongue base TB substantially covering a region of the tongue base TB opposing the pharyngeal wall PW between the epiglottis E and the trailing end TE of the soft palate TB. By way of non-limiting example, representative dimensions for H_P, H_Dand L are 1.0 centimeter, 2.5 centimeters and 4 centimeters, respectively. The fibrils of the material ofimplant10 are about 20 microns to 100 microns in diameter. Depending on the braid or weave and the fibril diameter, the thickness of a sheet of the material may range from 50 to 500 microns. A double thickness TH (FIG. 12) (which is transverse to the anterior-posterior axis of the tongue T following implantation) would be about 100 to 1000 microns.
• The material of theimplant10 is selected to produce a fibrotic response from the tissue of the tongue T following implantation of theimplant10 within the tongue T. The specific materials and construction may be varied to alter the degree of fibrotic response resulting from such implantation. By way of non-limiting example, the material of theimplant10 may be a knit or woven polyester or polypropylene material known to result in a fibrosis formation following implantation.
• FIGS. 5-10 illustrate a technique and tools for placement of theimplant10 within the tongue. InFIG. 5, atool20 is shown for forming an incision in the tongue T sized to receive theimplant10. Thetool20 includes a curved handle22 and ascissors end24. The scissors end24 is hinged to the handle athinge point26 and includes a pair ofscissor blades28,30 (shown inFIG. 6). Thetips29,31 of theblades30,28 are sharp to permit insertion of thetips29,31 through tissue into the tongue T. Further, theedges27,33 of theblades28,30 are sharp to permit slicing action of thescissor blades28,30 through tissue.
• In use, theblades28,30 are collapsed so that they are in parallel alignment as shown inFIG. 5. Thetips31,29 are passed through the patient's open mouth and are inserted into the tongue T at the front lower extremity of the tongue T just behind the jaw bone JB. Insertion is first made by urging thetips29,31 downwardly into the region of interface between the geniohyoid muscle GH and the jaw bone JB and then curving the direction of travel upwardly to urge thetips29,31 toward the tongue base TB.
• When thetool20 is in the position ofFIG. 5, thescissor blades28,30 are opened as shown inFIG. 6 to cut a pocket for receiving animplant10. Thetool20 is then removed. The arcuate nature of the handle22 permits formation of an incision pocket extending from the geniohyoid muscle GH at the jaw JB toward the tongue base TB between the epiglottis E and the trailing end TE of the soft palate SP.
• Following formation of the pocket, aninsertion tool40 is provided as illustrated inFIG. 7.Insertion tool40 is similar in construction to theincision formation tool20. It includes acurved handle42 andscissor action blades44,46. Unlikeblades28,30, theblades44,46 do not have knife edges in order to avoid damage to theimplant10.
• With theblades44,46 in parallel alignment as shown inFIGS. 7 and 8, the tips of theblades44,46 are inserted into the interior of theimplant10 through theproximal end12. Theimplant10 can then be folded surrounding theblades44,46 into a compact configuration surrounding theblades44,46 as shown inFIGS. 7 and 8. Thetool40 carrying theimplant10 is placed into the incision pocket formed bytool20. Such positioning is shown inFIG. 7. After such positioning, theblades44,46 are actuated to an open position shown inFIG. 9 urging theimplant10 to its expanded state. Theblades44,46 can then be returned to their collapsed state and removed from the tongue T leaving theimplant10 in desired position within the tongue T.
• As mentioned, it is desired that theproximal end12 of theimplant10 be as positioned as close as possible to the jaw bone JB in the region of the geniohyoid muscle GH. If necessary, the surgeon can form additional incisions through the tongue T to pull theproximal end12 into the geniohyoid muscle GH in close proximity to the jaw bone JB.
• FIG. 11 shows twoimplants10,10′ positioned within the tongue T in the manner such as that previously described. Ideally, theimplants10,10′ extend along the anterior posterior A-P axis. The proximal ends12,12′ are positioned in close approximation to the anterior-posterior axis A-P. Preferably, theimplants10,10′ do not extend straight back. Instead, they are angled outwardly toward the sides of the tongue T. As a result, the distal ends14,14′ are spaced apart at opposite lateral extremities of the tongue base TB.
• Following implantation, a fibrotic capsule FC forms around the material of theimplant10. The capsule FC is illustrated inFIG. 12. The fibrotic capsule FC adds stiffness to the tissue of the tongue T.
• At the juncture of the geniohyoid muscle GH and the jaw bone JB (referred to herein as the “mandibular-geniohyoid interface”, muscle fibers of the tongue are tendon-like. By “tendon-like”, it is meant the muscle fibers are less susceptible to stretching than the remainder of the length of the fibers. Since the fibrotic capsule FC and theproximal end12 of theimplant10 originate in this region, a substantially non-stretchable region is formed in the tongue T by reason of the fibrotic capsule FC and theimplant10.
• In the absence of animplant10, substantially the entire length of muscle fibers from the jaw bone JB to the tongue base TB can stretch during sleep resulting in the tongue base TB falling against the soft palate SP or pharyngeal wall PW during sleep. With theimplant10 extending from the jaw bone JB to the tongue base TB, the muscle fibers in contact with theimplant10 and resulting fibrotic capsule FC are much less susceptible to stretching.
• Use of twoimplants10,10′ (FIG. 11) forms two such non-stretchable planes within the tongue T. The placement ofFIG. 11 ties the tongue base TB to the jaw bone JB with the lateral extremities of the tongue based TB being treated to resist stretching. If desired, a third implant could be placed along the anterior-posterior axis A-P to further resist tongue stretching.
• FIGS. 13 and 14 illustrate extreme treatments where the entire volume of the tongue from the mandibular-geniohyoid interface to the base of the tongue is stiffened. This volume V is illustrated inFIGS. 13 and 14 as a shaded area. The volume is defined as a generally conical volume having an apex at the mandibular-geniohyoid interface. The base of the conical volume is at the tongue base TB near the surface of the tongue and covering the portion of the tongue base TB opposing the pharyngeal wall PW between the epiglottis E and the training end TE of the soft palate SP. The volume V extends between the lateral extremities of the tongue base TB.
• Treatment of the entire volume can be accomplished bymultiple implants10 placed as described above. Alternatively, the volume V can be injected with any fibrosis-inducing agent (e.g., microbeads) throughout the volume V.
• Ideally, theimplant10 will contract and expand with the muscle as it heals. Otherwise, a capsule surrounding theimplant10 will form as muscle slides over theimplant10. This property is enabled by a combination of factors: the restoring force of theimplant10, the friction against the tissue and attachments if any at either end. The mesh material of theimplant10 aids in achieving these objectives. The goal is to have an appropriate amount of spring tension/expansion and wall friction/in-growth such that theimplant10 contracts and expands with tissue. It is desirable to avoid an implant so stiff as to overly contract the muscle. This may cause the distal end of the implant to slide more proximal. As the scar forms and contracts, the implant contracts more permanently with the scar. This suggests the restoring force decreases over time. Biodegradable fibers suitable for this purpose or biodegradable coatings on the fibers themselves (which adhere the fibers together) may be used. The elastic properties of the implant should are approximately between 5 kPa to 50 kPa. The frictional force should be approximately 2N to 4 N. The patient's physiology and the size of the implant affect the range for these values.
• FIGS. 15-18 illustrate an alternative embodiment in which the target area or volume of the tongue is stiffened by placement of a plurality oftubular implants10″. Onesuch implant10″ is separately shown inFIGS. 16 and 16A. In a representative embodiment, theimplant10″ is tube of polyester or other material selected to induce fibrosis following implantation in the tongue T. Theimplant10″ has a length L′ of 3-5 centimeters, an outside diameter D_Oof about 1 mm to 3 mm and an inside diameter D_Iresulting from a wall thickness of about 50 to 500 microns.Implants10″ for a single patient need not all be the same length L′. More interior implantedtubes10″ may be shorter so that proximal ends12″ do not impinge upon one another whenmultiple implants10″ are used (as will be described).
• Theimplant10″ may be placed with aproximal end12″ at the mandibular-geniohyoid interface and with adistal end14″ at the tongue base TB.FIG. 15 shows threesuch implants10″ disposed in a verticalplanar array16″ substantially filling the plane ofimplant10 ofFIG. 2. A singlesuch array16″ may be positioned in line with the anterior posterior axis A-P (as shown inFIG. 17) or multiplesuch arrays16″ may be positioned similar to the positioning ofimplants10 inFIG. 11 (as illustrated inFIG. 18). Use oftubular implant10″ permits a more uniform distribution of implants in the target volume V and creation of a filled target volume of more conical shape.
• The insertion tool for the tube shapedimplants10″ may be much like the insertion tool described in U.S. patent application Publication No. 2005/0154412 A1 (incorporated herein by reference) which describes a tool for placing a solid braided implant such as that marketed by assignee of the present application (Restore Medical Inc., St. Paul, Minn., USA) under the trademark “Pillar”. The tool may be modified to replace the needle of the tool with a rod received within theimplant10″ through theproximal end12″. The rod may extend to thedistal tip14″ of theimplant10″. Retracting the rod leaves theimplant10″ in desired position in the tongue T.
• In the foregoing example, no stiffening treatment is made in the tongue T in the upper region of the tongue T. Generally defined herein as the region of the tongue T above and forward of a line from the jaw bone JD to the trailing end of the hard palate HP, this region of the tongue T is active in speech and swallowing. Since no treatment is made in this region, these functions are not impaired.
• It has been shown how the present invention has been obtained in a preferred embodiment. Modifications and equivalents of the disclosed concepts are intended to be included within the scope of the claims which are appended hereto.

Claims (9)

1. A method for treating obstructive sleep apnea comprising:

identifying a patient with sleep apnea attributable at least in part to movement of a base of a tongue of said patient toward a pharyngeal wall of said patient;

identifying a region in the tongue extending from a mandibular-geniohyoid interface to the base of the tongue;

stiffening a tissue of the tongue throughout the identified region.

2. A method according toclaim 1 wherein the identified region includes an area of the base of the tongue opposing the pharyngeal wall between an epiglottis and a trailing end of a soft palate.

3. A method according toclaim 1 wherein the identified region includes an area of the base of the tongue between lateral extremities of the base of the tongue.

4. A method according toclaim 1 wherein said stiffening includes placing an implant of fibrosis-inducing material within the tongue with the implant extending throughout said region with the material selected to induce formation of fibrosis along said region.

5. A method according toclaim 4 wherein said implant is sized for said region to extend substantially between an epiglottis and a soft palate of the patient at the base of the tongue.

6. A method according toclaim 5 wherein said implant is a substantially planar sheet placed in the tongue with a narrow dimension extending transverse to the tongue and having a proximal end within said region at said mandibular-geniohyoid interface and with a distal end within the tongue at the base and extending between the epiglottis and the soft palate.

7. A method according toFIG. 4 wherein said implant is a tubular material selected to induce fibrosis formation and with a proximal end at said mandibular-geniohyoid interface and with a distal end at said base of the tongue.

8. A method according toclaim 7 wherein said region includes an area of the base of the tongue between lateral extremities of the base of the tongue and said method includes placing multiples of said implants in a volume of said tongue within said region.

9. A method according toclaim 1 according toclaim 4 wherein said material is selected for said implant to contract and expand with the tongue as the tongue heals.

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