Tongue Base Procedures for Obstructive Sleep Apnea

TITLE: Tongue Base Procedures for Obstructive Sleep Apnea
SOURCE: Grand Rounds Presentation, UTMB, Dept. of Otolaryngology
DATE: November 20, 2009
RESIDENT PHYSICIAN: Michael Briscoe Jr., MD
FACULTY PHYSICIAN: Vicente Resto, MD, PhD
DISCUSSANT: Vicente Resto, MD, PhD
SERIES EDITORS: Francis B. Quinn, Jr., MD
ARCHIVIST: Melinda Stoner Qui= nn, MS(ICS)

&q= uot;This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program = of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purp= ose of stimulating group discussion in a conference setting. No warranties, eit= her express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes= of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion."

Introduction

Obstructive sleep apnea affects millions of peop= le across the United St= ates. This affects not only the patient,= but also their bed partner. Affec= ts of OSA include daytime hypersomnolence, decreased productivity at work, and wi= th long-term untreated OSA, cor pulmonale and heart failure. The treatment of OSA can be purely medical, surgical, or a combination of both. Continuous positive airway pressure (CPAP) is the current therapy of choice and can relieve most causes of OSA. The surgical management = has been a bit more disappointing. The reason for this is that OSA is not a single entity that has a single surgic= al management. There are many si= tes that may cause the obstruction of OSA.&nbs= p; As clinicians, we use physical examination to attempt to diagnose the sites of obstruction, which is poor at distinguishing this. We use objective data in the form = of sleep questionnaires as well as polysomnography to diagnose OSA. Most of these patients go on to tr= ial of CPAP. For effective CPAP, the patient must wear the mask for 5 out of 7 nights for over 80% of the night. Many people cannot tol= erate the CPAP mask and seek a surgical solution. That is where the Otolaryngologist enters the management.

Diagnosis of Obstructive Sleep Apnea

History

Patients with sleep apnea often present when the= ir bed partner can no longer stand loud snoring.&= nbsp; These patients complain of excessive daytime sleepiness, and feeling like they did not sleep the night before.&= nbsp; They may complain of awakening multiple times during the night becau= se of apneas or because of the loudness of their own snoring. In the morning, they may have head= ache or dry mouth. Sometimes these patients are prone to accidents at work or while driving because they fall asleep at inappropriate times. It is important to illicit co-morbidities, use of alcohol or tobacco, and any previous trauma to the face. = Other medical problems that can contribute or exacerbate obstructive sleep apnea = are allergic rhinitis, acute rhinosinusitis, nasal polyposis, nasal tumors, and= acquired nasal deformities. The Epworth sleepiness scale is an invaluable tool for initial the assessment of obstructive sleep apnea. This survey asks the likelihood of falling asleep in 8 common situations, scaled from 0 (never) to 5 (always), and a score greater than 11 is correlated with OSA.

Physical

A complete head and neck exam is warranted in th= ese individuals because there are multiple sites that can be obstructed. The nose can be obstructed by nasal valve collapse, septal deviation, turbinate hypertrophy or nasal masses. Evaluation of the oral cavity shou= ld be done with the tongue inside of the mouth in a relaxed position. The tonsils should be graded from = 0 to 4, with zero being absent and four being kissing. Examination of the palate and uvula should also be noted. Many pa= tients with OSA will have a long, thick uvula, or redundant soft palate tissue. They may also have macroglossia, w= hich obscures the view of the palatal structures. Friedman et al developed a classification system based on modifying the Mallampati system. Friedman palate position I, you ca= n see the entire soft palate and uvula. Position II allows visualization of the uvula but not the tonsils. Position III allows visualiz= ation of the soft palate, but not the uvula, and position VI only the hard palate= is visualized. When combined with tonsil size, these form the Friedman stages I-III. In stage one, the patient has large tonsils (3 or 4), with visualization of the soft palate and uvula. Stage II has large tonsils (3 or 4= ), and visualization of only the soft or hard palate. Stage III has small tonsils (0 = 211; 2), and visualization of only the soft or hard palate. Examination of the complete pharyn= x requires either indirect mirror laryngoscopy or fiberoptic nasopharyngoscopy. Examination of the nasopharynx may reveal adenoid hypertrophy, or other occluding mass. The oropharynx may reveal lingual = tonsil hypertrophy or retroflexed epiglottis.&nbs= p; With inspiration, there may be collapse of the supraglottic structures. The Mullers maneu= ver can be performed while occluding the nose and mouth and having the patient = take an inspiration. This will all= ow the examiner to visualize pharyngeal collapse and objectively identify anterior-posterior collapse or lateral wall collapse.

Polysomnography

This is the gold standard= for diagnosis obstructive sleep apnea. This is generally and overnight, attended study performed in a sleep laboratory. EEG, pulse oximet= ry, EKG, nasal and oral airflow, respiratory effort, and leg movements are all measured during testing. Apne= as are recorded when there is cessation of nasal or oral airflow for at least 10 seconds. Hypopneas are record= ed when airflow decreases by 30% and there is an associated 4% drop in oxygen saturation. Respiratory relat= ed arousals have a 30% decrease in airflow not associated with a 4% drop in ox= ygen saturation. The apnea/hypopnea index and respiratory disturbance index as well as the minimum oxygen satur= ation are the important numbers to review in the summary. An AHI or RDI greater than five is considered mild obstructive sleep apnea.&n= bsp; When this number is greater than twenty, it is moderate, and when it= is greater than forty it is severe. Minimum oxygen saturation less than 90% is considered abnormal, and total time under 85% should be assessed to help determine the severity of s= leep apnea. After a positive PSG, = the patient should be fitted with a CPAP mask and a titration study is performe= d.

Standard Treatment for Adult Obstructive Sleep Apnea=

One of the first steps is behavioral modification. This involves s= moking cessation, avoidance of alcohol and sedatives, weight loss and modifying sl= eep position. Continuous positive airway pressure bypasses all of the levels of obstructive sleep apnea and is first-line therapy. The optim= al pressure must be achieved and the patient must wear the mask for 5 hours/ni= ght and 5 nights/week to be considered compliant. Despite all of the benefits of CPA= P, some patients cannot tolerate it. The reasons for non-compliance include excessive pressures, noise, a= ir leakage, discomfort and claustrophobia.&nb= sp; Robinson et al (2009) performed a cohort study of patients with OSA comparing health related quality of life if patients that opted for upper airway surgery to patients that tried CPAP. Found that for the patients that c= ould tolerate CPAP, their quality of life was improved and their Epworth sleepin= ess score improved. They also fou= nd that 45% of the people that tried CPAP were non-compliant or complained of = side effects. They concluded that patients with side effects or non compliant with CPAP therapy, will benefit from evaluation by an Otolaryngologist for possible surgical intervention.<= span style=3D'mso-spacerun:yes'>

In the past, surgical therapies focused on treat= ment of the soft palate. This incl= uded snare uvulectomy, uvulopalatoplasty, uvulopalatopharyngoplasty, laser-assis= ted uvuloplasty, and more recently radiofrequency ablation of the soft palate, = and tonsillar pillar implantation. The most well-known and popular of these treatments is the uvulopalatopharyngoplasty. Th= is procedure was developed to address the most probable site of obstruction and redundant tissue. It involves tonsillectomy, followed by trimming and repositioning of the anterior and posterior tonsillar pillar, and excision of the uvula with creation of a smaller neo-uvula. Kahn et al= (2009) performed a retrospective chart review of patients diagnosed with OSA undergoing UPPP over an eighteen year period. They found 63 patients that underw= ent preoperative and postoperative polysomnography. Unlike many other studies that use= a 50% reduction in AHI or AHI less than 20, they used an AHI of less than 5, whic= h is considered normal. All patien= ts underwent UPPP, and a smaller percentage underwent nasal procedures (septoplasty or turbinate reduction) or tongue somnoplasty (5%). There cure rate (AHI<5) was 23.= 8%, these patients had a lower BMI, less severe OSA, and a higher preoperative = minimum oxygen saturation. Using the standard criteria for success, they had cure rates of 50%, which correlates with other studies performed. This study and many other studies like this one can be interpreted in many ways.= One may say that UPPP is not effec= tive for obstructive sleep apnea, but this statement is not an absolute truth. Obstructive sleep apnea is caused = by obstruction at multiple sites within the upper airway, thus addressing the = site or sites of obstruction should be the goal of any therapy. While CPAP addresses all sites of obstruction, many patients require excessive pressures, or have leaks around the apparatus that preclude its use. These are the patients that may not obtain a cure with upper airway surgery, but there tolerance and compliance may be improved by undergoing surgery. This has lead pionee= rs of upper airway surgery to develop surgeries that address all of the sites of upper airway obstruction.

Tongue base procedures for Adult Obstructive Sleep A= pnea

Riley and Powell outlined phases of surgery, wit= h soft tissue work being phase I and bony work being phase II. They understood that often times, multiple procedures had to be performed to address the palatal obstruction, tongue base/retrolingual obstruction, and nasal obstruction. Phase I focuses on soft tissue wor= k, while phase II surgery is performed when soft tissue work fails. Tongue base procedures are playing= a larger role in upper airway surgery for obstructive sleep apnea because in combination with palatal procedures, they can improve outcomes from surgery. In the past, these procedures have been associated with high morbidity. Many studies have been performed to increase our knowledge of tongue base anatomy, and these procedures have be= come safer in the process.

Pertinent Tongue Base Anatomy

The base of tongue is an important structure for swallowing and speech. The tongue base provides the primary force for movem= ent of food from the oropharynx, around the epiglottis, and into the hypopharyn= x. The sulcus terminalis (a V-shaped furrow on the dorsal surface) divides the tongue into its oral and pharyngeal components. Its apex is marked by the foramen cecum. The tongue is a muscular organ covered by a thin layer of mucosa. There are two types of muscle which comprise the tongue—intri= nsic and extrinsic. Intrinsic muscles have no outside attachments whereas extrin= sic muscles have attachments to structures outside the tongue. Extrinsic tongue muscles include the genioglossus, styloglossus, chondroglossus and hyogloss= us. Embryologically, the muscles on each side of the oral tongue develop separa= tely and then fuse in the midline. This near-bloodless plane can be used for surgical access to the base of tongue. Taste papillae, serous and mucus gla= nds dot the tongue’s dorsal surface. Irregular lymphoid tissue lies at the tongue base and is referred to as the lingual tonsils.

The vallecula is the area between the tongue bas= e and the epiglottis. Irregular lym= phoid tissue lies at the base of the tongue in this trough-shaped area. These “lingual tonsils” are part of the ring of lymphoid tissues that surrounds the oropharynx. The epiglottis is composed of a long spoon-like cartilage skeleton covered with mucosa. It serves as the posterior border of the vallecula and helps to direct food bolus around the larynx and into the piriform sinuses. Its cartilaginous makeup allows it to bend with elevation= of the larynx and retrusion of the tongue base. As it bends posteriorly it cov= ers the larynx and serves to direct food around it. After the tongue relaxes it quickly springs back into its upright position.

A fibrous connective tissue structure runs betwe= en the hyoid bone anteriorly and the epiglottis posteriorly. This structure is cal= led the hyoepiglottic ligament. I= t is an important barrier to the spread of cancer from the tongue base into the = deep compartments of the larynx, preepiglottic and paraglottic spaces. It also serves as an important surg= ical plane for precise entry into the vallecula. It condenses medially to form the m= edian glossoepiglottic fold.

Surgery on the tongue base requires knowledge of= the anatomical structures that reside within the tongue base and their position. In 1997 Dr. Arthur = M. Lauretauno et al performed cadaver studies to determine the relationship of= the hypoglossal/lingual artery neurovascular bundle to the soft tissue and bony landmarks at the tongue base. These landmarks are the foramen cecum, the lateral tongue margin at the level of = the foramen cecum, the hyoid bone, and the retromolar trigone. They found that the neurovascular = bundle was 2.7 cm inferior and 1.66 cm lateral to the foramen cecum, 2.77 cm infer= ior and 1.1 cm medial to the lateral tongue margin at the level of the foramen cecum, 0.9 cm superior to the hyoid bone, and 2.18 cm medial to the mandibl= e at the level of the retromolar trigone. They concluded that the neurovascular bundle in the transverse dimen= sion lies midway between the retromolar trigone/lateral tongue border and the midline of the tongue, and that it lies fairly inferiorly, within 1.5 cm of= the hyoid bone.

Perioperative Management

There are many sequelae from untreated or inadeq= uately treated obstructive sleep apnea. There is cognitive dysfunction, higher incidence of hypertension and cardiovascular disease, risk of pulmonary hypertension, and increased incid= ence of stroke. Many of these pati= ents will have co-morbidities that will need to be addressed prior to surgery. While most patients undergo surgery because of CPAP intolerance, it is imperative that they use their CPAP for = at least two weeks prior to and after surgery. This is so they do not accumulate a sleep debt. Hypertension shou= ld be treated aggressively in the perioperative period. After surgery, admission with pulse oximetry and pain management with narcotics is required. Patients need to demonstrate the a= bility to tolerate a liquid diet, have adequate pain control, and have a safe airw= ay prior to discharge.

Overview of Soft Tissue Tongue Base Procedures

Radiofrequency tongue base ablation ̵= 1; a two-pronged insulated probe is inserted into the tongue base around the lev= el of the foramen cecum. Radiofrequency is delivered at a frequency of 465 KHz to ablate the tongue tissue, and cause scar contracture, thus reducing the tongue volume.= This can be done in the office und= er local anesthesia, or can be performed in the operating room under general anesthesia. The best results = have been seen when delivering a total of 12kJ in 8-12 locations, over a four we= ek period. This may also be done= as a onetime procedure, but there is more risk of mucosal ulceration.

Lingual tonsillectomy= – this can be performed with either microdebrider or coblation. This should be done under visualiz= ation with telescope, and care should be taken to avoid damage to the hypoglossal nerve, lingual artery neurovascular bundle.

Midline= Glossectomy – Enlarges the retrolingual airway by reducing the base of tongue by approximately 2.5 x 5 cm through an intraoral approach. Lingual tonsillectomy, epiglottect= omy, and aryepiglottic fold reduction may be performed at the same setting. There usually is significant airway edema, necessitating tracheotomy.

Submuco= sal minimally invasive lingual excision – This procedure is performed under general anesthesia. The tongue base is infiltrated with 25 ml of saline, and the course of the ling= ual arteries is marked using a Doppler for guidance. An incision is made in the midline= of the tongue, and the coblator is used to ablate tissue at the tongue base. Ablation is performed medially to = the marked lingual arteries. The incision is left open, and heals by secondary intention. This allows for a greater degree of tongue base reduction than radiofrequency tongue base ablation, with less morbidity than the midline glossectomy.

Mandibular Tongue Base Procedures

Geniotu= bercle advancement – This opens the retrolingual space by pulling the to= ngue base forward. This is perform= ed through a gingivobuccal incision. The midline of the mandible in the lingual cortex is the site of insertion of the genioglossus muscle. Osteotomies are made to mobilize the genial tubercle, with care not = to cut the tooth roots. The ging= ival cortex is then drilled away, and the segment is advanced and rotated. It is secured in place with 1 or 2= screws, and the wound is closed.

Repose = system – An intraoral incision is made at the mandibular frenulum, a titanium screw is placed at the lingual cortex of the geniotubercle. A permanent suture is then passed = through the paramedian tongue bilaterally to the base of tongue, and back to the titanium screw in the lingual cortex. Tightening the screw pulls the tongue base anteriorly.

Hyoid suspension - horizontal cervical incision is made over the hyoid bone, = and dissection is carried down to the suprahyoid musculature. The hyoid bone is then advanced ov= er the thyroid ala, and secured with permanent suture.

Maxillomandibular Advancement

This procedure requires extensive preoperative measurements and planning in order to achieve surgical success. It is usually performed after the = above surgeries have failed to improve obstructive sleep apnea. Cephalometrics can assist in evalu= ating the hypopharyngeal airway. Th= is is an x-ray taken with the patient in profile, sagittal orientation. The important landmarks are the se= lla (S), nasion (N), anterior nasal spine (ANS), gnathion (Gn), gonion (Go), A = point (A), B point (B), posterior airway space (PAS), and the hyoid (H). The normal angle for SNA is 82, an= d the normal for SNB is 80. Splints= need to be made with preoperative occlusion, and intermediate occlusion. Advancement is performed by at lea= st 10 mm for optimal results. A Lef= ort I osteotomy is performed with plating of the fractured segment after appropri= ate advancement. Bone grafts may = need to be placed. The bilateral sagittal split osteotomy is then performed. The patient is then kept in maxill= omandibular fixation.

Complications

Radiofrequency ablation is the safest method of addressing the base of tongue with a low rate of complications (3.4%). These range from mucosal ulceratio= n, to superficial infection, and transient parasthesia of the hypoglossal nerve.<= span style=3D'mso-spacerun:yes'> The midline glossectomy and smile procedures allow for more resection, but also pose a greater risk to the hypoglossal nerve/lingual artery neurovascular bundle. There can be significant bleeding requiring neck exploration with ligation of vessels. There is also risk for airway edem= a, hematoma, abscess formation, and permanent hypoglossal injury. The Repose system and geniotubercle advancement, can cause patient discomfort if there is excess tension, and c= an cause mild aspiration that is temporary.&n= bsp; MMA may cause permanent parasthesias of the mental, infraorbital, or inferior alveolar nerve because of stretching during advancement. This has been shown to occur in up= to 89% of patients, in addition, many patients have TMJ complaints. MMA also may drastically alter the person’s facial appearance (89%).&nb= sp; These are all things that must be discussed at the time of preoperat= ive evaluation.

Future Directions

Sleep e= ndoscopy – drug induced sleep endoscopy has been performed by infusing propofol until the patient was deeply sedated, but arousable to loud stimuli. An assessment of the patient’= ;s airway is then performed to determine the sites of obstruction. This is relatively new, and has no= t been performed in the US<= /st1:place> at many centers, thus more studies are needed for a standardized protocol.<= /p>

Sleep M= RI – real time MRI image while the patient is asleep. This also is in early stages of research, but may help with determining the site of obstruction in the futu= re.

Bariatr= ic surgery - may play a role in patients with morbid obesity and severe obstructive sleep apnea. More studies

Conclusions

Obstructive sleep apnea affects millions of Americans. First line treatme= nt includes behavioral modifications such as avoidance of alcohol and sedative= s, discontinuing smoking, and weight loss, but the mainstay of therapy is continuous positive airway pressure. Compliance is defined as wearing the CPAP apparatus for five nights = per week, and at least four to five hours per night. Because of excessive pressure, or = many other side effects, there are patients that cannot tolerate CPAP. Titration studies can be performed= to decrease the amount of pressure given, but some patients ultimately want a surgical solution for their sleep apnea.&n= bsp; This disease is generally characterized by obstruction at multiple sites, and one surgery is not effective for all patients with sleep apnea.<= span style=3D'mso-spacerun:yes'> Because of this, many patients req= uire multilevel upper airway surgery. Tongue base procedures are relatively novel, and knowledge of the anatomy is crucial to avoid injury to the hypoglossal nerve/lingual artery neurovascular bundle. These procedures should be offered to appropriately selected patients.

Discussion by Dr. Vicente Resto, of Dr. Briscoe’s Grand Rounds presentation = on OSA 11/20/2009

That was a great comprehensive review, Dr. Briscoe, about not only the definitions and diagnosis of sleep apnea but also the surgical interventions.=

I think your talk highlights w= hat I think is the greatest obstacle to understanding the effectiveness of the procedures in the management of this disease. And that is that the definition is= so varied in terms of describing success or failure.

As reported in the first study= that you reviewed where the group looked at improvement by using the Epworth sco= re and as well as polysomnography and also demonstrated that although both of those measures improved greatly the Glasgow index failed to improve and that has the important component of a quality of live for the patient.

So it remains to be seen how m= any of these interventions really drive patient improvement. I think it’s fair to say that unless we achieve an RDI of less than 5 it’s really up for debate whe= ther the things we do are really worthwhile or not or are we just simply impacti= ng the patient by allowing them to better tolerate CPAP.

Alternatively, we know that th= ere are physiological consequences to sleep apnea but none of these studies have looked that as an endpoint. Is there benefit from reducing the RDI by 50% yet still remain within the abno= rmal range as pertains to these comorbid scores? Does that translate into a physiol= ogic improvement by way of preventing hypertension and perhaps some of the other cardiopulmonary issues?

As it stands today, one has to= be cautious about the level of morbidity that one is willing to engage in with= our patients, especially in a setting where we know that CPAP is truly curative= .

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