1

Introduction

Obstructive sleep apnea syndrome (OSA) results from a complex scenario initiated with airway collapse and obstruction, loss of compensatory wake and sleep reflexes, increased ventilatory effort, arousal, hypoventilation, and asphyxia during sleep. In adults, a structurally small upper airway may be a primary contributing factor. Enlarging this airway may prevent the cascade into sleep apnea and snoring. The small upper airway in adults may result from an abnormal craniofacial structure, excessive soft tissues, and obesity. Abnormalities may involve multiple upper airway segments, including the tongue base. Altering or preventing tongue base collapse may reduce both palatal and tongue base obstruction and improve OSA. Multiple procedures have been described with varying success and morbidity. For surgeons, the dilemma has been to adequately treat these observed sites of obstruction with the least morbidity. The procedure of tongue base suspension is an option to treat lower pharyngeal obstruction and reduce morbidity compared with alternative procedures. In a systematic review of 10 studies (n = 300) with suture tongue suspension and uvulopalatopharyngoplasty (UPPP), Bostanci and Turhan demonstrated a variable success rate from 20% to 90% (average 70%) with Apnea/Hypopnea Index and sleepiness improved in all studies.

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Indications and Rationale

No precise indications for tongue suspension are published. Based on anatomy and physiology, a wide variety of patients may benefit from tongue stabilization. Indications would include all patients who are poor candidates for isolated UPPP, such as Friedman stage II and III.

The tongue in humans is unique in being both an oral and a pharyngeal structure. As such, it is important not in just speech, mastication, and swallowing, but also is critical in controlling the pharyngeal and oral airway. The anterior wall of the lower pharynx is the posterior tongue whose position stabilizes the hypopharynx, the lateral pharyngeal walls, and the palate. Reducing tongue collapse during sleep stabilizes the airway. This effect may be mediated by altering the oropalatal airway, the retroglossal airway, and for some procedures the major effect is on the retropalatal airway and lateral pharyngeal walls. Traditional techniques include skeletal mandibular osteotomies and tissue reduction with glossectomy or lingual tonsilectomy.

The primary goal of airway surgery is to prevent both dynamic (during inspiration) and passive (during expiration) airway collapse during sleep. Collapse occurs both due to a structurally small upper airway (i.e. an anatomically vulnerable airway) and abnormalities of collapsing and dilating forces. Obstruction occurs when dilating forces cannot balance the collapsing forces needed for a given anatomic structure. Theoretically, surgery may prevent collapse by increasing airway size, increasing inspiratory dilating forces, or decreasing inspiratory or expiratory collapsing forces.

Tongue suspension sutures are unable to directly increase airway volume or significantly alter a structurally small upper airway. Tongue suspension sutures, however, may alter the balances between dilating and collapsing forces on the tongue. Preventing collapse may not only reduce the likelihood of direct airway obstruction by tongue tissues, but it may (more importantly) have significant indirect effects because a partial reduction in collapse may reduce airway resistance, reduce fluctuations in CO ₂ , and ultimately help reduce abnormalities in respiratory drive that result in abnormally high negative inspiratory pressures which, in turn, contribute to snoring and abnormal airway collapse. Understanding such indirect mechanisms is important because minor changes in airway collapse can have major effects on whether the upper airway obstructs.

The tongue suspension procedure was conceived as a means of providing an extraluminal dilating force to the lower pharyngeal airway. Tongue suspension may be performed with multiple techniques, but all are similar in having the goal of passing a submucosal suture into the posterior midline tongue. The suture prevents passive collapse while not interfering with anterior and superior tongue movements that are involved with swallowing and speech.

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Patient Selection

Selection is based on data from a small number of case series. Contraindications to this procedure include poor general medical health or isolated upper airway obstruction in the retropalatal region with Friedman stage I. In addition, relative contraindications include severe macroglossia (where a small amount of dilating force will not be of benefit) or there is abnormal mandible bone. Patients with severe obstruction caused by excessive tissue volume of the tongue or lateral walls likely will not respond.

Patients who have significant macroglossia or marked lateral wall collapse should not generally be considered for tongue suspension because these patients often need procedures where airway volume needs to be increased. Tongue suspension has not been demonstrated to increase resting airway volume. Those patients who are best have smaller tongues. Best findings include those patients with modified Malampati I and II (Friedman tongue position I or II) with a favorable relationship of the hyoid bone (mandibular plane to hyoid distance = MPH short). Modified Malampati III (Friedman tongue position III) may be favorable in some cases if the finding is not resulting from excessive tongue tissue volume. Patients who have modified Malampati IV (Friedman tongue IV) or those with massive volumetric tongues (where the tongue dorsum is well above the occlusal plane are unlikely to benefit. Patients where there is no oral or oropalate volume do poorly with the procedure.

When patients are examined endoscopically, the best patients for suspension are those who have good to excellent retroglossal airway volumes while sitting but collapse at the retroglossal airway going from the sitting to the supine position.