Transpalatal advancement pharyngoplasty

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Chapter 36 Transpalatal advancement pharyngoplasty

1 INTRODUCTION

The ultimate goal of surgical treatment for obstructive sleep apnea (OSA) is to improve symptoms and eliminate disease morbidity and mortality. This is accomplished by altering airway sizecompliance and shape. Successful surgery eliminates collapseairflow limitation and airway obstruction during sleep. The precise features of successful versus unsuccessful surgery remain poorly understood.

The retropalatal airway segment is a major contributor to airway obstruction in sleep apnea. Although uvulopala-topharyngoplasty (UPPP)as described by Fujitaremains the most common OSA surgeryit suffers from technical failures including inexact patient selectionincorrect and flawed techniqueand external factors such as infection. To address palatal failurea different approach is required.

Transpalatal advancement pharyngoplasty alters the retropalatal airway by advancing the palate forward. Hard palate is excised and a palatal advancement flap is created. It does not require excision of the soft palate. The palate is pulled forward and superior which conceptually is similar to maxillary advancement.

The procedure used alone or in combination with other soft tissue surgeries is indicated for sleep apnea patients having narrowing in the retropalatal airway. It is particularly useful when there is narrowing of the pharyngeal isthmus proximal to the point of palatal excision using traditional UPPP techniques. A transpalatal approach and advancement is also useful for obstructions in the nasopharynx (such as enlarged adenoids) that cannot be accessed through traditional techniques due to the difficult OSA anatomy.

2 SURGICAL TECHNIQUE

2.1 EVALUATION

Preoperativelynasopharyngeal endoscopy is currently the primary method of airway evaluation and is performed in both a sitting and supine body position. Features evaluated include sizeshapeareas of collapseand pharyngeal swallow. During endoscopyclose attention is focused on the size and the shape of the proximal pharyngeal isthmus. Narrowing of the airway proximal to this point of estimated excision of traditional UPPP is an indication for primary transpalatal advancement pharyngoplasty. The shape of the pharyngeal isthmus indicates whether narrowing is from anterior–posterior compression (transversely shaped) or from collapse of the lateral walls (sagittally shaped). The locations of the levator muscle and palatopharyngeal sphincter are identified by visualizing the anterior fold of the torus tubarus (torus levatorius) which leads to the position of the levator muscle in the soft palate (Fig. 36.1). A narrow anterior to posterior airway at this level indicates retromaxillary airway narrowing. Such an abnormality cannot be addressed by traditional palatopharyngoplasty without aggressive excision of the levator muscle.

The retropalatal and retromaxillary airway is a fundamental abnormality of adults with sleep apnea. Normal upper airway shape and size must be learnedas well as patterns of stenosis and scarring of the retropalatal segment following palatal or tonsil surgeries. Swallow is also evaluated while performing endoscopy with specific attention to lateral wall motion. Impaired lateral wall motion may increase the risk of swallow dysfunction with any palatal surgery. Patients at high risk of pharyngeal swallowing dysfunction (abnormal endoscopic examsymptomatic dysphagiavelopharyngeal insufficiencypresbyesophagussevere reflux and anterior cervical spine surgery) need further swallow evaluation. Fortunatelyeven in patients who have had prior UPPPpalatal and maxillary advancement are not usually associated with worsening of dysphagia.

Evaluation of the oropalatal airway is also needed. Since the palate relative to the tongue base is pulled forward a small oropalatal airway space may be worsened. This requires additional surgery even if the pharyngeal retroglossal airway space is not severely abnormal. The oropalatal airway is assessed initially with routine oral examination. A modified Malampatti 1 or 2 position indicates excellent oropalatal airway space. Modified Malampatti 3 and 4 have a compromised oropalatal airway. Those patients with very small oral airways who are primarily mouth breathers need this segment treated prior to palatal surgery.

Contraindications for the procedure include partial or complete cleft palateswallowing dysfunction with poor lateral wall movementa large torus palatini (requiring removal prior to advancement)velopharyngeal insufficiencyobligate mouth breathers (may worsen oral breathing)those who have severe gagor patients unable to accept the recovery from a complication. Maxillary advancement with LeFort osteotomies may in rare circumstances damage the greater palatine vessels and the blood supply to the maxilla. Palatal and tonsil surgery may also impair collateral blood flow to the maxilla andin the rare event this occursincrease the risk of avascular necrosis. Those likely to undergo maxillofacial surgery should have this issue discussed. Prior radiationtissue ablation (sclerotherapy or radiofrequency)and patients with extensive small vessel disease (diabetesheavy smokers) may increase the risk of wound breakdown. Surgeons should also have adequate resources to address oronasal fistula.