1 INTRODUCTION

Snoring results from the vibration of the soft tissues in the oral cavity – the soft palate, uvula, tonsils, base of tongue, epiglottis and lateral pharyngeal walls. These vibrating soft tissues when subjected to negative pressure within the upper airway may lead to collapse of the upper airway. It is known that when inspiratory transpharyngeal pressure exceeds the pharyngeal dilating muscle action, apneas and hypopneas occur.¹ Collapse of the upper airway is usually multilevel, at the level of the velopharynx, the base of tongue, and the lateral pharyngeal walls. Many patients with obstructive sleep apnea (OSA) have bulky thick lateral pharyngeal walls that vibrate and contribute to the collapse of the upper airway in these patients. The level of collapse is assessed using the Mueller maneuver recorded with fiberoptic flexible nasopharyngoscopy. The Mueller maneuver is usually graded on a five-point scale, 0 to 4.² Terris et al. described the Mueller maneuver finding based on three levels: soft palatal collapse, lateral pharyngeal wall collapse and base of tongue collapse.³ Lateral pharyngeal muscle wall collapse has been demonstrated to be important in the pathogenesis of OSA in imaging studies.^4,5 It is well known that lateral pharyngeal wall collapse plays a significant role in the pathogenesis of OSA. Most authors concur that it is difficult to create, surgically, adequate lateral pharyngeal wall tension to prevent its collapse.

Lateral pharyngoplasty, first described by Cahali,¹ was aimed at addressing lateral pharyngeal wall collapse in patients with OSA. The procedure showed promising results; however, many patients had prolonged dysphagia postoperatively.

The ideal procedure would involve one that is easy to perform, with low morbidity, minimal complications and not requiring any special equipment.

Orticochea⁶ first described the construction of a dynamic muscle sphincter, by isolating the palatopharyngeus muscle and transposing it bilaterally, superiorly in the midline, for treatment of velopharyngeal incompetence in patients with cleft palates. Christel et al.⁷ modified Orticochea’s procedure, by isolating the palatopharyngeus muscle bilaterally, apposing it more superiorly and closing the lateral pharyngeal defects with Z-plasty sutures. Utilizing these procedures, the authors present an innovative technique in creating this tension in the lateral pharyngeal walls, preventing its collapse and reducing the number of apneic episodes. The expansion sphincter pharyngoplasty basically consists of a tonsillectomy, expansion pharyngoplasty, and rotation of the palato­pharyngeus muscle, a partial uvulectomy and closure of the anterior and posterior tonsillar pillars.

2 PATIENT SELECTION

The authors conducted a prospective randomized clinical trial in 45 adults, age above 18 years old, who have mainly type I Fujita (retropalatal obstruction) and lateral pharyngeal wall collapse. The inclusion criteria included patients with small tonsils (tonsil size 1 and 2), Body Mass Index (BMI) < 30, and Friedman clinical stage II and III who had failed or cannot tolerate nasal continuous positive airway pressure (CPAP) therapy. The clinical examination included height, weight, neck circumference, BMI, and assessment of the nasal cavity, posterior nasal space, oropharyngeal area, soft palatal redundancy, uvula size and thickness, tonsillar size and Friedman tongue position. Flexible nasoendoscopy was performed for all patients, and collapse during a Mueller’s maneuver was graded for the soft palate, lateral pharyngeal walls and base of tongue on a five-point scale.³ These patients were randomized into either the traditional uvulopalatopharyngoplasty (UPPP) procedure or the expansion sphincter pharyngoplasty (ESP). The mean follow-up time was 6.5 months. All patients had a postoperative polysomnogram at 6 months.