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.

3 SURGICAL TECHNIQUE

The procedure is done under general anesthesia, with the patient in the supine position. The authors perform the procedure with orotracheal intubation, and a Boyle–Davis mouth gag within the oral cavity keeping the mouth open, and isolating the endotracheal tube forwards. A bilateral tonsillectomy is performed (Fig. 37.1). The palatopharyngeus muscle is identified; its inferior end is transected horizontally (Fig. 37.2). The muscle is isolated and left with its posterior surface partially attached to the posterior horizontal superior pharyngeal constrictor muscles (Fig. 37.3). It is rotated superolaterally with a figure 8 suture, through the muscle bulk itself, with a Vicryl 3/0 round body needle. A superolateral incision is made on the anterior pillar arch bilaterally, identifying the arching fibers of the palatoglossus muscles (Fig. 37.4). The palatopharyngeus muscle is then attached to the arching fibers of the soft palate anteriorly and a partial uvulectomy is then performed (Fig. 37.5). The anterior and posterior tonsillar pillars are then apposed with Vicryl sutures (Fig. 37.6). The same steps are repeated on the opposite side. This new technique of expansion sphincter pharyngoplasty was modified from the Orticochea procedure and lateral pharyngoplasty. The principle of this technique is to isolate the palatopharyngeus muscle (the main part of the lateral pharyngeal wall bulk) and rotate this muscle supero-anterolaterally, in order to create the lateral wall tension and remove the bulk of the lateral pharyngeal walls. The key is to not completely isolate the muscle into a tube and rotate it, but rather to keep part of its fibrous attachment to the superior pharyngeal constrictor muscle, so as to create the necessary tension and pull supero-anterolaterally. A complete or partial uvulectomy is performed together with this procedure.

Fig. 37.1

Fig. 37.2

Fig. 37.3

Fig. 37.4

Fig. 37.5

Fig. 37.6

There are no significant complications; primary or secondary hemorrhages are not increased and are rare; fistulations of the soft palate and oral infections hardly occur.

4 POSTOPERATIVE MANAGEMENT ANDCOMPLICATIONS

All patients were monitored in the postanesthesia care unit for 4 hours before being transferred to the high-dependency ward for overnight monitoring. Monitoring included continuous pulse oximetry, blood pressure and pulse rate. They were given adequate analgesia, in the form of anesthetic gargles (Difflam) and lozenges (Difflam), non-steroidal anti-inflammatory agents (naproxen sodium), and cyclo-oxygenase-2 inhibitors. Most patients were discharged on the first postoperative day. All patients were advised to have adequate oral fluid hydration and a soft blended diet in the first postoperative week. There were no complications from this procedure; there was no primary or secondary hemorrhage; and there were neither fistulae of the soft palate nor any oral infections.

5 SUCCESS RATE OF PROCEDURE

There were 45 patients enrolled (22 UPPP, 23 ESP). Forty-one patients were men and four were women. The mean age was 42.1 years (range of 24 to 47 years), the mean BMI was 28.7 (range of 21.7 to 29.8). The mean preoperative Apnea/Hypopnea Index (AHI) for the entire group improved from 42.3±17.1 to 19.2±12.0 postoperative with a mean follow-up of 6.5 months. The AHI improved from 44.2±10.2 to 12.0±6.6 (P<0.005) following ESP and from 38.1±6.46 to 19.6±7.9 in the UPPP group (P<0.005). Mean change was 27.5±8.4 in ESP and 18.5±7.6 in the UPPP group. Lowest oxygen saturation improved similarly from 78.4±8.52 to 85.2±5.1 in the ESP group (P=0.003) and from 75.1±5.9 to 86.6±2.2 in the UPPP group (P<0.005). Selecting an arbitrary threshold of a 50% reduction in AHI and AHI < 20, success was 82.6% in ESP compared to 68.1% in UPPP (P<0.05). Of great interest, when selecting an arbitrary threshold of a 50% reduction in AHI and AHI < 15, the ESP success rate was at 78.2%, compared to that of the UPPP group at only 45.5%. Postoperative endoscopic findings demonstrated significant reduction of lateral pharyngeal wall collapse in the ESP group.

The lateral pharyngoplasty technique, described by Cahali, showed that ten patients with moderate to severe OSA, and who had mainly lateral pharyngeal wall collapse noted on clinical endoscopic examination, had promising results.¹ All ten patients had improvements in their AHI, with a mean of 45.8, reducing to 15.2 (P=0.009) postoperatively, with a mean follow-up of 8 months. There was also improvement in Apnea Index (AI), with a reduction from a mean of 22.4 to 4.8 (P=0.005). There were, however, significant swallowing problems in all ten patients who underwent this procedure. All patients had dysphagia; this ranged from 8 days to 70 days postoperatively (mean 20.4 days). One patient had persistent velopharyngeal insufficiency for up to 6 weeks. Another patient had permanent loss of taste for chocolate for 6 months. Cahali et al.⁹ compared lateral pharyngoplasty with the traditional uvulopalatopharyngoplasty in 27 patients with OSA. All 15 patients who underwent lateral pharyngoplasty achieved significant reduction in excessive daytime sleepiness, AHI and AI. There were also improvements in the REM sleep percentage and morning headaches in patients who had lateral pharyngoplasty, compared to those who underwent the traditional uvulopalatopharyngoplasty. They concluded that patients who underwent the lateral pharyngoplasty technique have better clinical and polysomnographic results.

This new technique of expansion sphincter pharyngoplasty may offer benefit over traditional methods of UPPP in a selected group of OSA patients with small tonsils, Friedman Stage II and III and lateral pharyngeal wall collapse noted on endoscopic examination. The procedure has promising results, it is anatomically sound, and has minimal complications.