TRANSPALATAL ADVANCEMENT PHARYNGOPLASTY FOR OBSTRUCTIVE SLEEP APNEA B. TUCKER WOODSON, MD
It has been widely accepted dogma that palatopharynogoplasty failure occurs from obstruction at nonpalatal sites. Accumulating data suggests that obstruction is multilevel, and persistent palatal levels of obstruction occur after palatopharynogoplasty failure. A procedure which advances the soft palate rostrally to enlarge the retropalatal airway is described.
Uvulopalatopharyngoplasty (UPPP) and laser assisted palatoplasty performed for obstructive sleep apnea (OSA), remains controversial. Success is inconsistent. Treatment reduces snoring in most patients. Mild apnea improves in many but in severe apnea, short term success (defined as a respiratory disturbance index [RDI] of less than 20 events/h, or an apnea index [AI] of less than 10 events/h) is infrequently successful as an isolated procedure. ~,2Failure is likely multifactorial but studies suggest that for a number of patients, the upper pharynx or retropalatal segment continues to obstruct. 3,4 To address persistent retropalatal airway obstruction, transpalatal advancement pharyngoplasty was developed. 5 Historically, multiple different techniques for UPPP are described. They may significantly differ. Fujita et al, modified Ikamatsu's palatopharyngoplasty, which he had described for snoring and proposed UPPP for OSA. 6,7Fujita's technique conceptually excised the tonsils, redundant pharyngeal tissue, and uvula. Palatal muscles were spared. The objective measures of respiratory outcome showed a 50% reduction in apnea indices in 50% of patients. The attempts to improve outcome were tested by removing more tissue of the palate and velopharynx. This included attempts to open the airway by complete excision of the palatopharyngeus muscle. 8 Aggressive resection did not improve success rates but did result in higher rates of complications related to velopharyngeal dysfunction. 9 Another modification, laser assisted uvulopalatoplasty (LAUP) was introduced by Kamami for snoring 1° and subsequently for OSA. The definition of LAUP is unclear with many techniques also described. LAUP success rates for OSA syndrome are debatable but 30% to 40% success rates in mild or moderate disease have been reported. No palatopharyngoplasty technique has achieved wide acceptance or effectiveness. The goal of surgery for OSA is to maintain unobstructed ventilation during sleep without speech or swallowing morbidity. Pharyngeal surgery likely is effective in apnea by increasing airway size and decreasing collapsibility. 11,12 From the Department of Otolaryngology and Communication Sciences, The Medical College of Wisconsin, Milwaukee, Wl. Address reprint requests to B. Tucker Woodson, MD, Department of Otolaryngology and Communication Sciences, The Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, W153226. Copyright © 2000 by W.B. Saunders Company 1043-1810/00/1101-0009510.00/0 36
Altering airway shape and stabilizing length also may be important changes. 13,14Effectiveness for snoring must not be confused with effectiveness for OSA. Snoring is primarily a palatal disorder. UPPP likely alters snoring by shortening and stiffening the palate that left untreated acts like a flutter valve. 15 OSA may result from multiple collapsing airway segments, which need to be enlarged to prevent airflow obstruction. It has been speculated that OSA patients and particularly UPPP failures have as a major contributor lower pharyngeal obstruction. Most untreated apneics, however, have retropalatal obstruction (50% to 80%) with the retropalatal airway being the primary site of sleeping airway obstruction. 16-18Because the palate and velopharynx are so critical, it is not surprising that obstruction and collapse often continue at the palate after UPPP failure. 3,4,19 Could further enlargement of the retropalatal space improve some surgical outcomes? There are several potential strategies to increase airway size of palatal surgery. Increases in airway volume and decreases in compliance may result from: (1) removal of redundant and obstructive tissues and tonsils, (2) approximation of the posterior to anterior pillars after excising lateral wall tissues, (3) shortening of the soft palate, (4) stiffening the lateral pharyngeal walls, and (5) advancing skeletal framework. Increasing oropharyngeal volume due to resection of soft tissues risks velopharyngeal damage because UPPP is solely a soft tissue procedure. UPPP effectiveness is constrained by the underlying anatomy and risks of velopharyngeal complications and often is not determined by the surgeon. An alternative hypothesis is that the retropalatal airway may be enlarged by advancing the soft tissues anteriorly. This is performed by transpalatal advancement pharyngoplasty. There is only scant data on clinical selection of patients for transpalatal advancement pharyngoplasty. Patients selected for transpalatal advancement pharyngoplasty may include patients with previous UPPP failure who refuse maxillofacial advancement. Patients with narrowing of the retropalatal space above the margin of anticipated or prior UPPP excision also may be candidates.
INCLUSION/EXCLUSION Patients who may be excluded for palatal advancement would be patients with velopharyngeal insufficiency, submucous cleft palate, or impaired pharyngeal swallowing.
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 11, NO 1 (MAR), 2000: PP 36-40
tered perioperative antibiotics and dexamethasone. One percent xylocaine with 1:100,000 epinephrine is infiltrated into the greater palatine foramen, the hard soft palate junction, and the planned incision sites before the procedure for hemostasis. A vasoconstrictor (oxymetazoline spray) is applied to the nose to reduce mucosal bleeding. In the first step, removal of hypertrophic tonsils, redundant mucosal tissues, and obstructed uvula may be performed (Fig 1). This may not be required in all patients. Next, a palatal incision begins at the central hard palate posterior to the alveolus and continued posteriorly, in a curvilinear fashion immediately medial to the greater palatine foramen. The tip or cephalic end of the flap needs to lie at least 1 cm proximal to the margin of the bone removal. The incision is then flared laterally over the palpable process of the hamulus to the buccal mucosa. A mucoperiosteal flap is elevated exposing the hard palate and the proximal soft palate (Fig 2). In the midline, the palatal mucosa is often thin and care must be taken in elevation not to tear tissue. Laterally and posteriorly, the submucosa of the flap is thicker fibroadipose tissue and is bluntly dissected with the sharp edge of the mastaird curette. There usually is minimal bleeding if an adequate waiting time for vasoconstrictor effect has been used.
FIGURE 1. Transpalatal advancement pharyngoplasty may be performed simultaneously with conservative uvulopalatopharyngoplasty or uvulopalatal flap. Only soft tissue redundancy should be removed and dissection should avoid the lateral pharyngeal walls. The palatal incision begins posterior to the alveolus approximately 2 cm anterior to the posterior border of the hard palate. The incision using cutting electrocautery is carried medial to the greater palatine foramen. The incision is carried down to the bone only in the midline and is superficial only through the mucosa laterally to avoid injuring the palatine vessels.
Patients who have had prior palatal surgery need either an endoscopic or barium swallow study. Patients with dentures must be cautioned not to wear dentures for 3 to 4 weeks postoperatively. They also need to be cautioned that the dentures may need to be refit because of structural changes. Patients with macroglossia and an enlarged tongue, which obstructs the oral airway, may be poor candidates because pulling of the palate forward may further obstruct this route of breathing. Lastly, patients who are serious candidates for bimaxillary advancement should defer palatal advancement and use traditional techniques because the effects of palatal advancement on maxillary blood flow are unknown. This blood flow may be important in some individuals after maxillofacial surgery.
SURGICAL TECHNIQUE The procedure is performed under general anesthesia. Patients are placed supine in the Rose position. Exposure is obtained with a Dingman mouth gag. Patients are adminisB. TUCKER WOODSON
FIGURE 2. The palatal flap is elevated beginning In the midline where the mucosa is thin. Laterally, the fibro-adipose tissue can be bluntly incised to elevate the flap. The palatine vessels are therefore preserved. Elevation continues posteriorly along the hard palate and is continued in a plane superficial to the tensor aponeurosis. The mucosal flap is elevated to expose 5 to 8 mm of tensor aponeurosis. This provides adequate tissue to grasp subsequent sutures but avoids excessive devascularization of the flap.
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When the tensor aponeurosis is reached, the plane of elevation is superficial to the tendon and muscle. Only enough tensor tendon is exposed to provide a grasp for subsequent sutures, usually 5 to 8 mm. Electrocautery is used so that the soft palate is separated from the hard palate and the nasopharynx is exposed (Fig 3). A posterior portion of the hard palate is removed. A Kerrison rongeur or drill removes a 1-cm margin of the hard palate. This includes the central palate exposing the posterior nasal septum (Fig 4). Bleeding may be controlled with suction electrocautery. Palatal burr holes are placed at a 45 ° angle to the palate, extending from the oral surface of the palate into the nasal cavity (Fig 5). Particular care is needed if the palatal processes of the maxillary bone are thin. Several millimeters of bone need to remain to support the anchoring sutures. A tapered free needle then passes a doubled suture through the drill holes into the nasopharynx. The suture is grasped in the nasopharynx and is withdrawn from the mouth. Care must be taken not to torque on the needles to prevent fracture of the palatal bone. Sutures are then secured medially and laterally in the tensor aponeurosis. A figure-of-eight suture is easier and less traumatic to place compared with a simple suture. The soft palate is mobilized using steady anterior traction with a finger or blunt instrument behind the palate. While an assistant retracts the palate anteriorly, the sutures are tied. Redundant mucosa may or may not need to be trimmed and a tension free closure is performed with fine absorbable v
FIGURE 4. An 8 to 10 mm portion of the hard palate is removed using a Kerrison rongeur or drill. Care must be taken to avoid damaging the inferior turbinates or lateral nasopharyngeal walls.
sutures. A regular diet may begin on the first day. The use of an upper denture is avoided until healing is completed. Transpalatal advancement pharyngoplasty may significantly reduce both RDI and AI (Table 1). In the series, transpalatal advancement produced a 67% response rate (defined as an RDI of less than 20 events/h). RDI in the responder group decreased from 52.8 + 12.3 events/h (Fig 4). AI decreased from 39.0 + 2.3 events/h. The initial report was confounded by multiple level of airway obstruction and multiple procedures. No patient developed changes in speech or velopharyngeal function, however, transient symptoms of mild nasopharyngeal reflux similar to experience with UPPP may occur. Mild intermittent oropharyngeal dysphagia requiring multiple swallows to clear may transiently occur. All patients have had spontaneous resolution by 6 weeks. Partial palatal flap necrosis, oronasal fistula, and serous otitis media are infrequent but potential risks.
AIRWAY STUDIES
FIGURE 3. Electrocautery is used to separate the soft and hard palates and expose the nasopharynx. Occasional bleeding at the point of the posterior septum can be controlled with Bovie electrocautery.
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Although the outcomes improve in patients with severe OSA, the small group limits conclusions and large numbers are needed to confirm early enthusiasm. Comparing palatal surgeries for OSA syndrome using clinical outcomes is confounded by multiple variables including obstruction at sites not directly affected by surgery, disease severity, and other risk factors. Retrospective review of
TRANSPALATAL ADVANCEMENT PHARYNGOPLASTY FOR OSA
Resected hard palate FIGURE 5. Palatal burr holes are placed at a 45 ° angle to the palate. Several millimeters of bone are needed to support the anchoring sutures. A tapered free needle is then passed into the nasopharynx with attached suture. Medial and lateral sutures are placed bilaterally into the tensor tendon of the soft palate. The palate needs to be mobilized and a finger applying anterior traction. The soft palate is held in place while sutures are tied.
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small n o n r a n d o m g r o u p s w i t h inconsistent follow u p d o n o t clarify efficacy, a° P r o c e d u r e s m a y be c o m p a r e d a n d e v a l u a t e d , h o w e v e r , b a s e d o n their effect o n m o d i f y i n g the u p p e r a i r w a y size a n d collapsibility. In 7 subjects w i t h severe OSA, U P P P a n d a d v a n c e m e n t p h a r y n g o p l a s t y w e r e c o m p a r e d . 21 After each p r o c e d u r e p r e s s u r e area m e a s u r e m e n t s of the retropalatal a i r w a y s e g m e n t w e r e obtained. Variable positive a n d n e g a t i v e a i r w a y p r e s s u r e w a s a p p l i e d to the isolated u p p e r a i r w a y ( - 8 . 0 to +18.0 c m / H a O ) . The area w a s e n d o s c o p i c a l l y m e a s u r e d a n d recorded. P r e s s u r e area c u r v e s w e r e d e f i n e d as a p l o t of the v a l u e s of retropalatal area a n d a p p l i e d m a s k pressure. C l o s i n g p r e s s u r e (Pclose) is the a p p l i e d p r e s s u r e w h e n retropalatal a i r w a y area w a s zero. M a x i m a l retropalatal area increased 220% in patients after transpalatal a d v a n c e m e n t p h a r y n g o p l a s t y c o m p a r e d w i t h UPPP. M a x i m u m area increased f r o m 61.5 + 4.6 m m 2 to 135.6 + 26.2 m m 2 (P < .001). C l o s i n g p r e s s u r e d e c r e a s e d f r o m a m e a n of 5.0 c m HaO p o s t U P P P to a m e a n - 9 . 2 c m H 2 0 after t r a n s p a l a t a l a d v a n c e m e n t (P < .001).
CONCLUSION Transpalatal a d v a n c e m e n t p h a r y n g o p l a s t y offers a p o t e n tial alternative to a g g r e s s i v e resection of soft tissue u s i n g traditional U P P P in an a t t e m p t to enlarge the u p p e r o r o p h a r y n g e a l a i r w a y a n d i m p r o v e r e s p i r a t o r y results. Transpalatal a d v a n c e m e n t is o n l y a p a r t of the surgical p l a n for the t r e a t m e n t of OSA. T r e a t m e n t m u s t i n c l u d e a s s e s s m e n t of the entire u p p e r airway. All s e g m e n t s of the
TABLE 1. Respiratory Results of Transpalatal Advancement Pharyngoplasty
RDI AI 02 SAT
Total n= 6
Responders n = 4 (67%)
69.3 +_ 32.1" 26.6 _+ 25.3 50.3 _+ 39.8* 11.7 _+ 22.9 75.0 _+ 7.1 73.8 _+ 9.5
52.8 12.3 39.0 2.3 79.3 77
_+ 12.2" _+ 2.8 -+ 13.2" _+ 2.7 -+ 3.1 _+ 9.6
Non-Responders n = 2 (33%) 102.6 55.9 74.0 30.6 68.5 69
_+ -+ _+ _+ _+ _+
* P < .01. Adapted with permission from Woodson BT, Toohill RJ: Transpalatal advancement pharyngoplasty for obstructive sleep apnea. Laryngoscope 103:269-276, 1993. 5
B. TUCKER WOODSON
....
Resected ',.,' uvula
a i r w a y b o t h nasal, palatal, t o n g u e base, a n d h y p o p h a r y n geal n e e d to be m a x i m i z e d if s u r g e r y is to be effective.
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TRANSPALATALADVANCEMENT PHARYNGOPLASTY FOR OSA