Repeated Superiorly Based Pharyngeal Flap Operation for Persistent Velopharyngeal Incompetence BERNARD HIRSHOWITZ, FR.C.S. DAHLIA BAR-DAVID, M.S. Haifa, Israel Introduction Although considerable improvement in speech is to be expected following a pharyngeal flap operation for velopharyngeal (v.p.) incompetence (v.p.i.), there are a number of patients whose speech remains poor following this procedure. Most of these patients have had cleft palate repair but have been left with an oversized v.p. lumen. V.P. lumen size has been correlated by Warren (8) with degree of speech competency. He has reported that, when the V.P. lumen size is greater than 20 sq. mm., hypernasality with gross nasal escape is usually present. The goal of pharyngeal flap surgery for some surgeons is to reduce v.p. lumen area to less than 20 sq. mm. during speech. However, if the pharyngeal flap is too small or if the surgical technique has somehow been faulty, the re- quired reduction in the v.p. lumen may not be achieved. What to do subse- quently has been problematic. It has now been found possible to repeat a supe- riorly based pharyngeal flap, and gratifying improvement in speech has been observed following superimposition of the newly-transposed tissue onto the existing flap. Three patients have been operated on by this technique, and in all instances marked reduction in hypernasality has been obtained. The work re- ported here is in general agreement with that of Cosman and Falk (2). Surgical Procedure General anaesthesia with endotracheal intubation and a Dingman or Dotts mouth gag are used during the procedure. Incisions are made for a secondary superiorly based pharyngeal flap of maximal width and adequate length with the base of this flap reaching the level of the base of the original pharyngeal flap. This new flap is bisected by a midline vertical incision, and two lateral flaps are thereby created (Figure 1). The lateral incisions are elongated in a cranial direction and reach a higher level than the midline incision. This makes the base of each flap somewhat oblique thereby adding to its width. The midline incision continues proximally into the base of the original pharyngeal flap and proceeds along the full length of The authors are affiliated with Rambam University Hospital, Abba Khoushy School of Medicine, Haifa, Israel. ' 45 46 Hirshowitz and Bar-David FIGURE 1. This drawing shows the outline of a secondary pharyngeal flap, which is bisected into two lateral flaps by a midline vertical incision. The hatched line indicates the continuation of the incision along the original flap and onto the upper surface of the posterior border of the soft palate. Here a sub-mucous pocket is made on either side by dissecting the mucous membrane off the muscle. its antero-inferior surface to the junction with the soft palate. From here the incision extends onto the upper surface of the posterior border of the soft palate, and" continues laterally on both sides to the anterior pillars of the fauces. A sub-mucous pocket is made in the soft palate on either side by dissecting the nasal mucous membrane off the muscle. The two lateral flaps are now elevated off the pre-vertebral fascia along their full length and are rotated upwards approxi- mately 90°. Their tips are fitted into the previously made sub-mucous pockets where they are secured by through and through silk sutures (Figure 2). The REPEATED PHARYNGEAL FLAP SURGERY 47 H. ta a de Th FIGURE 2. This drawing illustrates the raising and rotation upwards of the two lateral flaps, so that their tips come to fit into sub-mucous pockets. medial margin of each lateral flap impinges on the split antero-inferior surface of the primary pharyngeal flap, and union occurs along these edges. In view of the tethering of the soft palate to the posterior pharyngeal wall by the original pharyngeal flap, each lateral flap does not have to be too long for its tip to reach the soft palate. The resultant satisfactory relationship between the flap's length and its width provides the flap with an adequate blood supply in spite of scarring from previous surgery in this area. No effort is made to close the donor site by approximating the lateral wound margins, and healing has nonetheless been uneventful. Discussion Residual hypernasal speech following a pharyngeal flap operation for the correction of velopharyngeal incompetence (VPI) occurs in a not insignificant number of patients. In a series of 35 patients with V.P.I. who had pharyngeal flap surgery, Whitaker et al (9) reported that 17 per cent still had V.P.I. Owsley (4), in a series of 34 patients who had had high superiorly based pharyngeal flap surgery for V.P.I., reported that 14 per cent of the patients were either left with 48 __ Hirshowitz and Bar-David moderate nasality or showed no improvement in speech. In Skoog's results (6) on 49 patients who had had superior based flaps and palatal push-backs for V .P.I., 20 per cent were left with unacceptable speech. In response to this persistent failure rate following pharyngeal flaps many types of implants have been inserted into the posterior pharynx with the aim of bringing it forward in order to facilitate speech. However, Blocksma & Brailey (1), in a survey of 262 surgeons who performed surgery for V.P .I., found that 50 per cent disapproved of or were undecided about the retropharyngeal implant principle. Owsley, et al (5) suggest that poor speech may result from a restrictive pharyngeal flap producing traction in an inferior or straight posterior direction. They advocate division of the flap and reattachment of a new high anteriorly attached flap in order to improve speech. These authors confirm an interesting observation that the posterior pharyngeal wall looks unscarred despite its being a donor site for the previously transferred flap. This relative paucity of scarring makes it possible to raise a second pharyngeal flap which in turn can be superimposed upon an existing flap. Another interesting finding that we have observed when raising a second pharyngeal flap is the presence of a muscular layer similar to that found in a primary flap. This is probably to be expected, however, as reduction in the lateral dimension of the pharynx usually accompanies pharyngeal flap transfer. This implies a smaller cross sectional diameter allowing the lateral cut edges of the constrictor muscles to approximate each other in the midline (Figure 3). This muscular layer is of importance in that it adds bulk to the flap and, by bringing with it additional blood supply, helps to ensure the flap's viability. Scar FIGURE 3. This shows schematically the reduction in the crosssectional diameter of the pharynx following transfer of a pharyngeal flap and healing of the donor site with minimal scarring. The cut edges of the constrictor muscles, by approximating each other near the midline, ensure that the secondary flap has a good muscle layer. REPEATED PHARYNGEAL FLAP SURGERY: 49 It is our belief that a pharyngeal flap of maximal length and encompassing the full width of the posterior pharyngeal wall usually ends up being attenuated and much shorter than it was originally. This associated linear contraction of the flap causes the soft palate to be pulled posteriorly with resultant lengthening. By the same token, subsequent linear contraction of each secondary flap produces a further posterior pull on the soft palate. It may be postulated that the original flap causes tethering of the soft palate in the midline, whereas the secondary flap exerts posterior traction on the lateral aspects of the palate. A certain amount of proximal raising of the base of the primary flap can be achieved by undermining the base of each lateral flap. This is possible since the base of each lateral flap is contiguous with the base of the original flap. The low attachment of the original flap which Owsley, et al (5) regard as being dele- terious to good speech can be overcome to a limited extent by this procedure. The shape of the velopharyngeal orifice, after pharyngeal flap transfer, resembles that of a double arch with the original flap acting as the central pillar. Superimposing the two lateral flaps (which are attached as far out as the fauces) onto this double arch results in direct narrowing of both velo-pharyngeal orifices and, thus, in reduction of nasal escape. The combined factors described above lead to an overall diminution of V.P. lumen size. There appears to be further reduction in the cross sectional diameter of the pharynx following healing of the donor site. The impression created by the two post-operative photographs (Figures 4 and 5) is that of a diaphram with two lateral holes or slits. This appearance would probably approximate that aimed at by Hogan, et al. (3) who describe the lateral - port control principle. It is quite surprising with what small V.P. lumen orifices the patients have actually been left. Two of our patients began to snore after the second pharyngeal flap operation. (In one, the snoring was transient.) Another has become a mouth breather during sleep. However, the improvement in speech would appear to compensate amply for these disadvantages. When the soft palate is unduly short, scarred, and distorted, no matter how big a pharyngeal flap is made, it cannot always be expected to reduce the V.P. lumen size sufficiently to eliminate hypernasality. It is perhaps precisely in such situations that the repeated pharyngeal flap may have its main application. It is realized that the shortcoming of this paper is that our experience is based on only three cases.