|Year : 2014 | Volume
| Issue : 1 | Page : 11-16
Buccinator myomucosal flap in cleft palate repair: Revisited
Consultant Plastic Surgeon, Rajkot, Gujarat, India
|Date of Web Publication||5-Feb-2014|
Heal-Well Hospital, Gujarat Housing Board - M/53, Opp. Swaminarayan Temple, Kalawad Road, Rajkot-360 001, Gujarat
Source of Support: None, Conflict of Interest: None
Objective: To present various ways of transfer and result of buccinator myomucosal flap (BMMF) in primary and secondary repair of palatal cleft and palate fistula. Design: This study has been designed on the basis of a clinical experience and literature search. Route of single or two BMMF(s) transfer was either lateral or posterior to the greater palatine neurovascular bundle. The flap has been used to repair defect in nasal layer, oral layer, or in combined nasal as well as oral layer of the palate. Materials and Methods: More than 160 palatoplasties have undergone palate repair with the use of BMMFs between 1999 and 2011. The analysis includes 98 palate repair. Unilateral flap was used most commonly in primary repair of nasal side of wide unilateral cleft palate (CP); whereas, two flaps were used mostly in primary repair of wide bilateral CP and in secondary palate repair for large fistula. Results: The fistula rate; in primary palatoplasty patients was 4.8% and in secondary palatoplasty patients, it was 8.3%. Good speech has been achieved in primary palatoplasty patients. After secondary palatoplasty also patients had good speech following therapy. Conclusion: The presented technique has been effective in anatomical and functional repair of wide palatal defects primary as well as secondary. The literature has been reviewed along with.
Keywords: Buccinator myomucosal flap, buccal flap, cleft palate, large palatal fistula/defect, palate fistula, Soft palate lengthening, velopharyngeal incompetence, wide palatal cleft, wide cleft palate
|How to cite this article:|
Bhayani B. Buccinator myomucosal flap in cleft palate repair: Revisited. J Cleft Lip Palate Craniofac Anomal 2014;1:11-6
| Introduction|| |
High fistula rate and inferior speech results are common after primary repair of substantially wide cleft palates (CPs). In wide CP, the defect created in nasal layer after 'back-cut' to lengthen it, is very large. Without the addition of additional vascular tissue; the chances of fistula, dehiscence, scarring, anterior reattachment of the reconstructed levator muscular sling, and loss of the lengthening of soft palate are high.  Serious scarring in hard palate, after secondary healing adversely affects the maxillary growth and dentition. The patients with wide CP end up as "cleft palate cripple" after two or three reparative attempts as far as the dentition, maxillary growth, and speech are concerned.
To cover the defect in nasal layer after the 'back-cut'; split thickness skin graft,  buccal mucosa graft, , Z-plasty, , nasal mucosal flap, , midline posterior pharyngeal wall flap, , lateral pharyngeal flap,  mucoperiosteal island flap,  buccal mucosal, ,,,,, and vomer flap ,, have been used. But in substantially large defect, with exception of buccinator myomucosal flap (BMMF), Z-plasty, vomer flap, nasal mucosal flap are inadequate; split thickness skin graft, buccal mucosal graft are unpredictable; and pharyngeal flaps and mucoperiosteal islanded flap are potentially hazardous. Except BMMF, and facial artery musculomucosal (FAMM) flap, none facilitate combined oral and nasal layer repair.
We are using this flap in repair of primary and secondary palatoplasty for large palatal defect since 1999. A set of line diagrams and photographs have been presented to illustrate the flap anatomy, its transfer and variety of insetting depending upon the defect. Observations made in 98 palate surgery patients are presented.
| Materials and Methods|| |
The data of 98 BMMF performed in 50 primary palatoplasty and 48 secondary palatoplasty were analyzed retrospectively. Patients' age, type of cleft, fistula rate, flap necrosis, and donor site morbidity were recorded. In all patients the speech evaluation consisting of nasal emission, hypernasality, hyponasality, and phonation and articulation was done by a senior speech therapist. The quality of speech was ranked as normal, mild, moderate, or severely compromised. The children of less than 3 years of age at surgery were assessed postoperatively at completion of 3 years or little late. The children of more than 3 years of age at surgery were assessed for speech at preoperative and then at 6 months postoperatively, and finally at the completion of speech therapy.
Surgical anatomy of buccal myomucosal flap
Buccal artery is a branch from second part of internal maxillary artery, accompanying buccal vein and buccal nerve a branch of mandibular nerve enter the flap base from the lateral side at posteroinferior part of the buccinator muscle at buccal sulcus lateral to the pterygomandibular rhaphe. The branches of the buccal artery, vein and the nerve fan out anteriorly from the narrow base of the flap [Figure 1] and [Figure 2]. The buccal vessels generously supply the buccinator muscle and the underlying cheek mucosa as well as the mucosa overlying the superior alveolar ridge and lateral part of soft palate. 
|Figure 1: Neurovascular supply of buccal myomucosal flap. 1 = Second part of maxillary artery, 2 = buccal artery, 3 = buccal nerve, 4 = buccinator muscle, 5 = facial artery|
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|Figure 2: 1 = Buccinator myomucosal flap (BMMF), 2 = buccal artery, 3 =facial artery, 4 = parotid duct opening, 5 = greater palatine neurovascular bundle, 6 = proposed extension of BMMF|
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The terminal branches of the buccal artery at the anterior part of the cheek mucosa anastomose with the ramified branches of the facial artery as it courses upward and anteriorly towards the nose.  The buccal myomucosal flap has a rich venous drainage system composed of internal maxillary vein, anteriorly tributaries of facial vein, and posteriorly pterygoid plexus.  Motor supply of buccinator muscle is through the lower buccal branches of facial nerve, entering the muscle from the lateral aspect.
This vascular supply gives this flap the virtue of an axial pattern myomucosal flap. As the buccal nerve enters the cheek mucosa at the base of the flap in proximity of the buccal artery, this flap naturally becomes a sensate flap.
A posteriorly-based pedicle flap is raised from cheek mucosa. The flap is pear-shaped and narrow at the base. It broadens anteriorly and tapers at distal end. In 1-1.5-year-old child, the flap size is 1.5-2 cm in width × 4-5 cm in length. The size is bigger in grown up children and adults. The maximum size can be 4 cm × 7 cm.
The flap can be islanded to facilitate rotation. Its base width, a little less than the length of pterygomandibular raphe, is kept, to avoid flap congestion and 'tip necrosis'. It allows easy and safe rotation and turn over. This width of base does not obstruct molar occlusion and allows a tension free closure of the donor defect without the need of undermining.
The upper border of the flap is marked at least 3 mm below the opening of parotid duct opposite the crown of the second molar of the maxilla. The distal end of the flap falls short of oral commissure by 0.5-1.0 cm to avoid distortion. The flap reaches anteriorly up to the anterior alveolar ridge; medially across the palate to the opposite greater palatine neurovascular bundle; posteriorly up to the base of the uvula [Figure 3]. This flap tolerates moderate stretching, pressure, and 180 degree rotation and twisting due to its inherent suppleness and elasticity.
|Figure 3: Dissected BMMF and its reach: BMMF (*) and Lt. sided mucoperiosteal flap (o)|
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Primary palate repair
Complete palate repair by Veau-Wardill-Kilner palatoplasty was carried out. Greater palatine neurovascular bundle is freed generously. The innervation of the palatal muscles are preserved as is essential for good muscular action postoperatively. 
A transverse back-cut is made on each side of nasal mucosa 0.5 cm behind the edge of hard palate for the retrodisplacement of the soft palate. The levator muscular sling is reconstructed in midline with 4/0 vicryl mattress sutures. The nasal side of the alveolar and hard palatal cleft is closed using existing mucoperiosteal flaps from vomer and edges of the alveolar cleft. Thereafter, BMMF is planned for remaining defect.
Secondary palate repair
For the fistula in hard palate, the nasal layer closure is done using hinged flaps from the surrounding marginal mucoperiosteum. If that is not sufficient, bilateral BMMF for oral as well as nasal layer closure is planned. Raising the mucoperiosteal flaps from the rest of the hard palate and freeing of the greater palatine neurovascular bundle is carried out. If the soft palate is short and scarred with velopharyngeal incompetence (VPI) a 'back-cut' is given in the nasal layer to release the levators and palatopharyngeus from the hard palate edge and lengthen the soft palate. At this point the placement of the hard palatal mucoperiosteal flaps with BMMF and the route of the flap transfer is decided. As per the need, unilateral or bilateral flaps are harvested.
After the application of traction sutures at lip margin and applying moderate counter pressure on cheek from outside, the flap is marked and incised in composite thickness comprising of mucosa and buccinator muscle, sparing the buccopharyngeal fascia. Preservation of the buccopharyngeal fascia prevents herniation of the buccal fat pad and inadvertent injury to the branches of the facial nerve. The flap is elevated from the anterior end to the base. The dissection of the flap is easy through a loose areolar plane between the buccinator muscle and the buccopharyngeal fascia. The flap donor defect is closed primarily. The parotid duct opening is carefully preserved.
Flap transfer and inset
The dissected flap is transferred to the palatal defect either from posterior or from lateral side of the greater palatine neurovascular bundle. For the nasal layer defect, the flap is transferred through a tunnel, dissected out in to the soft palate, posterior to the 'bundle'. A generous tunnel is created by blunt dissection through the lateral releasing incision about 0.5 cm medial to pterygomandibular raphe. To transfer the flap from lateral side of the neurovascular bundle, either mucoperiosteal flap from the hard palatal shelf is elevated or the mucoperiosteum is dissected away from alveolar ridge. Thus, the BMMF has been used for palatal reconstruction either transversely or obliquely anteriorly. This can be used for reconstruction of nasal lining [Figure 4] and [Figure 5], oral surface defect [Figure 6], or both surfaces simultaneously [Figure 7] and [Figure 8] in variety of situations in primary and secondary unilateral and bilateral CP surgeries.
|Figure 4: (a) Central palatal fi stula with short and scarred soft palate. (b) Soft palate lengthened by 'push back' cuts. Right cheek BMMF (*) brought into nasal layer for the lining of the fistula as well as push back cuts defect. (c) Postop photo; fistula is closed and soft palate lengthened|
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|Figure 5: (a) Wide isolated cleft palate with small vomer. (b) A line diagram depicting restoration of the nasal layer by left BMMF (*) and right BMMF (o), arranged in "mirrored L" style|
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|Figure 6: (a) Hard palate palate long fistula. (b) Nasal side of the fistula is closed using marginal hinge flaps (?+). (c) The oral side of the fistula and the rest of the palate is restored by left BMMF (*), right BMMF (o), and the mucoperiosteal flap (^). (d) Postop photos (^)|
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|Figure 7: (a) A large oronasal fi stula following primary palatal repair. (b) The nasal layer of the fistula is reconstructed using right BMMF (o), passed through the 'tunnel'. The oral layer of the fistula is restored by left BMMF (*). This flap's pedicle is passing over the deepithelized track on soft palate|
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|Figure 8: (a) Very large oronasal fi stula. Left BMMF (*) is brought into the nasal side, passing over the deepithelized track on the soft palate. (b) A mucoperiosteal flap (o) covers the oral surface of posterior part of the hard palate oral side. (c) Right BMMF (^) covers the anterior part of the palate. (d) Photograph at the completion of surgery|
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- Single BMMF has been placed transversely to resurface the nasal layer defect. It can be used in a wide unilateral cleft lip and palate (UCLP); for large palate fistula [Figure 4]. It may have 'L' inset in wide bilateral cleft lip and palate (BCLP) [Figure 5] and in a wide CP.
- Double BMMF flap may be used for nasal layer defect resurfacing with 'T'-shape inset in UCLP and BCLP. There may be inset in 'mirrored L-shape' in isolated CP [Figure 5] and BCLP.
- Resurfacing of oral defect: Single flap can be used to resurface lateral defect in the hard palate [Figure 6] and bilateral BMMF can be used to cover the lateral defect on both the sides.
- Use of flaps for oral and nasal defects: Combined bilateral flaps can be used to cover oral and nasal defects in BCLP and large palate fistula [Figure 7] and [Figure 8].
- Two flaps have been used to cover a large anterior palate fistula by transferring them along the lateral raw area in the hard palate.
- Two flaps could be transferred through different routes to close the palate fistula [Figure 8] and in case of complete dehiscence of palatoplasty in BCLP.
This flap has been used in 50 primary and 48 secondary palatoplasty. Amongst primary; 26 (52%) are UCLP, 10 (20%) BCLP and 14 (28%) are isolated CPs. Amongst secondary palatoplasty; 21 (43.9%) had BCLP and 18 (37.5%) had isolated CP [Table 1].
Single BMMF was used for augmentation of nasal layer in primary UCLP repair. Double flaps were used in majority of BCLP and secondary palatoplasty [Table 1].
| Results|| |
This is a retrospective analysis of the patients undergoing palatoplasty, detail documentation was available for 98 patients requiring BMMF. Fifty one percent patients had primary palate surgery, while 49% had secondary palate surgery [Table 1]. There was a wide variation in age; from 1 to 25 years; 59% of primary palatoplasties were done between 1 and 1.5 years of age, while 9% were operated at reasonably later age. Only 12.5% of secondary palatoplasties were done in children of 2-3 years, while 31.3% were operated between 3 and 5 years of age. Fifty percent were operated later than 10 years of age.
The result of palate repair is gauged by occurrence of palate fistula. In this series of patients where BMMF has been used the palate fistula after primary palate repair was two out of 50 patients (4.0%). In both the cases, small perialveolar fistulae occurred which were closed with local flap later. The overall occurrence of fistulae after secondary palate repair was 8.3% (four out of 48 cases). All fistulae were perialveolar, three cases of BCLP and one case of UCLP. All the CP cases were fistula free.
One of the bilateral flaps had significant necrosis. This was placed on the oral surface. However, the flap on the nasal surface survived fully. Flap pedicle was divided in eight (8.2%) required flap division as the pedicle of the flap was covering the occlusal surface of third molar. None of the patients had significant donor area problem. None had any compromise in mouth opening.
Ninety percent of primary palatoplasty patients had normal speech, without speech therapy. Only five patients (10%) required postoperative speech therapy. In more than 3 years age group, speech quality was affected with increasing age, requiring prolonged speech therapy for the improvement. 79.2% of secondary palatoplasty patients had poor speech at preoperative assessment. All of them required postoperative prolonged speech therapy with substantial improvement in majority of them [Table 2].
| Discussion|| |
In clinically wide CP, a generous back-cut is required in nasal layer for the retrodisplacement of the soft palate to achieve adequate length. Additional tissue is required for primary healing of the palate and permanent lengthening of the soft palate with good mobility.
Baxter et al., (1949) used split thickness skin graft  and Webster and Spina et al., used buccal mucosa graft to cover nasal layer defects , created after 'back-cut'. But successful take of the graft without scarring was doubtful.  The Z-plasty of nasal mucosa , was not effective, due to the deficiency of nasal mucosa in the longitudinal as well as transverse axis.  For the same reason the use of the Furlow double opposing Z-plasty  to lengthen the nasal layer in very wide CP may not be effective. All these techniques, including the sliding of nasal floor mucoperisteum , are not effective because of anterior readhesion of levator muscular sling and loss of achieved length of soft palate.
Millard island flap  leaves large raw area in the hard palate, and decreases the mobility of the soft palate. It has been largely abandoned because of the impairment of the maxillary growth.  Posterior pharyngeal wall flap and lateral pharyngeal wall flap have potential risk of air way obstruction, hemorrhage, and disturbance in pharyngeal anatomy. , These flaps cannot reach into anterior palate and combined oral and nasal layer repair is not possible with them. Tongue flap is potentially risky as the pharyngeal flaps are. It can be used to cover the only the oral side of the defect.
The FAMM flap is another good option. Its maximum width can be 1.5-2.0 cm,  however we have raised much larger BMMFs. Sometime primary donor area closure is not possible in FAMM flap and may require split thickness skin graft. Anatomical variations of facial artery are reported. Postoperatively 'bite blocks' are necessary and all flaps require flap pedicle division. When BMMF is used to cover 'back-cut defect', the length of the soft palate was maintained; the flaps were appreciably matching with the nasal floor mucosa. 
In the present series of palatoplasty with BMMF, overall fistula rate after primary palatoplasty was 4.0% and in secondary cases it was 8.3% in perialveolar region. No fistula was found after wide isolated CP repair. There are many factors responsible for the occurrence of fistula. Increasing severity of cleft, possibly have more degree of muscular hypoplasia, smaller palatal shelves, and smaller vomer with less satisfactory results.  Some time in wide isolated CP and wide BCLP, vomer is not well-developed and there is very little tissue to provide a flap for nasal layer repair. 
It is possible to completely close even the widest CP with BMMF without the need for further procedure. It is safe and easy to perform in primary as well as secondary palatoplasty.  The speech result of palatoplasty using BMMF has been quite satisfactory in present series [Table 2]. After the secondary palatoplasty improvement in speech is likely to be due to the successful closure of fistula and achievement of adequate lengthening of soft palate with good mobility.
BMMF is a vascular and dependable flap. Vascular supply of the flap is consistent and profuse. Flap congestion is occasional and necrosis is rare. It tolerates stretching, folding, and twisting.
Flap donor area morbidity is negligible. Primary wound closure is always possible. The parotid duct opening is not obstructed. By chance if the opening is injured or obstructed it is of no consequence.  No adverse effect of harvesting the buccinator muscle, particularly on mastication, oral continence, and mouth opening has been observed.
Occasionally the flap pedicle needs to be divided when it obstructs the third molar occlusion. If it is necessary, the division of the pedicle is usually a minor procedure which can be performed at outpatient under local anesthesia or day care under short general anesthesia. Folded part of the pedicle does not require deepithelization, as the opposing epithelized surfaces fuse well with the passage of time. No epithelial cyst formation is encountered in the infolded flap pedicle, or in the tunneled part of the flap.
Midface growth patterns have not been assessed in this series and therefore cannot be commented. However, it has been noticed that tension free complete two layer closure of the palate and avoidance of radical dissection in the maxillary tuberosity area are important factors for avoiding disturbance in maxillary growth and dentition. 
Buccal myomucosal flap is a dependable flap with well-defined neurovascular supply. Bilayered total closure of the palate without tension and raw area, proper placement of reconstructed levator muscle sling, and effective lengthening of soft palate are possible in the repair of widest CP or large fistula. Knowledge of flap anatomy and technique of flap transfer and its insetting are required for success of this technique.
| Acknowledgement|| |
I sincerely and respectfully acknowledge the help and support given by Dr Ian T Jackson, Dr Mukund Reddy, Dr Prabha Yadav, and Dr Satish Arolkar. I appreciate Dr Nilesh Trivedi and Dr Monali Mankadia for the help.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2]