Revision Surgery of the Cleft Palate

Abstract

Cleft palate repairs often require secondary surgeries and/or revisions for a variety of reasons. The most common causes are symptomatic oronasal fistulas and velopharyngeal insufficiency. Complications from primary surgery, such as wound dehiscence, infection, and hematomas, contribute to the relatively high rate of revision surgery. Prevention of postoperative complications that may lead to fistula or velopharyngeal insufficiency is key, and many techniques have been described that have reportedly decreased the incidence of secondary surgery. Management varies depending on the nature of the fistulous defect and the type of velopharyngeal insufficiency. Numerous surgical options exist to fix this deficiency.

Craniofacial anomalies are among the most common congenital defects, of which cleft palate and cleft lip with or without palate involvement are the most common. In the United States, there are 2,651 cases of cleft palate and 4,437 cases of cleft lip with or without palate involvement annually. ¹ The consequences of orofacial cleft extend beyond cosmetic concerns and include abnormalities in speech, swallowing, and growth. Treatment is typically aimed at early surgical intervention and involves a multidisciplinary approach of otolaryngologists, speech pathologists, orthodontists, audiologists, maxillofacial surgeons, psychiatrists, geneticists, and prosthodontists. ²

Surgical repair of cleft lip and cleft palate is a complex challenge for the plastic surgeon. There are a variety of techniques, each with multiple variations. Outcomes of cleft palate repair are variable, with much debate in the literature regarding the best approach. Unsatisfactory outcomes of cleft palate repair include oronasal fistula and persistent velopharyngeal dysfunction (VPD), which are among the most common indications for revision surgery. Like primary cleft palate repair, there are a variety of techniques for secondary revision surgery. Optimal treatment is dependent on a thorough evaluation to determine the most appropriate surgical approach. In addition to well-established surgical techniques, novel therapies are being investigated with outcomes that are comparable to current standards.

Oronasal Fistula

Revision cleft palate surgeries are most often required due to significant oronasal fistulas. Fistulas occur after wound dehiscence, which can be secondary to closure under tension, infection, flap trauma, hematoma, or tissue ischemia. Fistulas become clinically significant when they lead to nasal air escape, food/liquid regurgitation, speech distortion, or patient discomfort.

Incidence

The incidence of oronasal fistula after primary cleft palate repair has been reported to range from less than 1% to upward of 76%, ^{3 4 5} with an average of 8.6%. ⁶ Incidence appears to have improved significantly over time, with a recent meta-analysis reporting a rate of 4.9%. ⁷ This extreme variation is partially due to the lack of a standard classification scheme for fistulas. One proposed system, the Pittsburgh Fistula Classification System, ⁸ includes seven types—fistulas of the uvula or bifid uvulae (type I); in the soft palate (type II); at the junction of the soft and hard palates (type III); within the hard palate (type IV); at the junction of the primary and secondary palates (type V); lingual-alveolar (type VI); and labial-alveolar (type VII) ( Fig. 1 ). Fistulas are then further categorized into functional or nonfunctional depending on their effect on speech and the presence of nasal regurgitation. Prospective examination and assignment of all fistulas to such a standardized classification scheme are thus key.

Fig. 1.

The Pittsburgh Fistula Classification System for oronasal fistulas.

Fistulas are commonly found within the hard palate, with reported rates approaching 47%. ⁸ In addition, they often form at the junction of the soft and hard palate, the area that is frequently under the most tension at the time of closure. ^{8 9 10 11} Most fistulas are observed in the early stages, within weeks of the original surgery.

Many predictors of postoperative fistula formation have been identified. Several studies attribute fistulas to patient factors (age at primary repair, presence of syndromic condition) or cleft severity (i.e., Veau type, cleft palate versus cleft lip and palate, cleft dimensions). ^{12 13} Increased cleft width and combined cleft lip–cleft palate are often predominant factors. Surgeon experience and technical aspects, such as traumatic dissection, excessive tissue tension, or absence of a multilayered closure, have also been acknowledged as potential causes for failure. ¹³ Interestingly, Swanson et al found that higher rates of fistula formation may occur in adopted children. ¹⁴

Numerous techniques have been proposed that claim to decrease the incidence of oronasal fistula. These include the incorporation of an anterior triangular flap into the standard von Langenbeck technique, ¹⁵ various modifications of the Furlow palatoplasty, the application of fibrin tissue sealant to the repair, placement of an antibiotic oral pack on the hard palate following surgery, ¹⁶ and preoperative nasoalveolar molding. Furthermore, modifications such as hamulotomies, ¹⁷ use of vomerine flaps, ^{18 19} and palatine foraminal osteotomies ²⁰ have all been described as successful in lowering reported fistula rates. Many experts advocate a three-layered palatoplasty, theorizing that the third or middle layer will be essentially free of tension and thus provide additional protection should dehiscence of either mucosal flap occur. Multiple interposition grafts such as Gelfoam (Pfizer), acellular dermal matrix, amniotic membrane allograft, cartilage, bone, and fascia have all been utilized for this purpose. ^{21 22 23 24 25}

Management

Clinical Assessment

A thorough intraoral examination of the fistula is paramount. Using a nasopharyngoscope can allow for clear inspection of the fistula with simple illumination as well as evaluation of soft palate mobility and competency of velopharyngeal closure. To determine its effects on speech, the fistula can be temporarily occluded using dental wax or a palatal plate. If hypernasality diminishes, the etiology of speech dysfunction can be attributed to the fistula, and a period of speech therapy is likely necessary after closure. On the other hand, if the hypernasality persists, additional velopharyngeal surgery may be warranted.

Early postoperative fistulas can be managed conservatively and may eventually close without intervention ( Fig. 2 ). Asymptomatic fistulas should also be treated conservatively. Fistulas may become clinically significant when they lead to nasal air escape, speech distortion, hypernasality, or nasal regurgitation of food. Even very small fistulas, measuring 1 to 2 mm, can cause air leakage and thus speech impairment. ²⁶ Larger fistulas may also progress to VPD and cause speech distortion.

Fig. 2.

Palatal fistulas identified at 2 weeks following primary cleft palate repair have closed without intervention 4 weeks following the initial repair.

Thus, for symptomatic patients, a perceptual velopharyngeal assessment is important. For patients with a normal velopharyngeal mechanism, repair can be performed at any age. The closure of these fistulas should be delayed, if possible, until completion of orthodontic maxillary arch expansion and be combined with secondary alveolar bone grafting if such a procedure is indicated. Any fistula that recurs during palatal expansion can be managed after orthodontic treatment is complete.

For patients with inadequate velopharyngeal function, a nasopharyngoscopic or videofluoroscopic examination and a fistula occlusion test is performed. If improvement is noted, closure of the fistula alone can be performed. In patients with no improvement, a simultaneous velopharyngeal surgical procedure can be considered, such as a Furlow palatoplasty for those with marginal velopharyngeal function or a pharyngeal flap or sphincter pharyngoplasty for those with inadequate velopharyngeal function.

Surgical Planning

Several surgical options exist when planning to repair palatal fistulas. Simple attempts include direct cauterization as described by Obermeyer in 1967, and progressively more invasive techniques include the myriad of local flaps and graft interpositions such as the conchal graft described by Ohsumi et al. ^{27 28 29 30} The larger surgeries utilized for these repairs include regional pedicled vascularized flaps and free tissue transfers.

The location and size of the fistula will frequently dictate the type of repair pursued. As such, the senior author (J.J.R.) utilizes a repair algorithm based on size and location of the fistula ( Fig. 3 ). Isolated fistulas of the soft palate can be directly excised and repaired, often in conjunction with an intravelar veloplasty or a conversion Furlow palatoplasty if there is concurrent VPD. The Furlow palatoplasty is also an option for an oronasal fistula at the junction of the hard and soft palate. ³¹ Fistulas of the hard palate may require significantly more than just direct excision and closure due to lack of malleable local tissue. If small with minimal scarring of surrounding tissue, local transposition flaps based off the greater palatine artery may suffice. However, these frequently provide an inadequate arc of rotation for complete closure of medium-sized or otherwise scarred fistulas. Repair of hard palate fistulas may thus require a full revision palatoplasty that involves complete re-elevation of either unipedicled or bipedicled flaps for complete oral mucosal closure.

Fig. 3.

An algorithm for the management of oronasal fistulas based on location. FAMM, facial artery myomucosal.

Watertight closure of the nasal lining is often more challenging than oral mucosal repair. This is secondary to the inherent friability of the tissues that have been exposed to constant reflux of food contents through the fistula. If local nasal tissue is insufficient, palatally based hinge flaps or nasal septal flaps can be used. ³² Another option is the addition of acellular dermal matrix for augmentation of nasal closure. The rate of recurrent fistulas is reported to be as low as 3.6% with utilization of this adjunct matrix. ^{21 33}

In larger palatal fistulas, healthy, vascularized tissue from other donor sites is preferable. These include Guerrero-Santos and Altamirano's tongue flap and multiple pedicled flaps, such as the facial artery myomucosal (FAMM) flap, both of which can be utilized for larger anterior fistulas ( Figs. 4 and 5 ). ³⁴ The FAMM flap is particularly useful for large fistulas in the anterior palate extending to the mid-palatal region and associated with alveolar clefts. The main disadvantages of such procedures are donor site morbidity, technical difficulty, considerable postoperative care, and need for revision surgery.

Fig. 4.

Guerrero-Santos and Altamirano's tongue flap for the repair of a hard palate fistula. ( A ) Central palatal fistula. ( B ) Anteriorly based pedicled tongue flap for closure. ( C ) Sagittal representation of anteriorly based tongue flap in place.

Fig. 5.

The facial artery musculomucosal flap for the repair of a hard palate fistula.

More recently, the buccal fat pad flap has been advocated for closure of larger hard palate fistulas. The flap is significantly mobile and can easily reach the midline or the lingual central incisors. The well-vascularized tissue epithelializes readily and can be utilized for either nasal or oral closure. It is a straightforward flap to harvest, is reliable, and has minimal donor site morbidity. Moreover, it does not require tunneling or a second operation. ⁷

The use of osmotic tissue expanders has also been described for large anterior palatal fistulas ³⁵ and patients with contracted dentoalveolar arches. In a two-stage procedure, tissue expanders are first placed that recruit local palatal mucoperiosteum; closure then follows. Five patients achieved complete closure, and two had slit-like fistulas closed at time of bone grafting. Finally, patients with extremely large fistulas, history of multiple failed attempts at closure, and/or heavily scarred palates may require free tissue transfer, such as a radial forearm free flap. ³⁶

Obturation is an alternative in symptomatic patients for whom surgical repair is unfavorable. For example, a patient with significant palatal scarring or an older patient who has undergone multiple failed attempts at fistula repair may instead be treated with an obturator. ³⁷ However, some feel that obturators are cumbersome, provide limited symptomatic relief, and can contribute to poor oral hygiene. ³⁸

Prevention of complications cannot be overemphasized. A well-executed primary palatoplasty is the optimal defense against fistula formation. Tension-free closure and adequate postoperative care are crucial. To achieve tension-free closure, the surgeon should use relaxing incisions as necessary, perform a full intravelar veloplasty, completely release the neurovascular bundle with optional osteotomy of the bony foramen, and use meticulous surgical precision to avoid traumatic handling of the mucosal edges. Further release of the tensor aponeurosis from both nasal and oral mucosa and elevation of nasal lining off of the medial pterygoid plates can provide tissue mobility to reach the midline and reduce tension.

Outcomes

Fistulas are difficult to repair definitively, with recurrence rates as high as 96% in some studies, ^{3 4 5 39} though these rates have decreased over time. Importantly, each successive attempt at fistula closure is less likely to be successful. Causes can include a severely scarred palate and wound dehiscence. Interestingly, limited data exists on speech outcomes following fistula repair, but relevant studies report success rates above 60%. ⁴⁰

Velopharyngeal Insufficiency

Velopharyngeal insufficiency (VPI) refers to dysfunction of the velopharyngeal mechanism. There are many causes of VPI, but the most common etiology is a history of repaired or unrepaired cleft palate. ⁴¹ The velopharyngeal mechanism consists of the muscular structures of the soft palate, lateral pharyngeal wall, and posterior pharyngeal wall. It functions as a muscular valve that creates a tight seal between the velum and posterior pharyngeal wall to separate the nasal and oral cavities. Velopharyngeal closure is necessary to achieve normal speech by directing airflow through the mouth instead of the nasal cavity. Hypernasality is generally considered a primary feature of VPI. The velopharyngeal mechanism is also integral to the opening of the eustachian tube. Consequently, patients with VPI may encounter hearing impairment due to the inability to appropriately regulate fluid drainage from the middle ear and equalize pressure across the tympanic membrane. ⁴²

One of the primary muscles involved in the VP mechanism is the levator veli palatini, which functions to elevate and retract the velum against the posterior pharyngeal wall. The levator veli palatini would normally create a sling that is horizontally oriented. In cleft palate patients, there is an aberrant vertical insertion of the levator and no true sling formation. While there are a range of surgical techniques and variations employed in cleft palate repair, the ultimate objectives remain the same—closure of the defect and correction of the position of the soft palate musculature to allow for normal development and production of speech while minimizing the impact on maxillary growth and development. ⁴³ Similarly with VPI surgery the goal is to restore the anatomic ability to be able to form a functional velopharyngeal unit and subsequent improved speech intelligibility.

Incidence

The rate of VPI following primary palate repair requiring secondary surgery ranges from 5 to 29%. ^{44 45 46} There are a variety of factors that must be considered when reporting the incidence of VPI in cleft patients. First, there is currently no standardized assessment for diagnosing and rating the severity of VPI. Moreover, classification of VPI in the literature is inconsistent due to the use of various assessment tools and the widespread reporting of rates attributed only to the number of subjects who underwent secondary surgery.

Diagnosis and rating of VPI severity are largely based on subjective speech assessment, ⁴⁷ which does not accurately predict velopharyngeal closure. ^{48 49} Flexible nasendoscopy is used to evaluate VP closure and function, but there is also a lack of consensus in grading velopharyngeal function via endoscopy. The Golding-Kushner scale was proposed by a multidisciplinary International Working Group in 1990 in an effort to standardize the reporting of multiview videofluoroscopy (MVF) and nasendoscopy in the evaluation of VP function. ⁵⁰ However, studies have demonstrated poor interrater reliability. ^{51 52} Despite these limitations, formal speech assessment and nasendoscopy are critical in diagnosing severity and formulating a treatment plan.

Many studies have identified factors that are associated with VPI following palatoplasty such as age at primary palatoplasty, ^{46 53 54} sex, ⁵⁵ and cleft severity. ^{53 54 55 56 57 58 59} There is an increased incidence of secondary surgery for VPI in patients with increased cleft severity along the Veau hierarchy. Similar to oronasal fistulas, efforts to better define outcome predictors have consistently identified cleft width as a predictor of VPI. Furthermore, patients with higher Veau classification tend to have wider clefts and shorter palates. ⁵⁵ Predictive parameters involving cleft width ratio have demonstrated varying results. ^{60 61}

Management

Speech Assessment

As with any patient, evaluation should begin with a thorough history and physical exam. While previously repaired or unrepaired cleft palate is the most common cause of VPI, other etiologies should be investigated. A formal speech assessment by a speech-language pathologist should precede any surgical procedure. This includes a perceptual speech evaluation to assess for compensatory articulation errors, abnormal resonance, nasal emission, and dysphonia. The Pittsburgh weighted speech score is a tool commonly used to classify velopharyngeal function into one of four categories based on a quantitative scoring system. In order of increasing dysfunction, these categories are competent, borderline competent, borderline incompetent, and incompetent. Further investigation is warranted in patients who are categorized as either borderline incompetent or incompetent. ⁶²

Instrumental Assessment

Further assessment involves visualization of the velopharyngeal mechanism and its closure pattern. There are three main patterns of velopharyngeal closure defined by the primary contribution of each structure to velopharyngeal closure ⁴² :

• (1) Coronal—the primary contribution is the action of the levator musculature elevating and retracting the velum posteriorly;

• (2) Circular—all the structures come together in a “purse-string” movement; and

• (3) Sagittal—the lateral pharyngeal walls move toward the midline.

Nasendoscopy and MVF are the most common diagnostic modalities used to visualize the dynamic function of the velopharyngeal mechanism. Nasendoscopy involves passing a flexible endoscope through the nasal cavity to the posterior pharyngeal wall. Visualization of the velopharyngeal mechanism allows the examiner to determine the size and location of the velopharyngeal gap, and characterize the movement of the velum, lateral pharyngeal wall, and posterior pharyngeal wall during phonation. MVF is used to evaluate the same mechanism from multiple projections: the anterior–posterior view visualizes the contribution of the lateral pharyngeal wall, whereas the lateral view visualizes the contribution of the velum. It is also useful in evaluating children who do not tolerate nasendoscopy. MVF is limited in its ability to measure multiple components of velopharyngeal closure from a single view. Nasendoscopy has also been shown to have a stronger correlation with VPI severity. As a result, MVF is used in conjunction with nasendoscopy when developing a treatment plan. ⁶³

Surgical Planning

Treatment options for VPI include speech therapy, prosthetics, and surgery. Choosing the best course of surgical treatment requires an understanding of the patient's history and mechanics of velopharyngeal closure. The three most common surgical procedures for correcting VPI are Furlow palatoplasty (double-opposing Z-plasty), pharyngeal flap, and dynamic sphincter pharyngoplasty (DSP). Successful surgical correction of VPI is heavily dependent on choosing the appropriate procedure that takes into consideration the patient's pattern of velopharyngeal closure and size of the velopharyngeal gap.

Furlow palatoplasty is appropriate in patients with a sagittal closure pattern and velopharyngeal gap less than 9 mm. In these patients, there is a deficit in posterior velar movement, and lateral pharyngeal wall movement is the primary contributor to velopharyngeal closure. This pattern of closure can be corrected by palatal lengthening achieved with a Furlow palatoplasty. In patients with sagittal closure in whom the velopharyngeal gap is greater than 9 mm, a superior based pharyngeal flap may be used ( Fig. 6 ).

Fig. 6.

Superiorly-based pharyngeal flap for velopharyngeal insufficiency.

DSP is appropriate for patients with a coronal closure pattern and a velopharyngeal gap less than 9 mm. In this closure pattern, there is a deficiency of lateral wall movement and the majority of the closure is due to the contribution of the velum. Because there is poor lateral wall movement, a pharyngeal flap is discouraged due to concerns of airway obstruction. When velopharyngeal gap is greater than 9 mm, Furlow palatoplasty may be combined with DSP. The Furlow palatoplasty provides palatal lengthening in conjunction with the sphincteric motion achieved through DSP. ⁶⁴

Finally, in patients with a circular closure pattern with a velopharyngeal gap less than 9 mm, a Furlow palatoplasty is appropriate. For gaps that are greater than 9 mm, narrow pharyngeal flaps can be used. In these cases, the risk of nasal airway obstruction is minimized by adequate lateral wall mobility. ⁶⁵

Furlow palatoplasty has been shown to be an effective treatment for VPI following primary palate repair with velopharyngeal closure rates of 82 to 89% ^{56 66} and significant improvements in speech assessment scores. ^{66 67 68 69 70} Similar success has been reported with pharyngeal flaps and DSP. Successful correction of VPI with pharyngeal flaps and sphincter pharyngoplasty is reported to be between 74 to 89% and 72 to 85%, respectively. ^{70 71}

Other Treatments

Alternative treatments for VPI to improve outcomes and avoid the risk of airway obstruction associated with pharyngeal flaps and DSP are emerging. ^{72 73} Abdel-Aziz et al reported on the efficacy of a palatopharyngeal sling in treating VPI and its effect on breathing in 17 patients. The sling consists of bilateral myomucosal flaps that are formed from the palatopharyngeus and superior constrictor muscles, passed through incisions made in the soft palate, and then sutured end-to-end on the oral surface of the soft palate. Complete velopharyngeal closure was achieved in 76.5% of patients, and 88.2% experienced improvement in speech. No patients experienced obstructive breathing. ⁷⁴

Posterior pharyngeal fat grafting (PPFG) involves injecting autologous fat into the posterior pharyngeal wall. Lau et al reported an improvement in speech in 73% of patients. However, in the subset of patients who underwent secondary speech surgery, all demonstrated normal speech after PPFG, indicating that it may be a useful adjunctive treatment for patients who suffer from persistent VPI. ⁷⁵ Other novel treatments, such as an AlloDerm (LifeCell Corporation) sling and trans-oral cerclage pharyngoplasty, have demonstrated similar success rates. ^{76 77} However, these treatments have not been widely studied, and current studies are limited by small sample sizes and lack of control groups.

Obstructive Sleep Apnea

The incidence of obstructive sleep apnea (OSA) following pharyngeal flap surgery has been reported to be as high as 93% based on overnight polysomnography performed more than 6 months postoperatively. ⁷² Just over half of these patients were classified as having moderate-to-severe OSA. OSA is more common in pharyngeal flap surgery compared with Furlow palatoplasty, and patients with pharyngeal flaps tend to have more severe forms of OSA. ⁷⁸ Lower rates of OSA have been reported in the literature, but these reports are based on stricter diagnostic criteria that are typically reserved for adult patients and not appropriate in characterizing OSA in children. ⁷⁸

Not all patients who meet criteria for OSA require surgical intervention. Rates of surgical revision for OSA range from 1.8 to 10%. ^{79 80} Many patients experience varying degrees of obstruction in the immediate postoperative period that typically resolves. Surgery is indicated in patients with persistent and excessive chronic airway obstruction that is not responsive to more conservative measures. When appropriate, surgical options are effective in relieving obstruction and include flap division with or without Furlow palatoplasty, port revision, and flap takedown. ^{79 81 82}