Palatal Fistula



Palatal Fistula


Gregory D. Pearson





ANATOMY



  • The Pittsburgh fistula classification system classifies fistulas as I to VII, from a posterior to anterior location on the palate4 (FIG 1).



    • Type I involves only the uvula (consisting of a bifid uvula).


    • Type II involves the soft palate.


    • Type III occurs at the junction of the hard/soft palate.


    • Type IV arises within the hard palate.






      FIG 1 • Pittsburgh fistula classification system.


    • Type V is located at the incisive foramen (reserved for Veau IV clefts).


    • Type VI is a lingual alveolar communication on the alveolus.


    • Type VII is located on the labial side of the alveolus.


PATHOGENESIS



  • Occurrence rates of palatal fistula vary from 0% to 60% in reported literature.1,2,3


  • Several factors have been associated with the prevention of palatal fistula:



    • Tension-free and watertight closure



      • Relaxing incisions advocated by von Langenbeck for tension-free closure.


      • Jackson et al. proposed “CHOP modification” of Furlow palatoplasty for soft palate repair.2


    • Complete two-layer closure of nasal and oral flaps



      • LaRossa promoted liberal use of vomer flaps for closure of the nasal floor.5


    • Infection prevention



      • The use of perioperative antibiotics is debated in the literature.


NATURAL HISTORY



  • Palatal fistula will remain patent until the time of closure.


  • A fistula can be symptomatic or asymptomatic


PATIENT HISTORY AND PHYSICAL FINDINGS



  • Palatal fistula can occur after cleft palate repair, oncologic resection, trauma, or illicit drug use.


  • Patients may report that the fistula is symptomatic.



    • Nasal escape of food or liquids



      • May be intermittent


      • Typically, viscous liquids like yogurt


    • Nasal escape of air



      • May be noted by patient as change in voice


  • May be noted by speech pathologist as nasal turbulence or hypernasality


  • Physical examination will demonstrate a hole or communication from the oral to nasal cavity.



    • Fistulas can range from small to large and vary in location on the palate.


    • Small fistulas can be difficult to see, but the patient can typically state/point to the location.



      • An examination under anesthesia with a lacrimal probe can be useful to determine the location, size, and orientation of a fistula.



    • A dental mirror can be useful in evaluating anterior fistulas.


    • Deep crevasses or folds of mucoperiosteal tissue can simulate a fistula.


    • Palatal expansion may open an occult fistula that was already present.


IMAGING



  • Radiographic fistulograms (such as those performed for an enterocutaneous fistula evaluation) are not necessary.


  • Physical examination should determine whether a fistula is present.


  • Nasopharyngoscopy or video fluoroscopy should be employed to determine velopharyngeal gap size in patients with fistula and velopharyngeal dysfunction.




NONOPERATIVE MANAGEMENT



  • Obturators/dental retainers can be fabricated by dentists or orthodontists to provide symptomatic relief (FIG 2).



    • Obtaining patient compliance for wearing the retainer can be difficult.


    • The dental brackets on the retainer may loosen and require retightening or fabrication of a new splint.


    • The patient must have enough teeth to properly support a retainer.


SURGICAL MANAGEMENT



  • Surgical management and operative options are largely dictated by the location of the palatal fistula based upon the Pittsburgh classification system.


  • When determining whether to repair a fistula, the surgeon should strongly consider and assess whether the fistula is symptomatic.



    • Nasal escape of fluids or foods, hypernasality, and preventing further surgical or orthodontic interventions (eg, bone grafting or orthognathic surgery) are all reasons for attempted fistula repair.


  • Pittsburgh type I



    • Bifid uvula rate ranges from 1.34% to 19% of selected populations, but the true fistula rate is probably underestimated in the literature.


    • Because these fistulas tend to be asymptomatic as well as concerns about anesthesia on pediatric brain development, these fistulas are the least likely to be repaired as a primary objective for an operation.






      FIG 2 • Palatal fistula (A) covered with an obturator (B).


  • Pittsburgh type II



    • When determining the type of reconstruction choice for a soft palatal fistula repair, a surgeon should also make a determination related to a child’s resonance (specifically if VPD is present) and the type of previous repair performed.



      • If the child has VPD, the fistula may be fixed but hypernasality will likely persist unless addressed with the repair.


    • If a child has normal resonance regardless of the type of primary palatoplasty performed, augmentation/reinforcement with acellular dermal matrix (ADM) can be used.6


    • For patients with a fistula after straight-line repair and concurrent VPD, addressing the VPD with either a palatal lengthening procedure or VPD surgery should be strongly considered.



      • A conversion to a Furlow double opposing Z-plasty typically allows repair of a type II fistula while addressing VPD in children with small velopharyngeal gaps on imaging.7


      • The CHOP modification with bilateral relaxing incisions can facilitate tension-free closure.


    • For larger velopharyngeal gaps and fistula or very large fistula (dehiscence), a superiorly based posterior pharyngeal flap may be necessary as conversion to Furlow may not lengthen the palatal sufficiently.


  • Pittsburgh type III



    • Traditional teaching reports that the junction of the hard palate and soft palate remains the most common site of fistula, particularly when employing a Furlow palatoplasty.


    • As for type II fistula, the patient’s resonance and type of previous repair should influence the operation considered for fistula repair.


  • Pittsburgh type IV



    • There is significant overlap for techniques used to repair type III and IV palatal fistulas.


    • The mucoperiosteal flaps tend to scar, become stiffer, and have less mobility compared to flaps used in a primary palatoplasty, thus limiting their advancement or rotation potential.


  • Pittsburgh type V



    • This is the second most common location of fistula as well as the most challenging to repair given the relative lack of palatal tissue in this area.


    • These fistulas are often the result of either poor inset of the lateral palatal mucoperiosteal flaps into the premaxillary segment or more commonly a premaxillary segment that is so anteriorly displaced out of the arch (a “locked out” premaxilla and intentional fistula) that closure at the time of initial palatoplasty is not possible.



  • Pittsburgh type VI and VII fistulas pertain to the alveolar arch and labial sulcus and are addressed in the chapter on alveolar cleft repair.


Preoperative Planning



  • The surgeon must discuss the possibility of palatal fistula recurrence after attempted closure with the patient and family.


  • Assuring proper patient compliance with postoperative instructions prior to embarking upon repair is imperative.


  • Depending on the type of repair technique used, a surgeon may consider having orthodontist fashion of a postsurgical retainer to protect repair while healing, particularly for type IV and V fistulas.



    • It is important to ensure the retainer does not put pressure on flaps or area of repair while still protecting the surgical site from tongue and food particulate.


  • As previously stated, in rare instances, an examination under anesthesia with a lacrimal probe can be useful to determine the location, size, and orientation of a fistula.


  • If a local flap is used, it must be protected from masticatory trauma during healing.


Positioning



  • The patient should be orally intubated.



    • May use a regular endotracheal tube or oral RAE endotracheal tube depending upon surgeon and anesthesiologist’s preferences.


    • The endotracheal tube may be positioned in the midline or laterally depending on the repair technique chosen.


  • Typically, the patient should be placed in a horseshoe headrest with a shoulder roll and slight extension of the neck.


  • A Dingman mouth prop or dental bite blocks (in which use depends on surgical technique to be employed) can be extremely useful for proper exposure of the intraoral cavity.


Approach



  • Although multiple strategies can be performed for each site, the most common/useful approaches will be addressed according to the Pittsburgh classification system.


  • Pittsburgh type I: Excision and reapproximation


  • Pittsburgh type II:



    • Lateral relaxing incisions and rerepair



      • May consider augmentation with ADM


    • Conversion by Furlow palatoplasty


    • Posterior pharyngeal flap


  • Pittsburgh type III:



    • Lateral relaxing incisions and rerepair



      • May consider augmentation with ADM


    • Posterior pharyngeal flap (if VPD present)


    • Buccal myomucosal flap


    • Facial artery musculomucosal (FAMM) flap


  • Pittsburgh type IV:



    • Lateral relaxing incisions and rerepair with pushback technique



      • May consider augmentation with ADM


    • Elevation of mucoperiosteal flaps and pushback technique


    • Labial mucosal flap



      • If space in dental arch to pass through or if bite blocks employed


    • Buccal myomucosal flap


    • FAMM flap


    • Tongue flap


    • Free tissue transfer


  • Pittsburgh type V:



    • Labial mucosal flap


    • FAMM flap


    • Tongue flap


    • Premaxillary turnover flap



      • Primarily used as nasal lining flap for fistula at anterior incisive foramen in Veau IV cleft


    • Free tissue transfer