Palatal flap in bilateral inferior partial maxillectomy

Abstract

Maxillectomy is done for a variety of disease conditions. Reconstruction following maxillectomy is done to restore the form and function. One of the important goals that are to be achieved in reconstruction is the separation of the oral and nasal cavities. In this article, we report the use of palatal flap by preserving the descending palatine artery during bilateral inferior partial maxillectomy, for separating the nasal cavity from the oral cavity. This technique eliminates the need for an obturator or another free or local flap for this purpose.

Background

Benign tumours, malignant tumours, osteomyelitis of fungal origin are some of the pathologies of the maxilla that require surgical resection of maxilla to varying extents. There are different classifications of maxillectomy¹ mostly based on the extent of loss along with the vertical, horizontal and transverse directions. Reconstruction following maxillectomies is quite a difficult task as multiple facets need to be addressed.² Being present in an area of the body where aesthetics is a primary concern, restoration of form is of great importance. The functional aspects associated with maxilla are not simple either to be left behind. There is mastication, deglutition and speech which are so complex whose restoration needs meticulous planning and precise execution. Obturators, titanium mesh, free and pedicled soft tissue and hard tissue flaps have been employed in various combinations to restore the form and function. The three-dimensional aided reconstructions using free fibula flap with dental implants have been found to have a higher quality of life index and a good degree of patient acceptance.^{3 4} Achieving a good barrier between oral and nasal cavities, thereby preventing nasal regurgitation during deglutition is one of the primary goals of reconstruction. This barrier also helps in the restoration of speech.

Just as important the meticulous planning of reconstruction is, planning the resection must take equal consideration. Some authors believe that a more conservative resection improves the quality of life irrespective of the kind of reconstruction done.⁵ When trying to be conservative, though the nature and extent of disease play a major role in planning the resection, expertise in the form of anatomical knowledge and surgical acumen can yield a subtle variation in the resection producing an amplified result in the outcome of the reconstruction.

Case presentation

A 30-year-old man presented to the outpatient department with multiple mobile teeth in the upper jaw with discharge in the gums for 1 month. He had undergone a root canal treatment for one of his right upper premolars at another centre following which the tooth had become very loose and he was then referred to a higher centre for further management. He was a diabetic but non-compliant with the treatment. Examination of the oral cavity revealed multiple sinus openings with discharge in the attached gingiva of the upper jaw. The anterior maxilla was mobile and almost all of his teeth in the upper right quadrant were mobile. There were no carious teeth.

Considering his immunocompromised status and the clinical presentation, he was provisionally diagnosed to be suffering from osteomyelitis of maxilla probably of fungal origin.

Investigations

The patient had elevated blood sugar levels: fasting 165 mg/dL, postprandial 210 mg/dL and glycated haemoglobin of 7.9%. Remaining laboratory investigations were within a normal range.

Initial biopsy and culture of the tissue specimen from the canine region of the right maxilla revealed fungal osteomyelitis with occasional ill-defined granulomata and broad aseptate fungal hyphae morphologically resembling mucormycosis (figures 1 and 2). However, the culture was negative for fungus.

Figure 1.

Pictomicrograph showing evidence of osteomyelitis.

Figure 2.

Pictomicrograph showing evidence of fungal hyphae morphologically resembling mucormycosis.

The contrast-enhanced CT scan of the head and neck region revealed evidence of bony erosion of the maxilla on both sides extending along the entire anteroposterior extent.

Treatment

We discussed the treatment plan in a multidisciplinary team conference and the patient was advised to undergo two-staged surgical treatment with bilateral inferior partial maxillectomy and anti-fungal therapy with a delayed reconstruction with free fibula flap to avoid jeopardising the flap due to fungal infection. Although the first stage of surgery which was bilateral inferior partial maxillectomy required reconstruction to separate the nasal cavity from the oral cavity. With the available information from the CT scan, we planned to preserve the mucoperiosteal flap of the hard palate which could be used as a partition between the oral and nasal cavities (figures 3 and 4). Maxillectomy was modified to preserve the descending palatine artery (DPA) to maintain the palatal mucoperiosteal flap viable. Early in the operation, polyvinyl acetate nasal packs were placed into the nasal cavity on either side. The approach to the maxillectomy was intraoral through a long curved incision in the upper vestibule and through a crevicular incision, at the buccal and palatal aspects of the upper alveolar arch, respectively. The palatal mucoperiosteum was stripped off up to the junction of the hard and soft palate.

Figure 3.

Evidence of osteomyelitis of the entire hard palate in the transverse aspect.

Figure 4.

Anteroposterior and vertical extent.

Modification

During the lateral nasal wall osteotomy with the single guarded chisel on both sides, we stopped short of the posterior wall of the maxilla to prevent the dissection of the DPA in the greater palatine canal (figure 5). The other osteotomies of the anterior and posterior walls of the maxilla and the nasal septum were done as usual. After pterygomaxillary disjunction, the osteotomised maxilla was down fractured. With the palatal mucoperiosteum already stripped off and the maxilla down fractured, the artery could be seen emerging out of the greater palatine foramen (figure 6). The artery was then carefully de-canalised by cutting open the posterior medial wall of the canal on both sides with a rotating bur and bone nibbler. Finally, the osteotomised inferior maxilla was removed with intact mucoperiosteum of the hard palate along with its blood supply (figure 7). The maxillary antral mucosa was completely excised on both sides. The bilaterally based palatal flap was sutured to the vestibular mucosa in entirety thus, enabling to separate the nasal and oral cavities. With the nasal packs in situ, the patient was extubated on table after ensuring that there was no postnasal bleeding.

Figure 5.

Greater palatine canal with descending palatine artery bilaterally.

Figure 6.

Bilateral greater palatine foramen.

Figure 7.

Intraoperative picture showing resected inferior maxilla and preserved bilateral palatal flap with descending palatine artery posteriorly.

Outcome and follow-up

The postoperative course was uneventful. The nasal packs were changed after 72 hours and removed on the 5th postoperative day. There was a minimal anterior nasal drip that eventually ceased in a few days with conservative methods. The flap healed well (figure 8). Since the native tissues (the mucoperiosteum) were used to maintain the integrity of the oral cavity, the primary function of the partitioning of the oral and nasal cavities was maintained. This became evident in the absence of nasal regurgitation on taking liquids and soft solids. Thus, the need for an obturator was obviated. This also underscores the fact that the integrity of the velopharyngeal sphincter remained intact. However, in the absence of the underlying palatal bony support, the ancillary function of assisting the tongue in the propulsion of food bolus towards the oropharynx was expectedly compromised. At 2 weeks postoperatively, he was swallowing liquids and semisolid diet without nasal regurgitation. He had an intelligible speech with an altered nasal twang. The loss of teeth had a telling on his facial profile and the masticatory function The patient was started on antifungals with injection lipid amphotericin B. The reconstruction with free fibula flap and implants are planned as a second stage surgery as per the patient’s desire.

Figure 8.

Healed posteriorly based palatal flap after bilateral inferior maxillectomy at 2 weeks postoperative.

Discussion

Palatal flaps are used for the reconstruction of defects arising mostly in the oral cavity.⁶ The most common purpose for its use is that it acts as a barrier. Be it for an oroantral communication or oronasal communication, it serves as a good barrier. The posteriorly based palatal flap is used for closure of oroantral communications and it derives its vasculature from the ipsilateral greater palatine artery (GPA).⁷ Oronasal communications arising because of tumour excision are also closed with the palatal flap from the contralateral side and Jung et al proposed a technique of delayed closure after secondary healing had occurred.⁸ Molumi et al described that the ipsilateral mucoperiosteum can be viably preserved after stripping it off and then resecting the bony component of the maxilla, even if the ipsilateral GPA is sacrificed. In such cases, the GPA from the contralateral side would vascularise the flap across the midline. This flap has been used to separate the oral and nasal cavities when unilateral maxillectomy is done.⁹ Omura et al described anterior pedicled inferior turbinate flap in conjunction with palatal flap for standard inferior maxillectomy with hard palate resection. In this case, the anterior hard palate was resected leaving behind the posterior part, which houses the greater palatine canal and foramen thus preserving the GPA.¹⁰ However, there is no literature, which describes the use of palatal flap for oronasal separation after a bilateral inferior partial maxillectomy involving both greater palatine foramens, since bilateral maxillectomy is expected to lead to the devascularisation of the mucoperiosteum of the hard palate. A study on cadavers by Oliver et al has described the use of palatal flap for base of the skull reconstructions but not for oronasal separation.¹¹ The usage of palatal mucoperiosteum as a flap has always been limited due to its pivot point in the posterior part of its bony component of the hard palate. The greater palatine foramen in the posterior part of the hard palate is the conduit through which the DPA exits to continue as the GPA, the major blood supply to the flap. Thus, the bilateral inferior partial maxillectomies, especially for the malignancies, include the excision of the palatal mucoperiosteum along with the bony hard palate necessitating either an immediate flap reconstruction or an obturator for the oronasal separation.

In the present case, the entire mucoperiosteum of the hard palate was preserved by stripping it off the hard palate. While performing the osteotomy of the lateral nasal walls with the chisel, utmost care was taken to stop short of the posterior end to preserve the traversing DPA. This is well explained by Li et al in their extensive study, which they published in their article about the relationship of DPA to the Le Fort I osteotomy of the maxilla to preserve the DPA.¹² The maxilla was then down fractured.

Our modification of the maxillectomy was that, before the osteotomised inferior maxilla was removed, the posteromedial wall of the greater palatine foramen facing the oral cavity was opened on both sides with a rotating bur and then a bone nibbler to de-canalise the DPA from the posterior maxilla (figure 9). The DPA, which is a branch of internal maxillary artery, enters into the posterior wall of maxilla at the pterygopalatine fossa region. It then traverses for a very short distance through the greater palatine canal and exits it through the greater palatine foramen as the GPA (figures 10–12). Since the posterior wall of the canal a very thin shell, it can be easily nibbled off to decanalise the artery. By preserving this artery on both sides, it was possible to preserve the palatal flap and use it for oronasal separation after the removal of the osteotomised inferior maxilla. The palatal flap was sutured to the buccal and labial gingiva thus achieving an oronasal separation. Consequentially, an obturator to achieve the same end was unnecessary. Moreover, fixing an obturator after a bilateral inferior partial maxillectomy would have been exceedingly difficult without implants. The authors did not favour implants or an immediate reconstruction because of the ongoing serious fungal infection. However, a functional oronasal separation after a bilateral modified inferior partial maxillectomy was successfully achieved by using a viable palatal flap.

Figure 9.

Posteromedial wall of the greater palatine foramen marked with arrows which were removed with bur and bone nibbler. (This figure was hand drawn by the author.).

Figure 10.

The stainless steel wire representing the descending palatine artery in the greater palatine canal then exiting through the greater palatine foramen and continuing as greater palatine artery.

Figure 11.

Stainless steel wire representing the descending palatine artery at its point of entry into the maxilla in the pterygomaxillary fissure region.

Figure 12.

A view from the inferior aspect of posterior maxilla, showing the stainless steel wire representing the descending palatine artery entering at the pterygomaxillary fissure region and exiting through the greater palatine foramen.

Patient’s perspective.

I had been having this problem of infection in my upper jaw for more than a month. I had visited other centres for treatment and I learnt that a surgery had to be done to remove my upper jaw. I was informed the shape of my face will be disfigured and I will need a plate in my mouth to prevent food or water from going to my nose. I was also told my speech will be altered. I was referred to this centre, and underwent this surgery. I was told by my doctors that a new technique was going to be followed in doing this surgery. After the removal of my upper jaw, the shape of my face has not changed much. I was very glad that I was able to speak well from the second day after surgery. I am not using any plate in mouth as was told me to prevent food from going into the nose. I am happy with the result of this surgery.

Learning points.

• Preoperative multidisciplinary team planning of the resection is as important as planning of the reconstruction. The team included senior head and neck reconstructive surgeon, dental surgeon, otolaryngorhinology surgeon and infectious diseases consultant.

• Being preservative is not necessarily being conservative but is being innovative while being aggressive. It always improves the outcomes and postoperative quality of life.

• Palatal flaps in bilateral inferior partial maxillectomy for oronasal separation, whenever possible obviates the need for an obturator or a second flap.