Midface and Palatomaxillary Reconstruction Treatment & Management

For most palatomaxillary defects, surgical therapy involves, at a minimum, split-thickness skin graft coverage of any significantly denuded areas of buccal soft tissue. This reduces contraction and speeds wound healing. Options at that point include intraoperative modification of an obturator by a skilled prosthodontist versus composite reconstruction. ^[2] In most cases, this includes osteocutaneous free tissue transfer consisting of either fibula, radius, or scapula osteocutaneous free flap placement. ^{[3, 4, 5, 6, 7, 8, 9, 10]} The details of these procedures are beyond the scope of this article, but appropriate references can be found in the References section.

Advantages of free tissue transfer include immediate reconstruction, closure of the oncologic defect, and potential to place osseointegrated implants to support dental and/or facial implants. However, the need for postoperative adjuvant radiation therapy often modifies the ability to place osseointegrated implants.

The drawbacks to free tissue transfer include second-site surgery, prolonged operating room time, and a long period of wound healing prior to the resumption of oral intake.

Obturator placement is likely to be more successful in patients with less than 50% hard palate defect. ^[2] Further, the presence of dentition makes obturator retention much more stable by allowing placement of clasp units to residual dentition. The advantages of obturation include shorter operative time, near immediate resumption of oral intake, no need for second surgical site, ability to remove the prosthesis and directly inspect potential sites of recurrence, patient acceptance of oral prostheses (especially in the denture wearer), and the ability to modify the prosthesis in the clinic. The drawbacks include the need for a skilled prosthodontist, ongoing prosthetic modification, and the need to remove and clean the prosthesis.

A retrospective study by Swendseid et al indicated that in upper facial and midfacial free flap reconstruction, optimizing pedicle orientation often involves strategies such as vascular grafting and using more distal branches of the facial system as recipient vessels for revascularization. Out of 295 such reconstructions, including 108 bony and 187 soft tissue, the ipsilateral neck was reached by the vessels in 82% of cases, allowing them to be anastomosed to traditional target vessels. Two percent of reconstructions required arterial grafts, and 7% required venous grafts. Thirteen percent of cases involved selection of alternate recipient vessels, including the superficial temporal vessels, distal facial branches (accessed through a separate facial incision), and angular vessels. The investigators also found an association between vein grafting and a greater flap failure rate. ^[11]

In both the patient with trauma and the patient with cancer, the surgeon must adequately assess the anticipated defect and identify sufficient sources of composite tissue for palatomaxillary reconstruction. This requires Allen testing of the nondominant forearm, usually, or duplex ultrasound of the bilateral lower extremities, if fibula free tissue transfer is planned. These tests are both required to identify possible vascular compromise that risks both flap and donor extremity injury.

Many questions currently surround the indications for primary reconstruction versus creation of an obturator. In some cases, both approaches might be indicated. The current considerations that must be addressed prior to deciding on the optimal reconstructive approach include the following:

• General medical condition of the patient

• Margin status and the possible need for postoperative adjuvant therapy

• Patient desires

• Size of the surgical defect

• Status and availability of remaining dentition

• Availability and experience of the microvascular surgeon and/or prosthodontist

Some have argued that obturation allows direct inspection and earlier identification of high-risk recurrent disease. ^[2] However, this, in and of itself, is not a sufficient reason to use an obturator and to not perform reconstruction. In cases in which the operative site and regions of potential recurrence are not exposed, these patients continue to be followed for signs and symptoms of recurrence, and directed imaging studies (CT scanning or MRI) are effective at identifying potential recurrent disease.

In the patient undergoing obturation, preoperative creation of a dental and palatal mold can help with the intraoperative creation of the obturator. Not only does this provide a template upon which the obturator can be added, but it also allows the preoperative identification of points of dental fixation of the obturator. Thus, the preoperative involvement of an experienced prosthodontist is essential.

The primary intraoperative concern is complete and successful resection of the primary tumor. Reconstruction cannot proceed unless the surgeon is confident in the gross total resection of tumor. Additional intraoperative findings can suggest the indication for postoperative radiotherapy in the case of residual disease or close margins. Following complete tumor resection, the decision to pursue free tissue transfer reconstruction versus obturation depends on the factors noted above (see Preoperative Details).

A team-based approach with both an experienced microvascular surgeon and prosthodontist available at the time of the resection aids in determining the most appropriate next step in management. ^[12] Free tissue transfer donor sites are chosen based on the size and geometry of the resulting defect. The fibula harvest site can provide significant amounts of bone stock but provides a smaller soft tissue paddle. Further, the ability to create multiple osteotomy sites in the fibula donor bone stock allows contouring of the osteocutaneous site to the corresponding defect.

The radial forearm osteocutaneous site can provide up to 7 cm of bone, but this tends to be less robust and does not accommodate osseointegrated implants. Lastly, the scapula donor site can provide an intermediate amount of bone stock with options for harvesting larger, complex cutaneous donor tissue.

In the case of obturation, the previously created dental appliance can be subsequently molded and shaped to the defect intraoperatively and then reduced in the clinic as the defect contracts. Lastly, once an adequate appliance has been created, the cavity is obliterated with Xeroform gauze or a similar material, and the obturator is secured in place with a single screw through the residual hard palate. Care must be taken to ensure that this screw can be removed in the clinic in an awake patient to prevent unnecessary return to the operating room.

In the case of free tissue transfer, the postoperative management is much more complex than that in patients who have undergone obturation. The authors anticipate a 5-day hospital stay, during which every 4 hours the flaps are checked by the physician team for the initial 48 hours and then twice daily during the following 3 days. The authors use implanted Doppler probes to determine arterial inflow into the flap and determine venous competence based on the gross appearance of the flap and, occasionally, bleeding after puncture of the skin paddle with an 18-gauge needle. Antibiotics that cover oral flora are continued for 48-72 hours. Depending on defect size, oral intake is delayed for 1-2 weeks and, in the interim, nutrition is delivered via nasogastric feeding.

Following placement of a surgical obturator, patients are fed immediately following surgery. The inpatient stay is typically limited to 24 hours unless other indications exist for inpatient management. The patient is usually seen by the prosthodontist within the first 3-4 weeks. The obturator is removed along with any packing material in the clinic, and the obturator is modified. The defect is expected to begin to progressively contract at this point, and the obturator can be reduced in size during this and subsequent visits.

Regardless of the method of defect closure, the immediate postoperative visit must be used to confirm adequate oncologic control and, if indicated, be focused around adjuvant therapy planning for adequate cancer management.

See Postoperative Details.

Flap failure represents the most serious complication of free tissue transfer. This should occur in fewer than 10% of cases, and, in many experienced surgeon’s hands, fewer than 5% of patients experience flap failure. Given the gross violation of both the oral and sinonasal cavities, wound infections occur infrequently. These can be handled in most cases with local wound care or antibiotic treatment. ^[3]

Controversy currently exists regarding which patients/defects to reconstruct with primary microvascular free tissue transfer versus obturation or a combination of both strategies. ^{[2, 12]} At the authors’ institution, patients with large defects (> 50% of the hard palate) generally benefit from free tissue transfer. Patients without residual dentition, elderly patients who have limited life expectancy, or those who prefer obturation over free tissue transfer are reconstructed with an obturator. ^[13]

Another controversial question that arises is whether or not to place osseointegrated implants in patients requiring adjuvant radiotherapy after fibula free tissue transfer. ^[2] Further, the timing of osseointegrated implant placement has been debated. At the authors’ institution, we typically delay implant placement at least 12 months after completion of adjuvant radiotherapy. Some authors have advocated concurrent hyperbaric oxygen therapy to reduce the risk of osteoradionecrosis following the placement of osseointegrated implants.