The role of computed tomography in the preoperative assessment and follow-up of oromandibular reconstruction with microvascular osteomyocutaneous free flaps.

Objective: To investigate the capacity of helical CT in the pre- and post-operative management of oromandibular reconstruction of patients with oropharyngeal carcinoma using microvascular composite free flaps.
Materials/methods: Thirty-four patients with oropharyngeal cancer were examined by helical CT and nine (six men and three women) submitted to oromandibular reconstruction. The osteomyocutaneous flaps used for reconstruction were taken from the iliac crest in six cases and from the fibula in three cases. All patients were examined by CT 1 - 4 days postoperatively and then at 6 monthly intervals. Double helical scans were performed in all cases, with slices of 2 - 3 mm for primary lesion studies and 5 mm for lymph node staging, pitch >/=1 and RI=1. Multiplanar (MPR) and 3D reconstructions were obtained from pre- and postoperative CT examinations.
Results: Preoperative CT showed massive bone infiltration in six of the nine surgical patients and marginal infiltration in three. These findings were confirmed histologically. There were no false negatives. The immediate postoperative examination showed correct flap positioning in eight of nine cases. The flap underwent ischemic necrosis in two cases; CT showed very early signs of bone ischemia in both. CT detected two cases of recurrence after about 1 year.
Conclusions: Axial CT permitted adequate assessment of the extent of mandibular infiltration and detected early ischemic complications and distant recurrences. Integration with MPR and 3D reconstructions simplified the choice of flap type and size and enabled the postoperative assessment of correct flap positioning. This helped the surgeon plan subsequent rehabilitation with osseo-integrated implants.