Immediate free flap mandibular reconstruction: significance of adequate surgical margins.

The pathologic records of 182 consecutive patients who had mandible resections were reviewed to determine the incidence of positive margins in the bone specimens and the risk factors associated with positive margins. Of the 182 cases reviewed, 82 (45%) were found to have involvement of the mandible at the time of resection and four (2%) were found to have positive margins. The predominant tumor histology was squamous cell carcinoma, 148 of 182 (81%), followed in frequency by osteosarcoma 12 of 182 (7%), salivary gland tumors 13 of 182 (7%), and miscellaneous other tumors (nine of 182 (5%). Of the four tumors with positive margins, two (50%) were squamous cell carcinomas, one (25%) was an osteosarcoma, and one (25%) was a salivary gland tumor. All four tumors were large tumors that had failed to respond to previous therapy. All obviously involved the mandible at the time of presentation. This study demonstrates that the incidence of bone margin involvement after mandibulectomy is rare and predictable and that clinical selection of candidates for immediate reconstruction is reliable in preventing inappropriate use of free bone flaps in patients at risk for positive bone margins.