Long-term evaluation of bone mass in free fibula flap mandible reconstruction.

BACKGROUND: Vascularized fibula transfer has become a preferred method of mandibular restoration after oncologic surgical ablation. In order to elucidate the long-term effect on fibular mass after mandibular reconstruction, change in fibular height was utilized as an indirect measure of change in bone mass over time. Other potentially influential factors in long-term bone mass preservation were evaluated; these included site of reconstruction (central, body, ramus), patient age, length of follow-up, adjuvant radiotherapy, and the delayed placement of osseointegrated dental implants.
METHODS: A retrospective analysis of patients undergoing free fibula mandible reconstruction for oncologic surgical defects between 1987 and 1993 was performed. Postoperative panorex examinations were used to evaluate fibular height and bony union after osteotomy. Fixation hardware was used as a reference to eliminate magnification as a possible source of error in measurement. Only patients with at least 24 months follow-up were included in this study.
RESULTS: There were 27 patients (15 males and 12 females) with a mean age of 43 years (range 14 to 65) included in this study. Mandibular defects were anterior (16) and lateral (11). There were between two and five segmental osteotomies per patient (excluding the ends of the graft). Thirty percent of patients had delayed placement of osseointegrated dental implants. Initial panorex examinations were taken between 1 and 9 months (mean 2) postoperatively. Follow-up panorex examinations were taken 24 to 104 months (mean 54) postoperatively. The bony union rate after osteotomy was 93%. Comparative measurements of fibular height revealed that central segments underwent a mean decrease in height by 4% (range 0% to 22%); body segments decreased in height by 7% (range 0% to 33%); ramus segments decreased in height by 5% (range 0% to 15%). In each anatomic segment, fibular height varied by 10% or less when compared with respect to patient age, length of follow-up, adjuvant radiation therapy, and the presence of osseointegrated dental implants.
CONCLUSIONS: We conclude that the retention of fibula height seen in this study indicates that fibula bone mass is preserved after free flap mandible reconstruction. Furthermore, these findings are not affected by the site of reconstruction, patient age, length of follow-up, adjuvant radiation therapy, or presence of osseointegrated dental implants. This study further supports the efficacy of vascularized fibula grafts for mandible reconstruction.