What is important for confirming negative margins when resecting mandibular ameloblastomas?

Publication date: Available online 24 November 2016
Source:Journal of Oral and Maxillofacial Surgery
Author(s): Zachary S. Peacock, Yisi D. Ji, William C. Faquin
PurposeThe purpose of this study was to assess the utility of intraoperative radiographs and frozen sections in achieving negative margins and preventing recurrence of mandibular ameloblastomas.MethodsThis was a retrospective cohort study of patients who underwent resection (≥ 1cm) of mandibular ameloblastomas between 2005 and 2015. Subjects were included if they had ≥ 1-year follow-up and complete records. Demographic variables include age, gender, and type of resection (segmental vs. marginal). The predictor variables were type of margin assessment: 1. frozen section 2. intraoperative ex-vivo specimen radiograph 3. both or 4. none. The outcome variables were final margin status and recurrence rate. We also determined the accuracy of intraoperative radiographic margins by comparing to histologic margin distance. Descriptive statistics were conducted with Fisher's exact test.ResultsThe study sample consisted of 35 subjects (47.5 ± 20.4 years, 16 males) who underwent 25 segmental and 10 marginal resections. Ten had frozen sections only, 3 had ex-vivo specimen radiographs only, 10 had no intraoperative measures, and 12 had both. There were no positive frozen sections. One subject had a positive posterior bony margin on final pathology despite negative frozen section histology. There was no difference in recurrence rate at latest follow-up between cohorts.The anterior radiographic margin was 11.8 ± 5.9 mm compared to 11.5 ± 7.5 mm by histology (p=0.124). The posterior radiographic margin was 12.3 ± 5.3 mm compared to 9.8 ± 6.5 mm histologically (p=0.546). Margin distances that were ≥ 5mm when measured with specimen radiographs had histologic margin distances ≥ 5 mm in 25/30 (83.3%) resection margins.ConclusionResection of ameloblastoma with planned ≥ 1cm margins is sufficient to prevent recurrence of ameloblastoma. Achieving a radiographic margin of ≥ 5 mm provided a histologic margins of ≥ 5 mm 83.3% of the time.



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