Achieving adequate margins in ameloblastoma resection: the role for intra-operative specimen imaging. Clinical report and systematic review.

BACKGROUND: Ameloblastoma is a locally aggressive odontogenic neoplasm. With local recurrence rates reaching 90%, only completeness of excision can facilitate cure. Surgical clearance has widely been based on pre-operative imaging to guide operative excision margins, however use of intra-operative specimen x-ray or frozen-section has been sought to improve clearance rates, and advanced imaging technologies in this role have been proposed. This manuscript aims to quantify the evidence for evaluating intra-operative resection margins and present the current standard in this role. METHOD: The current study comprises the first reported comparison of imaging modalities for assessing ameloblastoma margins. A case is presented in which margins are assessed with each of clinical assessment based on preoperative imaging, intra-operative specimen x-ray, intra-operative specimen computed tomography (CT) and definitive histology. Each modality is compared quantitatively. These results are compared to the literature through means of systematic review of current evidence. RESULTS: A comparative study highlights the role for CT imaging over plain radiography. With no other comparative studies and a paucity of high level evidence establishing a role for intra-operative margin assessment in ameloblastoma in the literature, only level 4 evidence supporting the use of frozen section and specimen x-ray, and only one level 4 study assesses intra-operative CT. CONCLUSION: The current study suggests that intra-operative specimen CT offers an improvement over existing techniques in this role. While establishing a gold-standard will require higher level comparative studies, the use of intra-operative CT can facilitate accurate single-stage resection.

Total scalp reconstruction with bilateral anterolateral thigh flaps.

Large scalp defects can require complicated options for reconstruction, often only achieved with free flaps. In some cases, even a single free flap may not suffice. We review the literature for options in the coverage of all reported large scalp defects, and report a unique case in which total scalp reconstruction was required. In this case, two anterolateral thigh (ALT) flaps were used to resurface a large scalp and defect, covering a total of 743 cm(2). The defect occurred after resection and radiotherapy for desmoplastic melanoma, with several failed skin grafts and local flaps and osteoradionecrosis involving both inner and outer tables of the skull. The reconstruction was achieved as a single-stage reconstruction and involved wide resection of cranium and overlying soft-tissues and reconstruction with calcium phosphate bone graft substitute, titanium mesh, and two large ALT flaps. The reconstruction was successfully achieved, with minor postoperative complications including tip necrosis of one of the flaps and wound breakdown at one of the donor sites. This is the first reported case of two large ALT flaps for scalp resurfacing and may be the largest reported scalp defect to be completely resurfaced by free flaps. The use of bilateral ALT flaps can be a viable option for the reconstruction of large and/or complicated scalp defects.