Comparing Contour Restoration of Mandibular Body Defects With Fibula, Iliac Crest, and Scapular Tip Flaps: A Conformance Virtual Study.

PURPOSE: The purpose of this study was to determine which of the most commonly used flaps restore contour more accurately in mandibular body reconstructions using conformance analyses and virtual measurements. METHODS: Using normal computed tomography (CT) scans and a 3D software, mandibular body defects were virtually created. "Single shot" and osteotomized fibula flaps (SS-FF and O-FF), iliac crest flaps (ICF) and scapular tip flaps (STF) were digitally harvested and coregistered to reconstruct those defects. Conformance analyses were performed by calculating the root mean square (RMS) for overall and contour conformance. RESULTS: Ten patients normal CT scans were included. The STF demonstrated improved overall conformance compared with the ICF, the SS-FF and the O-FF (RMS = 2.03 mm vs 4.53 mm vs 2.76 vs 2.37 mm, respectively; p<.001). Similar trends were seen for contour conformance in STF compared with the ICF and the SS-FF (RMS = 2.48 mm vs 4.50 mm vs 3.28 mm, respectively), whereas the O-FF performed better than STF (RMS = 1.85 mm vs 2.48 mm; p<.001). CONCLUSIONS: The osseous component of the STF resembles the mandibular body more accurately than the one in the ICF and FF without the need for an osteotomy. Future clinical studies can help to elucidate the clinical impact of these virtual findings.

Predictors of plate extrusion in oromandibular free flap reconstruction.

OBJECTIVES: Plate extrusions after free tissue transfer for mandibular reconstruction can be problematic and generally require revision surgery. Our objective was to assess the predictors of plate extrusion and compare outcomes between fibular free flaps (FFF), lateral border scapular flaps (LBSF), and scapular tip free flaps (STFF). METHODS: Retrospective review of consecutive patients who underwent osseous free tissue reconstruction of the mandible (2008-2014) at Victoria Hospital, London, Ontario. Patient demographics and treatment-related information were collected. RESULTS: We identified 134 procedures and 27 (20.2%) plate extrusions (21/61 FFF, 3/49 STFF, and 3/24 LBSF). Freedom from extrusion after 2 years was significantly associated with the use of FFF (P = .003, HR 6.09 1.82-20.44), performing 1 osteotomy (P = .03, HR 2.61 1.08-6.31), and anterior mandibular defects (P = .01, HR 2.66 1.25-5.66) in the univariate model. FFF's were employed more frequently in younger patients, with 2.4 mm plates, more anterior defects, and with a greater number of osteotomies (P < .001). However, after controlling for these variables in multivariate analyses the use of a FFF was the only significant predictor of extrusion at 2 years (P = .006, HR 3.68 1.46-9.28). CONCLUSIONS: At our institution, use of the STFF predicts mandibular defects that are less prone to developing plate extrusion and FFF tended to be used more frequently in anterior defects with osteotomies. However, after controlling for these factors use of the FFF appeared to have higher rates of extrusion than scapular flaps. Further prospective studies controlling for defect variables are needed to elucidate the risk factors for plate extrusion.

Hydrogel-chitosan and polylactic acid-polycaprolactone bioengineered scaffolds for reconstruction of mandibular defects: a preclinical in vivo study with assessment of translationally relevant aspects.

Background: Reconstruction of mandibular bone defects is a surgical challenge, and microvascular reconstruction is the current gold standard. The field of tissue bioengineering has been providing an increasing number of alternative strategies for bone reconstruction. Methods: In this preclinical study, the performance of two bioengineered scaffolds, a hydrogel made of polyethylene glycol-chitosan (HyCh) and a hybrid core-shell combination of poly (L-lactic acid)/poly ( ε -caprolactone) and HyCh (PLA-PCL-HyCh), seeded with different concentrations of human mesenchymal stromal cells (hMSCs), has been explored in non-critical size mandibular defects in a rabbit model. The bone regenerative properties of the bioengineered scaffolds were analyzed by in vivo radiological examinations and ex vivo radiological, histomorphological, and immunohistochemical analyses. Results: The relative density increase (RDI) was significantly more pronounced in defects where a scaffold was placed, particularly if seeded with hMSCs. The immunohistochemical profile showed significantly higher expression of both VEGF-A and osteopontin in defects reconstructed with scaffolds. Native microarchitectural characteristics were not demonstrated in any experimental group. Conclusion: Herein, we demonstrate that bone regeneration can be boosted by scaffold- and seeded scaffold-reconstruction, achieving, respectively, 50% and 70% restoration of presurgical bone density in 120 days, compared to 40% restoration seen in spontaneous regeneration. Although optimization of the regenerative performance is needed, these results will help to establish a baseline reference for future experiments.

The impact of surgical resection margins on outcomes for adults with head and neck osteosarcomas: A Canadian sarcoma research and Clinical Collaboration (CanSaRCC) study.

OBJECTIVE: The aim of the study is to describe the factors that influence outcome in adults with head and neck osteosarcoma (HNO) with a specific focus on the margin status. METHODS: Patients with a diagnosis of HNO between the years 1996-2021 were reviewed from the Canadian Sarcoma Research and Clinical Collaboration (CanSaRCC) Database. Baseline characteristics, pathology, treatment, and outcomes were analyzed. Univariable (UVA) and multivariable (MVA) Cox regression models were performed. 5-year locoregional control rate and overall survival (OS) were estimated using Kaplan-Meier method and Log-Rank test. RESULTS: Of 50 patients with a median age of 40 years (range 16-80), 27 (54%) were male. HNO commonly involved the mandible (n = 21, 42%) followed by maxilla (n = 15, 30%). Thirteen (33.3%) had low-intermediate grade and 26 (66.6%) had high grade tumors. Three patients (6%) had negative resection margins (>5 mm), 24 (48%) had close margins (1-5 mm), 15 (30%) had positive margins (<1mm) and 7 (16%) had unknown margin status. In total, 39 (78%) received chemotherapy - 22 (44%) received neoadjuvant chemotherapy while 17 (34%) received adjuvant chemotherapy. A total of 12 (24%) patients received radiotherapy, of whom 8 (16%) had adjuvant and 3 (6%) had neo-adjuvant. Median follow-up time was 6.3 years (range 0.26-24.9). Disease recurred in 21 patients (42%), of whom 15 (30%) had local recurrence only, 4 (8%) had distant metastasis, and 2 (4%) had both local and distant recurrence. 5-year locoregional control rate and OS was 62% and 79.2% respectively. Resection margins <3 mm was associated with lower 5 years OS and locoregional control rate (Log-Rank p = 0.02, p = 0.01 respectively). CONCLUSION: Osteosarcomas of the head and neck are rare and local recurrence remains a concern. Surgical resection with negative resection margins may improve survival, and a 3 mm resection margin threshold may optimize survival. Radiotherapy and/or chemotherapy should be considered in a multidisciplinary setting based on risk-features.

Scapular tip-thoracodorsal artery perforator free flap for total/subtotal glossectomy defects: Case series and conformance study.

BACKGROUND: Reconstruction of the tongue and floor of mouth after total/subtotal glossectomy poses a major challenge for reconstructive surgeons. Speech and deglutition after total glossectomy are usually significantly impaired, affecting the quality of life of these patients. Maintaining an adequate volume of the reconstruction is paramount to optimize speech and swallowing function postoperatively. AIM: To report a novel free flap reconstructive technique based on the subscapular system. METHODS: A preliminary cases series of patients undergoing reconstruction with scapular tip-thoracodorsal artery perforator (STTDAP) flap after total/subtotal glossectomy is reported. Conformance of the scapular tip with respect to the inner aspect of the mandible is measured in a sample of 10 subjects (20 sides) with normal scapular and mandibular anatomy, considering both the entirety of the scapular tip (overall conformance) and its caudal border (border conformance). Association between scapular morphology and conformance to the mandible was assessed statistically. RESULTS: Three patients matched inclusion criteria. Mean follow-up was 7 months. Speech and deglutition result was satisfactory in 2 patients and poor in 1 patient. Overall and border conformance were high (root mean square: 2.23 mm and 3.14 mm, respectively). Shape and angular aperture of the scapular tip significantly affected overall and border conformance, respectively. CONCLUSION: Reconstruction of the tongue with STTDAP flap after total glossectomy is feasible. Conformance between the scapular tip and mandible is optimal and, although based on preliminary evidence, patients might benefit from this technique in terms of functional outcomes.

Shouldering the load of mandible reconstruction: 81 cases of oromandibular reconstruction with the scapular tip free flap.

BACKGROUND: The scapular tip free flap (STFF) is becoming more popular for oromandibular reconstruction. This article reviewed the early and late outcomes in a larger series over 9 years. METHODS: We conducted a retrospective review of all consecutive patients who underwent oromandibular reconstruction using the STFF at London Health Sciences Centre. Demographic information, surgical data, and complications were collected and analyzed. RESULTS: From April 2008 to March 2017, 81 STFFs were performed in 80 patients. The average bony reconstruction measured 5.4 cm. Bone-only flaps were utilized in 24 cases (29.6%). Five cases (6.2%) required a single osteotomy. There were 3 (3.7%) flap failures. There were 7 plate extrusions and 11 cases of radiographic nonunion. CONCLUSION: The STFF is a reliable option with acceptable early and long-term results. The STFF may be considered as a first line option especially for shorter bone defects or in conjunction with complex soft tissue requirements.

Management Issues in the Treatment of an Ameloblastoma with an Atypical Presentation.

Benign ameloblastoma (BA) is the most common tumor arising from the odontogenic epithelium. Surgical resection with adequate margins is the mainstay of treatment due to the high index of tumor recurrence when not completely excised. Although locoregional spread has been described in the literature, it is very uncommon. We describe the treatment and follow-up of a 22-year-old woman with multiple recurrences and locoregional spread of a mandibular ameloblastoma who was referred to our center after several tumor resections with subsequent reconstructions. After a complete macroscopical removal of a new recurrence, the mandible was primarily reconstructed. A local homolateral recurrence and a second lesion in the contralateral maxilla were detected after 1-year follow-up and accordingly treated. After 4 years the patient showed a new tumor in the temporal fossa and was reoperated. The histopathology was consistent with a BA in all cases. Even though it is rare, locoregional spread of BA has been reported previously. Recurrences discovered during follow-up may require further resections. A close follow-up is mandatory, and treatment of these cases may result demanding requiring a multiple team approach, including oncologists and radiotherapists.