Rim Mandibulectomy Research Articles

Does Combined Access Mandibulotomy, Rim Mandibulectomy and Neck Dissection Compound the Late Effects of Radiotherapy?

Does Combined Access Mandibulotomy, Rim Mandibulectomy and Neck Dissection Compound the Late Effects of Radiotherapy?

Reconstruction using a submental island flap combined with mylohyoid muscle as a reliable surgical strategy after rim mandibulectomy for the management of stage 3 medication-related osteonecrosis of the mandible

The purpose of this study was to evaluate the clinical outcomes of patients with stage 3 mandibular medication-related osteonecrosis of the jaw (MRONJ) treated using a submental island flap in combination with mylohyoid muscle reconstruction after rim mandibulectomy. The medical records of 12 patients treated between January 2019 and April 2022 were analysed retrospectively. Primary wound healing was assessed as the maintenance of full mucosal coverage without signs of infection at 6 months postoperatively. The follow-up period ranged from 7 to 38 months, with an average of 21.8 months. All 12 patients (100%) experienced primary wound healing, with normal mouth opening and occlusion, and without pathological mandibular fracture or facial aesthetic problems during the follow-up period. Postoperative panoramic images revealed new bone formation in the treated areas of the mandible in four patients. During the follow-up period, one patient continuing bevacizumab and zoledronate administration for the primary cancer developed MRONJ in the same area at 13 months postoperatively and finally died. Hence the total success rate was 91.7%. In summary, for patients with stage 3 mandibular MRONJ treated with rim mandibulectomy, the submental island flap combined with mylohyoid muscle is an effective reconstructive option for wound-healing and possible bone regeneration of denuded bone.

下顎辺縁切除変法による rim mandibulectomy および sagittal mandibulectomy 後の下顎再建

下顎辺縁切除変法による rim mandibulectomy および sagittal mandibulectomy 後の下顎再建

Use of Recombinant Human Bone Morphogenetic Protein 2 for Mandible Reconstruction

Microvascular osseous free tissue transfer is the standard of care for reconstructing significant mandibulectomy defects; however, this procedure can carry a significant rate of morbidity. To describe the use of recombinant human bone morphogenetic protein 2 (rhBMP-2) as an option for segmental or near-complete rim mandibulectomy defects in a select group of patients, precluding the need for free tissue transfer. A retrospective review was performed of 6 patients who had undergone repair of a mandible defect using rhBMP-2 with beta-tricalcium phosphate matrix or a cadaveric bone graft at a single tertiary care institution. The defects resulted from resection of benign neoplasms or from previous trauma. Reconstruction success was defined as no hardware problems, healing without infection, no need for further surgical procedures, and imaging evidence of healing and union without resorption. The median follow-up period was 37.5 months (range, 12-51 months). Five of 6 patients underwent successful restoration of the mandibulectomy defect. One patient with a compromised immune system developed a significant postoperative wound infection requiring further reconstructive surgery. The use of an rhBMP-2-based reconstructive approach is a feasible option for segmental or near-complete rim mandibulectomy defects in a select group of patients. 4.

Mandibular Rim Excision in Seven Dogs

To describe a surgical technique for excision of minimally invasive mandibular tumors at the level of the premolar and molar teeth, and report outcome in 7 dogs that had mandibular rim excision. Case series. Dogs (n=7) with a mandibular tumor at the level of the premolar and molar teeth. Using an intraoral approach to the mandible, buccal, and lingual mucosal incisions are made to obtain a 10 mm clean margin beyond neoplastic tissue. After subperiosteal soft tissue elevation, a curvilinear rim mandibulectomy is performed, leaving the mandibular canal and ventral cortex intact, followed by osteoplasty. The remaining attached gingiva and alveolar mucosa are sutured over the bony defect. Seven dogs were treated (1997-2008) for odontogenic and early malignant neoplasms involving the mandible by mandibular rim excision. All dogs had healed, healthy gingival covering over the surgical defect, very good postoperative function, and good quality of life. Mandibular rim excision, with preservation of the ventral cortex and mandibular canal content, can be a good option for treatment of early odontogenic and malignant lesions of the mandible in medium to large breed dogs. In medium to large dogs with minimally invasive mandibular neoplasia, mandibular rim excision should be considered as a viable surgical option.

The effect of rim mandibulectomy configuration and residual segment size on postoperative fracture risk: An in vitro study

Purpose: This study evaluated the effect that size and shape of rim mandibulectomy has on residual mandibular strength and resistance to fracture, with the ultimate goal of improving the use of this technique and establishing a threshold for the application of prophylactic internal fixation. Materials and Methods: Ten partially dentate dry human mandibles were mounted in a manner replicating the pterygomasseteric musculature. Unilateral midbody serial rim excisions of increasing size were completed in both a curvilinear and right-angled fashion, and physiologic forces were gradually applied to a level of residual segment fracture. Dimensional measurements were taken of the specimens before and after fracture to understand which factors contributed to failure. Results: On average, a curvilinear excision configuration resisted higher occlusal forces with a smaller residual segment than did the right-angled excision configuration. A residual inferior border thickness of less than 9 mm could not predictably withstand force application within the limits of the experimental model. Conclusion: These data support the use of a curvilinear excision configuration for rim mandibulectomies. Reproducibility of the location of the residual segment failure and other consistent residual segment dimensional information have implications regarding the limitations of this technique, beyond which the use of adjunctive support in the form of maxillomandibular fixation or prophylactic internal fixation may be indicated. © 2001 American Association of Oral and Maxillofacial Surgeons

Discussion

In this study, Melugin et al have attempted to evaluate the effect of the size and shape of a rim mandibulectomy on residual mandibular strength and resistance to fracture. Their goal was to improve the use of the rim mandibulectomy technique, as well as to establish a threshold for the application of prophylactic internal fixation. In reviewing their study, it is clear that they have further enhanced our understanding of this procedure. I believe that they have provided further data that the curvilinear shape of the osteotomy is biomechanically more favorable than the right-angled osteotomy and is less likely to fracture when used in similar surgical settings. They also suggest in their analysis that fracture formation was relatively uniform, arising at the posterior aspect of the osteotomy, and that this should be taken into consideration when a surgeon is considering the application of prophylactic internal fixation. I believe that this is an important piece of data that has clinical significance. However, although I believe the study provides a suggestion as to when prophylactic internal fixation should be used, it does not answer this question completely.

Mandibular invasion in oral cancers.

Mandibular resection for oral cancers has significant aesthetic and functional sequelae. A reliable preoperative predictor of mandibular invasion is required to guide the need for and extent of mandibular resection. An orthopantomogram of the mandible is an accurate, reliable, cost-effective predictor of bony involvement except for central arch lesions. The feasibility of outer table rim mandibulectomy alone in patients with floor of mouth tumors needs to be examined carefully.

The dentate adult human mandible: an anatomic basis for surgical decision making.

Mandibular resection for oral cancer assumes two major forms; segmental mandibulectomy for invasion and rim mandibulectomy for margins, the extent of removal being governed by the need to ensure oncologic safety. The purpose of our study was to establish basic principles for optimal resection design in various clinical situations. Thirty-six cadaveric, adult, dentate human mandibles were examined in detail and sectioned at six points each to study the cross- sectional anatomy at these sites. The majority of bones (32 of 36) revealed a conspicuous medullary core with a thin cortical rim 2 to 4 mm in thickness. The inferior alveolar nerve was found to course consistently within the anterior segment of the ramus and to dip significantly within the body (median height at molar area 7 mm). Accordingly, rim resections cannot include the entire medullary core and nerve as currently defined, whereas segmental resections can spare the posterior segment of the ramus in appropriate cases.

Tomographic Studies of Human Jaws to Assess Potentials for Preserving the Blood Supply in Rim Mandibulectomies

Rim mandibulectomy, resecting the aveolar segment of the mandible while preserving the inferior cortical arch, has been shown to be a biologically and surgically sound procedure. In order to study the surgical anatomy of the mandible and determine the reproducibility of the anatomic markers and neurovascular supply, we studied serial tomographic cuts of 50 living human mandibles (21 males, 29 females; ages 17 to 87). The dentition was complete in 13, partial in 30, and edentulous in 7. The review showed that the location of anatomic structures was symmetrical in all these adult patients regardless of age, sex, or extent of dentition. (The only significant difference was in the height of the alveolus, which was decreased in edentulous patients.) The data show that in performing a rim mandibulectomy, the blood supply may be preserved in most patients if at least 11 mm of vertical height is preserved of the inferior cortex of the body of the mandible.

Management of the mandible in oral cancer.

Modern head and neck surgery has focused on patient rehabilitation and restoration of form and function in the treatment of oral cancers. An important aspect of that process has been the conservation of the mandible in tumor ablation and the reconstruction of the mandible if segmental resection is indicated. This article outlines the science and clinical data behind rim mandibulectomy and the mandibular osteotomy and "swing" to gain access to tumors of the posterior tongues and pharynx. Additionally, the various methods of reconstruction of the mandible in use today as well as the advantages and disadvantages of each are addressed.

Mandible preservation with oral cavity carcinoma: Rim mandibulectomy versus sagittal mandibulectomy

Rim mandibulectomy, a mandibular-preserving procedure, has proven to be a successful method of treating squamous cell carcinoma with limited mandibular involvement. The operation involves resection of the occlusal rim of the mandible. Using strain gauge techniques, we investigated how much bone should remain at the rim mandibulectomy site. Maintenance of a 1-cm-thick segment of bone inferiorly is required to reduce the risk of fracture formation. In comparing the relative strength of the different mandibular preservation techniques, the rim mandibulectomy was found to be more resistant to fracturing than was lingual sagittal mandibulectomy.

Rim mandibulectomy for cancer of the oral cavity

Improvements in our understanding of the methods of mandibular invasion by malignancies and refinements in the biomechanical analysis of mandibular osteotomies led us to modify our standard operative procedure for this disease process. Over a 10 year period, we performed rim mandibulectomy to treat oral cavity malignancies with mandibular involvement. This retrospective analysis of 38 patients comparing rim mandibulectomy with the traditional segmental mandibulectomy has demonstrated equivalent local control rates between rim mandibulectomy and segmental resection (75 and 64 percent, respectively). Patients with rim mandibulectomies were more satisfied with their postoperative appearance, and some were able to wear lower dentures if well motivated. In performing the rim mandibulectomy, we found that smooth, curved osteotomies without step-offs resulted in a technically simple operation that was biomechanically sound and had a low complication rate. Rim mandibulectomy, because it is based on sound pathologic principles and does not disrupt the mandibular arch, is an operation that adequately resects the tumor without compromising the cancer operation or the patient.

Total glossectomy

Total glossectomy is a procedure based on sound oncologic principles, and its usefulness may not be fully appreciated. Given the dimensions of the tongue and the need to obtain a wide margin of resection, this procedure may be indicated in selected T 3 lesions and recurrences after irradiation. The procedure offers excellent palliation of pain, and form and function may be preserved by rim mandibulectomy when indicated. New reconstructive techniques allow for speedier recovery. Aspiration need not be a complication of total glossectomy if care is taken to preserve the superior laryngeal nerve. Speech rehabilitation plays an important role in returning these patients to their normal environment. Overall 1 and 3 year disease-free survival rates have been encouraging.