Clinical outcomes following intraoperative pedicle disruption in fibula free flaps.

OBJECTIVES: Iatrogenic injury of the fibula free flap pedicle is rare. Postoperative flap survival and reconstructive outcomes following intraoperative pedicle severance are unknown. This study assesses free flap outcomes following accidental severance of the peroneal vessels. METHODS: Multi-institutional retrospective chart review from 2000 to 2020. RESULTS: Of 2975 harvested fibula free flaps, 26 had a history of pedicle severance during surgical reconstruction. Reasons for intraoperative pedicle severance included transection during muscular dissection 10/26 (39%), accidental severance with the bone saw 12/26 (46%), and other 4/26 (15.6%). The surgeon responsible for pedicle severance included residents 5/26 (19%), fellows 10/26 (39%), attendings 10/26 (39%), and unknown 1/26 (3.9%). The pedicle artery and vein were severed 10/26 (39%), artery 8/26 (31%), and vein 8/26 (31%). Truncated pedicle vessels were used 3/26 (11.7%), intraoperative anastomoses were performed 23/26 (89%). Postoperative revision in the OR within 7 days of surgery was required 6/26 (23%); 4 flaps were salvaged and 2 flaps failed, both arterial thrombosis. Flap failure was attributed to vascular thrombosis. Long-term flap survival and successful reconstructions were reported 24/26 (92%). CONCLUSION: Accidental severance of fibula free flap pedicle vessels can be corrected with intraoperative repair, without affecting long-term flap survival or reconstructive outcomes. Protecting the flap vessels while using the bone saw and during intramuscular dissection prevents accidental severance.

Extent of Extranodal Extension in Oral Cavity Squamous Cell Carcinoma is Not Independently Associated With Overall or Disease-Free Survival at a 2.0-mm Threshold.

PURPOSE: The presence of extranodal extension (ENE) conveys a poor prognosis in oral cavity squamous cell carcinoma (OSCC); however, there is no consensus regarding whether the histopathologic extent of ENE (e-ENE) may be a more discriminating prognostic indicator. The purpose of this study was to assess the impact of minor ENE (<2.0 mm) versus major ENE (≥ 2.0 mm) on overall survival (OS) and disease-free survival (DFS) in OSCC. MATERIALS AND METHODS: A single-institution, retrospective cohort study was designed using an electronic medical record review. Inclusion criteria included patients with OSCC and cervical node metastasis. All subjects were treated between the years 2009 and 2017 in the Michigan Medicine Department of Oral and Maxillofacial Surgery (Ann Arbor, Michigan). The primary predictor variable was e-ENE, measured as the maximum distance of tumor invasion into extranodal tissue from the outer aspect of the nodal capsule. Primary outcome variables were OS and DFS. Other covariates included demographic data, tumor staging, and histopathologic data. Descriptive statistics were performed. Kaplan-Meier survival plots for OS and DFS were performed. The data were mined for an alternative threshold at which e-ENE may impact survival using Cox proportional hazards models. RESULTS: One hundred sixty eight subjects were included (91 ENE-negative, 48 minor ENE, and 29 major ENE). Most subjects were male (62%) and the mean age was 62.9 years. Mean follow-up time was 2.97 +/- 2.76 years. There was no statistically significant difference in OS or DFS between minor and major ENE. Five-year OS for minor ENE was 30.4% versus 20.7% for major ENE (P = .28). Five-year DFS for minor ENE was 26.7% versus 18.1% for major ENE (P = .30). Five-year OS and DFS was worse for subjects with ENE-positive disease versus ENE-negative disease (OS: 26.9% vs 63.1%, hazard ratio [HR]: 2.70, 95% confidence interval [CI]: [1.77, 4.10], P < .001; DFS: 23.7% vs 59.7%, HR = 2.55, 95% CI [1.71, 3.79], P < .001). At an alternative threshold of 0.9 mm e-ENE, there was greater DFS in subjects with e-ENE 0.1-0.9 mm versus e-ENE > 0.9 (40.6% vs 18.9%, respectively) (HR = 0.49, 95% CI [0.24, 0.99], P = .047). CONCLUSION: There was no independent association between survival and e-ENE at a 2.0-mm threshold.

Validation of Tabletop Microscopes for Microsurgery Simulation and Training.

PURPOSE: Oral and maxillofacial surgery residency programs are increasingly adopting microsurgery as a core element of training; however, many barriers exist that limit trainees' proficiency. The purpose of this study was to perform a validation of 2 tabletop microscope simulations for their use as a training tool, which could serve as an affordable, alternative method to traditional microsurgery training methods. METHODS: A prospective, single-institution, multidepartmental validation study was performed. Two microscopes (monocular digital [DM] and binocular stereo [SM]) were used to perform anastomoses on simulation vessels including a silastic tube and a chicken thigh femoral artery. A microsurgeon panel was selected from a population of microsurgery faculty and fellows at Michigan Medicine (Ann Arbor, MI) to perform the anastomoses. The surgeons each performed 4 anastomoses, using each microscope with each vessel, and subsequently completed a survey evaluating the simulation. Predictor variables were the microscope and the vessel. Primary outcome variable was readiness for use, which was defined as the simulation's ability to incorporate into a microsurgical training curriculum in its current state. Secondary outcome variables included realism, value, usefulness, relevance, difficulty, and cost. Paired t tests were used to compare responses. Alpha was set to 0.05. RESULTS: Seven microsurgeons performed the simulation from the departments of oral and maxillofacial surgery (n = 5), plastic and reconstructive surgery (n = 1), and otolaryngology (n = 1). For readiness, the SM simulation required either no modification (n = 4) prior to implementation into a microsurgery curriculum or minimal modification (n = 3), compared to the DM simulation which required significant modification (n = 4) or extensive modification and re-evaluation (n = 3) (P = .002). The SM demonstrated a greater mean realism score than the DM for depth perception (5.00 vs 1.57, P < .001), field of view (4.57 vs 3.57, P = .038), lighting (5.00 vs 4.00, P = .038), and clarity (5.00 vs 3.86, P = .030). There was no statistically significant difference between SM and DM in value, usefulness, relevance, difficulty, or cost. CONCLUSIONS: Tabletop microscopes demonstrate considerable promise in the future of microsurgical education. The SM simulation was a realistic simulation that may be ready for use in a microsurgical curriculum. Future studies are required to demonstrate the efficacy of this simulation on microsurgical trainees.

Virtual Externship Programs Can Serve as a Viable Alternative to In-Person Externship Experiences in Oral and Maxillofacial Surgery.

PURPOSE: The purpose of this study is to describe a model for a virtual externship program in oral-maxillofacial surgery (OMS); to quantify the value of a virtual externship in increasing understanding of the program structure, scope, and commitment to diversity; and to offer qualitative feedback on structural components. METHODS: A retrospective study was completed comparing dental student perceptions of an OMS program and the virtual externship experience prior to and following an OMS residency virtual externship event. An electronic survey was distributed to registrants and included 25 questions: 5 related to demographics, 17 ascertaining understanding of various components of the residency and perception of virtual externships, and 3 text-based response queries. RESULTS: Of the 167 attendees, 125 individuals completed the pre-externship survey and 50 completed the postexternship survey for a response rate of 74.8 and 29.9% respectively. Respondents of both surveys included 30 men and 20 women, aged 18 to 34, at various stages of dental school training and of various ethnic backgrounds. All externs reported an interest in participating in virtual externships if offered by OMS programs. Understanding of scope of practice, daily activities of the program and residents, living in Ann Arbor, relationship between residents and with faculty, and program structure demonstrated a significant increase (P < .001). Perceived commitment to diversity and respect for people of different races, cultures, and backgrounds also showed a significant increase following the event (P < .001). CONCLUSIONS: A virtual externship can successfully duplicate many of the most valuable components of an in-person externship to allow enhanced understanding and interest in the residency program and can incorporate novel components otherwise not possible in an-person externship.

Work-Life Balance for Oral and Maxillofacial Surgeons.

Oral and maxillofacial surgeons experience high levels of stress and work-home conflict, which predispose them to burnout. There is emerging evidence in support of work-life integration to prevent burnout; interventional strategies exist on an individual and organizational level. This article explores the current evidence on promoting work-life integration for improved surgeon satisfaction, performance, and efficiency. Work-life integration initiatives can help promote the recruitment and retention of a diverse surgical workforce in oral and maxillofacial surgery.

The Diversity Bonus in Oral and Maxillofacial Surgery.

The diversity bonus theorem developed by Scott Page postulates that in specific environments, diversity is an absolute necessity to creating the most successful team. The theorem dispels the myth that institutions must choose between diversity and excellence. Within oral and maxillofacial surgery, this bonus is captured through expanded access to care, more equitable and relevant research, and attracting the best and brightest to the specialty. To capture the bonus, oral and maxillofacial surgery must invest in policy changes to admissions and hiring practices, and offer training in communication, cultural competency, and implicit bias.

An In-House Computer-Aided Design and Computer-Aided Manufacturing Workflow for Maxillofacial Free Flap Reconstruction is Associated With a Low Cost and High Accuracy.

PURPOSE: In-house computer-aided surgical design and computer-aided manufacturing (CAD/CAM) can be used in oral and maxillofacial surgery for virtual surgical planning and 3-dimensional printing of patient-specific models. The purpose of this study was to measure the cost and accuracy of an in-house CAD/CAM workflow for maxillofacial free flap reconstruction. MATERIALS AND METHODS: A retrospective cohort study of patients undergoing mandibular resection and free flap reconstruction was performed between July 2017 and March 2018 in which in-house CAD/CAM was used. The predictor variable was the in-house CAD/CAM workflow. The outcome variables were in-house workflow cost, as measured by the material expenses, and accuracy, as measured by comparative distance, osteotomy angle, and surfaced overlay measurements and the root mean square (RMS) between the preoperative virtual reconstructive plan and the postoperative computed tomography scan. Additional variables evaluated were time required for in-house CAD/CAM workflow, and clinical and radiographic outcomes. RESULTS: In-house CAD/CAM was used for 26 patients undergoing mandibular resection for benign or malignant disease and free flap reconstruction with fibula (n = 24) or scapula free flap (n = 2). Overall flap success rate was 95%. The mean in-house workflow cost per case was $3.87 USD. There were no significant differences between the mean comparative distance and osteotomy angle measurements between the planned and actual mandibular reconstructions with an RMS ranging from 5.11 to 9.00 mm for distance measurements and 17.41° for the osteotomy angle measurements. The mean surface overlay difference was 1.90 mm with an RMS of 3.72 mm. CONCLUSIONS: The in-house CAD/CAM workflow is a low cost and accurate option for maxillofacial free flap reconstruction. The in-house workflow should be considered as an alternative to current practices using proprietary systems in select cases.

Is Perineural Invasion a Reasonable Indicator for Neck Dissection in cT1N0M0 Squamous Cell Carcinoma of the Oral Cavity?

PURPOSE: Perineural invasion (PNI) is considered an adverse histological feature in oral squamous cell carcinoma (OSCC). Controversy exists regarding elective neck dissection (END) in cT1N0M0 OSCC with PNI as the only risk factor. The purpose of this study was to evaluate PNI as an indicator for END, as well as its utility when combined with the depth of invasion (DOI) as a second indicator. PATIENTS AND METHODS: cT1N0M0 (AJCC8) OSCC patients treated from August 1998 to July 2017 in the Department of Oral and Maxillofacial Surgery, University of Michigan (MI), and Beijing Stomatological Hospital, Capital Medical University (BSH) were reviewed. Data from these sites included both prospectively captured data housed in a database and retrospective data. RESULTS: 283 cT1N0M0 OSCC patients were analyzed. The tongue was the most common subsite (56.2%). Ninety-nine (99) patients received END and 184 neck observation. PNI was found in only 8 patients (2.83%) all in the tongue or inferior gingiva. END was performed in 7 of the PNI patients. The mean depth of invasion for tumors with PNI was 3.97 mm, compared to 2.54 mm in tumors without PNI. PNI was statistically correlated with nodal disease (pN+) and extranodal extension (ENE+). After using DOI as a primary indicator for END, no additional PNI patients benefited from END. In addition, only 2 patients had PNI identified preoperatively both with 5 mm DOI, and therefore, already indicated for END on the basis of DOI status. CONCLUSIONS: PNI status is statistically correlated with pN+ and ENE + pathology in cT1N0M0 OSCC. After using DOI as a primary indicator for END, PNI status had no added value in decision making. Even surgeons who do not use DOI will find very limited value in PNI status with less than 1% preoperative prevalence (0.71%) in this patient population.

Comparison of Early Oral Cancer Depth of Invasion From the American Joint Committe on Cancer 7th to 8th Edition Criteria. Does the Difference Impact the Accuracy of Clinical Decision Making?

PURPOSE: Depth of invasion (DOI) is an independent predictor of regional metastasis in oral squamous cell carcinoma. Measurement criteria for DOI were modified in the American Joint Committee on Cancer (AJCC) eighth edition. The purpose of this study was to compare DOI AJCC seventh (DOI7) and eighth (DOI8) edition criteria on frozen section accuracy for decisions regarding elective neck dissection (END) in cT1N0 oral squamous cell carcinoma. PATIENTS AND METHODS: A blinded, retrospective, comparative study of patients who underwent ablative surgery at the University of Michigan was completed. The predictor variable was criteria for DOI measurement. The outcome variables were concordance between DOI7 and DOI8 measurements and accuracy using thresholds for END. Effect of tumor growth pattern and worst pattern of invasion, and the difference between DOI8 on frozen and permanent specimen were assessed. RESULTS: A total of 30 specimens of T1N0 oral squamous cell carcinoma (16 tongue, 5 alveolus, 5 floor of mouth, 4 buccal mucosa) were included. DOI7 versus DOI8 on frozen and permanent specimen were significantly different (P < .05) but clinically insignificant and highly correlated (r > 0.99, P < .001). One hundred percent concordance between DOI7 and DOI8 was noted on frozen specimen in predicting the need for END when compared with permanent pathology DOI. There was no significant impact of tumor growth pattern or worst pattern of invasion on measurements and no significant difference in DOI on frozen and permanent specimen for DOI8 (P = .68). Excellent agreement between pathologists for all measurements was observed (ICC>0.99, P < 0001). CONCLUSIONS: High concordance between DOI measurements by AJCC seventh and eighth edition criteria suggests that guidelines for DOI thresholds for END in patients with T1N0 tumors developed using the AJCC seventh edition can be safely applied using AJCC eighth edition criteria. DOI measurement by AJCC 8 criteria on frozen specimen can be used to guide decision-making regarding END, given the high correlation to AJCC 8 permanent DOI measurement.

Effect of α2­macroglobulin in the early stage of jaw osteoradionecrosis.

Advanced osteoradionecrosis (ORN) is one of the most serious complications in patients with head and neck cancer, resulting in poor prognosis. Numerous studies have therefore focused on the pathogenesis and interventions of ORN early stage. The present study aimed to investigate whether α2­macroglobulin (α2M) could prevent early­stage jaw osteoradionecrosis caused by radiotherapy (RT). Following local injection of α2M, a single dose of 30 Gy was delivered to rats for pathological exploration. For 28 days, the irradiated mandible and soft tissues were examined for potential changes. Furthermore, primary human bone marrow mesenchymal stem cells pretreated with α2M followed by 8 Gy irradiation (IR) were also used. Tartrate­resistant acid phosphatase assay, terminal uridine deoxynucleotidyl nick end labeling assay and immunohistochemical staining were performed on irradiated mandibular bone, tongue or buccal mucosa tissues from rats. Cell proliferation was assessed by evaluating the cell morphology by microscopy and by using the cell counting kit­8. Fluorescence staining, flow cytometry and western blotting were conducted to detect the reactive oxygen species level, cell apoptosis and protein expression of superoxide dismutase 2 (SOD2), heme oxygenase­1 (HO­1) and phosphorylated Akt following irradiation. The results demonstrated that α2M attenuated physical inflammation, osteoclasts number and fat vacuole accumulation in mandibular bone marrow and bone marrow cell apoptosis following IR in vivo. Furthermore, α2M pretreatment suppressed the expression of 8­hydroxy­2'­deoxyguanosine in mandibular bone and tongue paraffin embedded sections, which is a marker of oxidative damage, and increased SOD2 expression in mucosa and tongue paraffin embedded sections. The present study demonstrated the efficient regulation of antioxidative enzymes, including SOD2 and heme oxygenase­1, and reduction in oxidative damage by α2M. In addition, in vitro results confirmed that α2M may protect cells from apoptosis and suppress reactive oxygen species accumulation. Overall, the present study demonstrated that α2M treatment may exert some radioprotective effects in early­stage ORN via antioxidant mechanisms, and may therefore be considered as a potential alternative molecule in clinical prophylactic treatments.

Oral Lichen Planus-Associated Oral Cavity Squamous Cell Carcinoma Is Associated With Improved Survival and Increased Risk of Recurrence.

PURPOSE: We investigated the overall survival (OS), disease-specific survival (DSS), and disease-free survival among patients with oral lichen planus-associated oral cavity squamous cell carcinoma (OLP-OCSCC). The secondary objective was to assess the annual risk of tumor recurrence or second primary tumor (SPT). MATERIALS AND METHODS: A comparative retrospective study was performed of patients with OLP-OCSCC presenting between June 2007 and December 2018 to the Department of Oral and Maxillofacial Surgery, Michigan Medicine (Ann Arbor, MI) and patients with OCSCC in the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database (1973 to 2015). RESULTS: A total of 87 patients with OLP-OCSCC met the inclusion criteria, and 55,165 patients with OCSCC from the SEER database were included. The proportion of women was greater in the OLP group than in the SEER group (56.3 vs 38.0%; P < .001). In the OLP group, 47.1% had no smoking history and 43.7% had no alcohol history. Most patients in the OLP group had presented with stage I disease (46.0%) compared with 31.7% in the SEER group (P = .004). Overall, the OS and DSS were significantly greater in the OLP group than in the SEER group at all points from 1 to 5 years (P ≤ .01). In the OLP group, 46 patients (52.9%) had at least 1 recurrence or SPT. At 10 years, the predicted mean number of recurrences was 1.93 per patient (95% confidence interval, 1.56 to 2.39). CONCLUSIONS: OLP-OCSCC frequently affects women, nonsmokers, and nondrinkers and presents with localized disease at a high frequency. Patients with OLP-OCSCC have increased OS and DSS and a greater risk of tumor recurrence or SPT compared with OCSCC in the general population. Lifelong, frequent surveillance is recommended for patients with OLP-OCSCC owing to the risk of late recurrence. Future studies are needed to understand the pathophysiology of OLP-OCSCC.

Intraoperative Depth of Invasion Is Accurate in Early-Stage Oral Cavity Squamous Cell Carcinoma.

PURPOSE: Depth of invasion (DOI) is one predictor of nodal metastasis in oral cavity squamous cell carcinoma (OCSCC) and can facilitate the decision to complete an elective neck dissection (END) in early-stage disease with a clinically negative neck. The purpose of this study was to investigate the accuracy of DOI in intraoperative frozen specimens for T1N0 oral OCSCC. MATERIALS AND METHODS: To compare the accuracy of DOI in frozen versus permanent specimens, we completed a prospective, blinded study of 30 patients with cT1N0 OCSCC who presented between October 2016 and December 2017. RESULTS: DOI in frozen specimens was 96.8% accurate in predicting the need for END with a sensitivity of 90.9%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 95.2%. A strong correlation was found between DOIs in frozen and permanent specimens measured by head and neck (HN) pathologists (r = 0.96; 95% confidence interval [CI], 0.93 to 0.97), between HN pathologists using frozen specimens (r = 0.98; 95% CI, 0.95 to 0.99) and permanent specimens (r = 0.95; 95% CI, 0.91 to 0.98), and in DOIs in frozen specimens communicated intraoperatively versus measured by HN pathologist 1 (r = 0.93; 95% CI, 0.86 to 0.97) and HN pathologist 2 (r = 0.95; 95% CI, 0.89 to 0.98). Only 1 patient who did not undergo an END based on frozen specimens was undertreated owing to upgrading of the DOI in permanent specimens. CONCLUSIONS: DOI in intraoperative frozen sections has an accuracy of 96.8% and may be reliably used as a clinical tool to determine the need for END in early-stage OCSCC.