Faculty Bibliography

LEARNING OBJECTIVES/OBJECTIVE:After studying this article, the participant should be able to: 1. Appreciate the evolution and increasing complexity of transplanted facial allografts over the past two decades. 2. Discuss indications and contraindications for facial transplantation, and donor and recipient selection criteria and considerations. 3. Discuss logistical, immunologic, and cost considerations in facial transplantation, in addition to emerging technologies used. 4. Understand surgical approaches and anatomical and technical nuances of the procedure. 5. Describe aesthetic, functional, and psychosocial outcomes of facial transplantation reported to date. SUMMARY/CONCLUSIONS:This CME article highlights principles and evolving concepts in facial transplantation. The field has witnessed significant advances over the past two decades, with more than 40 face transplants reported to date. The procedure now occupies the highest rung on the reconstructive ladder for patients with extensive facial disfigurement who are not amenable to autologous reconstructive approaches, in pursuit of optimal functional and aesthetic outcomes. Indications, contraindications, and donor and recipient considerations for the procedure are discussed. The authors also review logistical, immunologic, and cost considerations of facial transplantation. Surgical approaches to allograft procurement and transplantation, in addition to technical and anatomical nuances of the procedure, are provided. Finally, the authors review aesthetic, functional, and psychosocial outcomes that have been reported to date.

OBJECTIVES/OBJECTIVE:To characterize the physicochemical and mechanical properties of a milled fiber-reinforced composite (FRC) for implant-supported fixed dental prostheses (FDPs). METHODS:connector area and 2.5 mm-height lingual extension). A hybrid resin composite was veneered onto the frameworks. FDPs were subjected to step-stress accelerated-life fatigue testing until fracture or suspension. Use level probability Weibull curves at 300 N were plotted and the reliability for 100,000 cycles at 300, 600 and 800 N was calculated. Fractographic analysis was performed by stereomicroscope and SEM. RESULTS:The FRC consisted of an epoxy resin (∼25%) matrix reinforced with inorganic particles and glass fibers (∼75%). Multi-layer continuous regular-geometry fibers were densely arranged in a parallel and bidirectional fashion in the resin matrix. Fatigue analysis demonstrated high probability of survival (99%) for FDPs at 300 N, irrespective of framework design. Conventional FDPs showed a progressive decrease in the reliability at 600 (84%) and 800 N (19%), whereas modified FDPs reliability significantly reduced only at 800 N (75%). The chief failure modes for FRC FDPs were cohesive fracture of the veneering composite on lower loads and adhesive fracture of the veneering composite at higher loads. SIGNIFICANCE/CONCLUSIONS:Milled epoxy resin matrix reinforced with glass fibers composite resulted in high probability of survival in the implant-supported prosthesis scenario.

Chronic facial paralysis can lead to significant functional and psychosocial impairment. Treatment often involves free muscle flap-based facial reanimation surgery. Although surgical techniques have advanced considerably over the years, consensus has yet to be reached for postoperative outcome evaluation. To facilitate outcome comparison between the various techniques for free muscle-flap-based reanimation, a standardized, widely accepted functional outcomes assessment tool must be adopted.

STUDY OBJECTIVES/OBJECTIVE:Identifying optimal treatment for infants with Robin sequence (RS) is challenging due to substantial variability in the presentation of upper airway obstruction (UAO) in this population. Objective assessments of UAO and treatments are not standardized. A systematic review of objective measures of UAO was conducted as step towards evidence based clinical decision making for RS. METHODS:A literature search was performed in Pubmed and Embase databases (1990-2020) following PRISMA-guidelines. Articles reporting on RS and UAO-treatment were included if the following objective measures were studied: oximetry, polysomnography and blood gas. Quality was appraised by methodological index for non-randomized studies (MINORS, range:0-24). RESULTS:A total of 91 articles met inclusion criteria. Mean MINORS-score was 7.1 (range:3-14). Polysomnography was most frequently used (76%) followed by oximetry (20%) and blood gas (11%). Sleep position of the infant was reported in 35% of studies, with supine position most frequently, and monitoring time in 42%, including overnight recordings in more than half. Of 71 studies that evaluated UAO-interventions, the majority used polysomnography (90%), of which 61% did not specify the polysomnography technique. Reported polysomnography metrics included oxygen saturation (61%), apnea-hypopnea index (52%), carbon dioxide levels (31%), obstructive-apnea-hypopnea index (27%), and oxygen-desaturation-index (16%). Only 42 studies reported indications for UAO-intervention, with oximetry and polysomnography thresholds used equally (both 40%). In total, 34 distinct indications for treatment were identified. CONCLUSIONS:This systematic review demonstrates a lack of standardization, interpretation and reporting of assessment and treatment indications for UAO in RS. An international, multidisciplinary consensus protocol is needed to guide clinicians on optimal UAO assessment in RS.

OBJECTIVE:The effectiveness of GBR procedures for the reconstruction of periodontal defects has been well documented. The objective of this investigation was to evaluate the degradation kinetics and biocompatibility of two resorbable collagen membranes in conjunction with a bovine xenograft material. MATERIALS AND METHODS/METHODS:Lower premolars and first molars were extracted from 18 male Yucatan minipigs. After 4 months of healing, standardized semi-saddle defects were created (12 mm × 8 mm × 8 mm [l˙̇ × W˙ × d]), with 10 mm between adjacent defects. The defects were filled with a bovine xenograft and covered with a either the bilayer collagen membrane (control) or the porcine pericardium-derived collagen membrane (test). Histological analysis was performed after 4, 8, and 12 weeks of healing and the amount of residual membrane evaluated. Non-inferiority was calculated using the Brunner-Langer mixed regression model. RESULTS:Histological analysis indicated the presence of residual membrane in both groups at all time points, with significant degradation noted in both groups at 12 weeks compared to 4 weeks (p = .017). No significant difference in ranked residual membrane scores between the control and test membranes was detected at any time point. CONCLUSIONS:The pericardium-derived membrane was shown to be statistically non-inferior to the control membrane with respect to resorption kinetics and barrier function when utilized for guided bone regeneration in semi-saddle defects in minipigs. Further evaluation is necessary in the clinical setting.

BACKGROUND:Hematoma after non-oncologic breast surgery is a common concern requiring expeditious treatment. The purpose of this study is to perform an evidence-based review of perioperative factors that may contribute to hematoma in non-oncologic breast procedures. METHODS:A comprehensive literature review was performed of non-oncologic breast procedures: breast augmentation, single-stage augmentation-mastopexy, mastopexy, and reduction. In total, 28 studies highlighting incidence and potential risk factors for hematoma were included; overall level of evidence was established regarding each perioperative factor examined and hematoma rate. RESULTS:The hematoma rate in breast augmentation ranges from 0.2 to 5.7%. There is inconclusive evidence to support an association between pocket choice or incision location and hematoma rate (Level III) and no evidence of an association between implant type and hematoma (Level V). Single-stage augmentation-mastopexy may have a lower hematoma rate than augmentation alone (Level II). Hematoma may increase the risk of capsular contracture (Level III). In breast reduction, the hematoma rate ranges from 1.0 to 9.3%. Evidence of an association between incision choice and hematoma rate is inconclusive (Level III). Use of epinephrine-containing solution, pedicle choice, and resection weight do not appear to affect hematoma rate (Level V, II, and II, respectively). The use of postoperative drains and ketorolac do not affect the incidence of hematoma (Level I and III, respectively). Intraoperative hypotension may increase the risk of hematoma after breast reduction (Level III). CONCLUSIONS:Breast hematomas are not uncommon complications. Current literature lacks ample evidence for risk factors for hematoma after non-oncologic breast procedures, warranting further, high-powered investigations. LEVEL OF EVIDENCE III/UNASSIGNED:This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

BACKGROUND:Numerous studies have evaluated the effect of post-mastectomy radiotherapy (PMRT) on autologous breast reconstruction, but the variability of PMRT regimens and inadequate controls have made results difficult to interpret. Therefore, in this study, irradiated free-flaps are compared to non-irradiated internal controls in patients who underwent immediate bilateral reconstruction followed by unilateral PMRT to better delineate the effect of PMRT. The role of regional nodal irradiation (RNI) is also specifically assessed. METHODS:Appropriate patients were identified through retrospective review. Complications such as fat necrosis, fibrosis, infection, delayed healing, and flap loss, as well as revision surgeries, among the irradiated free-flaps were compared to those on the contralateral non-irradiated side. Additional analyses were performed to evaluate the effect of patient demographics and treatment characteristics, such as RNI, on complications involving the irradiated free-flaps. RESULTS:Seventy-three women were included. There was no significant difference between complication rates for the irradiated and non-irradiated free-flaps (39.7% vs. 38.4%, p = .78), although irradiated free-flaps were more likely to have fibrosis (17.0% vs. 0.0%; p < .0001) and multiple complications (9.6% vs. 0.0%; p = .02). Both groups underwent a similar number of revision surgeries (42.5% vs. 41.1%; p = .29). Looking at the irradiated free-flaps, internal mammary node (IMN) irradiation was the only factor predictive of complications (IRR 3.80, CI 1.32-10.97; p = .01). CONCLUSIONS:PMRT may contribute to free-flap fibrosis, but does not appear to affect the overall risk of complications or revision surgeries. However, additional counseling is warranted if IMN irradiation is likely, as it is potentially associated with increased complications.

INTRODUCTION/BACKGROUND:Dangling protocols are known to vary by surgeon and center, and their specific regimen is often largely based on single surgeon or institutional experience. A systematic review was conducted to derive evidence-based recommendations for dangling protocols according to patient-specific and flap-specific considerations. METHODS:A systematic review was performed using PubMed, Embase-OVID and Cochrane-CENTRAL. Study design, patient and flap characteristics, protocol details, dangling-related complications, and flap success rate were recorded. Studies were graded using the Oxford Center for Evidence-Based Medicine Levels of Evidence Scale. Data heterogeneity precluded quantitative analysis. RESULTS:Eleven articles were included (level of evidence (range):IIb-IV; N (range):8-150; age (range):6-89). Dangling initiation, time, and frequency varied considerably. Flap success rate ranged from 94 to 100%. Active smoking, diabetes, and hypertension are associated with characteristic physiologic changes that require vigilance and potential protocol modification. Early dangling appears to be safe across a variety of free flap locations, sizes, and indications. Axial fasciocutaneous flaps may tolerate more aggressive protocols than muscular flaps. While flaps with single venous anastomosis tolerate dangling, double venous or flow-through anastomoses may provide additional benefit. Major limitations included small sample sizes, uncontrolled study designs, and heterogeneous patient selection, dangling practices, monitoring methods, and outcome measures. CONCLUSIONS:Significant heterogeneity persists in postoperative dangling protocols after lower extremity microvascular reconstruction. Patient comorbidities and flap characteristics appear to affect tolerance to dangling. We propose two different standardized pathways based on risk factors. Clinical vigilance should be exercised in tailoring lower extremity protocols to patients' individual characteristics and postoperative course.