Faculty Bibliography

BACKGROUND: Composite mandibular tissue loss results in significant functional impairment and cosmetic deformity. This study classifies patterns of mandibular composite tissue loss and describes a microvascular treatment algorithm. METHODS: A retrospective review of microvascular composite mandibular reconstruction from July of 2005 to April of 2013 by the senior surgeon at the R Adams Cowley Shock Trauma Center and at The Johns Hopkins Hospital yielded 24 patients with a mean follow-up of 17.9 months. Causes of composite mandibular defects included tumors, osteoradionecrosis, trauma, infection, and congenital deformity. Patients with composite tissue loss were classified according to missing subunits. RESULTS: A treatment algorithm based on composite mandibular defects and microvascular reconstruction was developed and used to treat 24 patients. A type 1 defect is a unilateral dentoalveolar defect not crossing the midline and not extending into the angle of the mandible. A type 2 defect is a unilateral defect extending beyond the angle. A type 3 defect is a bilateral defect not involving the angles. A type 4 defect is a bilateral defect with extension into at least one angle. Type 2 defects were the predominant group. Patients had microvascular reconstruction using either fibula flaps (n = 19) or iliac crest flaps (n = 5). Complications included infection, partial necrosis, plate fracture, dehiscence, and microvascular thrombosis. CONCLUSION: This novel classification system and treatment algorithm allows for a consistent and reliable method of addressing composite mandibular defects and focuses on recipient vasculature and donor free flap characteristics. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Background Prolonged operative time has been associated with increased postoperative complications and higher costs. Many academic centers have a designated day for didactics that cause cases to start 1 hour later. The purpose of this study is to analyze the late-start effect of microvascular breast reconstructions on operative duration. Methods A retrospective review was performed on all patients who underwent abdomina-based free flap breast reconstruction from 2007 to 2011 and analyzed by those who had surgery on late-start versus normal-start days. Patient demographics, average operative time, postoperative complications, and individual surgeon effects were analyzed. A Student t-test was used to compare operative times with statistical significance set at p < 0.05. A multivariate regression analysis was performed to control for potential confounders. Results A total of 272 patients underwent 461 free flap breast reconstructions. Twenty-one cases were performed on late-start days and 251 cases were performed on normal-start days. Patient demographics and complications were not statistically different between the groups. The average operative time for all reconstructions was 434.3 minutes. The average operative times were significantly longer for late-start days, 517.6 versus 427.3 minutes (p = 0.002). This was true for both unilateral and bilateral reconstructions (432.8 vs. 350.9 minutes, p = 0.05; 551.5 vs. 461.2 minutes, p = 0.007). There were no differences in perioperative complications and multivariate regression showed no statistically significant relationship of confounders to duration of surgery. Conclusion Starting cases 1 hour later can increase operative times. Although outcomes were not affected, we recommend avoiding lengthy procedures on late-start days.

PURPOSE: This study aimed to evaluate the probability of survival, Weibull modulus, characteristic strength, and failure modes of computer-aided design/computer-assisted manufacture (CAD/CAM) fiber-reinforced composite (FRC) substructures used for implant-supported fixed dental prostheses (ISFDPs). MATERIALS AND METHODS: Three-unit ISFDPs (first molar pontic) fabricated as a monolithic composite piece or as composite veneered on a CAD/CAM FRC substructure with either a 12-mm2 or 3-mm2 connector area (n = 18 each) were subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and the probability of survival were calculated. Fractographic analysis was performed under polarized light and scanning electron microscopy. RESULTS: Fatigue did not accelerate the failure of any group, whereas prosthesis strength was the main factor in increased failure (beta < 1). The probability Weibull contour plot showed no differences between the ISFDPs with 12 mm2 and the monolithic composite ISFDP in characteristic strength (eta = 643.5 N and 742.7 N, respectively) or Weibull modulus (6.7 and 5.8, respectively), whereas both were significantly higher than 3 mm2 (444.91 N and 9.57). The probability of survival was not statistically different between groups at 100,000 mission cycles at 300 N. Differences were observed in fatigue failures above 800 N; monolithic composite ISFDPs failed catastrophically, whereas those with CAD/CAM FRC substructures presented veneer/composite cohesive or adhesive failures. Cracks evolved from the occlusal contact toward the margins of the cohesively failed composite, and in CAD/CAM FRC prostheses, competing failure modes of cracks developing at the connector area with those at the indentation contact were observed. CONCLUSION: The probability of survival did not differ between CAD/CAM FRC with either 3-mm2 or 12-mm2 connector areas, monolithic composite, or metal-ceramic ISFDPs previously tested under the same methodology. However, differences in failure modes were detected between groups.

CONTEXT: Fatigue is a distressing, persistent sense of physical tiredness that is not proportional to a person's recent activity. Fatigue impacts patients' treatment decisions and can limit their self-care activities. While significant interindividual variability in fatigue severity has been noted, little is known about predictors of interindividual variability in initial levels and trajectories of evening fatigue severity in oncology patients receiving chemotherapy (CTX). OBJECTIVES: To determine whether demographic, clinical, and symptom characteristics were associated with initial levels as well as the trajectories of evening fatigue. METHODS: A sample of outpatients with breast, gastrointestinal, gynecological, and lung cancer (N=586) completed demographic and symptom questionnaires a total of six times over two cycles of CTX. Fatigue severity was evaluated using the Lee Fatigue Scale. Hierarchical linear modeling (HLM) was used to answer the study objectives. RESULTS: A large amount of interindividual variability was found in the evening fatigue trajectories. A piecewise model fit the data best. Patients who were White, diagnosed with breast, gynecological, or lung cancer, and who had more years of education, child care responsibilities, lower functional status, and higher levels of sleep disturbance and depression reported higher levels of evening fatigue at enrollment. CONCLUSION: This study identified both non-modifiable (e.g., ethnicity) and modifiable (e.g., child care responsibilities, depressive symptoms, sleep disturbance) risk factors for more severe evening fatigue. Using this information, clinicians can identify patients at higher risk for more severe evening fatigue, provide individualized patient education, and tailor interventions to address the modifiable risk factors.

BACKGROUND: Multiple perfusion assessment technologies exist to identify compromised microvascular free flaps. The effectiveness, operability, and cost of each technology vary. The authors investigated surgeon preference and clinical behavior with several perfusion assessment technologies. METHODS: A questionnaire was sent to members of the American Society for Reconstructive Microsurgery concerning perceptions and frequency of use of several technologies in varied clinical situations. Demographic information was also collected. Adjusted odds ratios were calculated using multinomial logistic regression accounting for clustering of similar practices within institutions/regions. RESULTS: The questionnaire was completed by 157 of 389 participants (40.4 percent response rate). Handheld Doppler was the most commonly preferred free flap-monitoring technology (56.1 percent), followed by implantable Doppler (22.9 percent) and cutaneous tissue oximetry (16.6 percent). Surgeons were significantly more likely to opt for immediate take-back to the operating room when presented with a concerning tissue oximetry readout compared with a concerning handheld Doppler signal (OR, 2.82; p < 0.01), whereas other technologies did not significantly alter postoperative management more than simple handheld Doppler. Clinical decision making did not significantly differ by demographics, training, or practice setup. CONCLUSIONS: Although most surgeons still prefer to use standard handheld Doppler for free flap assessment, respondents were significantly more likely to opt for immediate return to the operating room for a concerning tissue oximetry reading than an abnormal Doppler signal. This suggests that tissue oximetry may have the greatest impact on clinical decision making in the postoperative period.

Cancer pain sends a message. It is frightening to the patient. It heralds progression or recurrence to the oncologist. It is a biological readout of the cancer-nerve interaction for the scientist. Nerves have been considered bystanders within the cancer microenvironment. However, emerging information suggests that nerves are recruited and participate in the carcinogenic process. These newly formed fibers respond to mediators secreted by constituents of the cancer microenvironment. In this manner, these nerves serve as bellwethers and sensors embedded within the cancer. When we rigorously assess patients' cancer pain, we gain insight into the action of cancer. An enhanced understanding of cancer pain offers biological questions that if answered might not only provide relief from cancer pain but might also improve survival.

Differential thermal nociception across inbred mouse strains has genetic determinants. Thermal nociception is largely attributed to the heat/capsaicin receptor TRPV1; however, the contribution of this channel to the genetics of thermal nociception has not been revealed. In this study we compared TRPV1 expression levels and electrophysiological properties in primary sensory neurons and thermal nociceptive behaviors between two (C57BL/6 and BALB/c) inbred mouse strains. Using immunofluorescence and patch-clamp physiology methods, we demonstrated that TRPV1 expression was significantly higher in isolectin B4 (IB4) -positive trigeminal sensory neurons of C57BL/6 relative to BALB/c; the expression in IB4-negative neurons was similar between the strains. Furthermore, using electrophysiological cell classification (current signature method), we showed differences between the two strains in capsaicin sensitivity in IB4-positive neuronal cell types 2 and 13, that were previously reported as skin nociceptors. Otherwise electrophysiological membrane properties of the classified cell types were similar in the two mouse strains. In publicly available nocifensive behavior data and our own behavior data from the using the two mouse strains, C57BL/6 exhibited higher sensitivity to heat stimulation than BALB/c, independent of sex and anatomical location of thermal testing (the tail, hind paw and whisker pad). The TRPV1 selective antagonist JNJ-17203212 inhibited thermal nociception in both strains; however, removing IB4-positive trigeminal sensory neurons with IB4-conjugated saporin inhibited thermal nociception on the whisker pad in C57BL/6, but not in BALB/c. These results suggest that TRPV1 expression levels in IB4-positive type 2 and 13 neurons contributed to differential thermal nociception in skin of C57BL/6 compared to BALB/c.

BACKGROUND: Microvascular reconstruction is the mainstay of treatment in complex scalp defects. The rate of elderly patients requiring scalp reconstruction is increasing, but outcomes in elderly patients are unclear. The purpose of this study was to systematically review the literature pertaining to free tissue transfer for scalp reconstruction in patients older than 65 years to compare outcomes among different free flaps and determine the safety profile of treatment. METHODS: A systematic review of the available literature of patients undergoing microvascular scalp reconstruction was completed. Details for patients 65 years and older were extracted and reviewed for data analysis. RESULTS: A total of 45 articles (112 patients) were included for analysis. Mean age of the patients was 73.3 +/- 6.3 years (men, 69.4 percent; women, 23.4 percent; not reported, 7.2 percent). Mean flap size was 598 cm (range, 81 to 2500 cm). The mean age of patients developing a complication was 72.8 +/- 6.4 years and patients that did not develop a complication was 73.4 +/- 5.5 years (p = 0.684). Overall, periprocedural mortality was 0.9 percent. Flap failures occurred in two cases (1.8 percent). The overall complication rate was 22.3 percent (n = 25). Complications by flap type varied without reaching statistical significance. CONCLUSIONS: Microvascular reconstruction in complex scalp defects is associated with successful outcomes, and chronologic age does not increase mortality or catastrophic flap complications. The most common flaps used to repair scalp defects are anterolateral thigh and latissimus dorsi, but a superior flap type could not be identified.