Standard Fixed Enoxaparin Dosing for Venous Thromboembolism Prophylaxis Leads to Low Peak Anti-Factor Xa Levels in Both Head and Neck and Breast Free Flap Patients.

BACKGROUND: Venous thromboembolism (VTE) is a serious complication, particularly in cancer patients undergoing free flap reconstruction. Subcutaneous enoxaparin is the conventional prophylaxis for VTE prevention, and serum anti-factor Xa (afXa) levels are being increasingly used to monitor enoxaparin activity. In this study, free flap patients receiving standard enoxaparin prophylaxis were prospectively followed to investigate postoperative afXa levels and 90-day VTE and bleeding-related complications. METHODS: Patients undergoing free tissue transfer during an 8-month period were identified and prospectively followed. Patients received standard fixed enoxaparin dosing at 30 mg twice daily in head and neck (H&N) and 40 mg daily in breast reconstructions. Target peak prophylactic afXa range was 0.2 to 0.5 IU/mL. The primary outcome was the occurrence of 90-day postoperative VTE- and bleeding-related events. Independent predictors of afXa level and VTE incidence were analyzed for patients that met the inclusion criteria. RESULTS: Seventy-eight patients were prospectively followed. Four (5.1%) were diagnosed with VTE, and six (7.7%) experienced bleeding-related complications. The mean afXa levels in both VTE patients and bleeding patients were subprophylactic (0.13 ± 0.09 and 0.11 ± 0.07 IU/mL, respectively). Forty-six patients (21 breast, 25 H&N) had valid postoperative peak steady-state afXa levels. Among these, 15 (33%) patients achieved the target prophylactic range: 5 (33%) H&N and 10 (67%) breast patients. The mean afXa level for H&N patients was significantly lower than for breast patients (p = 0.0021). Patient total body weight was the sole negative predictor of afXa level (R 2 = 0.47, p < 0.0001). CONCLUSION: Standard fixed enoxaparin dosing for postoperative VTE prophylaxis does not achieve target afXa levels for the majority of our free flap patients. H&N patients appear to be a particularly high-risk group that may require a more personalized and aggressive approach. Total body weight is the sole negative predictor of afXa level, supporting a role for weight-based enoxaparin dosing.

Head and Neck Microsurgeon Practice Patterns and Perceptions Regarding Venous Thromboembolism Prophylaxis.

BACKGROUND: Patients undergoing head and neck (H&N) microvascular reconstruction comprise a population at high risk for venous thromboembolism (VTE). Free flap and VTE thromboprophylaxis may coincide but tend to vary from surgeon to surgeon. This study identifies VTE prophylaxis patterns and perceptions among H&N microsurgeons in the United States. METHODS: An online survey on VTE prophylaxis practice patterns and perceptions was emailed to 172 H&N microsurgeons in the United States using an anonymous link. RESULTS: There were 74 respondents (43% response rate). These surgeons completed residencies in otolaryngology (59%), plastic surgery (31%), and oral maxillofacial surgery (7%). Most underwent fellowship training (95%) and have practiced at an academic center (97%) for at least 6 years (58%), performing an average of 42 ± 31 H&N free flap cases per year (range = 1-190). Most adhered to general VTE prophylaxis guidelines (69%) while 11% did not and 20% were unsure. Nearly all surgeons (99%) would provide prophylactic anticoagulation, mostly in the form of subcutaneous heparin (51%) or enoxaparin (44%); 64% additionally used aspirin, while 4% used aspirin alone. The majority of surgeons (68%) reported having postoperative VTE complications, with six surgeons (8%) reporting patient deaths due to pulmonary embolism. A third of the surgeons have encountered VTE prophylaxis-related adverse bleeding events, but most still believe that chemoprophylaxis is important for VTE prevention (92%). While 35% of surgeons were satisfied with their current practice, most would find it helpful to have official prophylactic anticoagulation guidelines specific to H&N free flap cases. CONCLUSION: The majority of microsurgeons experienced postoperative VTE complications after H&N free flap reconstruction despite the routine use of prophylactic anticoagulation. Though bleeding events are a concern, most surgeons believe chemoprophylaxis is important for VTE prevention and would welcome official guidelines specific to this high-risk population.

Closed-Loop Continuous Hand Control via Chronic Recording of Regenerative Peripheral Nerve Interfaces.

Loss of the upper limb imposes a devastating interruption to everyday life. Full restoration of natural arm control requires the ability to simultaneously control multiple degrees of freedom of the prosthetic arm and maintain that control over an extended period of time. Current clinically available myoelectric prostheses do not provide simultaneous control or consistency for transradial amputees. To address this issue, we have implemented a standard Kalman filter for continuous hand control using intramuscular electromyography (EMG) from both regenerative peripheral nerve interfaces (RPNI) and an intact muscle within non-human primates. Seven RPNIs and one intact muscle were implanted with indwelling bipolar intramuscular electrodes in two rhesus macaques. Following recuperations, function-specific EMG signals were recorded and then fed through the Kalman filter during a hand-movement behavioral task to continuously predict the monkey's finger position. We were able to reconstruct continuous finger movement offline with an average correlation of and a root mean squared error (RMSE) of 0.12 between actual and predicted position from two macaques. This finger movement prediction was also performed in real time to enable closed-loop neural control of a virtual hand. Compared with physical hand control, neural control performance was slightly slower but maintained an average target hit success rate of 96.70%. Recalibration longevity measurements maintained consistent average correlation over time but had a significant change in RMSE ( ). Additionally, extracted single units varied in amplitude by a factor of +18.65% and -25.85% compared with its mean. This is the first demonstration of chronic indwelling electrodes being used for continuous position control via the Kalman filter. Combining these analyses with our novel peripheral nerve interface, we believe that this demonstrates an important step in providing patients with more naturalistic control of their prosthetic limbs.

An Evaluation of the Choice for Contralateral Prophylactic Mastectomy and Patient Concerns About Recurrence in a Reconstructed Cohort.

BACKGROUND: Rising contralateral prophylactic mastectomy rates are a subject of national concern. This study assessed (1) factors critical to patients when deciding on contralateral prophylactic mastectomy and (2) patients' quality of life related to concerns about recurrence after unilateral or bilateral breast reconstruction. METHODS: Patients with stage 0 to III breast cancer who underwent unilateral mastectomy or contralateral prophylactic mastectomy and breast reconstruction at a single institution between 2000 and 2012 were identified. Demographic and clinical data were extracted by chart review. Women's fears about breast cancer recurrence were assessed using the Concerns About Recurrence Scale, and motivational factors for contralateral prophylactic mastectomy were identified using the Decisions for Contralateral Prophylactic Mastectomy Survey. RESULTS: Survey responses were received from 157 patients (59%) who underwent unilateral reconstruction and 109 (41%) who underwent bilateral reconstruction. The top 3 reasons for choosing contralateral prophylactic mastectomy were (1) decreasing the risk of contralateral breast disease (97%), (2) peace of mind (96%), and (3) improved survival (93%). Women who chose contralateral prophylactic mastectomy reported significantly greater overall fear and worry compared with the unilateral group, specifically, greater fears of dying and worries about adequately fulfilling roles of daily life (P < 0.05). CONCLUSIONS: Despite no proven survival benefit, women chose contralateral prophylactic mastectomy primarily to optimize oncologic outcomes. Among breast reconstruction patients, women who underwent contralateral prophylactic mastectomy had greater anxiety and overall fear of breast cancer recurrence compared with those who chose unilateral mastectomy. These findings are important to consider when counseling women contemplating contralateral prophylactic mastectomy.