Targeted Muscle Reinnervation in Children: A Case Report and Brief Overview of the Literature.

Absence of the proximal upper limb, whether congenital or acquired, has a profound impact on quality of life. Targeted muscle reinnervation (TMR) was originally developed to improve functional control over myoelectric prostheses; however, it has also been shown to decrease phantom limb pain and neuroma pain as well as prevent neuroma formation. In children, whose rates of prosthetic use are considerably lower than adults, the effects of amputation on limb function can be devastating. To date, there is very little literature regarding the use of TMR in children. In this case report, we review the current literature and present the case of a 9-year-old boy with a transhumeral amputation secondary to a traumatic injury who underwent acute TMR at the time of wound closure. At 22 months follow-up, the patient is doing well with minimal pain, no evidence of neuroma formation, and signs of muscle reinnervation.

Amputations versus Salvage: Reconciling the Differences.

BACKGROUND: There are many factors to consider when choosing between amputations versus salvage in lower extremity reconstructive surgery. Postoperative functionality and survival benefit are critical factors when deciding between limb salvage and amputation. METHODS: In this review, we present the evidence and the risks and benefits between these two options in the setting of the acute, trauma population and the chronic, diabetes population. RESULTS: The trauma population is on average young without significant comorbidities and with robust vasculature and core strength for recovery. Therefore, these patients can often recover significant function with anamputation and prosthesis. Amputation can therefore be the more desirable in this patient population, especially in the case of complete traumatic disruption, unstable patients, high risk of extensive infection, and significant nerve injury. However, traumatic lower extremity reconstruction is also a viable option, especially in the case of young patients and those with intact plantar sensation and sufficient available tissue coverage. The diabetic population with lower extremity insult has on average a higher comorbidity profile and often lower core strength. These patients therefore often benefit most from reconstruction to preserve limb length and improve survival. However, amputation may be favored for diabetics that have no blood flow to the lower extremity, recalcitrant infection, high-risk comorbidities that preclude multiple operations, and those with end stage renal disease. CONCLUSION: Many patient-specific factors should be considered when deciding between amputation vs. salvage in the lower extremity reconstruction population.

Day-of-Free Tissue Transfer Qualitative Cultures Do Not Predict Limb Salvage Outcomes.

BACKGROUND: Successful free tissue transfer is critical for lower extremity salvage in the chronic wound population. The rates of lower extremity free tissue transfer success lag behind those for other anatomical sites. The aim of this study was to evaluate whether positive qualitative day-of-free tissue transfer cultures or pathogen virulence negatively impacts short- and long-term outcomes of lower extremity free tissue transfer. METHODS: Between April of 2011 and January of 2018, 105 lower extremity free tissue transfer procedures were performed. Growth level and speciation were identified from qualitative cultures taken during free tissue transfer. The relationship between demographics, comorbidities, culture data, postoperative infection, free tissue transfer survival, and long-term limb salvage was examined using logistic regression. RESULTS: The median Charlson Comorbidity Index was 3. Intraoperative free tissue transfer cultures were positive in 39.1 percent. Flap survival was 93.3 percent. Postoperative infection developed in 12.4 percent. The limb salvage rate was 81.0 percent. Positive culture was not significant for flap survival, postoperative infection, or amputation. Cultures positive for Enterococcus species had a significant relationship with flap success (OR, 0.08; p = 0.01) and amputation (OR, 7.32; p = 0.04). Insufficient antimicrobial coverage had a significant relationship with postoperative infection (OR, 6.56; p = 0.01) despite the lack of pathogen concordance. On multivariate analysis, postoperative infection (OR, 12.85; p < 0.01) and Charlson Comorbidity Index were predictive of eventual amputation (OR, 1.44; p = 0.01). CONCLUSIONS: Positive day-of-free tissue transfer cultures, regardless of pathogen, had limited predictive value for short- and long-term outcomes of free tissue transfer in the authors' cohort. These findings call for a broader multicenter prospective analysis and consideration of health care-associated infections and their impact on limb salvage outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Free Anterolateral Thigh Versus Vastus Lateralis Muscle Flaps for Coverage of Lower Extremity Defects in Chronic Wounds.

INTRODUCTION: The thigh has been called the reconstructive warehouse. The anterolateral thigh (ALT) and vastus lateralis (VL) flaps are popular options for free tissue transfer in lower extremity reconstruction. We sought to review the largest experience of these flaps in the chronic wound population. METHODS: We retrospectively reviewed patients who underwent lower extremity reconstruction using ALT or VL flaps by a single surgeon between 2012 and 2018. RESULTS: Fifty ALT and 34 VL flaps were identified. Comorbidities were similar between groups with the exception of body mass index (ALT, 26.8; VL, 30.1; P = 0.0121). There was also a significant difference rate of independent ambulation preoperatively (ALT, 98.0%; VL, 85.3%; P = 0.0375). An adjunct was needed for recipient site coverage in 31.5% (19/50) of ALT patients and 100% (34/34) of VL patients. Of the patients who received skin grafts, delayed placement was more frequent in the ALT (53.3%) versus VL cohort (18.2%) (P = 0.0192). Median graft take and the rate of skin graft revision were not statistically different. Flap success rates were similar: ALT, 92.0%; and VL, 94.1%. Overall complication rates were not significantly different: ALT, 26.0%; and VL, 38.2%. Infectious complications were also comparable. Subsequent debulking procedures were performed on 8.0% of ALT flaps and 11.8% VL flaps (P = 0.7092). Limb salvage rates were similar between both cohorts (ALT, 82.0%; VL, 88.2%). Ambulation rate was significantly higher for the ALT cohort at 92.0% compared with 73.5% for the VL cohort (P = 0.0216). Median follow-up was similar for both groups. CONCLUSIONS: We present the largest comparison study of ALT and VL flaps in lower extremity salvage. Complication rates, flap success, and limb salvage were similar between the 2 cohorts. Despite a high prevalence of osteomyelitis in both cohorts, there was no difference in infectious complications. Although the need for skin grafting remains an inherent disadvantage of the VL flap, a significant proportion of ALT recipients also needed an adjunct for recipient site coverage. Ambulation rate was significantly greater in the ALT group. However, flap type was no longer significant for ambulation when controlling for preoperative ambulatory status.

Evolution of temporal and spectral dynamics of pathologic high-frequency oscillations (pHFOs) during epileptogenesis.

OBJECTIVE: In temporal lobe epilepsy (TLE), pathologic high frequency oscillations (pHFOs, 200-600 Hz) are present in the hippocampus, especially the dentate gyrus (DG). The pHFOs emerge during a latent period prior to the onset of spontaneous generalized seizures. We used a unilateral suprahippocampal injection of kainic acid (KA) mouse model of TLE to characterize the properties of hippocampal pHFOs during epileptogenesis. METHODS: In awake head-fixed mice, 4-14 days after KA-induced status epilepticus (SE), we recorded local field potentials (LFPs) with 64-channel silicon probes spanning from CA1 alveus to the DG hilus, or with glass pipettes in the DC mode in the CA1 str radiatum. RESULTS: The pHFOs, are observed simultaneously in the CA1 and the DG, or in the DG alone, as early as 4 days post-SE. The pHFOs ride on top of DC deflections, occur during motionless periods, persist through the onset of TLE, and are generated in bursts. Burst parameters remain remarkably constant during epileptogenesis, with a random number of pHFOs generated per burst. In contrast, pHFO duration and spectral dynamics evolve from short events at 4 days post-SE to prolonged discharges with complex spectral characteristics by 14 days post-SE. Simultaneous dural EEG recordings were exceedingly unreliable for detecting hippocampal pHFOs; therefore, such recordings may deceptively indicate a "silent" period even when massive hippocampal activity is present. SIGNIFICANCE: Our results demonstrate that hippocampal pHFOs exhibit a dynamic evolution during the epileptogenic period following SE, consistent with their role in transitioning to the chronic stage of TLE.