Peroxisomes are required for lipid metabolism and muscle function in Drosophila melanogaster

Peroxisomes are ubiquitous organelles that perform lipid and reactive oxygen species metabolism. Defects in peroxisome biogenesis cause peroxisome biogenesis disorders (PBDs). The most severe PBD, Zellweger syndrome, is characterized in part by neuronal dysfunction, craniofacial malformations, and low muscle tone (hypotonia). These devastating diseases lack effective therapies and the development of animal models may reveal new drug targets. We have generated Drosophila mutants with impaired peroxisome biogenesis by disrupting the early peroxin gene pex3, which participates in budding of pre-peroxisomes from the ER and peroxisomal membrane protein localization. pex3 deletion mutants lack detectible peroxisomes and die before or during pupariation. At earlier stages of development, larvae lacking Pex3 display reduced size and impaired lipid metabolism. Selective loss of peroxisomes in muscles impairs muscle function and results in flightless animals. Although, hypotonia in PBD patients is thought to be a secondary effect of neuronal dysfunction, our results suggest that peroxisome loss directly affects muscle physiology, possibly by disrupting energy metabolism. Understanding the role of peroxisomes in Drosophila physiology, specifically in muscle cells may reveal novel aspects of PBD etiology.

Surgical Complications after Targeted Muscle Reinnervation at a Safety-Net Hospital

BACKGROUND

 Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) can reduce neuroma formation and phantom limb pain (PLP) after lower extremity (LE) amputation. These techniques have not been studied in safety-net hospitals. This study aims to examine the surgical complication rates after TMR and/or RPNI at an academic safety-net hospital in an urban setting.

METHODS

 This was a retrospective review of patients older than 18 years who had prior above-knee guillotine amputation (AKA) or below-knee guillotine amputation (BKA) and underwent stump formalization with TMR and/or RPNI from 2020 to 2022. Demographics, medical history, and operative and postoperative characteristics were collected. The primary outcome was any surgical complication, defined as infection, dehiscence, hematoma, neuroma, or reoperation. Univariate analysis was conducted to identify variables associated with surgical complications and PLP.

RESULTS

 Thirty-two patients met the inclusion criteria. The median age was 52 years, and 75% were males. Indications for amputation included diabetic foot infection (71.9%), necrotizing soft tissue infection (25.0%), and malignancy (3.1%). BKA was the most common indication for formalization (93.8%). Most patients (56.3%) had formalization with TMR and RPNI, 34.4% patients had TMR only, and 9.4% had RPNI alone. The incidence of postoperative complications was 46.9%, with infection being the most common (31.3%). The median follow-up time was 107.5 days. There was no significant difference in demographics, medical history, or operative characteristics between patients who did and did not have surgical complications. However, there was a trend toward higher rates of PLP in patients who had a postoperative wound infection (p = 0.06).

CONCLUSION

 Overall complication rates after LE formalization with TMR and/or RPNI at our academic safety-net hospital were consistent with reported literature. Given the benefits, including reduced chronic pain and lower health care costs, we advocate for the wider adoption of these techniques at other safety-net hospitals.

Cross-institutional Virtual Mock Oral Examination: A New Paradigm?

Mock oral examinations (MOEs) are shown to be valuable in preparation for national board oral examinations. Although traditionally conducted in-person, improved technological advances have supported exploring virtual alternatives. Furthermore, the cornoavirus disease 2019 pandemic has necessitated virtual learning. We hypothesized that the virtual platform would improve and expand the MOE experience to include collaborative institutions while approximating a board examination environment.

Methods

Sixteen senior plastic surgery residents and 14 faculty from three separate programs participated in a cross-institutional virtual MOE. Over a single day, each trainee was evaluated by two faculty from a separate institution on six scenarios, including digitally interactive photographs. Immediate postexamination debriefing with feedback was performed. All participants were subsequently invited to complete an anonymous survey regarding MOE experience, accuracy, and stress level, with responses graded on a Likert scale (1-5).

Results

Twenty-three participants completed the survey, with 87% having prior MOE experience; however, only 26.1% of participants had virtual MOE experience. Most found the virtual platform more convenient (4.18 + 1.18; 5-far more convenient, 1-far less convenient) and less stressful (2.32 + 0.65; 5-far more stressful, 1-far less stressful) than in-person. All participants found the examination fair, and participants found the examination valuable (4.65 + 0.57) in preparing trainees for the American Board of Plastic Surgery oral examination.

Conclusions

The majority of participants found the virtual MOE experience valuable and comparable to in-person. These results reinforce that a virtual MOE provides an acceptable alternative with greater convenience and improved cross-institutional collaborative efforts.

Effectiveness of Risk Analysis Index Frailty Scores as a Predictor of Adverse Outcomes in Lower Extremity Reconstruction

BACKGROUND

 The rising clinical importance of assessing frailty is driven by its predictive capability for postoperative outcomes. This study assesses the effectiveness of RAI-rev (Revised Risk Analysis Index) in predicting adverse outcomes in lower extremity (LE) flap reconstruction.

METHODS

 Analyzing NSQIP (National Surgical Quality Improvement Program) data from 2015 to 2020, we compared demographics, perioperative factors, and 30-day outcomes in all locoregional and free-flap cases. Frailty scores, calculated using RAI-rev, were categorized with <15 as nonfrail and >35 as the most frail. Adjusted odds ratios (aORs) for specific complications were calculated using nonfrail as the reference group. Frailty scores in locoregional flaps were compared with those in free flaps.

RESULTS

 We identified 270 locoregional and 107 free-flap cases. Higher RAI-rev scores in locoregional flaps correlated with increased complications, such as deep surgical site infection (1% nonfrail vs. 20% RAI 31-35), stroke (0% nonfrail vs. 17% most frail), and mortality (0% nonfrail vs. 17% most frail). Locoregional flap cases with RAI-rev scores in the most frail group had a significantly elevated aOR for stroke (51.0, 95% confidence interval [CI]: 1.8-1402.5, p = 0.02), mortality (43.1, 95% CI: 1.6-1167.6, p = 0.03), and any complication (6.8, 95% CI: 1.2-37.4, p = 0.03). In free-flap cases, higher RAI-rev scores were associated with increased complications, with only sepsis showing a statistically significant difference (6% nonfrail vs. 100% most frail; aOR: 42.3, CI: 1.45-1245.3, p = 0.03). Free-flap cases had a significantly lower RAI-rev score compared with locoregional flap cases (14.91 vs. 17.64, p = 0.01).

CONCLUSION

 Elevated RAI-rev scores (>35) correlated with more complications in locoregional flaps, while free-flap reconstruction patients had generally low RAI-rev scores. This suggests that free flaps are less commonly recommended for presumed higher risk patients. The study demonstrates that RAI-rev may be able to serve as a risk calculator in LE reconstruction, aiding in the assessment of candidates for limb salvage versus amputation.

The Hidden Risks of Perioperative Transfusions in Traumatic Lower Extremity Free Flap Reconstruction

BACKGROUND

 Blood transfusions have been associated with surgical complications; however, these studies are not specific to lower extremity (LE) reconstruction. We evaluated the effect of perioperative packed red blood cell (PRBC) transfusions on LE free flap outcomes in trauma patients.

METHODS

 Patients undergoing LE free flap reconstruction following acute injuries from 2016 to 2021 were retrospectively analyzed. The perioperative period for transfusions was defined as ± 3 days from the procedure. Parameters included demographics, perioperative characteristics, and outcomes. Major complications were complications requiring reoperation. Univariate and multivariate analyses were performed to identify associations.

RESULTS

 Of the 205 patients, 48% received PRBCs perioperatively. There was a trend toward higher major complications rate in the transfusion group (19 vs. 10%, p = 0.09). Wound size, injury severity score (ISS), and intraoperative estimated blood loss were greater in the transfusion group (p < 0.01). Preoperative hemoglobin/hematocrit were lower in the transfusion group (p < 0.001). Units of PRBCs transfused were independently associated with major complications on multivariate analysis (odds ratio [OR] = 1.34, confidence interval [CI]: 1.06-1.70, p = 0.015) and length of hospital stay (LOS; OR = 1.05, CI: 1.02-1.08, p = 0.002). Infection, wound size, ISS, and preoperative hemoglobin/hematocrit were independently associated with increased LOS (p < 0.05) but not with major complications.

CONCLUSION

 The number of units of PRBCs given perioperatively was the only variable independently associated with major complications on multivariate analysis and was one of many variables associated with increased LOS. These findings suggest the usage of restrictive transfusion protocols in trauma patients requiring LE reconstruction.

Optimizing Myelomeningocele Repair: Assessing the Role of Synthetic Acellular Dermal Regeneration Templates in Complex Closures

BACKGROUND

Myelomeningoceles threaten newborns with central nervous system infectious risk. While some myelomeningoceles can be repaired fetally, limited donor tissue in newborns makes covering a substantial defect challenging. This study evaluated the effectiveness of acellular dermal regeneration templates (ADRT) in safely healing refractory myelomeningoceles.

METHODS

Seven myelomeningocele repair cases using ADRT (Integra LifeSciences, Plainsboro, NJ) at an academic children's hospital from April 2020 to June 2023 were reviewed. Patients had unsuccessful closure attempts through fetoscopic, postnatal, or revision surgeries by neurosurgery and plastic surgery, leading to complications that required ADRT to protect the dural repair and promote quicker granulation.

RESULTS

The case series included 3 male and 4 female patients, with a median delivery age of 37 weeks (IQR: 33-37). Three underwent fetoscopic repairs, and 4 had postnatal repairs within 48 hours of birth. Six patients required ADRT placement due to failed primary repair. One patient failed fetoscopic closure and required immediate ADRT placement following an emergent cesarean delivery. The median wound size covered was 12 cm2 (range, 4-20 cm2), and the median hospital stay was 84 days (IQR: 43-105). Three weeks post-ADRT placement, 4 patients showed healthy granulation tissue, and the external silicone layer was removed. Three patients needed additional ADRT for complete wound coverage and successful granulation. After granulation, all wounds eventually epithelialized by secondary intention, with no postoperative infection or wound dehiscence observed.

CONCLUSIONS

ADRT can aid in wound healing and protect dural repair in myelomeningoceles, offering a viable option for complex or failed primary closures with limited donor tissue.