Nerve Wrap for Local Delivery of FK506/Tacrolimus Accelerates Nerve Regeneration.

Peripheral nerve injuries (PNIs) occur frequently and can lead to devastating and permanent sensory and motor function disabilities. Systemic tacrolimus (FK506) administration has been shown to hasten recovery and improve functional outcomes after PNI repair. Unfortunately, high systemic levels of FK506 can result in adverse side effects. The localized administration of FK506 could provide the neuroregenerative benefits of FK506 while avoiding systemic, off-target side effects. This study investigates the utility of a novel FK506-impregnated polyester urethane urea (PEUU) nerve wrap to treat PNI in a previously validated rat infraorbital nerve (ION) transection and repair model. ION function was assessed by microelectrode recordings of trigeminal ganglion cells responding to controlled vibrissae deflections in ION-transected and -repaired animals, with and without the nerve wrap. Peristimulus time histograms (PSTHs) having 1 ms bins were constructed from spike times of individual single units. Responses to stimulus onsets (ON responses) were calculated during a 20 ms period beginning 1 ms after deflection onset; this epoch captures the initial, transient phase of the whisker-evoked response. Compared to no-wrap controls, rats with PEUU-FK506 wraps functionally recovered earlier, displaying larger response magnitudes. With nerve wrap treatment, FK506 blood levels up to six weeks were measured nearly at the limit of quantification (LOQ ≥ 2.0 ng/mL); whereas the drug concentrations within the ION and muscle were much higher, demonstrating the local delivery of FK506 to treat PNI. An immunohistological assessment of ION showed increased myelin expression for animals assigned to neurorrhaphy with PEUU-FK506 treatment compared to untreated or systemic-FK506-treated animals, suggesting that improved PNI outcomes using PEUU-FK506 is mediated by the modulation of Schwann cell activity.

Treatment of Progressive Hemifacial Atrophy by Cartilage Graft and Free Adipofascial Flap Combined with Three-Dimensional Planning.

BACKGROUND: Progressive hemifacial atrophy (PHA) is a rare disease characterized by progressive atrophy of skin, soft tissue, muscles, and underlying bone structures. For severe PHA patients with obvious bone deformities, skeletal framework reconstruction is needed in addition to soft-tissue augmentation. The authors propose a new combinatorial surgical method using rib cartilage graft and free adipofascial flap for restoring facial symmetry. To improve the surgical accuracy, preoperative three-dimensional planning and printing was used. METHODS: Twelve patients with severe facial atrophy were included in the authors' study. Three-dimensional facial image analyses were performed preoperatively to quantify the facial asymmetry. Rib cartilages were harvested and sculptured to the appropriate shape created by three-dimensional planning and fixed to the atrophic bone. The circumflex scapular artery-based adipofascial flap was transplanted to repair soft-tissue deficiency. A residual small monitor flap was left with the adipofascial flap. A revision surgery was performed to perfect the repair if the contour was suboptimal 6 months postoperatively. RESULTS: The adipofascial flaps survived in all 12 patients. All patients achieved good healing without complications. At 1 more year after surgery, the rib cartilage was still in position and rarely absorbed. The morphologic and volumetric difference between the affected side and the unaffected side was improved significantly postoperatively. All patients were satisfied with the results, and no more additional operations were required. CONCLUSION: The combinatorial surgery of rib cartilage graft and free adipofascial flap in the setting of three-dimensional planning and printing can be a good choice in restoring facial symmetry in severe cases of PHA. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Analysis of Postoperative Distal Radius Fracture Outcomes in the Setting of Osteopenia and Osteoporosis for Patients with Comorbid Conditions.

Purpose: Distal radius fractures (DRFs) are among the most common orthopedic injuries, especially in the elderly. A wide variety of approaches have been advocated as successful treatment modalities; yet, there remains variability in practice patterns of DRF in patients with osteoporosis and osteopenia. Using large data set analysis, we sought to determine the risk profile of operative fixation of DRF in patients with low bone mineral density. Methods: A commercially available health care database, PearlDiver, was queried for all patients who underwent open reduction internal fixation of DRFs between 2010 and 2020. The study population was divided into groups based on the presence or absence of osteopenia or osteoporosis and was further classified by patients who were receiving bisphosphonate therapy. Complication rates were calculated, including rates of malunion, surgical site infection, osteomyelitis, hardware failure, and hardware removal. Five-year future fragility fractures were defined in hip, vertebrae, humerus, and wrist fractures. Chi-square analysis and logistic regression were performed to determine an association between these comorbidities and various postoperative complications. Results: A total of 152,926 patients underwent open reduction internal fixation of a DRF during the study period. Chi-square analysis of major complications at 3 months showed a statistically significant increase in malunion in patients with osteopenia (P = .05) and patients with osteoporosis (P = .05) who underwent open reduction internal fixation. Logistic regression analysis at 12 months after surgery demonstrated that osteopenia was associated with an increased risk of hardware failure (P < .0001), hardware removal (P < .0001), surgical site infection (P < .0001), and malunion (P = .004). Osteoporosis was associated with a significantly increased risk of hardware failure (P = .01), surgical site infection (P < .0001), and malunion (P < .0001). Conclusions: We demonstrated, using large data set analysis, that DRF patients with osteopenia and osteoporosis are predicted to be at increased risk of multiple postoperative complications, and thus, bone density should be strongly considered in treatment planning for these patients. Type of study/level of evidence: Prognostic III.

Venous Thromboembolism after Deep Inferior Epigastric Perforator Flap Breast Reconstruction: Review of Outcomes After a Postoperative Prophylaxis Protocol.

BACKGROUND: Deep inferior epigastric perforator (DIEP) flap breast reconstruction is among the higher-risk patient groups for venous thromboembolism (VTE) in plastic surgery. Surgeons often opt for a patient-specific approach to postoperative anticoagulation, and the field has yet to come to a consensus on VTE chemoprophylaxis regimens. METHODS: A new chemoprophylaxis protocol was introduced starting March 2019 that involved two weeks of treatment with enoxaparin, regardless of patient risk factors. A retrospective chart review was conducted on all patients who underwent DIEP flap breast reconstruction at our institution between January 2014 and March 2020. Patients were grouped based on whether they enrolled in the new VTE protocol in the postoperative period or not. Patient demographics, prophylaxis type, and outcomes data were recorded, retrospectively. The primary outcome measure was postoperative VTE incidence. RESULTS: Risk of VTE was significantly higher in patients discharged without VTE prophylaxis compared to patients discharged with prophylaxis (3.7% vs. 0%, p = 0.03). Notably, zero patients in the VTE prophylaxis group developed a DVT or PE. Additionally, the risk of a VTE event was 25 times greater in patients with a Caprini score greater than or equal to 6 (p=0.0002). CONCLUSIONS: We demonstrate the successful implementation of a two-week VTE chemoprophylaxis protocol in DIEP flap breast reconstruction patients that significantly reduces the rate of VTE while not affecting the rate of hematoma complications.

In vivo MRI evaluation of anterograde manganese transport along the visual pathway following whole eye transplantation.

BACKGROUND: Since adult mammalian retinal ganglion cells cannot regenerate after injury, we have recently established a whole-eye transplantation (WET) rat model that provides an intact optical system to investigate potential surgical restoration of irreversible vision loss. However, it remains to be elucidated whether physiological axoplasmic transport exists in the transplanted visual pathway. NEW METHOD: We developed an in vivo imaging model system to assess WET integration using manganese-enhanced magnetic resonance imaging (MEMRI) in rats. Since Mn2+ is a calcium analogue and an active T1-positive contrast agent, the levels of anterograde manganese transport can be evaluated in the visual pathways upon intravitreal Mn2+ administration into both native and transplanted eyes. RESULTS: No significant intraocular pressure difference was found between native and transplanted eyes, whereas comparable manganese enhancement was observed between native and transplanted intraorbital optic nerves, suggesting the presence of anterograde manganese transport after WET. No enhancement was detected across the coaptation site in the higher visual areas of the recipient brain. COMPARISON WITH EXISTING METHODS: Existing imaging methods to assess WET focus on either the eye or local optic nerve segments without direct visualization and longitudinal quantification of physiological transport along the transplanted visual pathway, hence the development of in vivo MEMRI. CONCLUSION: Our established imaging platform indicated that essential physiological transport exists in the transplanted optic nerve after WET. As neuroregenerative approaches are being developed to connect the transplanted eye to the recipient's brain, in vivo MEMRI is well-suited to guide strategies for successful WET integration for vision restoration.