Evaluation of peripheral nerve regeneration in Murphy Roths Large mouse strain following transection injury.

Aim: Murphy Roths Large (MRL/MpJ) mice have demonstrated the ability to heal with minimal or no scar formation in several tissue types. In order to identify a novel animal model, this study sought to evaluate whether this attribute applies to peripheral nerve regeneration. Materials & methods: This was a two-phase study. 6-week-old male mice were divided into two interventional groups: nerve repair and nerve graft. The MRL/MpJ was compared with the C57BL/6J strain for evaluation of both functional and histological outcomes. Results: MRL/MpJ strain demonstrated superior axon myelination and less scar formation, however functional outcomes did not show significant difference between strains. Conclusion: Superior histological outcomes did not translate into superior peripheral nerve regeneration in MRL/MpJ strain.

A Systematic Review of the Reported Complications Related to Facial and Upper Extremity Vascularized Composite Allotransplantation.

INTRODUCTION: Twenty three years after the first successful upper extremity transplantation, the role of vascularized composite allotransplantation (VCA) in the world of transplantation remains controversial. Face and upper extremity reconstruction via transplantation have become successful options for highly selected patients with severe tissue and functional deficit when conventional reconstructive options are no longer available. Despite clear benefit in these situations, VCA has a significant potential for complications that are more frequent when compared to visceral organ transplantation. This study intended to perform an updated systematic review on such complications. MATERIALS AND METHODS: MEDLINE database via PubMed, Embase and Cochrane Library were searched. Face and upper extremity VCA performed between 1998 and 2021 were included in the study. Relevant media and press conferences reports were also included. Complications related to face and upper extremity VCA were recorded and reviewed including their clinical characteristics and complications. RESULTS: One hundred fifteen patients underwent facial (43%) or upper extremity (57%) transplantation. Overall, the surgical complication rate was 23%. Acute and chronic rejection was identified in 89% and 11% of patients, respectively. Fifty eight percent of patients experienced opportunistic infection. Impaired glucose metabolism was the most common immunosuppression-related complication other than infection. Nineteen percent of patients ultimately experienced partial or complete allograft loss. CONCLUSIONS: Complications related to VCA are a significant source of morbidity and potential mortality. Incidence of such complications is higher than previously reported and should be strongly emphasized in patient consent process. Strict patient selection criteria, complex preoperative evaluation, consideration of alternatives, and thorough disclosure to patients should be routinely performed prior to VCA indication.

Twenty Years of Abdominal Wall Allotransplantation: A Systematic Review of the Short- and Long-Term Outcomes.

BACKGROUND: Abdominal wall allotransplantation following intestinal and multivisceral transplant procedures has proven to be successful in achieving adequate closure in patients in whom other techniques have proven inadequate. Thus far, the focus of these abdominal wall allotransplants has been on graft and overall patient survival following surgery and the implementation of immunosuppression. The purpose of this study was to review the outcomes of abdominal wall allotransplantation reported in the literature. METHODS: The PubMed database was queried, and 2595 articles were found. Search criteria used were "abdominal wall transplant" and "abdominal wall allotransplant." Of these, eight met inclusion/exclusion criteria. RESULTS: In the present study, eight publications were identified reporting abdominal wall allotransplants, for a total of 38 full-thickness abdominal wall allotransplantations performed worldwide. All studies reported abdominal wall allotransplantation in combination with visceral organ allotransplantation. Abdominal wall allotransplantations reported thus far have been nonneurotized. Abdominal wall allotransplantations have proven to be beneficial both in terms of abdominal wall closure and acting as a sentinel marker for rejection for underlying visceral organ allotransplantation. The success of abdominal wall allotransplants and their long-term survival has introduced the question of functionality and long-term durability. Cadaveric studies have shown that it is possible to neurotize abdominal wall allotransplants, and future direction toward neurotized abdominal wall allotransplantation requires tools to assess functional outcomes of these transplants. CONCLUSIONS: Abdominal wall allotransplantation is an important reconstructive option when abdominal wall closure is challenging and should be considered in combination with visceral organ allotransplantations. There may be potential benefit in neurotizing the abdominal wall allotransplant for functional use, and future studies should aim to include functional outcomes.

Central versus peripheral nervous system regeneration: is there an exception for cranial nerves?

There exists a dichotomy in regenerative capacity between the PNS and CNS, which poses the question - where do cranial nerves fall? Through the discussion of the various cells and processes involved in axonal regeneration, we will evaluate whether the assumption that cranial nerve regeneration is analogous to peripheral nerve regeneration is valid. It is evident from this review that much remains to be clarified regarding both PNS and CNS regeneration. Furthermore, it is not clear if cranial nerves follow the PNS model, CNS model or possess an alternative novel regenerative process altogether. Future research should continue to focus on elucidating how cranial nerves regenerate; and the various cellular interactions, molecules and pathways involved.

Altmetric Attention Score: Evaluating the Social Media Impact of Burn Research.

Traditional measures of scholarly impact (ie, impact factor, citation rate) do not account for the role of social media in knowledge dissemination. The Altmetric Attention Score (AAS) tracks the online sharing activity of articles on platforms such as Twitter and Facebook. All 285 original scientific articles published in Journal of Burn Care & Research and Burns from January to December 2017 were obtained from official journal websites. Article characteristics extracted include AAS; number of Twitter, Facebook, and news outlet mentions; subject of study and study design; number of citations; number of authors and academic institutions; and others. The average AAS for all articles was 6.1 (SD: 48; range: 0 to 611) in which 156 (55%) of those had Twitter mentions. The mean AAS for Journal of Burn Care & Research and Burns were 7.7 (SD: 54; range: 0 to 536) and 5.3 (SD: 45; range: 0 to 611), respectively. There was a weak, positive correlation between AAS and citation count for all articles (ρ = 0.12; P = .049), and this finding was consistent for Journal of Burn Care & Research (ρ = 0.21; P = .039) and Burns (ρ = 0.15; P = .038) individually. The weak correlation between the two metrics supports that AAS and citation count capture the attention of different audiences. In addition, studies discussing skin grafting were associated with higher average AAS (ß: 29 [95% CI: 4.2 to 54]; P = .022). Overall, our findings support using both AAS and traditional bibliometrics to assess article impact.

Emerging electron microscopy and 3D methodologies to interrogate Staphylococcus aureus osteomyelitis in murine models.

Recent breakthroughs in our understanding of orthopaedic infections have come from advances in transmission electron microscopy (TEM) imaging of murine models of bone infection, most notably Staphylococcus aureus invasion and colonization of osteocyte-lacuno canalicular networks of live cortical bone during the establishment of chronic osteomyelitis. To further elucidate this microbial pathogenesis and evaluate the mechanism of action of novel interventions, additional advances in TEM imaging are needed. Here we present detailed protocols for fixation, decalcification, and epoxy embedment of bone tissue for standard TEM imaging studies, as well as the application of immunoelectron microscopy to confirm S. aureus occupation within sub-micron canaliculi. We also describe the first application of the novel Automated-Tape-UltraMicrotome system with three-dimensional reconstruction and volumetric analyses to quantify S. aureus occupation within the osteocyte-lacuno canalicular networks. Reconstruction of the three-dimensional volume broadened our perspective of S. aureus colonization of the canalicular network and, surprisingly, revealed adjacent noninfected canaliculi. This observation has led us to hypothesize that viable osteocytes of the osteocyte-lacuno canalicular networks respond and resist infection, opening future research directions to explain the paradox of adjacent uninfected canaliculi and life-long deep bone infection in patients with chronic osteomyelitis.

Predictors of cost for posterior spinal fusion in adolescent idiopathic scoliosis.

STUDY DESIGN: Single-center retrospective review of pediatric patients who underwent posterior spinal fusion for adolescent idiopathic scoliosis (AIS). OBJECTIVE: To determine what clinical and operative factors influence inflation-adjusted hospital costs of posterior spine fusion surgery for AIS. With rising healthcare costs and the advent of bundled payments, it is essential understand the predictors of costs for surgical procedures. We sought to determine the components of hospital costs for AIS posterior spine fusion surgery using standardized, inflation-adjusted, line-item costs for services and procedures. METHODS: The study population comprised 148 AIS patients who underwent spinal fusion surgery at a large tertiary care center between 2009 and 2016. Data on medical characteristics, curve type, curve magnitude, number of screws and the number of levels was collected through manual chart review of X-rays and medical records. Hospital costs from admission until discharge were retrieved from an institutional database that contained line-item details of all procedures and services billed during the hospital episode. Bottom-up microcosting valuation techniques were used to generate standardized inflation-adjusted estimates of costs and standard deviations in 2016 dollars. RESULTS: Mean cost of AIS surgery was $48,058 ± 9379. Physician fees averaged 15% of the total cost ($7045 ± 1732). Implant costs and surgical/anesthesia/surgeon's fees accounted for over 70% of the hospital costs. Mean number of screws was 16 ± 4.5, mean number of levels fused was 11.2 ± 2.2, and the mean implant density (screws per level fused) was 1.45 ± 0.35. On multivariate analysis, the number of screws per level fused, number of levels fused, curve magnitude and length of stay were all significantly associated with hospital costs (p < 0.01). CONCLUSIONS: Bundled payments for AIS surgery should include adjustments for number of levels fused and curve size. Areas for cost savings include further reduction in implant costs, shortening length of stay, and reducing intraoperative costs. LEVEL OF EVIDENCE: III.

Outcome measures of facial nerve regeneration: A review of murine model systems.

Animal models of nerve function have been subject to extensive study in order to understand and investigate methods which may improve axon regeneration and promote functional outcomes following nerve injury and repair. As the facial nerve is a cranial nerve, there is mounting evidence that cranial nerve regeneration differs from peripheral, and outcome models specifically addressing the facial nerve are required. Murine models are the most commonly utilized, with a variety of methods employed to measure the actions of whisking, eye closure, or ear movement as indicators of facial nerve regeneration. Each method of measurement is reviewed in terms of validity, strengths, limitations, and the specific outcome data provided. The authors propose that prior to choosing an outcome model, the goals and objectives of a planned study should be well defined, as various outcome measures may be useful depending on the information which is desired. The aim of this paper, therefore, is to provide the reader with a concise review which may facilitate project design.