Evaluation of MR-neurography in diagnosis and treatment in peripheral nerve surgery of the upper extremity: A matched cohort study.

INTRODUCTION: "Watch and wait"-strategies from 3 to 6 months for peripheral nerve injuries are standard of care in specialized centers. However, this contradiction between delayed decision-making and the demand for fast reinnervation, especially of the motoric endplate, has not yet been overcome. Therefore, this study aimed to investigate the time-sparing effects by accelerated decision-making due to the complementary MR-neurography application combined with established diagnostics like electroneurography and neurosonography from the first admission to the determination of the treatment plan. PATIENTS AND METHODS: A retrospective matched-pair chart review analysis with Supplementary MR-neurography in the period between 2014 and 2017 was designed. Matching was performed by the parameters of nerve type, localization of the nerve injury, patient age, and treatment of the injury. Twenty-nine patients were included and matched in the study. MR-neurography imaging was performed by a 3T magnetic resonance imaging with a sampling perfection with application optimized contrasts using different flip angle evolution short tau inversion recovery sequence for the brachial plexus and gradient echo accurate fast imaging with steady-state free precession sequence for the upper extremity. Time to decision-making was investigated for or against a surgical intervention for patients with or without a Supplementary MR-neurography. RESULTS: In general, MR-neurography accelerated decision-making for 28 days, with results of 37.5 + 5.4 days with Supplementary MR-neurography and 65.3 + 9.7 days without Supplementary MR-neurography (p = .05). Within the first 90 days following trauma, patients with MR-neurography (38.2 ± 7.7 days) benefit under a significant faster decision-making (p = .05) than patients without MR-neurography (79.0 + 14.2 days). After 90 days, no evidence of accelerated decision-making was found with the addition of MR-neurography (p = .6). In 10 of the 29 patients, despite additional electroneurography and neurosonography, no decision could be made and the MR-neurography has been used primarily as a diagnostic tool. CONCLUSION: MR-neurography has significant time-sparing effects on the decision-making for approximately 4 weeks within the first 90 days after the trauma. This may help overcome the paradigm of "watch and wait"-strategies during the first 3-6 months after the peripheral nerve injury.

Video-Assisted Peer Teaching for Surgical Skills Training - Innovative Potential for the Medical Curriculum and Beyond: A Randomized Controlled Trial.

OBJECTIVE: Hygienic healthcare standards are essential for avoiding hospital infections. However, medical students and staff lack training in this field, which may be due to high personnel resources of present educational approaches. Thus, there is an urgent need for a novel and efficient approach. Aim of the study is to compare a newly developed video-assisted peer feedback (VAPF) method for teaching wound dressings to the traditional teaching method with qualified instructor feedback (QIF) with respect to essential learning outcomes. DESIGN, SETTING AND PARTICIPANTS: In this randomized controlled noninferiority trial, 251 medical undergraduates were randomly assigned to one of two interventions (QIF n = 127; VAPF n = 124). In QIF, participants received feedback from a qualified instructor. In VAPF, participants video-recorded each other while performing a wound dressing and gave each other feedback assisted by a standardized checklist. Outcome measures were participants' score in an objective structured practical examination (OSPE) and a written exam after the course. RESULTS: Noninferiority of VAPF (n = 123) compared to QIF (n = 127) was confirmed for both OSPE (QIF: 8.83 ± 1.30; VAPF: 8.88 ± 1.04; mean difference -0.04, 95% CI -0.34 to 0.25) and written exam (QIF: 8.99 ± 1.06; VAPF: 9.14 ± 1.05; mean difference -0.15, 95% CI -0.41 to 0.12). CONCLUSIONS: VAPF is a cost-efficient and viable alternative to QIF commonly used in medical education. It provides comparable training outcomes to the traditional training method with lower personnel investment. VAPF is a promising educational method for improving essential clinical competencies.

Cell-enrichment with olfactory ensheathing cells has limited local extra beneficial effects on nerve regeneration supported by the nerve guide Perimaix.

The reconstruction of peripheral nerve injuries is clinically challenging, and today, the autologous nerve transplantation is still considered as the only gold standard remedy for nerve lesions where a direct nerve coaptation is not possible. Nevertheless, the functional merits of many biomaterials have been tested as potential substitutes for the autologous nerve transplant. One of the strategies that have been pursued is the combination of bioengineered nerve guides with cellular enrichment. In this present study, we combined the previously evaluated collagen-based and microstructured nerve guide Perimaix with olfactory ensheathing cell enrichment. Rat sciatic nerve defects of 20 mm were either bridged by a cell-seeded or nonseeded nerve guide or an autologous nerve transplant. Animals were monitored for 12 weeks for structural and functional parameters. Seeded cells survived on Perimaix, and following implantation aligned along the microstructured Perimaix framework. Axonal densities within the cell-seeded nerve guides were higher than in the nonseeded nerve guides and were comparable to the autograft. Additionally, cell-seeding had local beneficial effects on myelination within the nerve guide, as myelin sheath thickness was enhanced when compared with the empty scaffold. Nevertheless, for bridging the nerve gap of 20 mm, both the cell-seeded as well as nonseeded scaffolds were equally efficient regarding the functional outcome, which did not differ between the autograft, seeded or nonseeded groups. Our data demonstrate that olfactory ensheathing cell enrichment has local effects on nerve regeneration in combination with the Perimaix nerve guide. Surprisingly, for traversing the lesion gap, additional cell-seeding is not crucial.

Pre-differentiation of mesenchymal stromal cells in combination with a microstructured nerve guide supports peripheral nerve regeneration in the rat sciatic nerve model.

Many bioartificial nerve guides have been investigated pre-clinically for their nerve regeneration-supporting function, often in comparison to autologous nerve transplantation, which is still regarded as the current clinical gold standard. Enrichment of these scaffolds with cells intended to support axonal regeneration has been explored as a strategy to boost axonal regeneration across these nerve guides Ansselin et al. (1998). In the present study, 20 mm rat sciatic nerve defects were implanted with a cell-seeded microstructured collagen nerve guide (Perimaix) or an autologous nerve graft. Under the influence of seeded, pre-differentiated mesenchymal stromal cells, axons regenerated well into the Perimaix nerve guide. Myelination-related parameters, like myelin sheath thickness, benefitted from an additional seeding with pre-differentiated mesenchymal stromal cells. Furthermore, both the number of retrogradely labelled sensory neurons and the axon density within the implant were elevated in the cell-seeded scaffold group with pre-differentiated mesenchymal stromal cells. However, a pre-differentiation had no influence on functional recovery. An additional cell seeding of the Perimaix nerve guide with mesenchymal stromal cells led to an extent of functional recovery, independent of the differentiation status, similar to autologous nerve transplantation. These findings encourage further investigations on pre-differentiated mesenchymal stromal cells as a cellular support for peripheral nerve regeneration.