Rationale and design of the peripheral nerve tumor registry: an observational cohort study.

AIM: Peripheral nerve tumors (PNT) are rare lesions. To date, no systematic multicenter studies on epidemiology, clinical symptoms, treatment strategies and outcomes, genetic and histopathologic features, as well as imaging characteristics of PNT were published. The main goal of our PNT Registry is the systematic multicenter investigation to improve our understanding of PNT and to assist future interventional studies in establishing hypotheses, determining potential endpoints, and assessing treatment efficacy. METHODS: Aims of the PNT registry were set at the 2015 Meeting of the Section of Peripheral Nerve Surgery of the German Society of Neurosurgery. A study protocol was developed by specialists in PNT care. A minimal data set on clinical status, treatment types and outcomes is reported by each participating center at initial contact with the patient and after 1 year, 2 years, and 5 years. Since the study is coordinated by the Charité Berlin, the PNR Registry was approved by the Charité ethics committee (EA4/058/17) and registered with the German Trials Registry (www.drks.de). On a national level, patient inclusion began in June 2016. The registry was rolled out across Europe at the 2019 meeting of the European Association of Neurosurgery in Dublin. RESULTS: Patient recruitment has been initiated at 10 centers throughout Europe and 14 additional centers are currently applying for local ethics approval. CONCLUSION: To date, the PNT registry has grown into an international study group with regular scientific and clinical exchange awaiting the first results of the retrospective study arm.

Evaluation of functional nerve recovery with Visual-SSI--a novel computerized approach for the assessment of the static sciatic index (SSI).

Complete nerve transection (neurotmesis) of the rat sciatic nerve is a well-established animal model. The most frequently used behavioural for evaluation of neurotmesis-induced deficits is the walking track analysis with calculation of the sciatic functional index (SFI). More recently, the static sciatic index (SSI) has been developed, which shows a good correlation with the SFI. However, despite all advantages (high accessibility, easy handling, high accuracy, cost-effectiveness), the SSI is still not widely used. We, therefore, developed a novel programme ("Visual-SSI"), which will be made freely available for the assessment of the SSI. As gold-standard for the treatment of neurotmesis-induced nerve gaps, autologous nerve transplantation studies in the rat sciatic nerve model (n=16 [6 weeks], n=8 [12 weeks]) were carried out to test the effectiveness and feasibility of the Visual-SSI software. We observed a significant recovery starting from the pre-operative condition over the 3rd, 6th, 9th weeks until the 12th week after surgery (p<0.05). Theoretically, the SSI can be calculated from both rearing and normal standing position of the rats and we investigated whether the SSI is affected differentially by these positions. We observed no significant differences between animals in a rearing and normal standing stance (p>0.05). The present method combines efficiency (simplicity of use, rapid and economical setup) with accurate and precise quantification of the functional regeneration in the sciatic nerve lesion model of the rat.