Mechanisms, interventions at risk and clinical presentation of iatrogenic nerve lesions in trauma patients.

BACKGROUND: Iatrogenic nerve lesions during surgical interventions are avoidable complications that may cause severe functional impairment. Hereby, awareness of physicians and knowledge of structures and interventions at risk is of utmost importance for prevention. As current literature is scarce, we evaluated all patients treated surgically due to peripheral nerve injuries in our specialized nerve center for the presence of iatrogenic nerve lesions. METHODS: We evaluated a total of 5026 patients with peripheral nerve injuries treated over a time period of 8 years in our facility for the prevalence of iatrogenic nerve injuries, their clinical presentations, time to treatment, mechanisms and intraoperative findings on nerve continuity. RESULTS: A total of 360 (6.1%) patients had an iatrogenic cause resulting in 380 injured nerves. 76.6% of these lesions affected the main branch of the injured nerve, which were mainly the radial (30.5%), peroneal (13.7%) and median nerve (10.3%). After a mean delay of 237 ± 344 days, patients presented 23.2% with a motor and 27.9% with a mixed sensory and motor deficit. 72.6% of lesions were in-continuity lesions. Main interventions at risk are displayed for every nerve, frequently concerning osteosyntheses but also patient positioning and anesthesiologic interventions. DISCUSSION: Awareness of major surgical complications such as iatrogenic nerve injuries is important for surgeons. An often-seen trivialization or "watch and wait" strategy results in a huge delay for starting an adequate therapy. The high number of in-continuity lesions mainly in close proximity to osteosyntheses makes diagnosis and treatment planning a delicate challenge, especially due to the varying clinical presentations we found. Diagnostics and therapy should therefore be performed as early as possible in specialized centers capable of performing nerve repair as well as salvage therapies.

Improving outcomes in traumatic peripheral nerve injuries to the upper extremity.

Peripheral nerve lesions of the upper extremity are common and are associated with devastating limitations for the patient. Rapid and accurate diagnosis of the lesion by electroneurography, neurosonography, or even MR neurography is important for treatment planning. There are different therapeutic approaches, which may show individual differences depending on the injured nerve. If a primary nerve repair is not possible, several strategies exist to bridge the gap. These may include autologous nerve grafts, bioartificial nerve conduits, or acellular nerve allografts. Tendon and nerve transfers are also of major importance in the treatment of nerve lesions in particular with long regeneration distances. As a secondary reconstruction, in addition to tendon transfers, there is also the option for free functional muscle transfer. In amputations, the prevention of neuroma is of great importance, for which different strategies exist, such as target muscle reinnervation, regenerative peripheral nerve interface, or neurotized flaps. In this article, we give an overview of the latest methods for the therapy of peripheral nerve lesions.

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.

A single-center retrospective comparison of Duplex ultrasonography versus audible Doppler regarding anterolateral thigh perforator flap harvest and operative times.

INTRODUCTION: We reported on the superiority of preoperative Duplex mapping ("Duplex") over audible Dopplers ("Doppler") in anterolateral thigh perforator (ALT) free flaps for upper extremity reconstruction. To corroborate our findings on a larger cohort, we conducted this present study focusing on surgical efficiency and patient safety. METHODS: 150 consecutive ALT free flaps were divided into 65 cases of preoperative Duplex versus 85 Doppler controls. We first compared patient demographics, operative details, and defect and flap characteristics. We then assessed group differences in the number and course of perforators pursued intraoperatively, flap harvest and operative times, and donor-site complications. Additionally, the impact of the training level of the primary microsurgeon was evaluated. RESULTS: Cases and controls were comparable regarding age (p = .48), sex (p = .81), ASA class (p = .48), and BMI (p = .90). Duplex was associated with an increased likelihood of raising flaps on one single dominant perforator of purely septal course and significant reductions of flap harvest (68 ± 10 min, p < .0001) and operative times (74 ± 16 min, p < .0001), regardless of the experience of the primary microsurgeon. There were strong negative linear correlations between preoperative Duplex and both the flap harvest and operative times (p < .0001). Additionally, while there was no effect on the emergency take-back rate (OR = 1.3, p = .60), revisions were significantly less likely among duplexed patients (OR = 0.15, p = .04). CONCLUSIONS: Preoperative Duplex is associated with a significant reduction in ALT free flap harvest and overall operative times, as well as donor-site revisions as opposed to Doppler planning, regardless of the training level of the primary microsurgeon.

Single incision thenar muscle reconstruction using the free functional pronator quadratus flap.

BACKGROUND: Injuries to the thenar muscle mass or the thenar branch of the median nerve and resulting loss of thumb opposition lead to a massive impairment of hand function. For decades, reconstructive approaches were based on tendon transfers. To broaden the reconstructive repertoire, we present the free functional pronator quadratus flap as a viable alternative for functional reconstruction and provide a specification for its indication. We demonstrate our surgical technique to a single incision reconstruction using the free functional pronator quadratus flap. Based on a series of three patients, which were analyzed for hand function using Kapandji's score and the angle of Bourrel, grip strength and nerve conduction velocity in a two year follow up, we present an indication algorithm. RESULTS: After successful reinnervation of all flaps, we found an improvement of Kapandji's score from 4.3 ± 0.94 preoperatively, to 8.7 ± 0.47 after two years. Accordingly, the angle of Bourrel decreased from 75.75 ± 3.45 degrees to 36.96 ± 3.68 degree. Grip strength also improved from 14 ± 2.2 kg to 26.2 ± 1.2 kg. No impairment of wrist pronation was observed. CONCLUSION: We found excellent functional recovery of thumb opposition and strength, showing similar or even superior results compared to results from tendon transfers. With the benefit of a single incision surgery and therefore minimal donor site morbidity, this free functional muscle transfer is a viable alternative to classic tendon transfers.

A Structured, Microsurgical Training Curriculum Improves the Outcome in Lower Extremity Reconstruction Free Flap Residency Training: The Ludwigshafen Concept.

BACKGROUND: Risk stratification, economic pressure, and a flat learning curve make the realization and development of proper microsurgical skills and competences a challenging task in the daily clinical practice. In previous studies, we were able to show that microsurgical procedures, e.g., free flaps and replantations, are safe training procedures and teachable in daily clinical practice in view of certain issues of risk stratification. The present study aims to evaluate further improvements in terms of safety and complication rates for free flaps as a training procedure after introduction and continuous implementation of a structured in-house training curriculum for microsurgical skills and competences and a 24-hour free accessible microsurgical training facility for the plastic surgery resident. METHODS: This retrospective comparative cohort study was conducted to review whether microsurgical skills for free flaps to the lower extremity can further be improved after implementation of the curriculum and a 24-hour accessible training facility. Therefore, we compared cohort A before (2009-2012) and B after (2014-2017) implementation. Patient demographics, procedural characteristics, and outcome parameters for free tissue transfer of the lower extremity were evaluated. RESULTS: The comparison of both cohorts showed a significantly reduced postoperative complication rate for cohort B (p <0.05). Furthermore, operation time was shorter, and the hospital stay could be significantly decreased (p <0.01). Workhorse flaps for plastic surgical training were the anterior lateral thigh (ALT) flap or the musculus latissimus dorsi (LD) flap. However, even more complex procedures with arteriovenous loops could be safely performed by plastic surgery residents under the supervision of the senior surgeon in exceptional cases. CONCLUSION: The implementation of a regularly held, microsurgical in-house training curriculum with 24-hour accessible training facility improves procedural and outcome parameters for free flaps to the lower extremity for surgical residents and is an elementary part of skills and competency training. However, risk stratification, repeated surgical exposure, expertise, and institutional infrastructures are essential and must be taken into consideration.

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.

Revealing digital nerve lesions-A comprehensive analysis of 2084 cases of a specialized center.

BACKGROUND: Finger nerve injuries have a significant impact on hand function and can result in reduced sensation, pain and impaired coordination. The socioeconomic implications of these injuries include decreased workplace productivity, reduced earning potential, and financial burdens associated with long-term medical treatment and rehabilitation. However, there is a lack of comprehensive literature regarding the incidence, mechanisms, and associated injuries of finger nerve lesions. METHODS: A retrospective analysis was conducted on patients treated at our institution from January 2012 to July 2020. Cases of peripheral finger nerve lesions were identified using the digital hospital information system and ICD-10 Classification. Exclusion criteria included injuries to the median nerve at the carpal tunnel level or superficial branch of the radial nerve. Data were collected using a pseudonymized approach, and statistical analyses were performed using SPSS Statistics (Version 27). RESULTS: A total of 2089 finger nerve lesions were analyzed, with a majority of cases occurring in men. Most injuries97.4 % were caused by trauma, predominantly cut/tear injuries. Isolated finger nerve injuries were more common than multiple nerve injuries, with the index finger being the most frequently affected. Concomitant tendon and vascular injuries were observed in a significant proportion51.7 % of cases. Surgical management included direct nerve coaptation, interposition grafting and neurolysis. DISCUSSION: Finger nerve injuries are the most prevalent type of nerve injury, often resulting from small lacerations. These injuries have substantial societal costs and can lead to prolonged sick leave. Understanding the epidemiology and etiology of finger nerve injuries is crucial for implementing effective preventive measures. Accompanying tendon injuries and the anatomical location of the nerve lesions can impact sensory recovery and treatment outcomes. Proper management of peripheral finger nerve lesions is essential for optimizing functional outcomes and minimizing the impact on daily activities. Treatment options should be tailored to the severity and underlying cause of the nerve injury.

Robot-assisted Microsurgery: Lessons Learned from 50 Consecutive Cases.

Background: The potential of robot-assisted surgery in plastic and reconstructive surgery remains to be established, especially in free tissue transfer. This prospective study aimed to present our experience and findings from the first 50 consecutive cases of robot-assisted microsurgery using the Symani surgical system. Methods: A prospective database was maintained, recording patient demographics and surgical details for all cases of robot-assisted microsurgery in a large academic institution. All surgeons underwent an intensive training program with the Symani surgical system. Results: A total of 50 patients who underwent robot-assisted microsurgical reconstruction were identified. Free microsurgical tissue transfer was performed in 45 cases, targeted muscle reinnervation in four cases, and lymphovenous anastomoses in a single case. A total of 94 robot-assisted anastomoses and coaptations were performed, (46 venous and 30 arterial anastomoses, 16 nerve coaptations, two lymphovenous anastomoses). Six cases involved perforator-to-perforator anastomoses. Ninety-eight percent of attempted anastomoses were completed using the robot. Size-mismatch anastomoses, seen in 37.8% of cases, took significantly longer. Minor complications occurred in three cases and major in six cases. There were three cases of microvascular compromise requiring revision. One partial flap loss and no complete flap loss occurred. Conclusions: Our study highlights the immense potential of robot-assisted microsurgery, and a feasible and effective modality for various microsurgical procedures, with outcomes comparable to those of conventional microsurgery. Despite challenges, such as increased operating times and higher costs, the technology offers significant advantages, such as enhanced precision and motion scaling. We identify a slow learning curve and a necessity for higher caseloads.

Inferior long-term Results of a Prospective Randomized Controlled Trial initially demonstrating enhanced Sensory Nerve Recovery using a Chitosan Nerve Tube.

INTRODUCTION: Traumatic peripheral nerve injuries can result in significant functional impairments and long-term sequelae. This study evaluated the long-term outcomes of a chitosan tube implantation protecting the epineural coaptation after peripheral nerve injuries using two different tube versions (V 1.0 and V 2.0 with different wall thickness and resorption characteristics) compared to a control group. The study focused on pain levels, sensory function, and overall functional outcomes. METHODS: Patients who received tube implantation around direct coaptation sites of digital nerves were prospectively randomized and compared to control patients without additional tube protection. Pain levels, sensory function, grip force, and functional scores were assessed at different time points, ranging from three months to five years after the procedure. Furthermore, biodegradation of the tubes was measured via high-resolution MR-neurography (MRN) and categorized. RESULTS: Long-term evaluation revealed that patients with V 1.0 had higher pain levels compared to the control group after five years. They also reported more symptoms of numbness and hypersensitivity. V 2.0 patients exhibited higher pain levels at three months, which did not persist at six months. However, they showed compromised sensory function, with higher values of two-point discrimination compared to V 1.0 and the control group. No differences were found in grip force or functional scores between the groups. MRI displayed remnants of implants even in long-term follow-up. DISCUSSION: The findings suggest potential limitations due to pain increase and impaired sensory function associated with tube implantation in the long term. However, in the short term, the material seemed to have a protective effect (as published previously). The resorption process was not completed at the end of the observation period of five years. This might explain the prolonged scarring and inferior long-term results. Future research should focus on improving tube materials and design to minimize adverse effects and enhance functional outcomes in patients with peripheral nerve injuries.

Benefit of Adjuvant Mesenchymal Stem Cell Transplantation to Critical-Sized Peripheral Nerve Defect Repair: A Systematic Review and Meta-Analysis of Preclinical Studies.

Critically sized nerve defects cause devastating life-long disabilities and require interposition for reconstruction. Additional local application of mesenchymal stem cells (MSCs) is considered promising to enhance peripheral nerve regeneration. To better understand the role of MSCs in peripheral nerve reconstruction, we performed a systematic review and meta-analysis of the effects of MSCs on critically sized segment nerve defects in preclinical studies. 5146 articles were screened following PRISMA guidelines using PubMed and Web of Science. A total of 27 preclinical studies (n = 722 rats) were included in the meta-analysis. The mean difference or the standardized mean difference with 95% confidence intervals for motor function, conduction velocity, and histomorphological parameters of nerve regeneration, as well as the degree of muscle atrophy, was compared in rats with critically sized defects and autologous nerve reconstruction treated with or without MSCs. The co-transplantation of MSCs increased the sciatic functional index (3.93, 95% CI 2.62 to 5.24, p < 0.00001) and nerve conduction velocity recovery (1.49, 95% CI 1.13 to 1.84, p = 0.009), decreased the atrophy of targeted muscles (gastrocnemius: 0.63, 95% CI 0.29 to 0.97 p = 0.004; triceps surae: 0.08, 95% CI 0.06 to 0.10 p = 0.71), and promoted the regeneration of injured axons (axon number: 1.10, 95% CI 0.78 to 1.42, p < 0.00001; myelin sheath thickness: 0.15, 95% CI 0.12 to 0.17, p = 0.28). Reconstruction of critically sized peripheral nerve defects is often hindered by impaired postoperative regeneration, especially in defects that require an autologous nerve graft. This meta-analysis indicates that additional application of MSC can enhance postoperative peripheral nerve regeneration in rats. Based on the promising results in vivo experiments, further studies are needed to demonstrate potential clinical benefits.

Hopeless Neuroma-The Neurotized Free Flap Tissue Augmentation as Salvage Therapy-A Concept and Clinical Demonstration.

Therapy-resistant neuroma pain is a devastating condition for patients and surgeons. Although various methods are described to surgically deal with neuromas, some discontinuity and stump neuroma therapies have anatomical limitations. It is widely known that a neurotizable target for axon ingrowth is beneficial for dealing with neuromas. The nerve needs "something to do". Furthermore, sufficient soft tissue coverage plays a major role in sufficient neuroma therapy. We aimed, therefore, to demonstrate our approach for therapy of resistant neuromas with insufficient tissue coverage using free flaps, which are sensory neurotized via anatomical constant branches. The central idea is to provide a new target, a new "to do" for the painful mislead axons, as well as an augmentation of deficient soft tissues. As indication is key, we furthermore demonstrate clinical cases and common neurotizable workhorse flaps.

Avoiding scar tissue formation of peripheral nerves with the help of an acellular collagen matrix.

INTRODUCTION: Extensive scar tissue formation after peripheral nerve injury or surgery is a common problem. To avoid perineural scarring, implanting a mechanical barrier protecting the nerve from inflammation processes in the perineural environment has shown promising results for functional recovery. This study investigates the potential of an acellular collagen-elastin matrix wrapped around a peripheral nerve after induction of scar tissue formation. MATERIALS AND METHODS: In the present study, 30 Lewis rats were separated into three groups and sciatic nerve scarring was induced with 2.5% glutaraldehyde (GA-CM) or 2.5% glutaraldehyde with a supplemental FDA-approved acellular collagen-elastin matrix application (GA+CM). Additionally, a sham group was included for control. Nerve regeneration was assessed by functional analysis using the Visual Statisc Sciatic Index (SSI) and MR neurography during the 12-week regeneration period. Histological and histomorphometry analysis were performed to evaluate the degree of postoperative scar tissue formation. RESULTS: Histological analysis showed an extensive scar tissue formation for GA-CM. Connective tissue ratio was significantly (p < 0.009) reduced for GA+CM (1.347 ± 0.017) compared to GA-CM (1.518 ± 0.057). Similarly, compared to GA+CM, MR-Neurography revealed extensive scar tissue formation for GA-CM with a direct connection between nerve and paraneural environment. Distal to the injury site, quantitative analysis presented significantly higher axon density (p = 0.0145), thicker axon diameter (p = 0.0002) and thicker myelinated fiber thickness (p = 0.0008) for GA+CM compared to GA-CM. Evaluation of functional recovery revealed a significantly faster regeneration for GA+CM. CONCLUSION: The supplemental application of an acellular collagen-elastin matrix showed beneficial effects in histological, radiological, and functional analysis. Therefore, applying a collagen-elastin matrix around the nerve after peripheral nerve injury or surgery may have beneficial effects on preventing scar tissue formation in the long run. This represents a feasible approach to avoid scar tissue formation in peripheral nerve surgery.

Objective Burn Scar Assessment in Clinical Practice Using the Cutometer©: Introduction and Validation of a Standardized Measurement Protocol.

An objective burn scar assessment is essential to informed therapeutic decision-making and to monitor scar development over time. However, widely employed scar rating scales show poor inter-rater reliability. For this study we developed a standardized measurement protocol for the Cutometer© applicable for objective burn scar assessment in everyday clinical practice. We developed a measurement protocol for the Cutometer© MPA 580 including a scar site relocation technique based on anatomical landmarks. The protocol emerged through several steps: Identifying key factors for valid and reliable measurements, preliminary testing, specification of technical details, refining the protocol and final testing. Consecutively, the protocol was validated for inter-rater reliability by assessing 34 burn scars in 17 patients by four clinicians and computing an Intra-class Correlation Coefficient (ICC). Parameter R0, representing scar pliability, was identified as the best suited output parameter yielding excellent inter-rater reliability for average measures (ICC 0.92 [95% CI 0.86; 0.96]) and acceptable reliability for single measures (ICC: 0.74 [0.61; 0.84]). The pressure applied on the measuring probe was identified as an influential confounding factor for reliable measurements. Rater gender did not influence reliability of measurements. The introduced standardized measurement protocol for the Cutometer© MPA 580 enables an objective and reliable burn scar assessment for clinical as well as research purposes.

Peripheral nerve injuries in children-prevalence, mechanisms and concomitant injuries: a major trauma center's experience.

BACKGROUND: Peripheral nerve injuries are severe conditions with potential lifelong impairment, which is especially meaningful for the pediatric population. Knowledge on prevalence, injury mechanisms and concomitant injuries is, therefore, of utmost importance to increase clinician awareness and enable early diagnosis and treatment. As current literature on pediatric nerve lesions and concomitant injuries is scarce, we aimed to analyze all details of our patient population. METHODS: A total of 110 667 patients treated at our level 1 trauma center from 2012 to 2021 were evaluated for pediatric peripheral nerve injuries, causes, concomitant injuries and assessed for lesion classification (in continuity, partial lesion, dissection) and further relevant intraoperative findings. RESULTS: We found 5026 patients of all ages with peripheral nerve lesions, whereof 288 were pediatric, resulting in a prevalence of 5.7% of pediatric patients with nerve injuries. Mean age was 12.4 ± 4.6 years. Most common lesions were digital nerves (48.2%), followed by median (14.9%), ulnar (14.6%), radial (8.8%), peroneal nerve (5.2%) and brachial plexus injuries (2.1%). Of all pediatric nerve injuries, 3.8% were iatrogenic, only 30.2% had preserved continuity and 47.3% a concomitant vessel injury. Fractures were accompanied in 22.6%. DISCUSSION: We observed that a large proportion of injures had complete transections, often accompanied by concomitant vessel injuries especially in distally located injuries, highlighting the importance of early surgical exploration. Radial, ulnar and lower extremity nerve injuries were often associated with fractures. Early surgical nerve repair is key to improve motor and sensory outcomes. Knowledge on mechanisms and concomitant injuries facilitates timely diagnosis and treatment, thereby potentially preventing lifelong impairment.

Shielding the Nerve: A Systematic Review of Nerve Wrapping to Prevent Adhesions in the Rat Sciatic Nerve Model.

BACKGROUND: Peripheral nerve pathology is frequently encountered in clinical practice among peripheral nerve and extremity surgeons. One major factor limiting nerve regeneration and possibly leading to revision surgeries is the development of traumatic or postoperative adhesions and scarring around nerves. In experimental models, different materials have been studied to limit scar tissue formation when wrapped around nerves. METHODS: A systematic review of studies describing nerve-wrapping materials in a non-transectional rat sciatic nerve model was performed following the PRISMA guidelines. Literature describing nerve-wrapping methods for the prevention of peripheral nerve scarring in rat sciatic nerve models was identified using PubMed and Web of Science, scanned for relevance and analyzed. RESULTS: A total of 15 original articles describing 23 different materials or material combinations for nerve wrapping were included. The heterogeneity of the methods used did not allow a meta-analysis, thus, a systematic review was performed. Out of 28 intervention groups, 21 demonstrated a preventive effect on scar tissue formation in at least one qualitative or quantitative assessment method. CONCLUSIONS: The analyzed literature describes a variety of materials from different origins to limit peripheral nerve scarring and adhesions. Thus, a scar-preventive effect by wrapping peripheral nerves as adhesion prophylaxis seems likely. However, a quantitative comparison of the studies to identify the optimal material or technique is not possible with the diversity of used models and study designs. Therefore, further research needs to be performed to identify the optimal nerve wraps to be used routinely in clinical practice.

Effect of Surgical Release of Entrapped Peripheral Nerves in Sensorimotor Diabetic Neuropathy on Pain and Sensory Dysfunction-Study Protocol of a Prospective, Controlled Clinical Trial.

BACKGROUND: Nerve entrapment has been hypothesized to contribute to the multicausal etiology of axonopathy in sensorimotor diabetic neuropathy. Targeted surgical decompression reduces external strain on the affected nerve and, therefore, may alleviate symptoms, including pain and sensory dysfunction. However, its therapeutic value in this cohort remains unclear. AIM: Quantifying the treatment effect of targeted lower extremity nerve decompression in patients with preexisting painful sensorimotor diabetic neuropathy and nerve entrapment on pain intensity, sensory function, motor function, and neural signal conduction. STUDY DESIGN: This prospective, controlled trial studies 40 patients suffering from bilateral therapy-refractory, painful (n = 20, visual analogue scale, VAS ≥ 5) or painless (n = 20, VAS = 0) sensorimotor diabetic neuropathy with clinical and/or radiologic signs of focal lower extremity nerve compression who underwent unilateral surgical nerve decompression of the common peroneal and the tibial nerve. Tissue biopsies will be analyzed to explore perineural tissue remodeling in correlation with intraoperatively measured nerve compression pressure. Effect size on symptoms including pain intensity, light touch threshold, static and moving two-point discrimination, target muscle force, and nerve conduction velocity will be quantified 3, 6, and 12 months postoperatively, and compared (1) to the preoperative values and (2) to the contralateral lower extremity that continues non-operative management. CLINICAL SIGNIFICANCE: Targeted surgical release may alleviate mechanical strain on entrapped lower extremity nerves and thereby potentially improve pain and sensory dysfunction in a subset of patients suffering from diabetic neuropathy. This trial aims to shed light on these patients that potentially benefit from screening for lower extremity nerve entrapment, as typical symptoms of entrapment might be erroneously attributed to neuropathy only, thereby preventing adequate treatment.

An Algorithm for Elective Amputation Combined with Targeted Muscle Reinnervation in Complex Regional Pain Syndrome-A Perspective.

Complex regional pain syndrome (CRPS) can result in a devastating condition. For a small number of patients, there is a non-response to any existing multimodal therapies and they ultimately request amputation. Such a drastic and final decision is not easy to take for both the patient and the surgeon and requires careful and interdisciplinary assessments and considerations. Furthermore, new surgical procedures, such as targeted muscle reinnervation (TMR) and hybrid prosthetic fitting, and multidisciplinary board advice should be included when considering amputation. In order to help other therapeutic teams in decision making for such rare but more than demanding cases, we aimed to propose an advanced algorithm for amputation indications in CRPS patients combining all these new factors. This algorithm consists of extensive pre-operative psychiatric assessment, diagnostic hybrid prosthetic fitting including fMRI analyses, multidisciplinary board advice as well as targeted muscle reinnervation and amputation procedures with final prosthetic fitting and rehabilitation. By involving multiple disciplines, this algorithm should provide optimized and individualized patient treatment on the one hand and a reliable base for decision making for therapists on the other.

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.

Modern MRI Diagnostics of Upper-Extremity-Related Nerve Injuries-A Prospective Multi-Center Study Protocol for Diagnostics and Follow Up of Peripheral Nerve Injuries.

(1) Background: Peripheral nerve injuries are severe injuries with potentially devastating impairment of extremity function. Correct and early diagnosis as well as regular regeneration observation is of utmost importance for individualized reconstruction and the best possible results. Currently, diagnoses and follow-up examinations are based on clinical examinations supported with electroneurography, which often causes delays in treatment and can result in impaired healing. However, there is currently no diagnostic device that can reliably correlate the anatomic-pathological parameters with the functional-pathological changes initially and during therapy. With new technologies such as MR neurography (MRN), precise visualization of potential nerve damage and visualization of the reinnervation processes is assumed to accelerate clinical decision making and accompaniment of individualized treatment. (2) Methods/Design: This prospective clinical study will examine 60 patients after peripheral nerve lesion aged 18-65 years from trauma timepoint onward. Patients should be observed over a period of 18-24 months with regular clinical examinations, electroneurography, and ultrasound to compare the potential of MRN to current gold-standard diagnostic tools. Furthermore, 20 patients with the same inclusion criteria stated above, with an internal fixation and osteosyntheses of humerus fractures, will be examined to determine the visibility of peripheral nerve structures in close proximity to metal. (3) Discussion: Peripheral nerve injuries are often accompanied with severe, expensive, and long-lasting impairment of extremity function. An early and precise diagnosis of the nerve lesion, as well as the healing course, is crucial to indicate the right therapy as soon as possible to save valuable time for nerve regeneration. Here, new technologies such as MRN aim to visualize nerve injuries on fascicular level, providing not only early diagnosis and therapy decisions, but also providing a precise tool for monitoring of reinnervation processes. As severe injuries of a nerve are often accompanied with bone fractures and internal fixation, we also aim to evaluate the visualization feasibility of nerves in close proximity to metal, and ultimately improve the outcome and extremity function of patients after a peripheral nerve injury.