Nerve trauma of the lower extremity: evaluation of 60,422 leg injured patients from the TraumaRegister DGU® between 2002 and 2015

Electrical stimulation enhances sciatic nerve regeneration using a silk-based conductive scaffold beyond traditional nerve guide conduits

Despite recent advancements in peripheral nerve regeneration, the creation of nerve conduits with chemical and physical cues to enhance glial cell function and support axonal growth remains challenging. This study aimed to assess the impact of electrical stimulation (ES) using a conductive nerve conduit on sciatic nerve regeneration in a rat model with transection injury. The study involved the fabrication of conductive nerve conduits using silk fibroin and Au nanoparticles (AuNPs). Collagen hydrogel loaded with green fluorescent protein (GFP)-positive adipose-derived mesenchymal stem cells (ADSCs) served as the filling for the conduit. Both conductive and non-conductive conduits were applied with and without ES in rat models. Locomotor recovery was assessed using walking track analysis. Histological evaluations were performed using H&E, luxol fast blue staining and immunohistochemistry. Moreover, TEM analysis was conducted to distinguish various ultrastructural aspects of sciatic tissue. In the ES + conductive conduit group, higher S100 (p < 0.0001) and neurofilament (p < 0.001) expression was seen after 6 weeks. Ultrastructural evaluations showed that conductive scaffolds with ES minimized Wallerian degeneration. Furthermore, the conductive conduit with ES group demonstrated significantly increased myelin sheet thickness and decreased G. ratio compared to the autograft. Immunofluorescent images confirmed the presence of GFP-positive ADSCs by the 6th week. Locomotor recovery assessments revealed improved function in the conductive conduit with ES group compared to the control group and groups without ES. These results show that a Silk/AuNPs conduit filled with ADSC-seeded collagen hydrogel can function as a nerve conduit, aiding in the restoration of substantial gaps in the sciatic nerve with ES. Histological and locomotor evaluations indicated that ES had a greater impact on functional recovery compared to using a conductive conduit alone, although the use of conductive conduits did enhance the effects of ES.

[Frequency of Chronic Pain after Work-Related Trauma: A Preliminary Status Survey during Workers' Compensation Rehabilitation in a Tertiary Clinic]

BACKGROUND

Chronic pain after trauma and surgery is a long-term complication. Its relevance for patients within the workers' compensation rehabilitation process has not been adequately investigated.

OBJECTIVES

Initial evaluation of frequency of chronic pain after occupational accidents.

METHODS

In 2017, surgical inpatients (18-65 y) treated in a tertiary hospital were asked about chronic pain arising from an occupational trauma recognized by statutory occupation insurance (interval 2.8±6.9 years), regardless of care received, first at the time of hospitalization and then by telephone interview 6 months later. The focus was on patients with a work-related trauma (A) within the past month or (B) >6 months.

PRIMARY OUTCOME

frequency of work trauma-related chronic pain (>6 months) at the initial interview (point prevalence), secondary outcomes: frequency of chronicity at 6 months (A) and persistence of chronic pain (B). Tertiary outcomes: ability to work, occupational injury classification, burden based on pain intensity, localization, and medication, functional deficits due to the existence of chronic pain, and comorbidity.

RESULTS

Out of 415 patients included in the survey, 85% (160/188) reported accident-related chronic pain (predominantly moderate to highly severe in intensity, localized at joints and bones). 90% (131/145) also reported this pain six months later. 67% (64/96) reported chronic pain for the first time. Patients with chronic pain at follow-up (281/369) were less likely to return to work (p=0.003), required analgesics in 60%, were more often comorbid (p<0.002) and had greater functional deficits (p<0.002).

CONCLUSION

Despite the preliminary nature of the data, chronic pain seems to be common after occupational trauma and negatively affects the recovery of work ability in the long term. Based on the present observational data, a further differentiated re-evaluation of prospective data considering therapeutic measures is strongly recommended.

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

Evaluating the Efficacy of a Thermoresponsive Hydrogel for Delivering Anti-Collagen Antibodies to Reduce Posttraumatic Scarring in Orthopedic Tissues

Excessive posttraumatic scarring in orthopedic tissues, such as joint capsules, ligaments, tendons, muscles, and peripheral nerves, presents a significant medical problem, resulting in pain, restricted joint mobility, and impaired musculoskeletal function. Current treatments for excessive scarring are often ineffective and require the surgical removal of fibrotic tissue, which can aggravate the problem. The primary component of orthopedic scars is collagen I-rich fibrils. Our research team has developed a monoclonal anti-collagen antibody (ACA) that alleviates posttraumatic scarring by inhibiting collagen fibril formation. We previously established the safety and efficacy of ACA in a rabbit-based arthrofibrosis model. In this study, we evaluate the utility of a well-characterized thermoresponsive hydrogel (THG) as a delivery vehicle for ACA to injury sites. Crucial components of the hydrogel included N-isopropylacrylamide, poly(ethylene glycol) diacrylate, and hyaluronic acid. Our investigation focused on in vitro ACA release kinetics, stability, and activity. Additionally, we examined the antigen-binding characteristics of ACA post-release from the THG in an in vivo context. Our preliminary findings suggest that the THG construct exhibits promise as a delivery platform for antibody-based therapeutics to reduce excessive scarring in orthopedic tissues.

Evaluation of combined effects of brief electrical stimulation and Schwann-like cells on sciatic nerve injury model

Severe nerve injuries can be treated with electrical stimulation and stem cell therapies, but little is known about the potential benefits of combining these two treatments. In an effort to investigate this combination, we conducted a study to evaluate the effectiveness of electrical stimulation and Schwann-like cell transplantation in female Wistar albino rats. Our study consisted of five groups of rats: a sham group, an injury group, an electrical stimulation group, a Schwann-like cell group, and a combination group. The experimental groups received electrical stimulation, Schwann-like cell transplantation, or both. The animals sciatic function index was evaluated during a 6-week recovery period, and nerve conduction velocity, wet muscle mass, and nerve tissues were also analyzed. The results of the study showed that all experimental groups had a faster functional recovery compared to the injury group, although the difference between groups was not statistically significant. Both the combination group and the Schwann-like cell transplantation group had a higher nerve conduction velocity compared to the other experimental groups. However, there was no significant difference between the combination and Schwann-like cell transplantation groups. Nonetheless, histological analysis showed a better axonal reorganization in the combination group. The study provides preliminary evidence of the potential benefits of combining electrical stimulation and Schwann-like cell transplantation in treating severe nerve injuries. However, further studies with larger sample sizes are needed to confirm these findings and optimize the treatment parameters.

Evaluation of Processed Nerve Allograft in Peripheral Nerve Surgery: A Systematic Review and Critical Appraisal

Peripheral nerve injuries cause substantial problems when not treated properly. A specific problem is reconstruction of nerve defects, which can be treated in different ways. This study aimed to systematically review whether processed nerve allograft (PNA) is justified in reconstruction of a nerve defect in patients after posttraumatic or iatrogenic peripheral nerve injury and to compare PNA with other established methods.

Methods

A systematic review with a focused question, PICO (patient, intervention, comparison, outcome) and constraints, was performed. A structured literature search, including several databases, was done to evaluate the existing evidence for outcomes and postoperative complications related to PNA. The certainty of evidence was classified according to Grading of Recommendations, Assessment, Development and Evaluations.

Results

No conclusions, concerning differences in outcome of nerve reconstruction using PNA compared with the use of nerve autograft or conduits, could be drawn. The level of certainty for all evaluated outcomes was very low (⊕◯◯◯). Most published studies lack a control group to patients treated with PNA; being only descriptive, making it difficult to compare PNA with established methods without substantial risk of bias. For studies including a control group, the scientific evidence was of very low certainty, due to a low number of included patients, and large, undefined loss of patients during follow-up, rendering a high risk of bias. Finally, the authors often had financial disclosures.

Conclusion

Properly conducted randomized controlled trial studies on the use of PNA in reconstruction of peripheral nerve injuries are needed to establish recommendations in clinical practice.

Procedure Costs of Peripheral Nerve Graft Reconstruction

Peripheral nerve injuries not repaired in an effective and timely manner may lead to permanent functional loss and/or pain. For gaps greater than 5 mm, autograft has been the gold standard. Allograft has recently emerged as an attractive alternative, delivering comparable functional recovery without risk of second surgical site morbidities. Cost is an important factor when considering surgical options, and with a paucity of nerve repair cost data, this study aimed to compare allograft and autograft procedure costs.

Methods

A retrospective cross-sectional observational study using the US all-payer PINC AI Healthcare Database examined facility procedure costs and cost drivers in patients undergoing allograft or autograft repair of an isolated single peripheral nerve injury between January 2018 and August 2020. Inpatient repairs were limited to nerve-specific DRGs. Multivariable regression evaluated risk-adjusted procedure cost differences.

Results

Peripheral nerve graft repairs (n = 1363) were more frequent in the outpatient setting, and more than half involved the use of allograft nerve. Procedure costs for allograft and autograft repair were not significantly different in the outpatient (P = 0.43) or inpatient (P = 0.71) setting even after controlling for other risk factors. Operating room cost was significantly higher for autograft in outpatient (P < 0.0001) but not inpatient (P = 0.46), whereas allograft implant cost was significantly higher in both settings (P < 0.0001).

Conclusions

No significant differences in procedure costs for autograft and allograft repair in inpatient and outpatient settings were found using real-world data. Future research should explore longer-term costs.

Does Electrical Stimulation through Nerve Conduits Improve Peripheral Nerve Regeneration?—A Systematic Review

Background: Peripheral nerve injuries affect over 2% of trauma patients and can lead to severe functional impairment and permanent disability. Autologous nerve transplantation is still the gold standard in the reconstruction of nerve defects. For small defects, conduits can be considered for bridging. Lately, the combined use of conduits and electrical stimulation has gained attention in the treatment of peripheral nerve injury. This review aimed to present the currently available data on this topic. Methods: PubMed, Embase, Medline and the Cochrane Library were searched for studies on electrical stimulation through nerve conduits for nerve defects in in vivo studies. Results: Fifteen studies fit the inclusion criteria. All of them reported on the application of nerve conduits combined with stimulation for sciatic nerve gaps in rats. Functional, electrophysiological and histological evaluations showed improved nerve regeneration after electrical stimulation. High variation was observed in the treatment protocols. Conclusion: Electrically stimulated conduits could improve peripheral nerve regeneration in rat models. The combined application of nerve guidance conduits and electrical stimulation shows promising results and should be further evaluated under standardized conditions.

An Epidemiological and Etiological Analysis of 5026 Peripheral Nerve Lesions from a European Level I Trauma Center

Background: Peripheral nerve lesions are associated with debilitating long-term consequences. Albeit being essential for evidence-based clinical decision making, epidemiological and etiological data are scarce. We therefore aimed to comprehensively analyze epidemiological and etiological factors of peripheral nerve lesions in one of the largest cohorts. Methods: We screened a total of 110,667 patients treated at our level I trauma center between January 2012 and July 2020 for nerve lesions. Subsequently, demographics, etiologies, concomitant injuries, and lesion characteristics were analyzed. Results: A total of 5026 patients, predominantly young males suffering from non-work-related nerve injuries, were treated. Proximal levels of injury were more likely to be accompanied by fractures, whereas more distal injuries with concomitant vessel or tendon injury. Main causes were 54.6% lacerations. Acute traumatic nerve injury was treated within 24 h in 55.9% of cases. Conclusions: Given the young age of affected patients, early diagnosis and treatment in specialized centers may facilitate their early return to work and improve long-term functional outcomes. The data show the importance of a special attention on nerve injuries, which may be masked by large accompanying injuries. New findings on lesion characteristics of selected subgroups and accompanying circumstances can support a change in treatment strategies.

ESWT Diminishes Axonal Regeneration following Repair of the Rat Median Nerve with Muscle-In-Vein Conduits but Not after Autologous Nerve Grafting

Investigations reporting positive effects of extracorporeal shockwave therapy (ESWT) on nerve regeneration are limited to the rat sciatic nerve model. The effects of ESWT on muscle-in-vein conduits (MVCs) have also not been investigated yet. This study aimed to evaluate the effects of ESWT after repair of the rat median nerve with either autografts (ANGs) or MVCs. In male Lewis rats, a 7 mm segment of the right median nerve was reconstructed either with an ANG or an MVC. For each reconstructive technique, one group of animals received one application of ESWT while the other rats served as controls. The animals were observed for 12 weeks, and nerve regeneration was assessed using computerized gait analysis, the grasping test, electrophysiological evaluations and histological quantification of axons, blood vessels and lymphatic vasculature. Here, we provide for the first time a comprehensive analysis of ESWT effects on nerve regeneration in a rat model of median nerve injury. Furthermore, this study is among the first reporting the quantification of lymphatic vessels following peripheral nerve injury and reconstruction in vivo. While we found no significant direct positive effects of ESWT on peripheral nerve regeneration, results following nerve repair with MVCs were significantly inferior to those after ANG repair.

Biological Approach in the Treatment of External Popliteal Sciatic Nerve (Epsn) Neurological Injury: Review

The external popliteal sciatic nerve (EPSN) is the nerve of the lower extremity most frequently affected by compressive etiology. Its superficial and sinuous anatomical course is closely related to other rigid anatomical structures and has an important dynamic neural component. Therefore, this circumstance means that this nerve is exposed to multiple causes of compressive etiology. Despite this fact, there are few publications with extensive case studies dealing with treatment. In this review, we propose to carry out a narrative review of the neuropathy of the EPSN, including an anatomical reminder, its clinical presentation and diagnosis, as well as its surgical and biological approach. The most novel aspect we propose is the review of the possible role of biological factors in the reversal of this situation.

Role of Electrical Stimulation in Peripheral Nerve Regeneration: A Systematic Review

Functional recovery after peripheral nerve injury is often suboptimal despite the intrinsic permissive growth environment of the peripheral nervous system. The objective of this systematic review is to explore the use of electrical stimulation (ES) for peripheral nerve regeneration.

BET protein inhibition in macrophages enhances dorsal root ganglion neurite outgrowth in female mice

Peripheral nerve regeneration is limited after injury, especially in humans, due to the large distance the axons have to grow in the limbs. This process is highly dependent on the expression of neuroinflammatory factors produced by macrophages and glial cells. Given the importance of the epigenetic BET proteins on inflammation, we aimed to ascertain if BET inhibition may have an effect on axonal outgrowth. For this purpose, we treated female mice with JQ1 or vehicle after sciatic nerve crush injury and analyzed target reinnervation. We also used dorsal root ganglion (DRG) culture explants to analyze the effects of direct BET inhibition or treatment with conditioned medium from BET-inhibited macrophages. We observed that although JQ1 produced an enhancement of IL-4, IL-13, and GAP43 expression, it did not have an effect on sensory or motor reinnervation after crush injury in vivo. In contrast, JQ1 reduced neurite growth when interacting directly with DRG neurons ex vivo, whereas conditioned medium from JQ1-treated macrophages promoted neurite outgrowth. Therefore, BET-inhibited macrophages secrete pro-regenerative factors that induce neurite outgrowth, and that may counteract the direct inhibition of BET proteins in neurons in vivo. Finally, we observed an activation of the STAT6 pathway in DRG explants treated with conditioned medium from JQ1-treated macrophages. In conclusion, this study demonstrates that BET protein inhibition in macrophages provides a mechanism to enhance axonal outgrowth. However, specific targeting of BET proteins to macrophages will be needed to efficiently enhance functional recovery after nerve injury.

Delayed Presentation of Sciatic Nerve Injury with Gap: A Case Report with a Unique Solution from the Past

CASE

A 35-year-old farmer presented with a foot ulcer on his left flail foot because of a sciatic nerve injury of 1-year duration. A gap of 11 cm was observed in the sciatic nerve for which he underwent 2-staged pedicled peroneal nerve grafting and posterior bone block procedure for the ankle. He had S3 grade sensation at 5-year follow-up without any recurrence of ulcer and a stable foot without external support for walking.

CONCLUSION

Staged pedicled peroneal nerve grafting with a posterior bone block procedure is a viable solution for very large sciatic nerve defect with predictable results.

Outcomes of Tibial Nerve Repair and Transfer: A Structured Evidence-Based Systematic Review and Meta-Analysis

Although nerve transfer and repair are well-established for treatment of nerve injury in the upper extremity, there are no established parameters for when or which treatment modalities to utilize for tibial nerve injuries. The objective of our study is to conduct a systematic review of the effectiveness of end-to-end repair, neurolysis, nerve grafting, and nerve transfer in improving motor function after tibial nerve injury. PubMed, Cochrane, Medline, and Embase libraries were queried according to the PRISMA guidelines for articles that present functional outcomes after tibial nerve injury in humans treated with nerve transfer or repair. The final selection included Nineteen studies with 677 patients treated with neurolysis (373), grafting (178), end-to-end repair (90), and nerve transfer (30), from 1985 to 2018. The mean age of all patients was 27.0 ± 10.8 years, with a mean preoperative interval of 7.4 ± 10.5 months, and follow-up period of 82.9 ± 25.4 months. The mean graft repair length for nerve transfer and grafting patients was 10.0 ± 5.8 cm, and the most common donor nerve was the sural nerve. The most common mechanism of injury was gunshot wound, and the mean MRC of all patients was 3.7 ± 0.6. Good outcomes were defined as MRC ≥ 3. End-to-end repair treatment had the greatest number of good outcomes, followed by neurolysis. Patients with preoperative intervals less than 7 months were more likely to have good outcomes than those greater than 7 months. Patients with sport injuries had the highest percentage of good outcomes in contrast to patients with transections and who were in MVAs. We found no statistically significant difference in good outcomes between the use of sural and peroneal donor nerve grafts, nor between age, graft length, and MRC score.

Beyond the Knife-Reviewing the Interplay of Psychosocial Factors and Peripheral Nerve Lesions

Peripheral nerve injuries are a common clinical problem. They not only affect the physical capabilities of the injured person due to loss of motor or sensory function but also have a significant impact on psychosocial aspects of life. The aim of this work is to review the interplay of psychosocial factors and peripheral nerve lesions. By reviewing the published literature, we identified several factors to be heavily influenced by peripheral nerve lesions. In addition to psychological factors like pain, depression, catastrophizing and stress, social factors like employment status and worker's compensation status could be identified to be influenced by peripheral nerve lesions as well as serving as predictors of functional outcome themselves, respectively. This work sheds a light not only on the impact of peripheral nerve lesions on psychosocial aspects of life, but also on the prognostic values of these factors of functional outcome. Interdisciplinary, individualized treatment of patients is required to identify patient at risk for adverse outcomes and provide them with emotional support when adapting to their new life situation.

Efficacy of low-level laser therapy in nerve injury repair-a new era in therapeutic agents and regenerative treatments

BACKGROUND

Traumatic nerve injuries may result in severe motor dysfunctions. Although the microenvironment of peripheral axons favors their regeneration, regenerative process is not always successful.

PURPOSE

We reviewed and discussed the main findings obtained with low-level laser therapy (LLLT), a therapeutic intervention that has been employed in order to achieve an optimized regeneration process in peripheral axons.

SCOPE

Disseminating the best available evidence for the effectiveness of this therapeutic strategy can potentially improve the statistics of success in the clinical treatment of nerve injuries. We found evidence that LLLT optimizes the regeneration of peripheral axons, improving motor function, especially in animal models. Nonetheless, further clinical evidence is still needed before LLLT can be strongly recommended. Although the results are promising, the elucidation of the mechanisms of action and safety assessment are necessary to support highquality clinical studies.

CONCLUSION

The present careful compilation of findings with consistent pro-regenerative evidence and published in respected scientific journals can be valuable for health professionals and researchers in the field, possibly contributing to achieve more promising results in future randomized controlled trials and interventions, providing better prognosis for clinical practice.

[Functional reconstruction in traumatic paralysis]

BACKGROUND

Traumatic nerve injuries are associated with a high morbidity and long rehabilitation times. The extent of a nerve lesion and the related regeneration potential can often only be estimated during the course, whereby the time window for successful surgical interventions is limited.

OBJECTIVE

The incidence and distribution of traumatic nerve lesions are reported. Algorithms for treatment decisions are presented.

MATERIAL AND METHODS

Statistics from the German TraumaRegister DGU® as well as international registers were evaluated. The results of basic research and expert recommendations for diagnostics and treatment are discussed.

RESULTS AND CONCLUSION

A strategic approach to conservative and surgical treatment of traumatic nerve injuries depending on the extent of injury and resulting regeneration potential is recommended. In conjunction with the clinical course, electrophysiology and imaging diagnostics, e.g. nerve sonography, can help to differentiate between neurapraxia, axonotmesis and neurotmesis.

Preclinical study of peripheral nerve regeneration using nerve guidance conduits based on polyhydroxyalkanaotes

Nerve guidance conduits (NGCs) are used as an alternative to the "gold standard" nerve autografting, preventing the need for surgical intervention required to harvest autologous nerves. However, the regeneration outcomes achieved with the current NGCs are only comparable with autografting when the gap is short (less than 10 mm). In the present study, we have developed NGCs made from a blend of polyhydroxyalkanoates, a family of natural resorbable polymers. Hollow NGCs made from a 75:25 poly(3-hydroxyoctanoate)/poly(3-hydroxybutyrate) blend (PHA-NGCs) were manufactured using dip-molding. These PHA-NGCs showed appropriate flexibility for peripheral nerve regeneration. In vitro cell studies performed using RT4-D6P2T rat Schwann cell line confirmed that the material is capable of sustaining cell proliferation and adhesion. PHA-NGCs were then implanted in vivo to repair 10 mm gaps of the median nerve of female Wistar rats for 12 weeks. Functional evaluation of the regenerated nerve using the grasping test showed that PHA-NGCs displayed similar motor recovery as the autograft, starting from week 7. Additionally, nerve cross-sectional area, density and number of myelinated cells, as well as axon diameter, fiber diameter, myelin thickness and g-ratio obtained using the PHA-NGCs were found comparable to an autograft. This preclinical data confirmed that the PHA-NGCs are indeed highly promising candidates for peripheral nerve regeneration.

The Role of Dietary Nutrients in Peripheral Nerve Regeneration

Peripheral nerves are highly susceptible to injuries induced from everyday activities such as falling or work and sport accidents as well as more severe incidents such as car and motorcycle accidents. Many efforts have been made to improve nerve regeneration, but a satisfactory outcome is still unachieved, highlighting the need for easy to apply supportive strategies for stimulating nerve growth and functional recovery. Recent focus has been made on the effect of the consumed diet and its relation to healthy and well-functioning body systems. Normally, a balanced, healthy daily diet should provide our body with all the needed nutritional elements for maintaining correct function. The health of the central and peripheral nervous system is largely dependent on balanced nutrients supply. While already addressed in many reviews with different focus, we comprehensively review here the possible role of different nutrients in maintaining a healthy peripheral nervous system and their possible role in supporting the process of peripheral nerve regeneration. In fact, many dietary supplements have already demonstrated an important role in peripheral nerve development and regeneration; thus, a tailored dietary plan supplied to a patient following nerve injury could play a non-negotiable role in accelerating and promoting the process of nerve regeneration.

A guide to reducing adverse outcomes in rabbit models of sciatic nerve injury

Background

Peripheral nerve damage can have debilitating consequences. Rabbit sciatic nerve transection models allow the effective evaluation of surgical repair strategies for large nerve gaps. Despite advantages in size, ease of handling, and functional utility, rabbits can suffer from a number of side effects that affect animal welfare and the quality of scientific inquiry. Such side-effects, which include pressure ulcers and traumatic damage to the foot, are primarily a consequence of insensitivity of the distal hindlimb following sciatic nerve injury. In this study, we present a number of methodologies for identifying, treating, and preventing unintended adverse effects in rabbit sciatic nerve injury models.

Results

First, we categorize pressure ulcers according to their severity and describe the deployment of a padded bandaging technique to enable ulcer healing. We also introduce a proactive bandaging approach to reduce the likelihood of pressure ulcer formation. Second, we define phenotypes that distinguish between foot injuries resulting from self-mutilation (autotomy) from those caused by incidental traumatic injury secondary to sensori-motor damage. Finally, we detail an effective strategy to reduce the usage of Elizabethan collars; through a gradual weaning protocol, their usefulness in preventing autotomy is retained, while their propensity to impede rabbit grooming and cause abrasion-injury to the neck region is minimized.

Conclusions

We suggest that application of these methods offer a practical and systematic approach to avoid adverse side effects associated with rabbit sciatic nerve damage, enabling improved animal welfare and scientific outcomes in a powerful nerve injury model.

Integrated analysis of long noncoding RNAs and mRNA expression profiles reveals the potential role of lncRNAs in early stage of post-peripheral nerve injury in Sprague-Dawley rats

The regulatory role of lncRNAs in the early stage post peripheral nerve injury (PNI) is not yet clear. In this study, next-generation sequencing was used to perform deep sequencing on normal sciatic nerves (control) and lesional tissues derived on the 4th (D4) and 7th days (D7) after sciatic nerve injury in rats. Time-point unique differentially expressed lncRNAs (DElncRNAs) were analyzed for functional enrichment. The results showed that 776 DElncRNAs were unique to D4, and their functions were mainly enriched in wound healing, phosphatase binding and MAPK signaling pathways; 317 DElncRNAs were unique to D7, and their functions were mainly enriched in ion transmembrane transporter channel activity; 579 DElncRNAs were shared by these two days, and their functions were mainly enriched in axongenesis, the PI3K-Akt signaling pathway and cell cycle. Furthermore, lncRNA-mRNA interaction networks were constructed in functions or pathways with a high enrichment rate. Finally, 3 mRNAs and 4 lncRNAs in the axongenesis interaction network were selected, and their expression levels were verified by RT-qPCR. This study preliminarily revealed the regulatory role of lncRNAs at different time points in the early stage post PNI, which provides potential targets for basic research and clinical treatment of PNI.

Sonographic Evaluation of Peripheral Sciatic Nerve Injury: A Case Study

Traumatic peripheral nerve injury is not a common finding in the general population but is increasingly being recognized and diagnosed in trauma and emergency medicine settings. Peripheral nerve injury can cause temporary or long-term motor and sensory loss, as well as intense pain and disability, if left untreated. The cause of peripheral nerve injury is diverse and often involves soft tissue damage, fractures, and hemorrhage in cases of traumatic injury. Peripheral nerve injury does not always heal spontaneously and, depending on severity, may warrant surgical intervention and repair. Although electrodiagnosic testing and surgical exploration are considered gold standards for peripheral nerve injury, high-resolution sonographic examination supplemented by clinical findings may be of value. The use of sonography demonstrated utility in determining a strategic management timeline and the efficacy of a surgical intervention.

Chronic pain with neuropathic characteristics after surgery for major trauma to the lower limb: prevalence, predictors, and association with pain severity, disability, and quality of life in the UK WHiST trial

AIMS

To identify the prevalence of neuropathic pain after lower limb fracture surgery, assess associations with pain severity, quality of life and disability, and determine baseline predictors of chronic neuropathic pain at three and at six months post-injury.

METHODS

Secondary analysis of a UK multicentre randomized controlled trial (Wound Healing in Surgery for Trauma; WHiST) dataset including adults aged 16 years or over following surgery for lower limb major trauma. The trial recruited 1,547 participants from 24 trauma centres. Neuropathic pain was measured at three and six months using the Doleur Neuropathique Questionnaire (DN4); 701 participants provided a DN4 score at three months and 781 at six months. Overall, 933 participants provided DN4 for at least one time point. Physical disability (Disability Rating Index (DRI) 0 to 100) and health-related quality-of-life (EuroQol five-dimension five-level; EQ-5D-5L) were measured. Candidate predictors of neuropathic pain included sex, age, BMI, injury mechanism, concurrent injury, diabetes, smoking, alcohol, analgaesia use pre-injury, index surgery location, fixation type, Injury Severity Score, open injury, and wound care.

RESULTS

The median age of the participants was 51 years (interquartile range 35 to 64). At three and six months post-injury respectively, 32% (222/702) and 30% (234/787) had neuropathic pain, 56% (396/702) and 53% (413/787) had chronic pain without neuropathic characteristics, and the remainder were pain-free. Pain severity was higher among those with neuropathic pain. Linear regression analyses found that those with neuropathic pain at six months post-injury had more physical disability (DRI adjusted mean difference 11.49 (95% confidence interval (CI) 7.84 to 15.14; p < 0.001) and poorer quality of life (EQ-5D utility -0.15 (95% CI -0.19 to -0.11); p < 0.001) compared to those without neuropathic characteristics. Logistic regression identified that prognostic factors of younger age, current smoker, below knee fracture, concurrent injuries, and regular analgaesia pre-injury were associated with higher odds of post-injury neuropathic pain.

CONCLUSION

Pain with neuropathic characteristics is common after lower limb fracture surgery and persists to six months post-injury. Persistent neuropathic pain is associated with substantially poorer recovery. Further attention to identify neuropathic pain post-lower limb injury, predicting patients at risk, and targeting interventions, is indicated. Cite this article: Bone Joint J 2021;103-B(6):1047-1054.

The Role of the IL-4 Signaling Pathway in Traumatic Nerve Injuries

Following traumatic peripheral nerve injury, adequate restoration of function remains an elusive clinical goal. Recent research highlights the complex role that the immune system plays in both nerve injury and regeneration. Pro-regenerative processes in wounded soft tissues appear to be significantly mediated by cytokines of the type 2 immune response, notably interleukin (IL)-4. While IL-4 signaling has been firmly established as a critical element in general tissue regeneration during wound healing, it has also emerged as a critical process in nerve injury and regeneration. In this context of peripheral nerve injury, endogenous IL-4 signaling has recently been confirmed to influence more than leukocytes, but including also neurons, axons, and Schwann cells. Given the role IL-4 plays in nerve injury and regeneration, exogenous IL-4 and/or compounds targeting this signaling pathway have shown encouraging preliminary results to treat nerve injury or other neuropathy in rodent models. In particular, the exogenous stimulation of the IL-4 signaling pathway appears to promote postinjury neuron survival, axonal regeneration, remyelination, and thereby improved functional recovery. These preclinical data strongly suggest that targeting IL-4 signaling pathways is a promising translational therapy to augment treatment approaches of traumatic nerve injury. However, a better understanding of the type 2 immune response and associated signaling networks functioning within the nerve injury microenvironment is still needed to fully develop this promising therapeutic avenue.

Evaluation and Treatment of Foot Drop Using Nerve Transfer Techniques

Foot drop represents a complex pathologic condition, requiring a multidisciplinary approach for appropriate evaluation and treatment. Multiple etiologic factors require recognition before considering invasive/operative intervention. When considering surgical management for the treatment of foot drop, it is first and foremost imperative to establish the cause of the condition. Not all causes resulting in clinical foot drop have surgical options. Establishing a cause allows the provider to more appropriately curtail a multidisciplinary approach to working-up, and ultimately, treating the patient. The authors offer an algorithm for evaluating and treating foot drop conditions associated with lumbar spine radiculopathy and peripheral nerve lesions.

Nerve Ultrasound in Traumatic and Iatrogenic Peripheral Nerve Injury

Peripheral nerve injury is a potentially debilitating disorder that occurs in an estimated 2–3% of all patients with major trauma, in a similar percentage of medical procedures. The workup of these injuries has traditionally been clinical, combined with electrodiagnostic testing. However, this has limitations, especially in the acute phase of the trauma or lack of any recovery, when it is very important to determine nerve continuity and perform surgical exploration and repair in the case of the complete transection or intraneural fibrosis. Ultrasound can help in those situations. It is a versatile imaging technique with a high sensitivity of 93% for detecting focal nerve lesions. Ultrasound can assess the structural integrity of the nerve, neuroma formation and other surrounding abnormalities of bone or foreign bodies impeding the nerve. In addition, this can help to prevent iatrogenic nerve injury by marking the nerve before the procedure. This narrative review gives an overview of why and how nerve ultrasound can play a role in the detection, management and prevention of peripheral nerve injury.

Sensory profiles and immune-related expression patterns of patients with and without neuropathic pain after peripheral nerve lesion

In this multicenter cross-sectional study, we determined sensory profiles of patients with (NL-1) and without neuropathic pain (NL-0) after nerve lesion and assessed immune-related systemic gene expression. Patients and matched healthy controls filled in questionnaires and underwent neurological examination, neurophysiological studies, quantitative sensory testing, and blood withdrawal. Neuropathic pain was present in 67/95 (71%) patients (NL-1). Tactile hyperalgesia was the most prominent clinical sign in NL-1 patients (P < 0.05). Questionnaires showed an association between neuropathic pain and the presence of depression, anxiety, and catastrophizing (P < 0.05 to P < 0.01). Neuropathic pain was frequently accompanied by other chronic pain (P < 0.05). Quantitative sensory testing showed ipsilateral signs of small and large fiber impairment compared to the respective contralateral side, with elevated thermal and mechanical detection thresholds (P < 0.001 to P < 0.05) and lowered pressure pain threshold (P < 0.05). Also, more loss of function was found in patients with NL-1 compared to NL-0. Pain intensity was associated with mechanical hyperalgesia (P < 0.05 to P < 0.01). However, quantitative sensory testing did not detect or predict neuropathic pain. Gene expression of peptidylglycine α-amidating monooxygenase was higher in NL patients compared with healthy controls (NL-1, P < 0.01; NL-0, P < 0.001). Also, gene expression of tumor necrosis factor-α was higher in NL-1 patients compared with NL-0 (P < 0.05), and interleukin-1ß was higher, but IL-10 was lower in NL-1 patients compared with healthy controls (P < 0.05 each). Our study reveals that nerve lesion presents with small and large nerve fiber dysfunction, which may contribute to the presence and intensity of neuropathic pain and which is associated with a systemic proinflammatory pattern.

Electrical stimulation to enhance peripheral nerve regeneration: Update in molecular investigations and clinical translation

Peripheral nerve injuries are common and frequently result in incomplete functional recovery even with optimal surgical treatment. Permanent motor and sensory deficits are associated with significant patient morbidity and socioeconomic burden. Despite substantial research efforts to enhance peripheral nerve regeneration, few effective and clinically feasible treatment options have been found. One promising strategy is the use of low frequency electrical stimulation delivered perioperatively to an injured nerve at the time of surgical repair. Possibly through its effect of increasing intraneuronal cyclic AMP, perioperative electrical stimulation accelerates axon outgrowth, remyelination of regenerating axons, and reinnervation of end organs, even with delayed surgical intervention. Building on decades of experimental evidence in animal models, several recent, prospective, randomized clinical trials have affirmed electrical stimulation as a clinically translatable technique to enhance functional recovery in patients with peripheral nerve injuries requiring surgical treatment. This paper provides an updated review of the cellular physiology of electrical stimulation and its effects on axon regeneration, Level I evidence from recent prospective randomized clinical trials of electrical stimulation, and ongoing and future directions of research into electrical stimulation as a clinically feasible adjunct to surgical intervention in the treatment of patients with peripheral nerve injuries.

The Interdisciplinary Management of Foot Drop

BACKGROUND

Foot drop can be caused by a variety of diseases and injuries. Although it is a common condition, its overall incidence has not been reported to date. Foot drop markedly restricts the everyday activities of persons suffering from it. There is, therefore, a need for an optimized strategy for its diagnosis and treatment that would be standardized across the medical specialties encountering patients with this problem.

METHODS

This article consists of a review on the basis of pertinent publications re- trieved by a search in the Pubmed/MEDLINE and Cochrane databases, as well as a description of the authors' proposed strategy for the diagnosis and treatment of foot drop.

RESULTS

Foot drop can be due to a disturbance at any central or peripheral location along the motor neural pathway that terminates in the dorsiflexor muscles of the foot, or at multiple locations in series. Optimal localization of the lesion(s) is a pre- requisite for appropriate treatment and a successful outcome. The most common causes are L5 radiculopathy and peroneal nerve injury. An operation by a neuro- surgeon or spinal surgeon is a reasonable option whenever there is a realistic chance that the nerve will recover. In our opinion, any patient with a subjectively disturbing foot drop and a clinically suspected compressive neuropathy of the peroneal nerve should be informed about the option of surgical decompression of the nerve at the fibular head, which can be performed with little risk. In case of a permanent foot drop, some patients can benefit from muscle-transfer surgery. For spastic foot drop, the option of botulinum toxin injections should be evaluated.

CONCLUSION

The care of patients with foot drop could be optimized by interdisciplin- ary foot-drop clinics involving all of the relevant specialists. The goals of treatment should always be improved mobility in everyday life and the prevention of falls, pain, and abnormal postures.

Enhancement of sciatic nerve regeneration with dual delivery of vascular endothelial growth factor and nerve growth factor genes

BACKGROUND

Peripheral nerve injury is one common clinical disease worldwide, in which sciatic nerve is anatomically the most challenging to regenerate given its length and large cross-sectional area. For the present, autologous nerve grafting remains to be the most ideal strategy when treating with sciatic nerve injury. However, this method sacrifices healthy nerves and requires highly intensive surgery, still calling for other advanced alternatives for nerve grafting.

RESULTS

In this study, we utilized previously well-established gene delivery system to dually deliver plasmid DNA (pDNA) encoding vascular endothelial growth factor (VEGF) and nerve growth factor (NGF), exploring therapeutics for sciatic nerve injury. Low-molecular-weight branched polyethylenimine (bPEI) was constructed as the backbone structure of gene vectors, and it was further crosslinked to synthesize degradable polycations via the conjugation of dialdehydes. Potential synergistic effect between VEGF and NGF proteins were observed on rat sciatic nerve crush injury model in this study.

CONCLUSIONS

We concluded that dual delivery of plasmid VEGF and NGF as gene therapy could enhance sciatic nerve regeneration.

Animal models used to study direct peripheral nerve repair: a systematic review

Objective:

Peripheral nerve repair is required after traumatic injury. This common condition represents a major public health problem worldwide. Recovery after nerve repair depends on several factors, including the severity of the injury, the nerve involved, and the surgeon’s technical skills. Despite the precise microsurgical repair of nerve lesions, adequate functional recovery is not always achieved and, therefore, the regeneration process and surgical techniques are still being studied. Pre-clinical animal models are essential for this research and, for this reason, the focus of the present systematic review (according to the PRISMA statement) was to analyze the different animal models used in pre-clinical peripheral nerve repair studies.

Data sources:

Original articles, published in English from 2000 to 2018, were collected using the Web of Science, Scopus, and PubMed databases.

Data selection:

Only preclinical trials on direct nerve repair were included in this review. The articles were evaluated by the first two authors, in accordance with predefined data fields.

Outcome measures:

The primary outcomes included functional motor abilities, daily activity and regeneration rate. Secondary outcomes included coaptation technique and animal model.

Results:

This review yielded 267 articles, of which, after completion of the screening, 49 studies were analyzed. There were 1425 animals in those 49 studies, being rats, mice, guinea pigs, rabbits, cats and dogs the different pre-clinical models. The nerves used were classified into three groups: head and neck (11), forelimb (8) and hindlimb (30). The techniques used to perform the coaptation were: microsuture (46), glue (12), laser (8) and mechanical (2). The follow-up examinations were histology (43), electrophysiological analysis (24) and behavioral observation (22).

Conclusion:

The most widely used animal model in the study of peripheral nerve repair is the rat. Other animal models are also used but the cost-benefit of the rat model provides several strengths over the others. Suture techniques are currently the first option for nerve repair, but the use of glues, lasers and bioengineering materials is increasing. Hence, further research in this field is required to improve clinical practice.

Tendon Transfers in Foot Drop

The common peroneal nerve is the most commonly injured nerve in the lower extremity. Peroneal nerve pathology results in loss of dorsiflexion at the tibiotalar joint, loss of eversion at the subtalar joint, and loss of extension of toes resulting in foot drop. The varied etiology of the problem is discussed. The various treatment modalities like conservative management, steroid therapy, nerve decompression, nerve repair, or reconstruction are described, but due to uncertain outcomes after primary nerve procedures, secondary procedures like tendon transfers often end up as definitive treatment. The rationale and technique of tibialis posterior transfer is discussed in detail.

Nerve injury in severe trauma with upper extremity involvement: evaluation of 49,382 patients from the TraumaRegister DGU® between 2002 and 2015

BACKGROUND

Peripheral nerve injury (PNI) as an adjunct lesion in patients with upper extremity trauma has not been investigated in a Central European setting so far, despite of its devastating long-term consequences. This study evaluates a large multinational trauma registry for prevalence, mechanisms, injury severity and outcome characteristics of upper limb nerve lesions.

METHODS

After formal approval the TraumaRegister DGU® (TR-DGU) was searched for severely injured cases with upper extremity involvement between 2002 and 2015. Patients were separated into two cohorts with regard to presence of an accompanying nerve injury. For all cases demographic data, trauma mechanism, concomitant lesions, severity of injury and outcome characteristics were obtained and group comparisons performed.

RESULTS

About 3,3% of all trauma patients with upper limb affection (n = 49,382) revealed additional nerve injuries. PNI cases were more likely of male gender (78,6% vs.73,2%) and tended to be significantly younger than their counterparts without nerve lesions (mean age 40,6 y vs. 47,2 y). Motorcycle accidents were the most frequently encountered single cause of injury in PNI patients (32,5%), whereas control cases primarily sustained their trauma from high or low falls (32,2%). Typical lesions recognized in PNI patients were fractures of the humerus (37,2%) or ulna (20,3%), vascular lacerations (arterial 10,9%; venous 2,4%) and extensive soft tissue damage (21,3%). Despite of similar average trauma severity in both groups patients with nerve affection had a longer primary hospital stay (30,6 d vs. 24,2 d) and required more subsequent inpatient rehabilitation (36,0% vs. 29,2%).

CONCLUSION

PNI complicating upper extremity trauma might be more commonly encountered in Central Europe than suggested by previous foreign studies. PNI typically affect males of young age who show significantly increased length of hospitalization and subsequent need for inpatient rehabilitation. Hence these lesions induce extraordinary high financial expenses besides their impact on health related quality of life for the individual patient. Further research is necessary to develop specific prevention strategies for this kind of trauma.

Nerve injury in severe trauma with upper extremity involvement: evaluation of 49,382 patients from the TraumaRegister DGU® between 2002 and 2015

BACKGROUND

Peripheral nerve injury (PNI) as an adjunct lesion in patients with upper extremity trauma has not been investigated in a Central European setting so far, despite of its devastating long-term consequences. This study evaluates a large multinational trauma registry for prevalence, mechanisms, injury severity and outcome characteristics of upper limb nerve lesions.

METHODS

After formal approval the TraumaRegister DGU® (TR-DGU) was searched for severely injured cases with upper extremity involvement between 2002 and 2015. Patients were separated into two cohorts with regard to presence of an accompanying nerve injury. For all cases demographic data, trauma mechanism, concomitant lesions, severity of injury and outcome characteristics were obtained and group comparisons performed.

RESULTS

About 3,3% of all trauma patients with upper limb affection (n = 49,382) revealed additional nerve injuries. PNI cases were more likely of male gender (78,6% vs.73,2%) and tended to be significantly younger than their counterparts without nerve lesions (mean age 40,6 y vs. 47,2 y). Motorcycle accidents were the most frequently encountered single cause of injury in PNI patients (32,5%), whereas control cases primarily sustained their trauma from high or low falls (32,2%). Typical lesions recognized in PNI patients were fractures of the humerus (37,2%) or ulna (20,3%), vascular lacerations (arterial 10,9%; venous 2,4%) and extensive soft tissue damage (21,3%). Despite of similar average trauma severity in both groups patients with nerve affection had a longer primary hospital stay (30,6 d vs. 24,2 d) and required more subsequent inpatient rehabilitation (36,0% vs. 29,2%).

CONCLUSION

PNI complicating upper extremity trauma might be more commonly encountered in Central Europe than suggested by previous foreign studies. PNI typically affect males of young age who show significantly increased length of hospitalization and subsequent need for inpatient rehabilitation. Hence these lesions induce extraordinary high financial expenses besides their impact on health related quality of life for the individual patient. Further research is necessary to develop specific prevention strategies for this kind of trauma.