The Posteromedial Approach for Harvesting Hamstring Autografts Results in Fewer Incidents of Saphenous Nerve Injury Compared to the Conventional Anteromedial Approach: A Systematic Review and Meta-Analysis.

Background: The hamstring autograft can be harvested using various skin incisions, such as vertical, transverse, and oblique incisions, and from different localizations, including anteromedial and posteromedial harvest sites. The aim of this study was to compare studies on the anteromedial and posteromedial approaches for hamstring autograft harvest in terms of clinical outcomes, saphenous nerve injury, infection, operative time, graft length, incision length, range of motion, and patient satisfaction. Methods: Following the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, a search was conducted in PubMed and Scopus, focusing on studies comparing anteromedial and posterior approaches for hamstring harvest. This study was registered with the PROSPERO International Prospective Register of Systematic Reviews (CRD42023450249). Methodological quality was evaluated using the Modified Coleman Methodology Score. Odds ratios (ORs) and mean differences (MDs) quantified dichotomous and continuous outcomes, respectively. Results: Five articles, involving 405 knees, underwent analysis. Four studies were level 3 evidence, while 1 was level 1. The anteromedial hamstring harvest showed higher rates of saphenous nerve injury (OR, 9.77; 95% confidence interval [CI], 2.19-43.65; p = 0.003) and longer operative times, with an MD of about 13 minutes (MD, 13.33; 95% CI, 0.68-25.97; p = 0.04), compared to the posteromedial approach. The anteromedial method yielded a longer semitendinosus graft, with an MD of about 17 mm (MD, 17.57; 95% CI, 7.17-27.98; p = 0.0009). However, no significant differences existed in range of motion, flexion contracture, unintentional graft harvest, infection rates, and patient-reported outcomes. Notably, the posteromedial group reported higher cosmetic satisfaction, with 92% being very satisfied, compared to the anteromedial group with 80% (p = 0.005). However, overall satisfaction levels were similar between the 2 groups (p = 0.35), with a very satisfied rate of 72% for the anteromedial group and 78% for the posteromedial group. Conclusions: The anteromedial hamstring harvest showed greater saphenous nerve injury and longer operative times compared to the posteromedial approach, along with a longer graft. However, no significant differences were observed in the range of motion, flexion contracture, graft harvest, infection, or patient outcomes.

Positive effect of ulnar nerve fascicle transfer to musculocutaneous nerve seeded with allogeneic adipose tissue derived stem cells on nerve regeneration for repairing upper brachial plexus injury in a rat model: A preliminary study.

BACKGROUND: Traumatic peripheral nerve injury, with an annual incidence reported to be approximately 13-23 per 100,000 people, is a serious clinical condition that can often lead to significant functional impairment and permanent disability. Although nerve transfer has become increasingly popular in the treatment of brachial plexus injuries, satisfactory results cannot be obtained even with total nerve root transfer, especially after serious injuries. To overcome this problem, we hypothesize that the application of stem cells in conjunction with nerve transfer procedures may be a viable alternative to more aggressive treatments that do not result in adequate improvement. Similarly, some preliminary studies have shown that adipose stem cells combined with acellular nerve allograft provide promising results in the repair of brachial plexus injury. The purpose of this study was to assess the efficacy of combining adipose-derived stem cells with nerve transfer procedure in a rat brachial plexus injury model. METHODS: Twenty female Wistar rats weighing 300-350 g and aged 8-10 weeks were randomly divided into two groups: a nerve transfer group (NT group) and a nerve transfer combined adipose stem cell group (NT and ASC group). The upper brachial plexus injury model was established by gently avulsing the C5-C6 roots from the spinal cord with microforceps. A nerve transfer from the ulnar nerve to the musculocutaneous nerve (Oberlin procedure) was performed with or without seeded allogeneic adipose tissue-derived stem cells. Adipose tissue-derived stem cells at a rate of 2 × 106 cells were injected locally to the surface of the nerve transfer area with a 23-gauge needle. Immunohistochemistry (S100 and PGP 9.5 antibodies) and electrophysiological data were used to evaluate the effect of nerve repair 12 weeks after surgery. RESULTS: The mean latency was significantly longer in the NT group (2.0 ± 0.0 ms, 95% CI: 1.96-2.06) than in the NT and ASC group (1.7 ± 0.0 ms, 95% CI: 1.7-1.7) (p < .001). The mean peak value was higher in the NT group (1.7 ± 0.0 mV, 95% CI: 1.7-1.7) than in the NT and ASC group (1.7 ± 0.3 mV, 95% CI: 1.6-1.9) with no significant difference (p = .61). Although S100 and PGP 9.5 positive areas were observed in higher amounts in the NT and ASC group compared to the NT group, the differences were not statistically significant (p = .26 and .08, respectively). CONCLUSIONS: This study conducted on rats provides preliminary evidence that adipose-derived stem cells may have a positive effect on nerve transfer for the treatment of brachial plexus injury. Further studies with larger sample sizes and longer follow-up periods are needed to confirm these findings.

End-to-side neurorrhaphy in the reconstruction of peripheral segmental neural loss: an experimental study.

PURPOSE: To evaluate the effects on peripheral neural regeneration of the end-to-side embracing repair technique compared to the autograft repair technique in Wistar rats. METHODS: Fifteen male Wistar rats were divided into three groups with five animals each: denervated group (GD), autograft group (GA), and embracing group (EG). For the evaluation, the grasping test, electroneuromyography (ENMG), and muscle weight assessment were used. RESULTS: Muscle weight assessment and ENMG did not show significant neural regeneration at the end of 12 weeks in the DG and GE groups, but only in GA. The grasping test showed an increase in strength between the surgery and the fourth week in all groups, and only the GA maintained this trend until the 12th week. CONCLUSIONS: The present study indicates that the neural regeneration observed in the end-to-side embracing neurorrhaphy technique, in the repair of segmental neural loss, is inferior to autograft repair in Wistar rats.

The effect of injury area on the success of treatment in digital nerve injury.

INTRODUCTION: The main objective of the current study is to investigate variations in postoperative outcomes that follow digital nerve repair in Zone 1 and Zone 2, respectively. We hope that by carrying out this investigation, we will be able to identify which zone has better sensation recovery and patient-reported outcomes, allowing us to identify the best way of conducting surgery for specific types of injuries. MATERIALS AND METHODS: A retrospective cohort study was conducted in patients with digital nerve injuries treated in a designated hand surgery clinic between January 2021 and December 2023. The study was guided by ethical consideration, where all participants gave their informed consent. Surgical interventions involved primary repair, autograft/allograft nerve grafting, nonsurgical approaches, as well as conduit repair in which results were determined using objective measures and patient feedback. RESULTS: Direct repair emerged superior among injuries of Zone 1 and Zone 2 with high success rates and good patient-reported outcomes. In general, injuries in Zone 1 had better sensory recovery than injuries in Zone 2 and this was associated with higher levels of satisfaction. Comparisons using statistical methods confirmed that direct repair outperformed other modalities. CONCLUSION: More importantly, the comparison of this study shows that repairs in Zone 1 are more successful than those in Zone 2 revealing direct repair as a superior method for digital nerve injuries. The difference is crucial because it suggests that surgical efficiency may depend on where the injury is. This means that direct repair should be given priority over the two zones, although surgeons will need to watch out for challenges related to Zone 2 injuries and adjust their strategies accordingly to obtain the best patient outcomes possible.

Supercharged end-to-side anterior interosseous nerve transfer to restore intrinsic function in high ulnar nerve injury: a prospective cohort study.

BACKGROUND: High ulnar nerve injuries is known to have unfavorable motor outcomes compared to other peripheral nerve injuries in the upper extremity. Functional muscle recovery after peripheral nerve injury depends on the time to motor end plate reinnervation and the number of motor axons that successfully reach the target muscle. The purpose of this study is to assess the functional recovery, and complications following performing supercharge end-to-side (SETS) anastomosis for proximal ulnar nerve injuries. Our study focuses on the role of SETS in the recovery process of high ulnar nerve injury. PATIENT AND METHODS: This study is a prospective, single-arm, open-label, case series. The original proximal nerve pathology was dealt with according to the cause of injury, then SETS was performed distally. The follow-up period was 18 months. We compared the neurological findings before and after the procedure. A new test was used to show the effect of SETS on recovery by performing a Lidocaine proximal ulnar nerve block test. RESULTS: Recovery of the motor function of the ulnar nerve was evident in 33 (86.8%) patients. The mean time to intrinsic muscle recovery was 6.85 months ± 1.3, only 11.14% of patients restored protective sensation to the palm and finger and 86.8% showed sensory level at the wrist level at the end of the follow-up period. Lidocaine block test was performed on 35 recovered patients and showed no change in intrinsic hand function in 31 patients. CONCLUSION: SETS exhibit a remarkable role in the treatment of high ulnar nerve damage. SETS transfer can act as a nerve transfer that can supply intrinsic muscles by its fibers and allows for proximal nerve regeneration. We believe that this technique improves recovery of hand motor function and allows recovery of sensory fibers when combined with treating the proximal lesion. TRIAL REGISTRATION: Approved by Research Ethics Committee of Faculty of Medicine- Cairo University on 01/09/2021 with code number: MD-215-2021.

Multilevel neurium-mimetic individualized graft via additive manufacturing for efficient tissue repair.

Complicated peripheral nerve injuries or defects, especially at branching sites, remain a prominent clinical challenge after the application of different treatment strategies. Current nerve grafts fail to match the expected shape and size for delicate and precise branched nerve repair on a case-by-case basis, and there is a lack of geometrical and microscale regenerative navigation. In this study, we develop a sugar painting-inspired individualized multilevel epi-/peri-/endoneurium-mimetic device (SpinMed) to customize natural cues, featuring a selectively protective outer sheath and an instructive core, to support rapid vascular reconstruction and consequent efficient neurite extension along the defect area. The biomimetic perineurium dictates host-guest crosslinking in which new vessels secrete multimerin 1 binding to the fibroin filler surface as an anchor, contributing to the biological endoneurium that promotes Schwann cell homing and remyelination. SpinMed implantation into rat sciatic nerve defects yields a satisfactory outcome in terms of structural reconstruction, with sensory and locomotive function restoration. We further customize SpinMed grafts based on anatomy and digital imaging, achieving rapid repair of the nerve trunk and branches superior to that achieved by autografts and decellularized grafts in a specific beagle nerve defect model, with reliable biosafety. Overall, this intelligent art-inspired biomimetic design offers a facile way to customize sophisticated high-performance nerve grafts and holds great potential for application in translational regenerative medicine.

Interpretation of Data from Translational Rodent Nerve Injury and Repair Models.

This article highlights the use of rodents as preclinical models to evaluate the management of nerve injuries, describing the pitfalls and value from rodent nerve injury and regeneration outcomes, as well as treatments derived from these rodent models. The anatomic structure, size, and cellular and molecular differences and similarities between rodent and human nerves are summarized. Specific examples of success and failure when assessing outcome metrics are presented for context. Evidence for translation to clinical practice includes the topics of electrical stimulation, Tacrolimus (FK506), and acellular nerve allografts.

Physiology of Nerve Regeneration: Key Factors Affecting Clinical Outcomes.

Functional recovery after peripheral nerve injuries is disappointing despite surgical advances in nerve repair. This review summarizes the relatively short window of opportunity for successful nerve regeneration due to the decline in the expression of growth-associated genes and in turn, the decline in regenerative capacity of the injured neurons and the support provided by the denervated Schwann cells, and the atrophy of denervated muscles. Brief, low-frequency electrical stimulation and post-injury exercise regimes ameliorate these deficits in animal models and patients, but the misdirection of regenerating nerve fibers compromises functional recovery and remains an important area of future research.

Nerve Allografts: Current Utility and Future Directions.

Processed nerve allograft is a widely accepted tool for reconstructing peripheral nerve defects. Repair parameters that need to be considered include gap length, nerve diameter, nerve type (motor, sensory, or mixed), and the soft tissue envelope. Although the use of processed nerve allograft must be considered based on each unique clinical scenario, a rough algorithm can be formed based on the available animal and clinical literature. This article critically reviews the current surgical algorithm, defines the role of processed nerve allograft compared with nerve autograft, and discusses how this role may change in the future.

Alternative Nerve Coaptations: End-To-Side and Beyond.

Modern end-to-side (ETS) nerve transfers have undergone several permutations since the early 1990's. Preclinical data have revealed important mechanisms and patterns of donor axon outgrowth into the recipient nerves and target reinnervation. The versatility of ETS nerve transfers can also potentially address several processes that limit functional recovery after nerve injury by babysitting motor end-plates and/or supporting the regenerative environment within the denervated nerve. Further clinical and basic science work is required to clarify the ideal clinical indications, contraindications, and mechanisms of action for these techniques in order to maximize their potential as reconstructive options.

Polyethylene Glycol-Fusion Repair of Peripheral Nerve Injuries.

Axons successfully repaired with polyethylene glycol (PEG) fusion tecnology restored axonal continuity thereby preventing their Wallerian degeneration and minimizing muscle atrophy. PEG fusion studies in animal models and preliminary clinical trials involving patients with digital nerve repair have shown promise for this therapeutic approach. PEG fusion is safe to perform, and given the enormous potential benefits, there is no reason not to explore its therapeutic potential.

Nerve Autograft: Preservation of a Lost Art.

Nerve autografts involve the transplantation of a segment of the patient's own nerve to bridge a nerve gap. Autografts provide biological compatibility, support for axonal regeneration, and the ability to provide an anatomic scaffold for regrowth that other modalities may not match. Disadvantages of the autograft include donor site morbidity and the extra operative time needed to harvest the graft. Nevertheless, nerve autografts such as the sural nerve remain the gold standard in reconstructing nerve gaps, but a multitude of factors need to be favorable in order to garner reliable, consistent outcomes.

Bioengineered Nerve Conduits and Wraps.

Peripheral nerve injuries are prevalent and their treatments present significant challenges. Among the various reconstructive options, nerve conduits and wraps are popular choices. Advances in bioengineering and regenerative medicine have led to the development of new biocompatible materials and implant designs that offer the potential for enhanced neural recovery. Cost, nerve injury type, and implant size must be considered when deciding on the ideal reconstructive option.

Evaluating Outcomes Following Nerve Repair: Beyond the Medical Research Council.

Peripheral nerve injuries are common and remain a significant health challenge. Outcome measurements are used to evaluate injury, monitor recovery after nerve repair, and compare scientific advances. Clinical judgement is required to determine which available tools are most applicable, which requires a vast understanding of the available outcome measurements. In this article we discuss the highest yield tools available for clinical application.

Therapeutic Electrical Stimulation for Surgeons: How it Works and How to Apply it.

Electrical stimulation (ES) enhances peripheral nerve inherent regeneration capacity by promoting accelerated axonal outgrowth and selectivity toward appropriate motor and sensory targets. These effects lead to significantly improved functional outcomes and shorter recovery time. Electrical stimulation can be applied intra-operatively or immediately post-operatively. Active clinical trials are looking into additional areas of application, length of stimulation, and functional outcomes.

Growth Factors to Enhance Nerve Regeneration: Approaching Clinical Translation.

Following nerve injury, growth factors (GFs) are transiently upregulated in injured neurons, proliferating Schwann cells, and denervated muscle and skin. They act on these same cells and tissues to promote nerve regeneration and end-organ reinnervation. Consequently, much attention has been focused on developing GF-based therapeutics. A major barrier to clinical translation of GFs is their short half-life. To provide sustained GF treatment to the affected nerve, muscle, and skin in a safe and practical manner, engineered drug delivery systems are needed. This review highlights recent advancements in GF-based therapeutics and discusses the remaining hurdles for clinical translation.

Clinical Insights and Optimization of Surgical Approach for Lateral Femoral Cutaneous Nerve Injury/Entrapment: A Comprehensive Analysis of 184 Cases.

BACKGROUND: Entrapment or injury of the lateral femoral cutaneous nerve (LFCN) is being recognized with increasing frequency, often requiring a surgical approach to relieve symptoms. The presence of anatomic variations can lead to errors in diagnosis and intraoperative decision-making. METHODS: This study presents the experience of a single surgeon (T.W.T.) in managing 184 patients referred with clinical issues related to the LFCN. A comprehensive review of these cases was conducted to develop a prospective surgical management algorithm. Data on the LFCN's anatomic course, pain relief outcomes, comorbidities, body mass index, and sex were extracted from patients' medical charts and operative notes. Pain relief was assessed subjectively, categorized into "excellent relief" for complete pain resolution, "good" for substantial pain reduction with some residual discomfort, and "failure" for cases with no pain relief necessitating reoperation. RESULTS: The decision tree is dichotomized based on the mechanism of LFCN pathology: compression (requiring neurolysis) versus history of trauma, surgery, and/or obesity (requiring resection). Forty-seven percent of the patients in this series had an anatomic variation. It was found that failure to relieve symptoms of compression often indicated the presence of anatomic variation of the LFCN or intraneural changes consistent with a neuroma, even if adequate decompression was achieved. With respect to pain relief as the outcome measure, recognition of LFCN anatomic variability and use of this algorithm resulted in 75% excellent results, 10% good results, and 15% failures. Twenty-seven of the 36 failures originally had neurolysis as the surgical approach. Twelve of those failures had a second surgery, an LFCN neurectomy, resulting in 10 excellent, 1 good, and 1 persistent failure. CONCLUSION: This article establishes an algorithm for the surgical treatment of MP, incorporating clinical experience and anatomical insights to guide treatment decisions. Criteria for considering neurectomy may include a history of trauma, prior local surgery, anatomical LFCN variations, and severe nerve damage due to chronic compression.

[Progress on application of hydrogels in the field of peripheral nerve injury repair].

As one of the common traumatic diseases in clinical practice, peripheral nerve injury (PIN) often causes nerve pain, abnormal reflexes, autonomic disorders, and even sensorimotor disorders due to the slow regeneration rate after injury, which seriously affects body function. Even as the gold standard of treatment, autologous nerve transplantation has limitations such as limited donor area and donor injury, which greatly limits its clinical application effect. Therefore, the preparation of artificial nerve grafts suitable for clinical practice has become the future development trend of peripheral nerve injury treatment, and the repair of injury defects and the promotion of nerve regeneration have also become research hotspots in tissue engineering and regenerative medicine. In recent years, extensive research has been carried out on nerve guidance conduits (NGCs) in the field of nerve regeneration and repair, in which scaffold materials and internal fillers have also become the focus of research as the core elements of neural catheters, and a series of achievements have been made in the application of new materials, embedding stem cells/precursor cells, and developing trophic factors and drug-loaded sustained-release systems. Therefore, this paper focuses on the application progress of hydrogel and its related derivative materials in the field of peripheral nerve injury repair, and provides new ideas for promoting the related research of tissue engineering and clinical medicine.

Upper Extremity Nerve Transfers for Treatment of Nerve Injury After Cervical Spine Surgery: A Single-Center Retrospective Review.

PURPOSE: Nerve transfers to restore or augment function after spinal cord injury is an expanding field. There is a paucity of information, however, on the use of nerve transfers for patients having undergone spine surgery. The incidence of neurologic deficit after spine surgery is rare but extremely debilitating. The purpose of this study was to describe the functional benefit after upper extremity nerve transfers in the setting of nerve injury after cervical spine surgery. METHODS: A single-center retrospective review of all patients who underwent nerve transfers after cervical spine surgery was completed. Patient demographics, injury features, spine surgery procedure, nerve conduction and electromyography study results, time to referral to nerve surgeon, time to surgery, surgical technique and number of nerve transfers performed, complications, postoperative muscle testing, and subjective outcomes were reviewed. RESULTS: Fourteen nerve transfers were performed in 6 patients after cervical spine surgery. Nerve transfer procedures consisted of a transfer between a median nerve branch of flexor digitorum superficialis into a biceps nerve branch, an ulnar nerve branch of flexor carpi ulnaris into a brachialis nerve branch, a radial nerve branch of triceps muscle into the axillary nerve, and the anterior interosseous nerve into the ulnar motor nerve. Average patient age was 55 years; all patients were male and underwent surgery on their left upper extremity. Average referral time was 7 months, average time to nerve transfer was 9 months, and average follow-up was 21 months. Average preoperative muscle grading was 0.9 of 5, and average postoperative muscle grading was 4.1 of 5 ( P < 0.00001). CONCLUSIONS: Upper extremity peripheral nerve transfers can significantly help patients regain muscle function from deficits secondary to cervical spine procedures. The morbidity of the nerve transfers is minimal with measurable improvements in muscle function.

Surgery for mononeuropathies.

Advancement in microsurgical techniques and innovative approaches including greater use of nerve and tendon transfers have resulted in better peripheral nerve injury (PNI) surgical outcomes. Clinical evaluation of the patient and their injury factors along with a shift toward earlier time frame for intervention remain key. A better understanding of the pathophysiology and biology involved in PNI and specifically mononeuropathies along with advances in ultrasound and magnetic resonance imaging allow us, nowadays, to provide our patients with a logical and sophisticated approach. While functional outcomes are constantly being refined through different surgical techniques, basic scientific concepts are being advanced and translated to clinical practice on a continuous basis. Finally, a combination of nerve transfers and technological advances in nerve/brain and machine interfaces are expanding the scope of nerve surgery to help patients with amputations, spinal cord, and brain lesions.