Bridging the neural gap

Silicon-induced biofilm improves peripheral nerve defect in rats mediated by VEGF/VEGFR2/ERK

Background: Injury of peripheral nerve capable of regeneration with much poorer prognosis affects people's life quality. The recovery of nerve function after transplantation for peripheral nerve injury remain a worldwide problem. Silicon-induced biofilms as vascularized biological conduits can promote nerve regeneration by encapsulating autologous or allogeneic nerve graft.Objective: We proposed to explore the effect of silicon-induced biofilms on nerves regeneration and whether the VEGF/VEGFR2/ERK pathway was involved in the present study.Methods: Biofilms around the transplanted nerves in peripheral nerve injury rats were induced by silicon. Vascularization and proteins related to VEGF/VEGFR2/ERK were measured. Pathology and morphology of nerves were investigated after encapsulating the transplanted nerves by silicon-induced biofilms.Results: Our results indicated that the biofilms induced by silicon for 6 weeks showed the most intensive vascularization and the optimal effect on nerve regeneration. Moreover, silicon-induced biofilms for 4, 6 and 8 weeks could significantly secrete VEGF with the highest content at week 6 after induction. VEGFR2, VEGF, p-VEGFR2, ERK1, ERK2, p-ERK1 and p-ERK2 were expressed in the biofilms. p-VEGFR2, p-ERK1 and p-ERK2 expression were different at each time point and significantly increased at week 6 compared with that at week 4 or week 8 which was consistent with that 6 week of was the optimum time for biofilms induction to improve the nerve repair after peripheral nerve injury.Conclusion: Our results suggested that combination of silicon-induced autologous vascularized biofilm and autologous transplantation may promote the repair of rat sciatic nerve defect quickly through VEGF/VEGFR2/ERK pathway.

An Updated Surgical Approach of Using Flap and Cutaneous Nerve in the Lateral Arm to Reconstruct Complex Injuries of the Forearm and Hand: A Case Series Study

BACKGROUND

Complex injuries involving the nerves and other soft tissues in the forearm and hand lead to functional and aesthetic defects. In such situations, multiple types of nerve autografts and flap donor sites are available. However, multiple donor sites cause donor morbidity in different locations and may lead to awkward operational positions. Therefore, based on the anatomical characterization, we aimed to modify the utilization of the lateral arm donor site for reconstruction, which restricts donor morbidity in the affected upper extremity.

METHODS

We report a case series (N = 6) using a lateral arm flap (LAF) to reconstruct complex soft tissue defects in the forearm, palm, and finger. The posterior antebrachial cutaneous nerve (PACN) is the primary option for nerve bridging, whereas the LAF can carry the lower lateral brachial cutaneous nerve (LBCN) as a sensory flap. Once the PACN was insufficient, the LBCN was harvested simultaneously. All the cases included in this study were performed between January 2012 and August 2021. Demographic information, flap and nerve characteristics, complications, and hand function were analyzed.

RESULTS

The LAF plus PACN or plus LBCN as nerve autograft, both successfully repaired 6 complex injuries: 2 cases in the forearm side, 1 in the hand palm, and 3 in the finger defects. Posterior antebrachial cutaneous nerve was the most used (8-15 cm), and LBCN plus PACN was used to bridge nerve defects when necessary (in total, 20 and 21 cm). The average follow-up time was 19.7 months. The disabilities of the arm, shoulder and hand score ranged between 6 and 12, and the mean 2-point discrimination values ranged between 6 and 12. The Semmes-Weinstein monofilament test result was under 5.46. In addition, 2 patients underwent a secondary debulking surgery. The average length of hospital stay was 10.4 days. Hematoma occurred in 2 cases, and all patients reported numbness in the donor nerve innervated areas.

CONCLUSIONS

This surgical refinement can reconstruct complex injuries in the forearm and hand. In addition, this approach restricts donor morbidity in the affected limb, comforts the operational position, and is achieved under brachial plexus anesthesia.

Biological nerve conduit model with de-epithelialized human amniotic membrane and adipose-derived mesenchymal stem cell sheet for repair of peripheral nerve defects

In this study, a biological conduit, consisting of an adipocyte-derived mesenchymal stem cell (AdMSCs) sheet and amniotic membrane (AM), was designed for the reconstruction of peripheral nerve defects. To evaluate the effect of the produced conduit on neural regeneration, a 10-mm sciatic nerve defect was created in rats, and experiments were carried out on six groups, i.e., sham control group (SC), negative control group (NC), nerve autograft group (NG), the biological conduit (AdMSCs + AM) group, the commercial PGA tube conduit (PGA) group, and the conduit only consisting of AM (AM) group. The effects of different nerve repair methods on the peripheral nerve and gastrocnemius muscle were evaluated by functional, histological, and immunohistochemical tests. When the number of myelinated axons was compared between the groups of AdMSCs + AM and PGA, it was higher in the AdMSCs + AM group (p < 0.05). The percentage of gastrocnemius collagen bundle area of AdMSCs + AM group was found to be statistically lower than the PGA group (p < 0.05). The muscle fiber diameter of AdMSCs + AM group was lower than that of the NG group, but significantly higher than that of the PGA group and the AM group (p < 0.001). Muscle weight index was significantly higher in the AdMSCs + AM group compared to the PGA group (p < 0.05). It was observed that nerve regeneration was faster in the AdMSCs + AM group, and there was an earlier improvement in pin-prick score and sciatic functional index compared to the PGA group and the AM group. In conclusion, the biological conduit prepared from the AdMSCs sheet and AM is regarded as a new biological conduit that can be used as an alternative treatment method to nerve autograft in clinical applications.

Effect of acellular nerve scaffold containing human umbilical cord-derived mesenchymal stem cells on nerve repair and regeneration in rats with sciatic nerve defect

Background

The aim of the present study was to investigate the effect of acellular nerve scaffold (ANS) containing human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) on nerve repair and regeneration in rats with sciatic nerve defect.

Methods

Sciatic nerve trunks were removed from 6 female Sprague-Dawley (SD) rats, and ANS was prepared by lyophilization + enzymatic method and divided into A, B, C, D and E groups according to different treatment times. hUC-MSCs were isolated from the collected umbilical cords and cultured, and then ANS-hUC-MSCs complexes were made. The other 24 adult female SD rats were randomly divided into the control, autograft, ANS, and ANS-hUC-MSCs groups, and a rat model of sciatic nerve defect was established. Hematoxylin-eosin (HE) staining, Luxol fast blue (LFB) staining, Masson staining, and scanning electron microscopy were used to observe the morphology and tissue structure of ANS. The performance of ANS was evaluated by mechanical detection, and hydroxyproline (HYP) content was evaluated using a biochemical kit. Flow cytometry was adopted to detect the levels of hUC-MSCs surface antigens CD29, CD44, and CD34, as well as electrophysiological detection and muscle wet weight recovery rate for measuring rat muscle performance.

Results

ANS was prepared according to group A method and had good mechanical properties, with less residues of cells and myelin, and higher HYP content, indicating that this scaffold had the best performance. ANS-hUC-MSCs significantly reduced myelin injury in the sciatic nerve, and increased axonal regeneration, effectively improving sciatic nerve injury in rats. In addition, ANS-hUC-MSCs significantly increased compound muscle action potential (CMAP), nerve conduction velocity (NCV), and muscle wet weight, and reduced muscle atrophy.

Conclusions

ANS containing hUC-MSCs can promote nerve repair and regeneration in rats with sciatic nerve defects.

State of the Art and Advances in Peripheral Nerve Surgery

This review is intended to describe and actualize the basic knowledge of the three basic entities that affect the peripheral nerve system and can be treated by surgery: nerve trauma, chronic nerve compressions, and tumors.Regarding trauma, emphasis is given on the timing of surgery, given the fact that the moment in which the surgery is performed and the employed microsurgical reconstruction technique are the most important factors in the final result. Open lesions with associated nerve injury should be managed with an early exploration carried out before 7 days. Closed injuries are usually deferred, with few exceptions, from 3 to 6 months after the trauma.In turn, chronic compressions require an appropriate clinical, neurophysiological, and imaging diagnosis. Isolated sensory symptoms can be treated actively though without surgery: motor signs like atrophy should be regarded as a sign for immediate surgery, as a deferred treatment might cause an irreversible nerve and muscular damage. Endoscopic approaches are a valuable tool for treatment in selected neuropathies.Finally, nerve tumors demand a thorough preoperative evaluation, as benign tumors are treated in a very different way when compared to malignant lesions. Benign tumors can usually be safely and completely resected without sacrificing the nerve of origin. When malignancy is confirmed, extensive resection to optimize patient survival is the main objective, potentially at the expense of neurological function. This may then be followed by adjuvant radiation and/or chemotherapy, depending on the nature of the tumor and the completeness of resection attained. The role of nerve biopsy remains controversial, and several modern diagnostic techniques might be helpful.

Effects of Adipose-Derived Mesenchymal Stem Cells and Human Amniotic Membrane on Sciatic Nerve Repair in Rats

Background: Peripheral nerve injuries remain a great challenge for microsurgery despite the significant progress in recent decades. The current gold standard is autogenous nerve grafting with a success rate as low as 50% in long gaps. Current studies have focused on finding alternative methods for bridging nerve defects. Previous data have demonstrated the role of human amniotic membrane in stimulating neural regeneration. On the other hand, adipose-derived mesenchymal stem cells can differentiate into all three germ layers and could support nerve repair. The purpose of this study was to compare the role of the human amniotic membrane with and without adipose tissue stem cells in sciatic nerve injury with gap in rats. Objectives: We aimed to evaluate the effectiveness of the human amniotic membrane with and without adipose-derived mesenchymal stem cells in sciatic nerve injury with gap in rats. Methods: Twenty-four male Wistar rats in four random groups were used in our study. In the first group, the nerve gap was repaired using the inverse resected nerve segment (Control group), the second group was repaired with a human amniotic membrane (AM group), the third group was repaired with an amnion sheet with seeded adipose-derived mesenchymal stem cells (AM/ADMSCs group), and the last group was not repaired, and both stumps were sutured to muscles. Results: All the animals underwent the procedures and survived without complication. The sciatic function index and hot plate test results were significantly improved in the AM and AM/ADMSCs groups compared to the Control group (as a gold standard of care) (P>0.05). Based on histopathology findings, regenerative nerve fibers were seen in the implanted area of both AM and AM/ADMSCs groups; however, nerve fibers were surrounded by significant fibrosis (scar formation) in the AM/ADMSCs group. The axon count in the Control group was significantly higher than both experimental groups (P < 0.01). Conclusions: Our study showed the role of amniotic membrane in the promotion of nerve regeneration in sciatic nerve injury with a gap, but adding adipose-derived mesenchymal stem cells not only has no extra benefits, but also causes more tissue scar.

Nanochannel-Based Poration Drives Benign and Effective Nonviral Gene Delivery to Peripheral Nerve Tissue

While gene and cell therapies have emerged as promising treatment strategies for various neurological conditions, heavy reliance on viral vectors can hamper widespread clinical implementation. Here, the use of tissue nanotransfection as a platform nanotechnology to drive nonviral gene delivery to nerve tissue via nanochannels, in an effective, controlled, and benign manner is explored. TNT facilitates plasmid DNA delivery to the sciatic nerve of mice in a voltage-dependent manner. Compared to standard bulk electroporation (BEP), impairment in toe-spread and pinprick response is not caused by TNT, and has limited to no impact on electrophysiological parameters. BEP, however, induces significant nerve damage and increases macrophage immunoreactivity. TNT is subsequently used to deliver vasculogenic cell therapies to crushed nerves via delivery of reprogramming factor genes Etv2, Foxc2, and Fli1 (EFF). The results indicate the TNT-based delivery of EFF in a sciatic nerve crush model leads to increased vascularity, reduced macrophage infiltration, and improved recovery in electrophysiological parameters compared to crushed nerves that are TNT-treated with sham/empty plasmids. Altogether, the results indicate that TNT can be a powerful platform nanotechnology for localized nonviral gene delivery to nerve tissue, in vivo, and the deployment of reprogramming-based cell therapies for nerve repair/regeneration.

Repairing peripheral nerve defects with revascularized tissue-engineered nerve based on a vascular endothelial growth factor-heparin sustained release system

To enhance the angiogenic capacity of tissue-engineered peripheral nerves, we have constructed revascularized tissue-engineered nerves based on a vascular endothelial growth factor (VEGF)-heparin sustained release system. However, the effects of the repair of large peripheral nerve defects are not known. In this study, we used the above revascularized tissue-engineered nerve to repair large nerve defects in rats. The repair effects were observed through general observation, functional evaluation of nerve regeneration, ultrasound examination, neural electrophysiology, wet weight ratio of bilateral gastrocnemius muscle, histological evaluation, and quantitative real-time polymerase chain reaction (PCR) analysis. The results showed that the tissue-engineered peripheral nerve based on a VEGF-heparin sustained release system can achieve early vascularization and restore blood supply in the nerve graft area. The realization of early vascularization in the area of the nerve defect greatly promotes the speed of nerve regeneration and reconstruction in the area of the nerve defect, which greatly advances the process of nerve repair and reconstruction and accelerates the restoration of the normal morphological structure and function of peripheral nerves.

Chimeric Vastus Lateralis and Anterolateral Thigh Flap for Restoring Facial Defects and Dynamic Function following Radical Parotidectomy

BACKGROUND

Extirpation of malignant tumors of the parotid results in creation of a complex facial defect often in combination with facial nerve palsy. This study presents the authors' experience using vastus lateralis muscle as a chimeric flap with anterolateral thigh flap to allow both soft-tissue reconstruction and dynamic reanimation in radical parotidectomy.

METHODS

A retrospective review of the medical records of cancer patients who had undergone radical parotidectomy and reconstruction using a chimeric vastus lateralis and anterolateral thigh flap between March of 2013 and May of 2017 was performed using the Sydney Head and Neck Cancer Institute database. The return of dynamic midface movement was the primary outcome investigated. Electronic, clinician-graded facial function scale grades were used to formally assess postoperative outcomes.

RESULTS

A total of 27 patients were included in the study with an average age of 72 years (range, 31 to 88 years). Thirteen patients (48 percent) had developed dynamic function by the end of the study period. Young age predicted a more rapid return to dynamic function (p = 0.018). Both being a woman and having an intact facial nerve before surgery improved dynamic midface movement (p = 0.005 and p = 0.036, respectively). On multivariable analysis, superior midface dynamic function was associated with neurotization using midface facial nerve branches as opposed to using nerve-to-masseter alone (p = 0.05).

CONCLUSION

The chimeric vastus lateralis and anterolateral thigh flap is a suitable option for restoring defects and dynamic function following radical parotidectomy.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Effects of humeral shortening on the three-dimensional configuration of the brachial plexus: a cadaveric study

This study reports the gains in length of nerves after three different humeral shortenings. Ten brachial plexuses were dissected. The lengths of the different parts of the brachial plexus were measured using a three-dimensional digitizing system after humeral shaft shortenings of 2, 4 and 6 cm and after a standardized force of 0.588 N was used to apply tension to the plexus. The feasibility of nerve suturing was studied. Humeral shortening allowed for significant gains in lengths of the musculocutaneous (42 mm), median (41 mm), ulnar (29 mm) and radial nerves (15 mm). A 2 cm humeral shortening allowed a 2 cm nerve gap to be directly sutured in 70% to 90% of cases. This study suggests that humeral shortening could allow direct suture of nerve defects, or shorten the length of nerve grafts required to bridge a gap.

Testing of Direct Neurorrhaphy Strain

PURPOSE

To investigate the ideal suture material to test strain at nerve repair sites. Based on nerve strain tolerance, we aimed to determine which suture reliably failed by an average of 5% and a maximum of 8% strain when loaded to failure.

METHODS

The median nerve of 19 cadavers was exposed in the distal forearm, transected proximally, and attached to a spring gauge. It was marked 5 cm on either side of its midpoint to measure strain. A laceration was created at its midpoint. We performed a tension-free end-to-end repair with a single epineural suture. Load to failure of the repair site was recorded. We recorded strain at failure and mode of failure (pullout vs breakage). Eight different sutures were tested: 6-0, 8-0, 9-0, and 10-0 nylon; and 6-0, 7-0, 8-0, and 10-0 polypropylene.

RESULTS

Average strain at failure of 9-0 nylon most closely approximated 5% (4.9%). Moreover, 8-0 polypropylene and 10-0 nylon and polypropylene failed with average strains less than 5% and a maximum strain of failure less than 8%. Regardless of type, 6-0 to 8-0 caliber suture failed primarily by pullout of the suture from the epineurium whereas 9-0 and 10-0 nylon and polypropylene failed by suture breakage. Decreased precision through increased variability was seen when testing sutures failing via pullout.

CONCLUSIONS

Nylon suture size 8-0 has been advocated as the suggested intraoperative aid to test strain at nerve repair sites. Our study suggests that 9-0 nylon may be a more appropriate testing suture because of its more predictable failure via breakage and its failure by a threshold of 5% to 8% strain. Although 8-0 nylon and polypropylene may also represent reasonable testing sutures, 8-0 nylon failed on average above 5% strain, with strains exceeding 8%, and both failed via the mechanism of pullout.

CLINICAL RELEVANCE

This study's findings provide information for surgeons attempting to decide during surgery whether to perform direct nerve repair.

Current Concept in Adult Peripheral Nerve and Brachial Plexus Surgery

Peripheral nerve injuries and brachial plexus injuries are relatively frequent. Significance of these injuries lies in the fact that the majority of patients with these types of injuries constitute working population. Since these injuries may create disability, they present substantial socioeconomic problem nowadays. This article will present current state-of-the-art achievements of minimal invasive brachial plexus and peripheral nerve surgery. It is considered that the age of the patient, the mechanism of the injury, and the associated vascular and soft-tissue injuries are factors that primarily influence the extent of recovery of the injured nerve. The majority of patients are treated using classical open surgical approach. However, new minimally invasive open and endoscopic approaches are being developed in recent years—endoscopic carpal and cubital tunnel release, targeted minimally invasive approaches in brachial plexus surgery, endoscopic single-incision sural nerve harvesting, and there were even attempts to perform endoscopic brachial plexus surgery. The use of the commercially available nerve conduits for bridging short nerve gap has shown promising results. Multidisciplinary approach individually designed for every patient is of the utmost importance for the successful treatment of these injuries. In the future, integration of biology and nanotechnology may fabricate a new generation of nerve conduits that will allow nerve regeneration over longer nerve gaps and start new chapter in peripheral nerve surgery.

Cauda equina repair in the rat: Part 3. Axonal regeneration across Schwann cell-Seeded collagen foam

INTRODUCTION

Treatments for patients with cauda equina injury are limited.

METHODS

In this study, we first used retrograde labeling to determine the relative contributions of cauda equina motor neurons to intrinsic and extrinsic rat tail muscles. Next, we transected cauda equina ventral roots and proceeded to bridge the proximal and distal stumps with either a type I collagen scaffold coated in laminin (CL) or a collagen-laminin scaffold that was also seeded with Schwann cells (CLSC). Regeneration was assessed by way of serial retrograde labeling.

RESULTS

After accounting for the axonal contributions to intrinsic vs. extrinsic tail muscles, we noted a higher degree of double labeling in the CLSC group (58.0 ± 39.6%) as compared with the CL group (27.8 ± 16.0%; P = 0.02), but not the control group (33.5 ± 18.2%; P = 0.10).

DISCUSSION

Our findings demonstrate the feasibility of using CLSCs in cauda equina injury repair. Muscle Nerve 57: E78-E84, 2018.

Peripheral Nerve Regeneration: Current Status and New Strategies Using Polymeric Materials

Experiments concerning peripheral nerve regeneration have been reported since the end of the 19^th century. The need to implement an effective surgical procedure in terms of functional recovery has resulted in the appearance of several approaches to solve this problem. Nerve autograft was the first approach studied and is still considered the gold standard. Since autografts require donor harvesting, other strategies involving the use of natural materials have also been studied. Nevertheless, the results were not very encouraging and attention has moved towards the use of nerve conduits made from polymers, whose properties can be easily tailored and which allow the nerve conduit to be easily processed into a variety of shapes and forms. Some of these materials are already approved by the US Food and Drug Administration (FDA), as is presented here. Furthermore, polymers with conductive properties have very recently been subject to intensive study in this field, since it is believed that such properties have a positive influence in the regeneration of the new axons. This manuscript intends to give a global view of the mechanisms involved in peripheral nerve regeneration and the main strategies used to recover motor and sensorial function of injured nerves.

The Spinal Accessory Nerve for Functional Muscle Innervation in Facial Reanimation Surgery: An Anatomical and Histomorphometric Study

INTRODUCTION

Facial reanimation surgery is performed in severe cases of facial palsy to restore facial function. In a 1-stage procedure, the spinal accessory nerve can be used as a donor nerve to power a free gracilis muscle transplant for the reanimation of the mouth. The aim of this study was to describe the surgical anatomy of the spinal accessory nerve, provide a guide for reliable donor nerve dissection, and analyze the available donor axon counts.

METHODS

Dissections were performed on 10 nonembalmed cadavers (measurements of 20 nerves). Surgical anatomy of the spinal accessory nerve was described and distances to important landmarks were measured. Nerve biopsies were obtained of the main nerve trunk distal to the skull base, caudoposterior to the sternocleidomastoid muscle, proximal to the trapezius muscle and at the level of donor nerve harvest to analyze the myelinated axon count throughout the course of the spinal accessory nerve. The donor nerve length and available donor nerve axon count were the primary outcome parameters in this study.

RESULTS

The mean donor nerve length was 11.6 cm. The spinal accessory nerve was transferred to the mandibular angle without tension for ideal coaptation to the free muscle transplant. After retraction of the trapezius muscle, a small distal nerve branch that leaves the main nerve trunk at a 90-degree angle medially was used as a landmark to indicate the level of donor nerve transection. On average, 1400 myelinated donor axons were available for innervation of the gracilis muscle transplant.

CONCLUSIONS

This study gives a practical guide for spinal accessory nerve dissection for its application in facial reanimation as a motor source for the innervation of a free muscle transplant.

Acute Limb Shortening for Major Near and Complete Upper Extremity Amputations with Associated Neurovascular Injury: A Review of the Literature

In the setting a near or complete upper extremity amputations with significant soft tissue loss and neurovascular compromise, upper extremity surgeons are faced with the challenge of limb salvage. There are a multitude of treatment options for managing skeletal and soft tissue injuries including provisional fixation, staged reconstruction, and an acute shortening osteotomy with primary rigid internal fixation. However, many complications are associated with these techniques. Complications of provisional fixation include pin tract infection and loosening, tethering of musculotendinous units, nonunion, and additional surgeries. Staged reconstruction includes a variety of techniques: distraction osteogenesis, bone transport, or vascularized and non-vascularized structural autograft or allograft, but the risks often outweigh the benefits. Risks include nonunion, postoperative vascular complications necessitating reoperation, and the inability to return to the previous level of function at an average of 24 months. Acute shortening osteotomy with internal fixation offers the advantage of a single-stage procedure that provides for decreasing the soft tissue loss, provides a rigid platform to protect the delicate neurovascular repair, and alleviates unwanted tension at the repair sites. This review discusses the literature on the surgical treatment of severe upper extremity trauma with associated neurovascular injury over the past 75 years, and aims to evaluate the indications, surgical techniques, clinical and functional outcomes, and complications associated with acute shortening osteotomy with rigid internal fixation. Although this technique is not without risks, it is well-tolerated in the acute setting with a complication profile comparable to other techniques of fixation while remaining a single procedure.

Nerve Transfers in the Upper Extremity: A Practical User's Guide

Nerve injuries above the elbow are associated with a poor prognosis, even with prompt repair and appropriate rehabilitation. The past 2 decades have seen the development of numerous nerve transfer techniques, by which a denervated peripheral target is reinnervated by a healthy donor nerve. Nerve transfers are indicated in proximal brachial plexus injuries where grafting is not possible or in proximal injuries of peripheral nerves with long reinnervation distances. Nerve transfers represent a revolution in peripheral nerve surgery and offer the potential for superior functional recovery in severe nerve injuries. However, the techniques have not been universally adopted due in part to a misconception that nerve transfers can only be understood and performed by superspecialists. Nerve transfer procedures are not technically difficult and require no specialized equipment. Numerous transfers have been described, but there are a handful of transfers for which there is strong clinical evidence. To restore shoulder abduction and external rotation in upper trunk brachial plexus injury, the key transfers are the spinal accessory to suprascapular nerve and the medial triceps branch to axillary nerve. For elbow flexion, the flexor carpi ulnaris branch of ulnar nerve to the biceps and brachialis branches of the musculocutaneous nerve is the key transfer. For ulnar intrinsic function, the distal anterior interosseous nerve to ulnar motor branch transfer has yielded excellent functional results. Nerve transfers form a therapeutic triad with traditional tendon transfers and functional motor unit rehabilitation which, when applied appropriately, can yield excellent functional results in complex nerve injuries. Nerve transfers are a powerful yet underused tool for proximal nerve injuries, which offer hope for traditionally discouraging injuries.

Peripheral nerve repair: a hot spot analysis on treatment methods from 2010 to 2014

Therapeutic strategies for neurological deficits and for promoting nerve regeneration after peripheral nerve injuries have received much focus in clinical research. Advances in basic research in recent years have increased our understanding of the anatomy of peripheral nerves and the importance of the microenvironment. Various new intervention methods have been developed, but with varying effectiveness. In the present study, we selected 911 papers on different repair methods for peripheral nerve injury from the Web of Science and indexed in the Science Citation Index from 2010 to 2014. We quantitatively examine new repair methods and strategies using bibliometrics, and we discuss the present state of knowledge and the problems and prospects of various repair methods, including nerve transfer, neural transplantation, tissue engineering and genetic engineering. Our findings should help in the study and development of repair methods for peripheral nerve injury.

Peripheral nerve regeneration with conduits: use of vein tubes

Treatment of peripheral nerve injuries remains a challenge to modern medicine due to the complexity of the neurobiological nerve regenerating process. There is a greater challenge when the transected nerve ends are not amenable to primary end-to-end tensionless neurorraphy. When facing a segmental nerve defect, great effort has been made to develop an alternative to the autologous nerve graft in order to circumvent morbidity at donor site, such as neuroma formation, scarring and permanent loss of function. Tubolization techniques have been developed to bridge nerve gaps and have been extensively studied in numerous experimental and clinical trials. The use of a conduit intends to act as a vehicle for moderation and modulation of the cellular and molecular ambience for nerve regeneration. Among several conduits, vein tubes were validated for clinical application with improving outcomes over the years. This article aims to address the investigation and treatment of segmental nerve injury and draw the current panorama on the use of vein tubes as an autogenous nerve conduit.

The effect of humerus diaphyseal shortening on brachial plexus tension: a cadaver study

PURPOSE

To assess the extent to which diaphyseal shortening of the humerus can allow direct suture in case of rupture or transection injuries of the brachial plexus.

METHODS

The use of 3 fresh cadaver specimens allowed for the study of 6 brachial plexuses. Distance measurements were made between reference points placed on the clavicle and on different parts of the plexus. Those measurements were repeated after shortening the humerus by 2, 4, and 6 cm.

RESULTS

None of the dissected plexuses had classic anatomy. A humeral shortening of 6 cm allowed for a statistically significant reduction of length between the supraclavicular part of the plexus and the terminal branches, which did not exceed 17 mm on average. The difference of length was much greater for the specimen in which the musculocutaneous nerve did not pierce the coracobrachialis muscle proximally.

CONCLUSIONS

In clinical situations, nerve defects are usually larger than the gain observed when doing a 6-cm humeral shortening. Moreover, this procedure implies a large dissection, a functional loss of certain muscles, and a risk of humeral nonunion.

CLINICAL RELEVANCE

In the absence of extensive nerve dissection, the observed change of length is insufficient in the most brachial plexus disruptions to allow for a direct suture instead of long nerve grafts.

The influence of vascularization of transplanted processed allograft nerve on return of motor function in rats

Processed nerve allografts have become an alternative to repair segmental nerve defects, with results comparable with autografts regarding sensory recovery; however, they have failed to reproduce comparable motor recovery. The purpose of this study was to determine how revascularizaton of processed nerve allograft would affect motor recovery. Eighty-eight rats were divided in four groups of 22 animals each. A unilateral 10-mm sciatic nerve defect was repaired with allograft (group I), allograft wrapped with silicone conduit (group II), allograft augmented with vascular endothelial growth factor (group III), or autograft (group IV). Eight animals from each group were sacrificed at 3 days, and the remaining animals at 16 weeks. Revascularization was evaluated by measuring the graft capillary density at 3 days and 16 weeks. Measurements of ankle contracture, compound muscle action potential, tibialis anterior muscle weight and force, and nerve histomorphometry were performed at 16 weeks. All results were normalized to the contralateral side. The results of capillary density at 3 days were 0.99% ± 1.3% for group I, 0.33% ± 0.6% for group II, 0.05% ± 0.1% for group III, and 75.6% ± 45.7% for group IV. At 16 weeks, the results were 69.9% ± 22.4% for group I, 37.0% ± 16.6% for group II, 84.6% ± 46.6% for group III, and 108.3% ± 46.8% for group IV. The results of muscle force were 47.5% ± 14.4% for group I, 21.7% ± 13.5% for group II, 47.1% ± 7.9% for group III, and 54.4% ± 10.6% for group IV. The use of vascular endothelial growth factor in the fashion used in this study improved neither the nerve allograft short-term revascularization nor the functional motor recovery after 16 weeks. Blocking allograft vascularization from surrounding tissues was detrimental for motor recovery. The processed nerve allografts used in this study showed similar functional motor recovery compared with that of the autograft.

The amnion muscle combined graft (AMCG) conduits: a new alternative in the repair of wide substance loss of peripheral nerves

The use of autologous sural nerve grafts is still the current gold standard for the repair of peripheral nerve injuries with wide substance losses, but with a poor rate of functional recovery after repair of mixed and motor nerves, a limited donor nerve supply, and morbidity of donor site. At present, tubulization through the muscle vein combined graft, is a viable alternative to the nerve autografts and certainly is a matter of tissue engineering still open to continuous development, although this technique is currently limited to a critical gap of 3 cm with less favorable results for motor function recovery. In this report, we present a completely new tubulization method, the amnion muscle combined graft (AMCG) technique, that consists in the combination of the human amniotic membrane hollow conduit with autologous skeletal muscle fragments for repairing the substance loss of peripheral nerves and recover both sensory and motor functions. In a series of five patients with loss of substance of the median nerve ranging 3-5 cm at the wrist, excellent results graded as S4 in two cases, S3+ in two cases, and S3 in one case; M4 in four cases and M3 in one case were achieved. No iatrogenic damage due to withdrawal of a healthy nerve from donor site was observed. This technique allows to repair extensive loss of substance up to 5 cm with a good sensory and motor recovery. The AMCG thus may be considered a reasonable alternative to traditional nerve autograft in selected clinical conditions.

Biocompatibility and Efficacy of Five-Channel and Eight-Channel Crosslinked Urethane-Doped Polyester Elastomers (CUPEs) as Nerve Guidance Conduit for Reconstruction of Segmental Peripheral Nerve Defect Using Rat Model

Introduction: Peripheral nerve injury is common in clinical practice. Nerve defect is a challenging scenario. The current gold standard of managing a nerve defect is autologous nerve graft. However, due to the selection of nerve graft and donor site morbidity, artificial nerve conduits are gaining popularity. However, there are drawbacks of single hollow conduit such as lack of internal support to prevent conduit collapse and inability so as to recreate the proper native spatial arrangement of cells and extracellular matrix within the conduit. In this study, the biocompatibility and efficacy of five-channel and eight-channel Crosslinked Urethane-doped Polyester Elastomers (CUPEs) as nerve guidance conduit will be evaluated through a rat model with reconstruction of segmental peripheral nerve defect. Material and Method: Eighteen adult Sprague-Dawley rats were used. They were randomly allocated to three groups: autograft group, five-channel conduit group and eight-channel conduit group with each consisted of six rats. A 10mm nerve defects were created at the right sciatic nerve. They were bridged with reverse autograft, 5-channel conduit and 8-channel conduit. After eight weeks the rats were euthanized and the reconstructed nerves were harvested for histomorphometric analysis. Result: All conduits showed regenerated nerve tissue inside. There was no collapse of the conduits. There were no severe tissue reaction or scarring near the reconstructed nerve. No neuroma was formed. Histomorphometric analysis showed nerve regeneration was enhanced with increasing number of channels inside conduit. There was overall drop in fiber density between proximal and distal segment among all groups. Conclusion: CUPE nerve guidance conduit is biocompatible and shows good nerve regeneration in reconstructing nerve defect.

The behavior of neuronal cells on tendon-derived collagen sheets as potential substrates for nerve regeneration

Peripheral nervous system injuries result in a decreased quality of life, and generally require surgical intervention for repair. Currently, the gold standard of nerve autografting, based on the use of host tissue such as sensory nerves is suboptimal as it results in donor-site loss of function and requires a secondary surgery. Nerve guidance conduits fabricated from natural polymers such as collagen are a common alternative to bridge nerve defects. In the present work, tendon sections derived through a process named bioskiving were studied for their potential for use as a substrate to fabricate nerve guidance conduits. We show that cells such as rat Schwann cells adhere, proliferate, and align along the fibrous tendon substrate which has been shown to result in a more mature phenotype. Additionally we demonstrate that chick dorsal root ganglia explants cultured on the tendon grow to similar lengths compared to dorsal root ganglia cultured on collagen gels, but also grow in a more oriented manner on the tendon sections. These results show that tendon sections produced through bioskiving can support directional nerve growth and may be of use as a substrate for the fabrication of nerve guidance conduits.

Return of motor function after repair of a 3-cm gap in a rabbit peroneal nerve: a comparison of autograft, collagen conduit, and conduit filled with collagen-GAG matrix

BACKGROUND

The purpose of this study was to evaluate the motor nerve recovery in a rabbit model after repair of a 3-cm gap in the peroneal nerve with a conduit filled with a collagen-GAG (glycosaminoglycan) matrix and compare the results with those after reconstruction with an autograft or an empty collagen conduit.

METHODS

Forty-two male New Zealand rabbits were divided into three experimental groups. In each group, a unilateral 3-cm peroneal nerve defect was repaired with a nerve autograft, an empty collagen conduit, or a conduit filled with a collagen-GAG matrix. At six months, nerve regeneration was evaluated on the basis of the compound muscle action potentials, maximum isometric tetanic force, and wet muscle weight of the tibialis anterior muscle as well as nerve histomorphometry.

RESULTS

The autograft group had significantly better motor recovery than the conduit groups. The empty collagen conduits and conduits filled with the collagen-GAG matrix led to results that were similar to each other.

CONCLUSIONS

On the basis of this rabbit model, autologous nerve grafting remains the gold standard in the reconstruction of 3-cm segmental motor nerve defects.

CLINICAL RELEVANCE

Segmental motor nerve defects should be reconstructed with autograft nerves. The use of a collagen conduit filled with a collagen-GAG matrix for motor nerve reconstruction should be limited until additional animal studies are performed.

Traumatic injuries of peripheral nerves: a review with emphasis on surgical indication

Traumatic peripheral nerve injury is a dramatic condition present in many of the injuries to the upper and lower extremities. An understanding of its physiopathology and selection of a suitable time for surgery are necessary for proper treatment of this challenging disorder. This article reviews the physiopathology of traumatic peripheral nerve injury, considers the most used classification, and discusses the main aspects of surgical timing and treatment of such a condition.

Transplantation of Schwann cells in a collagen tube for the repair of large, segmental peripheral nerve defects in rats

Object

Segmental nerve defects pose a daunting clinical challenge, as peripheral nerve injury studies have established that there is a critical nerve gap length for which the distance cannot be successfully bridged with current techniques. Construction of a neural prosthesis filled with Schwann cells (SCs) could provide an alternative treatment to successfully repair these long segmental gaps in the peripheral nervous system. The object of this study was to evaluate the ability of autologous SCs to increase the length at which segmental nerve defects can be bridged using a collagen tube.

Methods

The authors studied the use of absorbable collagen conduits in combination with autologous SCs (200,000 cells/μl) to promote axonal growth across a critical size defect (13 mm) in the sciatic nerve of male Fischer rats. Control groups were treated with serum only–filled conduits of reversed sciatic nerve autografts. Animals were assessed for survival of the transplanted SCs as well as the quantity of myelinated axons in the proximal, middle, and distal portions of the channel.

Results

Schwann cell survival was confirmed at 4 and 16 weeks postsurgery by the presence of prelabeled green fluorescent protein–positive SCs within the regenerated cable. The addition of SCs to the nerve guide significantly enhanced the regeneration of myelinated axons from the nerve stump into the proximal (p < 0.001) and middle points (p < 0.01) of the tube at 4 weeks. The regeneration of myelinated axons at 16 weeks was significantly enhanced throughout the entire length of the nerve guide (p < 0.001) as compared with their number in a serum–only filled tube and was similar in number compared with the reversed autograft. Autotomy scores were significantly lower in the animals whose sciatic nerve was repaired with a collagen conduit either without (p < 0.01) or with SCs (p < 0.001) when compared with a reversed autograft.

Conclusions

The technique of adding SCs to a guidance channel significantly enhanced the gap distance that can be repaired after peripheral nerve injury with long segmental defects and holds promise in humans. Most importantly, this study represents some of the first essential steps in bringing autologous SC-based therapies to the domain of peripheral nerve injuries with long segmental defects.

Sensory recovery outcome after digital nerve repair in relation to different reconstructive techniques: meta-analysis and systematic review

Good clinical outcome after digital nerve repair is highly relevant for proper hand function and has a significant socioeconomic impact. However, level of evidence for competing surgical techniques is low. The aim is to summarize and compare the outcomes of digital nerve repair with different methods (end-to-end and end-to-side coaptations, nerve grafts, artificial conduit-, vein-, muscle, and muscle-in-vein reconstructions, and replantations) to provide an aid for choosing an individual technique of nerve reconstruction and to create reference values of standard repair for nonrandomized clinical studies. 87 publications including 2,997 nerve repairs were suitable for a precise evaluation. For digital nerve repairs there was practically no particular technique superior to another. Only end-to-side coaptation had an inferior two-point discrimination in comparison to end-to-end coaptation or nerve grafting. Furthermore, this meta-analysis showed that youth was associated with an improved sensory recovery outcome in patients who underwent digital replantation. For end-to-end coaptations, recent publications had significantly better sensory recovery outcomes than older ones. Given minor differences in outcome, the main criteria in choosing an adequate surgical technique should be gap length and donor site morbidity caused by graft material harvesting. Our clinical experience was used to provide a decision tree for digital nerve repair.

New Synthetic Prosthesis for Peripheral Nerve Injuries

Introduction. Even the most modern technology has failed to induce satisfactory functional regeneration of traumatically severed peripheral nerves. Delayed neural regeneration and in consequence, slower neural conduction seriously limit muscle function in the area supplied by the injured nerve. This study aimed to compare a new nerve coaptation system involving an innovative prosthesis with the classical clinical method of sutured nerve coaptation. Besides the time and degree of nerve regeneration, the influence of electrostimulation was also tested. Methods. The sciatic nerve was severed in 14 female Göttingen minipigs with an average weight of 40.4 kg. The animals were randomized into 2 groups: One group received the new prosthesis and the other underwent microsurgical coaptation. In each group, according to the randomization a part of the animals received postoperative electrostimulation. Postoperative monitoring and the stimulation schedule covered a period of 9 months, during which axonal budding was evaluated monthly. Results. The data from the pilot study indicate that results with the nerve prosthesis were comparable with those of conventional coaptation. Conclusion. The results indicate that implantation of the nerve prosthesis allows for good and effective neural regeneration. This new and simple treatment option for peripheral nerve injuries can be performed in any hospital with surgical facilities as it does not involve the demanding microsurgical suture technique that can only be performed in specialized centers.

End-to-side neurorrhaphy using an electrospun PCL/collagen nerve conduit for complex peripheral motor nerve regeneration

In cases of complex neuromuscular defects, finding the proximal stump of a transected nerve in order to restore innervation to damaged muscle is often impossible. In this study we investigated whether a neighboring uninjured nerve could serve as a source of innervation of denervated damaged muscle through a biomaterial-based nerve conduit while preserving the uninjured nerve function. Tubular nerve conduits were fabricated by electrospinning a polymer blend consisting of poly(ε-caprolactone) (PCL) and type I collagen. Using a rat model of common peroneal injury, the proximal end of the nerve conduit was connected to the side of the adjacent uninjured tibial branch (TB) of the sciatic nerve after partial axotomy, and the distal end of the conduit was connected to the distal stump of the common peroneal nerve (CPN). The axonal continuity recovered through the nerve conduit at 8 weeks after surgery. Recovery of denervated muscle function was achieved, and simultaneously, the donor muscle, which was innervated by the axotomized TB also recovered at 20 weeks after surgery. Therefore, this end-to-side neurorrhaphy (ETS) technique using the electrospun PCL/collagen conduit appears to be clinically feasible and would be a useful alternative in instances where autologous nerve grafts or an adequate proximal nerve stump is unavailable.

Neural stem cells enhance nerve regeneration after sciatic nerve injury in rats

With the development of tissue engineering and the shortage of autologous nerve grafts in nerve reconstruction, cell transplantation in a conduit is an alternative strategy to improve nerve regeneration. The present study evaluated the effects and mechanism of brain-derived neural stem cells (NSCs) on sciatic nerve injury in rats. At the transection of the sciatic nerve, a 10-mm gap between the nerve stumps was bridged with a silicon conduit filled with 5 × 10(5) NSCs. In control experiments, the conduit was filled with nerve growth factor (NGF) or normal saline (NS). The functional and morphological properties of regenerated nerves were investigated, and expression of hepatocyte growth factor (HGF) and NGF was measured. One week later, there was no connection through the conduit. Four or eight weeks later, fibrous connections were evident between the proximal and distal segments. Motor function was revealed by measurement of the sciatic functional index (SFI) and sciatic nerve conduction velocity (NCV). Functional recovery in the NSC and NGF groups was significantly more advanced than that in the NS group. NSCs showed significant improvement in axon myelination of the regenerated nerves. Expression of NGF and HGF in the injured sciatic nerve was significantly lower in the NS group than in the NSCs and NGF groups. These results and other advantages of NSCs, such as ease of harvest and relative abundance, suggest that NSCs could be used clinically to enhance peripheral nerve repair.

Neurological recovery across a 12-cm-long ulnar nerve gap repaired 3.25 years post trauma: case report

BACKGROUND AND IMPORTANCE

The standard clinical technique for repairing peripheral nerve gaps is the use of autologous sensory nerve grafts. The present study tested whether a collagen tube filled with autologous platelet-rich fibrin could induce sensory and motor recovery across a 12-cm nerve gap repaired 3.25 years post trauma, and reduce or eliminate neuropathic pain.

CLINICAL PRESENTATION

Two years postrepair, good ring and small finger motor function had developed that could generate 1 kg of force, and topographically correct 2-point discrimination and sensitivity to vibration in the small and ring finger and proximal but not distal wrist had developed. The patient's excruciating neuropathic pain was reduced to tolerable, and he avoided the indicated extremity amputation. The 12-cm-long nerve gap was bridged with a collagen tube filled with autologous platelet-rich fibrin.

CONCLUSION

We demonstrate that a conduit filled with platelet-rich fibrin can induce limited, but appropriate, sensory and motor recovery across a 12-cm nerve gap repaired 3.25 years post trauma, without sacrificing a sensory nerve, can reduce existing excruciating neuropathic pain to tolerable, and allow avoidance of an indicated upper-extremity amputation. We believe the technique can be improved to induce more extensive and reliable neurological recovery.

Nerve-muscle-endplate band grafting: a new technique for muscle reinnervation

BACKGROUND

Because currently existing reinnervation methods result in poor functional recovery, there is a great need to develop new treatment strategies.

OBJECTIVE

To investigate the efficacy of our recently developed nerve-muscle-endplate band grafting (NMEG) technique for muscle reinnervation.

METHODS

Twenty-five adult rats were used. Sternohyoid (SH) and sternomastoid (SM) muscles served as donor and recipient muscle, respectively. Neural organization of the SH and SM muscles and surgical feasibility of the NMEG technique were determined. An NMEG contained a muscle block, a nerve branch with nerve terminals, and a motor endplate band with numerous neuromuscular junctions. After a 3-month recovery period, the degree of functional recovery was evaluated with a maximal tetanic force measurement. Retrograde horseradish peroxidase tracing was used to track the origin of the motor innervation of the reinnervated muscles. The reinnervated muscles were examined morphohistologically and immunohistochemically to assess the extent of axonal regeneration.

RESULTS

Nerve supply patterns and locations of the motor endplate bands in the SH and SM muscles were documented. The results demonstrated that the reinnervated SM muscles gained motor control from the SH motoneurons. The NMEG technique yielded extensive axonal regeneration and significant recovery of SM muscle force-generating capacity (67% of control). The mean wet weight of the NMEG-reinnervated muscles (87% of control) was greater than that of the denervated SM muscles (36% of control).

CONCLUSION

The NMEG technique resulted in successful muscle reinnervation and functional recovery. This technique holds promise in the treatment of muscle paralysis.

Peripheral neural sheath tumors (PNST)--what a radiologist should know

Peripheral neural sheath tumors (PNST) are rare and the common goal of management focuses on eliminating pain and maximizing function of the affected nerve. Therefore preoperative assessment of the specific morphological behaviour of such tumors regarding the nerves internal architecture is of utmost importance. PNSTs may affect one or more fascicles of a peripheral nerve resulting in a significant functional loss after resection and the necessity of functional reconstruction in one step. Enhancement of preoperative information should also address the biological behaviour of the tumor regarding its dignity and the resulting implications on amount of radical resection, additional treatment and prognosis. Since high-resolution techniques promise more and more detail resolution in many fields of imaging, delineation of intra- and extraneural processes as well as biological informations shall lead towards a well prepared and foreseeable image-guided treatment of PNSTs.

Median nerve reconstruction after entrapment in the elbow

Median nerve entrapment in the elbow is a known but rare complication of pediatric elbow dislocations. It is classified on the anatomical basis of entrapment. Due to a variety of factors, it is often diagnosed late. Because of this, substantial injury occurs to the nerve, requiring some form of restorative surgery in addition to release from the joint. Such nerve injury has been treated in a variety of ways including neurolysis, end-to-end anastomosis and nerve grafting. To date, there has been no conclusive evidence in the literature that one method should be preferred over another. A case of median nerve entrapment that was treated with sural nerve grafting is presented. In a review of the literature, previous treatment of such cases is discussed and compared.

Non-surgical therapies for peripheral nerve injury

BACKGROUND

Non-surgical approaches have been developed to enhance nerve recovery, which are complementary to surgery and are an adjunct to the reinnervation process.

SOURCES OF DATA

A search of PubMed, Medline, CINAHL, DH data and Embase databases was performed using the keywords 'peripheral nerve injury' and 'treatment'.

AREAS OF CONTROVERSY

Most of the conservative therapies are focused to control neuropathic pain after nerve tissue damage. Only physical therapy modalities have been studied in humans and their effectiveness is not proved.

GROWING POINTS

Many modalities have been experimented with to promote nerve healing and restore function in animal models and in vitro studies. Despite this, none have been actually translated into clinical practice.

AREAS TIMELY FOR DEVELOPING RESEARCH

The hypotheses proved in animals and in vitro should be translated to human clinical practice.

Transplantation of bone-marrow-derived cells into a nerve guide resulted in transdifferentiation into Schwann cells and effective regeneration of transected mouse sciatic nerve

Peripheral nerves possess the capacity of self-regeneration after traumatic injury. Nevertheless, the functional outcome after peripheral-nerve regeneration is often poor, especially if the nerve injuries occur far from their targets. Aiming to optimize axon regeneration, we grafted bone-marrow-derived cells (BMDCs) into a collagen-tube nerve guide after transection of the mouse sciatic nerve. The control group received only the culture medium. Motor function was tested at 2, 4, and 6 weeks after surgery, using the sciatic functional index (SFI), and showed that functional recovery was significantly improved in animals that received the cell grafts. After 6 weeks, the mice were anesthetized, perfused transcardially, and the sciatic nerves were dissected and processed for transmission electron microscopy and light microscopy. The proximal and distal segments of the nerves were compared, to address the question of improvement in growth rate; the results revealed a maintenance and increase of nerve regeneration for both myelinated and non-myelinated fibers in distal segments of the experimental group. Also, quantitative analysis of the distal region of the regenerating nerves showed that the numbers of myelinated fibers, Schwann cells (SCs) and g-ratio were significantly increased in the experimental group compared to the control group. The transdifferentiation of BMDCs into Schwann cells was confirmed by double labeling with S100/and Hoechst staining. Our data suggest that BMDCs transplanted into a nerve guide can differentiate into SCs, and improve the growth rate of nerve fibers and motor function in a transected sciatic-nerve model.

Modern surgical management of peripheral nerve gap

The management of peripheral nerve injury requires a thorough understanding of the complex physiology of nerve regeneration. The ability to perform surgery under magnification has improved our understanding of the anatomy of the peripheral nerves. However, the level of functional improvement that can be expected following peripheral nerve injury has plateaued. Advancements in the field of tissue engineering have led to an exciting complement of commercially available products that can be used to bridge peripheral nerve gaps. However, the quest for enhanced options is ongoing. This article provides a review of the current treatment options available following peripheral nerve injury, a summary of the published studies using commercially available nerve conduits and nerve allografts in humans and the emerging hopes for the next generation of nerve conduits with the advancement of nanotechnology.

Effect of upper extremity nerve damage on activity participation, pain, depression, and quality of life

PURPOSE

To explore the relationship between upper extremity nerve damage and activity participation, pain, depression, and perceived quality of life.

METHODS

A total of 49 patients with upper extremity nerve damage completed standardized measures of activity participation, pain, depression, and quality of life. We analyzed scores for all subjects and for 2 diagnostic groups: patients with compressive neuropathy and patients with nerve injury (laceration, tumor, and brachial plexus injury), and explored predictors of overall quality of life.

RESULTS

Participants had given up 21% of their previous daily activities; greater activity loss was reported in patients with nerve injury. Pain was moderate and 39% had signs of clinical depression. Physical and psychological quality of life ratings were below the norms. Activity loss was strongly associated with higher levels of depression and lower physical and psychological quality of life. Higher depression scores correlated strongly with lower overall quality of life. Greater pain correlated moderately with higher depression scores and weakly with quality of life; no statistical relationship was found between pain and physical quality of life. Activity participation and depression predicted 61% of the variance in overall quality of life in patients with nerve damage.

CONCLUSIONS

The results of this study suggest that hand surgeons and therapists caring for patients with nerve compression and nerve injury should discuss strategies to improve activity participation, and decrease pain and depression, to improve overall effect on quality of life throughout the recovery process. Depression screening and referral when indicated should be included in the overall treatment plan for patients with upper extremity nerve damage.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.