A decellularized nerve matrix scaffold inhibits neuroma formation in the stumps of transected peripheral nerve after peripheral nerve injury.

Traumatic painful neuroma is an intractable clinical disease characterized by improper extracellular matrix (ECM) deposition around the injury site. Studies have shown that the microstructure of natural nerves provides a suitable microenvironment for the nerve end to avoid abnormal hyperplasia and neuroma formation. In this study, we used a decellularized nerve matrix scaffold (DNM-S) to prevent against the formation of painful neuroma after sciatic nerve transection in rats. Our results showed that the DNM-S effectively reduced abnormal deposition of ECM, guided the regeneration and orderly arrangement of axon, and decreased the density of regenerated axons. The epineurium-perilemma barrier prevented the invasion of vascular muscular scar tissue, greatly reduced the invasion of α-smooth muscle actin-positive myofibroblasts into nerve stumps, effectively inhibited scar formation, which guided nerve stumps to gradually transform into a benign tissue and reduced pain and autotomy behaviors in animals. These findings suggest that DNM-S-optimized neuroma microenvironment by ECM remodeling may be a promising strategy to prevent painful traumatic neuromas.

Endometriosis of the sciatic nerve masquerading as lumbar spondylosis in a 40-year-old Chinese woman.

A 40-year-old Chinese woman presented with a 4-year history of lower back pain and left lower leg sciatica. The patient had previously tried different modalities of treatments, including massage, acupuncture, ultrasound, alternative Bowen therapy and nonsteroidal anti-inflammatory drugs (NSAIDs), all of which only provided temporary relief. On presentation to a tertiary hospital, careful and comprehensive history taking found that the sciatica pattern of pain always coincided with menstruation. An MRI identified a thickened left sciatic nerve, with surgery confirming sciatic nerve endometriosis. The case highlights the importance of comprehensive history taking in accurately diagnosing a rare aetiology of sciatica with subsequent prompt surgical intervention to avoid severe disability as well as follow-up treatment to prevent recurrence.

Use of personal protective equipment against coronavirus disease 2019 by healthcare professionals in Wuhan, China: cross sectional study.

OBJECTIVE: To examine the protective effects of appropriate personal protective equipment for frontline healthcare professionals who provided care for patients with coronavirus disease 2019 (covid-19). DESIGN: Cross sectional study. SETTING: Four hospitals in Wuhan, China. PARTICIPANTS: 420 healthcare professionals (116 doctors and 304 nurses) who were deployed to Wuhan by two affiliated hospitals of Sun Yat-sen University and Nanfang Hospital of Southern Medical University for 6-8 weeks from 24 January to 7 April 2020. These study participants were provided with appropriate personal protective equipment to deliver healthcare to patients admitted to hospital with covid-19 and were involved in aerosol generating procedures. 77 healthcare professionals with no exposure history to covid-19 and 80 patients who had recovered from covid-19 were recruited to verify the accuracy of antibody testing. MAIN OUTCOME MEASURES: Covid-19 related symptoms (fever, cough, and dyspnoea) and evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, defined as a positive test for virus specific nucleic acids in nasopharyngeal swabs, or a positive test for IgM or IgG antibodies in the serum samples. RESULTS: The average age of study participants was 35.8 years and 68.1% (286/420) were women. These study participants worked 4-6 hour shifts for an average of 5.4 days a week; they worked an average of 16.2 hours each week in intensive care units. All 420 study participants had direct contact with patients with covid-19 and performed at least one aerosol generating procedure. During the deployment period in Wuhan, none of the study participants reported covid-19 related symptoms. When the participants returned home, they all tested negative for SARS-CoV-2 specific nucleic acids and IgM or IgG antibodies (95% confidence interval 0.0 to 0.7%). CONCLUSION: Before a safe and effective vaccine becomes available, healthcare professionals remain susceptible to covid-19. Despite being at high risk of exposure, study participants were appropriately protected and did not contract infection or develop protective immunity against SARS-CoV-2. Healthcare systems must give priority to the procurement and distribution of personal protective equipment, and provide adequate training to healthcare professionals in its use.

Covering the proximal nerve stump with chondroitin sulfate proteoglycans prevents traumatic painful neuroma formation by blocking axon regeneration after neurotomy in Sprague Dawley rats.

OBJECTIVE: Neuropathic pain caused by traumatic neuromas is an extremely intractable clinical problem. Disorderly scar tissue accumulation and irregular and immature axon regeneration around the injury site mainly contribute to traumatic painful neuroma formation. Therefore, successfully preventing traumatic painful neuroma formation requires the effective inhibition of irregular axon regeneration and disorderly accumulation of scar tissue. Considering that chondroitin sulfate proteoglycans (CSPGs) can act on the growth cone and effectively inhibit axon regeneration, the authors designed and manufactured a CSPG-gelatin blocker to regulate the CSPGs' spatial distribution artificially and applied it in a rat model after sciatic nerve neurectomy to evaluate its effects in preventing traumatic painful neuroma formation. METHODS: Sixty female Sprague Dawley rats were randomly divided into three groups (positive group: no covering; blank group: covering with gelatin blocker; and CSPG group: covering with the CSPG-gelatin blocker). Pain-related factors were evaluated 2 and 8 weeks postoperatively (n = 30). Neuroma growth, autotomy behavior, and histological features of the neuromas were assessed 8 weeks postoperatively (n = 30). RESULTS: Eight weeks postoperatively, typical bulb-shaped neuromas did not form in the CSPG group, and autotomy behavior was obviously better in the CSPG group (p < 0.01) than in the other two groups. Also, in the CSPG group the regenerated axons showed a lower density and more regular and improved myelination (p < 0.01). Additionally, the distribution and density of collagenous fibers and the expression of α-smooth muscle actin were significantly lower in the CSPG group than in the positive group (p < 0.01). Regarding pain-related factors, c-fos, substance P, interleukin (IL)-17, and IL-1ß levels were significantly lower in the CSPG group than those in the positive and blank groups 2 weeks postoperatively (p < 0.05), while substance P and IL-17 remained lower in the CSPG group 8 weeks postoperatively (p < 0.05). CONCLUSIONS: The authors found that CSPGs loaded in a gelatin blocker can prevent traumatic neuroma formation and effectively relieve pain symptoms after sciatic nerve neurotomy by blocking irregular axon regeneration and disorderly collagenous fiber accumulation in the proximal nerve stump. These results indicate that covering the proximal nerve stump with CSPGs may be a new and promising strategy to prevent traumatic painful neuroma formation in the clinical setting.

Application of custom anatomy-based nerve conduits on rabbit sciatic nerve defects: in vitro and in vivo evaluations.

The intermingling of regenerated nerve fibers inside nerve grafts is the main reason for mismatched nerve fibers. This is one of the key factors affecting limb function recovery after nerve injury. Previous research has shown that the accuracy of axon regeneration can be improved by a bionic structural implant. To this aim, iodine and freeze-drying high-resolution micro-computed tomography was performed to visualize the 3D topography of the New Zealand rabbit sciatic nerve (25 mm). A series of 1-, 2-, 3-, and 4-custom anatomy-based nerve conduits (CANCs) were fabricated based on the anatomical structure of the nerve fascicle. The match index, luminal surface, and mechanical properties of CANCs were evaluated before implanting in a 10-mm gap of the sciatic nerve. Recovery was evaluated by histomorphometric analyses, electrophysiological study, gastrocnemius muscle weight recovery ratio, and behavioral assessments at 12 and 24 weeks postoperatively. The accuracy of nerve regeneration was determined by changes in fluorescence-labeled profile number during simultaneous retrograde tracing. Our results showed that the optimal preprocessing condition for high-resolution micro-computed tomography visualization was treatment of the sciatic nerve with 40% Lugol's solution for 3 days followed by lyophilization for 2 days. In vitro experiments demonstrated that the match index was highest in the 3-CANC group, followed by the 2-, 1-, and 4-CANC groups. The luminal surface was lowest in the 1-CANC group. Mechanical properties (transverse compressive and bending properties) were higher in the 3- and 4-CANC groups than in the 1-CANC group. In vivo experiments demonstrated that the recovery (morphology of regenerated fibers, compound muscle action potential, gastrocnemius muscle weight recovery ratio, pain-related autotomy behaviors, and range of motion) in the 3-CANC group was superior to the other CANC groups, and achieved the same therapeutic effect as the autograft. The simultaneous retrograde tracing results showed that the percentages of double-labeled profiles of the 2-, 3-, and 4-CANC groups were comparatively lower than that of the 1-CANC group, which indicates that regenerated nerve fascicles were less intermingled in the 2-, 3-, and 4-CANC groups. These findings demonstrate that the visualization of the rabbit sciatic nerve can be achieved by iodine and freeze-drying high-resolution micro-computed tomography, and that this method can be used to design CANCs with different channels that are based on the anatomical structure of the nerve. Compared with the 1-CANC, 3-CANC had a higher match index and luminal surface, and improved the accuracy of nerve regeneration by limiting the intermingling of the regenerated fascicles. All procedures were approved by the Animal Care and Use Committee, Xinjiang Medical University, China on April 4, 2017 (ethics approval No. IACUC20170315-02).

Customized Scaffold Design Based on Natural Peripheral Nerve Fascicle Characteristics for Biofabrication in Tissue Regeneration.

OBJECTIVE: The use of a biofabrication nerve scaffold, which mimics the nerve microstructure, as an alternative for autologous nerve transplantation is a promising strategy for treating peripheral nerve defects. This study aimed to design a customized biofabrication scaffold model with the characteristics of human peripheral nerve fascicles. METHODS: We used Micro-MRI technique to obtain different nerve fascicles. A full-length 28 cm tibial nerve specimen was obtained and was divided into 14 two-centimetre nerve segments. 3D models of the nerve fascicles were obtained by three-dimensional reconstruction after image segmentation. The central line of the nerve fascicles was fitted, and the aggregation of nerve fascicles was analysed quantitatively. The nerve scaffold was designed by simulating the clinical nerve defect and extracting information from the acquired nerve fascicle data; the scaffold design was displayed by 3D printing to verify the accuracy of the model. RESULT: The microstructure of the sciatic nerve, tibial nerve, and common peroneal nerve in the nerve fascicles could be obtained by three-dimensional reconstruction. The number of cross fusions of tibial nerve fascicles from proximal end to distal end decreased gradually. By designing the nerve graft in accordance with the microstructure of the nerve fascicles, the 3D printed model demonstrated that the two ends of the nerve defect can be well matched. CONCLUSION: The microstructure of the nerve fascicles is complicated and changeable, and the spatial position of each nerve fascicle and the long segment of the nerve fascicle aggregation show great changes at different levels. Under the premise of the stability of the existing imaging techniques, a large number of scanning nerve samples can be used to set up a three-dimensional database of the peripheral nerve fascicle microstructure, integrating the gross imaging information, and provide a template for the design of the downstream nerve graft model.

Tissue engineering for the repair of peripheral nerve injury.

Peripheral nerve injury is a common clinical problem and affects the quality of life of patients. Traditional restoration methods are not satisfactory. Researchers increasingly focus on the field of tissue engineering. The three key points in establishing a tissue engineering material are the biological scaffold material, the seed cells and various growth factors. Understanding the type of nerve injury, the construction of scaffold and the process of repair are necessary to solve peripheral nerve injury and promote its regeneration. This review describes the categories of peripheral nerve injury, fundamental research of peripheral nervous tissue engineering and clinical research on peripheral nerve scaffold material, and paves a way for related research and the use of conduits in clinical practice.

A rapid micro-magnetic resonance imaging scanning for three-dimensional reconstruction of peripheral nerve fascicles.

The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging (Micro-MRI), an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by 1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions (Mannerist Solution/GD-DTPA contrast agent, distilled water) were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent (Mannerist Solution/GD-DTPA) and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.

Various changes in cryopreserved acellular nerve allografts at -80°C.

The experimental design evaluated histological, mechanical, and biological properties of allogeneic decellularized nerves after cryopreservation in a multi-angle, multi-directional manner to provide evidence for long-term preservation. Acellular nerve allografts from human and rats were cryopreserved in a cryoprotectant (10% fetal bovine serum, 10% dimethyl sulfoxide, and 5% sucrose in RPMI1640 medium) at -80°C for 1 year, followed by thawing at 40°C or 37°C for 8 minutes. The breaking force of acellular nerve allografts was measured using a tensile test. Cell survival was determined using L-929 cell suspensions. Acellular nerve allografts were transplanted into a rat model with loss of a 15-mm segment of the left sciatic nerve. Immunohistochemistry staining was used to measure neurofilament 200 expression. Hematoxylin-eosin staining was utilized to detect relative muscle area in gastrocnemius muscle. Electron microscopy was applied to observe changes in allograft ultrastructure. There was no obvious change in morphological appearance or ultrastructure, breaking force, or cytotoxicity of human acellular nerve allografts after cryopreservation at -80°C. Moreover, there was no remarkable change in neurofilament 200 expression, myelin sheath thickness, or muscle atrophy when fresh or cryopreserved rat acellular nerve allografts were applied to repair nerve injury in rats. These results suggest that cryopreservation can greatly extend the storage duration of acellular nerve tissue allografts without concomitant alteration of the physiochemical and biological properties of the engineered tissue to be used for transplantation.

Spatial distribution affects the role of CSPGs in nerve regeneration via the actin filament-mediated pathway.

CSPGs are components of the extracellular matrix in the nervous system, where they serve as cues for axon guidance during development. After a peripheral nerve injury, CSPGs switch roles and become axon inhibitors and become diffusely distributed at the injury site. To investigate whether the spatial distribution of CSPGs affects their role, we combined in vitro DRG cultures with CSPG stripe or coverage assays to simulate the effect of a patterned substrate or dispersive distribution of CSPGs on growing neurites. We observed neurite steering at linear CSPG interfaces and neurite inhibition when diffused CSPGs covered the distal but not the proximal segment of the neurite. The repellent and inhibitory effects of CSPGs on neurite outgrowth were associated with the disappearance of focal actin filaments on growth cones. The application of an actin polymerization inducer, jasplakinolide, allowed neurites to break through the CSPG boundary and grow on CSPG-coated surfaces. The results of our study collectively reveal a novel mechanism that explains how the spatial distribution of CSPGs determines whether they act as a cue for axon guidance or as an axon-inhibiting factor. Increasing our understanding of this issue may promote the development of novel therapeutic strategies that regulate the spatial distributions of CSPGs to use them as an axon guidance cue.

Emergency repair of upper extremity large soft tissue and vascular injuries with flow-through anterolateral thigh free flaps.

BACKGROUND/OBJECTIVES: Complex extremity trauma commonly involves both soft tissue and vascular injuries. Traditional two-stage surgical repair may delay rehabilitation and functional recovery, as well as increase the risk of infections. We report a single-stage reconstructive surgical method that repairs soft tissue defects and vascular injuries with flow-through free flaps to improve functional outcomes. METHODS: Between March 2010 and December 2016 in our hospital, 5 patients with severe upper extremity trauma received single-stage reconstructive surgery, in which a flow-through anterolateral thigh free flap was applied to repair soft tissue defects and vascular injuries simultaneously. Cases of injured artery were reconstructed with the distal trunk of the descending branch of the lateral circumflex femoral artery. A segment of adjacent vein was used if there was a second artery injury. Patients were followed to evaluate their functional recoveries, and received computed tomography angiography examinations to assess peripheral circulation. RESULTS: Two patients had post-operative thumb necrosis; one required amputation, and the other was healed after debridement and abdominal pedicle flap repair. The other 3 patients had no major complications (infection, necrosis) to the recipient or donor sites after surgery. All the patients had achieved satisfactory functional recovery by the end of the follow-up period. Computed tomography angiography showed adequate circulation in the peripheral vessels. CONCLUSIONS: The success of these cases shows that one-step reconstructive surgery with flow-through anterolateral thigh free flaps can be a safe and effective treatment option for patients with complex upper extremity trauma with soft tissue defects and vascular injuries.

Diagnostic Value and Surgical Implications of the 3D DW-SSFP MRI On the Management of Patients with Brachial Plexus Injuries.

Three-dimensional diffusion-weighted steady-state free precession (3D DW-SSFP) of high-resolution magnetic resonance has emerged as a promising method to visualize the peripheral nerves. In this study, the application value of 3D DW-SSFP brachial plexus imaging in the diagnosis of brachial plexus injury (BPI) was investigated. 33 patients with BPI were prospectively examined using 3D DW-SSFP MR neurography (MRN) of brachial plexus. Results of 3D DW-SSFP MRN were compared with intraoperative findings and measurements of electromyogram (EMG) or somatosensory evoked potentials (SEP) for each injured nerve root. 3D DW-SSFP MRN of brachial plexus has enabled good visualization of the small components of the brachial plexus. The postganglionic section of the brachial plexus was clearly visible in 26 patients, while the preganglionic section of the brachial plexus was clearly visible in 22 patients. Pseudomeningoceles were commonly observed in 23 patients. Others finding of MRN of brachial plexus included spinal cord offset (in 16 patients) and spinal cord deformation (in 6 patients). As for the 3D DW-SSFP MRN diagnosis of preganglionic BPI, the sensitivity, the specificity and the accuracy were respectively 96.8%, 90.29%, and 94.18%. 3D DW-SSFP MRN of brachial plexus improve visualization of brachial plexus and benefit to determine the extent of injury.

Microanatomy of the Separable Length of the C7.

OBJECTIVE: The objective of this study was to provide anatomical data on modified contralateral C7 (cC7) nerve root transfers by dissecting and measuring the separable lengths of the C7 root, trunk, and divisions. MATERIALS AND METHODS: Fifteen adult cervicothoracic specimens were dissected and measured using Vernier calipers after exposing the brachial plexus. Measurements included the length of the C7 from the root to the trunk, the lengths of the C7 root-trunk-anterior division (and posterior division). The epineuria at the C7 root-division-cord junctions were opened until the internal nerve bundles fused together and could not be separated by microdissection. The lengths of the C7 root-trunk-anterior (and posterior) division were measured again after microdissection. The lengths of cC7 nerve of 20 patients with bracial plexus avulsion were measured using the former technique. RESULTS: The length of the C7 root-trunk was 45.87 SD 10.43 mm. Before separation, the lengths of the C7 root-trunk-anterior division and the root-trunk-posterior division were 61.14 SD 13.44 and 54.63 SD 11.35 mm, respectively; after separation, the lengths were 74.67 SD 12.86 and 68.73 SD 11.86 mm, respectively. The prolonged lengths were 13.15 SD 4.26 and 14.21 SD 6.98 mm, respectively. The prolonged lengths were significantly greater (p < 0.05). The prolonged length of C7 nerve clinically was anterior division, 15.30 SD 3.76 mm and posterior division, 11.10 SD 3.01 mm. CONCLUSION: The C7 division lengths can be prolonged by dissecting the epineuria at the division-cord junction of the C7 nerve root.

Calcium intake and hip fracture risk: a meta-analysis of prospective cohort studies.

It has been suggested that the amount of calcium intake may influence hip fracture incidence. However, the results of the researches in this regard are inconsistent. We performed this meta-analysis to estimate the association between calcium intake and hip fracture risk. Prospective cohort studies on calcium intake and hip fracture risk were identified by searching databases from the period 1960 to 2014. Results from individual studies were synthetically combined using STATA 11 software. The results indicated that a total of 8 prospective cohort studies were included in our meta-analysis, involving 2,435 cases and 267,759 participants. The combined relative risk (RR) of hip fracture for highest compared with lowest amount calcium intake was 0.97 (95% confidence interval [CI]: 0.89-1.07). Little evidence of publication bias was found. In conclusion, this meta-analysis provides evidence of no association between calcium intake and hip fracture risk. However, this finding is based on only a limited number of included studies.

A Meta-Analysis for Postoperative Complications in Tibial Plafond Fracture: Open Reduction and Internal Fixation Versus Limited Internal Fixation Combined With External Fixator.

The treatment of tibial plafond fractures is challenging to foot and ankle surgeons. Open reduction and internal fixation and limited internal fixation combined with an external fixator are 2 of the most commonly used methods of tibial plafond fracture repair. However, conclusions regarding the superior choice remain controversial. The present meta-analysis aimed to quantitatively compare the postoperative complications between open reduction and internal fixation and limited internal fixation combined with an external fixator for tibial plafond fractures. Nine studies with 498 fractures in 494 patients were included in the present study. The meta-analysis found no significant differences in bone healing complications (risk ratio [RR] 1.17, 95% confidence interval [CI] 0.68 to 2.01, p = .58], nonunion (RR 1.09, 95% CI 0.51 to 2.36, p = .82), malunion or delayed union (RR 1.24, 95% CI 0.57 to 2.69, p = .59), superficial (RR 1.56, 95% CI 0.43 to 5.61, p = .50) and deep (RR 1.89, 95% CI 0.62 to 5.80) infections, arthritis symptoms (RR 1.20, 95% CI 0.92 to 1.58, p = .18), or chronic osteomyelitis (RR 0.31, 95% CI 0.05 to 1.84, p = .20) between the 2 groups.

Human peripheral nerve-derived scaffold for tissue-engineered nerve grafts: histology and biocompatibility analysis.

Human acellular nerve grafts (ANGs) have been rarely used to construct tissue-engineered nerves compared to the animal-derived ANGs, and their potential clinical applications were relatively unknown. In this study, it was aimed to investigate the structure and components of a scaffold derived from human peripheral nerve and evaluate its biocompatibility. The human peripheral nerves were processed to prepare the scaffolds by chemical extraction. Light and electron microscopy were carried out to analyze scaffold structure and components. The analysis of cytotoxicity, hemolysis, and skin sensitization were performed to evaluate their biocompatibility. It was shown that Schwann cells and axons, identified by S-100 and neurofilament (NF) expression, were absent, and the scaffolds were cell-free and rich in collagen-I and laminin whose microarchitecture was similar to the fibrous framework of human peripheral nerves. It was revealed from biocompatibility tests that the scaffolds had very mild cytotoxicity and hemolysis, whereas skin sensitization was not observed. The constructed human peripheral nerve-derived scaffolds with well biocompatibility for clinical practice, which were cell-free and possess the microstructure and extracellular matrix (ECM) of a human nerve, might be an optimal scaffold for tissue-engineered nerve grafts in human.

Repairing large radial nerve defects by acellular nerve allografts seeded with autologous bone marrow stromal cells in a monkey model.

In this study, we aimed to evaluate the potential of tissue-engineered nerve grafts created from acellular allogenic nerve tissues combined with autologous bone marrow stromal cells (BMSCs) for repairing large peripheral nerve lesions. In a rhesus monkey model, a 2.5-cm-long gap was created in the radial nerve, followed by implantation of either autografts or acellular allografts seeded with autologous BMSCs, Schwann cells (SCs), or no cells. Five months after surgery nerve regeneration was assessed functionally, electrophysiologically, and histomorphometrically. Compared to non-cell-laden allografts, BMSC-laden allografts remarkably facilitated the recovery of the grasping functions of the animals. This functional improvement was coupled with increased nerve conduction velocities and peak amplitudes of compound motor action potentials, and greater axon growth, as well as higher target muscle weight. Moreover, the intensities of nerve regeneration in the BMSC-laden group were comparable to those achieved with SC-laden allografts and autografts. Our data highlight the potential of BMSC-seed allografts for the repair of long peripheral nerve lesions, and reveal comparable regeneration intensities achieved by BMSC-, and SC-laden allografts, as well as autografts. Given their wide availability, BMSCs may represent a promising cell source for tissue-engineered nerve grafts.

[The clinical value of high frequency ultrasound in diagnosis of peripheral nerve diseases].

OBJECTIVE: To evaluate the clinical value of high frequency ultrasound in diagnosing peripheral nerve diseases (PNDs). METHODS: From January 2003 to December 2006, 64 cases of PNDs were analyzed retrospectively. The ultrasound diagnosis was compared with the operative and pathological diagnosis. RESULTS: Based on the operative and histopathological results, in 38 patients with trauma or entrapment, 38 among 45 traumatic nerves were rightly diagnosed by ultrasound. The coincidence rate was 84.4%. In 26 patients with original peripheral nerve tumors (PNTs), including 20 neurilemmomas, 4 neurofibromas and 2 malignant neurilemmomas, 16 cases were diagnosed by ultrasound with a coincidence rate of 61.5%. The coincidence rates in limbs and trunk were 86.7% (13/15) and 27.3% (3/11) respectively. CONCLUSIONS: The study suggests that high frequency ultrasound can locate peripheral nerve trauma precisely, assess the impair degree correctly and provide useful information for clinic diagnosis. The high frequency ultrasound brings better diagnosis outcome in limbs nerve tumors than in trunk.

Location of collateral sprouting of donor nerve following end-to-side neurorrhaphy.

Various studies have demonstrated collateral regeneration of the donor nerve following end-to-side neurorrhaphy, but the location of collateral sprouting remains controversial. In a rat end-to-side neurorrhaphy model we isolated nerve fibers from the donor nerve at the neurorrhaphy site utilizing a micro-tease technique. We found that axons sprouted collaterally from a myelinated nerve fiber at the node of Ranvier. Based on this preliminary result we conclude that myelinated nerve fibers could sprout collateral branches at the node of Ranvier at an end-to-side neurorrhaphy site. These findings show that end-to-side neurorrhaphy may be an alternative for peripheral nerve repair.

Repair of extended peripheral nerve lesions in rhesus monkeys using acellular allogenic nerve grafts implanted with autologous mesenchymal stem cells.

Despite intensive efforts in the field of peripheral nerve injury and regeneration, it remains difficult in humans to achieve full functional recovery following extended peripheral nerve lesions. Optimizing repair of peripheral nerve injuries has been hindered by the lack of viable and reliable biologic or artificial nerve conduits for bridging extended gaps. In this study, we utilized chemically extracted acellular allogenic nerve segments implanted with autologous non-hematopoietic mesenchymal stem cells (MSCs) to repair a 40 mm defect in the rhesus monkey ulnar nerve. We found that severely damaged ulnar nerves were structurally and functionally repaired within 6 months following placement of the MSC seeded allografts in all animals studied (6 of 6, 100%). Furthermore, recovery with the MSC seeded allografts was similar to that observed with Schwann cell seeded allografts and autologous nerve grafts. The findings presented here are the first demonstration of the successful use of autologous MSCs, expanded in culture and implanted in a biological conduit, to repair a peripheral nerve gap in primates. Given the difficulty in isolating and purifying sufficient quantities of Schwann cells for peripheral nerve regeneration, the use of MSCs to seed acellular allogenic nerve grafts may prove to be a novel and promising therapeutic approach for repairing severe peripheral nerve injuries in humans.