Aberrant branches of the radial digital nerve in the index and middle finger: two case-reports.

This report describes two incidental findings of aberrant branches of the radial digital nerves in the middle finger of a 52-year-old man who cut himself with a grinding machine, and in the index finger of a 45-year-old female who sustained a flexor sheath infection following a dog bite. In both patients, two equally sized radial digital nerves were found and both nerves originated from one common digital nerve.

Treatment of a little finger synovial cyst by repair of an opening in the wrist capsule: case report.

As synovial fluid from the wrist may leak into the ulnar bursa and from there into the flexor synovial sheath in the little finger, the origin of a synovial cyst of the pulp of the little finger may be in the wrist. Here we present the surgical treatment of a patient with a synovial cyst of the pulp of the little finger by surgery of the wrist and palm of the hand after failed conservative treatment.

Porosity of the wall of a Neurolac nerve conduit hampers nerve regeneration.

One way to improve nerve regeneration and bridge longer nerve gaps may be the use of semipermeable/porous conduits. With porosity less biomaterial is used for the nerve conduit. We evaluated the short-term effects of porous Neurolac nerve conduits for in vivo peripheral nerve regeneration. In 10 male Black Hooded rats, a gap of 10 mm was bridged by a porous Neurolac nerve conduit. Evaluation point ranged from 3 to 12 weeks. The sciatic nerve function was not measurable due to automutilation and flexion contractures. The gait-stance duration showed no improvement with time, indicating a disturbed walking pattern. The nerve guides showed very fast degradation with swelling, fragmentation, and collapse. Furthermore, a severe foreign body reaction occurred. Nerve regeneration was severely hampered. This study showed no beneficial effects of porous Neurolac nerve conduits when compared with previous findings with nonporous copolymeric nerve guides of a slightly different composition.

Modification of Phalen's wrist-flexion test.

Phalen's test, with more than 100 degrees of elbow flexion, is not always comfortable for patients with elbow pathology. Therefore, we suggest a modification of the test with the patient having both arms resting on a pillow or arm-holders in a relaxed position, the hands floating at the end, and the examiner passively flexing (or reversed: extending) the hands up to 90 degrees.

Endoscopic single-incision extensor indicis transposition for extensor pollicis longus reconstruction.

Traditional methods for harvesting the extensor indicis (EI) tendon for transposition to the extensor pollicis longus (EPL) tendon using direct visualization commonly require 3 incisions. The authors describe an endoscopic EI tendon transposition for EPL tendon reconstruction as an alternative technique for the traditional open technique. This new modification of endoscopic EI transposition to EPL has the benefit over the standard harvesting technique of only 1 incision to accomplish the complete procedure and results in less scarring. To date, the authors have only operated on ruptures after radius fractures without significant synovitis in the area of the extensor compartment.

Long-term reinnervation effects after sciatic nerve lesions in adult rats.

Transection of the sciatic nerve in adult rats induces drastic changes in hindleg muscles. Earlier, we demonstrated that the reinnervated soleus (SOL) muscle, 21 weeks after a transection mainly contains type II fibers. This is in striking contrast to normal muscle, which consists to 80% of type I muscle fibers. Also we observed 13.9% of the fibers to be polyneurally innervated. The problem of the present study is whether these changes are reversible after Longer survival periods. Therefore, the SOL was studied 60 weeks after transection and reconstruction by an autologous nerve graft. In six rats, we studied muscle fiber distributions by monoclonal antibodies, and innervation patterns by cholinesterase staining and AgNO3 impregnation. Still at 60 weeks, only 20% of the muscle fibers are of type I and this is similar to results at 21 weeks, indicating that no recovery to the normal has been reached by that age. Furthermore, 20% of the endplates in the reinnervated SOL were polyneurally innervated, but we also observed this in 10% of the endplates on the control side. These increases, compared to data at 21 weeks, are interpreted as an aging effect.

Functional and morphological assessment of a standardized rat sciatic nerve crush injury with a non-serrated clamp.

Peripheral nerve researchers frequently use the rat sciatic nerve crush as a model for axonotmesis. Unfortunately, studies from various research groups report results from different crush techniques and by using a variety of evaluation tools, making comparisons between studies difficult. The purpose of this investigation was to determine the sequence of functional and morphologic changes after an acute sciatic nerve crush injury with a non-serrated clamp, giving a final standardized pressure of p = 9 MPa. Functional recovery was evaluated using the sciatic functional index (SFI), the extensor postural thrust (EPT) and the withdrawal reflex latency (WRL), before injury, and then at weekly intervals until week 8 postoperatively. The rats were also evaluated preoperatively and at weeks 2, 4, and 8 by ankle kinematics, toe out angle (TOA), and gait-stance duration. In addition, the motor nerve conduction velocity (MNCV) and the gastrocnemius-soleus weight parameters were measured just before euthanasia. Finally, structural, ultrastructural and histomorphometric analyses were carried out on regenerated nerve fibers. At 8 weeks after the crush injury, a full functional recovery was predicted by SFI, EPT, TOA, and gait-stance duration, while all the other parameters were still recovering their original values. On the other hand, only two of the histomorphometric parameters of regenerated nerve fibers, namely myelin thickness/axon diameter ratio and fiber/axon diameter ratio, returned to normal values while all other parameters were significantly different from normal values. The employment of traditional methods of functional evaluation in conjunction with the modern techniques of computerized analysis of gait and histomorphometric analysis should thus be recommended for an overall assessment of recovery in the rat sciatic nerve crush model.

Use of skeletal muscle tissue in peripheral nerve repair: review of the literature.

The management of peripheral nerve injury continues to be a major clinical challenge. The most widely used technique for bridging defects in peripheral nerves is the use of autologous nerve grafts. This technique, however, necessitates a donor nerve and corresponding deficit. Many alternative techniques have thus been developed. The use of skeletal muscle tissue as graft material for nerve repair is one example. The rationale regarding the use of the skeletal muscle tissue technique is the availability of a longitudinally oriented basal lamina and extracellular matrix components that direct and enhance regenerating nerve fibers. These factors provide superiority over other bridging methods as vein grafts or (non)degradable nerve conduits. The main disadvantages of this technique are the risk that nerve fibers can grow out of the muscle tissue during nerve regeneration, and that a donor site is necessary to harvest the muscle tissue. Despite publications on nerve conduits as an alternative for peripheral nerve repair, autologous nerve grafting is still the standard care for treatment of a nerve gap in the clinical situation; however, the use of the skeletal muscle tissue technique can be added to the surgeon's arsenal of peripheral nerve repair tools, especially for bridging short nerve defects or when traditional nerve autografts cannot be employed. This technique has been investigated both experimentally and clinically and, in this article, an overview of the literature on skeletal muscle grafts for bridging peripheral nerve defects is presented.

Rehabilitation strategy using enhanced housing environment during neural regeneration.

The influence of an enriched environment on the recovery of nerve function was studied after a sciatic nerve lesion and repair. A sciatic nerve gap of 15 mm was bridged in 12 rats using autologous nerve grafts. The rats were housed either in an enriched environment or in standard cages. In the enhanced housing environment, the rats were forced to move by dissociating food and water sources, including wire for foot gripping instead of flat plastic floors, and wooden play toys. Locomotor behavior was recorded on tape with a digital videorecorder and behavioral data were compared with those of a group of six unoperated rats. The video-recordings were analyzed for the stance factor (SF) as well as several other aspects of the rat's walking pattern. Walking was evaluated between 10 and 21 weeks after the operation. Differences in walking behavior between rats raised in an enriched environment and rats raised in standard cages could not be demonstrated. Differences in walking behavior between male and female rats were not found either. But data differed significantly at all ages with rats of the control group. Automutilation of parts of the denervated foot revealed a significant difference in both experimental groups, occurring less often in the enriched environment group.

Long-term regeneration of the rat sciatic nerve through a biodegradable poly(DL-lactide-epsilon-caprolactone) nerve guide: tissue reactions with focus on collagen III/IV reformation.

Long-term studies on nerve-guide regeneration are scarce. Therefore, in rats, long-term (16 months) sciatic nerve regeneration through poly(DL-lactide-epsilon-caprolactone) [poly(DLLA-epsilon-CL)] nerve guides was studied and compared with the nonoperated control side. Poly(DLLA-epsilon-CL) degradation and possible long-term foreign body reaction against poly(DLLA-epsilon-CL) nerve guides, as well as the distribution of both collagen type III and IV were studied. In vivo poly(DLLA-epsilon-CL) studies have been performed before but not for such long time points; also, a detailed analysis of collagen III/IV has not been presented before. The results demonstrate that biodegradable poly(DLLA-epsilon-CL) nerve guides yield good nerve regeneration and collagen III/IV deposition relative to the anatomy of the control side. Regenerated nerve showed almost similar collagen type III/IV distribution patterns as compared with the nonoperated control side, although the delineation of matrix was clearer in the control side. The relative amount of collagen III and IV immunostaining in nerve cross-sections did not, however, differ between the control nerve tissue and the operated side after 16 months. After 16 months of implantation, however, some very small fragments of biomaterial could still be found on the edge of the epineurium of the regenerated nerve, indicating remnants of a secondary foreign body reaction. The biomaterial fragments and foreign body reaction did not influence the nerve regeneration process after 16 months. Biodegradable poly(DLLA-epsilon-CL) nerve guides are useful for long-term bridging of short peripheral nerve gaps.

In vitro degradation and biocompatibility of poly(DL-lactide-epsilon-caprolactone) nerve guides.

Bridging nerve gaps by means of autologous nerve grafts involves donor nerve graft harvesting. Recent studies have focused on the use of alternative methods, and one of these is the use of biodegradable nerve guides. After serving their function, nerve guides should degrade to avoid a chronic foreign body reaction. The in vitro degradation, in vitro cytotoxicity, hemocompatibility, and short-term in vivo foreign body reaction of poly((65)/(35) ((85)/(15) (L)/(D)) lactide-epsilon-caprolactone) nerve guides was studied. The in vitro degradation characteristics of poly(DLLA-epsilon-CL) nerve guides were monitored at 2-week time intervals during a period of 22 weeks. Weight loss, degree of swelling of the tube wall, mechanical strength, thermal properties, and the intrinsic viscosity of the nerve guides were determined. Cytotoxicity was studied by measuring the cell proliferation inhibition index (CPII) on mouse fibroblasts in vitro. Cell growth was evaluated by cell counting, while morphology was assessed by light microscopy. Hemocompatibility was evaluated using a thrombin generation assay and a complement convertase assay. The foreign body reaction against poly(DLLA-epsilon-CL) nerve guides was investigated by examining toluidine blue stained sections. The in vitro degradation data showed that poly(DLLA-epsilon-CL) nerve guides do not swell, maintain their mechanical strength and flexibility for a period of about 8-10 weeks, and start to lose mass after about 10 weeks. Poly(DLLA-epsilon-CL) nerve guides were classified as noncytotoxic, as cytotoxicity tests demonstrated that cell morphology was not affected (CPII 0%). The thrombin generation assay and complement convertase assay indicated that the material is highly hemocompatible. The foreign body reaction against the biomaterial was mild with a light priming of the immunesystem. The results presented in this study demonstrate that poly((65)/(35) ((85)/(15) (L)/(D)) lactide-epsilon-caprolactone) nerve guides are biocompatible, and show good in vitro degradation characteristics, making these biodegradable nerve guides promising candidates for bridging peripheral nerve defects up to several centimeters.

Methods for the experimental functional assessment of rat sciatic nerve regeneration.

In experimental peripheral nerve studies, the rat sciatic nerve model is widely used to examine functional changes after different surgical repairs or pharmacological treatments, following nerve injury. The number and diversity of tests which have been used to assess functional recovery after experimental interventions often makes it difficult to recommend any particular indicator of nerve regeneration. Functional assessment after sciatic nerve lesion has long been focused on walking track analysis, therefore, this article describes in more detail the method to obtain and measure the walking tracks in order to calculate the sciatic functional index (SFI). However, it is important to note that the validity of the SFI has been questioned by several researchers. In addition, the present review includes other traditional tests described in the experimental peripheral nerve literature regarding the rate of return of motor function and sensation, such as the extensor postural thrust (EPT), nociceptive function, and the gastrocnemius-soleus weight parameters. In the last decade, several authors have designed a series of sensitive quantitative methods to assess the recovery of hind limb locomotor function using computerized rat gait analysis. This study aims to review kinematic measures that can be gathered with this technology, including calculation of sciatic functional index, gait-stance duration, ankle kinematics and toe out angle (TOA). A combination of tests, each examining particular components of recovered sensorimotor function is recommended for an overall assessment of rat sciatic nerve regeneration.

Carpal tunnel syndrome caused by a giant cell tumour of the flexor tendon sheath.

A 76-year-old woman developed right carpal tunnel syndrome after being conservatively treated for tenosynovitis of the flexor tendons with associated mild carpal tunnel syndrome. A magnetic resonance imaging scan showed a tumour in the carpal tunnel. Re-exploration showed that the median nerve was being compressed by a giant cell tumour of the flexor tendon sheaths. Appropriate imaging is advised in patients with additional findings (such as swelling) or in patients with secondary carpal tunnel syndrome and incomplete response to conservative treatment, to exclude a space-occupying lesion.

Recovery of two-point discrimination function after digital nerve repair in the hand using resorbable FDA- and CE-approved nerve conduits.

This article aims to provide an overview of all clinical studies reporting sensory outcome as measured by two-point discrimination after digital nerve repair in the hand using resorbable Food and Drug Administration (FDA)- and CE-approved nerve conduits. The minimum follow-up for inclusion in this review was 11 months. In total, 235 nerve reconstructions could be classified. A total of 169 (72%) nerve reconstructions with a synthetic polyester-based nerve conduit were included; the other 66 nerves were reconstructed with collagen-based nerve conduits. To obtain the most reliable and comparable data, outcomes of each study were reclassified in the classification system as was used in the first two prospective randomised multicentre studies on the use of resorbable nerve conduits for repair of digital nerve gaps in the hand. Of the 235 nerve reconstructions, 171 (73%) nerve reconstructions showed good to excellent functional outcome. As many as 64 (27%) of the nerve reconstructions had a poor outcome. Based on the available data in this article at this moment, we conclude that digital nerve gaps up to 4 cm can be bridged by resorbable nerve conduits with a sensory outcome that can be qualified as good to excellent in almost 75% of cases after 11 months. Differences between FDA- and CE-approved nerve conduits could not be detected, apart from the rates of protrusion that were not observed using collagen-based nerve conduits.