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We report on the use and follow-up of direct peripheral nerve stimulation of the median nerve for the treatment of iatrogenic complex regional pain syndrome (CRPS). A 56-year-old woman presented with CRPS type II in the right forearm and hand, which had started after multiple carpal tunnel surgeries and had lasted for 2 years. The visual analogue scale (VAS) score was 8-10 out of 10. After a successful 15-day trial of median nerve peripheral nerve stimulation via a quadripolar lead in the right carpal tunnel space, an implantable pulse generator was inserted in the right infraclavicular space. The VAS score decreased to 1-2 out of 10 and the patient regained the ability to sleep. After 36 months of follow-up, the patient was still experiencing good pain relief without other treatment. We conclude that peripheral nerve stimulation is easy to use in pain management and could offer a valid treatment option for iatrogenic CRPS type II.

The outcome after nerve repair in adults is generally poor. We hypothesized that forearm deafferentation would enhance the sensory outcome by increasing the cortical hand representation. A prospective, randomized, double-blind study was designed to investigate the effects of cutaneous forearm anaesthesia combined with sensory re-education on the outcome after ulnar or median nerve repair. During a 2 week period, a local anaesthetic cream (EMLA (n = 7) or placebo (n=6) was applied repeatedly onto the flexor aspect of the forearm of the injured arm and combined with sensory re-education. Evaluation of sensory function was carried out at regular intervals and at 4 weeks after the last EMLA/placebo session. The EMLA group showed significant improvement compared to placebo in perception of touch/pressure, tactile gnosis and in the summarized outcome after 6 weeks. These results suggest that cutaneous forearm anaesthesia of the injured limb, in combination with sensory re-education, can enhance sensory recovery after nerve repair.

Carpal tunnel release (CTR) is regarded as a common and successful operative procedure in hand surgery. However, an increasing number of patients with complications have been referred to our hospital. This retrospective investigation was undertaken to clarify the reasons for persisting or recurrent symptoms in 200 patients who underwent secondary exploration during a 26 month period at a single institution. In 108 cases, the flexor retinaculum was found to have been released incompletely. In 12 patients, a nerve laceration had occurred during the primary intervention. In 46 patients, symptoms were due to the nerve being tethered in scar tissue. The re-exploration revealed circumferential fibrosis around and within the median nerve in 17 patients and a tumour in the carpal tunnel in four patients. In 13 patients, no specific reason was found for recurrence of symptoms. We conclude that CTR seems to be a widely underestimated procedure and revision surgery could be largely avoided by reducing technical errors during the primary operation.

This study analysed the costs of median and ulnar nerve injuries in the forearm in humans and factors affecting such costs. The costs within the health-care sector and costs of lost production were calculated in 69 patients with an injury to the median and/or ulnar nerve in the forearm, usually caused by glass, a knife, or a razorblade. Factors associated with the variation in costs and outcome were analysed. The total median costs for an employed person with a median and an ulnar nerve injury were EUR 51,238 and EUR 31,186, respectively, and 87% of the total costs were due to loss of production. All costs were higher for patients with concomitant tendon injuries (4 tendons). The costs within the health-care sector were also higher for patients who changed work after the injury and if both nerves were injured. Outcome was dependent on age and repair method.

The midline of the ring finger is classically considered as the neural watershed between the median and ulnar nerve sensory territories on the palmar surfaces of the fingers. Variations of this division exist and may be explained by a communicating branch between the third and fourth common digital nerves. The palmar sensibility patterns of fingers were assessed with Semmes Weinstein filaments after either a complete median or an ulnar nerve transection in 43 patients. Eight out of nine observed sensibility patterns could be explained by known anatomic types and subtypes of the communicating branch. The type of communicating branch, but not its subtype, could be established in the one remaining pattern.

The long-term outcome from silicone tube nerve repair was compared with the outcome from routine microsurgical repair in a clinical randomized prospective study, comprising 30 patients with median or ulnar nerve injuries in the distal forearm. Postoperatively, the patients underwent neurophysiological and clinical assessments of sensory and motor function regularly over a 5-year period. After 5 years there was no significant difference in outcome between the two techniques except that cold intolerance was significantly less severe with the tubular technique. In the total group there was ongoing improvement of functional sensibility throughout the 5 years after repair. It is concluded that tubular repair of the median and ulnar nerves is at least as good as routine microsurgical repair, and results in less cold intolerance.

A longitudinal dynamic cohort study was conducted on patients with median nerve injuries to evaluate the relative responsiveness of five sensibility tests: touch threshold using the WEST (monofilaments), static two-point discrimination, locognosia, a pick-up test and an object recognition test. Repeated assessments were performed starting at 6 months after surgery. In order to compare the relative responsiveness of each test, effect size and the standard response mean were calculated for sensibility changes occurring between 6 and 18 months after repair. Large effect sizes (>0.8) and standard response means (>0.8) were obtained for the WEST, locognosia, pick-up and object recognition tests. Two-point discrimination was hardly measurable at any time point and exhibited strong flooring effects. Further analysis of all time points was undertaken to assess the strength of the monotonic relationship between test scores and time elapsed since surgery. Comparison of monotonicity between the five tests indicated that the WEST performed best, whereas two-point discrimination performed worst. These results suggest that the monofilament test (WEST), locognosia test, Moberg pick-up test and tactile gnosis test capture sensibility changes over time well and should be considered for inclusion in the outcome assessment of patients with median nerve injury.

A 45-year-old right-handed woman was treated by endoscopic carpal tunnel release under local anaesthetic. When cutting the proximal half of the flexor retinaculum with the retrograde blade, she complained of an electric shock-like pain in her middle and ring fingers. Open exploration of the carpal tunnel was performed and a laceration of the middle/ring common digital nerve, which bifurcated at the unusually high level of the wrist crease, was found.

This study prospectively assessed the level of correlation between functional and electrophysiological recovery after median and ulnar nerve lacerations. Motor and sensory recovery were recorded clinically and electrophysiologically every 3 months in 24 patients with 29 complete median or ulnar nerve lacerations. The strength of agreement between the clinical motor score and the electrophysiological score was "fair", but in 41% a discrepancy was identified (kappa factor 0.39). Regeneration was not detected earlier by electrophysiology than by a thoroughly performed clinical evaluation. This suggests that electrophysiologic testing is of value as an adjunct to clinical assessment for evaluating cases in which there is clinical doubt as to the progress of regeneration and secondary surgery is contemplated.

This study presents a predicted five-year reference interval for the outcome following repair of the median or ulnar nerve in adults. Forty-four patients were examined with the use of a recently introduced model instrument for documentation after nerve repair that includes "sensory", "motor", and "pain/discomfort" outcomes which together constitute a summarized "total score". Analysis of the "total score" showed that follow-up time and age significantly influence the outcome. There were obvious inferior "motor" results after ulnar nerve injury, but these did not significantly influence the "total score". Significant improvements in the "total score" were seen throughout the follow-up period., (Copyright 2001 The British Society for Surgery of the Hand.)

The outcome of 38 median and ulnar nerve injuries at the wrist in 15 adults and 15 children were studied with a follow-up of at least 1 year. Each patient was assessed clinically and with nerve conduction studies. The results confirm a markedly superior sensory recovery in children. However the children had persistent motor deficiencies. This difference in the clinical results of adults and children was not reflected in the nerve conduction results which were similar in both groups., (Copyright 2001 The British Society for Surgery of the Hand.)

The hand is an extension of the brain, and the hand is projected and represented in large areas of the motor and sensory cortex. The brain is a complicated neural network which continuously remodels itself as a result of changes in sensory input. Such synaptic reorganizational changes may be activity-dependent, based on alterations in hand activity and tactile experience, or a result of deafferentiation such as nerve injury or amputation. Inferior recovery of functional sensibility following nerve repair, as well as phantom experiences in virtual, amputated limbs are phenomena reflecting profound cortical reorganizational changes. Surgical procedures on the hand are always accompanied by synaptic reorganizational changes in the brain cortex, and the outcome from many hand surgical procedures is to a large extent dependent on brain plasticity.

A silicone tube segment was used for repairing the median and ulnar nerves in the forearm. This study includes 26 patients (20 male and six female), with a mean age of 23 years (range, 18-26). Injuries were caused by saw, knife and glass accidents, the latter being most frequent. The mean interval between the injury and repair was 101 days. Fourteen patients had median nerve injuries, eight had ulnar nerve injuries and four had both median and ulnar nerve injuries. The technique was effective in the repair of peripheral nerve injuries with gaps of up to 3 cm, with better results in the ulnar nerves than in the median nerves.

Relatively little is known about the effects of chronic transection on human peripheral nerves. In this study intraoperative biopsies were obtained from proximal and distal nerve stumps and intervening neuromas resected before peripheral nerve reconstruction. Biopsies were collected from ten patients following differing types of nerve injury, with delays to repair ranging from 8 to 53 months. Nerves were examined by light and electron microscopy. In general, reinnervation was poor, although even following the most severe injuries, all of the distal stumps contained some regrowing axons, which were always associated with Schwann cells. Denervated Schwann cells, arranged in typical bands of Büngner were consistently present in each distal stump. Our findings confirm that the morphology of chronically denervated human peripheral nerves is essentially similar to that described in experimental models.

Five sheep underwent repair of the median nerve along with the establishment and repair of a brachial artery defect adjacent to the site of nerve injury. The defect in the brachial artery was of similar length to the nerve defect and lay in parallel with it. It was repaired using a reversed vein autograft harvested from one of the superficial veins of the arm. A further five sheep underwent similar treatment with the repair of the nerve delayed for 30 days after the establishment of the complicating vascular injury. Six months after the nerve repair, each group of sheep was assessed using electrophysiological and morphometric methods in order to establish objective indices of nerve recovery and regeneration. These results were compared with those from other sheep which had undergone nerve repair both immediate and delayed with no complicating injury and groups in which the complicating injury consisted of a cavity, fibrosis and haematoma. It was found that delay in the nerve repair and the presence of a complicating arterial injury, both separately and additively, contributed to a poorer outcome in recovery of nerve function and maturation. The effect of an arterial injury, in both of these respects, was to produce a worse outcome than the presence of a cavity with fibrosis and haematoma.

Migration of orthopaedic implants such as K-wires is not unusual, but migration due to an improperly constructed brace has not been reported. This report describes such a mechanism in a case complicated by acute median nerve injury.

Median nerve contusion occurred in two patients treated by endoscopic carpal tunnel release. We discuss the possible cause of this complication and how to avoid it.

We report 18 children (12 boys and six girls) with a mean age of 6.1 years who sustained lacerations of the median nerve. Associated injuries to other structures occurred in 15 children. Treatment was by primary epineural repair. All the children were assessed at least 1 year after injury. The mean return of motor power to the opponens pollicis was 4.5 with a range of 3 to 5 (MRC scale) and the mean static 2-point discrimination was 5 mm (range 2-10 mm). All children showed a full functional recovery as assessed by the Bruininks-Oseretsky test. Primary epineurial repair in children leads to very satisfactory motor and sensory results. A fully functional hand can be expected.

A descriptive severity scoring system for injuries to the hand, distal to the carpus, has been designed. Each ray of the hand is assessed separately. Each ray's score is then multiplied by a weighting factor for that ray and added to the scores of the other rays to obtain a total score for the injury. This system has been tested on a series of specimen injuries and compared with the opinion of experienced hand surgeons. A retrospective study of hand injuries has also been conducted, and the Hand Injury Severity Score (HISS) has been found to closely correlate with return to work. Four grades of increasing severity of hand injury have been described. Although this system has been designed as a research tool, it is envisaged that it would be a useful immediate measure of severity and a guide to likely outcome.

Two cases of nerve injury are reported following steroid injection as treatment for carpal tunnel syndrome. One caused an ulnar nerve lesion that recovered well. The other caused a more severe median nerve lesion which responded poorly to conservative treatment. Steroid injection for carpal tunnel syndrome is generally safe but nerve injury may occur and is difficult to treat.

A case of median nerve injury caused by an unsuspected foreign body is described. The mechanism was not recognized at the time of injury. The suspicion of a penetrating missile injury was raised only with the aid of radiographs. At operation the foreign body was found in the substance of the median nerve.

To test the hypothesis that cognitive capacity is correlated with the outcome of functional sensibility after nerve repair, 19 patients were evaluated 2 to 5 years after median or ulnar nerve repair at the distal forearm level. The sensory evaluation included tests for functional sensibility as well as assessments addressing perception thresholds for touch/pressure and vibration. Psychometric tests for cognitive capacity were also carried out. Multiple regression analysis, correcting for the effect of age and the ability to perceive touch/vibration, was used to investigate the relationship between functional sensibility and cognitive capacity, and to determine which of the tested central nervous factors had the greatest influence on the outcome of recovery of functional sensibility. On a ranking list of such factors verbal learning and visuo-spatial logic capacity were the most important ones, indicating significant correlations with functional sensibility. It is concluded that cognitive capacity factors may play an important role for the functional outcome following nerve repair and that variations in such factors may help to explain the variability in the outcome of nerve repair.

Transected median nerves in the forearm of two male patients, 12 and 21 years of age, were treated with a chamber technique leaving a 3 to 5 mm gap between the nerve ends. The nerve ends were enclosed in a silicone tube of such a dimension that would not cause compression of the nerve. Post-operative examination including sensory evaluation and assessment of muscle contraction force was carried out after 3 years. In both cases there was excellent motor recovery of the thenar muscles. Outgrowth of sensory fibres was remarkably fast, resulting ultimately in functional sensibility allowing almost normal hand function. 2PD was < or = 6 mm (12-year-old patient) and 8 to 10 mm (21-year-old patient) respectively. In one case the silicone tube was re-explored because of minor local discomfort 2 years after the repair. The former gap was bridged by a smooth continuous nerve-like structure of the same diameter as the adjacent nerve trunk and with no signs of neuroma formation or compression of the nerve.

83 hands in 69 patients had endoscopic carpal tunnel release by the Chow method over a 14-month period. 78% of these had a satisfactory outcome with relief of symptoms and no complications. Poor results were explained by incomplete ligament division (five patients), wrong diagnosis (two hands), and post-operative nerve problems (five hands). Two patients after Colles' fractures had unsatisfactory results. Serious complications included two median nerve lacerations. One of these was clearly a result of deviation from the standard protocol. The authors believe that the technique has advantages over open release but they are divided on whether the benefits outweigh the risk of nerve injury.

Transection of both median and ulnar nerves provides an objective model to compare sensory and functional recovery. 22 patients were evaluated after nerve repair. The mean age was 30 years and the mean time since surgery 80 months. Primary direct suture was performed in 15 patients and six grafts were necessary. Median nerve suture and ulnar nerve graft were combined in one case. Both sensory and functional evaluation were completed. Statistical evaluation analyzed the relationship between age, injury location, mechanism, type of rehabilitation and the result, and the relationship between two-point discrimination distance (2-PD) and the functional score. According to the S0 to S4 grading, only 26.5% (ulnar) and 31% (median) of direct suture cases achieved S3+ or more. All nerve grafts in adults were poor. A strong relationship was found between two-point discrimination distance (moving and static) and the functional result, even after multivariate analysis. A modification of the Medical Research Council's classification is suggested.

Two cases of subacute median nerve compression in children following trauma are presented. The first highlights problems of incised wounds around the wrist. The second illustrates an unusual presentation of nerve compression following a blunt injury.

A clinical and electromyographic study of major nerve transections at the wrist in 22 patients has shown that electrical recovery nearly always occurs in the intrinsic muscles, despite the absence of clinically detectable function. There appears to be a level of electrical reinnervation above which clinically detectable intrinsic muscle power is usually present. This level would appear to be 50% of the contralateral maximum evoked muscle action potential; above this the "myth" of clinical recovery becomes a reality.

A case is presented of an anomalous course of the palmar cutaneous branch of the median nerve. Wide and meticulous exposure is necessary to avoid injury to all variations of this nerve and the use of a "safe" incision will not always avoid risk of injury.

The outcome of 15 patients who sustained simultaneous laceration of the median and ulnar nerves with flexor tendons at the wrist is described. Primary nerve repair yielded satisfactory results, the median nerve achieving a better outcome than the ulnar nerve. Most patients regained a functional range of wrist movement. Flexor tendons yielded the poorest results. A functional, albeit impaired outcome can usually be anticipated following this severe injury.

132 patients with injuries to the median nerve were assessed on average 10.4 years after repair. There were 106 males and 26 females, with a mean age of 28.4 years. Most of the nerve lesions were sharp (76) or blunt (47) injuries. Division was total in 87 cases, and most were at the wrist level. Secondary repair was performed in 34 cases and fascicular grafting in 98 cases. The average gap was 5.8 cm. A quantitative evaluation and grading according to the MRC classification was created to reflect sensory and motor recovery. Excellent or good results were obtained in only 49.2%. The age of the patient, the width of contusion, the pre-operative delay, the length of grafting and the level of the injury influenced the results significantly. The result of nerve repair was poor in patients aged over 54 years, when the level of the injury was more than 56 cm proximal to the finger tip, if the pre-operative delay was more than 24 months, or if the graft length was more than 70 mm.

This study is a review of 127 hands in 100 patients in whom one or two FDS tendons were used to correct claw-hand deformity and/or loss of opposition of the thumb. In lumbrical replacement the results were graded as excellent in 16 hands (21%) and good in 43 hands (57%). For opponensplasty the results were excellent in 26 hands (32%) and good in 42 hands (51%). Possible defects that can develop in the donor finger are: swan-neck deformity, flexion posture of the DIP joint, not as part of the swan-neck deformity, check-rein deformity or flexion contracture, and insufficient finger flexion. Of the 158 fingers swan-neck deformity was seen in 15%, DIP flexion in 29%, check-rein deformity in 26% and insufficient finger flexion in 18%. The latter occurred with another defect. In 48 fingers (30%) no defects were observed.

The literature indicates that tourniquet-induced neurological injuries are relatively common and frequently occur at a subclinical level. In order to evaluate the pressure transmitted to the major peripheral nerves of the arm by an externally applied pneumatic tourniquet, a fully implantable biomedical pressure transducer was placed adjacent the radial, median and ulnar nerves in six cadaver upper extremities of average dimensions. This sensor allowed accurate, reproducible measurements of perineural pressures without requiring significant disruption of the normal anatomical structures of the test limb for its installation. At levels of tourniquet cuff inflation which are commonly used in clinical practice, there was little or no decrease in the pressure detected in the perineural regions over that applied to the surface of the limb. In addition, there was a steep gradient of perineural pressure between locations beneath the edge of the cuff and those under its midpoint. This was most marked at the highest levels of tourniquet inflation. At presently accepted levels of inflation, pneumatic tourniquet cuffs transmit high pressures to the peripheral nerves without any significant attenuation by the intervening soft tissues. The distribution of these forces is one which may subject the underlying nerves to deleterious shear forces, especially at higher levels of inflation.

The results of operation on 71 volar wrist ganglia are reported. The recurrence rate was 28%, occurring between 1 and 144 months (median: 5 months). The highest risk of recurrence is in a male patient, under 30 years of age, in a manual occupation, operated on by a junior surgeon. The use of a post-operative plaster slab seemed to be followed by significant wrist stiffness. 28% of the patients had evidence of damage to the palmar cutaneous branch of the median nerve. It is suggested that this could be avoided by positive identification of this nerve at operation.

Fracture of an acupuncture needle resulted in a foreign body within the carpal tunnel of a patient who then developed median neuropathy. The needle fragment was recovered from within the median nerve during carpal tunnel release, with rapid post-operative relief of symptoms. Development of peripheral neuropathy is a potential complication of acupuncture.

Erik Moberg pioneered the idea of validating measures of sensory function following peripheral nerve suture by correlating their results with those of functional tests. However it is important that powerful prior variables (age at suture, time elapsed since suture and delay between injury and suture) be controlled. Failure to do this may result in spurious correlations, as illustrated by analysis of two sets of data, one collected by the author and the other given in the classic paper of Onne (1962).

The transfer of sensitive dorsal rami of the ulnar nerve (two cases) and of two sensitive dorsal rami of the radial nerve (five cases) was accomplished in order to restore the sensitivity of the first three finger tips in patients suffering from serious and longstanding inveterate lesions of the median nerve. The Authors describe the two surgical techniques in detail and, according to the satisfactory results obtained, specify the indications and advantages of this operation.

Transfer of sensory branches of the radial nerve to sensory branches of the ulnar or median nerves has been carried out to restore sensitivity to the digits in patients suffering from severe, longstanding and irreparable damage to the median or ulnar nerves, due to war injuries. The author describes the two surgical techniques in detail and reports the results obtained.

It has been recognised for a long time that damage to the median or ulnar nerves is usually followed by slowing of growth of the fingernails. In the past, this has always been ascribed to immobilization of the appropriate digits, rather than to a neurotrophic factor. No other nail changes appear to have been described in association with nerve damage. We present two patients with marked nail changes following median nerve injury, in which immobilization does not appear to be responsible.

A quick and simple method of measuring the electrical resistance of the skin is presented as an objective test of peripheral nerve injury. Patterns of altered skin resistance in patients with nerve injuries were found to coincide with operative findings. The method can be used in the preoperative assessment of hand injuries and to monitor the recovery of nerve function.

Two electrical methods of assessing nerve function have been developed and have proved useful in clinical practice. Their role has been established in the diagnosis of injury, prognosis and the assessment of progress following repair. They provide an easily performed, objective measurement of nerve function. An indication of regeneration can be obtained some months ahead of accepted clinical signs. Failure to regenerate is noted equally early allowing re-exploration and secondary procedures to be undertaken sooner. Patient motivation is enhanced and a strong Doctor/Patient relationship is established by the ability to predict accurately the development of subsequent clinical signs and the extent of eventual nerve recovery.

Carpal tunnel release was performed under local anaesthesia in 124 wrists of 108 patients. The local anesthetic was injected into the carpal tunnel and into the subcutaneous tissue under the line of the skin incision. A tourniquet was used in all cases. Analgesia was complete in all but six patients. Only one patient had real difficulty in tolerating the tourniquet. In 18 cases the median nerve, when exposed at operation, showed evidence of some damage caused by the needle or by injection of local anaesthetic but, at follow-up, no symptoms or signs related to this damage were found.

The terminal branch of the anterior interosseous nerve is described anatomically and demonstrated histologically. Injury to this nerve can be the source of persistent, dull aching volar wrist pain. Suitability for partial volar wrist denervation is determined by functional testing before and after a diagnostic nerve block. Experience with twelve patients with this problem is presented.