[Specific strength measurement of musculus abductor pollicis brevis in order to objectively evaluate muscle regeneration after carpal tunnel release surgery]. / Objektivierung der Muskelregeneration durch Messung der Kraft des Musculus abductor pollicis brevis nach Karpaldachspaltung.

47 patients with a carpal tunnel syndrome were preoperatively examined not only by electrophysical studies (nerve velocity and distal motoric latency) and clinical tests (Phalen's sign, Tinel's sign) but also by measuring the strength of the M. abductor pollicis brevis with a specifically designed strength-testing unit. 30 patients agreed to participate in a voluntary postoperative examination. In the 45 degrees -measurement there was a relative strength loss of the injured hand's thumb of about 25 % in comparison with the healthy hand preoperatively. The postoperative strength disadvantage amounted to only 10 %. Measurement of the strength in the neutral zero method showed a relative strength loss of the injured hand's thumb of 8 % while postoperatively there was even a strength advantage of 9 % in comparison with the thumb of the healthy hand. Both methods showed a relevant and significant postoperative strength increase of the injured hand's thumb. We could prove a significant correlation (p = 0.03) of the neutral zero strength measurement and the distal motoric latency of the median nerve. Furthermore, we could show a trend for a correlation between the neutral zero strength measurement and the median motoric velocity. In conclusion, it can be said that the special strength measurement of the M. abductor pollicis brevis is an important parameter to objectively evaluate the motoric symptomatology in carpal tunnel syndrome patients.

[Reoperations for CTS because of recurrence or for correction]. / Rezidiv- und Korrektureingriffe beim Karpaltunnelsyndrom.

BACKGROUND: With an increasing number of operative procedures for CTS, the number of reoperations is increasing too. These procedures are not in general performed because of recurrence, other reasons may play a role for the failure of the initial operation or recurrent symptoms. METHODS AND CLINICAL MATERIAL: Revision procedures performed in 57 patients in the practice for peripheral neurosurgery from January to September 2004 were analyzed for incision, intraoperative findings, method of operation, electrophysiological findings, and revised diagnosis. Moreover, the data were compared with 185 revision procedures performed in the years from 1986 up to 1994. RESULTS: 2.4 % of all CTS operations were revision procedures (in the former time period 1.5 %). In 59 % of revision operations (former 50 %) an incomplete release of the transverse ligament was found, in 27 % (former 31 %) typical recurrence, in 5 % (former 6 %) nerve lesions, and in 9 % (former 13 %) no abnormalities so that other reasons for complaints of mainly radicular lesions must be assumed. In cases of incomplete release of the transverse ligament, only in 16 % of the patients were normal skin incisions seen, but in 56.3 % there were small incisions (i.e., short or mini-incisions). Typical CTS recurrence occurred mainly in hemodialysis patients, nerve lesions were seen mainly when endoscopic procedures were performed. CONCLUSION: Diagnostic problems because of incomplete or misinterpreted ENG findings may lead to delayed or useless primary as well as revision operations. Too small incisions but also endoscopic procedures used by less experienced surgeons are accompanied with an increased risk for avoidable revisions and nerve lesions. Not only for forensic reasons but also in view of quality management, procedures for correction (of operative failure) should be distinguished from those for recurrence.

[Carpal tunnel syndrome in haemodialysis patients: analysis of clinical and electrophysiological findings in 268 patients (395 hands)]. / Das Karpaltunnelsyndrom bei dialysepflichtigen Patienten: Analyse klinischer und elektrophysiologischer Befunde bei 268 Patienten (395 Händen).

PURPOSE/BACKGROUND: Along with arthropathies, carpal tunnel syndrome (CTS) may occur in patients on chronic haemodialysis, its incidence is correlating with the duration of the haemodialysis treatment. To evaluate clinical and electrophysiological findings, relation of the disease to the side of the arteriovenous shunt, gender ratio, and a concurrent tendovaginosis stenosans (TVS), 268 haemodialysis-patients with CTS or recurrent CTS were retrospectively analyzed. METHODS AND (CLINICAL) MATERIAL: Over a period of ten years (1994 - 2003), 268 haemodialysis patients presented to our peripheral neurosurgery practice with CTS or recurrent CTS. Diagnosis was confirmed with clinical and electrophysiological findings. The patients were divided into three groups based on their severity of disease as follows: Patients with only intermittent paraesthesias (CTS I degrees ), with persistent numbness in the area supplied by the median nerve (CTS II degrees ), and with paresis of the thenar muscles (CTS III degrees ). The average distal motor latency (DML), loss of sensory nerve action potentials (SNAP), and/or motor action potentials (MAP) were used as electrophysiological parameters. RESULTS: During the above mentioned period, 395 primary CTS-operations were performed in 268 patients, and 83 operations of recurrent CTS in 53 patients, i.e. approximately 50 % of the patients had bilateral operations. A second recurrency of CTS was treated in 29 hands of 20 patients and a third recurrency in six hands of five patients. The ratio of women to men suffering from CTS was approximately 1 : 1. TVS occurred concurrent in 22 % of the patients in one hand and in 11.6 % in both hands. Decompression of the median nerve was performed more frequently on the shunt-side, or primarily on the shunt-side, if both hands were affected, as compared to the contralateral side. Recurrency of CTS, possibly a second or third recurrency, was found with increasing time of dialysis. The temporal interval from one operation to the other had a declining tendency. Whereas at the time of the primary operation in 27.4 % of the patients a CTS I degrees was found, patients suffered from CTS II degrees or III degrees in case of a second or third recurrency. Deterioration of clinical signs in CTS recurrency was reflected by the electrophysiological findings with an increasing loss of SNAP and MAP. CONCLUSION: CTS is a typical complication of chronic haemodialysis, and differs from idiopathic CTS by a gender ratio of 1 : 1, a high frequency of concurrent TVS, as well as a tendency to recur. Since compression of the median nerve was found preferentially on the shunt-side, haemodynamic factors may play a role in the pathogenesis of the disease in addition to amyloidosis. Haemodialysis patients complaining of paraesthesia in their hands should undergo electrophysiological examination, even if a successful CTS-operation was performed in the past.

[Glomus tumours of the extremities: localisation and operative treatment in 36 cases]. / Zur Lokalisation und operativen Behandlung der Glomustumoren der Extremitäten. Bericht über 36 Fälle.

Glomus tumours are rare lesions and perhaps for that reason they often pose diagnostic difficulties. They are benign tumours first described by Masson in 1924, and they are derived from the glomus body responsible for blood and temperature regulation. In this study, 36 cases were reported out of a total of more than 35 000 operations in an eleven-year period. Among them were 23 women (average age 51 years) and 13 men (average age 52 years). They were diagnosed correctly after a mean period of eight years from onset of symptoms until surgery. In women, glomus tumours occurred almost always in the distal phalanx, especially in the subungual area, in men without any predisposing localisation. Two third of the patients presented with local pain and cold intolerance, and 50 percent of the patients with subungual localisation had a bluish discoloration beneath the nail. In three patients without visible or palpable signs additional MRI confirmed the diagnosis. All patients were operated upon in local anaesthesia and in a bloodless field. In the cases with subungual localisation, we mostly used a transungual triangular incision with good cosmetic results. In 94 % of the patients the lesion has been cured, in one case symptoms persisted, and in another case recurrence occurred. Conclusion. In patients with severe local pain, especially in the distal phalanx, glomus tumours should be considered. In cases where no clinical signs can be found, MRI - although not specific - may be helpful in establishing the correct diagnosis. The operation can be performed in local anaesthesia, bloodless field and in subungual localisation through a triangular incision. Recurrences may occur.

Electrophysiological study of regenerated rabbit tibial and peroneal nerves: autologous versus non-neural grafts.

In recent years, successful experimental nerve regeneration using extracellular matrix as implants has been reported. In the present study, we compared peripheral nerve regeneration through implants of amnion membrane matrix (AMM) and umbilical cord membrane matrix (UCMM) versus autologous nerve transplantation, bridging gaps 8-12 mm in length in rabbit tibial and peroneal nerves. The data are based on direct nerve stimulation and recording of somatosensory evoked potentials (SEPs) and muscle action potentials (MAPs) to measure functional recovery after these different types of neuroplastic bridging. Incomplete regeneration was demonstrable as missing SEPs (15-22%), missing MAPs (17-42%), a mean delay of SEPs and distal motor latencies of approximately 40-50% compared with a normal control group, and slowed motor conduction velocities by approximately 50%. There were no significant differences between the three different types of neuroplastic bridging. Most of the AMM and UCMM implants (80-100%), but none of the autologous nerve transplants, caused inadequate connections with peripheral targets. We conclude that extracellular matrix implantation represents a useful experimental model for studying the biological basis of nerve regeneration, but does not yet serve as a tool for therapeutic applications.