In severe cases of brachial plexus lesion in spite of useful muscle regeneration patients can not exploit the results because in lacking of global function. The majority of the treated patients showed benefit of reconstructive procedures.

When the author started his training as a neurologist exactly 50 years ago, the only diagnostic tools used were clinical examination and testing of excitability of peripheral nerves and muscles by electrical square waves impulses. The EMG was introduced to Switzerland in 1953. In the early fifties of the last century the carpal tunnel syndrome was redetected and became clinically important. Then a real boom of entrapment syndromes began and also became somewhat exaggerated. Lesions of peripheral nerves were repaired 50 years ago by every general surgeon and suture under tension was too frequently applied. Finally interponates were used. It had to be shown that only autotransplantates were really successful. The technique of peripheral nerve surgery got more and more sophisticated and more and more specialists were trained.The widespread use of the microscope started. Nowadays the peripheral nerve surgeon is by himself an excellent specialist, not only in the treatment but also in the diagnosis of peripheral nerve lesions.

Circular shaped specimens (45 mm diameter) were excised from the medial and lateral lower leg and shortly post mortem tested in an apparatus consisting of six machine axes (12 loading points arranged at the circumference of a 30 min diameter circle). The apparatus developed by the authors allows deformation controlled loading of the specimens. Used were the following deformation procedures. Deformation was applied in each direction of the machine axes, with a ratio of the main components kept constant, as well as radial symmetric deformation serving, as reference states. The deformation was applied step by step. The necessary forces in each step and loading points were measured using special load cells. From these measurements the rheological response (relaxation time and the elastic contribution to stress) was computed using two different least square methods. In this paper especially the relaxation time is given as a function of the applied radial reference strains.

According to several studies, results after reconstructive procedures in children are generally superior compared to those in adults. In the present retrospective study, 20 patients after reconstruction of one or more major nerves in the upper limb (median, ulnar, and radial nerves) were examined. At the time of operation, the patients' age was 8.9 years on the average, the follow-up time ranged between 29 and 173 months. In six cases the nerve lesion had been treated by direct nerve coaptation, in 14 patients a primary or secondary nerve grafting procedure had been applied. The results were classified according to Millesi's examination system, which takes several factors such as mobility, sensibility, skill, and force of the hand into account. Besides two patients, one after reconstruction of the median and ulnar nerves by grafts with significant destruction of the muscles in the lower arm, and the second one after primary coaptation of the median and ulnar nerves in the elbow region, all patients showed a hand function of more than 70% according to Millesi's scoring system. In patients older than ten years at the time of the reconstructive procedure, results were slightly worse than in younger individuals. Children up to ten years of age were nearly always able to move their hand and fingers normally. The results after nerve grafting were sometimes even superior to those after primary neurorrhaphy. Therefore, the present study supports the findings of previous authors describing the excellent regenerative potential of the growing peripheral nervous system. Furthermore, Millesi's scoring system better revealed some subtle differences in hand function when compared to other classifications.

Radiation-induced brachial plexus lesions are progressive and irreversible complications. Until now, there is no way to successful prevention and treatment of this problem. In our series, relief of pain could be achieved by neurolysis in some cases, but there was no recovery of sensory and motor function. In order to improve the vascularity and nerve tissue regeneration, we performed muscle or gliding tissue flaps after neurolysis in our department. Since 1975, 25 patients who developed radiation-induced plexopathy were treated in our department. We followed 18 patients to evaluate the benefits of our surgical intervention. None of the patients had improvement of their sensory or motor impairment. Relief of severe pain was achieved in 83% either by neurolysis only with or without muscle or gliding tissue flap. In some cases, paresis worsened postoperatively. We also observed a return of severe pain after the operation.

Pollicisation of a single long finger is the method of choice to treat congenital thumb aplasia or thumb hypoplasia. Using Millesi's scale for the functional analysis of the hand, we examined six patients treated in the years 1983 to 1994 in our service. Average age at the time of surgery was 2.4 years and the follow-up time was seven years on average. Of the six patients, four suffered from additional malformations of the ipsilateral arm. These anomalies required early surgical treatment and therefore delayed the pollicisation procedure. The results of the anatomical part of the examination ranged between 39 and 94% of the achievable value. The final results including sensibility, strength, and skills reached 11 to 50%. Development of skills and muscle strength in the operated hand was dependent on the follow-up time. Millesi's scale could be applied successfully in this special group of children with congenital malformation of hands.

Normal tendons and palmar aponeuroses from patients with carpal tunnel syndrome and tissues of the palmar aponeuroses from patients with Dupuytren’s contracture were subjected to biomechanical tests. Several parameters characterizing the viscoelastic load response of the tissues were investigated. The tissues from patients with Dupuytren’s contracture were classified according to their macroscopic and histological appearance into apparently normal palmar aponeuroses, thickened fibre bundles and contracture bands. There were biomechanical differences between the normal palmar aponeuroses and the apparently normal palmar aponeuroses indicating that biomechanical changes occur before thickening of fibres or cellular proliferation can be observed. Significant biomechanical changes occurred between apparently normal palmar aponeuroses and thickened fibre bundles.

Normal tendons, normal palmar aponeuroses and specimens from patients with Dupuytren's disease, namely apparently normal palmar aponeuroses and contracture bands were subjected to elastase and chondroitinase ABC digestion. Maximum Young's modulus, normalized hysteresis loop and residual elongation were determined before and after enzyme treatment. In normal tendons, normal and apparently normal palmar aponeuroses both normalized hysteresis loop and residual elongation increased significantly after elastase treatment, whereas the stiffness decreased. Normalized hysteresis loop and residual elongation display changes corresponding to the amount of digested elastin. The increased viscosity of untreated contracture bands containing less elastin, as compared to normal palmar aponeurosis, was not affected by elastase. Obviously, the elastic fibers in normal shape and distribution are responsible for maintaining an elastic status with a low viscous stress component. With the exception of contracture bands chondroitinase ABC caused a minor increase of residual elongation and as opposed to elastase a decrease of normalized hysteresis loop indicating an increased mobility of the tissue fibers.

Peripheral nerve trunks are viscoelastic tissues with unique mechanical characteristics. Tensile strength, which includes elastic limit and mechanical failure, concerns surgeons. This study shows that measurements of the load necessary to achieve certain elongations on specimens outside the body do not correspond with in situ measurements. The necessary load is influenced by the presence or absence of branches and by the amount of fibrosis. Because of transverse contraction, elongation beyond a certain limit substantially decreases intrafascicular volume, leading to increased intrafascicular pressure. Stress relaxation is effective only if the nerve repair site is maintained under constant tension. Its beneficial effect disappears after 10 minutes if the repaired nerve is returned to a relaxed state. Therefore, tension at the repair site should be minimized.

Grundlagen: Sobald die Diagnose einer kompletten Läsion des Plexus brachialis feststeht und Aussicht auf spontane Regeneration bei Vorliegen eines Schadens 1. oder 2. Grades auszuschließen ist, wird der Plexus brachialis freigelegt. Je nach dem Ausmaß des Schadens wird eine mikrochirurgische Neurolyse, eine Wiederherstellung der Kontinuität durch Nerventransplantation oder ein Nerventransfer durchgeführt, um Axone von Nerven außerhalb des Plexus brachialis in die distalen Stümpfe wichtiger Nerven des Plexus brachialis zu bringen. Je nach Ausmaß und Qualität der Regeneration werden im zweiten bzw. dritten Jahr nach der Freilegung des Plexus brachialis Ersatzoperationen ausgeführt, um die Funktion zu verbessern. Der entscheidende Punkt liegt darin, daß beide Operationen vom selben Team ausgeführt werden und vielfach bei der ersten Operation künftige Ersatzoperationen eingeplant werden.

For centuries, surgeons did not dare to touch peripheral nerves because they were afraid of “convulsiones”. Peripheral nerve repair was carried out “cum came”; the neighbouring structures wire sutured and indirect coaptation of the nerve stumps achieved. This changed in the late 19th century, when surgeons realised that they could perform a nerve repair by suturing the connective tissue of the nerve. So Hueter (1873) suggested anchoring the stitches in what he called “paraneurotic” tissue. From that moment, a development started which we can call the mechanical approach to nerve repair. The nerve was regarded as a telephone cable which has to be repaired as exactly as possible. An expression of this thinking is the fact that many surgeons believed in the so-called “primary healing of peripheral nerve” according to Schiff (1851). If a transected nerve was repaired immediately and very exactly, no Wallerian degeneration would occur and function would be restored immediately. The management of peripheral nerve defects was based on pure mechanical considerations. The main problem seemed to be to avoid dehiscence of the suture, so immobilisation of the adjacent joints in a flexed position was advised to give the axon sprouts a chance to cross the site of coaptation. After the site of repair had achieved sufficient tensile strength, the extensibility of the nerve tissue had to be exploited to make the nerve again long enough for the complete range of motion (Miiller, 1917 ; Baron and Scheiber, 1918). Babcock (1927) believed that in the median nerve a defect of 21 cm could be overcome. If one remembers that the length of the median nerve from the upper border of the latissimus dorsi muscle to the wrist joint is about 52 ems., this means that the remaining portions of the median nerve had to be elongated by 60%. Repairs of this kind were apparently not very successful because the so-called critical resection length came down to 5 to 8 ems. (Seddon, 1954; Wertheimer and Matthieu, 1949; Woodhall et al., 1956; Yahr and Beebe, 1959). 8 ems. is still 15% of the length of the median nerve in an adult patient. The remaining median nerve had to be elongated by 18% to fill the defect. This elongation is very close to the limit of the physical properties of a cadaver nerve. Sunderland and Bradley (1961) measured the limit of extensibility of cadaver median nerves as between 9 and 26%. It is true that elongation after nerve repair was achieved gradually and it was argued that, in a lengthen-