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Objectives: This paper explores factors important for return to work (RTW) in people who have sustained a serious hand injury., Participants: Forty people aged 19-64, with a severe or major hand injury were recruited consecutively during 2005-2007., Methods: A self-administered and study specific questionnaire, including demographic data and standardised questionnaires for function, disability, daily occupations, health, quality of life, sense of coherence and several open questions was sent out by mail twelve months after injury. Open questions regarding RTW were also included., Results: The results showed that 27 people had returned to work within twelve months and 13 had not. Factors related to RTW and general work motivations were divided into individual factors, and factors related to the work environment and rehabilitation. The most prominent differences between the groups were individual factors, such as higher perceived disability, reduced hand function, and dissatisfaction with daily occupations resulting in a lower physical quality of life. The no RTW group had also more ward days (inpatient care) and lower sense of coherence., Conclusions: These findings support the idea that the RTW process can be more dependent on the person's own ability and motivation than on the severity of the hand injury. Suggestions for intervention and further studies are presented in the discussion.

Purpose: We investigated whether sutures could guide regeneration across bifurcated nerve defects and how the number of sutures influenced regeneration., Methods: Bilateral ten mm defects in the rat sciatic nerve were bridged by either two or six laps of longitudinal (8/0 polyglactin) sutures. Bilateral ten mm defects including the bifurcation of tibial and peroneal nerves were bridged by two laps to the tibial and four laps to the peroneal nerve on one side and vice versa on the other. Evaluation of tetanic force, weights of the gastrocnemius and caudal tibial muscles and morphometry of the nerves were performed at twelve weeks., Results: Simple defects bridged by six laps yielded a significantly greater number of myelinated axons compared to two laps. In the bifurcated defects a well defined two branched nerve structure was formed in all cases between the sciatic nerve and its peroneal and tibial branches. However, in the bifurcated model the tibial nerve attracted more axons than the peroneal irrespective of the number of suture laps., Conclusions: There is no simple correlation between the number of sutures and the number of regenerating axons but two suture laps may be insufficient for the repair of a rat sciatic nerve. Sutures supported reconstruction of new fascicles across bifurcated nerve defects.

Purpose: To compare the longitudinal suture model for bridging nerve defects with direct approximation under tension or with autologuos nerve grafting., Methods: Seven mm nerve defects in the rat sciatic nerve were repaired by either of these three methods. Evaluation was performed at twelve weeks by morphometry of the tibial nerve distal to the repair site and by weight of the gastrocnemius muscle, an indicator of target reinnervation., Results: The number of nerve fibers and myelin areas in the tibial nerve were similar for all repair methods as were the weight of the gastrocnemius muscle., Conclusions: Longitudinal sutures can be used to bridge short nerve defects and could be an alternative to nerve grafting., (Copyright 2004 IOS Press)

Purpose: To compare nerve regeneration in autologous detergent extracted and freeze-thawed muscle grafts and to electrophoretically characterize the grafts. Methods: Autologous acellular muscie grafts were created either by freeze/thawing or by detergent extraction and then used to bridge a 10 mm gap in rat sciatic nerve. The autologous grafts were compared with respect to protein content, using electrophoresis preimplantation, and axonal outgrowth, Schwann cell and macrophage content, using immunocytochemistry (neurofilaments, S-100 protein, ED 1 macrophages) at 5-20 days postimplantation. Results: The extracted muscle grafts were elastic, but the amount of several proteins was reduced and laminin was still present at a position of basal laminae of the muscle fibers. The freeze/thawed grafts were brittle and lacked elasticity, but resulted in minor changes in major proteins. The axons regenerated through both types of grafts (initial delay 6 days and rate 0.7-0.8 mm/day), which shrunk in length by 25%. There were no apparent differences with respect to Schwann cells and macrophages. Conclusions: The results suggest that detergent extracted muscle tissue, in which some basal lamina proteins remain but cells are removed, could present a new favourable option for nerve grafting.

The effects of granulation tissue exposure on regeneration of sensory axons after a test crush lesion in rat sciatic nerves were studied. Chromic catgut threads were applied subcutaneously in the back of rats. Three weeks later the surrounding granulation tissue was isolated and transposed to the sciatic or tibial nerve in the same rat. Immunocytochemical, light and electron microscopic evaluation of the isolated granulation tissue revealed numerous EDI and ED2 positive macrophages. After an additional three weeks the sciatic nerves were crushed and the axonal outgrowth lengths were measured by the pinch reflex test and by neurofilament staining 3 or 6 days later. The regeneration distances in the sciatic nerve exposed to granulation tissue were significantly longer compared with that of nerves to which only subcutaneous tissue was transposed. Thus, the nerve had become conditioned by the transposure of macrophage rich tissue. After the transposure macrophages were present close to the nerve at the time point of the test crush lesion, but no signs of degeneration or inflammation in the endoneurial space were observed. It was also found that the outgrowth lengths in the tibial nerve branch were consistently longer than in the peroneal branch of the sciatic nerve. It is concluded that granulation tissue, containing macrophages, can induce a conditioning effect in the sciatic nerve. We suggest that this effect is related to factors emanating from macrophages in the transposed tissue.

Regeneration distances were studied in nerves from vibration-exposed limbs. One hind limb of anaesthetized rats was attached to a vibration exciter and exposed to vibration (80 Hz/32 m/s2) for 5 h/day for 2 or 5 days. Seven days after the latest vibration period a 10-mm long nerve graft was taken from the vibrated sciatic nerve and sutured into a corresponding defect in the con-tralateral sciatic nerve and vice versa, thereby creating two different models within the same animal: (i) regeneration from a freshly transected unvibrated nerve into a vibrated graft and (ii) regeneration from a vibrated nerve into a fresh nerve graft (vibrated recipient side). Four, 6 or 8 days postoperatively (p.o.) the distances achieved by the regenerating axons were determined using the pinch reflex test. Two days of vibration did not influence the regeneration, but 5 days of vibration reduced the initial delay period and a slight reduction of regeneration rate was observed. After 5 days of vibration an increased regeneration distance was observed in both models at day 4 p.o. and at day 6 p.o. in vibrated grafts. This study demonstrates that vibration can condition peripheral nerves and this may be caused by local changes in the peripheral nerve trunk and in the neuron itself.

Macrophages have been regarded as important sources for different growth stimulating factors in nerve regeneration. The distribution of macrophages in the fibrin matrix, which is formed between the proximal and distal nerve stumps in silicone tubes [29], was investigated in rats. The sciatic nerves of rats were transected and the stumps were introduced into a silicone tube. After 3, 6, 14 or 28 days, the distribution of macrophages (ED1 and ED2), the cytokine Interleukin-1β (IL-1β), fibrin/fibrinogen, fibronec-tin, neurofilament and 5-100 protein was investigated using immunocytochemistry. The pattern of fibrin/fibrinogen, fibronectin, neurofilament and 5-100 protein was similar to previously published data [29]. The matrices at 3 and 6 days, as well as the later regenerate, contained both ED 1 and ED2 positive macrophages which was one of the cell types present. These cells were evenly distributed along the fibrin fibers or migrating cell columns. At the proximal and distal nerve stumps, macrophages were more abundant in the perineurial tissue which was close to the silicone tube, except for more macrophages in the distal part. IL-1β was also present, especially at 3 and 6 days and evenly distributed in the matrix, but the intensity of the staining decreased later. There was however no specific relation of ED1 or ED2 macrophage to the detected IL-1β. It is concluded that macrophages are trapped and present in the fibrin matrix formed between the proximal and distal nerve stumps at an early stage of the regeneration process and one of their products, IL-1β, was distributed in the matrix.

The presence of macrophages and the induction of c-jun protein and proliferation of non-neuronal cells were studied following implantation of silicone tubes with different diameters (i.e. 0.8 or 1.6 mm) around the rat sciatic nerve. Three days after implantation, numerous EDI and ED2 positive macrophages could be observed around the nerve beneath the 1.6 mm tubes. Some EDI and ED2 positive macrophages were also present in the endoneurium. In contrast, there were numerous EDI and ED2 positive macrophages in the endoneurium beneath the tube and distally in nerves surrounded by the 0.8 mm tube. In these experiments, there was also a massive induction of c-jun protein and DNA synthesis in non-neuronal cells, as visualised by c-jun and BrdU antibodies respectively (e.g. a response similar to that observed after a crush lesion). Such activated cells, albeit few, were also present in the endoneurium beneath the tube of nerves with a 1.6 mm tube, but not distal to the tube in the endoneurium. At 7 days, the responses were somewhat amplified but essentially the same as at 3 days. The results showed that the large diameter implants, which do not cause axonal damage, as does the small diameter tube, but result in conditioning of the nerve [4], induced invasion of macrophages around the nerve and activation of some cells in the endoneurium beneath the tube. We suggest that cell activation is caused by factors released from macrophages and that endoneurial cell activation is important for the conditioning of the nerve by the silicone tube implant.

The silicone chamber model for nerve regeneration is suitable to test the effects of exogenous agents or surgical manipulations on nerve regeneration. The total 16-day regeneration period used in this model makes it possible to analyze the effects of certain manipulations on the sequential advancement of the individual cellular components (circumferential perineurial-like cells, vessels, Schwann cells, axons, and myelin) into the chamber fibrin matrix. In the present study we compared the effects on cellular migration of a 7 day delayed chamber repair vs. chamber repair immediately after transection (control chambers) of the rat sciatic nerve. Regeneration was evaluated with light and electron microscopic techniques. Chambers implanted after a delay of 7 days had a statistically significant more advanced migration of vessels, Schwann cells, and axons from the proximal nerve stump and also a significantly increased vascular density as compared to control chambers. We conclude that a 7 day delayed nerve repair stimulates nerve regeneration in this specific silicone chamber model.

Matrix formation within silicone tubes of different geometries implanted between the stumps of the transected rat sciatic nerve was studied. A matrix, composed of longitudinally oriented fibrin strands containing fibronectin, was formed within one day. The matrix then increased in size. The matrix contained macrophages and other inflammatory cells. Matrix size could be increased if the diameter of the tube was increased or if holes were made in the implanted tube. In contrast, matrix diameter decreased if the tube length was increased or if circulation was compromised in the inserts. The results suggest that the size, orientation and cellular components of the matrix have profound effects on the regenerative response of the transected nerve.

The projection of regenerating axons and the specificity of motor reinnervation were studied after repair of the transected rat sciatic nerve with Y-tunnelled silicone chambers. This geometry was used experimentally to face either the proximal tibial or peroneal fascicle with two distal fascicular options usually the distal peroneal and tibial fascicle. A 4 mm gap separated the proximal and distal fascicles. Four weeks after the repair, preferential motor reinnervation could be demonstrated and there were always more axons projecting towards the distal homonymous fascicle. In contrast, if the distal stumps were disconnected from the target no fascicle specific projection of axons was observed. This was true even if segments from the median and ulnar nerve were used to replace either the distal tibial or peroneal segments. It appeared as though the size and not the type of fascicle determined the number of attracted axons. The results suggest that there is no fascicle specific guidance of regenerating nerve fibers.