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- Lutz, Barbara, 1960-, et al.
(författare)
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Morphological and functional evaluation of leg-muscle reinnervation after coupler coaptation of the divided rat sciatic nerve
- 2005
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Ingår i: Microsurgery. - : Wiley. - 0738-1085 .- 1098-2752. ; 25:3, s. 235-240
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Tidskriftsartikel (refereegranskat)abstract
- Mechanical couplers are successfully used for microvascular venous anastomoses. The advantages include a simple and fast technique and a high patency rate. Couplers offer a secluded coaptation site, and might also be of use in peripheral nerve repair. The present study was designed to investigate coupler coaptation of the rat sciatic nerve, evaluating the number and locations of motor and sensory neurons projecting to the selected muscles as well as stimulation-induced muscle contraction force. Adult rats underwent either suture or coupler repair after left sciatic nerve transection. In all rats, the experimental side was compared to the healthy right side. Evaluation after 20 weeks included retrograde labeling of motoneurons and dorsal root ganglion neurons projecting to the tibial anterior muscle and to the tibial posterior muscle, histology, muscle contraction force (tibial anterior muscle and gastrocnemius muscle), and a pinch reflex test. The results show that the suture and the coupler groups did not differ significantly regarding the examined parameters, except for discrete signs of nerve compression at the coaptation site after coupler repair due to fibrous tissue ingrowth. However, this did not impair axonal regeneration. Importantly, axonal outgrowth from the repair site to the surrounding tissue was not observed after coupler coaptation, but it was observed after suture repair. These results suggest that couplers may be of value for repair of nerves in adjacency to avoid axonal crisscrossing between nerves during regeneration. © 2005 Wiley-Liss, Inc.
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- Lutz, Barbara, 1960-
(författare)
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Repair of divided peripheral nerves : experimental studies in rabbit and rat
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this thesis was to provide new knowledge, through experimental studies, that may contribute to an improvement of the results after microsurgical peripheral nerve repair in patients.An adequate function of the human body depends, among other things, on a correctly functioning peripheral nervous system. Peripheral nerve injuries may impair the motor and sensory function of muscles, the proprioceptive joint control, the cutaneous sensibility, and the autonomic control of the skin, which can result in severe dysfunction of e.g. an extremity. The worst grade- of nerve injury is the division of an entire nerve. In the ideal case, the divided nerve can be sutured so that the distal and proximal nerve stumps are brought together. When peripheral nerve tissue has been lost at the site of injury, a direct repair is not possible. In such cases, the use of nerve grafts to bridge the defect, and/or suture of the distal nerve stump to an entirely different donor nerve is necessary to restore some function. Both types of such nerve repair, however, produce new sequelae due to loss of function of the nerves used for repair. To avoid such donor nerve morbidity, two different types of repair, end-to-end coaptation to part of a healthy donor nerve and end-to- side neurorrhaphy were investigated experimentally.Neurotomy studies in the rabbit showed that use of 1/3 of a donor nerve (ulnar nerve) for reinnervation of an agonistic recipient nerve (median nerve) results in a useful muscle function with negligible donor nerve morbidity.In the rat, end-to-side neurorrhaphy of a recipient nerve (median nerve) to an agonistic donor nerve (ulnar nerve) turned out to give a useful muscle function without causing donor nerve morbidity. After end-to-side neurorrhaphy, reinnervation of the recipient nerve stump was executed by collateral sprouting from intact donor nerve axons. The regeneration of sensory axons was numerically superior to the regeneration of motor axons. Altogether, however, good results after end-to-side neurorrhaphy are not predictable.Both types of nerve repair (end-to-side neurorrhaphy and partial end-to-end neurorrhaphy) give better results with respect to reinnervation of a nerve to a simple muscle target than with respect to reinnervation of a nerve to a complex muscle target.In the ideal situation, after conventional end-to-end nerve suture, nerve repair results in an axonal regeneration that restores muscle function as well as cutaneous sensibility and autonomous function. However, a completely normal function is usually not achieved due to e.g. aberrant axonal regeneration that results in a nerve-target mismatch. One of the causes for aberrant regeneration is axonal criss-crossing between fascicles in adjacency. Hence, barriers of different materials were tested in the rat to see if interfascicular axonal criss-crossing can be counteracted.Three materials - a pedicle fat flap, Integra®, and non-vascularized autologous fasciawere used as barriers between the peroneal and the tibial fascicles in rats. The results showed that all three barriers improved axonal alignment after sciatic nerve transection and fascicular end-to-end repair. The pedicle fat flap was the most valuable barrier.Finally, coaptation of the divided rat sciatic nerve with the aid of couplers, normally used for microvascular anastomoses, was evaluated as a method to hinder erratic centrifugal axon growth. The results showed that couplers provided a secluded coaptation site avoiding aberrant axonal sprouting to the surroundings. However, a minor nerve compression was evident.Altogether, these results show that the microsurgical repair of nerve transections can be improved a bit further. However, the future developments in this area are likely to occur at the molecular level.
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- Lutz, Barbara, 1960-
(författare)
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Structural and functional regeneration of muscle-related axons after transection and repair of the rat sciatic nerve using nonvascularized autologous fascia as a barrier between tibial and peroneal nerve fascicles
- 2004
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Ingår i: Journal of reconstructive microsurgery. - : Georg Thieme Verlag KG. - 0743-684X .- 1098-8947. ; 20:8, s. 637-644
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Tidskriftsartikel (refereegranskat)abstract
- Aberrant reinnervation of target organs caused by misdirected axonal growth at the repair site is a major reason for the poor functional outcome usually seen after peripheral nerve transection and repair. This study investigates whether the criss-crossing of regenerating rat sciatic nerve axons between tibial and peroneal nerve fascicles can be reduced by using non-vascularized autologous fascia as a barrier.The left sciatic nerve was transected and repaired at midthigh as follows: epineurialy sutures (Group A); fascicular repair of tibial and peroneal nerve fascicles (Group B); fascicular repair of tibial and peroneal nerve fascicles separating the two fascicles by non-vascularized autologous fascia (Group C). In the control Group D, only the left tibial fascicle was transected and repaired. Five months postoperatively, the outcome of regeneration was evaluated by histology, by retrograde tracing, and by assessment of the contraction force of the gastrocnemius and tibial anterior muscles. The tracing experiments showed that muscle reinnervation was less abnormal in Group C than in Groups A and B. However, muscle contraction force was not better in Group C than in Groups A and B. With respect to the peroneal nerve innervated muscle, the contraction force in Group C was significantly lower than in Group B. The histologic picture indicated that this inferior result in Group C was due to nerve compression caused by fibrotic scar tissue at the site of the fascia graft.Results of this study show that a non-vascularized autologous fascial graft used as a barrier between two sutured nerve fascicles in adjacency reduces criss-crossing of regenerating axons between the fascicles, but causes significant nerve compression.
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- Lutz, Barbara, 1960-
(författare)
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The role of a barrier between two nerve fascicles in adjacency after transection and repair of a peripheral nerve trunk
- 2004
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Ingår i: Neurological Research. - : Informa UK Limited. - 0161-6412 .- 1743-1328. ; 26:4, s. 363-370
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Tidskriftsartikel (refereegranskat)abstract
- Aberrant reinnervation of target organs caused by misdirected axonal growth at the repair site is a major reason for the poor functional outcome usually seen after peripheral nerve transection and repair. The following two studies investigate whether criss-crossing of regenerating rat sciatic nerve axons between tibial and peroneal nerve fascicles can be reduced by using a barrier at the coaption site. The left sciatic nerve was transected and repaired at mid-thigh as follows: epineural sutures (group A, A-II), fascicular repair of tibial and peroneal nerve fascicles (group B, B-II), fascicular repair of tibial and peroneal nerve fascicles separating the two fascicles with a pedicled fat flap (group C), Integra® (group D) or non-vascularized autologous fascia (group C-II). In the control groups E and D-II, only the left tibial fascicle was transected and repaired. Four and 5 months postoperatively, the outcome of regeneration was evaluated by histology, by retrograde tracing, and by assessment of the muscle force of the gastrocnemius and tibial anterior muscles. The tracing experiments showed that specificity of muscle reinnervation significantly improved when a barrier was employed, which significantly or clearly improved muscle twitch tension in groups C and D. However, muscle contraction force was not better when fascia was used as barrier. The histological picture indicated that this inferior result in group C-II was due to nerve compression caused by fibrotic scar tissue at the site of the fascia graft. Results of this study show that a pedicle fat flap and Integra® used as barrier significantly prevent aberrant reinnervation between two sutured nerve fascicles in adjacency resulting in improved motor recovery in rats. Non-vascularized autologous fascia however, reduces also criss-crossing of regenerating axons between the fascicles, but causes significant nerve compression.
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