Despite advances in surgical techniques for peripheral nerve repair, functional restitution remains incomplete. The timing of surgery is one factor influencing the extent of recovery but it is not yet clearly defined how long a delay may be tolerated before repair becomes futile. In this study, rats underwent sciatic nerve transection before immediate (0) or 1, 3, or 6 months delayed repair with a nerve graft. Regeneration of spinal motoneurons, 13 weeks after nerve repair, was assessed using retrograde labeling. Nerve tissue was also collected from the proximal and distal stumps and from the nerve graft, together with the medial gastrocnemius (MG) muscles. A dramatic decline in the number of regenerating motoneurons and myelinated axons in the distal nerve stump was observed in the 3- and 6-months delayed groups. After 3 months delay, the axonal number in the proximal stump increased 2–3 folds, accompanied by a smaller axonal area. RT-PCR of distal nerve segments revealed a decline in Schwann cells (SC) markers, most notably in the 3 and 6 month delayed repair samples. There was also a progressive increase in fibrosis and proteoglycan scar markers in the distal nerve with increased delayed repair time. The yield of SC isolated from the distal nerve segments progressively fell with increased delay in repair time but cultured SC from all groups proliferated at similar rates. MG muscle at 3- and 6-months delay repair showed a significant decline in weight (61% and 27% compared with contra-lateral side). Muscle fiber atrophy and changes to neuromuscular junctions were observed with increased delayed repair time suggestive of progressively impaired reinnervation. This study demonstrates that one of the main limiting factors for nerve regeneration after delayed repair is the distal stump. The critical time point after which the outcome of regeneration becomes too poor appears to be 3-months.
The purpose of this study was to measure the functional range of motion of the finger joints needed to perform activities of daily living. Using the Sollerman hand grip function test, 20 activities were assessed in ten volunteers. The active and passive range of motion was measured with a computerized electric goniometer. The position of each finger joint was evaluated in the pre-grasp and grasp positions. The functional range of motion was defined as the range required to perform 90% of the activities, utilizing the pre-grasp and grasp measurements. The functional range of motion was 19°-71°, 23°-87°, and 10°-64° at the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints, respectively. This represents 48%, 59%, and 60% of the active motion of these joints, respectively. There was a significant difference in the functional range of motion between the joints of the fingers, with the ulnar digits having greater active and functional range. The functional range of motion is important for directing indications for surgery and rehabilitation, and assessing outcome of treatment.
Introduction:Previously we showed that a fibrin glue conduit with human mesenchymal stem cells
(hMSCs) and cyclosporine A (CsA) enhanced early nerve regeneration. In this study long
term effects of this conduit are investigated.Methods:In a rat model, the sciatic nerve was repaired with fibrin conduit containing fibrin
matrix, fibrin conduit containing fibrin matrix with CsA treatment and fibrin conduit
containing fibrin matrix with hMSCs and CsA treatment, and also with nerve graft as
control.Results:At 12 weeks 34% of motoneurons of the control group regenerated axons through the
fibrin conduit. CsA treatment alone or with hMSCs resulted in axon regeneration of 67%
and 64% motoneurons respectively. The gastrocnemius muscle weight was reduced in the
conduit with fibrin matrix. The treatment with CsA or CsA with hMSCs induced recovery of
the muscle weight and size of fast type fibers towards the levels of the nerve graft
group.Discussion:The transplantation of hMSCs for peripheral nerve injury should be optimized to
demonstrate their beneficial effects. The CsA may have its own effect on nerve
regeneration.
Background:The exact role of proximal and distal nerve transfers in reconstruction strategies of brachial plexus injury remains controversial. We compared proximal with distal nerve reconstruction strategies in a rat model of brachial plexus injury.Methods:In rats, the C6 spinal nerve with a nerve graft (proximal nerve transfer model, n = 30, group A) and 50% of ulnar nerve (distal nerve transfer model, n = 30, group B) were used as the donor nerves. The targets were the musculocutaneous nerve and the biceps muscle. Outcomes were recorded at 4, 8, 12, and 16 weeks postoperatively. Outcome parameters included grooming test, biceps muscle weight, compound muscle action potentials, tetanic contraction force, and axonal morphology of the donor and target nerves.Results:The axonal morphology of the 2 donor nerves revealed no significant difference. Time interval analysis in the proximal nerve transfer group showed peak axon counts at 12 weeks and a trend of improvement in all functional and physiologic parameters across all time points with statistically significant differences for grooming test, biceps compound action potentials, tetanic muscle contraction force, and muscle weight at 16 weeks. In contrast, in the distal nerve transfer group, the only statistically significant difference was observed between the 4 and 8 week time points, followed by a plateau from 8 to 16 weeks.Conclusions:Outcomes of proximal nerve transfers are ultimately superior to distal nerve transfers in our experimental model. Possible explanations for the superior results include a reduced need for cortical adaptation and higher proportions of motor units in the proximal nerve transfers.
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