OBJECTIVETo observe the biomechanic properties of sciatic nerve at the suture site in rats following repairing.

METHODSThe right sciatic nerves of 40 white Sprague-Dawley 300-350 gm rats were exposed, cut and then repaired with 10-0 nylon sutures, laced in the epineurium. 0, 1, 3, 6 weeks after operation, the tensile strength of the sciatic nerves were measured, the data analyzed statistically.

RESULTSThe load-elongation curves for both the normal unoperated and operated nerves had the similar shape. The tensile strength of the 0 week was significant difference to 1, 3 and 6 weeks (P < 0.01). No significant difference was found among 1, 3 and 6 weeks.

CONCLUSIONThe tensile strength of the injured nerves are recovered in the first week and resistant in 6 weeks after repairing.

Animals ; Elasticity ; Male ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; physiology ; surgery ; Tensile Strength ; Time Factors

OBJECTIVEPresent study aimed at further comprehensive functional, histomorphometrical and immunohistochemical assessment of peripheral nerve regeneration using rat sciatic nerve transection model.

METHODSThe 10-mm rat sciatic nerve gap was created in rats. In control group nerve stumps were sutured to adjacent muscle and in treatment group the gap was bridged using an inside-out vein graft. In sham-operated group the nerve was manipulated and left intact. All animals underwent walking track analysis test 4, 8, and 12 weeks after surgery. Subsequently, muscle mass measurement was performed to assess reenervation, histological examination to observe the sciatic nerve regeneration morphologically and immunohistochemistry to detect Schwann cells using anti S-100. Results were analyzed using a factorial ANOVA with two between-subjects factors. Bonferroni test for pairwise comparisons was used to examine the effect of treatments.

RESULTSFunctional analysis of myelinated nerve fibers showed that nerve function improved significantly in the time course in treatment group. However, quantitative morphometrical analysis of myelinated nerve fibers showed that there was no significant difference between 8 and 12 weeks in treatment group. Muscle weight ratio was bigger and weight loss of the gastrocnemius muscle was ameliorated by inside-out vein grafting. The position of positive immunohistochemical reactions further implied that regenerated axons and Schwann cell-like cells existed after vein grafting was performed, and was accompanied by the process of myelination and structural recovery of regenerated nerves.

CONCLUSIONFunctional analysis of peripheral nerve repair is far more reliable than quantitative morphometrical analysis.

Animals ; Immunohistochemistry ; Male ; Nerve Regeneration ; Rats ; Recovery of Function ; S100 Proteins ; analysis ; Sciatic Nerve ; physiology ; surgery ; Veins ; transplantation

OBJECTIVETo evaluate the local effect of vascular endothelial growth factor (VEGF) on transected sciatic nerve regeneration.

METHODSSixty male white Wistar rats were divided into four experimental groups randomly (n equal to 15). In transected group the left sciatic nerve was transected and the stump was fixed to adjacent muscle. In treatment group the defect was bridged using a silicone graft filled with 10 microlitre VEGF. In silicone group the graft was filled with phosphate-buffered saline. In sham-operated group the sciatic nerve was exposed and manipulated. Each group was subdivided into three subgroups with five animals in each and nerve fibers were studied 4, 8 and 12 weeks after operation.

RESULTSBehavioral test, functional study of sciatic nerve, gastrocnemius muscle mass and morphometric indices confirmed a faster recovery of regenerated axons in VEGF group than in silicone group (P less than 0.05). In immunohistochemical assessment, reactions to S-100 in VEGF group were more positive than that in silicone group.

CONCLUSIONLocal administration of VEGF will improve functional recovery and morphometric indices of sciatic nerve.

Administration, Topical ; Animals ; Nerve Regeneration ; drug effects ; Rats ; Rats, Wistar ; Sciatic Nerve ; surgery ; Vascular Endothelial Growth Factor A

OBJECTIVE: To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury. METHODS: Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group. RESULTS: At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm ², which was significantly more than that in group A [(298.33±153.12) cells/mm ²] ( t=6.139, P<0.001). CONCLUSION The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.
Rats ; Animals ; Male ; Rats, Sprague-Dawley ; Polyesters ; Peripheral Nerve Injuries/surgery* ; Elastomers ; Urethane ; Sciatic Nerve/injuries* ; Carbamates ; Nerve Tissue ; Nerve Regeneration/physiology*

OBJECTIVETo explore the clinical characteristics and the effect of surgical therapy for shotgun injuries of the sciatic nerve.

METHODSFrom 1996 to 2000, 19 sciatic nerve injuries resulted from shotgun were observed. Among 19 cases of shotgun sciatic nerve wounds, the gluteal wound was in 2 cases, thigh wound in 15 cases, and knee wound in 2 cases. The firing distance was between 0.5-9 m. According to Shermen classification of shotgun injury, 4 cases belonged to type I injury, 11 cases type II, 4 cases type III. The time from injury to admission was between 2 months-14 months except 1 patient who underwent emergency operation 4 hours after injury, and 1 patient was treated with debridement and epineurial neurorrhaphy, 7 cases with nerve trunk grafting, 6 cases with nerve cable grafting, 4 cases with neurolysis, 1 case with arthrodesis of ankle.

RESULTSNineteen cases were followed-up for 0.8-3.5 years (mean, 19 months). The excellent and good nerve functional recovery was found in 52.6% according to MCRR.

CONCLUSIONSShotgun injuries of the sciatic nerve are very severe and complicated, and injuries in most patients were usually complicated by open fracture, vascular injury, soft-tissue loss and infection; the character of nerve injury was classified as 4-5 degree according to Sunderland Standard, nerve transfer is effective in the treatment of shotgun injuries of the sciatic nerve, but outcome is poor; the recovery of the sciatic nerve should be observed continually after injury; selecting correct initial treatment after injury, strict minimally invasive surgical procedure, physical therapy and reasonable preoperative and postoperative medication can improve the surgical results.

Adolescent ; Adult ; Follow-Up Studies ; Humans ; Male ; Patient Satisfaction ; Sciatic Nerve ; injuries ; surgery ; Treatment Outcome ; Wounds, Gunshot ; complications ; rehabilitation ; surgery

OBJECTIVETo summarize surgical treatments and their corresponding curative effects on sciatic nerve injuries.

METHODSSurgical treatments on sciatic nerve injury were performed in 28 patients from January 1990 to July 2000. The treatments included neurolysis, neurolysis plus partial nerve anastomosis, nerve anastomosis and nerve transplantation. The curative effect was evaluated according to Sunderland criteria.

RESULTSOf 28 cases, 22 patients were followed up with a follow-up period of 13 months to 5 years (average 30 months). Of 22 nerves, 7 were excellent, 5 good, 7 fair and 3 poor, with an excellence rate of 54.5%.

CONCLUSIONSThe fair results of sciatic nerve injury are related to its structural character. Surgical exploration should be performed if nerve function does not recover 3 months after primary operation and if Tinel's sign and electromyogram show no signs of nerve regeneration. Electrophysiological monitoring in the operation is useful in electing surgical methods and predicting the results of nerve anastomosis.

Adolescent ; Adult ; Anastomosis, Surgical ; Child ; Cohort Studies ; Female ; Follow-Up Studies ; Humans ; Injury Severity Score ; Male ; Middle Aged ; Nerve Regeneration ; physiology ; Neurosurgical Procedures ; methods ; Recovery of Function ; Retrospective Studies ; Sciatic Nerve ; injuries ; Sciatic Neuropathy ; etiology ; surgery ; Treatment Outcome

OBJECTIVETo evaluate the long-term outcome of Polytetrafluoroethylene (PTFE) conduit in nerve repair and to provide more evidence in view of its potential application to achieve a satisfactory functional recovery in clinical settings.

METHODSThirty-six Wistar rats had their right sciatic nerve transected and were repaired with either conventional microsuture technique (Control group, n=18) or a PTFE conduit with a gap of 5 mm left between the nerve stumps (PTFE group, n=18). At 6 and 9 months after the operation, electrophysiological assessment and measurement of gastrocnemius muscle weight were conducted and morphology of the regenerated nerves were studied with image analysis.

RESULTSAt 6 months postoperatively, the nerve conduction velocity recovered to 60.86% and 54.36% (P<0.05), and the gastrocnemius muscle weight recovered to 50.89% and 46.11% (P>0.05) in the Control group and the PTFE group respectively. At 9 months postoperatively, the recovery rate was 65.99% and 58.79% for NCV (P>0.05), and 52.56% and 47.89% for gastrocnemius muscle weight (P>0.05) in the Control group and the PTFE group respectively. Regenerated nerve fibers in the PTFE group had a regular round shape with no fragmentation, wrinkling or splitting of the myelin sheath. Image analysis revealed that the ratio of the myelin area to the total fiber area was larger at 9 months than at 6 months in both groups (P<0.01).

CONCLUSIONSMicroporous PTFE conduit may be an alternative for nerve repair allowing of guided nerve regeneration and functional recovery with no obvious adverse effect at long-term.

Animals ; Biocompatible Materials ; Male ; Microsurgery ; Myelin Sheath ; Nerve Regeneration ; Polytetrafluoroethylene ; Prostheses and Implants ; Rats ; Rats, Wistar ; Sciatic Nerve ; injuries ; pathology ; surgery ; Time Factors

OBJECTIVETo seek new method for the treatment of peripheral nerve injury.

METHODSIn rat model with sciatic nerve defect, chitosan-collagen film was sutured into conduit to bridge 5 mm, 10 mm nerve defects. Rats that underwent end-to-end anastomosis were taken as controls. General observation, electrophysiological study, histological study and image analysis were performed at 4, 8, 12 weeks postoperatively.

RESULTSIn 5 mm nerve defects, the quality of nerve regeneration was similar to that of the control group. For 10 mm nerve defect, nerve regeneration was inferior to that of the control group. Chitosan-collagen film obviously degraded at 12 weeks postoperatively.

CONCLUSIONSChitosan-collagen film conduit can be used to bridge peripheral nerve defect.

Animals ; Biocompatible Materials ; therapeutic use ; Chitin ; analogs & derivatives ; therapeutic use ; Chitosan ; Collagen ; therapeutic use ; Male ; Models, Animal ; Nerve Regeneration ; Rats ; Rats, Wistar ; Sciatic Nerve ; injuries ; physiology ; surgery

OBJECTIVETo test a nerve bridge substitute for peripheral nerve repair by tissue-engineering approach.

METHODSAn artificial nerve fabricated with a scroll of amnion derivative (ZQ membrane) and cultured autogenous Schwann cell was sutured to bridge sciatic nerve defect of 2.5 cm in length in rats. The specimens were assessed with tracking study, histology, electrophysiological technique, NF200, and synaptophysin-38 (SYP) immuno histochemical staining 3 months postoperatively.

RESULTSThe regenerated nerve sprouted 3 months after the operation. The regenerated nerve fibers were plentiful and could grow into the recipient nerve and target muscle's motor end plate (MEP) areas to reinnervate target muscle, and reconstruct function of nerve-muscle junction. Functional recovery could reach to 40%-60% of normal control. Nerve-muscle conduction velocity (N-MCV) arrived at 21.77 +/- 1.15 m/s.

CONCLUSIONSA tissue engineering material fabricated with a scroll of ZQ membrane and cultured autologous Schwann cell may be a useful substitute for nerve repair.

Amnion ; cytology ; Animals ; Cells, Cultured ; Female ; Male ; Nerve Regeneration ; physiology ; Rats ; Rats, Sprague-Dawley ; Schwann Cells ; cytology ; Sciatic Nerve ; injuries ; surgery ; Tissue Engineering ; methods

OBJECTIVETo investigate the possibility of bridging small peripheral nerve gap using a de-acetyl chitosan conduit.

METHODSThe sciatic nerves of right sides were cut at SD rats. They were divided into 5 Groups randomly; Group A: epineurium suture in situ (n = 24); Group B: biological conduit with a small gap for bridging the peripheral nerve (n = 24, with 5 mm gap); Group C: epineurium suture with distal stump rotated 180 degrees (n = 24); Group D: bridging the nerve by biological conduits with a small gap, but the distal stump rotated 180 degrees (n = 24, with 5 mm gap); Group E: biological conduit with a small gap for bridging the peripheral nerve with NGF (n = 24). Electrophysiological examination, histological examination and myelinated axon counting were applied after 2, 4, 6, 8 weeks after operation respectively.

RESULTSRegenerated nerve fibers were seen in the distal nerve segments of all 5 groups; The nerve conduction velocity of small gap group (group B, D) was faster than that of corresponding simple epineurium suture group (group A, C) at all 2, 4, 6, 8 week time point (P < 0.05). The myelinated axon counting of small gap group (group B, D) was faster than that of corresponding simple epineurium suture group (group A, C) at all 4, 6, 8 week time point (P < 0.01), and there was no statistically significant difference at 2 week time point.

CONCLUSIONThe repair effects of chitin conduit bridging peripheral nerve with small gap (5 mm) are better than that of epineurium suture directly, and possess the potential to substitute the epineurium suture.

Animals ; Biocompatible Materials ; Chitosan ; Male ; Nerve Regeneration ; Neurosurgical Procedures ; instrumentation ; methods ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; physiology ; surgery