| Objectives Through animal experiment, comparing direct epineurial anastomosis method, epineurial small gap anastomosis method, and vascular nerve anastomosis method, pros and cons of three nerve anastomosis methods, as a reference for clinical application.Method 72 female SD rats, randomly divided into 3 experiment groups, that is direct epineurial anastomosis method group (control group), epineurial small gap anastomosis method group (experiment group A), and vascular nerve anastomosis method group (experiment group B), each group had 24 rats. Every rats of each group were done in lateral position, anatomically the experimental side was mid-thigh sciatic Nerve, transverse cut, which is in control group the broken nerve was sutured directly; in experiment group A reveal two epineurial stump, pull out and cut off the nerve fibers about 1 mm, then used 11-0 microsurgery suture at 2 mm from outer space; in experiment group B cut off the nerve and at the same time took out 4 mm of femoral vein, then put the two sets of nerve stump 1 mm inside the vein tube cavity,left 2 mm gaps between two side, used 11-0 microsurgery sutures fixed the vein on both ends of the nerve membrane; post-op, the skin of each group's rats were sutured and they were feeding. At 2,4,8 weeks post-op, took out 8 rats from each groups as mentioned above, examined the anastomotic pattern (under microscope), gastrocnemius' biggest contracture, gastrocnemius muscle wet weight, Myelinated fiber counts of sciatic nerve, SEM observation of ultrastructure as well as histological observation as indicators, made a statistical analysis.Results control group,2 weeks post-op, the adhesion between the anastomosis site and the surrounding tissue was severer, scar tissue proliferates, neuroma formation was not obvious, progress over time.4 and 8 weeks post-op, the anastomosis' adhesion was milder, scar tissue proliferation lesser, there was neuroma formation; Experiment group A, in all observation time, no obvious adhesion formation can be seen, scar tissue proliferation become severer, no neuroma formation, often can be seen swollen at the distal and proximal of anastomosis site, outer layer become thinner; Experiment group B, in all observation time, no obvious adhesion formation can be seen, a certain degree of scar tissue proliferation can be seen around the venous bridge,the tube that connected the vein and the nerve is usually become thinner. The wet weight of the gastrocnemius muscle of each group has no significant differences (p> 0.05). Post-op 2 and 4 Weeks, The maximum tetanic contraction of each group's gastrocnemius muscle has no significant recovery (p> 0.05); Post-op 8 weeks, both control group and experiment group I's grastrocnemius muscle maximum tetanic contraction has no significant recovery (p> 0.05), on average it is better from experiment group B (p< 0.05).2 weeks post-op,each group has extensive necrosis of myelinated nerve fibers,it's very rare to find a new myelinated nerve fibers formation.4 weeks post-op, From total myelinated nerve fibers of each group, there is no significant difference between the total number in control group and experiment group A (p> 0.05), but they are better than experiment group B (p< 0.05); 8 weeks post-op,most of each group's myelinated nerve fibers have restored compare to earlier time,and no significant difference from the degree of restoration (p> 0.05).Under SEM observation, post-op 2 weeks, each group showed mainly the damaged myelinated nerve fibers,rare in the formation of new myelin; post-op 4 weeks,each group has new and damaged myelinated nerve fibers which is the new ones mainly seen,the nerve fibers' diameter are smaller, disarrangement, morphology is also irregular,nerve myelin is also thinner, each group showed no significant difference at the new myelinated nerve fibers'size and the myelin sheath thickness (p> 0.05); post-op 8 weeks, each group showed mostly the new myelinated nerve fibers, the damaged ones become lesser, the myelinated nerve fibers' distribution is regular at this point, the diameter is bigger than before, morphology is regular, the myelin sheath thickness has increased,the layers are clearer than before, There is no significant differences between the new myelinated nerve fibers size and myelin sheath thickness of each group (p > 0.05). Histology observation, control group post-op 2 weeks,outside the anastomosis site can see connective tissue hyperplasia,contains rich of blood vessels formation,within the anastomosis site can see the damaged myelinated nerve afibers,myelinolysis,crack,axons disappeared, tissues disorder,and there is some swollen myelinated nerve at the anastomosis site,can not see any myelinated nerve fibers pass through the anastomosis site. post-op 4 weeks, the damaged myelinated nerve fibers decrease dramatically, new myelin fibers formation, and also pass through the anastomosis site, Some of new fibers protruding outward through the outer membrane of anastomosis. Post-op 8 weeks,the central part of the distal anastomosis site shows scar tissue formation,accompanied by the new myelinated nerve fibers, the total of the myelinated nerve fibers formed has increased, Epineurial connective tissue proliferation, makes the nerve circumference larger, epineurial usually disappear, In turn by the overflow of nerve fibers and hyperplasia of connective tissue surrounding the formation of neuroma; Experimental group A, post-op 2 weeks, Inner side of epineurial anastomosis generates a small amount of connective tissue, the hollow formation inside the nerve lumen, continuation, the nerve myelinated fibers grow neatly along the lumen, but has not reached the distal part of the nerve bundle, post-op 4 weeks, scar tissue at the anastomosis site wall become more prominent, thicker, Scar surrounded the internal cavity has been filled with the growth came from the proximal myelinated nerve fibers, post-op 8 weeks, scar tissue at the anastomosis site wall become thicker than before, within the scar there is new blood vessels formation, the density of the myelinated nerve fibers within the scar lumen increased, arranged closely, regularly. Experiment group B, post-op 2 weeks, scar tissue formation within the wall of the venous bridge, scarring of the wall as well, a broad scar hyperplasia sometimes can be seen near distal venous anastomosis on both sides, impede or blockade the nerve fibers passing through, post-op 4 weeks, the vicinity of the scar tissue inside the wall is become more apparent, the wall is blurred can not been identified, the myelinated nerve fibers within the lumen increased compare to before, and the scattered scar tissue staggered bypass, post-op 8 weeks, scartissue outside the anastomosis site is thicker, and new blood vessels formation inside the scar, the density of the myelinated nerve fibers within the scar lumen increased than before.Conclusion The traditional direct repairment method is better than vascular nerve anastomosis method and epineurial small gap anastomosis method. |
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