OBJECTIVETo study the use of a nerve ''bypass'' graft as a possible alternative to neurolysis or segmental resection with interposition grafting in the treatment of neuroma-in-continuity.

METHODSA sciatic nerve crush injury model was established in the Sprague-Dawley rat by compression with a straight hemostatic forceps. Epineurial windows were created proximal and distal to the injury site. An 8-mm segment of radial nerve was harvested and coaptated to the sciatic nerve at the epineurial window sites proximal and distal to the compressed segment (bypass group). A sciatic nerve crush injury without bypass served as a control. Nerve conduction studies were performed over an 8-week period. Sciatic nerves were then harvested and studied under transmission electron microscopy. Myelinated axon counts were obtained.

RESULTSNerve conduction velocity was significantly faster in the bypass group than in the control group at 8 weeks (63.57 m/s+/-5.83 m/s vs. 54.88 m/s+/-4.79 m/s, P<0.01). Myelinated axon counts in distal segments were found more in the experimental sciatic nerve than in the control sciatic nerve. Significant axonal growth was noted in the bypass nerve segment itself.

CONCLUSIONNerve bypass may serve to augment peripheral axonal growth while avoiding further loss of the native nerve.

Animals ; Male ; Neural Conduction ; Neuroma ; surgery ; Peripheral Nerves ; transplantation ; ultrastructure ; Peripheral Nervous System Neoplasms ; surgery ; Rats ; Rats, Sprague-Dawley

BACKGROUNDPeripheral nerve injury causes a high rate of disability and a huge economic burden, and is currently one of the serious health problems in the world. The use of nerve grafts plays a vital role in repairing nerve defects. Acellular nerve grafts have been widely used in many experimental models as a peripheral nerve substitute. The purpose of this study was to test the biomechanical properties of acellular nerve grafts.

METHODSThirty-four fresh sciatic nerves were obtained from 17 adult male Wistar rats (age of 3 months) and randomly assigned to 3 groups: normal control group, nerve segments underwent no treatment and were put in phosphate buffered saline (pH 7.4) and stored at 4°C until further use; physical method group, nerve segments were frozen at -196°C and then thawed at 37°C; and chemical method group, nerve segments were chemically extracted with the detergents Triton X-200, sulfobetaine-10 (SB-10) and sulfobetaine-16 (SB-16). After the acellularization process was completed, the structural changes of in the sciatic nerves in each group were observed by hematoxylin-eosin staining and field emission scanning electron microscopy, then biomechanical properties were tested using a mechanical apparatus (Endura TEC ELF 3200, Bose, Boston, USA).

RESULTSHematoxylin-eosin staining and field emission scanning electron microscopy demonstrated that the effects of acellularization, demyelination, and integrity of nerve fiber tube of the chemical method were better than that of the physical method. Biomechanical testing showed that peripheral nerve grafts treated with the chemical method resulted in some decreased biomechanical properties (ultimate load, ultimate stress, ultimate strain, and mechanical work to fracture) compared with normal control nerves, but the differences were not statistically significant (P > 0.05).

CONCLUSIONNerve treated with the chemical method may be more appropriate for use in implantation than nerve treated with the physical method.

Animals ; Biomechanical Phenomena ; Male ; Microscopy, Electron, Scanning ; Peripheral Nerve Injuries ; therapy ; Peripheral Nerves ; physiology ; ultrastructure ; Rats ; Rats, Wistar ; Sciatic Nerve ; physiopathology ; ultrastructure ; Tissue Engineering

We reviewed dinical, histological and ultrastructural findings of 124 cases of sural nerve biopsy specimens to delineate the trends of peripheral nerve diseases in our institute. Eighty-one were men and 43 were women. We categorized them into five groups: specific diagnosis (66 cases, 53.2%), axonal degeneration type (47 cases, 37.9%), demyelinating type (4 cases, 3.2%), mixed axonal degeneration-demyelinating type (6 cases, 4.8%) and normal (1 case, 0.9%). Cases with specific diagnosis included 21 inflammatory demyelinating polyneuropathy (15 chronic inflammatory demyelinating polyradiculoneuropathy, 6 Guillain-Barre disease), 13 hereditary motor and sensory neuropathy (7 Charcot-Marie-Tooth type I, 6 Charcot-Marie-Tooth type II), 10 vasculitis, 6 toxic neuropathy, 4 leprosy, 3 diabetic neuropathy, 2 alcoholic neuropathy, 1 Fabry's disease and other specific diseases (5 cases). In our cases, the proportion of specific diagnoses was higher, while the proportion of demyelinating peripheral neuropathies and normal were lower than those of Western series. The results of this study indicate that 1) a dose clinicopathologic correlation is important to make a precise diagnosis of peripheral nerve biopsy, 2) Biopsy under strict indication may reduce unnecessary histologic examination, 3) There is no difference in disease pattern of peripheral neuropathy between Western people and Koreans.
Adult ; Biopsy ; Charcot-Marie-Tooth Disease/pathology ; Demyelinating Diseases/pathology ; Fabry Disease/pathology ; Female ; Hereditary Motor and Sensory Neuropathies/pathology ; Human ; Korea ; Leprosy/pathology ; Male ; Microscopy, Electron ; Nerve Fibers, Myelinated/pathology ; Peripheral Nerves/ultrastructure ; Peripheral Nerves/pathology ; Peripheral Nervous System Diseases/pathology* ; Peripheral Nervous System Diseases/microbiology ; Polyradiculoneuropathy, Chronic Inflammatory Demyelinating/pathology ; Sural Nerve/ultrastructure ; Sural Nerve/pathology*