OBJECTIVETo study orientation remodeling without stress in bone harvest chamber.

METHODSThe bone harvest chamber (BHC) methodology is adopted in this study. Five female Japanese white rabbits were allowed unrestricted activity. The bone harvest chamber was a cylindrical Ti implant body with a transverse 1 mm wide canal for bone ingrowths. Retrieval of the contents of the canal was allowed with minimal disturbance to the surrounding bone or outer cylinder. After bone harvest chambers were implanted into the tibia of rabbits for 8 weeks, the chambers were considered to be osseointegrated with the bone. After harvested, the tissue were fixed and decalcified, then embedded in paraffin. Each rabbit was put into surgical operation 4 times for 4 stages: vacant for the first time; the tissue were cut into longitudinal sections at the second and third stages; harvesting tissues were cut into transverse sections at the fourth stage. Directional analysis: the standard deviation of the orientation of cell nucleus in each section was used as statistics, the difference between longitudinal section and transverse section were analyzed.

RESULTSOf the tissue into bone harvest chamber, directionality of cells arranged was more significantly on longitudinal section than on transverse section and there was statistical ignificecne.

CONCLUSIONUnder the no-stress circumstance of BHC bone remodeling showed directivity. Stress is not the direct leading signal about bone reconstitution. The structure of BHC might be related to orientation remodeling, which suggests that the relationship between orientation and stress is mediated by blood vessel. The effect of stress may be to affect vessel distributing in some orietation.

Animals ; Biomechanical Phenomena ; Cell Culture Techniques ; instrumentation ; methods ; Cells, Cultured ; Female ; Osteocytes ; chemistry ; cytology ; Rabbits ; Tibia ; chemistry ; cytology

Objective To summarize our experience with intraoperative neural electrophysiological monitoring during spinal cord surgery. Methods The clinical data of 11 patients undergoing spinal cord surgery with intraoperative neural electrophysioiogical monitoring were retrospectively reviewed, and the monitoring was performed by recording the motor-evoked potential (MEP), somatosensory evoked potential (SEP), and evoked electromyography (EMG). Results Subtotal resection of the intramedullary cystic lesion was performed in 1 case and partial resection of the intramedullary tumor in another. In 9 cases of tethered spinal cord syndrome, obvious improvement was obtained in 8 cases, and the other 1 case showed no obvious changes in the symptoms after the operation. In all the 11 cases, the spinal cord remained intact and its function was totally preserved without damage of the eonus medullaris or the cauda equine. Conclusion Combined monitoring of MEP, SEP, and evoked EMG during spinal cord surgery is useful for protecting the spinal cord and the nerves roots, and may enhance the detection of the tethered tissue and ensure better safety of operations.