Objective To investigate the promotion effect of neurotropic reinnervation with chemically extracted acellular nerve allograft. Methods The sciatic nerves of 5 healthy adult SD rats, regardless of gender and weighing 270-300 g, were collected to prepare chemically extracted acellular nerve allograft. Eighteen healthy adult Wistar rats, regardless of genderand weighing 300-320 g, were made the model of left sciatic nerve defect (10 mm) and randomly divided into 2 groups: autograft (control group, n=9) and allograft group (experimental group, n=9). The defects were bridged by acellular nerve allograft in experimental group and by autograft by turning over the proximal and distal ends of the nerve in control group. At 3 months after transplantation, dorsal root ganglion (DRG) resection operation was performed in 6 rats of 2 groups. At 3 weeks after operation, the sural nerves were harvested to calculate the misdirection rate of nerve fibers with pathological staining and compute-assisted image analysis. Cholinesterase staining and carbonic anhydrase staining were performed in the sural nerve of 3 rats that did not undergo DRG resection at 3 months. Results The results of chol inesterase staining and carbonic anhydrase staining showed that experimental group had less brown granules and more black granules than control group. After DRG resection, count of myelinated nerve fiber were 4 257 ± 285 in the experimental group and 4 494 ± 310 in the control group significant (P lt; 0.05). The misdirection rate was 2.27% ± 0.28% and 7.65% ± 0.68% in the experimental group and in the control group respectively, showing significant difference (P lt; 0.05). Conclusion Chemically extracted acellular nerve allograft can not only act as a scaffold in the period of nerve defects repair, but markedly enhance the effects of neurotropic reinnervation.
Objective To investigate the effect of removing the implanted plate-rod system for scol iosis (PRSS) on maintaining scol iosis curve correction and preserving spinal mobil ity in patients with scol iosis. Methods From June 1998 to February 2002, 119 cases of scol iosis were treated with the implant of PRSS, which was removed 26-68 months later (average46.8 months). Complete follow-up data were obtained in 21 patients, including 6 males and 15 females aged 11-17 years old (average 13.8 years old). The disease course was 9-16 years (average 12.1 years). There were 2 cases of congenital scol iosis and 19 cases of idiopathic scol iosis, which included 5 cases of IA, 2 of IB, 1 of IIA, 2 of IIB, 2 of IIC, 2 of IIIA, 3 of IIIB, and 2 of IVA according to Lenke classification. There were 13 cases of thoracic scol iosis and 8 of thoracolumbar scol iosis. AP view and the lateral and anterior bending view of X-ray films before and at 3 to 6 months after removing PRSS were comparatively analyzed, the coronal and the sagittal Cobb angle were measured, and the height of vertebral body on the concave side and the convex side were measured, so as to know the effect of PRSS on the growth of the vertebral endplates. Results All the implants were removed successfully with an average operation time of 2.5 hours (range 2-4 hours) and a small amount of intraoperative blood loss. Twenty-one cases were followed up for 6-72 months (average 34.4 months). The coronal Cobb angle before and after the removal of PRSS was (20.25 ± 8.25)° and (23.63 ± 8.41)°, respectively, indicating there was no significant difference (P gt; 0.05); while the sagittal Cobb angle was (39.44 ± 12.38)° and (49.94 ± 10.42)°, respectively, indicating there was a significant difference (P lt; 0.05). The height of the top vertebral body on the concave side before and after the removal of PRSS was (1.78 ± 0.40) cm and (2.08 ± 0.35) cm, respectively, and there was a significant difference (P lt; 0.01); while the height on the convex side was (2.16 ± 0.47) cm and (2.18 ± 0.35) cm, respectively, indicating no significant difference was evident (P gt; 0.05). All the 21 patients had good prognosis and no major operative compl ication occurred. Conclusion PRSS is an effective instrumentation for the management of scol iosis. After the removal of the PRSS, the correction of scol iosis can be maintained, and the spinal mobil ity can be protected and restored.