Objective To analyze and classify the characteristic of plain X-ray, CT scan, MRI and pathologic findings in ossification of the ligamentum flavum of the thoracic spine. Providing the clinic criterion to verify the extent and progression of ossification of ligaments based on medical imaging findings. Methods Twenty-four patients with thoracic myelopathy due to ossification of the ligamentum flavum underwent surgical decompression posteriorly. There were 18 males and 6 females with age ranging from 42-76 years (mean, 57.9 years). The morphology of ossification on the CT scan was divided into isotype and non-isotype. The signal intensity of ossification was compared with that of spinal cord on T2 stage in MRI, whose results were divided into four types, such as no signal, low signal, iso signal and high signal. There were two types of ossification in pathologic findings, the mature and immature ossification. 73 segments of ossified ligaments removed from surgery were evaluated and classified individually on the base of their X-ray, CT scan, MRI and pathologic findings. 27 segments of ossified ligaments were examined immunohistochemically by use of TGF-?1 antibody. The relationship between classification of X-ray, CT scan, MRI and pathology of the ossified ligaments were compared on the basis of individual segment, to determine whether there was correlation between these findings. Results The relationship between the pathologic findings of the 73 ossified fragments and the manifestation for the CT classification and MRI signal showed: 18 isotype ossification on CT scan turn out to be mature; and among the 55 non-isotype ossification, 51 were immature and 4 were mature. 22 no signal ossifications on MRI were confirmed as mature type; all the 50 low signal ossifications were immature type; and 1 iso signal ossification was immature type. 100% were matched between MRI and pathological findings, 94.5% matched between CT and pathological findings. Conclusion The extent and progression of ossification of ligaments may be verified and predicted clinically on the base of CT scan and MRI findings, which provide the clinic criterion to guide the extent and timing of decompression.

Objective　To investigate the feasibility of osteoid callus allograft as a kind of bone healing promoting materials. Methods　The osteoid callus was obtained at one week after bilateral femoral fracture of a SD rat, then was kept at -196℃ for 2 weeks. The bone defect model which bone repair was in intra-membranous osteogenesis was made at bilateral tibial shaft in 5 rats, and filled with the osteoid callus in the left defect area, the right side was filled with allogenous cancellous as control group. The specimen were processed with undecalcified technique and the sections were staining with light blue and sofranin T. Results　After 2 weeks ,there were cartilage and bone formation in the defect area of osteoid callus graft group(3/4), medullary cavity formation in bone tissue with cartilage arround it, fibrous tissues between new bone and host bone. While there were no cartilage or bone formation in the control group. Conclusion　The allograft osteoid callus is not absorbed by immunological rejection, but changed into bone tissue through endochondral osteogenesis. It is inspiring to develop osteoid callus allograft as a kind of material for bone healing.

Objective\ To observe the long term results of expansive open door laminoplasty of cervical spine for cervical spinal stenotic myelopathy.Methods\ From April 1986 to March 1988, 98 cases were operated upon with expansive open door laminoplasty of cervical spine. Sixty one cases had been followed up for an average of 11 years and 8 months. The long term results were analyzed.Results\ The best results were obtained at the third year after operation among the OPLL (32 cases),DCS (20 cases) and CSM (8 cases),with an average JOA recovery rate for an average of 72.30%in OPLL, 67.74%in DCS and 67.80%in CSM. JOA recovery rate were 66.81%in OPLL, 66.57%in DCS and 66.1%in CSM at following up for an average of 11 years and 8 months. Instability of the cervical spine and reclosed open door were not found at the follow up for an average of 11 years and 8 months.Conclusion\ The long term results of expansive open door laminoplasty of cervical spine for cervical spinal myelopathy were good and stable. Expansive open door laminoplasty of cervical spine did not affect the stability of cervical spine.\;

Objective To report a new designed technique of CT-guided percutaneous puncture for atlantoaxial lateral mass arthrodesis with bone graft and discuss its clinical usefulness and effect. Methods From March 1999 to March 2001, on the base of anatomical investigation of 56 adult cadaversatlas and axis bone specimens, 9 cases with instability of atlantoaxial were treated after reduction by traction, 4 of 9 cases underwent Halo-Vest immobilization, and the other 5 cases underwent transarticular screw fixation through C2 vertebral body for atlantoaxial instability. Of all nine cases, the articular cartilage and capsule of post lateral part of atlantoaxial joints were removed by using home made surgical instruments under CT guidance. Iliac cancellous bones obtained by puncture were implanted into the joint space. Results All cases were followed up from 2 to 17 months (average 12.7 months) and 8 cases more than 6 months. Generally, at the third to fourth month after operation, CT scan showed bony union of the grafted bone and the excessive extension and flexion X-ray films showed stable movement of the atlantoaxial joints, and then the Halo-Vest stock were removed. Conclusion This technique has obvious advantages of less trauma and hemorrhage, high union rate, easy, safe and efficiencies.

Objective To evaluate the possibility and clinical value of total spondylectomy for the treatment of spinal tumors and to investigate a reliable method of spinal reconstruction after total spondylectomy. Methods Twenty seven cases of spinal tumors which eroded both vertebral body and its attachments were treated with total spondylectomy and internal fixation as reconstruction techniques. There were benign, malignant and metastatic tumors, which involved different levels from upper cervical to lower lumbar spines. One to 3 spinal vertebrae were removed. Results Twenty three cases were followed up for 7 to 96 months (with an average of 25 months). Among them, 1 case of L 5 malignant neurofibroma and 1 case of C6,7 giant cells tumor recurred in 10 and 12 months after operation, but the patients refused further treatment. One case of C2-4 chordoma recurred 1 year after operation, after second surgery, the result was satisfactory. No recurrent signs were found in the rest of 20 cases. Among 25 cases with neurological lesions, obvious improvement were obtained in 23 after operation. Conclusion For patients with involvement of spinal vertebra eroded by tumors, total spondylectomy is an effective procedure. After total spondylectomy, spinal stability can be reconstructed by stable internal fixation system.

Objective To study the characteristics of spinal fractures in ankylosing spondylitis(AS) in order to provide data in its diagnosis and treatment. Methods 19 cases of concomitant spinal fractures following AS, admitted in our hospital between January 1994 and October 2001, were studied retrospectively. Examination of AS, including A-P and lateral X-ray films of bilateral sacroiliac joint, HLA-B27, rheumatoid test and ESR were accomplished in all patients. MRI and CT scan were taken in 12 cases. 4 cases of thoracolumbar stress fracture treated surgically were conformed to pathological examination. 2 cases received preoperative puncture biopsy under CT guidance. In the group, there were 18 males and 1 female aging from 31 to 69 years with an average of 52.6 years. Results All of 19 cases were consistent with the diagnostic standards of AS. 17 of the patients prior to spinal fracture had a history of AS with duration of mean 20.6 years ranging from 8 to 37 years. All of 19 patients had round-backed deformity of different extent. Of 19 patients, 15 cases had a traumatic history. Falls while standing and walking were the cause of injury in 9 patients. The mechanism of injury appeared to be hyperextension in 7. 11 patients had the cervical fracture, and 8 had the thoracolumbar fracture. Of the patients with cervical fracture, 10 patients were due to shearing force, 9 of whom were located at C5-C7. In patients with thoracolumbar injury, stress fractures were seen in 7 patients, all of seven fractures occurred at T10-L2. Fracture through ankylosed disc was seen in 12 and vertebral body in 7. 16 of the 19 patients sustained fractures through three columns of the spine. 5 patients were associated with dislocation. 9 patients had spinal cord injury, 8 of whom were cervical fracture. The period from the injury to the diagnosis ranged from 10 hours to 7 months (mean 29.6 days). Conclusion Spinal fractures in AS can result from a mild trauma, and are associated with a high rate of neurological injury. Most frequent mechanism of the injury is hyperextension. Shearing fracture usually occurs at the lower cervical spine and stress fracture at thoracolumbar spine. Most of the fractures involve three columns of spine; and corresponding dislocation is common. The common fracture line is through the disc space. Delay in diagnosis is not rare.

5 mm. Oblique coronal MR of secrum could show the full length of sacral never. There were some primiral espression of MR of sacral neurological dam-age -- the variation of sacral never canal, the fatty disappearance of peri-never, the route alteration of never. 14 patients were followed up from 6 to 12 months with an average of 7.1 months. According to the BMRC score system the excellent result was obtained in 9 cases, good in 1 case, no change in 1 case. Con-clusion Clinic history and neurological examination associated with X-ray, CT and MRI was the important of the diagnosis of sacral neurological damage, the new surgical approach may be a ideal approach to treat sacral neurological damage in the sacral nerve canal region.

Objective To study the clinical characteristics of atlanto-axial dislocation and instability caused by different reasons. Methods 388 cases of atlanto-axial dislocation and instability admitted between Jan 1975 and Apr 2000 were reviewed retrospectively. Results 262 cases were caused by anomaly, 71 by trauma and 55 by other reasons. 238/262 had bony deformity, including anomaly of odontoid process, atlanto-occipital assimilation, skull basilar invagination and some others. Simple anomaly of odontoid was the most commonly seen etiology. Myelopathy occurred at similar morbidity among each kind of patients. But patients who presented symptoms for longer time were more likely to have myelopathy. It is difficult to reduce chronic fractures of the odontoid process compared with the fresh fractures. 19 cases with chronic fracture suffered from severe myelopathy. Patients with chronic atlanto-axial fracture over 1 year were more likely to have secondary damage of spinal cord than those within 1 year. Conclusion Atlanto-axial dislocation and instability is more commonly caused by anomaly than trauma. Once the patients with atlanto-axial anomaly present clinical signs, they should be treated as soon as possible. Traumatic atlanto-axial instability should be treated at the early stage to avoid myelopathy.

Objective To observe the adipocytic differentiation potential of bone marrow stromal cells (BMS), and the effect of simvastatin on adipocytic differentiation of bone marrow stromal cells in vitro, and to elucidate the mechanisms of anabolic effect of simvastatin on bone formation. Methods BMS from femur and tibia of adult female BALB C mice were cultured in vitro. Changes of alkaline phosphatase (ALP) activity were determined after treatment with adipogenetic agonist (hydrocortisone 0 5 ?mol/L and indomethacin 60 ?mol/L, HI) for 6 days. Thenexpression of lipoprotein lipase (LPL) mRNA was detected by RT PCR after treatment with HI and different concentration of simvastatin for 72 h. Adipogenetic differentiation were also observed with Oil Red O staining and fluorescence activated cell sorting (FACS) after treatment with HI and different concentration of simvastatin or 100 ?g/L rhBMP 2 for 12 days. Results After BMS were treated with HI for 6 days, ALP activity was significantly decreased ( P

Objective: To observe the effect of simvastatin on osteoblastic cell differentiation of bone marrow stromal cells in vitro, and to elucidate the mechanisms of anabolic effect of simvastatin on bone formation. Methods: Bone marrow stromal cells from femur and tibia of adult female BALB C mice were cultured in vitro , after being treated with different concentrations of simvastatin for 72 h, changes of mRNA level of osteocalcin (OCN) were detected by RT PCR, change of OCN, and osteopontin (OPN) expression were examined by Western blot, and the changes of cellular alkaline phosphatase activity (ALP) were examined by histochemistry and enzymologic measurement. Results: After bone marrow stromal cells were treated with different concentration of simvastatin for 72 h, level of OCN mRNA increased, and expression of OCN and OPN also increased in a concentration dependent manner, and cellular ALP activity significantly increased in a concentration dependent manner. Conclusion: Simvastatin can stimulate osteoblastic differentiation,and improve cellular ALPase activity with high expression of osteocalcin and osteopontin in vitro. These may be parts of the mechanism of anabolic effect of simvastatin on bone formation.