BACKGROUND: Several studies have demonstrated that bone marrow mcscnchymal stem cells (MSCs) can differentiate into osteoblasts after induction of bone morphogenetic protein (BMP).OBJECTIVE: This study was designed to compare the osteogenetic effects between MSCs, bBMP, and fibrin gel alone and their composite.DESIGN: A controlled observation experiment.SETTING: Second People's Hospital of Guangdong Province and Second Hospital Affiliated to Sun Yat-sen University.MATERIALS: This study was performed at the Second Hospital Affiliated to Sun Yat-sen University between January 2004 and June 2006. Healthy New Zealand rabbits were provided by the Laboratory Animal Center, Sun Yat-sen University.METHODS: Bone marrow was taken from the lilac bone. By density gradient centrifugation, autologous MSCs were in vitro cultured and amplified. A composite was made of fibrin gel and bovine bone morphogenetic protein (bBMP). After adding MSCs, another composite was made. Twelve rabbits underwent lumbar L3/4, LA/5, and LS/6 discectomy and interbody fusion via an anterior retroperitoneal approach. Three fusion sites in each animal were randomly assigned into three of four treatments: composite of MSCs and hBMP and fibrin gel (group A), composite of MSCs and fibrin gel (group B), composite of bBMP and fibrin gel (group C) and fibrin gel alone (group D). The interbodies were observed radiologically and histologically 3 months after surgery.MAIN OUTCOME MEASURES: Bone formation in the spinal interveRebral space of rabbits.RESULTS: Twelve weeks after surgery, bone formation was appasenfly greater in the Group A than in the other groups.Histological findings revealed continuous bone formation. The groups B and C showed equivalent radiological and histological changes. Bone formation was intermittent. Group D had fibrous union, but no bone formation. No residual fibrin gel was found in all groups, but a small amount of residual nucleus gelatinosus with a little cartilaginous tissue was visible in the intervertebral disc.X-ray examination results did not reveal vertebral posterior hyperplasia or spinal stenosis. There was significant difference in range of lumbar motion between the group B and the groups C and D (P ＜ 0.05). No pronounced difference in vertebral posterior height loss existed among the groups.CONCLUSION: The composite of MSCs, fibrin gel and bBMP can promote bone regeneration and achieve osseous spinal fusion.

Objective To provide the morphological evidence for sensory pathway by the repair of dorsal root (DR) in which received transected and anastomosed with central processes (DR) and peripheral processes (spinal nerve) respectively. Methods 74 SD rats were divided into three groups randomly. Group A: the distal ending of L6 DR was sutured to the proximal ending of the L4 DR in right side. Group B: the postganglionic spinal nerve of L4 was cut at a point 2 mm to intervertebral foramen and its proximal stump was reconnected to the distal ending of L6 DR in right side. Group C: under the same operative manipulation on group B, but no anastomosis was performed to serve as the sham operation group. The left side was kept intact and served as a normal control in all groups. The repairing results of DR axonal regeneration were evaluated at 3 months after operation by retrograde tracing, the density of positive Calcitonin gene-related peptide (CGRP) axon in dorsal root entry zone (DREZ), survival rate of neurons in DR ganglia and posterior horn, light and transmission electron microscope. Results HRP retrograde tracing demonstrated axonal axoplasmic transport of regenerative nerve recovered well in group B. Regenerative fibers were found. There was no difference between group A or B and normal control with regard to the number of myelinated axons and the thickness of myelin. Regenerating axon stop at the DREZ in group A and the density of positive CGRP were lower than those in group B and normal control. Survival rate of neurons in L6 DR ganglia had no difference among all groups. However, in posterior horn, a significant increase in death was seen in group A and sham group. Conclusion The ability of axonal regeneration was effective and with no disservice to neurons in posterior horn following anastomosis of postganglionic spinal nerve and dorsal root, by which axoplasmic transport across the DREZ into the spinal cord.

Objective To discuss the value of the posterior long segments pedicle screws fixation in surgical treatment of thoracolumbar fracture-dislocation,and summarize the experience.Method s We reviewed the clinical information of 27 cases of thoracolumbar fracture-dislocation since July 2007 to March 2010; all the cases were treated with the posterior long segments pedicle screws fixation.In these cases,20were male,7 were female.And the age ranged from 18 to 58 years old (average age was 35 years).The posterior approach was used,and the pedicle screws were inserted into the 2 vertebrae above and below the fractured vertebrae.Posterior decompression and bone grafts for fusion were also accomplished during the operation.Results Follow-up ranged from 7 to 25 months,averaging 14 months.Completely restoration of the dislocation was got in 25 cases and the spine sequence resumed to nearly normal.One case with lateral dislocation failed to complete correction; another 1 case operated 20 days after surgery failed to complete correction of forward dislocation.At the last follow-up,the mean Cobb angle loss was 3 degrees,the height of the vertebral had obvious loss compared with that of post-operation.The loosen of screw nut was found during the follow-up,but no dislocation and secondary deformity were observed after fixation.There was no death,no infection.Conclusions The technique of posterior long segments pedicle screw fixation is of great value in the clinical applications,since it has the following advantages:the operation is simple,trauma is small,the fixation is firm,good restoration of fracture and dislocations can be easily got,and most importantly,it can effectively prevent long-term vertebral height loss and the backward protruding deformity.

Objective To explore the clinical efficacy and application value of hemivertebra resection for treating congenital ky‐phoscoliosis .Methods 30 cases of congenital kyphoscoliosis and hemivertebral deformity in our hospital from January 2011 to Jan‐uary 2013 were selected as the research subjects .Among them ,12 cases of simple vertebral and non‐structural bending were per‐formed the posterior hemivertebral resection and short segment pedicle screw fixation ;3 cases of complicating lordosis and hemiver‐tebral protruding to the ventral side were performed the anterior hemivertebral resection and bone graft fusion fixation ;15 cases of complicating structural compensatory curve were performed the posterior transpedicle hemivertebral resection and compensatory bend long segment fixation and fusion .The clinical effects of surgical treatment for all patients were performed the comparative a‐nalysis .Results The mean postoperative kyphosis Cobb angle and the average final follow‐up Cobb angle were (8 .6 ± 3 .14) °and (11 .2 ± 7 .23) °respectively .The ultimate orthopedic rate of kyphosis was 58 .6% ;the average postoperative Cobb angle and and the average final follow‐up Cobb angle of scoliosis were (12 .8 ± 5 .47)°and (16 .2 ± 6 .24)°respectively ,the final orthopedic rate of scoliosis was 66 .5% .The mean Cobb angle of kyphosis and scoliosis after operation was significantly less than that before opera‐tion ,the difference was statistically significant(P< 0 .05) .Kyphosis and scoliosis were significantly improved .No significant post‐operative complications occurred .The effects were satisfied by the patients .Conclusion The hemivertebral resection has significant effect for treating congenital kyphoscoliosis with high kyphoscoliosis orthopedic rate and is worthy of further clinical study .