ObjectiveTo explore the long-term effectiveness of expandable Cage in treatment of degenerative lumbar disease. MethodsBetween January 2005 and January 2008, 72 patients with degenerative lumbar disease were treated by expandable Cage and followed up for 5 years. Of 72 cases, 41 were male and 31 were female with an average age of 40.5 years (mean, 35-65 years), including 35 cases of lumbar spinal stenosis, 20 cases of degenerative lumbar instability, and 17 cases of serious lumbar intervertebral disc protrusion combined with lumbar instability. The disease duration was 6-28 months (mean, 9 months). The affected lumbar segments were L3, 4 in 6 patients, L4, 5 in 37 patients, and L5, S1 in 29 patients. The Oswestry disability index (ODI) was used to evaluate the effectiveness before and after operation and to calculate the improvement rate. During the follow-up, the anteroposterior, lateral, and dynamic X-ray films were taken to evaluate the operated segment fusion rate. The intervertebral lordosis angle was measured, and adjacent segment degeneration was observed. ResultsThe operation time was 35-90 minutes (mean, 65 minutes); the intraoperative blood loss was 200-450 mL (mean, 280 mL), and all the patients received intraoperative autologous blood transfusion; the postoperative bedridden time was 3-7 days (mean, 4.5 days); the hospitalization days were 10-18 days (mean, 12 days). No complications of nerve root injury, cauda equina injury, or cerebrospinal fluid leakage occurred during operation. All patients achieved primary healing of the incisions. All 72 patients were followed up for 5 years. At 3 months, 1 year, and 5 years after operation, the ODI were 8.2±2.6, 6.9±1.9, and 6.4±1.3 respectively, showing significant differences when compared with preoperative value (41.5±3.5) (P<0.05); the improvement rates were 87.3%±1.2%, 90.1%±0.8%, and 91.6%±1.3% respectively, showing no significant difference (F=0.492, P=0.375); the intervertebral lordosis angles were (5.1±1.2), (5.0±0.5), and (5.4±0.8)°respectively, showing no significant difference (F=0.570, P=0.453). At 5 years after operation, the intervertebral fusion rate was 100%, with no adjacent segment degeneration. ConclusionUsing expandable Cage to treat degenerative lumbar disease can get stabilization without pedicle screw fixation, the good effectiveness is shown after long-term follow-up.
ObjectiveTo evaluate the ectopic osteogenesis of recombinant human bone morphogenetic protein 2 (rhBMP-2) loaded chitosan (CS)/dextran sulfate (DS) by micro-CT. MethodsrhBMP-2/CS/DS microspheres were prepared by the ionic crosslinking and its shape was observed under the scanning electron microscope. The release of rhBMP-2 was determined from resultant microspheres by ELISA assay. Forty-eight Sprague Dawley male rats were randomly divided into 4 groups (n=12), quadriceps muscle bag model was made, gelatin sponge (group A), CS/DS microspheres (group B), rhBMP-2 (group C), and CS/DS/rhBMP-2 microspheres (group D) were implanted into the bags respectively. The tissue samples with heterotopic ossification were harvested for micro-CT scanning at 4, 8, 12, and 16 weeks. The tissue mineral density (TMD), bone volume fraction (BVF), trabecular thickness (Tb.Th), trabecular number (Tb.N), bone mineral density (BMD), and tissue mineral content (TMC) were measured. ResultsThe prepared rhBMP-2/CS/DS microspheres with smooth surfaces were spherical and evenly disperses without obvious agglomeration. At 2 hours, microsphere started a sudden release period in vitro; the release reached a peak at 2 days; and the release cycle lasted about 20 days. The rats survived to the end of the experiment. At each time point after operation, no radiation developed and no osteogenesis was observed by three dimensional reconstruction in groups A and B. However, radioactive strength and reconstructed bone tissue gradually increased in groups C and D, and group D had more radioautography and more bone tissues than group C. At each time point, TMD, BVF, Tb.Th, Tb.N, BMD, and TMC of groups A and B were zero. Ectopic bone formed with time, the other parameters showed an increasing trend except Tb.N in groups C and D, showing significant difference when compared with groups A and B at each time point (P < 0.05). There was no significant difference between groups C and D at 4 weeks (P>0.05); the parameters of group D were significantly higher than those of group C at 8-16 weeks (P < 0.05). ConclusionrhBMP-2/CS/DS microspheres have stronger ability of ectopic bone formation than single rhBMP-2.