ObjectiveTo evaluate the medium-term effectiveness of Waveflex system in the treatment of multiple lumbar degenerative diseases. MethodsBetween May 2010 and July 2012, 26 patients with multiple lumbar degenerative diseases underwent posterior decompression, transforaminal lumbar interbody fusion (TLIF), and internal fixation with Waveflex system. There were 15 males and 11 females, aged 23-65 years (mean, 34.2 years). The disease duration was 9 months to 8 years (median, 3 years and 3 months). The lesion located at L3-S1. The visual analogue scale (VAS), Oswestry disability index (ODI), and the short-form 36 health survey scale (SF-36) were used to evaluate the status of clinical recovery, meanwhile the Stauffer-Coventry evaluation standard was used to access the satisfaction at last followup; the disc space height (DSH), intervertebral angle (IVA), and range of motion (ROM) were measured on X-ray film or three-dimensional CT, and the adjacent segment degeneration was classified by Pfirrmann score based on MRI findings. ResultsAll patients obtained primary incision healing without nerve injury, cerebrospinal fluid leakage, or internal fixation failure. All patients were followed up 31-50 months (mean, 40.6 months). The VAS, ODI, and SF-36 scores were significantly improved at 6 months after operation and last follow-up when compared with preoperative ones (P<0.05), but no significant difference was found between at 6 months and last follow-up (P>0.05). According to the StaufferCoventry evaluation standard, the results were excellent in 21 cases, good in 2 cases, moderate in 2 cases, and poor in 1 case, with an excellent and good rate of 88.5% at last follow-up. X-ray films showed that there was no complication of screws pulling-out or fixed rod rupture and displacement. At 7 days, 6 months, and last follow-up, the DSH of adjacent segment was significantly increased (P<0.05), and the ROM of adjacent segment was significantly decreased (P<0.05) when compared with preoperative ones; there was no significant difference in IVA between at pre-and post-operation (P>0.05). According to Brantigan grade for fusion, 19 cases were rated as grade E, 6 cases as grade D, and 1 case as grade C, and the fusion rate was 96%. There was no significant difference in Pfirrmann score between at pre-operation and last follow–up (Z=0.000, P=1.000). ConclusionThe Waveflex system combined with TLIF is effective and safe to treat multiple lumbar degenerative diseases during medium-term follow-up.
ObjectiveTo evaluate the effect of poly-amino acid/nano-hydroxyapatite/calcium sulfate (PHC) Cage in lumbar interbody fusion of the goat. MethodsEighteen mature female goats (weighing 29-33 kg) were divided into 3 groups randomly: PHC Cage group (group A), titanium Cage group (group B), and ilium group (group C). A left extraperitoneal approach was used to establish the animal model of discectomy and interbody fusion with Cage or ilium. The general situation was observed for 24 weeks after operation. X-ray films were taken to measure disc space height (DSH) before operation and at 4, 12, and 24 weeks after operation. CT three dimensional reconstuction was performed at 24 weeks after operation to evaluate the interbody fusion according to modified Brantigan grading. The specimens of L3, 4 were harvested for mechanical test, histological, and scanning electron microscope (SEM) observation at 24 weeks after operation. ResultsAll goats survived to the end of experiment. DSH at 4 weeks after operation increased when compared with preoperative one in each group, and then decreased;DSH was significantly lower at 12 and 24 weeks after operation than preoperative one in group C (P<0.05). There was no significant difference in DSH among 3 groups at preoperation and 4 weeks after operation (P>0.05);at 12 and 24 weeks after operation, DSH of groups A and B was significantly higher than that of group C (P<0.05), but no significant difference was found between groups A and B (P>0.05). CT three dimensional reconstuction showed that bony fusion was obtained in all goats of groups A and C, and in 3 goats of group B;according to modified Brantigan grading, the scores of groups A and C were significantlly higher than that of group B (P<0.05), but no significant difference between groups A and C (P>0.05). The biomechanical test showed that there was no significant difference in range of motion between group A and group B (P>0.05), which were significantly lower than that of group C (P<0.05). Microscopy and SEM observations showed that the interface between the Cage and vertebral body in group A was compact without obvious gap, and most conjunctive region was filled with osseous tissue;the interface was filled with soft tissue, and the connection was slack with obvious gap in some region in group B;the interface connection was compact, most region was filled with osseous tissue in group C. ConclusionThe interbody fusion with PHC Cage is effective in goat lumbar interbody fusion model. The interface connection is compact between the Cage and the host bone followed by micro-degradation of PHC Cage, but the long-term degradation need further observation.