Influence of Alendronate and Endplate Degeneration to Single Level Posterior Lumbar Spinal Interbody Fusion

OBJECTIVE: Using alendronate after spinal fusion is a controversial issue due to the inhibition of osteoclast mediated bone resorption. In addition, there are an increasing number of reports that the endplate degeneration influences the lumbar spinal fusion. The object of this retrospective controlled study was to evaluate how the endplate degeneration and the bisphosphonate medication influence the spinal fusion through radiographic evaluation. METHODS: In this study, 44 patients who underwent single-level posterior lumbar interbody fusion (PLIF) using cage were examined from April 2007 to March 2009. All patients had been diagnosed as osteoporosis and would be recommended for alendronate medication. Endplate degeneration is categorized by the Modic changes. The solid fusion is defined if there was bridging bone between the vertebral bodies, either within or external to the cage on the plain X-ray and if there is less than 5degrees of angular difference in dynamic X-ray. RESULTS: In alendronate group, fusion was achieved in 66.7% compared to 73.9% in control group (no medication). Alendronate did not influence the fusion rate of PLIF. However, there was the statistical difference of fusion rate between the endplate degeneration group and the group without endplate degeneration. A total of 52.4% of fusion rate was seen in the endplate degeneration group compared to 91.3% in the group without endplate degeneration. The endplate degeneration suppresses the fusion process of PLIF. CONCLUSION: Alendronate does not influence the fusion process in osteoporotic patients. The endplate degeneration decreases the fusion rate.

Recurrence Rate after Herniotomy only versus Discectomy in Lumbar Disc Herniation

OBJECTIVE: Lumbar disc herniation (LDH) recurrence necessitating reoperation can pose problems following spinal surgery, with an overall reported incidence of approximately (3-13%). The purpose of this study is to identify the rate of recurrent disc herniation, to discuss the radiologic indications for herniotomy and to analyze clinical outcomes compared with conventional discectomy. METHODS: This study is a retrospective case control study. The authors retrospectively reviewed 114 patients who underwent herniotomy & conventional discectomy by a single surgeon for single-level LDH between June 2009 and May 2012. Herniotomy group was 57 patients and conventional discectomy group was 57 patients that were selected from 631 patients using stratified randomization. Evaluation for LDH recurrence included detailed medical chart and radiologic review and telephone interview. Postoperative VAS and the Korean version of ODI were examined one week after surgery. Clinical outcome was investigated according to Odom's criteria from three months to three years. RESULTS: Of the 114 patients for whom the authors were able to definitively assess symptomatic recurrence status, four patients (7%) experienced LDH recurrence following single-level herniotomy and three patients (5.2%) conventional discectomy. There were no differences in the VAS and Korean version of ODI between herniotomy group and conventional discectomy group. The herniotomy group had better results than the conventional discectomy group in clinical outcome from three months to three years, but the difference was not significant. CONCLUSION: There were no significant differences in clinical outcome between herniotomy and conventional discectomy. Recurrence rates following herniotomy for LDH compare favorably with those in patients who have undergone conventional discectomy, lending further support for its effectiveness in treating herniotomy.