Comparing the Effect of Alendronate and Vitamin D Administration on Lumbosacral Fusion and Severity of Low Back Pain in Patients After Posterior Lumbar Fusion Surgery: A Randomized Clinical Trial

Background and purpose: Bone fusion is a dynamic process and availability of calcium and balance of vitamin D can be effective in post spinal cord fusion. There are contradictory results on this issue, so, we decided to compare the effect of administration of vitamin D and alendronate on lumbosacral vertebral fusion in patients undergoing posterior spinal fusion surgery. Materials and methods: A single-blind clinical trial was carried out in 75 patients. Patients were divided into three groups (n=25 per group) using block randomization: Alendronate group who received 70 mg oral alendronate every two weeks, Vitamin D group to receive vitamin D 50,000 units per month for six months, and control group who received routine treatment after the surgery. After six months, the patients underwent CT scan of the lumbar region for clinical assessment of lumbar fusion. Pain intensity was assessed using Visual Analogue Scale (VAS), one and six months after the surgery. Data analysis was performed in SPSS V16. Results: Before surgery, pain intensity was higher in vitamin D group (6.36 ± 1.3) than the controls and alendronate group (P <0.0001). The last VAS in this group reached 2.12 ± 0.97 indicating decrease in pain intensity. Overall, there was a significant decrease in pain intensity in all three groups (P<0.0001). Non-fusion was found to be more frequent in control group (16%) compared to the vitamin D (12%) and alendronate (8%) groups (P=0.900). Conclusion: In current study, vitamin D and alendronate supplementation slightly improved lumbosacral fusion. Therefore, further studies are needed to investigate the effectiveness of combined treatment with alendronate and vitamin D on pain intensity and lumbosacral fusion in these patients.   (Clinical Trials Registry Number: IRCT20180826040869N2)