Effect of rod curvature on lumbar lordosis in one level spinal fusion surgery

Abstract

inadequate lumbar lordosis during lumbar fusion surgery may result in mechanical low back pain, sagittal imbalance and adjacent segment degeneration. Studies on single level fusion are limited and controversially. Due to the importance of rod curvature in spinal lordosis alignment, in this study we decided to investigate the effect of rod curvature in maintaining the normal curvature of the lumbar spine in patients of Imam Reza Hospital in Tabriz as a referral center in the northwest of the country. Method: This study was a randomized controlled trial and was performed on 60 patients with degenerative spondylolisthesis grade 1 single space L4 / L5 referred to Imam Reza Hospital who were candidates for posterolateral fusion with pedicular screw and met the inclusion criteria from 2016 to 2018. Patients were randomly divided into two groups. In the first group, the rod was placed in place without giving curvature and in the second group, the rod was placed under the appropriate curvature in the desired space. Surgery Out come was calculated based on VAS( visual analog scale) back and leg in immediate after surgery and final follow-up one year after surgery. At this stage, all patients underwent full-length standing radiography to calculate lumbar lordosis angle, segmental lordosis and focal lordosis. And were compared in two groups. Results : The mean age of 60 patients participating in the study was 7.02 ± 57.55 years, with a minimum age of 40 years and a maximum age of 70 years. BMI of patients was 31.57 ± 6.51 with a minimum of 20.12 and a maximum of 42.16. The difference between BMI in the study groups was not significant. The rate of back pain visual analogue scale (VAS) of patients before fusion surgery was 7.53 ± 1.59, which during one-year follow-up, the rate of VAS significantly decreased ( P value = 0.000 and reached 2.30 ± 1.62). The rate of leg pain visual analogue scale (VAS) of patients before fusion surgery was 7.48 ± 1.68, which during one-year follow-up, the rate of VAS significantly decreased( P value = 0.000 and reached 2.98 ± 1.85). The rate of lumbar lordosis of patients before surgery was 36.72 ± 12.46 which after surgery and in one-year follow-up reached 38.58 ± 8.31 which was not statistically significant (P value = 0.087). L4 / L5 focal lordosis before surgery was 11.73 ± 6.13 which in one-year follow-up reached 12.98 ± 6.28 which was statistically significant (P value = 0.041) but there was no significant difference between the two groups. The rate of segmental lordosis in patients before surgery was 4.17 3. 3.17 which reached 4.18 ± 4.69 after surgery and in one-year follow-up, which was statistically significant (P value = 0.039), which was no significant difference between the two groups one-year follow-up length.