Lumbar lordosis and sacral slope have no differences in two types of postoperative lumbar disc re-herniation: a cross-sectional observational study

Abstract

Background: To identify the differences of lumbar lordosis (LL) and sacral slope (SS) angles between two types of postoperative lumbar disc re-herniation, including the recurrence of same level and adjacent segment herniation (ASH). Methods: We searched the medical records of lumbar disc herniation (LDH) patients with re-herniation with complete imaging data (n=58) from January 1, 2013 to December 30, 2020 in our hospital. After matching for age and sex, 58 patients with LDH without re-herniation from the same period operated by the same treatment group in our hospital were served as a control group. Re-herniation patients were divided into two groups, same-level recurrent lumbar disc herniation group (rLDHG) and adjacent segment herniation group with or without recurrence (ASHG). The preoperative, postoperative and one month after operation LL and SS were measured on standing radiographs and compared with the control group by using t-test，ANOVA, and rank-sum test．Next, we calculated the odds ratios (ORs) by unconditional logistic regression, progressively adjusted for other confounding factors. Results: Compared with the control group, the postoperative LL and SS were significantly lower in LDH patients with re-herniation. However, there were no differences in LL and SS between ASHG and rLDHG at any stage. After progressive adjustment for confounding factors, no matter what stage is, LL and SS remained unassociated with the two types of re-herniation. Conclusions: The postoperative LL and SS are independent risk factors for lumbar disc re-herniation. Low LL and SS angles at any stage do not appear to determine the type of re-herniation, as this is decided by many other factors, such as age, genes and so on.