Pear-Shaped Disc as a Risk Factor for Postoperative Sclerotic Modic Changes After Transforaminal Lumbar Interbody Fusion.

Objective: Pear-shaped disc could increase the risk of intraoperative end-plate injury, which may lead to postoperative sclerotic Modic Changes (MCs). However, there are no studies on the relationship between pear-shaped disc and postoperative sclerotic MCs. Therefore, this study investigates the risk factors for postoperative sclerotic MCs following transforaminal lumbar interbody fusion (TLIF). Specifically, the study focuses on the impact of pear-shaped disc on the occurrence of postoperative sclerotic MCs and evaluates its influence on clinical outcomes.

Methods: A total of 411 patients undergoing TLIF between January 2018 and January 2022 were included. Among them, 50 developed postoperative sclerotic MCs, while 361 did not. The two groups were matched based on various parameters. Clinical and radiographic evaluations, including visual analogue scale (VAS), Oswestry disability index (ODI), lumbar X-ray, CT, and MRI, were performed. Statistical analysis included independent sample t test, Pearson's chi-square test, and binary logistic regression analysis.

Results: After pairing, a total of 100 patients were included, including 50 patients in postoperative sclerotic MCs group and 50 patients in non-MCs group. There were 27 pear-shaped discs in the postoperative sclerotic MCs group, significantly higher than 7 in the non-MCs group (p < 0.001). Besides, BMI, endplate injury, and cage subsidence in the postoperative sclerotic MCs group were significantly higher than those in the non-MCs group, but the fusion rate was significantly lower than that in the non-MCs group. The postoperative and follow-up SL and surgical corrections of SL in postoperative sclerotic MCs group were significantly higher than those in non-MCs group. The independent risk factors identified for postoperative sclerotic MCs include pear-shaped disc and higher BMI.

Conclusion: Pear-shaped disc and higher body mass index (BMI) as independent risk factors for postoperative sclerotic MCs. Patients with sclerotic MCs exhibited a lower fusion rate, increased cage subsidence, and poorer symptom improvement compared to those without MCs.