Modic changes in patients with lumbar disc herniation followed more than 1 year after lumbar discectomy: a systematic review and meta-analysis

Background: Modic changes (MCs) are identified as an independent risk factor for low back pain. Different subtypes of MCs vary in their impact on postoperative pain relief. However, consensus on the transformation of postoperative MC fractions in patients with distinct MC subtypes is lacking. Methods: This comprehensive systematic review and meta-analysis searched English-language articles in PubMed, Cochrane Library, Web of Science, and Embase databases until January 2024. Studies included focused on patients transitioning between various microcrack subtypes post-discectomy. The primary outcome measure was the transformation between different postoperative microcrack fractions. Results: Eight studies with 689 participants were analyzed. Overall, there is moderate to high-quality evidence indicating differences in the incidence of MC conversion across MC subtypes. The overall incidence of MC conversion was 27.7%, with rates of 37.0%, 20.5%, and 19.1% for MC0, MC1, and MC2 subtypes, respectively. Thus, postoperative MC type transformation, particularly from preoperative MC0 to MC1 (17.7%) or MC2 (13.1%), was more common, with MC1 transformation being predominant. Patients with preoperative comorbid MC1 types (19.0%) exhibited more postoperative transitions than those with MC2 types (12.4%). Conclusion: This study underscores the significance of analyzing post-discectomy MCs in patients with lumbar disc herniation, revealing a higher incidence of MCs post-lumbar discectomy, particularly from preoperative absence of MC to MC1 or MC2. Preoperative MC0 types were more likely to undergo postoperative MC transformation than combined MC1 or MC2 types. These findings are crucial for enhancing surgical outcomes and postoperative care.