Lumbar Disc Herniation and Preoperative Modic Changes: A Prospective Analysis of the Clinical Outcomes After Microdiscectomy

Abstract

Study design: Prospective comparative cohort study. Objectives: The study aims to elucidate the relationship between Modic endplate changes and clinical outcomes after a lumbar microdiscectomy. Methods: Consecutive patients undergoing microdiscectomy for lumbar disc herniation (LDH) were prospectively studied. Pre-operative clinical and radiological parameters were recorded. The pain was assessed by Numeric pain rating scale (NPRS), and functional assessment by Oswestry Disability Index (ODI). Minimal clinically important difference (MCID) in outcome was calculated for both the groups. Complications related to surgery were studied. Follow-up was done at 6 weeks, 3 months, 6 months and 1 year. Mac Nab criteria were used to assess patient satisfaction at 1 year. Results: Out of 309 patients, 86 had Modic changes, and 223 had no Modic changes. Both groups had similar back pain (p-value: 0.07) and functional scores (p-value: 0.85) pre-operatively. Postoperatively patients with Modic changes had poorer back pain and ODI scores in the third month, sixth month and 1 year (p-value: 0.001). However, MCID between the groups were not significant (p-value: 0.18 for back pain and 0.58 for ODI scores). Mac Nab criteria at 1 year were worse in Modic patients (p-value: 0.001). No difference was noted among Modic types in the pre-operative and postoperative pain and functional outcomes. Four patients in Modic group (4.7%) and one patient in the non-Modic group (0.5%) developed postoperative discitis (p-value: 0.009). Conclusions: Preoperative Modic changes in lumbar disc herniation is associated with less favorable back pain, functional scores and patient satisfaction in patients undergoing microdiscectomy.