Characteristics of endplate changes in patients with lumbar disc herniation treated by discectomy and their effects on clinical symptoms during one-year postoperative follow-up.

Purpose: The impact of endplate changes, such as Modic changes (MCs), on symptoms following discectomy remains uncertain. This study aimed to investigate the postoperative progression of MCs and bony endplate defects after discectomy for lumbar disc herniation (LDH) and to elucidate its association with clinical outcomes.

Methods: A total of 247 patients who underwent microscopic discectomy were included. The natural progression of MCs and bony endplate defects at the operated level were assessed using magnetic resonance imaging. Clinical outcomes were evaluated using a visual analog scale (VAS) and the Roland-Morris Disability Questionnaire. The study examined the progression of endplate changes and their impact on clinical outcomes, with a focus on the type of postoperative MC.

Results: The natural progression of postoperative MCs was varied, with MCs coexisting with bony endplate defects (p < 0.001). Persistent or converted type 1-related MCs were more likely to exacerbate pre-existing signal changes at one year and were associated with higher VAS scores for low back pain (LBP) compared to type 2 MCs (p < 0.001). Patients with type 1-related MCs (β: 0.429, p < 0.001) and preoperative LBP (β: 0.215, p = 0.025) were closely associated with residual LBP at one year or more.

Conclusion: In patients with baseline signal changes in subchondral bone marrow, the presence of type 1 MCs was more likely to promote the increase of MCs than type 2. Furthermore, the presence of type 1 MCs may predict residual postoperative LBP, suggesting that bone marrow signal changes are more strongly associated with clinical symptoms than morphological changes in bony endplates in patients with LDH.