Multifidus fat infiltration negatively influences the postoperative outcomes in lumbar disc herniation following transforaminal approach percutaneous endoscopic lumbar discectomy.

Objective: This study aims to investigate the influence of multifidus muscle fat infiltration on clinical outcomes in lumbar disc herniation (LDH) undergoing percutaneous endoscopic lumbar discectomy (PELD).

Methods: A retrospective analysis was conducted on 224 patients who underwent lateral PELD, with complete one-year follow-up data. Patients were divided into two groups based on preoperative MRI evaluation of L4 multifidus muscle fat infiltration: a mild group (< 25%) and a severe group (≥ 25%). Baseline characteristics and postoperative outcomes were recorded and compared.

Results: At the final follow-up, significant improvements in VAS scores for back and leg pain, ODI scores, and EQ-5D scores were observed in both groups. There were no statistically significant differences in preoperative VAS scores for back and leg pain, ODI scores, and EQ-5D scores between the two groups. However, significant differences were found in VAS scores for back pain, ODI scores, and EQ-5D scores at 3, 6, and 12 months postoperatively (P < 0.05), while no significant difference was noted in VAS scores for leg pain during follow-up. The total recurrence rate was 6.7% (15 out of 224 cases), with 12 cases in the severe group and 3 cases in the mild group, showing a statistically significant difference (P < 0.05).

Conclusions: The effectiveness of postoperative PELD in patients with LDH is impacted by severe multifidus muscle fat infiltration. Multifidus muscle fat infiltration represents a risk factor for recurrent LDH after PELD.