Is increased segmental motion early after lumbar discectomy related to poor clinical outcome 5 years later?

The purpose of the study was to compare segmental motion in the early postoperative phase after lumbar discectomy to the outcome 5 years postoperatively. The study population had radiologically verified symptomatic L4-L5 or L5-S1 lumbar disc herniation and was referred with an indication for lumbar discectomy. Radiostereometry was performed in the supine and standing positions. The L4-L5 and L5-S1 segments were analysed separately. L4-L5 segments adjacent to the operated L5-S1 segment constituted a reference segment for the operated L4-L5 and vice versa. Twenty-one patients were available for the follow-up at 5 years. Outcome was classified as functionally good or poor. Repeated or planned repeat surgery at the same level during follow-up was considered as poor outcome. The L4-L5 segments in the poor group showed different direction of sagittal rotation (anterior versus posterior) of L4 on L5 compared with the good group (p<0.01). On the L5-S1 segment, patients with poor outcome displayed an increased anterior translation of about 1 mm (p<0.01) compared with the reference segments. Our study suggests that increased inducible vertebral displacement in the early postoperative phase after discectomy is associated with a poor clinical outcome.