Recurrent Lumbar Disc Herniation After Tubular Microdiscectomy: Analysis of Learning Curve Progression.

OBJECTIVE: Tubular microdiscectomy has become a staple technique among spine surgeons. Yet the associated learning curve, especially its later stages, has not been extensively studied. With studies reporting a higher rate of recurrent herniation using tubular microdiscectomy, surgeons' level of experience becomes of primary importance for the interpretation of such findings. We aimed to analyze possible improvements in the later stages of the learning curve and to identify factors independently associated with recurrent herniation.

METHODS: A retrospective study was conducted using prospectively collected data from a consecutive cohort of all 1241 patients operated for single-level lumbar disc herniation with tubular microdiscectomy by a single surgeon who already had extensive experience with this technique. We collected demographic and perioperative data and consequently tracked all complications, recurrent herniations, and other reoperations. In addition, 495 patients (40%) provided complete outcome scores on a numeric rating scale for back and leg pain and the Oswestry Disability Index at baseline, 6 weeks, and 12 months postoperatively.

RESULTS: A decrease in surgical time (P < 0.001) and recurrent herniations was observed (P = 0.012) over time. Increased leg pain at 6 weeks was independently associated with recurrent herniation (P = 0.01). Fifty-six patients (4.5%) experienced ipsilateral recurrent herniation.

CONCLUSIONS: Relevant improvements in clinical results were seen even after the surgeon had already accumulated extensive experience. Any future studies should unambiguously report the level of experience of the participating surgeons, possibly including the number of cases previously treated using a particular technique.