Intra-operative identification of conjoined lumbosacral nerve roots: a report of three cases.

We report 3 cases of conjoined nerve root anomalies identified during micro-endoscopic discectomy (MED). Between 2009 and 2010, 61 men and 20 women aged 18 to 84 (mean, 42) years underwent MED for symptomatic lumbar disc herniation of L3-4 (n=1), L4-5 (n=44), and L5-S1 (n=36). Magnetic resonance imaging (MRI), myelogram, and postmyelo computed tomography did not identify the anomalies. All 3 patients were male and had type 2A S1 conjoined nerve roots, with a herniated disc at L5-S1. None of them had any preoperative pseudolocalising neurological signs, but all demonstrated stiffer positive straight leg raise sign and deterioration of the Achilles tendon reflex. Postoperatively, all 3 patients achieved excellent clinical outcomes.