No abstract

The precise location of the dural sac (DS) end is necessary for preventing neural injury during spinal surgery or procedures. There has been no report on problems with spine surgery in patients with early DS termination. A 28-year-old woman presented with low back and leg pain involving the left S1 nerve root. Magnetic resonance imaging (MRI) revealed early DS termination at the lower one-third of the L5 vertebra and lumbar disc herniation at the L5/S1. Microscopic discectomy was performed instead of endoscopic discectomy to avoid unpredictable risks. Due to early DS termination, multiple nerve roots were identified, which look like nerve root congenital anomalies (Neidre and Macnab type II anomalies), and multiple separated nerve roots appeared to exit through a single foramen. After wide exposure by hemilaminectomy, which facilitated adequate visualization and mobilization of the involved nerve roots, the ruptured disc was identified and removed with gentle retraction, avoiding risk of excessive nerve root traction. Unlike other nerve root anomalies, early DS termination could be detected easily with preoperative MRI. Although this condition appears similar to other nerve root anomalies in the surgical field, it is possible to avoid inadvertent neural injury by closely investigating preoperative MRI. If early DS termination is suspected, it is necessary to consider a safer surgical approach.

The purpose of this study was to observe the natural course of remained untreated spondylolysis adjacent to previous fusion segments in patients with multi-level lysis and its clinical outcome. Methods: Nineteen patients who underwent selective fusion of multi-level spondylolysis (MLS) at a single institute were enrolled. As a matched cohort for comparison, 19 patients who had single-level spondylolysis (SLS) and undergone singlelevel fusion with similar demographics and preoperative radiologic measurements as the MLS group were included. We evaluated the preoperative, postoperative, and last followup angular displacement and sagittal translation on dynamogram radiographs, and axial and radial pain using the visual analogue scale in both groups. We then compared the increment in radiological instability and clinical outcome between the MLS and SLS groups. Results: There were no significant differences in patient demographics and preoperative radiological measurements, including disc degeneration, facet degeneration, lumbar lordosis, pelvic incidence, and sacral table angle between both groups. Both groups showed an increase in the average angular displacement and slippage during the final follow-up as compared to preoperative findings, but no significant difference was noticed between them. Both the MLS and SLS groups showed improvement in lower back pain and leg pain from before surgery, but with no statistical significance. Conclusion: Selective fusion in patients with multiple spondylolysis can be an alternative surgical option without increasing the risk of adjacent segment degeneration under strict narrow indications. However, a thorough preoperative evaluation is needed to prevent early surgical failure.