LAUSR

STUDY DESIGN Retrospective cohort study OBJECTIVES.: To report the feasibility, nuances, technical tips as well as outcomes of managing single-level grade D (extreme stenosis) and to compare the outcomes with non-extreme stenosis using the tubular retractor system. SUMMARY OF BACKGROUND DATA Minimally invasive decompression in extreme stenosis is a challenge due to technical difficulty, feasibility of adequate decompression and a steep learning curve. METHODS Consecutive patients from January 2007-January 2017 presenting with neurogenic claudication secondary to single level spinal stenosis operated using tubular retractors were included in the study. The patients were divided into 2 groups; extreme-stenosis and non-extreme stenosis. The outcomes of surgery were evaluated and compared using VAS (Visual analogue score) for leg and back pain, ODI (Oswestry disability index) and MacNab's criteria. RESULTS A total of 325 patients (out of 446 patients after excluding the multi-level cases) fulfilled the inclusion criteria. 140 patients were cases of extreme stenosis and 185 were non-extreme stenosis. The mean VAS for back and leg pain for extreme stenosis improved from 3.23 ± 1.30 to 2.15 ± 0.91 and 7.33 ± 0.78 to 1.66 ± 1.03 respectively as compared to non-extreme stenosis where the mean VAS for back and leg pain improved from 3.01 ± 1.15 to 1.86 ± 1.10 and 6.57 ± 1.00 to 1.54 ± 1.12 respectively. The mean ODI changed from 66.47 ± 7.53 to 19.95 ± 2.90 in extreme stenosis as compared to non-extreme stenosis where mean ODI changed from 59.05 ± 5.08 to 19.88 ± 2.67. As per MacNab's criteria 102 (of 120 patients) and 139 (of 157 patients) reported excellent and good outcomes in extreme and non-extreme stenosis respectively. CONCLUSIONS Tubular decompression is feasible in patients with extreme-stenosis with no difference in the outcomes as well as complication rates when compared with a cohort of non-extreme stenosis. LEVEL OF EVIDENCE 3.