LAUSR

OBJECTIVE To evaluate clinical and radiological outcomes between bilateral decompression using over-the- top technique (Group 1) and unilateral decompression (Group 2) in patients with claudication who underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). METHODS We enrolled patients with claudication who underwent MIS-TLIF from January 2017 to June 2019. Visual analog scale (VAS), Oswestry Disability Index (ODI) scores, walking distance and perioperative outcomes were compared between groups. Preoperative and 3-month postoperative magnetic resonance imaging scan assessed changes in canal cross-sectional area, foraminal height, and lateral recess area. RESULTS Sixty-five consecutive patients with at least one year of follow-up were enrolled. VAS and ODI scores were not significantly different between groups (VAS and ODI, respectively, at 1-month follow-up: P=0.62, 0.88; 3-month follow-up: P=0.96, 0.53; 6-month follow-up: P=0.10, 0.85; and 12-month follow-up: P=0.10, 0.66). Operative time and blood loss between groups was not found statistically significant (P=0.43 and p=0.55). There was also no difference in the length of hospital stay (P=0.24). Canal dimensions increased in each group without significant differences between groups (cross-sectional area: P=0.92; foraminal height [approach and contralateral side, respectively]: P=0.62, 0.66; and lateral recess area [approach and contralateral side, respectively]: P=0.68, 0.50). CONCLUSIONS Unilateral approach with ipsilateral side direct decompression and contralateral indirect decompression in MIS-TLIF is sufficient for early clinical improvement in patients with claudication.