Object: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is used to treat a wide variety of lumbar degenerative disorders. Although there are some reports showing efficacy of unilateral instrumentation during MIS-TLIF, a controlled randomized prospective study has not been done.
Methods: Forty-one patients were randomly assigned to receive either bilateral or unilateral instrumentation following 1-level unilateral MIS-TLIF. Four patients were lost to follow-up in the unilateral group and 1 patient was lost to follow-up in the bilateral group. Preoperative and postoperative scores on a visual analog scale (VAS) for back pain and leg pain (VAS-BP and VAS-LP, respectively), Oswestry Disability Index (ODI), and 36-Item Short Form Healthy Survey version 2 (SF-36v2) were collected. Additionally, preoperative and postoperative segmental Cobb angles and radiographic evidence of fusion were analyzed.
Results: There was no statistically significant difference in baseline demographic characteristics between the 2 groups. The VAS-BP, VAS-LP, ODI, and SF-36v2 physical component scores improved significantly after surgery in both groups (p < 0.05); there was no statistically significant between-groups difference in the degree of improvement. Blood loss was significantly higher in the bilateral instrumentation group and hospital stay was longer in the unilateral instrumentation group. There was no statistically significant between-groups difference with respect to change in segmental lordosis or fusion rate. The average duration of follow-up was 12.4 months for the bilateral instrumentation group and 11.4 months for the unilateral instrumentation group.
Conclusions: Clinical and radiographic outcomes of unilateral and bilateral instrumentation for unilateral MISTLIF are similar 1 year after surgery.