Minimally Invasive Transforaminal Lumbar Interbody Fusion for Isthmic Spondylolisthesis: In Situ Versus Reduction

OBJECTIVE: The study aimed to compare the clinical outcomes of reduction versus in situ fusion with minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for isthmic spondylolisthesis. METHODS: Demographic, preoperative, and postoperative data were collected from the medical records. Radiographic fusion was assessed by use of the grading criteria of Bridwell. Preoperative and postoperative patient-reported outcomes including visual analog scale, Oswestry Disability Index, Japanese Orthopedic Association scale and improvement rate were calculated. Patient satisfaction was assessed with the criteria of Macnab (excellent, good, fair, poor). RESULTS: There were 24 patients (11 male) in the reduction group and 21 patients (10 male) in the in situ fusion group. The average follow-up was 34.75 +/- 8.06 months in reduction group and 31.05 +/- 6.52 months in the in situ fusion group (P = 0.101). There were no significant differences in hospital stay, estimated blood loss, blood transfusion, operation time, fusion grading, and complications between the 2 groups (P > 0.05). Spinal fusion rate was 91.67% (22/24) in the reduction group and 85.71% (18/21) in the in situ group (P = 0.835). There were no significant differences in Japanese Orthopedic Association scale, visual analog scale, and Oswestry Disability Index score between the 2 groups whenever preoperatively, 3-month postoperatively, or at the last follow-up (P > 0.05). According to the criteria of Macnab, the rate of excellent and good was 83.33% in reduction group and 80.95% in the in situ group (P = 0.899). CONCLUSIONS: MIS-TLIF with reduction did not induce significantly better patient-reported outcomes, spinal fusion rate, perioperative outcomes, or fewer complications in isthmic spondylolisthesis. Intentional reduction may not be a requirement in MIS-TLIF for isthmic spondylolisthesis.