Comparison of Adjacent Segment Degeneration After Minimally Invasive or Open Transforaminal Lumbar Interbody Fusion: A Minimum 5-Year Follow-up.

Abstract

This was a retrospective case series. The purpose of this study was to compare radiologic and clinical outcomes in patients with L4-L5 lumbar spinal stenosis (LSS) who had undergone either minimally invasive (MIS-) or open (O-) transforaminal lumbar interbody fusion (TLIF), especially with regard to the development of adjacent segment degeneration (ASDeg). ASDeg is defined as the degenerative changes at adjacent segments of a fused segment, with no obvious clinical symptoms. A total of 121 LSS patients with a minimum 5-year follow-up were included. Patients were divided into 2 groups according to the surgery performed (MIS-TLIF: 57 patients, O-TLIF: 64 patients). Preoperative and final follow-up radiologic parameters were determined. The incidence of ASDeg was evaluated and compared between the 2 groups. Visual Analog Scale score, Japanese Orthopaedic Association score, and Oswestry Disability Index were used to assess clinical outcomes. Before surgery, no significant difference was found between MIS-TLIF and O-TLIF groups regarding demographic, radiologic, and clinical data. After a 5-year follow-up, the incidence of ASDeg in LSS patients was 47.1% (57/121). ASDeg was mostly located at the cranial segment of the fused level in each group. The most common type of ASDeg in both groups was intervertebral space collapse. There was a lower chance of ASDeg in MIS-TLIF group than that in O-TLIF group (33.3% vs. 59.4%, P <0.01). Postoperatively, both groups had significant improvement in clinical outcomes, and there were no statistically significant intergroup differences assessed by Visual Analog Scale, Japanese Orthopaedic Association, and Oswestry Disability Index scores. The clinical effect of MIS-TLIF and O-TLIF were similar, but the incidence of ASDeg was significantly lower after MIS-TLIF at 5-year follow-up.