Transsacral interbody fixation versus transforaminal lumbar interbody fusion at the lumbosacral junction for long fusions in primary adult scoliosis.

Achieving fusion at the lumbosacral junction poses many technical challenges. No data exist in the literature comparing radiographic or clinical outcomes between the different surgical techniques of transsacral fixation (TSF) with rods and transforaminal lumbar interbody fusion (TLIF) in conjunction with iliac fixation. The purpose of this study was to compare the clinical outcomes and radiographic fusions of TSF to TLIF in patients with adult spinal deformity undergoing long fusions across the lumbosacral junction. Patients with primary adult spinal deformity who underwent long fusions from the thoracic spine across the lumbosacral junction with different approaches of interbody fusion at the L5-S1 level were reviewed. Patients were subdivided by approach (TSF vs TLIF). Fusion status at L5-S1 was evaluated by multiple radiographs and/or CT scans. Scoliotic curve changes were also evaluated preoperatively and at final follow-up. Clinical outcomes were assessed by Scoliosis Research Society Outcome Instrument 22 and Oswestry Disability Index scores. A total of 36 patients were included in the analysis. There were 18 patients in the TSF group and 18 patients in the TLIF group. A mean of 14.00 levels were fused in the TSF group and 10.94 in the TLIF group (p = 0.01). Both groups demonstrated significant postoperative radiographic improvement in coronal parameters. The fusion rates for TSF and TLIF groups were 100% and 88.9%, respectively (p < 0.05). Eight patients in the TSF group had pelvic fixation with unilateral iliac screws, compared to 15 patients in the TLIF group (p = 0.015). No statistical differences in patients' reported outcomes were seen between groups. Despite similar clinical and radiographic outcomes between both groups, TSF required fewer iliac screws to augment stability of the lumbosacral junction while achieving a higher rate of fusion. This study suggests that TSF may decrease potential instrument-related complications requiring revision while decreasing operating room time and implant-related costs.