Percutaneous axial lumbar interbody fusion (axiaLIF) of the L5-S1 segment: Initial clinical and radiographic experience

Introduction: Anterior access to the L5-S1 disc space for interbody fusion can be technically challenging, frequently requiring the use of an approach surgeon for adequate exposure. We reviewed our experience with a novel minimally invasive technique for L5-S1 interbody fusion that exploits the presacral space and its relative dearth of critical structures. Methods: 35 patients (20 F: 15 M, mean age 54 years) were included in this analysis. Average follow-up was 17.5 months. Back pain was secondary to lumbar degenerative disc disease (DDD), degenerative lumbar scoliosis, or lytic spondylolisthesis. All patients had radiographic evidence of L5-S1 degeneration and underwent percutaneous paracoccygeal axial fluoroscopically-guided interbody fusion (axiaLIF) with cage, local bone autograft, and rhBMP. Results: Mean operative time for the L5-S1 axiaLIF procedure was 42 minutes. Twenty-one patients underwent axiaLIF followed by percutaneous L5-S1 pedicle screw-rod fixation. Two patients underwent axiaLIF followed by percutaneous L4-L5 extreme lateral interbody fusion (XLIF) and posterior instrumentation. Ten patients had a stand-alone procedure. Unfavorable anatomy precluded access to the L5-S1 disc space during open lumbar interbody fusion in 2 patients who subsequently underwent axiaLIF at this level as part of a large construct. Thirty-two patients (91%) had radiographic evidence of stable L5-S1 interbody cage placement and fusion at the last follow-up. Conclusions: The percutaneous paracoccygeal approach to the L5-S1 interspace provides a minimally invasive corridor through which discectomy and interbody fusion can safely be performed. It can be used alone or in combination with minimally invasive or traditional open fusion procedures. It may provide an alternative route of access to the L5-S1 interspace in those patients who may have unfavorable anatomy for or contraindications to the traditional open anterior approach to this level.