XLIF vs. MAS TLIF for the Treatment of Degenerative Spondylolisthesis: Interim Results from an Ongoing Prospective Multi-Center Comparative Study

Presented at SMISS Annual Forum 2013
By Antoine Tohmeh MD
With Jonathan Sembrano MD, SOLAS Degenerative Study Group , Robert Isaacs MD,

Disclosures: Antoine Tohmeh MD A; NuVasive. B; NuVasive. C; NuVasive. D; NuVasive. F; NuVasive. Jonathan Sembrano MD A; NuVasive, Inc - PI for an RCT comparing MAS-TLIF vs XLIF, SI Bone Inc., SOLAS Degenerative Study Group A; NuVasive, Inc. B; NuVasive, Inc. C; NuVasive, Inc. D; NuVasive, Inc. F; NuVasive, Inc., Robert Isaacs MD A; NuVasive. B; NuVasive, Providence Medical Technology. C; Association for Collaborative Spine Research. D; SafeRay Spine, LLC, SafeWire, LLC, VilaSpine LTD, Vertera Spine, Providence Medical Technol,

Introduction: This prospective, multicenter, IRB-approved study aims to compare indirect decompression via XLIF and direct posterior decompression via TLIF for the treatment of low-grade spondylolisthesis with a specific interest in clinical and radiographic results. This abstract serves as an interim report of the 6 month outcomes.

Methods: Adult patients with Grade I-II degenerative spondylolisthesis at one or two lumbar levels were treated with either MAS TLIF or XLIF. Motor/sensory evaluations were conducted by the treating physician. Patient reported outcomes and radiographic measurements were also collected pre- and post-op.

Results:  At the time of analysis 48 patients (25 XLIF, 23 TLIF) out of 55 enrolled had completed 6-month follow-up, and early post-op neural deficit data was available for 55 patients (29 XLIF, 26 TLIF). Pre-op neural deficits resolved after surgery in 100% of XLIF and 73% of TLIF patients. Mean surgery times favored XLIF (171 min vs 186 min). 79% of XLIF and 27% of TLIF patients lost less than 100mL blood (p < 0.01). There were 3 dural tears in the TLIF group and none in the XLIF group. Mild transient post-op hip flexion weakness presented in 34% of XLIF patients, which all resolved by 6 months. 1/29 XLIF patients had new distal motor deficits noted postoperatively, which resolved by 6 months. New post-op sensory deficits were noted in 2/29 XLIF and 2/26 TLIF patients, which all resolved. Post-op VAS and ODI scores were similar between groups, and both showed significant improvement over baseline.
XLIF resulted in less segmental motion and less early post-op subsidence. Postoperative lumbar lordosis, approach-side foraminal dimensions, and reduction of spondylolisthesis were similar between treatment groups. At 3 months contralateral foraminal height was significantly greater than approach-side foraminal height within the TLIF group only.

Conclusion: In this early interim analysis comparing XLIF to TLIF for the treatment of low-grade degenerative spondylolisthesis, only subtle differences were identified. Patient-reported pain, function, and satisfaction are comparable. Continued study follow-up is required to make stronger comparisons between procedures.