411 - XLIF vs. MAS TLIF for the Treatment of Degenerative Spondylolisthesis:...

#411 XLIF vs. MAS TLIF for the Treatment of Degenerative Spondylolisthesis: Perioperative Clinical Outcomes from a Prospective Multi-Center Randomized Study

Lumbar Therapies and Outcomes

Poster Presented by: J. Sembrano


R. Isaacs (1)
J. Sembrano (2)
F. Zahrawi (3)

(1) Duke University, Durham, NC, USA
(2) University of Minnesota, Minneapolis, MN, USA
(3) Celebration Minimally Invasive Spine Institute, Celebration, FL, USA


Introduction: The aim of this prospective, multicenter, institutional review-board approved study is to compare indirect anterior decompression via XLIF and direct posterior decompression via TLIF for the treatment of low-grade spondylolisthesis with a specific interest in clinical and radiographic outcomes. As this study is currently enrolling, this abstract serves as an interim report of the early (3 month) outcomes.

Methods: Adult patients with Grade I or 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 include VAS, ODI, and satisfaction. Radiographic measures including average disc height, spondylolisthesis, disc angle, foraminal height, and lumbar lordosis were collected using pre- and 3-month radiographs.

Results: At the time of analysis 34 patients (18 XLIF, 16 TLIF) had completed 3-month follow-up. Motor/sensory evaluation by the treating physician revealed hip flexion weakness at the peri-op visit in 38% of XLIF patients and 0% in TLIF patients. Additional distal (i.e., lower extremity) weakness was detected in 1 XLIF patient. There was 1 (7%) incident of distal motor weakness in the TLIF group that presented at 6 weeks and resolved by 3 months. All but one incidence of XLIF hip flexion weakness had resolved by 3 months with the incidence of distal weakness persisting. There was an 18% incidence of new sensory deficit in XLIF after surgery with 12% persistent at 12 weeks. In TLIF there was a 13% incidence of new postoperative sensory deficit which increased to 20% at 12 weeks. There were no differences between VAS-Back, VAS-Leg, or ODI scores at any time point.

XLIF resulted in greater increase in segmental disc angle and lumbar lordosis. Increase in disc height, foraminal height and reduction of spondylolisthesis were similar between treatment groups.

Conclusion: XLIF appears to result in similar perioperative patient-reported symptoms and measured lower-extremity deficits, and a higher incidence of perioperative hip flexion weakness that resolves by 3 months when compared to TLIF. Patient-reported pain, function, and satisfaction are comparable between groups. XLIF may result in greater foraminal dimensions compared to TLIF. Due to the small initial sample size of this ongoing study, statistical differences are not yet apparent. Continued study enrollment and longer follow-up are required to make stronger comparisons between procedures for the treatment of low-grade degenerative spondylolisthesis.