Introduction: While long-term studies have evaluated adjacent segment degeneration in posterior lumbar spine arthrodesis, no such studies have evaluated the axial interbody fusion technique. To our knowledge, this is the largest reported number of cases that underwent the Axial Lumbar Interbody Fusion (AxiaLIF) in the United States. An analysis was performed to determine the incidence of adjacent segment disease in patients who have undergone index one or two level interbody fusion via the presacral approach using the AxiaLIF System with concurrent percutaneous pedicle screw fixation.

Methods: We retrospectively reviewed the medical records of 153 patients who underwent index axial lumbar interbody and had both presurgical and 2-year radiographic and clinical follow-up. The average duration of follow-up was 5.0 years. Adjacent segment disease was defined as both radiographic and clinically significant disease at a level adjacent to a previous fusion requiring surgical intervention. 1,2

Results: A single-level L5-S1 fusion was performed in 5 patients and a 2-level (L4-S1) fusion was used in 148 patients. Of the patients undergoing 2-level (L4-S1) fusion, 35 (23.6%) underwent subsequent laminectomy or laminectomy with extension of fusion. The most common reasons for reoperation were radiculopathy (57.1%), spinal stenosis (22.9%), instability (22.9%) or progressive loss of sagittal balance (8.6%). None of the patients with a single level (L5-S1) fusion underwent reoperation. Kaplan-Meier analysis predicted a disease-free survival rate of 81.1% (95% confidence interval, 74.8% to 87.4%) at two years and of 75.6% (95% confidence interval, 68.59% to 82.7%) at five years for 2-level (L4-S1) fusion.

Conclusions: For 2-level AxiaLIF, the rate of symptomatic degeneration warranting either decompression or arthrodesis was found to be 18.9% at two years and 24.4% at five years. The greatest indications for reoperation were radiculopathy, spinal stenosis, instability or loss of sagittal balance. There appears to be a higher incidence of adjacent level disease following multi-level vs single level fusions.

Patient Care: This research provides outcomes data on minimally invasive methods of fusion in the lumbar spine and may help clinicians decide how to best approach patients with spondylolisthesis in the future.

Learning Objectives: Describe the axial lumbar interbody fusion using the pre sacral approach. Describe the incidence of reoperation following a 2 level AxiaLIF and the most common indications for re operation.

References: 1. Bydon M, Macki M, Kerezoudis P, Sciubba DM, Wolinsky JP, Witham TF, et al. The incidence of adjacent segment disease after lumbar discectomy: A study of 751 patients. J Clin Neurosci. 2017;35:42-46 2. Lee JC, Lee SH, Peters C, Riew KD. Adjacent segment pathology requiring reoperation after anterior cervical arthrodesis: The influence of smoking, sex, and number of operated levels. Spine (Phila Pa 1976). 2015;40:E571-577