Clinical and Radiological Fate of the Lumbosacral Junction Following ALIF vs. Axial Lumbar Interbody Fusion at the Bottom of a Long Construct in cMIS treatment of Adult Spinal Deformity

Presented at SMISS Annual Forum 2016
By Neel Anand MD
With Eli M. Baron MD, Babak Khandehroo MD, Sheila Kahwaty PA-C, Ryan Cohen , Jason Cohen ,

Disclosures: Neel Anand MD None Eli Baron MD , Babak Khandehroo MD None, Sheila Kahwaty PA-C None, Ryan Cohen None, Jason Cohen None,

Introduction

Surgeons use numerous arthrodesis strategies for fusion of the lumbosacral junction including ALIF and AxiaLIF. Nonetheless, the optimal L5-S1 fusion strategy remains inconclusive. The purpose of this study is to compare the fate of the lumbosacral junction in ALIF vs. AxiaLIF patients in terms of clinical and radiographic outcomes.

Aims/Objectives

ALIF is the preferred method of lumbosacral fusion in terms of radiographic and clinical outcomes.

Methods

This is a retrospective study of 83 patients (mean age 67.3) who underwent circumferential minimally invasive surgical (CMIS) correction of ASD (Cobb angle>20 degrees or SVA>50mm or PI-LL mismatch>10) that underwent AxiaLIF or ALIF with at least 2-year follow-up. Patients were separated into two groups: AxiaLIF (56 pts) and ALIF (27 pts). The groups were compared in terms of 

segmental lordosis (SL), sagittal vertical alignment (SVA), lumbar lordosis (LL), pelvic incidence-lumbar lordosis (PI-LL) mismatch, as well as, pseudoarthrosis, major complication, and re-operation rates.

Results

The ALIF group achieved significantly greater postop SL (ALIF group: 17.67o, AxiaLIF group: 9.53o), higher delta-SVA (ALIF group: 36.16mm, AxiaLIF group: 5.33mm), higher postop LL (ALIF group: 46.6o, AxiaLIF group: 39.9o), higher delta-LL (ALIF group: 6.35o, AxiaLIF group: .11o), and lower postop PI-LL mismatch (ALIF group: 10o, AxiaLIF group: 16.4o). There was a trend towards lower postop SVA and higher delta-PI-LL mismatch in the ALIF group. The pseudoarthrosis, major complication, and reoperation rates trended higher in the AxiaLIF group. Overall, 6 cases of pseudoarthrosis were reported in the entire cohort, 5 of which occurred as a consequence of Axial LIF.

Conclusions

ALIF patients showed more favorable SL and sagittal correction, as well as, a lower trend in rates of pseudoarthrosis, major complications, and reoperations compared to AxiaLIF patients. We propose that ALIF is the preferred strategy for L5-S1 arthrodesis due to these superior radiographic and clinical outcomes.