Alif With Auto-Locking Cage Without Supplementation - Tomographic Analysis of Interbody Bone Fusion

Abstract

Objective: The objective of this work is to study the fusion rate and complications of the mini-ALIF with an auto-locking device at the L5-S1 level. Methods: Retrospective and radiological study. The inclusion criteria were mini-ALIF in L5-S1 with auto-locking cage, DDD and/or low grade spondylolisthesis. The exclusion criteria were posterior/anterior supplementation; lack of 12-month follow-up images, and previous surgery at L5-S1 level. The primary endpoint was fusion assessed in CT images and/or lateral lumbar flexion/extension radiographs. The secondary endpoint was the revision surgery due to device movement/migration or pseudoarthrosis. Lumbar TCs and radiographs were analyzed during 12 months of follow-up. Fusion was defined according to Bridwell/Lenke classification. Results: Sixty-one cases were included in this study. Complete or ongoing fusion was found in 57 cases (93%). Forty-two of the 61 levels (65%) were completely fused after 12 months. Fifteen levels (28%) had evident bone growth, two levels (3%) showed lysis lines around the implant, and two levels (3%) presented lysis lines and depression. Reoperation for pedicular screw supplementation was necessary in two cases (3%), one with vertebral sliding progression (12 months), and one with symptomatic micro-movement (six months). No implant has undergone migration or expulsion of the disc space. Conclusions: Mini-ALIF in L5-S1 level using an auto-blocking interbody implant construction in cases of low segmental instability results in good interbody fusion index and low failure rate, even without the need for further supplementation, but should not be applied indiscriminately. Evidence Level: IV. Type of study: Case series.