Radiographic Evaluation of a Modular Anterior Lumbar Interbody Fusion (ALIF) Cage: Subsidence and Segmental Lordosis

Anterior lumbar interbody fusion (ALIF) is an established intervention for degenerative pathology and sagittal plane corrections. Despite advances in implant technology, challenges such as vertebral endplate damage, implant subsidence, and loss of segmental lordosis remain. A modular ALIF cage, designed with an endplate-first insertion technique, aims to protect endplates, reduce insertional trauma, and enable precise restoration of disc height and lordosis. The purpose of this study was to evaluate early radiographic outcomes after implantation of a modular ALIF device, specifically examining the incidence of implant subsidence and changes in segmental lordosis.

A multicenter retrospective analysis of 23 patients was conducted to evaluate the Axis-ALIF Modular Cage (Axis Spine Technologies Ltd, Leeds, UK) implanted in a total of 27 levels. ALIF was undertaken primarily for the treatment of symptomatic disc degeneration unresponsive to nonoperative care. Radiographs were obtained preoperatively, at early postoperative follow-up, and at final follow-up (range: 3 to 24 months; mean: 6.6 months). These images were evaluated by an independent core lab using an automated image analysis platform to assess cage subsidence and segmental lordosis.

No radiographic evidence of subsidence was observed in the 24 levels with complete paired imaging data, with the mean change in disc height being 0.002 mm (range: -0.69 to 0.78 mm). Segmental lordosis increased by approximately 8° immediately postoperatively and remained stable at follow-up (mean change: +0.02°).

In this small retrospective cohort, the modular ALIF implant demonstrated consistent early radiographic findings, with no observed subsidence and maintained segmental lordosis. These findings support further prospective evaluation in larger controlled studies.