INTRODUCTION: The use of transforaminal lumbar interbody fusion (TLIF) has expanded greatly in recent years and failed procedures inevitably occur. Treatment of failed TLIF is challenging from a posterior approach, particularly when cage removal is needed. Cage removal via an anterior approach allows for wide access to the cage(s) for removal and placement of a single, large, lordotic implant while avoiding neurologic structures. Though anterior approach carries risks of vessel injury. Limited information is available in the literature for this revision strategy. The purpose of this study is to assess the technique and safety of anterior lumbar interbody fusion (ALIF) for treating failed TLIF.
METHODS: The records of ALIF cases were reviewed and those involving failed TLIF were identified. This produced a consecutive series of 50 patients (47 had TLIF performed at other facilities). Medical records were reviewed to collect data including general patient descriptive information, TLIF cage type, reasons for TLIF cage removal, details of the cage removal and ALIF, and if revision of posterior instrumentation was also performed.
RESULTS: Among the 50 patients, the number of levels revised per patient were: 40 1-level, 8 2-level, and 2 3-level. Pseudoarthrosis was related to TLIF failure in all cases. Other factors present included infection (n=2), cage malpositioning and/or migration (n=6), and subsidence (n=1). The average duration of time after TLIF to ALIF revision was 43.5 months. The mean blood loss during the ALIF procedures was 159.6 ml. In 42 cases, the revision was performed as planned with the TLIF cage(s) being removed and replaced with a single ALIF cage. In the remaining 8 cases, the operative plan needed to be modified to address challenges encountered with cage removal. In 4 cases the TLIF cages could not be removed easily and were intentionally broken to allow piece meal removal. In 3 cases, the cages could not be removed and were burred down to create space to insert an interbody fusion cage. In one patient, TLIF cage removal was performed as planned at L5-S1; however, the cage removal was aborted at L4-5. This was found to be a very collapsed space with the TLIF cage entrapped in the posterior margin and there was concern of neural trauma during attempted removal. Allograft and demineralized bone matrix were placed anterior to the cage to promote fusion. The only vascular injury in the series was a tear in the common iliac vein which was noted after TLIF cage removal. This was packed during ALIF cage placement and repaired with suture without further event. The estimated blood loss in this case was 600 ml. Revision or replacement of posterior instrumentation was performed in almost all cases.
DISCUSSION: ALIF for revision of failed TLIF can be successfully accomplished in most patients. Surgeons performing such cases should be well acquainted with the ALIF approach and working with an experienced access surgeon. The surgeon should also have a plan for salvage maneuvers for situations where the TLIF cage(s) cannot be completely removed in one piece as planned.