Minimally invasive extreme lateral lumbar interbody fusion (XLIF) to manage adjacent level disease – A case series and literature review

The incidence of adjacent level disease, in patients who have undergone a previous open posterior pedicle screw and rod instrumented fusion, is reported to be as high as 30% at 5-year follow-up. Due to the traditional revision open posterior surgery used to manage these patients being fraught with complications, several studies have compared this to newer MIS interbody fusion techniques. While the PLIF and TLIF inter-body fusion procedures have shown promising results, nerve root tethering by scar tissue limits the amount of retraction that can be safely performed, and as such may limit access to the disc space of the adjacent level. The ALIF is an anterior alternative, however several studies note it to be characterized by a high complication rate. As such the XLIF has been evaluated as an alternative to the ALIF, PLIF, and TLIF procedures and, despite several advantages, several papers note it to have its own specific set of complications despite the mandatory utilization of intra-operative electromyographic neurophysiological monitoring. As such an attending spinal surgeon, when managing a patient with adjacent level disease, must have a through understanding of the pros and cons of each possible surgical technique that could be used to manage the adjacent level. We present a series of three patients, all of which had previously undergone an open posterior instrumented lumbar fusion, and now presented to our unit with adjacent level disease. Two patients were successfully managed with a minimally invasive XLIF procedure augmented by open posterior decompression and extension of the instrumented fusion, and one patient was successfully managed by a minimally invasive stand-alone XLIF procedure without additional open posterior surgery. Our case series serves to highlight the specific and valuable role of the MIS XLIF procedure, specifically in the context of patients presenting with adjacent level disease.