Stand-alone lateral lumbar interbody fusion for the treatment of symptomatic adjacent segment degeneration following previous lumbar fusion

Background context: Revision posterior decompression and fusion surgery for patients with symptomatic adjacent segment degeneration (ASD) is associated with significant morbidity and is technically challenging. The use of a stand-alone lateral lumbar interbody fusion (LLIF) in patients with symptomatic ASD may prevent many of the complications associated with revision posterior surgery.

Purpose: The objective of this study was to assess the clinical and radiographic outcomes of patients who underwent stand-alone LLIF for symptomatic ASD.

Study design: This is a retrospective case series.

Patient sample: We retrospectively reviewed patients with a prior posterior instrumented fusion who underwent a subsequent stand-alone LLIF for ASD by a single surgeon. All patients had at least 18 months of follow-up. Patients were diagnosed with symptomatic ASD if they had a previous lumbar fusion with the subsequent development of back pain, neurogenic claudication, or lower extremity radiculopathy in the setting of imaging, which demonstrated stenosis, spondylolisthesis, kyphosis, or scoliosis at the adjacent level.

Outcome measures: Patient-reported outcomes were obtained at preoperative and final follow-up visits using the Oswestry Disability Index [ODI], visual analog scale (VAS)-back, and VAS-leg. Radiographic parameters were measured, including segmental and overall lordoses, pelvic incidence-lumbar lordosis mismatch, coronal alignment, and intervertebral disc height.

Methods: Clinical and radiographic outcomes were compared between preoperative and final follow-up using paired t tests.

Results: Twenty-five patients met inclusion criteria. The mean age was 62.0±11.3 years. The average follow-up was 34.8±22.4 months. Fifteen (60%) underwent stand-alone LLIF surgery for radicular leg pain, 7 (28%) for symptoms of claudication, and 25 (100.0%) for severe back pain. Oswestry Disability Index scores significantly improved from preoperative values (46.6±16.4) to final follow-up (30.4±16.8, p=.002). Visual analog scale-back (preop 8.4±1.0, postop 3.2±1.9; p<.001), and VAS-leg (preop 3.6±3.4, postop 1.9±2.6; p<.001) scores significantly improved following surgery. Segmental and regional lordoses, as well as intervertebral disc height, significantly improved (p<.001) and remained stable (p=.004) by the surgery. Pelvic incidence-lumbar lordosis mismatch significantly improved at the first postoperative visit (p=.029) and was largely maintained at the most recent follow-up (p=.45). Six patients suffered from new-onset thigh weakness following LLIF surgery, but all showed complete resolution within 6 weeks. Three patients required subsequent additional surgeries, all of which were revised to include posterior instrumentation.

Conclusions: Stand-alone LLIF is a safe and effective approach with low morbidity and acceptable complication rates for patients with symptomatic ASD following a previous lumbar fusion.