Non-union rate with stand-alone lateral lumbar interbody fusion

Abstract

Retrospective radiographic analysis.To determine the fusion rate of stand-alone lateral lumbar interbody fusion (LLIF). Biomechanical studies have indicated that LLIF may be more stable than anterior or transforaminal lumbar interbody fusion. Early clinical reports of stand-alone LLIF have shown success in obtaining fusion and indirectly decompressing nerve roots. A consecutive case series of stand-alone LLIF was analyzed with chart and radiographic review. Non-union was determined by symptomatology consistent with non-union and absence of bridging bone on the CT scan. Thirty-nine levels of stand alone LLIF were performed in 23 patients. Eleven patients received 1-level surgery, 7 patients received 2-level surgery, 3 patients received 3-level surgery, and 1 patient received 4-level surgery. Excluding 1 infected case, we analyzed 37 levels of stand alone LLIF in 22 patients. Non-union incidence was 7 levels in 6 patients. Non-union rate was 7/37 (19%) per level and 6/22 (27%) per patient. While our study population was relatively low, a non-union rate of 19% to 27% is concerning for modern spine surgery. Currently in our practice, we occasionally still perform stand-alone LLIF utilizing 22 mm wide grafts in low-demand levels in non-smoking and non-osteoporotic patients. However, in a majority of patients, we provide supplemental fixation: bilateral pedicle screws in most patients and unilateral pedicle screws or spinous process plates in some patients.

FIGURE 1

Pre-operative CT scan showing L2 to L3 degeneration and stenosis adjacent to previous L3 to S1 fusion.

FIGURE 2

After 3 month pain-free interval, neurogenic claudication symptoms returned. Six-month postoperative CT scan shows subsidence of graft and ossification of annular bulge causing stenosis.