Pseudarthrosis following lumbar and lumbosacral fusion using the antepsoas technique

Study Design. Retrospective case–control study. Objective. The aim of this study was to evaluate the prevalence of pseudarthrosis following antepsoas (ATP) lumbar and lumbosacral fusions. Summary of Background Data. Pseudarthrosis is a feared complication following spinal fusions and may affect their clinical outcomes. To date there are no sufficient data on the fusion rate following ATP lumbar and lumbosacral arthrodesis. Methods. This is a retrospective review of 220 patients who underwent lumbar minimally invasive antepsoas (MIS-ATP) fusions between January 2008 and February 2019 who have at least 1-year postoperative computed tomography (CT) follow-up scans. Fusion was graded using CT scans imaging and adopting a 1–4 grading scale (1, definitely fused; 2, likely fused; 3, likely not fused; 4, definitely not fused/nonunion). Grades 3 or 4 indicate pseudarthrosis. Results. A total of 220 patients (average age: 66years, 82 males (37.2%), and 127 (57.7%) smokers) were included. Eight patients (3.6%) developed pseudarthrosis. A total of 693 discs were addressed using the ATP approach. Of those, 681 (98.3%) were considered fused (641 levels [92.5%] were ‘‘definitely fused’’ and 40 levels [5.8%] were ‘‘Likely fused’’) and 12 discs (1.7%) developed pseudarthrosis (seven levels [1.0%] were ‘‘likely not fused’’ and five levels (0.7%) were ‘‘definitely not fused’’). The highest rate of pseudarthrosis was found at L5-S1 (4.8%) compared to the L1-L5 discs (0–2%). Of 127 smokers, six developed pseudarthrosis (odds ratio ¼ 2.3, P¼0.3). The fusion rates were 95.3% and 97.8% for smokers and nonsmokers, respectively. Of the eight patients who developed pseudarthrosis, only four (50%) were symptomatic, of whom two (25%) required revision surgery. Both of these patients were smokers. The overall revision rate due to pseudarthrosis was 0.9% (two of 220 patients). Conclusion. The MIS-ATP technique results in a high fusion rate (96.4% of patients; 98.3% of levels). Pseudarthrosis was noted mostly at the L5-S1 discs and in smokers.