Surgeon Learning Curve and Clinical Outcomes of Minimally Invasive Anterior Lumbar Interbody Fusion With Posterior Percutaneous Instrumentation

Objectives:This study reports the learning phase of the minimally invasive anterior lumbar interbody fusion (mini-ALIF) approach with a vascular and orthopaedic spine surgeon team.Methods:Adult patients who underwent primary mini-ALIF at the lowest two segments of the lumbar spine (i.e., L4/5, L5/S1) between January 2010 and December 2018 were analyzed.Results:One hundred twenty-seven patients were included. There was no notable change in total surgical time over the study period. Estimated blood loss markedly decreased until stabilizing at case 30 and slowly declined thereafter. The mean estimated blood loss was 184 mL for L5/S1, 232 mL for L4/L5, and 458 mL for two-level mini-ALIF. There were 20 vascular issues requiring primary repair or packing. Vascular issues declined over time, with a rate of 32% in the first 25 cases and 0% in the last 25. The postoperative complication rate was highest in the first 25 cases (7 of 21 total complications). The odds ratio of vascular injury with body mass index (BMI) > 35 was 4.09 (1.4 to 11.7 confidence interval, P <= 0.008). Total surgical time and postoperative complications increased with increasing BMI.Conclusion:Performance of the mini-ALIF approach is associated with a learning curve of 25 to 30 cases before complications begin to decline. BMI > 35 is associated with increased surgical time and complications.