Learning curve and clinical outcomes of percutaneous endoscopic transforaminal decompression for lumbar spinal stenosis

Purpose To define and analyze the learning curve of percutaneous endoscopic transforaminal decompression (PETD) for lumbar spinal stenosis (LSS). Methods From July 2015 to September 2016, 78 patients underwent PETD; one of whom was converted to open surgery, two were lost, and 75 were included in this study. Clinical results were assessed by using the Oswestry Disability Index (ODI) and visual analog scale (VAS). The learning curve was assessed by a logarithmic curve-fitting regression analysis. Of these 75 patients, 35 were defined as the “early” group, and 40 were defined as the “late” group for comparison. Results The mean follow-up was 25.37 ± 4.71 months. The median operative time gradually decreased from 95 (interquartile range, IQR, 85–110) minutes for the early group to 70 (IQR, 60–80) minutes for the late group ( P < .000), and an asymptote was reached after approximately 35 cases. After surgery, the VAS for leg pain (LP) and ODI decreased significantly and remained constant during the follow-up. However, the VAS of low back pain (LBP) increased mildly. The total complication rate was 6.6%. ODI, VAS of LP and of LBP, and complication rate did not significantly differ between two groups. Early ambulation and short hospital stay after surgery were achieved. Conclusion The learning curve of PETD for LSS was assessed and good clinical results were achieved. The surgeon’s experience with this technique correlated with reduced operation time. Proper patient selection, familiarity with pathological anatomy, and manipulation under endoscopic view may shorten the learning curve and decrease complications.