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![A skill degradation in laparoscopic surgery after a long absence: assessment based on nephrectomy case](https://image.oaes.cc/83197cc5-424d-4ab5-a7ac-62e4fa97d628/2532.fig.1.png)
Figure 1. Relationship between laparoscopic time and interval days of laparoscopic nephrectomy/nephroureterectomy depicted by the restricted cubic spline curve method. The grey zone is the 95% confidence interval. Laparoscopic time increased significantly according to the interval days (P = 0.003; nonlinearity P = 0.021)