In the January issue of the Archives, Bennett et al1 described a prospective analysis of 1194 patients undergoing laparoscopic-assisted colorectal surgery.1 The rate of postoperative complications with operations performed by high-volume (>40 procedures) surgeons was significantly lower than with operations performed by low-volume (<40 procedures) surgeons (9.9% vs 18.6%, P<.001). The authors assert that these findings support the presence of a "learning curve" for laparoscopic-assisted colectomy.
However, a close examination of the data suggests otherwise. The authors used volume as a dichotomous variable (high vs low), and their cutoff point (40 procedures) was defined retrospectively. Had the authors selected a different volume threshold, their conclusions would have been different. Furthermore, if the analysis were performed using volume as a continuous variable, a learning curve would not have been discernible at all. In fact, if the numbers reported in the article's Table are used to plot volume vs
Finlayson SRG, Birkmeyer JD. The Learning Curve for Laparoscopic Colorectal Surgery. Arch Surg. 1997;132(8):931. doi:10.1001/archsurg.1997.01430320133025