Completion of a Liver Surgery Complexity Score and Classification Based on an International Survey of Experts

Abstract

Background: Liver resections have classically been distinguished as "minor" or "major," based on number of segments removed. This is flawed because the number of segments resected alone does not convey the complexity of a resection. We recently developed a 3-tiered classification for the complexity of liver resections based on utility weighting by experts. This study aims to complete the earlier classification and to illustrate its application.

Study design: Two surveys were administered to expert liver surgeons. Experts were asked to rate the difficulty of various open liver resections on a scale of 1 to 10. Statistical methods were then used to develop a complexity score for each procedure.

Results: Sixty-six of 135 (48.9%) surgeons responded to the earlier survey, and 66 of 122 (54.1%) responded to the current survey. In all, 19 procedures were rated. The lowest mean score of 1.36 (indicating least difficult) was given to peripheral wedge resection. Right hepatectomy with IVC reconstruction was deemed most difficult, with a score of 9.35. Complexity scores were similar for 9 procedures present in both surveys. Caudate resection, hepaticojejunostomy, and vascular reconstruction all increased the complexity of standard resections significantly.

Conclusions: These data permit quantitative assessment of the difficulty of a variety of liver resections. The complexity scores generated allow for separation of liver resections into 3 categories of complexity (low complexity, medium complexity, and high complexity) on a quantitative basis. This provides a more accurate representation of the complexity of procedures in comparative studies.

Figure 1

The adjusted mean complexity score and 95% confidence interval for each type of liver resection included in the survey. (A) Peripheral wedge resection; (B) left lateral sectionectomy; (C) left hepatectomy without caudate resection; (D) right hepatectomy; (E) right posterior sectionectomy; (F) left hepatectomy with caudate resection; (G) isolated caudate resection; (H) right trisectionectomy; (I) right anterior sectionectomy; (J) right hepatectomy with caudate resection; (K) right hepatectomy with hepaticojejunostomy; (L) anatomic middle hepatectomy; (M) right trisectionectomy with caudate resection; (N) left trisectionectomy without caudate resection; (O) right trisectionectomy with hepaticojejunostomy; (P) left trisectionectomy with caudate resection; (Q) right hepatectomy with portal vein reconstruction [main to left]); (R) right trisectionectomy with portal vein reconstruction [main to left]; (S) right hepatectomy with IVC reconstruction.

Figure 2

Effect on complexity score of addition of caudate resection to: (A) Right hepatectomy; (B) left hepatectomy; (C) right trisectionectomy; (D) left trisectionectomy. In each case the solid curve indicates the results for a procedure without caudate resection and the dotted curve the results for the same procedure with caudate resection added. The horizontal axis is the complexity score and the vertical axis is the number of surgeons who selected a particular score. The thin solid vertical line where it intersects the horizontal axis indicates the mean score for each procedure without caudate resection. The thick vertical line where it intersects the horizontal axis is the mean score for each procedure with caudate resection. The horizontal arrow depicts the shift in the mean score when caudate resection was added to each procedure. The p value indicates the significance of this difference.

Figure 3

Effect on complexity score of addition of hepaticojejunostomy to: (A) Right hepatectomy; (B) right trisectionectomy. Axes and lines as for Figure 2

Figure 4

(A) Effect on complexity score of addition of portal vein resection and reconstruction to right hepatectomy; (B) effect of addition of portal vein resection and reconstruction to right trisectionectomy; (C) effect of addition resection and reconstruction of the inferior vena cava to right hepatectomy. Axes and lines as for Figure 2.