Association between the computed tomography findings and operative time for interval appendectomy in children

Abstract

Purpose: The purpose was to evaluate the association between operative time and findings noted on computed tomography (CT) immediately before interval appendectomy.

Materials and methods: Forty-two children who underwent CT before interval appendectomy were included. We evaluated the association between operative time and these image findings: (1) appendicolith, (2) increased intra-abdominal fat density around the appendix, (3) location of the appendix, (4) ascites, (5) abscess formation and (6) maximum appendix outer wall diameter. Appendix location was classified as (#1) just below the anterior abdominal wall; (#2) retrocaecal or retro-ascending colon and (#3) pelvic. Results were analysed using Pearson's correlation coefficient or Mann-Whitney U test.

Results: The mean patient age and operative time were 116.24 ± 38.66 months (range, 31-195) and 67.76 ± 31.23 min (range, 30-179), respectively. Ascites was detected in only one case, and no abscess occurred in any patient; therefore, these findings were not analysed. Factors that significantly prolonged the operative time included increased intra-abdominal fat density around the appendix (absent, 59.43 ± 22.14 [range, 30-108] vs. present, 84.43 ± 40.13 [range, 32-179] min; P = 0.03) and retrocaecal or retro-ascending colon appendix (location 1, 40.83 ± 8.35 [range, 30-50]; location 2, 99.25 ± 18.56 [range, 74-135]; location 3, 64.54 ± 30.22 [range, 30-179] min; P < 0.01). There was a weak but significant association between maximum appendix outer wall diameter and operative time (R = 0.353; P = 0.02).

Conclusion: These pre-operative CT findings are important predictors of operative time for interval appendectomy. Radiologists and surgeons should use these specific image findings to predict the operative time and need for additional procedures during an interval appendectomy.

Keywords: Acute appendicitis; computed tomography; interval appendectomy; operative time; transumbilical laparoscopic-assisted appendectomy.

Figure 1

A 121-month-old female patient was 140 cm tall and weighed 34 kg. The operative time was 135 min. The interval between symptom onset and appendectomy and between computed tomography and appendectomy was 113 days and 7 days, respectively. (a) Axial computed tomography image shows that the appendicolith (open arrow) and appendix are surrounded by increased intra-abdominal fat density (arrow heads) and the maximum outer diameter of the appendix is 15 mm. (b) Axial computed tomography image shows that the appendix (open arrow) is located in the retro-ascending colon (white arrows). Appendix location is classified as 2

Figure 2

An 81-month-old female patient was 115.3 cm tall and weighed 15.19 kg. The operative time was 45 min. The intervals between symptom onset and appendectomy and between computed tomography and appendectomy were 106 days and 7 days, respectively. (a) Axial computed tomography image shows that the appendix (open arrow) is located just below the anterior abdominal wall. Appendix location is classified as 1. An appendicolith is not detected. (b) Axial computed tomography image shows that the appendix (open arrows) is surrounded by increased intra-abdominal fat density (arrow heads), and the maximum outer diameter of the appendix is 8 mm (double-headed arrow)

Figure 3

A 175-month-old female patient was 148.5 cm tall and weighed 45.5 kg. The operative time was 30 min. The intervals between symptom onset and appendectomy and between computed tomography and appendectomy were 109 days and 5 days, respectively. (a) Axial computed tomography image shows that the appendix (open arrow) runs towards the pelvis. The ventral side is covered by the small intestine (white arrow). Appendix location is classified as 3. (b) Axial computed tomography image shows that the appendix leaves the caecum (white arrow). The appendix (open arrows) is not surrounded by increased intra-abdominal fat density, and the maximum outer diameter of the appendix is 4.7 mm