1. Leung, T.W. MD; Dixon, Elijah MD, BSc, MSc; Gill, Manpreet BSc; Brett D. BSc; Moulton, Kyle M. BHSc; Kaplan, Gilaad G. MD, MPh; MacLean, Anthony R. MD, FRCS(C), FACS Annals of Surgery: Volume 250(1), July 2009, pp51 -53

2. Objective Post – appendectomy SBO in adult population SBO rate b/w open and lap appendectomies Retrospective study Administrative discharge database (QSH) April 1, 1999 and March 31, 2002 ICD – 9 Codes Cohort of 2598 patients 2332 met inclusion criteria 1777 charts reviewed Further Admissions for BO ICD–9 prior to march 2002 ICD–10-CA after march 2002 5 year follow up Exclusions No residency data over 5yr follow up Appendectomies from unrelated procedures (91) None Available charts (555) Analysis Logistic regression: Odd ratio for potential risk factors for developing SBO Univariate screening to determine covariates to include (P < = 0.20) Variates with P < = 0.10 were retained Two sided P value of less than or equal to 0.05 was considered significant Stratification of result as follows

3. Result TABLE 1. Patient Demographics, Surgical Approach, and Pathology N Percent (%) Male 894 50.3 Female 883 49.7 Previous abdominal surgery 291 16.4 Immunosuppression 58 3.3 Surgical approach RLQ* 969 54.5 Midline 220 12.4 Laparoscopic 588 33.1 Operative description of appendix Normal 253 14.6 Suppurative 1328 76.8 Perforated 138 8.0 Other† 11 0.6 *RLQ indicates right lower quadrant. †Other: cancer, fibrosis. TABLE 2. Risk Factors for SBO Risk Factor Odds Ratio 95% C.interval Midline laparotomy 5.4 2.8–10.4 Chronic append, cancer* 7.4 2.7–20.3 Normal appendix* 3.8 1.7–8.6 Perforated appendicitis* 3.1 1.5–6.6 *Based on operative findings.

4. Figures Figure 1. Rates of SBO by surgical approach P < 0.0001 Figure 2. Rates of SBO by operative description, P = 0.0015. *Other = Ca, Fibroid

5. Conclusion Overall rate for SBO was 2.8% (0.16 to 10.7%) 0.0069 cases per person per year. Greatest risk factors Midline incision Normal Appendix Perforated Appendix Non appendicitis pathology Non statistically significant difference in SBO rates following lap appendectomy compared with open approaches.