Open Versus Laparoscopic Colectomy for Patients With Endoscopically Unresectable Polyps. the Effect of Conversion

Nawar A Alkhamesi, MD PhD FRCSGenSurg FRCS FRCSEd, Micheal V Lebenbaum, MSc, Sisira Sarma, PhD, Janet Martin, PhD, Christpher M Schlachta, BSc MD CM FRCSC FACS. Department of Surgery and Department of Epidemiology & Biostatistics, Schulich School of Medicine, University of Western Ontario

Objective
Cost analysis of elective laparoscopic versus open colon resection in patients with endoscopically unresectable polyps was performed to evaluate relative costs of both surgeries. A decision tree incorporating parameters from this patient sample was created to examine the possible effects of including disability related costs and to determine which variables the costs were most sensitive to.

Method
Retrospective review of elective laparoscopic and open segmental colectomies between January2005 and April 2010 for patients with unresectable polyps was performed. Combined cases and procedures carried out on inpatients were excluded to minimize cost variables. The hospital case costing system was used to calculate capital and hospital stay cost. The cost of disposable equipment was calculated manually. Examination of the possible effects of including disability related costs was done by applying partial and full recovery times derived from the literature in a decision tree. Estimation of costs was conducted by applying full-time wage rate for time until partial recovery and part-time wage rate to the remaining time until full recovery.

Result
Total sample size was 79 (34 laparoscopic, 45 open colectomy). Median operating room time was longer for laparoscopic than open (169 vs. 133 minutes; p=0.004). Mean disposable costs were greater for laparoscopic than for open ($1777.56 vs. $1028.37). Overall direct surgical costs were greater for laparoscopic than open surgery ($5407.63 vs. $3741.45; p<0.0001 for median). Complication risk was similar (35.3% vs. 33.3%; p=0.8). In total, 23.5% of laparoscopic surgeries were converted to open. Median hospital stay during index admission was shorter after laparoscopy versus open (5 vs. 6 days; p =0.02); however, due to readmissions for complications, the mean cost of hospital stay throughout the study period was higher for laparoscopic vs. open ($5412.71 vs. $4615.00). Mean total hospital cost including supplies, index admission cost, and readmission cost was greater for laparoscopy than for open ($11703.66 vs. $8597.85), although median costs were not significantly different (p = 0.23). Conclusions regarding total costs remained robust after post-hoc sub analysis for right versus left colectomy. After inclusion of disability costs, laparoscopic surgery remained more costly than open surgery ($14801 vs. $12737). There was one far outlier in the laparoscopy group, and its exclusion reduced the estimate of total cost to $13912. With this exclusion, one way sensitivity analyses suggested that costs were only sensitive to conversions. A 10% decrease in conversions would reduce the probability of readmission, and would bring costs of laparoscopy in line with open surgery or cheaper.

Conclusion

This analysis shows that costs were higher in the laparoscopic group and are sensitive to conversions. Due to the small sample size, outliers had strong effects on the results. In addition, the non-randomized nature of the study makes it difficult to draw definitive conclusions from the sample. RCTs with larger sample sizes may clarify this decision in this particular patient population.

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