A single institution experience with 85 consecutive robotic-assisted pelvic dissections

Jennifer E Hrabe, MD, Mary Charlton, PhD, John C Byrn, MD. University of Iowa.

Introduction
The purpose of our study was to analyze our first 85 robotic-assisted pelvic dissections performed for benign and malignant colorectal disorders and assess learning curve and cost. Though robotic and robotic-assisted laparoscopic procedures in colorectal surgery have garnered much attention, wide adaptation of the technology has not been achieved. We aim to contribute our experience with this technique.

Methods and Procedures
Following IRB approval, a retrospective chart review of 85 consecutive robotic-assisted pelvic dissections performed between 9/1/2010 and 12/31/2012 was conducted. Patient demographic, clinicopathologic, procedure, and complication data was gathered, and cost data was obtained from the University HealthSystem Consortium (UHC) clinical database. The first 43 cases (“Time 1”) were compared to the next 42 cases (“Time 2”) in regards to patient characteristics, short-term operative outcomes, operating times, and costs. Observed direct hospital costs were compared to expected direct hospital costs which were calculated based on patient characteristics. An observed:expected direct hospital costs ratio of 1 indicates observed costs equaling expected costs. Chi-square and Fisher’s exact tests for categorical variables and t-tests for continuous variables were used to compare demographic variables, clinical characteristics and outcomes of interest.

Results
Of the 85 patients undergoing robotic-assisted pelvic dissection, the indication for surgery was cancer for 51 patients (60%), inflammatory bowel disease for 18 (21%), and rectal prolapse for 16 (19%). The most commonly performed procedures were low anterior resection (n=25, 29.4%) and abdominoperineal resection (n=21, 24.7%). The only statistically significant difference between patients in the two groups was a higher mean body mass index (BMI) for Time 2 (26.1 kg/m2 for Time 1 vs. 29.4 kg/m2 for Time 2, p=0.02). Complication and conversion rates did not differ between the two groups and there were no mortalities reported within the first 30 days. Mean operating time was significantly shorter for Time 2 (266.9 minutes for Time 1 versus 224.4 minutes for Time 2, p < 0.05). Though it did not reach statistical significance, the mean observed direct hospital cost showed a trend of decreasing ($17,349 for Time 1 versus $13,680 for Time 2, p>0.05). The observed:expected cost ratio significantly decreased (1.47 for Time 1 versus 1.05 for Time 2, p=0.007).

Conclusions
Our initial experience with robotic-assisted pelvic dissections demonstrates clear improvement in operating times despite a higher mean BMI in the later group of patients. Additionally, a trend towards decreasing cost was demonstrated. Future studies to compare cost, profitability, and patient outcomes to open and traditional laparoscopic approaches will be important for a further understanding of the benefits of robotic colorectal surgery.