Effect of surgical technique on pain and narcotic use after robot-assisted and open distal pancreatectomy

Ammara A Watkins, MD¹, Sjors Klompmaker¹, William E Gooding², Manuel Castillo-Angeles¹, Yufei Liu, PhD¹, Jennifer F Tseng, MD, MPH¹, Mark P Callery, MD¹, Tara S Kent, MD¹, A. James Moser, MD¹. ¹Pancreas and Liver Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, ²Biostatistics Facility, University of Pittsburg Cancer Institute

Introduction: Multiple studies demonstrate equivalent outcomes after robot-assisted distal pancreatectomy (RADP) compared to open (ODP). Published data evaluating postoperative quality of life after RADP are limited to surrogate markers such as length of stay.  We hypothesized patients undergoing RADP experience less postoperative treatment burden relative to ODP as measured by pain scores and narcotic use.

Methods: Retrospective (July 2009-March 2014) single-institution analysis of 0-10 numeric pain rating scale (NPS) and total morphine equivalents per 24 hours after distal pancreatectomy through postoperative day (POD) #5. Laparoscopic distal pancreatectomy was excluded due to limited volume. The ODP cohort comprised two groups due to standard of care epidural analgesia: ODP with epidural (analyzed as intent to treat) and ODP without epidural. The RADP cohort received parenteral narcotics alone. Marginal regression analysis analyzed the effect of epidural analgesia on daily narcotic use. 

Results: Of 117 patients, 84 had complete NPS and narcotic data. There were 50 patients who underwent ODP with epidural, 11(18%) underwent ODP without epidural and 23(27%) underwent RADP. NPS resembled statistical noise and were uninformative (data not shown). A mixed effects linear model for repeated measures was developed, validated, and applied to daily mean pain scores and narcotic use to evaluate trends over time. Differences evolved in a time-dependent manner consistent with recovery from a surgical procedure. Predicted mean narcotic use was greatest on the day of surgery after ODP without epidural compared to RADP and ODP with epidural (p<0.05, figure 1).  On POD 1 and 2, narcotic use was greater after RADP or ODP without epidural compared to ODP with epidural (p<0.05). By POD 3-4, all three groups had equivalent narcotic requirements. By POD 5, narcotic use after RADP had decreased significantly and was equivalent to ODP with epidural (p<0.05). Regression analysis indicated that epidural analgesia reduced daily narcotic use by 28% after ODP.  

Conclusion: Over the six-day observation window, patients undergoing ODP with epidural had the least narcotic use. Patients undergoing RADP require less narcotic than ODP without epidural analgesia. Patients undergoing RADP had peaked narcotic use on POD 1-2 and demonstrated a rapid decrease in narcotic use by POD 5 compared to ODP without epidural. We conclude that additional attention to pain management is required after RADP. Epidural analgesia has a narcotic sparing effect but is not ideal for minimal-access surgery. Patients undergoing RADP may benefit from regional analgesia in the immediate postoperative anesthesia to optimize their recovery.