The Use of Paravertebral Nerve Blocks in Immediate Breast Reconstruction following Mastectomy: A Canadian Hospital-Perspective Cost Effectiveness Analysis
Michael J. Stein, MD, Angel Arnaout, MD MBA, Kednapa Thavorn, MSc PhD, Patrick Wong, MD, Tim Ramsey, PhD, Jing Zhang, MD PhD.
University of Ottawa, Ottawa, ON, Canada.
The increasing popularity of immediate breast reconstruction and a shifting focus towards ambulatory breast surgery has been met with growing regulatory pressures for quality assurance, patient satisfaction and cost-effectiveness. In an effort to optimize postoperative pain control following breast reconstruction, Paravertebral Blocks (PVB), have emerged as promising adjuncts to standard analgesic protocols. Studies on the efficacy and economic implications of PVB's are limited, specifically the tradeoff between its clinical impact and incremental cost associated with delivering the service. Our objective was to evaluate the cost-effectiveness of PVB's for the prevention and treatment of acute pain in patients undergoing breast reconstruction post mastectomy at a large tertiary care academic hospital in Canada.
We retrospectively studied all patients who underwent immediate alloplastic breast reconstruction from 2010-2016. Data included the use of PVB, postoperative serial pain intensity scores, postoperative narcotic usage and length-of-stay in PACU. A cost-effectiveness analysis based on a net-benefit regression model was used to assess whether, from a hospitals perspective, the benefit gained from performing a PVB outweighed its additional costs compared to standard analgesia alone. The health outcome of interest was the average self-reported post-operative pain score. We also performed a sub-group analysis wherein we calculated the cost-effectiveness of specific patient cohorts according to laterality and type of mastectomy, extent of lymph node dissection and weather it was an expander or implant based.
A total of 298 patients undergoing immediate breast reconstruction following mastectomy met inclusion criteria. Of these, 112(38%) patients underwent standard analgesic protocols and 186(62%) underwent PVB, in addition to standard analgesic protocols. Patients who received a PVB had significant reductions in average pain scores (2.8 vs 3.3, p=0.002), total opiate usage (52units vs 63units) (p=0.038) and length of stay in PACU (92min vs 142min) (p=0.0228). The cost-effectiveness base case results show that, for the average breast reconstruction patient, a PVB is associated with a net positive benefit to the hospital if the hospital values a unit reduction in a patient's pain score at about $2,000 or more. Sub-group analyses demonstrate that cost-effectiveness of PVB's vary significantly depending on the extent of the procedure. More specifically, a u-shaped relationship exists between the Incremental Cost Effectiveness Ratio (ICER) of the PVB and the invasiveness in subtype of immediate breast reconstruction.
The present study demonstrates that PVB's are safe and effective at reducing narcotic usage, subjective pain and length of stay in the recovery room. Despite these promising results, a hospital perspective economic analysis is essential to ensure that such an intervention is cost-effective, particularly in the context of the Canadian public healthcare system. We illustrate here that a U-shaped relationship exists between ICER's and the extent of the immediate breast reconstruction, thereby demonstrating that such an intervention may only be cost effective in certain patient populations. To the best of our knowledge this is the first study to critically evaluate the cost-effectiveness of PVB's for immediate breast reconstruction in Canada and will hopefully inform future prospective randomized trials on PVB's in breast reconstruction.
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