64. Intravenous vs oral acetaminophen administration in perioperative care of one- and two-level LLIFs with instrumented posterior lumbar fusion: a comparative effectiveness study

BACKGROUND CONTEXT Since 2000, the annual death toll from opioid associated overdose has increased by over 300%. To reduce the opioid consumption, physicians have used alternative approaches, which have proven to not only be effective, but also reduce the side effects such as nausea, constipation, and addiction. IV acetaminophen has been shown to successfully accomplish the reduction in opioid use, however, it is an expensive alternative. Testing the efficacy of IV acetaminophen vs its oral formulation will likely modify future postoperative pain management regimens while also addressing cost-effectiveness. PURPOSE To prospectively evaluate clinical outcomes and determine the cost effectiveness of IV vs oral (PO) acetaminophen following lumbar circumferential spine surgery. We hypothesize that IV acetaminophen will perform better than PO in terms of length of stay, morphine equivalence, and change in VAS scores from baseline. STUDY DESIGN/SETTING A prospective, single-center, randomized control trial. PATIENT SAMPLE Patients between the ages of 18-85 who underwent circumferential lumbar fusion surgery, while failing conservative treatment for more than 6 months were included in the study. Patients were excluded if they had already undergone lumbar surgery at the index level(s), were diagnosed with osteoporosis, had dysphagia prohibiting oral administration, or had a history of substance abuse. OUTCOME MEASURES Outcome measures included opioid equivalence, length of hospital stay, VAS measurements, and Oswestry Disability Index (ODI) scores. METHODS Once enrolled, patients were randomized to either the IV or PO acetaminophen treatment groups. Preoperatively, patients completed a baseline analgesic regimen questionnaire, surveys including VAS, SF-12, and ODI, and were administered their first acetaminophen dose within three hours of first incision. Postoperatively, patients received seven subsequent doses of their assigned acetaminophen, with access to supplemental analgesics if needed. Analgesic usage and VAS scores were monitored until discharge. Surveys were completed at six weeks and six months follow-up. RESULTS Average daily opioid consumption for the IV group was significantly lower than the PO group during the immediate postoperative period. Average length of stay was similar between groups, 3.3 days for PO and 3.7 days for IV. VAS back and leg scores were not statistically different between groups, however, both groups experienced a decrease by more than the minimally clinically important difference (MCID) of 12 points from baseline. ODI also decreased by the MCID at the 6-month follow-up, which was defined as 12.8% for ODI. CONCLUSIONS Along with an overall reduction in opioid usage, patient-reported outcomes depict successful improvement of pain management with the use of IV acetaminophen following circumferential spinal fusion surgery. Furthermore, despite the large discrepancy between the two formulations in cost-to-perceived-benefit ratio, the significant reduction of opioid usage and, therefore, its associated costs, provides a far less dramatic divergence. The continued testing of the efficacy of IV acetaminophen vs its oral formulation will likely modify future postoperative pain management regimens while also addressing the opioid epidemic plaguing communities across the US. FDA DEVICE/DRUG STATUS OFIRMEV (Approved for this indication).