The Efficacy of Transversus Abdominis Plane Block for Abdominal Hysterectomy Post-operative Analgesia

Introduction/background Abdominal hysterectomy is an open surgical procedure associated with considerable post-operative pain. Narcotics are often required during patient recovery but can result in adverse side effects. Transversus abdominis plane block (TAP block) is a regional anesthetic technique that is found to be an effective post-operative analgesia for many types of abdominal surgeries, including abdominal hysterectomies. However recent literature shows contradicting results regarding TAP block’s analgesic effect on recovery from abdominal hysterectomies. This study investigated the efficacy of TAP block to reduce narcotic consumption and improve pain scores in abdominal hysterectomy patients. Methods A single-center retrospective cohort study was performed. The inclusion criteria was patients who underwent abdominal hysterectomy at Winnie Palmer Hospital for Women & Babies (WPH) between January 12, 2015 and December 31, 2015. Exclusion criteria were patients who received a second surgery within the same hospitalization, experienced an in-hospital mortality event, received hysterectomy for known malignancy, stayed in the hospital less than 24 hours, and whose charts contained missing data points. Data collected were: age, weight, height, body mass index (BMI), length of hospital stay, total narcotic consumption (intra-operation, in the post-anesthesia care unit (PACU), first 24 hours after admittance, during entire hospital stay, total patient-controlled analgesia (PCA) quantity, and total oral narcotics quantity. All narcotics were converted into parental morphine units for analysis. Numeric pain rating scale (NPRS) scores at two, four, eight, 12, 16, 20, and 24 hours after leaving the PACU were collected. Two-tailed paired T-test was performed to compare the narcotic consumption and pain scores between the TAP block group and the non-TAP block group. Results WPH used ultrasound-guided bilateral TAP block for patients undergoing abdominal hysterectomies. 63 patient charts were evaluated with 32 in the TAP block group and 31 in the non-TAP block group. Narcotic consumption was significantly different in the PACU with TAP block group consuming less narcotics than non-TAP block group (5.05 vs 8.65 IV morphine equivalents, p=0.012). TAP block group’s mean narcotic consumption was not significantly lower than Non-TAP block group’s mean consumption during intra-operation, first 24 hours after admittance, and total hospital stay (p=0.419, p=0.533, p=0.754 respectively). Mean NPRS scores at all hours (2, 4, 8, 12, 16, 20, and 24) displayed no statistical difference between the two groups. Total patient-controlled analgesia (PCA) and total overall oral narcotic usage showed no statistically significant differences between TAP block group and Non-TAP block group (p=0.252, 0.669 respectively). Conclusion The results of this study demonstrated that TAP block did reduce narcotic requirement in the PACU but did not exhibit superior analgesic efficacy after discharge from the PACU, nor reduce the total length of hospital stay.