Pilot: Intraoperative TAP Block and Post-operative Pain Control for Minimally Invasive Hysterectomy for Endometrial Cancer

The investigators believe that the disappointing results thus far with TAP blocks in minimally invasive hysterectomy may relate to several factors. A combination of short and long-acting anesthetic agents may provide the optimal analgesic effect. Large volumes of injection may promote spread of the anesthetics for better coverage, especially as long-acting agents are known to diffuse minimally. Lastly, multiple injections may provide better coverage of the nerves that innervate the abdominal wall. The investigators also believe that laparoscopic TAP blocks, administered by the surgeon, have advantages over the more commonly used ultrasound-guided approach typically performed by anesthesiologists. The laparoscopic approach is quick, on the order of a few minutes, whereas the ultrasound approach can be time-consuming. There is also less risk of visceral injury since the injection is performed under direct laparoscopic view. There are now 2 randomized studies suggesting that the laparoscopic approach is equivalent to the ultrasound approach. An additional potential reason why most studies have been negative is that patients undergoing minimally invasive hysterectomy do not generally experience severe pain, making it more difficult to demonstrate pain reduction with any given intervention. However, the studies to date do indicate that these patients experience moderate pain and do use opiates. An intervention that markedly reduces or even eliminates opiate use would be of potential benefit. The investigators have used a TAP block technique that is performed intraoperatively by the surgeon under direct laparoscopic view. The investigators use a mixture of plain and liposomal bupivacaine injected at multiple sites and in large volume to distribute the drugs widely, potentially resulting in longer and improved efficacy. This method has not been previously studied in a randomized trial. The investigators propose to demonstrate that this technique markedly decreases opiate usage and pain scores in patients undergoing minimally invasive hysterectomy.