TAP vs Surgical Infiltration of Local Anesthetic in Laparoscopic and Robotic Hysterectomy

Overview

Laparoscopic and Robotic assisted hysterectomy is a surgical procedure that is a minimally invasive way in which to remove the uterus, which has less scarring and fewer complications. However, this procedure, much like its open-surgical counterpart, is often associated with significant post-operative pain. To augment this pain there are many different analgesic techniques available to offset pain. Ultrasound-guided transversus abdominis plane (TAP) block is one such procedure involving the injection of a local anesthetic into the plane of the transversus abdominal muscle where the terminal branches of nerves lie. A similar, yet different analgesic approach is that of direct injection of local anesthetic into the incision by the surgeon during or just after surgical procedures. These two approaches have both been proven to decrease post-operative pain in patients for many procedures, but never compared to one another.

This is a double blinded randomized study. All patients will receive one form of local anesthetic pain relief either from TAP or infiltration. Patients will be randomized to one of two study arms in a double-blinded, placebo controlled study. All patients will receive a TAP infiltration and all patients will receive infiltration into the incision. In one arm the TAP infiltration will contain 10 mL of 0.25 % bupivacaine with epinephrine injected followed by 20 mL of a 50:50 mixture of liposomal bupivacaine and normal saline. This will then be repeated on the contralateral side. In the same arm the surgeon infiltration into the incision will consist of 10 ml of normal saline per port site, 5 ml prior to incision and 5 ml prior to closure at each port site. In the second arm the bilateral TAP infiltration will consist of 30 mL of normal saline per side. In the same arm the surgeon infiltration will consist of 10 mL of 0.25% bupivacaine per port site. The surgeon infiltration will consist of 5 ml of 0.25% bupivacaine prior to incision and 5 ml of 0.25% bupivacaine prior to closure at each port site. A TAP infiltration is an injection of local anesthetic under the covering of the transversus abdominis muscle layer which provides effective post operative analgesia.2-5 This layer is found using an ultrasound, which is a beam of high frequency sound that allows one to visualize images in the body. Then using this ultrasound the investigators can see our needle as it pierces the covering of the transversus abdominis muscle layer and watch as the local anesthetic is infiltrated into this plane. This is done on both sides of the abdomen to provide analgesia to the skin, muscle, and facial layers of the abdomen. This is currently standard of care at our institution and will be performed within one hour of surgical incision. The injection will consist of 10 mL of 0.25% bupivacaine with epinephrine followed by 20 mL of liposomal bupivacaine saline mixture or 10 ml of saline followed by 20 ml of saline and then repeated on the contralateral side. Surgical Infiltration of the study solution will be performed both prior to incision and at the end of surgery just prior to closure of incisions. At each time, the surgeon will inject 5 mL of 0.25% bupivacaine into each of the port site incisions. Investigational Drug Service (IDS) pharmacy will be charged with the blinding of medications vs. saline for these procedures. Following the procedure, all individuals will receive scheduled acetaminophen (1 gram every 6 hours), scheduled ibuprofen (800 mg every 8 hours), and PRN oxycodone 5-10mg q4h if pain is rated at more than 5 out of 10 on a numerical pain scale.