Superior Hypogastric Nerve Plexus Block With Bupivacaine for Postoperative Pain Reduction Following Robotic Assisted Resection of Endometriosis: A Randomized Control Trial

This clinical study will recruit patients at their preoperative visit. If the surgery is Davinci single incision laparoscopic surgery (or single incision plus one port) for resection endometriosis, the subject will be informed about the clinical trial, as well as risks and benefits of enrolling by the fellow or attending surgeon. The pre-op visit is typically 1-4 weeks before the day of surgery. They can make the decision either the day of the pre-op visit or they can have time to consider it and inform us of their decision on the day of surgery. If they agree to participate in the trial, they will be consented for the procedure and for enrollment in the trial. The subjects that agree will be assigned a number to de-identify data and then randomly assigned to the placebo or interventional treatment group with use of a computer generator (RedCap). The clinician will be aware of the group that they are in but the subject will not be aware of the group assignment.

At the time of enrollment the subject will also be informed that their medical record will be accessed to obtain information from the surgery and demographics. They will be informed that this information will be de-identified and entered into a password protected database called RedCap. The subject information obtained that will be demographics including those obtained from their pre-operative visit clinic note such as: age, race and ethnicity, gravidity/parity, surgical history, preoperative visual analog scale (VAS) score. As well as the information obtained from the operative note: stage of endometriosis diagnosed, additional laparoscopic procedures performed during the surgery, operative time, estimated blood loss, major intraoperative complication, uterine weight, and pathology. Their medical records will be reviewed by members of the surgical team at the time of surgery, at their postoperative visit, and during data analysis, so three times total.

During the case, The trocar used for the robotic single site surgery is the Single-Site port with curved cannulas made for the DaVinci XI single site instruments. This is inserted through one incision in the umbilicus. If the patient has severe endometriosis, a right lower quadrant 8mm trocar is inserted. This is standard of care for robotic assisted single site resection of endometriosis.

For the block portion of the study, the placebo group will have 5cc of 0.9% normal saline injected superficially into the retroperitoneal space overlying the superior hypogastric nerve plexus just distal to the common iliac bifurcation, bilaterally (10cc normal saline total). The nerve plexus bifurcation will be identified by the sacral promontory and the injection region will be approximately 1-2cm below this area bilaterally. The interventional treatment group will have 5cc total of diluted 0.25% bupivacaine hydrochloride injected at the same location (10cc total).

We will perform the superior hypogastric nerve block with 10cc of 0.25% Bupivacaine Hydrochloride as this is the most common analgesic used for this block. Bupivacaine Hydrochloride is FDA approved for subcutaneous nerve blocks at concentrations of 0.25% and 0.50%. The Texas Children's Hospital Pharmacy is familiar with 0.25% Bupivacaine Hydrochloride as it is a commonly used medication in the operating room and is already present in the endometriosis resection set as it is typically injected in the incision sites after the surgery. The subject will be blinded to the group they are randomized to (either placebo or investigative treatment), but the operating room nurses and physicians will not be blinded. The surgical team will look at what group the subject is assigned to before the case and either ask for the nurse to get the 0.25% Bupivacaine Hydrochloride or a saline filled 10cc syringe. If they are In the 0.25% Bupivacaine Hydrochloride group, no additional medication will be ordered as it is already in the set.