Intraoperative Transversus Abdominis Plane Block for Gynecologic Surgery (GYNTAP) (GYNTAP)

Intraoperative Transversus Abdominis Plane Block for Gynecologic Surgery (GYNTAP): Modifying an Existing Technique for Ease of Administration and Increased Accuracy

This study attempts to learn about the effectiveness of a modification to the Transversus Abdominis Plane (TAP) block that works by anaesthetizing the sensory afferents of the abdominal wall postoperatively using ultrasound guidance. The investigators want to see if regional blocks placed by the surgeon intraoperatively to assure regional anesthetic spread in the appropriate plane could reduce error and improve postoperative recovery.

This study is a prospective, randomized blinded study that investigates the efficacy of a transversus abdominis plane block under direct view. In this pilot study involving gynecologic patients undergoing open (abdominal wall incision either vertically or horizontally) hysterectomy or other related gynecologic surgery, the investigators will use ropivacaine versus saline for the placebo control group, which in both groups involves injection of agent directly into the appropriate fascial layers prior to abdominal wall closure. Efficacy is to be assessed via measurement of pain scores, nausea and vomiting, and opioid consumption in both participant groups. The number of dermatomes which are blocked in both participant groups during the first 24 hours following surgery will be recorded.

Study participants will undergo intraoperative transversus abdominis plane (TAP) block with the syringe of medication supplied by the pharmacy using a syringe with attached spinal needle between the transversus abdominis and internal oblique. The spinal needle will be threaded horizontally and as far laterally at the superior aspect of the vertical axis of the incision as possible within this space and anesthetic will be injected after an initial pull back on the syringe to ensure there is no arterial exposure as per the following schedule: Weight <70kg: Ropivacaine 75mg - 150 mg on each side (20mL ropivacaine 3.75mg/ml each side) Weight greater than or equal to 70kg: Ropivacaine 100mg - 200mg on each side (20mL ropivacaine 5mg/ml each side

Study participants will undergo intraoperative transversus abdominis plane (TAP) block with the syringe of medication supplied by the pharmacy using a syringe with attached spinal needle between the transversus abdominis and internal oblique. The spinal needle will be threaded horizontally and as far laterally at the superior aspect of the vertical axis of the incision as possible within this space and the placebo solution will be injected after an initial pull back on the syringe to ensure there is no arterial exposure as per the following schedule: Weight <70kg: 20mL each side Weight greater than or equal to 70kg: 20mL each side

The amount of diludid received per participant will be recorded from participant medication record at the specified time frame.

The investigator will complete dermatomal assessments at the specified time frames by using a stimulus in the area of the transversus abdominis plane block to determine the effectiveness of the block.

Pain severity will be measured using a validated Numerical Rating Scale with 0cm=no pain and 10cm=worst pain imaginable.

Nausea will be measured using a validated postoperative nausea and vomiting scale known as the Impact Scale.

Inclusion Criteria: Age≥18 years old and not pregnant Must be able to provide informed consent - functional understanding of English Undergoes exploratory laparotomy with midline abdominal incision Exclusion Criteria: History of substance abuse History of chronic pain syndrome Daily opioid use for more than 1 month Patients considered to have chorioamnionitis at the time of cesarean surgery as determined by the attending physician Prior abdominal surgery involving mesh or placement of an ostomy site as this may disrupt the plane in which the anesthetic may spread Allergy to local anesthetics History of cardiac arrhythmias or cardiac abnormalities History of seizure disorder Liver disease