Exparel vs. Bupivacaine Hydrochloride vs. Placebo for Transversus Abdominis Plane Blocks During Open Retromuscular Hernia Repair

This will be a double-blind, 3-arm, randomized controlled trial with a treatment 1: treatment 2: control allocation ratio of 1:1:1. Primary outcomes of interest are opioid requirements and pain scores over initial 72 hours of the postoperative period. Opioid requirements will be assessed by measuring the cumulative dose of opioids administered intravenously (infused through a patient-controlled analgesia device as well as the quantity of opioids administered intravenously as rescue, if needed) and the quantity of opioids administered through oral preparations. This will be assessed at time points: while patients are at the post-anesthesia care unit (PACU), at postoperative days 1(24h±4 hours), 2(48h±4 hours), 3(72h±4 hours) and at the date of hospital discharge. The total dose of opioids used at each time point will be recorded and converted into morphine equivalents for standardization and analysis. The cumulative dose of opioids from 0 hours to 72 hours after the operation and for the total hospital length of stay will be recorded. In addition, the dose of opioids administered intra-operatively by the anesthesiologist, time for first oral opioid dose over the first 72 hours (discontinuation of PCA), and the percentage of patients not requiring opioids over the first 72 hours will also be recorded.

Pain scores will be determined using a 100mm visual analog scale (VAS). The VAS is a 100mm horizontal line with two endpoints: 0 (no pain) and 100 (worst imaginable pain). Pain scores will be assessed at baseline during preoperative evaluation, at the PACU, at postoperative days 1(24h±4 hours), 2(48h±4 hours), 3(72h±4 hours), and at the time of hospital discharge.

Additional pain scores will be obtained using the Patient-Reported Outcome Measurement Information System (PROMIS) Pain Intensity 3a survey at baseline and 30-day follow-up. This survey will be completed by patients in person during enrollment and 30-day follow-up. Secondary outcomes of interest include the length of hospital stay and Patient-Reported Quality of Life (PRQOL). Both information is already routinely collected through the Americas Hernia Society Quality Collaborative (AHSQC). Length of hospital stay will be recorded in days. PRQOL will be assessed using the Hernia-Related Quality-of-Life survey (HerQLes). The HerQLes is a 12-item, validated, hernia-specific survey that assesses quality of life through abdominal wall function after ventral hernia repair. HeQLes scores will be assessed at baseline and 30 days after the operation.

All patients will undergo the same operation, under a standard of care protocol. Skin preparation, hair removal, perioperative antibiotics and venous thromboembolism prophylaxis will be performed per Surgical Care Improvement Project protocol guidelines. The procedure will be performed through a midline incision. Upon entering the abdominal cavity, all adhesions between intra-abdominal contents and the anterior abdominal wall are routinely lysed using sharp dissection. When present, hernia contents are reduced back to the cavity. At the end of adhesiolysis, the surgeon will ask the OR nurse to contact the investigational pharmacy via telephone, who will randomize the subject. The investigational pharmacy will be responsible for preparing and dispensing the assigned intervention. The OR nurse will receive the drug from the investigational pharmacy in a standardized bag and will dispense it to the surgeon at the time of the TAP block. Neither the surgeon nor other members of the surgical team will be informed about which of the interventions were assigned to the specific patient. Electronic medical records will contain the information: "Patient was randomized and assigned to receive intervention according to randomization performed by investigational pharmacy." Retromuscular hernia repair is performed initially incising the posterior rectus sheath just lateral to the linea alba. The release will be performed at least 5 cm above and below the fascial defect, and retrorectus dissection is carried out laterally in the direction of the linea semilunaris. If deemed necessary, a posterior component separation will be performed by incising the posterior lamella of the internal oblique, dividing the fibers of the transversus abdominis muscle and dissecting the preperitoneal and retroperitoneal spaces of the lateral abdominal wall laterally.

At the end of the myofascial release, randomization will occur and the assigned intervention drug will be dispensed in syringes to the surgeon who will perform the perform a TAP block under direct visualization. Patients will be randomized using a computer-generated random allocation sequence, by the investigational pharmacy personnel.