TAP Block With Lidocaine and Ropivacaine 0.2% (0.4 ml/kg/Side) for Pain and Opioid Reduction After Hysterectomy

Hysterectomy is a common gynecological surgical procedure involving the removal of the uterus. The procedure may be total or subtotal, and is frequently associated with moderate to severe postoperative pain. Effective management of this pain is crucial and is typically achieved through multimodal analgesia. This approach includes regional nerve blocks, systemic analgesics (oral and intravenous), and adjunctive therapies (physical or psychological), resulting in reduced opioid requirements, minimized side effects, and shorter hospital stays.

The transversus abdominis plane (TAP) block is a regional anesthesia technique involving the injection of a local anesthetic between the transversus abdominis and internal oblique muscles. This targets the thoracolumbar nerves (T6-L1) and provides effective analgesia for the anterior abdominal wall. When performed under ultrasound guidance following abdominal surgery, the TAP block has demonstrated benefits including decreased incisional pain, reduced opioid consumption, and improved postoperative mobilization.

This is a prospective, randomized, comparative clinical trial conducted within the Department of Obstetrics and Gynecology at Mureș County Emergency Clinical Hospital. The study period extends from January 2024 to December 2025 or until the target sample size is reached. All anesthetic and surgical interventions utilized are within standard clinical practice; no experimental drugs or procedures are employed.

The study compares two multimodal analgesia protocols to identify the most effective and satisfactory method of postoperative pain management. All participants will provide written informed consent prior to enrollment.

Participants will be randomly allocated into two groups using a computer-generated randomization application on the day of surgery. The anesthesiologist performing the TAP block will be the only staff member aware of group allocation.

To maintain blinding, all participants will leave the operating room with bilateral lateral abdominal dressings, regardless of group assignment. Postoperative evaluators will be blinded to group allocation.

The transversus abdominis plane (TAP) block will be performed under ultrasound guidance using a Sonosite ultrasound system equipped with a linear probe (6-15 MHz). The block will be executed after induction of general anesthesia, utilizing the lateral approach.

The procedure begins by positioning the ultrasound probe at the level of the umbilicus, oriented transversely to identify the rectus abdominis muscle. The probe is then moved laterally and slightly posteriorly to visualize the three muscle layers of the lateral abdominal wall in cross-section: External oblique, Internal oblique, Transversus abdominis.

The final probe position will be between the iliac crest and the costal margin, where the muscle layers are clearly visualized. Under direct ultrasound visualization, the needle (Stimuplex Ultra 360, 20G × 6, 30° bevel, 100-150 mm) is inserted in-plane, from medial to lateral, puncturing the skin above the probe and advancing through the tissue under the ultrasound beam.

The needle is advanced until it reaches the fascial plane between the internal oblique and transversus abdominis muscles. Correct placement is confirmed by the appearance of the "unzipping" or hydro-dissection effect upon injection of a small volume of local anesthetic, indicating separation of the fascial layers.

The local anesthetic solution is then injected in increments of 5 ml per side, with aspiration performed after each increment to exclude intravascular needle placement.

The entire TAP block procedure is conducted under strict aseptic conditions, including:

• Skin disinfection with Braunol iodine solution
• Use of sterile gloves
• Use of a sterile ultrasound probe cover
• Sterile handling of all equipment and medications Preoperative data collected will include age, weight, height, body mass index (BMI), ASA score, comorbidities, gynecologic diagnosis, and baseline Quality of Recovery score (QoR-15).

Intraoperative data will include: time of anesthesia induction, time of TAP block (if applicable), time of surgical incision, total surgery duration, opioid consumption, heart rate and blood pressure.

Intraoperative pain will be defined as a ≥20% increase in heart rate and/or blood pressure compared to baseline values recorded one day prior to surgery.

Postoperative assessments will include:

• Pain intensity at 0, 1, 4, 6, and 24 hours (at rest and during movement)
• Numeric Rating Scale (0-10)
• Patient satisfaction score at 24 hours
• QoR-15 score at 48 hours Data will be recorded using standardized intraoperative and postoperative forms. The intraoperative form will be completed by the anesthesiologist performing the surgery. The postoperative form will be completed by a blinded evaluator (resident or specialist from another unit). All data will be entered into Microsoft Excel and analyzed using GraphPad Prism.

Results will be statistically analyzed and interpreted to identify differences in pain control, opioid consumption, recovery, and patient satisfaction between the two groups. Conclusions will guide the development of updated institutional pain management protocols for hysterectomy.