Comparison of Sensory Block Coverage and Clinical Effectiveness of TAP and Rectus Sheath Blocks in Pfannenstiel Incisions

Overview

Hysterectomy is one of the most common major gynecologic surgeries performed for various indications, and hundreds of thousands of procedures are carried out annually, particularly in developed countries. In total abdominal hysterectomies, the Pfannenstiel incision is frequently preferred due to its advantages in terms of aesthetics, functionality, and postoperative recovery. However, this incision can cause significant postoperative pain because of the extensive cutaneous innervation of the lower abdominal wall. This pain may delay early mobilization and negatively affect patient comfort and satisfaction. As part of multimodal analgesia strategies, regional anesthesia techniques are widely used in such surgeries to reduce opioid consumption and enhance analgesic efficacy. In this context, the Transversus Abdominis Plane (TAP) block and the Rectus Sheath Block (RSB) are among the effective techniques targeting the anterior abdominal wall, and various studies have investigated their spread patterns and clinical outcomes. However, data on the extent to which these blocks provide cutaneous sensory coverage of the Pfannenstiel incision remain limited, and direct comparative mapping studies are scarce in the literature. For patients undergoing hysterectomy, regional anesthesia techniques are commonly applied perioperatively either as a single technique or in combination for pain management, with TAP and RSB being the most frequently used modalities. In addition, patient-controlled analgesia (PCA) devices are routinely employed as a component of multimodal pain management in this population. The aim of this study is to comparatively evaluate the cutaneous sensory block areas produced by the TAP and RSB regional anesthesia techniques, their rates of coverage of the Pfannenstiel incision, and their clinical effectiveness.

Inadequate pain control after hysterectomy is associated with prolonged hospital stay, delayed recovery, decreased quality of life, and reduced patient satisfaction. Therefore, multimodal analgesia strategies that provide high analgesic efficacy with a low side-effect profile are essential in these patients during the postoperative period. Effective postoperative analgesia may also reduce the risk of developing chronic pain after hysterectomy. Although opioids are often routinely used in the postoperative period, their widespread use may lead to adverse effects such as nausea and vomiting, constipation, pruritus, urinary retention, respiratory depression, and, in the long term, an increased risk of misuse. In our clinic, regional anesthesia techniques under ultrasound guidance are routinely administered by experienced anesthesiologists-either as single techniques or in combination-for perioperative pain management in patients undergoing hysterectomy. In addition, patient-controlled analgesia (PCA) devices are used as part of multimodal pain management. This study was designed as an observational study. It aims to comparatively evaluate the cutaneous sensory block areas produced by bilateral Transversus Abdominis Plane (TAP) block and bilateral Rectus Sheath Block (RSB) in patients undergoing elective total abdominal hysterectomy with a Pfannenstiel incision under general anesthesia, focusing on the extent to which these regional anesthesia techniques cover the Pfannenstiel incision and their clinical effectiveness. Among the patients who receive either of these techniques, written informed consent will be obtained, and sensory anesthesia will be evaluated at the 45th minute using the pinprick test. The sensory borders identified during the assessment will be marked on the patient's abdomen, after which an acetate sheet will be placed over the abdomen to transfer the anatomical projection of these borders. Additionally, anterior abdominal reference landmarks specific to each patient (xiphoid process, costal margin, anterior axillary line, iliac crest, inguinal ligament, and symphysis pubis) will be marked on the acetate sheet. Before the surgery begins, the Pfannenstiel incision planned by the surgeon will be drawn on the patient and transferred onto the acetate sheet. Each acetate template will then be digitized, and the percentage of Pfannenstiel incision coverage by the cutaneous sensory block area produced by the regional anesthesia technique will be calculated using ImageJ software. Furthermore, the percentage of the anterior abdominal wall covered by the bilaterally applied regional anesthesia technique will be calculated separately for each patient. Postoperatively, patients' pain scores will be recorded at 1, 3, 6, 12, 18, and 24 hours using the Numerical Rating Scale (NRS), both at rest and during coughing. Total analgesic consumption from the PCA device will also be documented at the same time intervals. At the end of the 24th hour, all patients will be assessed using the Quality of Recovery-15 (QoR-15) questionnaire.