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

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.

Inclusion criteria

• ASA physical status I-II-III
• Patients scheduled for elective total abdominal hysterectomy under general anesthesia and who have received either a preoperative rectus sheath block or a transversus abdominis plane block
• Aged 18-70 years
• Patients who agree to participate in the study and provide written informed consent

Exclusion criteria

• Patients who refuse to participate
• Patients who have not received any regional anesthesia technique
• ASA physical status IV
• Patients in whom unilateral or bilateral sensory spread is not observed following the bilaterally applied regional anesthesia technique
• Patients who are uncooperative or have cognitive impairment or dementia
• Patients with psychiatric disorders such as depression, mania, or schizophrenia, or those using antipsychotic medications for more than 4 weeks