The purpose of this clinical trial is to evaluate whether two different analgesic techniques - ultrasound-guided Transversalis Fascia Plane Block (TFPB) and surgical wound infiltration - can improve postoperative pain control in adult patients undergoing open inguinal hernia repair.

The key questions that this study aims to answer are:

Does TFPB reduce total intravenous opioid consumption within the first 24 postoperative hours compared with wound infiltration?

Does TFPB improve postoperative pain scores at rest and during movement compared with wound infiltration?

Does TFPB improve patient satisfaction, reduce the need for rescue analgesics, and enhance overall postoperative recovery quality?

If there is a comparison group:

The investigators will compare the effects of TFPB with wound infiltration to determine whether either technique provides superior postoperative analgesia and reduces opioid requirements.

Participants will be asked to:

Undergo open inguinal hernia repair under spinal anesthesia.

Be randomly assigned to one of two groups:

TFPB Group: Receive an ultrasound-guided transversalis fascia plane block with local anesthetic.

Wound Infiltration Group: Receive local anesthetic infiltration performed by the surgeon along the incision line.

Postoperatively:

Report pain scores at defined intervals.

Receive standardized IV analgesia with documentation of opioid consumption.

Allow assessment of rescue analgesic requirement.

Be monitored for adverse events and recovery outcomes.

worldwide. Inadequate analgesia in the early postoperative period may lead to delayed mobilization, prolonged hospital stay, and increased opioid consumption. Accordingly, current international guidelines recommend multimodal analgesia strategies and the use of regional anesthesia techniques when appropriate (1). Surgical wound infiltration is a frequently used component of multimodal analgesia in groin surgery; however, its effectiveness may vary depending on the timing of administration, technique, and the homogeneity of local anesthetic spread, and its duration of action is often limited. Recent clinical series continue to report significant postoperative pain and notable opioid requirements following primary unilateral open repair (1).

In recent years, ultrasound-guided fascial plane blocks have gained increasing attention due to their more predictable spread and potential to provide longer-lasting analgesia (2). The TFPB block is a truncal block achieved by injecting local anesthetic between the transversus abdominis muscle and the transversalis fascia, thereby targeting the T12-L1 spinal nerves. This anatomical distribution provides a strong physiological rationale for its use in inguinal region surgery (3).

Several studies have demonstrated that the TFPB can reduce postoperative pain scores and rescue analgesic requirements in pediatric herniotomy and adult groin surgeries (4). However, randomized controlled trials directly comparing the TFPB with surgical wound infiltration in open inguinal hernia repair remain limited. Existing evidence partly stems from comparisons with other fascial plane blocks (e.g., Quadratus Lumborum [QL], Transversus Abdominis Plane [TAP] block or from studies in different types of groin surgery, such as subinguinal varicocelectomy (5-7). Therefore, whether the TFPB provides a clinically meaningful advantage over wound infiltration in open inguinal hernia repair is a clinically relevant question that remains to be definitively answered.

This study aims to compare the contribution of the TFPB and surgical wound infiltration to postoperative analgesia in patients undergoing elective unilateral open inguinal hernia repair. The primary hypothesis is that TFPB will reduce cumulative rescue opioid consumption during the first 24 postoperative hours compared with wound infiltration. The secondary hypotheses are that TFPB will decrease postoperative pain scores, prolong the time to first rescue analgesia, and improve patient satisfaction without increasing the incidence of postoperative nausea and vomiting (PONV) or other adverse events.

articipants will be randomized into one of two intervention arms.

In the TFPB group, an ultrasound-guided transversalis fascia plane block will be performed in the postoperative period using a standardized volume and concentration of local anesthetic.

In the Wound Infiltration group, local anesthetic will be infiltrated by the surgeon into the relevant layers of the incision site at the end of the surgery.

All patients will receive a standardized spinal anesthesia protocol and a uniform postoperative analgesia regimen. Postoperative pain scores and opioid consumption will be recorded at predefined time intervals. The investigators responsible for postoperative assessments will remain blinded to group allocation throughout the study.

Primary outcome measure:

Total opioid consumption during the first 24 postoperative hours.

Secondary outcome measures:

NRS pain scores at rest and during coughing, the number of patients requiring rescue analgesia, the incidence of postoperative nausea and vomiting, block-related complications, and overall patient satisfaction.

Inclusion Criteria:

• Age ≥ 18 years
• Scheduled for elective unilateral open inguinal hernia repair
• Planned anesthesia: spinal anesthesia
• American Society of Anesthesiologists (ASA) physical status I-II
• Able to understand the study procedures and provide written informed consent

Exclusion Criteria:

• Body mass index (BMI) > 35 kg/m²
• Known hypersensitivity to local anesthetics used in the study (e.g., bupivacaine) or to analgesic medications
• Coagulopathy
• Infection or hematoma at the planned block site
• Significant systemic disease (such as chronic kidney disease, hepatic failure, chronic obstructive pulmonary disease, etc.)
• History of chronic pain or long-term analgesic use
• Inability to use the patient-controlled analgesia system
• Presence of psychiatric disorders
• Refusal to participate in the study.
• Cases with a surgical duration shorter than 30 minutes or longer than 180 minutes were excluded.

ndividual participant data will not be shared.