Overview

This prospective, randomized, triple-blind, placebo-controlled clinical trial will investigate the effectiveness of the intertransverse process block (ITPB) for postoperative analgesia in patients undergoing elective thoracotomy with unilateral lobectomy. The study will be conducted at a single tertiary center in accordance with the principles of the Declaration of Helsinki, and written informed consent will be obtained from all participants.

Patients will be randomized in a 1:1 ratio to receive either ultrasound-guided ITPB with 0.5% bupivacaine or placebo (normal saline) prepared in identical syringes to ensure allocation concealment. The block will be performed by an experienced anesthesiologist immediately after surgery and before emergence from anesthesia. Both groups will receive standardized general anesthesia, multimodal perioperative analgesia, and postoperative intravenous morphine patient-controlled analgesia (PCA).

The trial aims to evaluate the analgesic efficacy and opioid-sparing effect of ITPB while maintaining safety and adherence to routine clinical practice. Outcomes will include postoperative pain scores, opioid consumption, rescue analgesia requirement, and adverse events.

Eligibility

Inclusion Criteria:

• Provision of written informed consent

Age between 18 and 85 years

ASA Physical Status classification I-III

Elective thoracotomy with planned unilateral lobectomy

Anticipated hospital stay of at least one night

Expected requirement for parenteral opioid analgesia for at least 24 hours postoperatively

Ability to operate an intravenous patient-controlled analgesia (PCA) device

Exclusion Criteria:

• Patients undergoing emergency surgery

Presence of infection or open wound at the injection site

Coagulopathy

Hepatic or renal failure

Patients undergoing reoperation

Patients with missing or incomplete data

Pregnancy or lactation

Tracheal malformation or tracheostomy

Chronic opioid use (≥30 days within the last 3 months, ≥15 mg/day morphine equivalent)

Patients exceeding the maximum safe local anesthetic dose based on weight (2.5 mg/kg, max 150 mg)

Patients who refuse data privacy consent will be excluded from the study