Erector Spinae Plane Block for Percutaneous Nephrolithotomy

Percutaneous nephrolithotomy (PCNL) is an effective standard urological procedure for the fragmentation and removal of large renal calculi. Although PCNL is performed as a minimally invasive technique, dilation of the renal capsule and parenchymal tract, as well as peritubular distension caused by the nephrostomy tube, may result in severe postoperative pain. Various analgesic strategies have been described in the literature for postoperative pain management following PCNL. These include systemic opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), and several regional analgesia techniques. However, due to their adverse effect profiles, opioids and NSAIDs are not ideal options, particularly in patients with renal dysfunction. Regional techniques that have been utilized include local infiltration, intercostal nerve blocks, paravertebral blocks, and epidural analgesia. The kidney is primarily innervated between the T10 and L1 segments, whereas the ureter receives innervation from T10 to L2. Based on this anatomical knowledge, unilateral regional blockade between T10 and L2 can provide adequate analgesia for PCNL procedures. Thoracic paravertebral block was previously a commonly preferred technique; however, it may be associated with complications such as intravascular injection, unintended epidural or intrathecal spread, and pneumothorax during its performance. In recent years, the number of reports describing the use of the erector spinae plane block (ESPB) as part of multimodal anesthesia for postoperative analgesia has increased. In ESPB, local anesthetic is injected into the interfascial plane between the transverse process of the vertebra and the erector spinae muscles, and has been reported to spread to multiple paravertebral spaces. ESPB is considered a peri-paravertebral block that can affect both visceral and somatic pain pathways. The aim of this study is to evaluate the effect of ultrasound-guided erector spinae plane block on intraoperative and postoperative opioid consumption, postoperative pain scores, and quality of recovery in patients undergoing percutaneous nephrolithotomy.

Inclusion Criteria: * Age ≥ 18 years. * American Society of Anesthesiologists (ASA) physical status I-II. * Scheduled for elective percutaneous nephrolithotomy under general anesthesia. * Able to understand the study procedures and provide written informed consent. Exclusion Criteria: * Age \< 18 years. * ASA physical status III-IV. * Refusal to participate in the study. * Known allergy or contraindication to local anesthetics (bupivacaine), opioids, or study medications. * Coagulopathy or anticoagulant therapy contraindicating regional block. * Infection at the injection site. * Severe psychiatric or cognitive disorder precluding reliable pain assessment or questionnaire completion.