This study evaluates the analgesic effects of ultrasound-guided regional techniques, Thoracic Paravertebral Block (TPVB), Erector Spinae Plane Block (ESPB) and Serratus Anterior Plane Block(SAPB) by comparing postoperative total morphine consumption, first analgesic requirement time, and postoperative pain scores ( FLACC/NRS), postoperative chronic pain in 3rd month in pediatric patients undergoing thoracic surgery. The investigators also aim to observe the side effects of these techniques such as nausea, vomiting, bradycardia, hypotension, respiratory depression

Thoracic surgery is one of the most common causes of postoperative severe pain due to the damage to intercostal nerves, irritation of the pleura and rib retraction. Effective analgesia provides patient comfort and enables early mobilization, reducing complications such as pneumonia, respiratory failure, hypoxia, and hypercapnia. In pediatric patients, nonsteroid anti-inflammatory drugs, opioids and regional analgesia techniques can be used for multimodal analgesia. Several side effects of opiates such as respiratory depression, nausea, vomiting, itching, addiction, and sedation effect patients' comfort and delay discharge. Nowadays US-guided truncal block techniques such as thoracic paravertebral block (TPVB) become popular. TPVB provide the somatosensorial and visceral block with an injection of the local anaesthetic agent into the paravertebral space. Existing evidence demonstrates the non inferiority of TPVB compared with TEA for postoperative analgesia and TPVB can reduce side effects. Erector Spina Plan Block (ESPB) was first described in 2016 as an ultrasound-guided truncal block for thoracic neuropathic pain and now ESPB uses for many different thoracics and abdominal surgeries for postoperative analgesia. Several studies have shown that ESPB can provide adequate analgesia in postoperative thoracic pain. ESPB is gaining popularity because its application is easy and safe compared with TPVB. Another new US-guided regional anaesthetic block technique, the serratus anterior plane block (SAPB), targets the plane above or below the serratus anterior muscle in the midaxillary line and provides analgesia to a hemithorax by blocking the lateral branches of the intercostal nerves, thoracicus longus and thoracodorsal nerves. The SAP block provides analgesia to the 2nd and 9th thoracic dermatomes. The SAP block is safe, and easy to perform, owing to its easy-to-learn technique and distinct bony landmarks. So, it can be an attractive alternative for pain relief after thoracic surgery.

In this study, Investigators aim to compare the efficacy of these three techniques in pediatric patients. The primary hypothesis is the analgesic efficacy of SAPB will be equivalent to TPVB and RSPB. The primer outcome is postoperative total narcotic analgesic consumption in 24 hours. The seconder outcomes are; time of postoperative first analgesic requirement, postoperative pain scores (FLACC - NRS) in 0.-15.-30.-45.minutes and 1.-2.-6.-12.-24.-48. hours, chronic thoracic pain 3 months after surgery, intraoperative additional fentanyl requirement, postoperative additional paracetamol requirement, intraoperative hemodynamic parameters, first mobilization time, side effects, technical complications, and the satisfaction of patient-surgeon.

Inclusion Criteria:

1-14 age patients undergoing thoracic surgery, ASA 1-2-3, Patients without chronic opioid use

Exclusion Criteria:

Denial of patient or parents, Infection of the local anaesthetic area, Infection of the central nervous system, Coagulopathy, Brain tumours, Known allergy against local anaesthetics.