Video assisted thoracic surgery (VATS) has recently been evaluated as the standard surgical procedure for lung surgery. Although VATS is less painful than thoracotomy, patients may feel severe pain during the first hours at postoperative period. Analgesia management is very important for these patients in postoperative period since insufficient analgesia can cause pulmonary complications such as atelectasis, pneumonia and increased oxygen consumption. The ultrasound (US) guided erector spina plane (ESP) block is a novel interfacial plan block defined by Forero et al. at 2016. ESP block provides thoracic analgesia at T5 level and abdominal analgesia at T7-9 level. Visualization of sonoanatomy with US is easy, and the spread of local anesthesic agents can be easily seen under the erector spinae muscle. Thus, analgesia occurs in several dermatomes with cephalad-caudad way. In the literature, there is not still any randomized study evaluating ESP block efficiency for postoperative analgesia management after VATS. The aim of this study is to evaluate US-guided ESP block for postoperative analgesia management after VATS.

Postoperative pain after thoracic surgery which is attributed to muscle incision, rib retraction, and intercostal nerve damage may be severe such a degree that it may cause pulmonary complications such as atelectasis, pneumonia and increased oxygen consumption. Because video assisted thoracic surgery (VATS) has some advantages over open thoracotomy such as reduced pain, shoulder dysfunction, early pulmonary impairment, rapid recovery, short hospital stay and low complication risk, it has recently been evaluated as the standard surgical procedure for lung surgery. Although VATS is a less painful procedure than open thoracotomy, patients may still feel severe pain during the first hours at postoperative period. As thoracic epidural analgesia (TEA) is the gold standard analgesic technique after thoracotomy, it is also being used for analgesia management following VATS. Hence TEA has some difficulties in administration and side effects, minimally invasive analgesic techniques are supported for pain management in patients who underwent VATS. The gold standard minimal invasive analgesic technique for VATS is still be questioned. Thoracic paravertebral block (TPVB) has been evaluated as the first step regional analgesia technique after VATS. However, its administration is difficult because of its anatomical proximity to important structures such as the pleura and central neuro-axial system. Therefore it may cause complications such as pneumothorax and neuro-axial injury. The ultrasound (US) guided erector spina plane block (ESPB) - a novel interfacial plan block defined by Forero et al. in 2016 - has the advantage of being away from the pleural and neurological structures, thus the risk of complications is lower. In the literature, case reports about the analgesic effect of ESPB after thoracotomy and VATS has been increasing. However there is no randomized study for VATS yet. In this study, investigators aimed to evaluate the efficacy of US-guided ESPB for postoperative analgesia management following VATS.

Inclusion Criteria:

• Clinical diagnosis of primary lung carcinoma
• Must be undergoing VATS lobectomy under general anesthesia
• Must be in American Society of Anesthesiologists (ASA) classification I-II status

Exclusion Criteria:

• History of bleeding diathesis,
• History of receiving anticoagulant treatment,
• History of local anesthetics or opioid allergy,
• Skin infection at the site of the needle puncture,
• Presence of pregnancy or lactation, and
• Patients who did not accept the procedure

individual participant data (IPD) will not be shared

Postoperative pain assessment was performed by a anesthetists blinded to the procedure.