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. US-guided serratus anterior plane (SAP) block provides effective analgesia in anterior, posterior and lateral dermatomes of thorax. It has been reported that SAP block provides effective postoperative pain management following thoracotomy, breast surgery and VATS. There is no clinical randomized study evaluating the efficacy of ESP block and SAP block following VATS in the literature.

Video assisted thoracic surgery (VATS) has recently been evaluated as the standard surgical procedure for lung surgery. The advantages of VATS procedures compared with open thoracotomy are rapid recovery, short hospital stay and low complication risk. 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. The ESP block contains a local anesthetic injection into the deep fascia of erector spinae. This area is away from the pleural and neurological structures and thus minimizes the risk of complications due to injury. 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. Cadaveric studies have shown that the injection spreads to the ventral and dorsal roots of the spinal nerves and creates sensory blockade in both posterior and anterolateral thorax. In the literature, it has been reported that ESP block provides effective analgesia after open heart surgery, breast surgery and ventral hernia repair in randomized controlled studies about ESP block efficiency for postoperative analgesia management. In some case series and case reports it has been reported that ESP block provides effective analgesia after thoracotomy and VATS. Furthermore, it has been reported that it provides effective analgesia in chronic and persistant pain syndromes of thorax.

US-guided serratus anterior plane (SAP) block is an interfascial plane block and was described by Blanco in 2013. A local anesthetic solution is performed into the fascial plane of serratus anterior muscle. It is easy to perform and has low complication rate because it is far away from the important neurological and vascular structures. The serratus anterior muscle may be seen easily with US guidance in the mid-axillary line. It provides effective analgesia in anterior, posterior and lateral dermatomes of thorax. It has been reported that SAP block provides effective postoperative pain management following thoracotomy, breast surgery and VATS. There is no clinical randomized study evaluating the efficacy of ESP block and SAP block following VATS in the literature.

The aim of this study is to compare US-guided ESP block and SAP block for postoperative analgesia management after VATS. The primary aim is to compare perioperative and postoperative opioid consumption and the secondary aim is to evaluate postoperative pain scores (VAS), adverse effects related with opioids (allergic reaction, nausea, vomiting) and complications due to blocks (pneumothorax, hematoma).

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) classification I-II
• Scheduled for VATS under general anesthesia

Exclusion Criteria:

• Bleeding diathesis
• Receiving anticoagulant treatment
• Known local anesthetics and opioid allergy
• Infection of the skin at the site of the needle puncture
• Pregnancy or lactation
• Patients who do not accept the procedure

Individual participant data (IPD) will not be shared

Outcomes Assessor and participant will be blinded to the study