Comparison of the Effect of Preoperative and Postoperative Erector Spina Plan Block and Paravertebral Block on Postoperative Pain in Video Assisted Thoracic Surgery (VATS)

Pain after thoracic surgery is common and usually severe due to factors such as surgical incisions, damage to the lung tissue and ribs, and irritation of the pleura and intercostal nerves by the chest tube. Thoracotomy is one of the most painful surgical operations and the incidence of chronic pain has been reported to be approximately 65% in most studies. Video-assisted thoracic surgery (VATS) has become more common in recent years. Compared with open thoracotomy, VATS reduces postoperative pain, morbidity and length of hospital stay, which is associated with a smaller extent of tissue trauma. However, VATS still causes moderate to severe acute postoperative pain and chronic pain with an incidence reported in the range of 25-35%.

Accelerated rehabilitation is important in thoracic surgery. Postoperative outcomes are affected by the patient's ability to get out of bed and participate in physical respiratory therapy exercises. Inadequate analgesia is also directly related with postoperative pulmonary functions. Pain may lead to atelectasis, hypoxaemia and pneumonia as a result of ineffective cough and thus inadequate sputum expulsion.

Pain management after VATS is important because it may reduce postoperative complications. Systemic analgesic methods using intravenous (iv) drugs such as lidocaine, nonsteroidal anti-inflammatory drugs, steroids, alpha2-adrenergic agonists or N-methyl-D-aspartate (NMDA) antagonists and thoracic epidural analgesia, The multimodal analgesia approach in which regional analgesia methods such as paravertebral block, erector spina plan (ESP) block, and serratus anterior plan block are combined is an approach with proven efficacy in recent studies and guidelines. Regional analgesia has the potential to reduce postoperative acute pain and chronic pain and to increase early postoperative recovery.

Although thoracic epidural anaesthesia (TEA) is considered the gold standard for the treatment of postoperative pain in thoracic surgery, the presence of possible side effects such as dura perforation, nerve damage, epidural bleeding, risk of hypotension and urinary retention has shown that VATS may require less invasive analgesia. Thoracic paravertebral block (TPVB) provides unilateral thoracic analgesia comparable to TEA. In addition, it is not only less invasive than TEA, but also can maintain haemodynamic stability and carries a lower risk of complications. According to the Enhanced Recovery After Surgery (ERAS) guidelines and the Procedure-specific postoperative pain Management (PROSPECT) group, TPVB is recommended as the primary method of regional analgesia for thoracic surgery.

Paravertebral local anaesthetic may spread to multiple levels into the epidural and intercostal spaces, blocking the spinal nerve and sympathetics, resulting in segmental block and ipsilateral sympathectomy. Major risks or complications of PVB include pneumothorax, hypotension due to bilateral PVBs, dural puncture and possible risks associated with epidural injections, including epidural abscess, epidural haematoma. In recent years, there has been increasing interest in fascial plane blocks, which involve spreading large amounts of local anaesthetics into the fascial planes through which nerves pass or communicate with other areas containing the nerves of interest. The erector spinae plane block is the most widely investigated fascial plane block that is most suitable for thoracic surgery. It is technically easier to perform and theoretically has lower risks of serious adverse events associated with TEA and PVB, including epidural haematoma or abscess or pneumothorax, and is less likely to cause sympathectomy or hypotension. ESPB targets the facial plane between the erector spinae muscles and the posterior border of the transverse processes, blocking the dorsal branches of the spinal nerves and potentially spreading anteriorly into the adjacent paravertebral and epidural spaces, blocking the ventral rami and sympathetic chain.