During VATS (Video assisted thoracic surgery) small incisions are made in the patient's chest through which a camera and instruments are inserted to allow a lung operation to be performed. Often patients experience a substantial amount of pain and difficult recovery after this type of operation. Anaesthesiologists sometimes use "Regional Anaesthesia" to minimise the pain and help patient recovery after the operation. This involves injecting local anaesthesia into the nerves around the chest wall to effectively numb that part of the chest. There is a variety of different locations on the chest wall where the local anaesthetic can be deposited and no study has measured whether one technique is better than the other in terms of improving patients' recovery experience. Our study compares two new techniques for Regional Anaesthesia after this type of surgery. Participants will be randomly assigned (like tossing a coin) to receive either a SAP (Serratus Anterior Plane) or ESP (Erector Spinae Plane) Block. Both techniques are described within last five years, but have never been compared for chest surgery

The Serratus Anterior Plane (SAP) Block has been claimed to be a safer, technically less demanding alternative to paravertebral block and thoracic epidural in the management of post operative VATS associated pain . Recently, another new block, the Erector Spinae Block (ESP Block) has been described for use in thoracic wall surgery. It has also been claimed to be easier to perform than these more traditional methods of regional anaesthesia. No study to date has compared ESP to SAP blocks in terms of efficacy of post operative analgesia after VATS surgery. Furthermore, patient-centres outcome studies now demand that researchers evaluate more than acute pain in the early postoperative period: A 15-parameter Quality of Recovery score (QoR-15) has been recommended as the optimum tool to evaluate overall patient-centres measures of recovery after surgery, including pain. This study will test the hypothesis that patients receiving ESP Block have higher QoR-15 scores and better post operative analgesia in comparison with patients receiving SAP Block after VATS surgery.

Inclusion Criteria:

• Male and Female participants providing written informed consent,
• ASA grade 1- 4,
• aged over 18
• undergoing a VATS procedure under General Anaesthesia

Exclusion Criteria:

• Absence of informed written consent,
• pre existing infection at block site,-
• severe coagulopathy,
• allergy to local anaesthesia,
• pre existing neurological deficit,
• previous history of opiate abuse,
• pre existing chronic pain condition,
• pre-existing dementia [because of need to co-operate in completing QoR-15 score day after surgery].

Blocks will be administered after induction of General Anesthesia so participants will be blinded to which intervention they have had.

Study investigators will not be aware as to what group the participant belongs to when assessing the patient post operative period