• Acute postoperative pain at rest [ Time Frame: 24 hours postoperatively ]
  Following breast surgery, measured as an area under the curve (AUC) of rest pain scores VAS scale where 0 corresponds to no pain, and 10 corresponds to worst pain imaginable
• Quality of postoperative recovery (QoR 15) [ Time Frame: 24 hours post-surgery ]
  Quality of recovery at 24 hours: questionnaire (0-10, where 0 = none of the time [poor] and 10 = all of the time [excellent])

• Postoperative pain scores [ Time Frame: 0, 6, 12, 18, 24 and 48 hours post-operatively ]
  VAS scale where 0 corresponds to no pain, and 10 corresponds to worst pain imaginable
• Intraoperative opioid consumption [ Time Frame: During the procedure ]
  Cumulative oral morphine equivalent after surgery
• Postoperative opioid consumption [ Time Frame: 12,24,48 hours, 7 days postoperative ]
  Cumulative oral morphine equivalent after surgery
• Duration of phase I (PACU) and phase II (surgical day care, SDC) stay [ Time Frame: From end of surgical procedure to 24 hours after surgery ]
  How fast is the recovery is-expressed in minutes
• Opioid-related side effects [ Time Frame: End of surgical procedure to 48 hours after surgery ]
  Risk of opioid-related side effects(nausea, vomiting, pruritis)
• Persistent post surgical pain DN4 screening tool [ Time Frame: 3 months post operatively ]
  Satisfaction with pain management. Is prescribed pain medication enough?
• Block-related complications [ Time Frame: End of surgical procedure to 48 hours after surgery ]
  bruising at injection site, numbness over lateral chest, weakness of shoulder or arm, pain/swelling at injection site

• Sensory and motor block onset assesment-pinprick sensation test [ Time Frame: End of surgical procedure until 24 hours post-op ]
  Extent of dermatomal sensory block in the nerves involved will be performed
• Mean opioid analgesic consumption [ Time Frame: 24 hours postoperative ]
  Cumulative oral morphine equivalent after surgery
• Time to first analgesic request [ Time Frame: 24 hours postoperative ]
  The time when first patient need to take analgesic
• Opioid-related side effects [ Time Frame: End of surgical procedure to 7 days following surgery ]
  Risk of opioid-related side effects(nausea, vomiting, pruritis)
• Block-related complications [ Time Frame: End of surgical procedure to 7 days following surgery ]
  Presence/absence of block-related side effects such as bruising, infection, systemic toxicity, persistent numbness or shoulder weakness
• Quality of recovery at 24 hours: questionnaire (0-10, where 0 = none of the time [poor] and 10 = all of the time [excellent]) [ Time Frame: Discharge from hospital until 24 hours post-op ]
  Completion of questionnaire (QoR) done by patient
• Persistent post surgical pain [ Time Frame: 24 hours postoperative ]
  Satisfaction with pain management. Is prescribed pain medication enough?
• Risk of chronic pain [ Time Frame: 3 months postoperatively. ]
  Simple question requiring a yes or no response. Tingling, numbness, pain.

The ultrasound-guided erector spinae plane (ESP) block has been recently described for the successful management of thoracic neuropathic pain. The erector spinae muscle is formed by the spinalis, longissimus thoracis, and iliocostalis muscles that run vertically in the back. The ESP block is performed by depositing the local anaesthetic in the fascial plane, deep to the erector spinae muscle, at the tip of the transverse process of the vertebra. Indirect access to the paravertebral space is gained providing analgesia without the risk of needle injury to structures in close proximity. Cadaveric studies have shown both ventral and dorsal rami of thoracic spinal nerves are affected when local anaesthetic is injected deep to the erector spinae muscle. The erector spinae muscle extends along the thoracolumbar spine allowing extensive cranio-caudal spread. The ventral ramus (intercostal nerve) is divided into the anterior and lateral branches. Its terminal branches provide the sensory innervation of the entire anterolateral wall. The dorsal ramus is divided into 2 terminal branches and it gives the sensory innervation to the posterior wall. Anterior spread of the local anaesthetic to the paravertebral space through the costotransverse foramina and the intertransverse complex provides both visceral and somatic analgesia.

While recent evidence supports statistically significant reductions in pain and opioid consumption among patients who receive an ESP block compared to systemic analgesia alone, the clinical significance of these differences are questionable the effect of ESP block on the patients' quality of recovery following ambulatory breast cancer surgery remains unclear.

Therefore, our objective is to determine whether or not the addition of an ESP block provides both superior analgesia and quality of recovery in patients undergoing ambulatory breast cancer surgery compared to systemic analgesia alone. We hypothesis that patients who received a preoperative ESP block will afford superior postoperative analgesia and improve the quality of recovery over the first 24 hours following surgery compared to those who receive a sham block for their ambulatory breast cancer surgery.

• Breast Cancer
• Nerve Block
• Regional Anesthesia
• Neuromuscular Blockade

• Procedure: Erector spinae plane block
  80mm 22G block needle will be inserted using an in-plane cranial to caudad approach, the needle will be advanced to target the interfascial plane deep to the erector spinae muscle at the T2 transverse process. Once the needle tip is in the correct position, 20 ml of the local anaesthetic (ropivacaine 0.5% with 1:400,000 epinephrine) will be administered slowly in 5 ml aliquots under frequent aspiration and correct spread in the interfascial plane will be observed.
• Procedure: Placebo Block
  Patients randomised to the Control group will then receive a sham subcutaneous injection of 0.5ml normal saline injected at the same site as the ESP block under ultrasound guidance to stimulate a real block procedure.

• Placebo Comparator: Control Group
  Patients randomised to the Control group will then receive a sham subcutaneous injection of 0.5ml normal saline injected at the same site as the ESP block (see above) under ultrasound guidance to stimulate a real block procedure.
  Intervention: Procedure: Placebo Block
• Experimental: Erector spinae plane (ESP) block group
  Local anaesthetic infiltration utilising 1% lidocaine will occur, and an 80mm 22G block needle will be inserted using an in-plane cranial to caudad approach, the needle will be advanced to target the interfascial plane deep to the erector spinae muscle at the T2 transverse process. Once the needle tip is in the correct position, 20 ml of the local anaesthetic (ropivacaine 0.5% with 1:400,000 epinephrine) will be administered slowly in 5 ml aliquots under frequent aspiration and correct spread in the interfascial plane will be observed.
  Intervention: Procedure: Erector spinae plane block

• Blanco R, Parras T, McDonnell JG, Prats-Galino A. Serratus plane block: a novel ultrasound-guided thoracic wall nerve block. Anaesthesia. 2013 Nov;68(11):1107-13. doi: 10.1111/anae.12344. Epub 2013 Aug 7.
• Mazzinari G, Rovira L, Casasempere A, Ortega J, Cort L, Esparza-Miñana JM, Belaouchi M. Interfascial block at the serratus muscle plane versus conventional analgesia in breast surgery: a randomized controlled trial. Reg Anesth Pain Med. 2019 Jan;44(1):52-58. doi: 10.1136/rapm-2018-000004.
• Forero M, Adhikary SD, Lopez H, Tsui C, Chin KJ. The Erector Spinae Plane Block: A Novel Analgesic Technique in Thoracic Neuropathic Pain. Reg Anesth Pain Med. 2016 Sep-Oct;41(5):621-7. doi: 10.1097/AAP.0000000000000451.
• Gürkan Y, Aksu C, Kuş A, Yörükoğlu UH, Kılıç CT. Ultrasound guided erector spinae plane block reduces postoperative opioid consumption following breast surgery: A randomized controlled study. J Clin Anesth. 2018 Nov;50:65-68. doi: 10.1016/j.jclinane.2018.06.033. Epub 2018 Jul 2.

Inclusion Criteria:

• ASA classification: I-III
• BMI < 35 kg/m2
• Day surgery procedure

Exclusion Criteria:

• Prior ipsilateral breast surgery, excluding lumpectomy
• Pre-existing neurological deficit or peripheral neuropathy involving the ipsilateral chest
• Severe, poorly controlled cardiac conditions, significant arrhythmias, severe valvular heart diseases
• Severe, poorly controlled respiratory conditions (severe COPD, severe interstitial lung disease, severe / poorly controlled asthma)
• Contraindication to regional anaesthesia (e.g. bleeding diathesis, coagulopathy, sepsis, infection at the site of potential needle puncture on the posterior chest)
• Patient refusal
• Chronic pain disorder
• Chronic opioid use (≥30 mg oxycodone / day)
• Contraindication (or allergy) to a component of multi-modal analgesia protocol
• Allergy to amide local anaesthetics used in nerve blocks
• Contraindications to any of the components of the standardized general anaesthesia
• Significant psychiatric disorder that would preclude objective study assessment
• Pregnancy/ women with nursing infants
• Unable to provide informed consent