The Southern Cross Block (SCB): A Technique for Intraoperative Analgesia Post Mastectomy

Authors List

Summer Hassan, Middlemore Hospital, Auckland, New Zealand Claudia Paterson, Middlemore Hospital, Auckland, New Zealand Rana Alsadat, Middlemore Hospital, Auckland, New Zealand Garth Poole, Middlemore Hospital, Auckland, New Zealand

Introduction: Mastectomy is a life-altering physical and psychological event for any patient. Suboptimal management of immediate postoperative pain significantly increases the risk of post-mastectomy pain syndrome. PECs II block is a popular regional analgesic technique expected to anesthetize the lateral chest wall. We propose a surgeon-delivered modification to the PECs II block to improve the quality of recovery.


  • To develop a reproducible, efficient, and safe intraoperative field block
  • To prospectively assess the efficacy of the block by pain scores and opiate consumption

Methods:  The SCB was performed on 96 consecutive patients undergoing mastectomy by a single surgeon from 2020 to 2021. The block consisted of 40 ml of bupivacaine delivered under direct vision to five areas: pectoralis major, pectoralis minor, the interpectoral groove, lateral intercostal nerves with the nerve to serratus anterior, and the medial cutaneous nerves. Patients were assessed utilising a visual analogue pain scale from 0-10 for both movement and at rest at 1,3,6,12 and 24 hours. Additional analgesia was freely given and the total requirements were obtained from patient notes.

Results: The median pain score at rest and with movement at one hour was zero out of 10. The median pain score at three hours at rest and movement were 1 and 2 respectively. Only 28.1% of the patients required second-line analgesic in the first 24h with average commencement at 4.8 hours. Total opioid consumption was minimal, averaging 13.75mg of Oxynorm and Oxycodone, 13.84mg of Sevredol, and 22.5mg of Morphine.  Only 12.5% of patients required a short course of opioids on discharge and none returned to theatre or required readmission secondary to pain.

The SCB is a simple and effective technique to minimise post-mastectomy pain.

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