Anesthesia in the News
  • New Practice Advisory on PECS Blocks

    In the first-ever recommendations regarding the efficacy of pectoralis (PECS) blocks developed by any professional anesthesia society, The Society for Ambulatory Anesthesia (SAMBA) has just released the work product of a task force convened to explore the efficacy of this regional analgesic technique commonly used in breast surgery.

    The practice advisory, published April 15 in the journal Annals of Surgical Oncology, compared the efficacy of PECS blocks with systemic analgesia, local infiltration anesthesia, and paravertebral blockade.  The purpose of the advisory is to provide guidance to the ambulatory anesthesia provider in regard to the current scientific evidence supporting the use of PECS blocks for ambulatory breast surgery.

    PECS-1 or PECS-2?

    The use of PECS blocks has increased considerably since the first description of the technique by Blanco in 2011.  The purpose of the original block is to anesthetize the lateral and medial pectoral nerves as they course in between the pectoralis major and minor fascia.  Among patients undergoing breast-conserving surgery, PECS blocks moderately reduce postoperative opioid use, prolong time to analgesic rescue, and decrease postoperative pain scores when compared with systemic analgesics.

    As the popularity of the original block has grown, the original technique of placing local anesthetic between the pectoralis major and minor muscles has been reclassified as PECS-1, and another version of the block, known as the PECS-2, has also seen more widespread use.  This latter technique aims to also anesthetize the upper intercostal nerves by depositing local anesthetic in between the pectoralis minor and serratus anterior muscles.

    Using the Delphi method, task force consensus was achieved on 2 clinical questions that were judged to be most applicable to the current use of regional anesthesia in ambulatory breast surgery:

    • Does PECS-1 and/or -2 blockade provide more effective analgesia for breast conserving surgery than either systemic analgesics or surgeon-provided local infiltration anesthesia?
    • Does PECS-1 and/or -2 blockade provide equivalent analgesia for mastectomy compared with a paravertebral block (PVB)?

    Real-life surgical situations

    These two questions were chosen to explore because (1) lumpectomies and other tissue-conserving breast cancer surgeries are often performed on an outpatient basis; (2) the scientific literature examining the use of PECS blocks for these more limited breast surgeries has increased in recent years; and (3) paravertebral blockade is often considered the gold standard regional anesthetic technique for major breast surgery.  Further, the authors note that they also chose these questions because they reflected commonly encountered circumstances in their own clinical practices as well as situations that could commonly be encountered by anesthesia providers in non-academic settings.

    The PVB option

    In undergoing this comparative technique exercise, the authors note that while “PVB is an effective and well-established technique to provide excellent analgesia and anesthesia for breast surgery, its use in clinical practice (particularly at non-academic centers) may be limited because of its perceived higher degree of technical difficulty and the proximity of the paravertebral space to the spinal canal.”

    Thus, for the anesthesia provider “who desires to perform an evidence-based ultrasound-guided regional anesthetic technique for breast surgery, the PECS blocks are certainly an attractive option.”

    Who examined the evidence?

    The task force was comprised of 8 members of SAMBA’s regional anesthesia committee and 3 breast surgeons.  All anesthesiology provider task force members are practicing anesthesiologists at major university/academic centers who are experts in regional anesthesia and provide anesthesia (including regional anesthesia) for ambulatory surgery as part of their daily practice.  All breast surgeon task force members are practicing surgeons at major academic centers who specialize in breast oncology.

    Scope of review

    The task force’s initial review yielded 185 articles, of which 90 were excluded because they were not randomized controlled trials (RCTs), meta-analyses, observational studies, or retrospective analyses.  Forty-nine of the remaining studies were judged by the task force to be relevant to this practice advisory and were reviewed.

    The strength of the evidence was graded using a classification system similar to that found in the American Society of Anesthesiologists and American Society of Regional Anesthesia and Pain Medicine’s “Practice Advisory for the Prevention, Diagnosis, and Management of Infectious Complications Associated with Neuraxial Techniques.”  All members of the task force were involved in deciding whether a study met the inclusion criteria and assessing potential bias.  During the review process, task force members worked in teams to review studies; type of surgery, sample size, intervention and control groups, bias risk, and primary and secondary outcomes were recorded in a standardized fashion.  Collected data were verified within each team and re-verified by one of the authors.

    Task force conclusion

    Following this analysis of the literature, SAMBA recommends the use of a PECS-1 or -2 blockade in the absence of systemic analgesia (Strength of Recommendation A).  “No evidence currently exists that strongly favors the use of PECS blocks over surgeon-performed local infiltration in this surgical population,” the authors write.

    Further, the task force found that it cannot recommend PECS blocks over surgical infiltration or vice versa (Strength of Recommendation C).  For patients undergoing a mastectomy, a PECS block may provide an opioid-sparing effect similar to that achieved with PVB; SAMBA recommends the use of a PECS block if a patient is unable to receive a PVB (Strength of Recommendation A).

    3 clinical takeaways

    For patients undergoing lumpectomy or breast-conserving surgery, the authors conclude that:

    • Statistically, PECS blocks reduce postoperative opioid consumption, prolong time to analgesic rescue, and decrease postoperative pain scores compared with systemic analgesics. However, the clinical impact of these modest effects is questionable and requires further investigation. Thus, the use of PECS blocks may be of limited value when systemic analgesia is utilized in lumpectomy or breast-conserving surgery.
    • Use of PECS block will likely not result in decreased intraoperative opioids compared with systemic analgesics.
    • Regarding local infiltration analgesia, given the conflicting data, lack of high-quality evidence, and no studies comparing PECs blocks with surgical infiltration in patients undergoing only lumpectomy, the potential advantages of PECS blocks over surgical infiltration or vice versa are unclear.

    The task force’s complete practice advisory, “The Use of Pectoralis Blocks in Breast Surgery: A Practice Advisory and Narrative Review from the Society for Ambulatory Anesthesia (SAMBA),” can be found at

    https://pubmed.ncbi.nlm.nih.gov/35365403/

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