A randomised controlled trial of pectoral nerve‐2 (PECS 2) block vs. serratus plane block for chronic pain after mastectomy

Abstract

Thoracic interfascial plane blocks are effective for post-mastectomy acute analgesia. However, their effects on chronic pain are uncertain. We randomly allocated 80 women equally to pectoral nerve-2 (PECS 2) block or serratus plane block. The pectoral nerve-2 block reduced the rate of moderate or severe chronic pain from 13/ 40 (33%) with the serratus plane block to 4/40 (10%), p = 0.03, adjusted odds ratio (95%CI) 0.23 (0.07-0.80), p = 0.02. The rates of pain-free women at six postoperative months were indeterminate, 10/40 (25%) after serratus plane block vs. 19/40 (48%) after pectoral nerve-2 block, p = 0.06, adjusted odds ratio (95%CI) 2.9 (1.1-7.5), p = 0.03. Health-related quality of life at six postoperative months was similar after serratus plane and pectoral nerve-2 blocks, mean (SD) EQ-5D-3L scores 0.87 (0.15) vs. 0.91 (0.14), respectively, p = 0.21. The pectoral nerve-2 block reduced median (IQR [range]) morphine consumption in the first 24 postoperative hours from 6 (3-9 [1-25]) mg to 4 (2-7 [0-37]) mg, p = 0.04. However, acute pain scores after serratus plane and pectoral nerve-2 blocks were similar, median (IQR [range]) 23 (11-35 [0-70]) mm vs. 18 (11-27 [0-61]) mm, respectively, p = 0.44. Pectoral nerve-2 block reduced chronic pain 6 months after mastectomy compared with serratus plane block.

Clarification on chronic pain – a painfully persistent problem?

“…We thank Dr Versyck et al [1] for their thoughtful comments and reflections on our article [2]. We agree that the injection site is important for the effectiveness of both the PECS 2 and serratus plane blocks.…”

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We read with great interest the article by Fujii et al, which investigated the effect of the Pecs 2 block and serratus plane block on persistent pain after mastectomy [1]. We would like to compliment the authors for their efforts to shine light on one of the potentially debilitating sequalae of breast surgery [2], chronic post-mastectomy pain, as well as comparing two of the newer fascial plane blocks head-tohead.

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Clarification on chronic pain – a painfully persistent problem? A reply

“…However, it is uncertain which block is more effective. Although there was no difference in pain intensity at 24 h postoperatively between the two blocks, morphine consumption in the first 24 h postoperatively was higher following serratus plane block than the PECS 2 block .…”

“…We thank Dr Versyck et al. for their thoughtful comments and reflections on our article . We agree that the injection site is important for the effectiveness of both the PECS 2 and serratus plane blocks.…”

“…Major risk factors affecting chronic post‐mastectomy pain were axillary lymph node dissection, postoperative radiation therapy, younger age and pre‐operative pain. Our study included patients without pre‐operative pain . We assessed chronic pain of the ipsilateral arm, axilla, shoulder or chest at six postoperative months.…”