• brachial plexus
• truncal blocks
• acute pain

We would like to thank Dr Hongye et al for their interest in our article1; however, we would like to clarify that we did not suggest that pecoralis muscles/serratus blocks fail to provide some degree of sensory analgesia/anesthesia of the chest wall. We argued that this effect is the result of the spread of local anesthetic to the only possible nerve targets, the lateral branches of upper intercostal nerves. We disagree with Dr Hongye that the brachial plexus contributes to the sensory innervation of the chest wall. To support the brachial plexus contribution, the authors reference a paper that purportedly shows that a ‘pectoral nerve block’ improves a thoracic paravertebral block. However, this does not refute our argument since the results of such studies do not distinguish whether the observed effect comes from a block of the pectoral nerves or from spread to other targets. At the very best, this study would show that an injection into the thoracic fascial plane could help improve chest analgesia, without demonstrating how it is done. We would like to stress that a thoracic epidural block, which blocks spinal nerves and does not block the brachial plexus, can be used successfully as the only anesthesia for breast surgery and other chest procedures.2 As the accepted dermatome maps show, the chest and abdomen receive their sensory innervation from sequential spinal nerves leading to the familiar horizontal dermatomal stripes of the trunk in which the brachial plexus is not represented.3 If the brachial plexus also contributed to the sensory innervation of the chest wall, the dermatomal map would resemble more of a geographical map, in which the stripes would be interrupted by irregular-shaped patches of different sizes representing varied roots of the brachial plexus.

Finally, we did not say that ‘muscle pain likely stems from C fibers containing sensory afferent fibers’. We said that muscle pain is different than cutaneous pain, both in the way it is triggered and how it is conducted. Muscular pain is caused by muscle ischemia and it is afferently transmitted by C fibers present in motor nerves, where they represent about 25% of the total fibers.4 5 If surgical muscle trauma was an important component of surgical pain, then this muscle component, which in the chest would be transmitted by brachial plexus branches, could not be blunted by a thoracic epidural block. However, we know that thoracic surgery can be successfully performed under thoracic epidural or paravertebral blocks,2 6 7 demonstrating that the muscle component in surgical pain is either non-existent or not relevant.

Once again, we thank Dr Hongye and colleagues8 for the opportunity to clarify some of the issues related to our recent publication.