For the antethoracic inferior block, the linear probe was placed parallel to the sixth rib at the inferior border of breast so that the surface of the rib was clearly visible (Figure 1). The needle was inserted in the plane of the ultrasound beam in a medial to lateral direction and advanced to the surface of the rib. After placement of the needle tip was confirmed by injecting about 2 mL of saline and visualizing the spread of saline between the surface of the rib and the pectoralis major muscle, 20 mL of 0.2% ropivacaine was injected. The spread of the local anesthetic was monitored in every direction by ultrasound (Figures 4 and 5).
We describe the successful use of a novel composite block called the complete antethoracic block for postoperative analgesia in a patient undergoing modified radical mastectomy. The patient’s postoperative course was uneventful, and she was discharged without the need for analgesics. Her overall experience with pain control was satisfactory.
We have performed the complete antethoracic block without any complications, including pneumothorax, in 53 patients receiving modified radical mastectomy. Moreover, all patients were satisfied with the extent of postoperative pain control. Supplemental analgesics were not required in about half of cases (26 of 53, 49.1%). If necessary, we provided pentazocine or flurbiprofen axetil as a supplemental analgesic. In such cases, the average time to request an analgesic was 3 hours 15 minutes from the end of surgery.
The pectoral nerve block alone is not sufficient to provide analgesia in the internal and lower mammary areas, although this is necessary after modified radical mastectomy. The present technique, the complete antethoracic block, comprises the antethoracic medial, antethoracic inferior, and antethoracic lateral blocks, affecting, respectively, the multiple anterior branches of the intercostal nerves, the anterior and lateral branches of the intercostal nerves (T5 and T6), and the pectoral nerves, lateral branches of the intercostal nerves, the long thoracic nerve, and the intercostobrachial nerve. This block provided postoperative analgesia over the internal mammary area, inferior mammary area, outer mammary area, and axilla (Figure 6).3–5 Therefore, we believe that this method is suitable for postoperative analgesia in patients undergoing modified radical mastectomy. It may also be useful during breast-conserving surgery in which the incision is located near the areola because the mammary papilla is abundantly supplied by the anterior and lateral branches of the intercostal nerves.5
Recently, the transversus thoracic muscle plane block has been reported to provide analgesia over the internal mammary area.6–8 However, because the puncture target is difficult to identify under ultrasound guidance and because the injection site is close to the pleura, which poses a risk of pneumothorax, this technique is difficult, and some practitioners do not feel comfortable performing it.4 In contrast, the puncture targets for the complete antethoracic block (ie, the superficial layer or points close to the surface of the ribs) are easily identifiable under ultrasound guidance and thus present a low risk of complications such as pneumothorax.
This case report has 2 limitations. First, the complete antethoracic block is fundamentally a single-injection, not continuous, technique. This makes it difficult to achieve complete pain relief during the entire postoperative course. Although the present block is superior to the pectoral nerve block alone in its clinical analgesic effect for modified radical mastectomy, there is little difference in the proportion of patients requiring supplemental analgesics between those receiving the pectoral nerve block alone and those receiving the complete antethoracic block (31 of 53, 58.5% vs 26 of 53, 49.1%, respectively). Second, we did not compare the analgesic effect of complete antethoracic block with that of the paravertebral nerve block, which is considered the gold standard regional anesthesia technique for patients undergoing breast surgery. Therefore, it remains to be established that complete antethoracic block definitely provides superior analgesia for modified radical mastectomy. However, our block has some advantages over other analgesia; it can be performed under general anesthesia in the supine position, and it has a low risk of pneumothorax or vascular puncture because the puncture targets lie on rib surfaces. Finally, this block is easily performed under ultrasound guidance because the puncture targets are superficial. Therefore, we believe that all anesthesiologists and patients would be more comfortable if the complete antethoracic block was administered. In future studies, it will be necessary to compare the analgesic effect of complete antethoracic block with that of the paravertebral nerve block.
In conclusion, we believe that the complete antethoracic block is suitable for postoperative analgesia in patients undergoing modified radical mastectomy and recommend its wide adoption for this type of surgery.
The authors thank Ms Chisato Takubo, our illustrator for Figures 1 and 6.
Name: Hidemasa Takahashi, MD.
Contribution: This author helped conceive and design the study, acquire, analyze and interpret the data, and write and edit the manuscript.
Name: Takeo Suzuki, MD, PhD.
Contribution: This author helped conceive and design the study, acquire the data, and revise the manuscript.
This manuscript was handled by: Raymond C. Roy, MD.
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