Discussion
thoracic paravertebral block, erector spinae block, thoracic innervation, pain, brachial cutaneous nerve
BANG, SYNDROME, COMPLICATIONS
Post-mastectomy pain syndrome (PMPS) is a common problem following breast surgeries, and its prevention and management remain challenging with limited research available [To the best of our knowledge, this study is the first to compare two volumes (20 ml versus 30 ml) of erector spinae block (ESB) in patients with PMPS and assess the levels of dermatomes covered by each volume. We also evaluated the volume that provided the best pain improvement and patient satisfaction in women with post-mastectomy pain.In our study, we found that the 30 ml solution resulted in a greater number of vertebral blockade levels compared to the 20 ml solution. This interesting finding suggests that the larger volume group may have better pain relief and patient satisfaction. This contributes valuable information to the literature and calls for further large-scale studies to confirm our results.The mechanism of action of ESB has been investigated radiologically and anatomically on fresh cadavers. Forero et al. found that ESB spreads to the dorsal and ventral rami of the spinal nerves [Considering the anatomical distribution of thoracic innervation, it is important to note that the areas affected by PMPS receive innervation from different dorsal roots of the spinal nerves. The medial brachial cutaneous nerve arises from C8 and T1 levels and innervates the upper medial aspect of the arm, while the axilla is innervated at the T2 level [Aoyama et al. compared ESB with 20 ml of 0.5% ropivacaine to paravertebral block for breast surgery and found that the percentage of patients in the paravertebral block group who developed T3 and T5 blockade was higher than in the ESB group [Bang et al. studied the effectiveness of thoracic ESB as analgesia after lung lobectomy and performed the block at the T5 level with a total volume of 30 ml, consisting of a mixture of 15 ml of 0.75% ropivacaine and 15 ml of saline. They observed sensory blockade in the T2-8 dermatomes, with numeric rating scale (NRS) scores of 1 at rest, 3 during active coughing, and 1 during deep breathing [Hasoon et al. reported pain relief for three months in an elderly female with PMPS after ESB at the T5 level using 2 ml of non-ionic contrast, 1 ml of 40 mg/ml of methylprednisolone, and 9 ml of 0.25% bupivacaine [In contrast to our results, Fang et al. stated that ESB with 20 ml of 0.25% bupivacaine alone was insufficient to relieve pain and required additional postoperative sufentanil to achieve effects similar to those of thoracic paravertebral block for patients undergoing thoracotomy. However, they approved that ESB has less frequent side effects [Regarding the reported side effects, Azmy et al. stated that complications of ESB are infrequent because the site of the block is far away from the spinal cord, the pleura, and any major blood vessels [