Ultrasound Guided Transversus Thoracic and Pectoral Nerve Block Versus Pectoral Nerve Block in Modified Radical Mastectomy

Background and Rationale:

Breast cancer is one of the common malignancies among women. Surgical resection of the primary tumor with axillary dissection is one of the main modalities of breast cancer treatment. The most common modality for anesthesia is general anesthesia with or without regional blocks. It has been reported that 40% of females report moderate to severe pain in the immediate post-operative period after breast cancer surgery. Acute post-surgical pain leads to delayed discharge from post-operative recovery area, impairs pulmonary and immune functions, increases risk of ileus, thromboembolism, myocardial infarction and may lead to increased length of hospital stay.

It is also an important factor leading to the development of chronic persistent post-operative pain in almost half of the patients. Post-operative pain, stress and use of morphine have been elucidated as factors responsible for increased risk of metastasis. Hence, effective perioperative pain management of patients undergoing breast surgery is essential. Regional blocks have been considered one of the modalities for effective perioperative pain control. They have an opioid-sparing effect and allow early mobilization and early discharge from the hospital.

Interfascial blocks score over regional anesthetic techniques such as Transversus Thoracic Plane Block and Pectoral Nerves (PECS) Block as they have no risk of sympathetic blockade, intrathecal or epidural spread, which may lead to hemodynamic instability and prolonged hospital stay. The transversus thoracic muscle plane block (TTP) block is a newly developed regional anesthesia technique which provides analgesia to the anterior chest wall. First described by Ueshima et al. in 2015, the TTP block is a single-shot nerve block that deposits local anesthetic in the transversus thoracic muscle plane between the internal intercostal and transversus thoracic muscles. TTP block targets the anterior branches of the intercostal nerves (T2-6).

Pectoral plane blocks are recently described . PECS block involves deposition of local anesthetic drug between muscle planes. PECS I block, between Pectoralis Major and Minor at third rib level, and PECS II block, the drug is deposited between Pectoralis minor and Serratus anterior muscle.