US-Guided PECS II Block Versus MTP Block for Postoperative Analgesia of MRM Sugery

This study aims to compare the analgesic efficacies of the modified pectoral plane block (PECS II) and the midpoint transverse process to pleura block (MTP), after modified radical mastectomy (MRM) surgery during the first 24 hour post-operatively by using the Visual Analogue Scale.

During Modified radical mastectomy (MRM), some of the nerves in the chest are severed. Most women have some level of pain in the days after the procedure. Severe acute postoperative pain following breast surgery not only increases the risk of persistent pain and affects recovery, it also leads to longer hospitalization and increased healthcare costs. Acute postoperative pain is an independent risk factor in the development of chronic post-mastectomy pain.

PECS-II is an interfascial plane block in which local anesthetic is injected between the pectoralis and serratus anterior muscles that blocks the long thoracic nerve as well as the pectoral, intercostobrachial, and inter-costal III, IV, V, and VI nerves. PECS-II is a less invasive and easier to perform alternative to thoracic paravertebral block (TPVB). This block, defined by Blanco et al., provides adequate and safe post-operative analgesia in the anterior chest wall after breast surgery. The most common complications are pneumothorax, infection, local anesthetic systemic toxicity (LAST)/allergy, vascular puncture, and failed block.

The MTP block was first described as a modified paravertebral block in 2017. The local anesthetic (LA) is administered between the transverse process and the pleura. This results in a LA spread to the dorsal and ventral rami in the paravertebral space through the fenestrations in the superior costotransverse ligament (SCTL) at the level of injection, and frequently to adjacent levels. The advantage of this novel technique is that it does not require identification of the SCTL and the injection point, which is midway between the pleura and transverse process, which makes this approach much safer than the conventional TPVB approach since the needle is farther from the vital structures like pleura, nerves, and vasculature. This technique is used for pain relief after mastectomy, thoracic, abdominal, and spinal surgery and was found effective due to its simplicity and lower risks compared to epidural analgesia.

Eligibility Criteria:
Inclusion Criteria:

1. Female patients scheduled for MRM.
2. Age eligible ≥ 40 \& ≤ 65 yrs.
3. Patients with American Society of Anesthesiologists (ASA) physical status I, II who will be scheduled for MRM surgery.

Exclusion Criteria:

1. Age \< 40 \& \> 65 years old.
2. Declining to give written informed consent.
3. History of allergy to the medications used in the study.
4. Contraindication to regional anesthesia (including coagulopathy (platelet count ≤ 80,000, INR ≥ 1.5) and local infection).
5. Severe hepatic impairment (INR ≥ 1.5, Bilirubin ≥ 2, Albumin ≤ 2).
6. Renal dysfunction \[Glomerular filtration rate \< 50ml/min calculated by Modification of diet in renal disease equation for GFR estimation\].
7. Psychiatric disorder.
8. Pregnancy.
9. Patient with history of thoracic spine surgery.