Chronic Pain in Post-Mastectomy Patients; The Difference Between Pectoral Nerve (PECS I-II) and Erector Spinal Plane (ESP) Blocks

Chronic Pain in Mastectomy Patients; The Difference Between Pectoral Nerve Block (PECS I-II) and Erector Spinal Plane (ESP) Block

This study looks at two types of injections (called PECS and ESP blocks) to see which one works better for reducing pain after breast cancer surgery (mastectomy).

The main question it asks is: Which block is better at reducing pain after surgery - PECS or ESP? Women who had this surgery and received one of the two blocks were followed for three months. We looked at how much pain they felt, how much pain medication they needed, and whether they still had pain months later.

The results showed that both blocks helped with pain right after surgery. The ESP block lasted a little longer at first, but in general, both groups needed about the same amount of pain medicine. Three months later, about half of the patients still had some pain - especially those who had more extensive surgery or had nerve pain early on. There was no big difference between the two blocks when it came to long-term pain.

Despite advancements in breast cancer treatment, chronic postoperative pain-known as post-mastectomy pain syndrome (PMPS)-remains a common complication, with reported rates between 40-50%. It is typically neuropathic in nature and linked to factors such as axillary lymph node dissection, radiotherapy, and high levels of acute postoperative pain. Younger patients are at higher risk, and early neuropathic symptoms may predict long-term pain.

Regional anesthesia techniques, including PECS and erector spinae plane (ESP) blocks, are widely used to improve perioperative pain control and potentially reduce the incidence of chronic pain. These techniques are considered effective and low-risk adjuncts to general anesthesia.

This prospective observational study compares the impact of PECS I-II and ESP blocks on chronic pain development in patients undergoing modified radical mastectomy (MRM). The primary outcome is the incidence of pain at 3 months postoperatively (NRS ≥1). Secondary outcomes include acute pain scores, intraoperative fentanyl use, postoperative morphine requirements, and time to first analgesic. The study also explores associations between chronic pain and variables such as lymph node dissection, radiotherapy.

Findings aim to guide clinical practice in selecting regional anesthesia techniques that provide both immediate and long-term pain relief.

Inclusion Criteria:

• Scheduled to undergo modified radical mastectomy due to breast cancer
• Decision to perform PECS I-II or ESP block made independently from the study, as part of standard pain management
• Aged between 18 and 65 years
• American Society of Anesthesiologists (ASA) physical status classification I or II
• Female

Exclusion Criteria:

• Inability to perform the block (e.g., coagulation disorder, allergy to local anesthetics, infection at the injection site)
• Obesity (Body Mass Index > 35 kg/m²)
• Pre-existing neurological deficits
• Younger than 18 or older than 65 years
• ASA physical status classification III or IV
• Refusal to give informed consent