Effect of Ultrasound Guided Erector Spinae Plane Block Versus Ultrasound Guided Serratus Anterior Block on the Incidence of Post Mastectomy Pain Syndrome, Randomized Double Blinded Controlled Study

Background and Rationale:

Breast cancer is the most common malignancy among females with incidence of about 2.1 million women each year. It is the most common cause for cancer-related deaths among women. (1) Modified Radical Mastectomy (MRM) is one of the main surgical treatments of breast cancer. It is account for 31% of all breast surgery cases (2). Nearly 40-60% of breast surgery patients experience severe acute postoperative pain, with severe pain persisting for 6-12 months in almost 20-50% of patients (post mastectomy pain syndrome)(3-4). Pain can be severe enough to cause long-term disabilities and interfere with sleep and performance of daily activities leading to complications such as: shoulder adhesive capsulitis (frozen shoulder), complex regional pain syndrome (causalgia) and altered sensation creating an economic burden for the health care system (5-8).

The International Association for the Study of Pain (IASP) defines PMPS as pain which persists more than 3 months after mastectomy/lumpectomy affecting the anterior thorax, axilla, and/or medial upper arm.It usually describes as feeling of burning, stabbing, and pulling around the treatment side(9) The underlying pathophysiology of PMPS is highly complicated and entangle both peripheral and central sensitization. Multiple risk factors involved in the development of PMPS including Acute postoperative pain ,Age < 40 years , Increased BMI ,Diagnosis at later-stage disease , Psychosocial factors (i.e., anxiety, depression, sleep disturbances, catastrophizing) Preoperative pain and Adjuvant therapy (chemotherapy, radiation therapy(10). Like other neuropathic pain conditions, the treatment is a difficult task (11), so the focus of current research is on perioperative measures that can mitigate the modifiable risk factors for PMPS and thereby prevent patients from developing PMPS in the first place. Recognizing the importance of postoperative pain management, a number of studies have looked at strategies with the potential to prevent the development of chronic pain following breast surgery including regional anesthesia. (12)

These regional techniques include: Intercostal nerve block, Pectoral nerve Blocks (PECI & PECS II) , Serratus Anterior Plane block (SAPB) and Erector Spinae Plane Block (ESPB). (14) Hypothesis: We hypothesize that Ultrasound guided erector spinae plane block is going to be more effective than ultrasound guided serratus anterior plane block in the prevention of postmastectomy pain syndrome in patients undergoing MRM as the injected local anesthetics acts on the dorsal and ventral rami of the thoracic spinal nerves and, thus, it is expected to block the sympathetic fibers leading to effective management of somatic and visceral pain.

Objectives: