Effect of Locally Administered Morphine and Bupivicaine on Acute and Chronic Postmastectomy Pain

Breast cancer is one of the most common cancer diagnoses in women and a significant cause of mortality and morbidity worldwide.Surgical treatment indicated in most patients. Persistent pain and sensory disturbances following surgery is a significant clinical problem with an average prevalence of 20-23.9%. Post-mastectomy chronic pain syndrome (PMPS) is defined as pain of neuropathic character located in the area of surgery and/or the ipsilateral arm, present at least 4 days per week, and with an average intensity of at least 3 on a numeric rating scale from 0 to 10. The pathological mechanisms may be related to patient characteristics, surgical technique and adjuvant therapy. Although the genesis of pain is multi-factorial, sectioning of the intercostobrachial nerve (a cutaneous branch of T1-2) is the nerve lesion diagnosed most often.

Uncontrolled acute postoperative pain is defined as an important risk factor for the development of chronic pain. Local anesthetics have been investigated in cancer breast patients through many routes; paravertebral blocks, thoracic epidurals, wound infiltration, topical lidocaine patch, and the topical application of EMLA( Eutectic Mixture of Local Anesthetics) cream on operation site. Most of above studies suggested a better outcome in terms of reduced postoperative pain and improved patient satisfaction.

Opioids exert a local analgesic effect is based on several observations: • Nociceptive afferent nerve fibers contain peripheral opioid receptors which are silent except in the presence of local inflammation. • Morphine and its metabolites are largely undetectable systemically when applied topically to skin ulcers, suggesting the analgesic effect is local • Peripheral opioid injections for local analgesia, such as intra-articular morphine after knee surgery, have been found to be effective in several trials. An effective topical opioid analgesic that could be applied to inflamed or open skin lesions would be a useful option for some patients where other options for pain relief have been exhausted.

Inclusion criteria

• female patients with cancer breast scheduled for modified radical mastectomy with axillary dissection

Exclusion criteria

• allergy to the study drugs
• significant cardiac, respiratory, renal or hepatic disease
• drug or alcohol abuse
• psychiatric illness that would interfere with perception and assessment of pain