Between 25% and 60% of women develop chronic neuropathic pain after mastectomy, a condition known as post-mastectomy pain syndrome (PMPS).

Symptoms
The symptoms associated with PMPS include shooting, stabbing, burning, and pins and needles sensations in the breast, axilla, or medial arm. Patients complain of symptoms of tightness and fullness in the axilla. Pain is aggravated by shoulder movement, stretching, straining, and direct contact with clothes.

CLASSIFICATION OF CHRONIC PAIN FOLLOWING BREAST SURGERY
Persistent pain in a patient with a prior surgical procedure for breast cancer can occur for many reasons, including tumor recurrence,
complications of radiotherapy or chemotherapy,
surgical injury.

Chronic pain that is a direct consequence of surgery can be either nociceptive, for example, resulting from injury to ligament or muscle or neuropathic in origin. Nociceptive pain usually resolves as damaged tissues heal, whereas pain from neuronal dysfunction can persist indefinitely.

Jung et al distinguished four different types of chronic neuropathic pain following breast cancer surgery due to surgical trauma:

Phantom Breast Pain

Phantom Breast Pain is pain experienced in the area of a removed breast. Patients commonly experience the sensation that the removed breast is still present after a radical mastectomy or a modified radical mastectomy.


Non-painful phantom breast sensation is a sensory experience of a removed breast that still feels present.

Phantom breast pain is a sensory experience of a removed breast that is still present and is painful.

Neuroma pain
Neuromas can form whenever peripheral nerves are severed or injured.
Neuroma pain may be more common following lumpectomy than mastectomy.
Other nerve injury pain
Other nerve injury pain may result from damage or traction to the medial and lateral pectoral, long thoracic, or thoracodorsal nerves, which are routinely spared but may be injured by scarring or by traction during mastectomy.
Post-mastectomy pain syndrome (PMPS)
It is described as distinct syndrome of pain and sensory abnormalities following mastectomy that they termed post-mastectomy pain syndrome (PMPS). In PMPS, pain is typically localized to the axilla, medial upper arm, and/or the anterior chest wall on the affected side. Damage to the intercostobrachial nerve, which can occur with axillary node dissection, has been considered the most common cause of PMPS. Intercostobrachial Neuralgia is pain often accompanied by sensory changes, in the distribution of the intercostobrachial nerve following breast cancer surgery with or without axillary dissection. The intercostobrachial nerves run from the chest wall through the axilla to innervate the shoulder and upper arm. With axillary node dissection, these nerves are impossible to spare.

at present intercostobrachial neuralgia (ICN) is a more appropriate term than PMPS for the neuropathic pain syndrome that appears to result from damage to the intercostobrachial nerve.

TREATMENT OF CHRONIC POST-MASTECTOMY PAIN
Non Pharmacological treatments
Non Pharmacological treatments like
TENs acupuncture may offer some symptomatic pain relief. Rehabilitative approach with a focus on gentle exercise, coping and pacing strategies and relaxation techniques have been shown to help patients manage their pain better.
Psychological treatments Anti neuropathic pain medications

INTERVENTIONAL TREATMENTS FOR POST-MASTECTOMY PAIN
Trigger point injections

Injection of local anaesthetic and steroid at the points of maximal tenderness can relieve chronic post mastectomy pain. Patients may need repeat injection in approximately 6 months.

Intercostal nerve blocks
Intercostal nerve block and pulsed radiofrequency ablation of the nerve under ultrasound guidance can be used.

Serratus plane block (SPB)
SPB is a novel peripheral nerve block technique to provide analgesia for breast and thoracic wall surgeries.
Lateral and anterior cutaneous branches of the second to sixth intercostal nerves pierce the external intercostals and serratus anterior in the anterior-to-mid axillary line.
SPB involves deposition of local anesthetics in a plane that is superficial to or deep underneath the serratus anterior muscle in the mid-axillary line between the fourth and fifth ribs.

This technique achieves blockade of sensory nerves through the axillary compartment.

SPB is surely effective for the T2 intercostobrachial nerves, which play an important role in the pathology of chronic post-mastectomy pain.

Pectoral nerves (PECS) II block was introduced as a deposition of local anesthetics in 2 layers, with one layer located between the intercostal and serratus anterior muscles and the other between the pectoralis major and minor at the level of the third and fourth ribs. Both SPB and PECS II blocks provide some degree of analgesia blocks are effective for somatic pain.

Botox injections
Botox injections under ultrasound guidance targeting the pectoral muscles, latissimusdorsi and serratus anterior muscles can help in the management of chronic post breast surgery pain.

Pulsed radiofrequency of dorsal root ganglion
Pulsed RF of the DRG has been shown to be superior to both medical management and pulsed RF of the intercostal nerve in the treatment of patients suffering from chronic post-surgical chest

pain. However, given the inherent risk of performing thoracic interventional procedures, it cannot be recommended it as a first-line treatment and should be reserved for those patients refractory to pharmacotherapy.

Thoracic Epidural Infusion
To break the pain cycles in resistant cases

Sympathetic Block
To control the sympathetic mediated pain by blocking Stellate or thoracic ganglion blocks.