Radiofrequency Thoracic Sympathectomy for Chronic Postmastectomy Pain; Randomized Placebo Controlled Study

Postmastectomy pain syndrome (PMPS) is a neuropathic pain that can follow surgical treatment for breast cancer, The antineuropathic medications (antidepressants and anticonvulsants) are disappointing and have low success rate. Continues Radiofrequency lesioning has been reported as treatment for several chronic pain conditions.The concept that the clinical effect of RF was caused by formation of heat had not been challenged. Thermocoagulation of nerve fibers would interfere with the conduction of nociceptive stimuli and pain would be relived. Thoracic sympathectomy has been done for many painful conditions that includes complex regional pain syndrome .It offers the benefit over stellate ganglion block as it blocks the Kuntz fibers that connect to the brachial plexus roots without passing through stellate ganglion.

Postmastectomy pain syndrome (PMPS) is a neuropathic pain that can follow surgical treatment for breast cancer including radical mastectomy, modified radical mastectomy,and segmental mastectomy (lumpectomy) . The pain is distributed in the anterior chest, axilla, and medial and posterior parts of the arm . This pain can be sufficiently severe enough to interfere with sleep and performance of daily activities.

Patients may develop an immobilized arm, which can lead to severe lymph edema, frozen shoulder syndrome, and complex regional pain syndrome. PMPS can result from surgical damage to the intercostobrachial nerve( the lateral cutaneous branch of the second intercostal nerve) that is often resected at mastectomy .

The etiology of persistent pain after mastectomy is unclear, although it is likely multifactorial and may be partially neuropathic in nature . Previous reports of PMPS have suggested a limited number of potential risk factors, which are inconsistent among studies . While surgical factors, including more extensive surgery (mastectomy), axillary lymphnode dissection, and reconstruction have been postulated as important risk factors for chronic pain, many studies do not support this association. Adjuvant treatment, such as radiation, chemotherapy, and hormonal therapy, has also been occasionally associated with persistent pain .

Among demographic factors, younger age correlates with increased incidence of persistent pain in some studies but not others .

The antineuropathic medications (antidepressants and anticonvulsants) are disappointing and have low success rate, also have multiple drawbacks , specifically excessive sedation that affects daily life activities of those patients .

Radiofrequency has been used for interruption of the sympathetic chain to treat intractable pain in the sacral pelvic region or for management of visceral pain and on complex regional pain syndrome.

Radiofrequency has the advantage over surgical resection , in that it is more selective and may cause fewer complications.

Thoracic sympathectomy has been done for many painful conditions that includes complex regional pain syndrome , neuropathic pain of upper limb and it has been done for vasospastic diseases such as Raynaud's phenomenon it offers the benefit over stellate ganglion block as it blocks the Kuntz fibers that connect to the brachial plexus roots without passing through stellate ganglion .

Eligibility Criteria:
Inclusion Criteria:

* Patients with chronic post-mastectomy pain for at least 6 month post-operative
* Patients with VAS ≥ 5
* Patients on pregabalin dose ≥ 150 mg daily
* Patients treated with more than one line of anti-neuropathic drugs \[e.g. pregabalin+(tricyclic antidepressants or selective serotonin reuptake inhibitors ) or pregabalin+ tramadole\]
* Lymphedema of the upper limb

Exclusion Criteria:

* Patient refusal
* Coagulopathy
* Chest and back deformity hindering procedure impossible
* Infection at the introduction site of the needle