INTRODUCTION
Thoracotomy is considered as one of the most painful surgical procedures. The incidence of post thoracotomy pain syndrome (PTPS) 3 months after the surgery ranges between 22% and 67%.
Mostly small case reports and anecdotal reports are the only guidance in the literature.

Pain after thoracotomy may originate from both somatic and visceral afferents that lead to a cascade of neural activity which in turn contribute to the establishment of chronic pain and ultimately PTPS.

Somatic afferent input:
The skin incision, rib retraction, muscle splitting, injury to the parietal pleura, and chest drain insertion can, either individually or in combination, result in an escalation of nociceptive somatic afferent activity via the intercostal nerves.

Visceral afferents input:
Visceral afferent arises from the phrenic and vagus nerves after injury to the bronchi, visceral pleura, and pericardium.

TREATMENT
Conservative Management
Intercostal Nerve Injection / Denervation
Intercostal blocks (ICNB)

can be carried out above the Th10 level to localize the level of the pain with a target of > 50% reduction of pain during the local anesthetic blockade. The option of using advanced radiofrequency denervation (RF) can be considered depending on the outcome following the injections.
Selective thoracic nerve root treatment
Selective thoracic nerve root blocks (STNRBs) are helpful procedures. The most common indication is where there is radiculopathy and ICNBs have not relieved the symptoms.
After a successful STNRB (i.e. 50% reduction in pain), it is recommended to go on with pulsed radiofrequency of DRG for a definite pain relief.

Thoracic sympathetic blocks
Thoracic sympathetic blocks (TSBs) are usually helpful to diagnose and treat chronic benign and malignant thoracic and mediastinal pain syndromes, including neuropathic pain, chest wall pain, thoracic visceral pain, herpes zoster, post- herpetic pain, phantom breast pain. Diagnostic and therapeutic blocks of the sympathetic chain from T2-8 can be used in patients with severe intractable pain caused by cancer of the esophagus , heart, bronchi, trachea, lung, pleura or other chronic esophageal pain.

Paravertebral nerve blocks
PVNBs may offer good chronic pain control in some situations. It is a technique used to block spinal nerves, including the dorsal and ventral rami, and the sympathetic chain ganglion.

Thoracic Epidural Injection
It is also useful in some selected and resistant cases.

Neuromodulation The recent advancement in neuromodulation equipment and programming platforms opens the opportunity to use this technology to deal with the chronic pain condition. At present we have to rely on case studies and reported clinical evidence.