• the number of patients who needed rescue analgesia [ Time Frame: 2weeks, 1, 2, 3 months ]
  the Cumulative use of rescue analgesics
• the number of patients who developed somnolence as a side effect of treatment [ Time Frame: immediately after the intervention, 2weeks, 1, 2, 3 months ]
  somnolence or excessive daytime sleepiness (EDS) refers to the tendency to fall asleep in inappropriate settings.
• the number of patients who developed dizziness as a side effect of treatment [ Time Frame: immediately after the intervention, 2weeks, 1, 2, 3 months ]
  a sensation of unsteadiness accompanied by a feeling of movement within the head
• The number of patients who developed nausea as a side effect of treatment [ Time Frame: immediately after the intervention, 2weeks, 1, 2, 3 months ]
  a feeling of sickness with an inclination to vomit.
• The number of patients who developed imbalance as a side effect of treatment [ Time Frame: immediately after the intervention, 2weeks, 1, 2, 3 months ]
  the state of being out of equilibrium or out of proportion
• The number of patients who developed constipation as a side effect of treatment [ Time Frame: immediately after the intervention, 2weeks, 1, 2, 3 months ]
  a condition in which there is difficulty in emptying the bowels, usually associated with hardened stool.
• The number of patients who developed pneumothorax as a side effect of treatment [ Time Frame: immediately after the intervention, 2weeks, 1, 2, 3 months ]
  an abnormal collection of air in the pleural space between the lung and the chest wall, diagnosed by chest xray
• Patient satisfaction [ Time Frame: 2weeks, 1, 2, 3 months ]
  Using score including 5-Excellent, 4-Very Good, 3-Good, 2-Fair, and 1-Poor

Chronic Post thoracotomy pain syndrome (PTPS) is defined PTPS as pain that develops or increases in intensity after a thoracotomy and persists beyond the healing process, that's to say at least 3 months after the initiating event. The pain has to be localized to the site of incision or, projected to the innervation territory of a nerve situated in this area or referred to a dermatome or Head's zone (after surgery/injury to deep somatic and visceral tissues The incidence of PTPS is 57% and 47% of patients at 3 and 6 months after thoracotomy, respectively.

Management of PTPS begins with prevention. Preventive strategies are based on multimodal preemptive and intraoperative analgesia. Treatment of PTPS is either pharmacologic treatment which is systematically initiated by first line drugs including tricyclic anti-depressants (TCA), serotonin-norepinephrine reuptake inhibitors (SNRI), gabapentinoids. Second-line treatments include topical lidocaine, capsaicin, and weak opioid analgesics (tramadol). Third line treatments consist of strong opioids (oxycodone, morphine) and subcutaneous botilinium toxin injection.

Other therapies for management of CPTP include such modalities as transcutaneous electrical nerve stimulation (TENS), Spinal cord and peripheral nerve stimulation, acupuncture and neurolysis using pulsed radiofrequency for intercostal nerve or dorsal root ganglio and cryoneurolysis for intercostal nerve. The mode of action of pulsed RF is not well-understood, but may include inhibition of excitatory C-fiber responses by repetitive, burst-like stimulation of A-delta fibers, global reduction of evoked synaptic activity and minor structural changes in nerve tissue; elicited by alterations in the function of the blood-nerve barrier, fibroblast activation and collagen deposition.

• Drug: lyrica, vronogabic (pregabalin)
  Patients would receive oral pregabalin is initiated at a dose of 75 mg twice daily and titrated up to 600 mg as tolerated by the patient at 1,2,3 weeks
  Other Name: lyrica, vronogabic
• Procedure: pulsed radiofrequency ablation of the dorsal root ganglion under fluroscopic guidance/ radiofrequency neurolysis/ radiofrequency denervation device name: Neuro Therm TM 1100
  Patients would receive pulsed radiofrequency ablation of dorsal root ganglion using the following settings: 2-Hz frequency, 20-ms pulses in a 1 second cycle, 120 second duration and 42°C temperature. Impedance ranges between 150 and 400 Ohms at all levels under fluroscopic guidance. For each pulsed RF application, the procedure will be repeated 4 times, for a total duration of 8 minutes
  Other Name: pulsed radiofrequency ablation of the dorsal root ganglion under fluroscopic guidance/ radiofrequency neurolysis/ radiofrequency denervation

• Active Comparator: lyrica, vronogabic (pregabalin)
  Patients would receive oral pregabalin
  Intervention: Drug: lyrica, vronogabic (pregabalin)
• Active Comparator: pulsed radiofrequency ablation of the dorsal root ganglion und
  Patients would receive pulsed radiofrequency ablation of dorsal root ganglion
  Intervention: Procedure: pulsed radiofrequency ablation of the dorsal root ganglion under fluroscopic guidance/ radiofrequency neurolysis/ radiofrequency denervation device name: Neuro Therm TM 1100

Inclusion Criteria:

• ASA physical status III or IV
• Persistent pain score ≥ 5 on VAS for 3 months or more, not responding to traditional OTC analgesics

Exclusion Criteria:

• Patient refusal
• The presence of pathology that could account for a majority of persistent symptoms (e.g. recurrent cancer)
• coagulopathy
• Uncooperative patients