Cervical Epidural and Stellate Ganglion Block in Upper Limb Complex Regional Pain Syndrome

Inclusion Criteria: 1. Patients aged more than 21 years old of both sexes with American Society of Anesthesiologists I and II 2. Upper limb trauma patients with pain disproportionate to the degree of tissue injury and persists beyond the normal expected time for tissue healing 3. Patients diagnosed as (Complex Regional Pain Syndrome ) based on Budapest criteria There should be at least one symptom or sign in three of the four previous categories that can not be explained by other diagnosis. 4. The average daily pain intensity required on Numerical Rating Scale is 7 or more for at least 3 months despite of standard therapy which includes: (pharmacologic therapy Non-steroidal anti-inflammatory drugs, Antiepileptic drugs(AEDs), antidepressants), as well as physical therapy and psychiatric care. Exclusion Criteria: * Patient refusal * Patients with unstable psychological or psychiatric conditions, including: untreated bipolar disorder, post-traumatic stress disorder, major depression, severe personality disorder and psychotic illness * Patients have recently undergone major interventional pain procedures, such as nerve blocks or implantable therapies. * Patients with known drug dependency or substance use disorder specifically related to ketamine or other psycho-stimulant drugs * Patients with previous severe reactions, contraindication or allergy to ketamine * Patients with hepatic or renal impairment * Active infection at the injection site * Known allergies to medications * Previous neck surgeries * Raynaud's disease or Raynaud's phenomena * Coagulopathy