1. NEMA Research, Pain management, Naples, FL, USA
2. Anesthesia and Pain Department, King Khalid University Hospital, College of Medicine, King Saud University, Riyadh, Saudi Arabia
3. Anesthesia Department, Medicine, Minia University & NCI, Minia, Egypt
4. College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
5. Paolo Procacci Foundation, Rome, Italy