Opioid Sparing Anesthesia in Cervical Spine Surgery

The aim of this double blind randomized study will be to investigate the effect of an opioid-free anesthesia regimen with a mixture of lidocaine and ketamine in the same syringe versus remifentanyl analgesia in cervical spine surgery.

Cervical spine surgery is associated with medium pain scores and perioperative disability. Ketamine and lidocaine have all proven but varied analgesic effects. High opioid consumption has been associated with multiple side effects. This double blind clinical trial aims to investigate the possible reduction of opioid use during lumbar spine surgery by administering ketamine and lidocaine. Sixty patients will be randomly allocated into two groups. The control group will receive a continuous infusion of remifentanil, while the Ketamine-Lidocaine (KL) group will receive a continuous infusion of ketamine and lidocaine, during the surgery and shortly after. Both infusions will be administered blindly. Fentanyl and morphine will be administered to each patient so as to maintain hemodynamic stability and pain relief. The study will eventually compare the need for bolus doses of fentanyl during the surgery and morphine shortly after in each group. Multiple hemodynamic parameters, analgesic consumption, possible side effects, patient satisfaction and the Oswestry low back pain disability questionnaire will be recorded.

Pain, Postoperative, Pain, Acute, Pain, Chronic, Pain, Nociceptive, Ketamine, Lidocaine, Analgesia, Analgesics, Cervical Spine Surgery

In the KL group, patients will be administered in a total volume of 20 mL,1mL/10 kg of the solution containing ketamine, lidocaine at predefined concentrations. As maintenance, they will be receiving 1mL/10kg/h of the aforementioned solution

In the Remifentanil group, patients will be administered in a total volume of 20 mL, 2 mcg/kg of fentanyl. As maintenance, they will be receiving 1 mL/10kg/h of a remifentanil solution

pain score by the use of Numeric Rating Scale (NRS) on arrival to PACU, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) at discharge from PACU, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) 3 hours postoperatively, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) 6 hours postoperatively, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

pain score by the use of Numeric Rating Scale (NRS) 24 hours postoperatively, ranging from 0 to 10, where 0 means "no pain" and 10 means "worst pain imaginable"

sedation will be assessed with a 5-point sedation scale, where: 1, patient perfectly conscious; 2, patient feels a little drowsy; 3, patient seems to be sleeping but immediately reacts to verbal stimulation; 4, patient seems to be sleeping but slowly reacts to verbal stimulation and 5, patient seems to be sleeping and does not react to verbal stimulation but does react to a stimulus such as shaking or pain

sedation will be assessed with a 5-point sedation scale, where: 1, patient perfectly conscious; 2, patient feels a little drowsy; 3, patient seems to be sleeping but immediately reacts to verbal stimulation; 4, patient seems to be sleeping but slowly reacts to verbal stimulation and 5, patient seems to be sleeping and does not react to verbal stimulation but does react to a stimulus such as shaking or pain

dose of required fentanyl intraoperatively to maintain systolic arterial blood pressure and heart rate within the 20% of baseline value

satisfaction from postoperative analgesia on a six-point Likert scale with 1 marked as minimal satisfaction and 6 as maximal satisfaction

Inclusion Criteria: Adult patents American Society of Anesthesiologists (ASA) class I-III elective spine surgery Exclusion Criteria: body mass index (BMI) >35 kg/m2 contraindications to local anesthetic administration systematic use of analgesic agents preoperatively chronic pain syndromes preoperatively neurological or psychiatric disease on treatment pregnancy severe hepatic or renal disease history of cardiovascular diseases/ arrhythmias/ conduction abnormalities bradycardia(<55 beats/minute) drug or alcohol abuse language or communication barriers lack of informed consent