Postoperative pain remains an important challenge for both patients and clinicians. Despite advances in pain management techniques, many patients continue to describe their pain as moderate to severe immediately after surgery. Poor postoperative pain control is associated with increased morbidity, functional impairment, and higher health care costs. While opioids currently represent the mainstay of treating surgical pain, their use is associated with significant side effects including respiratory depression, delayed recovery of bowel function as well as the potential for long-term use. Therefore, there is an urgent need to find new pain relievers with a safer side effect profiles. One such drug that has been receiving increasing attention is ketamine. Previous studies have focused on using intravenous ketamine postoperatively which requires a monitored setting but have ignored the oral form. By using the oral route of administration, ketamine could potentially be used by patients in a less resource-intensive manner with similar efficacy. Therefore, Investigators propose to conduct the Ketamine for Acute Postoperative Analgesia (KAPA) pilot study to examine the role of oral ketamine in improving recovery after spine surgery.

Pain after surgery remains an important challenge for both patients and clinicians. Despite advances in pain management techniques, many patients continue to describe their pain as moderate to severe immediately after surgery. Poor surgical pain control is associated with increased morbidity, functional impairment, and higher health care costs. While opioids currently represent the mainstay of treating surgical pain, their use is associated with significant side effects including respiratory depression, delayed recovery of bowel function as well as the potential for long-term use.

Therefore, there is an urgent need to find new pain relievers with a safer side effect profiles. One such drug that has been receiving increasing attention is ketamine. Previous studies have focused on using intravenous ketamine postoperatively which requires a monitored setting but have ignored the oral form. By using the oral route of administration, ketamine could potentially be used by patients in a less resource-intensive manner with similar efficacy. Therefore, Investigators propose to conduct the Ketamine for Acute Postoperative Analgesia (KAPA) pilot study to examine the role of oral ketamine in improving recovery after spine surgery.

The drug being studied in this trial is called Ketamine. Ketamine was initially developed as a unique anesthetic drug in the 1950's, clinicians later realized that when given in low doses, Ketamine can improve pain control after surgery and other chronic neuropathic conditions. It can be particularly helpful for patients whose pain is not adequately controlled with commonly used pain medications. Ketamine has also found new roles to aid in opioid tapering of subjects with opioid dependence and in the treatment of addiction.

Health Canada has approved Ketamine for medical use in hospital setting as an IV anesthetic agent for surgical procedures. However, there are currently no Health Canada approved oral Ketamine formulations. Although, it should be noted that oral ketamine is routinely used as part of standard order sets at several health institutions across Toronto and Canada.

The use of oral Ketamine in this study is experimental. Experimental means Health Canada has not approved the oral use of Ketamine but they have approved its use in this research study.

This study will look at how effective and safe Ketamine.

If participant decide to participate, the investigator will be in contact with your regular health care provider throughout the time that you are in the study and afterwards, if needed.

Participants are being asked to take part in this research study because they will be having elective spine surgery under general anesthesia and participants may develop pain after surgery.

The usual treatment for established pain after surgery is an approved intravenous opioid, such as hydromorphone, acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs). However, opiates usage carries significant risk of addiction and overdose, particularly with prolonged or increased dosing. Using a combination of medications to treat postoperative pain is quickly becoming more common in an attempt to avoid severe post-operative pain. Because of these limitations, it is important that Investigators look for new options to treat surgical pain.

Approximately 40 people will take part in this study at Toronto Western Hospital/UHN. Investigators expect the study to last for about 12 months.

Inclusion criteria

1. Patients aged 18-75 undergoing multi-level lumbar fusion and decompression
2. Planned overnight admission to hospital

Exclusion criteria

1. Patients taking greater than 90 milligram morphine equivalents
2. History of substance use disorder
3. Previous surgery within six months
4. Pre-existing renal or liver impairment
5. Chronic benzodiazepine use
6. Psychiatric disorder with current/active pharmacologic treatment
7. Inability to complete questionnaires

The KAPA trial will be a single center, blinded (participant, caregiver, investigator, outcome assessor), parallel arm, randomized controlled feasibility trial of patients undergoing spine surgery.