Adolescent Idiopathic Scoliosis (AIS)
Conditions
Keywords
Adolescent, Analgesia, Ketamine, Morphine, Pain management, Pain-controlled, Spinal fusion
Brief summary
The goal of this clinical trial is to evaluate whether adding low-dose ketamine to PCA morphine reduces opioid requirements after posterior spinal fusion surgery in adolescent idiopathic scoliosis patients. Selected patients aged 10-18 years undergoing elective AIS surgery at University Malaya Medical Centre will be randomised to ketamine-morphine or morphine-only PCA. The primary outcome is cumulative morphine consumption at 48 hours, with secondary outcomes including pain scores, opioid-related adverse effects, time to ambulation, and patient satisfaction. This study aligns with national priorities for safe opioid stewardship and enhanced peri-operative care in Malaysia.
Detailed description
Posterior spinal fusion (PSF) is the definitive surgical treatment for patients with scoliosis. However, the procedure involves extensive tissue dissection, resulting in significant postoperative pain. Although patient-controlled analgesia (PCA) with intravenous morphine remains the current standard, the large doses required are frequently associated with side effects such as nausea, vomiting, pruritus, and sedation \[4-6\]. These complications delay mobilisation, prolong hospital stay, increase healthcare costs, and may contribute to opioid tolerance, undermining effective pain control. Enhanced Recovery After Surgery (ERAS) protocols strongly promote multimodal analgesia, which combines opioid and non-opioid agents to achieve synergistic pain relief while minimising opioid exposure. This strategy has been shown to reduce side effects, improve recovery, shorten hospital stay, and lower the risk of opioid-related tolerance, hyperalgesia, and potential long-term dependence. Despite these advantages, evidence for the use of ketamine-morphine PCA in scoliosis surgery remains limited, and subanaesthetic ketamine-though effective intraoperatively as an opioid-sparing agent-remains underutilised in postoperative PCA regimens. Our previous study demonstrated that co-administration of subanaesthetic ketamine (0.5 mg/kg) at induction reduced postoperative pain sensitivity and hyperalgesia typically associated with high-dose remifentanil infusion, a strong opioid analgesic \[13\]. This finding underscores the potential role of ketamine as an opioid-sparing adjunct. Building on this, we propose a single-centre, double-blind, randomised controlled trial in 114 idiopathic scoliosis patients undergoing elective PSF at University Malaya Medical Centre. Participants will be randomised to receive PCA containing ketamine-morphine (1 mg/mL + 1 mg/mL) or morphine (1 mg/mL) alone, with identical syringes to ensure allocation concealment. The primary endpoint is cumulative morphine consumption at 48 hours, while secondary outcomes include pain scores, opioid-related side effects, time to ambulation, and patient satisfaction. This study aims to provide the first Malaysian evidence on an opioid-sparing PCA regimen, addressing national ERAS priorities and contributing to global opioid stewardship.
Interventions
COMBINATION_PRODUCTKetamine-Morphine PCA
The patient in this group will receive PCA Morphine (1mg/mL) with addition of Ketamine (1mg/mL) in comparison with the other group.
This patient will receive PCA Morphine only (1mg/mL).
Sponsors
University of Malaya
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Intervention model description
Informed consent (and assent where appropriate) will be obtained pre- operatively. An independent statistician will generate a computerised sequence in blocks of four. Sequentially-numbered opaque sealed envelopes (SNOSE; n = 114) will assign patients 1:1 to: * Group A Ketamine-Morphine PCA (K-M) * Group B Morphine-only PCA (M) An Acute Pain Service (APS) nurse not otherwise involved in the study will prepare identically labelled 30 mL polypropylene syringes (patient name + study ID only). Investigators, ward staff, surgeons and patients will remain blinded. In recovery, Group A receives a ketamine-morphine PCA solution (1 mg mL-¹ + 1 mg mL-¹); Group B receives morphine alone (1 mg mL-¹). Both devices deliver a 1 mL bolus, enforce a five-minute lock-out and cap delivery at 20 mL per four hours, with no background infusion.
Eligibility
Sex/Gender
ALL
Age
10 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Aged \> 10 years old 2. Idiopathic scoliosis scheduled for single-stage posterior spinal fusion (PSF). 3. American Society of Anaesthesiologists (ASA) physical status I-II.
Exclusion criteria
1. Known hypersensitivity to morphine, ketamine or formulation excipients. 2. Hepatic dysfunction (ALT or AST \> 2 × upper limit of normal). 3. Renal impairment (eGFR ≤ 60 mL min-¹ 1·73 m-²). 4. Uncontrolled asthma or severe restrictive lung disease. 5. Cardiac disease or clinically significant arrhythmia. 6. Epilepsy. 7. Intellectual disability precluding PCA use. 8. Chronic opioid therapy or pre-operative pain \> 3 months. 9. Concomitant monoamine-oxidase inhibitor or tricyclic antidepressant therapy. 10. History of severe postoperative delirium.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cumulative Morphine Consumption | From end of surgery (Hour 0) to 48 hours post-operation (Day 2). | Total amount of intravenous morphine (in milligrams) administered via the Patient-Controlled Analgesia (PCA) device. This includes both the demand doses and any clinician-administered boluses. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Post-operative Pain Intensity | At 6, 12, 18, 24, 30, 36, 42, and 48 hours post-operatively. | Patient-reported pain intensity measured using a Visual Analogue Scale (VAS). The scale ranges from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity. |
| Incidence of Opioid-Related Adverse Events (ORAEs) | From the end of surgery through 48 hours post-operatively. | The number of participants experiencing one or more of the following opioid-related adverse events: nausea, vomiting, pruritus (itching), excessive sedation (defined by a Richmond Agitation-Sedation Scale (RASS) score of -1 and below), or respiratory depression (respiratory rate \< 8 breaths per minute). |
| Duration of Hospital Stay | From date of surgery until hospital discharge (approximately 3-7 days). | The total number of days from the date of surgery (Day 0) to the date of hospital discharge. |
| Time to First Post-operative Flatus | Up to 48 hours post-operatively. | The time interval (in hours) from the end of surgery until the patient first reports the passage of gas (flatus). This serves as a proxy for the resolution of post-operative ileus. |
| Time to First Ambulation | Up to 48 hours post-operatively. | The time interval (in hours) from the end of surgery until the patient first takes steps outside of their bed with or without assistance. |
| Patient Satisfaction With Pain Management | At the time of hospital discharge (approximately Day 3 to Day 7 post-operatively). | Patient-reported satisfaction with their pain management experience using a 5-point Likert scale. The scale consists of: 1. = Very Dissatisfied 2. = Dissatisfied 3. = Neutral 4. = Satisfied 5. = Very Satisfied Total scores range from 1 to 5, where higher scores indicate greater satisfaction with the pain management protocol. |
Countries
Malaysia
Contacts
CONTACTMUHAMMAD FAEEZ BIN MOHD YUSOH, MBBS
PRINCIPAL_INVESTIGATORSITI NADZRAH BINTI YUNUS, MBBS
University of Malaya
Outcome results
None listed