Paediatric Scoliosis

Posterior Spinal Fusion (PSF) for Adolescent Idiopathic Scoliosis (AIS) is one of the most painful procedures in paediatric surgery.

With pain scores frequently hitting 6.6/10 on day one , getting the analgesia wrong leads to delayed mobilisation, chronic post-surgical pain, and prolonged opioid use.

The Bottom Line

The Basics & The Surgery

AIS affects up to 5.2% of children aged 10-18. Surgery is indicated when the Cobb Angle (the degree of curvature) exceeds >40°.

Anaesthetic Implication: Intraoperative Neurophysiological Monitoring (MEPs and SSEPs) is standard of care to detect neurological damage.

• Avoid: Volatile agents (Sevoflurane reduces MEPs).
• Use: TIVA (Propofol/Remifentanil)

The Evidence: What Works?

NSAIDs: The Safety Myth-Bust

Historically, surgeons avoided NSAIDs due to fears of bleeding and non-union (pseudarthrosis). The evidence now suggests these fears are unfounded in paediatric scoliosis.

• Ketorolac: Reduces pain scores and opioid consumption.
• Safety: No increased risk of pseudarthrosis or bleeding-related reoperation.

Neuraxial: IT Morphine vs. Epidurals

Intrathecal (IT) morphine is the clear winner here.

• IT Morphine: Lasts 12–18 hours, reduces opioid use, and is technically easier (often placed by the surgeon).
• Epidurals: High failure rates (up to 37%) and catheter migration are significant issues. A Cochrane review found the evidence for safety is "uncertain".

Regional: The Rise of the ESP Block

The Erector Spinae Plane Block (ESPB) is rapidly gaining traction.

• Efficacy: RCTs in 2024 showed bilateral ESPB reduced pain scores at all time points up to 48 hours compared to standard IV analgesia.
• Safety: Crucially, ESPB does not interfere with neuromonitoring.

Adjuncts

• Gabapentin: Efficacious. Pre-operative loading (15 mg kg−1) followed by post-op maintenance reduces opioid consumption and pain scores.
• Ketamine: Surprisingly, evidence in scoliosis specifically is mixed. Three out of four RCTs showed no difference in opioid consumption.
• Methadone: Promising for reducing opioid consumption, but requires careful dosing due to rapid redistribution (levels drop below therapeutic range within 1 hour if not followed by an infusion).

A Practical Protocol (CHI Crumlin Protocol)

Based on the protocol published in the review, a robust postoperative plan includes:

Day 0 (Post-Op)

• Regular: Paracetamol IV, Gabapentin (if started pre-op), Dexamethasone (anti-emetic/anti-inflammatory).
• Rescue: Morphine PCA (no background if IT morphine used).
• Adjuncts: Ketamine infusion / Clonidine IV as required.

Day 1

• Transition: Introduce NSAIDs (Diclofenac/Ketorolac) and transition to oral opioids (Oxycodone).
• Mobilise: Physiotherapy and removal of catheters.

Test your knowledge with these Single Best Answer questions.

A 13-year-old female presents to the chronic pain clinic with Adolescent Idiopathic Scoliosis (AIS). She reports back pain and cosmetic concerns. You are reviewing the indications for surgical management to counsel the patient and her parents. Based on current guidelines, at which Cobb angle is surgical intervention (Posterior Spinal Fusion) typically considered?

A. >10∘ 

B. >20∘ 

C. >30∘ 

D. >40∘ 

E. >50∘

Correct Answer: D (>40∘)

Rationale: * D is correct: Surgical intervention is considered for patients with a Cobb angle >40∘. * A is incorrect: A Cobb angle of >10∘ is the definition of scoliosis, not the threshold for surgery.

You are discussing the postoperative analgesic plan for a 14-year-old undergoing Posterior Spinal Fusion (PSF) with the orthopaedic surgeon. The surgeon expresses reluctance to prescribe Ketorolac due to concerns regarding bone healing. According to the recent evidence reviewed in BJA Education (2025), which of the following statements is true regarding NSAID use in this specific population?

A. Ketorolac use is associated with a statistically significant increase in pseudarthrosis in paediatric patients.

B. Ketorolac increases the rate of reoperation due to bleeding complications.

C. Ketorolac should be withheld for the first 48 hours to prevent non-union.

D. High-dose Ketorolac is associated with pseudarthrosis in adults, but this risk has not been validated in children.

E. NSAIDs have no effect on postoperative opioid consumption in PSF.

Correct Answer: D

Rationale:  D is correct: Adult studies have shown high-dose ketorolac is associated with pseudoarthrosis, but the same risks have not been found in paediatric populations. Retrospective reviews found no increased risk of pseudarthrosis in children receiving ketorolac. 

A is incorrect: Evidence suggests no increased risk of pseudarthrosis in children.
B is incorrect: Ketorolac did not significantly increase bleeding-related complications such as reoperation. 
E is incorrect:Ketorolac reduces postoperative pain scores and morphine consumption.

A department is reviewing its protocol for scoliosis surgery. They are debating between using Epidural catheters versus Intrathecal (IT) Morphine. Which of the following is cited as a significant limitation specifically regarding the use of epidural catheters in paediatric PSF surgery?

A. Epidural analgesia causes a higher rate of respiratory depression than IT morphine.

B. Epidural catheters have a reported failure rate as high as 37%.

C. Epidural analgesia significantly interferes with Somatosensory Evoked Potentials (SSEPs).

D. IT Morphine provides a shorter duration of analgesia than a single-shot epidural.

E. Epidural catheters are associated with a higher rate of chronic postsurgical pain.

Correct Answer: B

Rationale: B is correct: The text highlights that concerns related to epidural catheters include block failure, with one study citing a failure rate as high as 37%. Catheter migration (inward and outward) is also a significant concern. A is incorrect: Respiratory depression occurred more frequently in the epidural group in a study comparing it to IT morphine. D is incorrect: IT morphine lasts 12–18 hours, whereas the text implies epidurals require catheters for continuous effect, which are prone to failure.

An anaesthetist administers a single intravenous bolus of Methadone (0.25 mg kg−1) at induction for a paediatric spinal fusion. Postoperatively, the patient reports significant pain within 60 minutes of arrival in recovery. What is the most likely pharmacokinetic explanation for this finding?

A. Rapid elimination of Methadone in adolescents.

B. Rapid redistribution of Methadone leading to sub-therapeutic plasma concentrations.

C. Acute opioid tolerance caused by intraoperative Remifentanil antagonism.

D. Genetic polymorphism of CYP2B6 resulting in ultra-rapid metabolism.

E. The dose administered was significantly below the recommended analgesic threshold.

Correct Answer: B

Rationale: B is correct: A pharmacokinetic study showed that after a bolus of 0.25 mg kg−1, mean methadone concentrations dropped below the therapeutic threshold (58 μg L−1) by the first hour after administration. A is incorrect: Methadone has a long elimination half-life (24–36 hours); the drop in concentration is due to redistribution, not elimination.  E is incorrect: The dose of 0.25 mg kg−1 is within the standard range (0.1−0.3 mg kg−1) used in studies.

During a T4-L1 posterior spinal fusion, the neurophysiologist reports a significant decrease in the amplitude of Motor Evoked Potentials (MEPs). The mean arterial pressure is stable, and the depth of anaesthesia is appropriate. Which of the following analgesic adjuncts, if running as an infusion, is most likely to be the cause?

A. Remifentanil infusion at 0.2 μg kg−1 min−1 

B. Lidocaine infusion at 1.5 mg kg−1 h−1 

C. Dexmedetomidine infusion at 0.5 μg kg−1 h−1 

D. Ketamine infusion at 2 μg kg−1 min−1 

E. Intrathecal Morphine 5 μg kg−1 (given at induction)

Correct Answer: C

Rationale: C is correct: Infusion rates of Dexmedetomidine at 0.3−0.5 μg kg−1 h−1 have been observed to cause a significant decrease in MEP amplitude. A is incorrect: Remifentanil is commonly used specifically because it facilitates neuromonitoring. B is incorrect: Recent studies indicate IV lidocaine has no negative impact on neurophysiological monitoring. D is incorrect: Ketamine can actually increase evoked potential amplitude.

You are planning a multimodal analgesic regimen for a 15-year-old undergoing scoliosis correction. You decide to perform bilateral Erector Spinae Plane (ESP) blocks. Based on 2024 RCT evidence, which of the following outcomes can be expected compared to standard IV analgesia?

A. Reduced pain scores for the first 6 hours only.

B. Reduced pain scores at all time points up to 48 hours postoperatively.

C. Significant attenuation of MEP signals during block performance.

D. Increased incidence of hypotension requiring vasopressors.

E. Superiority to Intrathecal Morphine in reducing length of stay.

Correct Answer: B

Rationale:  B is correct: RCTs published in 2024 showed that patients receiving ESPB had significantly lower postoperative pain scores at all time points examined up to 48 hours after surgery. C is incorrect: ESPB had no effect on intraoperative neuromonitoring.

A trainee asks about the evidence base for using perioperative Ketamine infusions specifically in paediatric scoliosis surgery. Based on the meta-analysis and RCTs reviewed, which statement accurately reflects the current evidence?

A. Ketamine consistently reduces postoperative opioid consumption in this specific cohort.

B. Ketamine provides Level 1 evidence for reduced pain scores at 24 hours in paediatric scoliosis.

C. Three out of four RCTs in this specific population found no difference in postoperative opioid consumption.

D. Ketamine is contraindicated due to negative effects on SSEP monitoring.

E. Ketamine is the single most effective agent for preventing chronic postsurgical pain in AIS.

Correct Answer: C

Rationale: C is correct: While Ketamine is effective in adult spinal surgery, 3 of 4 RCTs specifically in paediatric scoliosis found no difference in postoperative opioid consumption and pain scores between study groups. B is incorrect: The Level 1 evidence cited (meta-analysis) included all types of spinal surgery; the benefit in paediatric scoliosis specifically has "not been shown" consistently . D is incorrect: Ketamine tends to increase amplitude, not suppress monitoring.