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Intraoperative Spinal Cord Monitoring Alert — FRCA Final MCQ

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HardPaediatric AnaesthesiaIntraoperative Spinal Cord Monitoring AlertFRCA Final

A 12-year-old girl weighing 35 kg undergoes posterior spinal fusion for scoliosis. Immediately after rod derotation, the neurophysiologist confirms a reproducible greater than 50% reduction in bilateral lower-limb motor evoked potential amplitudes. Upper-limb control responses are unchanged, and there has been no recent anaesthetic bolus or neuromuscular blocker. Her mean arterial pressure has fallen from 75 mmHg to 58 mmHg. What is the most appropriate immediate response?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Declare the alert, pause and partially reverse the latest correction, and restore MAP and oxygen delivery

Explanation lettering: D = shown as A · E = shown as C · A = shown as D · C = shown as E

A is correct. A reproducible bilateral lower-limb MEP deterioration immediately after rod derotation, with preserved upper-limb controls and marked hypotension, suggests compromised spinal cord perfusion rather than a global anaesthetic or technical effect. The whole team should be alerted, surgical manipulation paused and the latest corrective manoeuvre reversed while MAP is restored at least to the pre-alert level. Oxygenation, haemoglobin, temperature, anaesthetic depth, neuromuscular blockade and monitoring connections should also be checked. There is no evidence-based universal MAP threshold of greater than 80 mmHg for every child. Methylprednisolone is not the immediate treatment and is not recommended by NICE for traumatic cord neuroprotection. Mannitol and hyperventilation do not restore spinal cord perfusion. A wake-up test may be considered only if signals remain abnormal after systematic corrective measures.

Reference: Lewis SJ et al. Responding to Intraoperative Neuromonitoring Changes During Pediatric Coronal Spinal Deformity Surgery. Global Spine Journal. 2019;9(1 Suppl):15S–21S. https://pubmed.ncbi.nlm.nih.gov/23116091/