A Novel Method to Predict Early Neurologic Recovery after Pediatric Spine Surgery.

Sir,

Pediatric spinal extradural hemorrhage (EDH), though rare, can result in serious complications if diagnosis and treatment are delayed.[1] Spontaneous bleeds, traumatic, bleed after lumbar puncture, spinal cord arteriovenous malformations or tumors, and anticoagulant therapy are etiopathogenic to the onset of spinal EDH.[2] Children with spinal EDH require emergency surgery. Intraoperative neuromonitoring (IONM) assists in the early detection of periprocedural spinal cord injury.[34]

A 10-year-old previously healthy child weighing 29 kg presented to us with sudden-onset weakness of the bilateral lower limbs progressing over 72 h. There was no significant past/family history or history of trauma. Clinical examination revealed spastic paraparesis and exaggerated deep tendon reflexes with 4/5 power of both lower limbs. Magnetic resonance imaging of the spine revealed a C6–D3 vertebral level posterior and left posterolateral epidural hemorrhage with spinal cord compression and spinal cord edema [Figure 1]. A clinical diagnosis of spontaneous spinal epidural hemorrhage (SSEH) was made, and the case was scheduled for emergency decompression of spinal hematoma under general anesthesia (GA). IONM, though a standard of care in our hospital, could not be mobilized due to exigency of time considering the emergency nature of the surgery.

Figure 1

Magnetic resonance image of the spine showing T2 hypo–isointense lesion from C5–D3 vertebral level with spinal cord compression and edema suggestive of extradural hemorrhage

In the operating room, GA was induced with intravenous (IV) fentanyl 3 mcg/kg and propofol 2 mg/kg. We obtained a baseline train-of-four (TOF) stimulation ratio before administering skeletal muscle relaxant. Baseline TOF ratio recorded was 50%. Subsequently, endotracheal intubation was facilitated with IV succinylcholine 2 mg/kg. Total IV anesthesia was used for GA maintenance with IV continuous infusions of fentanyl and propofol targeted to a bispectral index of 40–60. No further skeletal muscle relaxants were used during the maintenance of GA. The patient underwent decompressive spinal laminectomy and evacuation of hematoma from C6 to D3 level in the prone operative position under GA. TOF ratios were continuously recorded throughout the duration of surgical procedure at an interval of 10 min. TOF ratios increased intraoperatively to 90% on complete evacuation of hematoma. The surgical procedure was otherwise uneventful. The child had minimal spasticity of both lower limbs and could be ambulated by the 2nd postoperative day.

TOF ratio is classically used intraoperatively to monitor response and recovery to skeletal muscle relaxants.[5] A “fade” is characteristic of nondepolarizing skeletal muscle relaxant whereas TOF ratio is maintained, but the amplitude of response reduced, with the use of succinylcholine. The reduced baseline TOF and recovery in TOF ratio toward the completion of procedure in our case can, respectively, be attributed to symptomatic compressive myelopathy due to acute-onset SSEH and recovery in neurologic function after decompression of SSEH. Transcranial motor evoked potentials induced compound muscle action potentials can better predict such neuronal recovery,[4] however; this could not be used in our case considering the emergent requirement of surgery. It might be too premature to reach a conclusion that the increment in TOF ratios can predict neurologic recovery, though our case presents a simple yet novel such application of intraoperative TOF in acute spinal cord compressive myelopathy. Case series of TOF recovery in a larger number of patients with symptomatic myelopathy undergoing spinal decompression/instrumentation can consolidate our findings.

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Conflicts of interest

There are no conflicts of interest.