Comparison of intraoperative neurophysiological monitoring methods for lumbosacral lipoma surgery in infants.

ABSTRACT

BACKGROUND: Stable intraoperative neurophysiology monitoring of infants, especially very young infants, is challenging. In this study, motor evoked potentials (MEPs), the bulbocavernosus reflex (BCR), and somatosensory evoked potentials (SEPs) were simultaneously monitored in infants with lumbosacral lipomas, and these methods were compared retrospectively. METHODS: A total of 21 surgeries performed for lumbosacral lipoma in patients less than 1 year old were studied. The mean age at surgery was 133.8 days (range 21-287 days; ≤ 120 days 9 cases, > 120 days 12 cases). Transcranial MEPs were measured in the anal sphincter and gastrocnemius, and tibialis anterior and other muscles were added as needed. The BCR was measured by the electromyogram of the anal sphincter muscle with stimulation of the pubic region, and SEPs were measured from the waveforms of stimulation of the posterior tibial nerves. RESULTS: For the BCR, stable potentials could be recorded for all 9 cases at ≤ 120 days of age. In contrast, for MEPs, stable potentials could be recorded in only 4 of 9 cases (p < 0.05). For all patients > 120 days of age, MEPs and the BCR were measurable. SEPs were undetectable in some patients regardless of age. CONCLUSION: The BCR could be more consistently measured than MEPs in infant patients with lumbosacral lipoma at ≤ 120 days of age.