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Sagittal (a) and axial (b) T1W MR images showing a lipomyelomeningocele with asymmetric type of transitional lipoma in an 18-month-old child with low back swelling without any neurological deficits. The baseline mMEPs (c) were unchanged at the end of surgery (d). However, the child developed weakness of left ankle with grade 2/5 power which improved to grade 3/5 a week after surgery and normal power (5/5) at one year follow-up
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Objective
This study documents the monitorability using different anesthesia regimes and accuracy of muscle motor evoked potentials (mMEPs) in children ≤2 years of age undergoing tethered cord surgery (TCS).Methods
Intraoperative mMEP monitoring was attempted in 100 consecutive children, ≤2 years of age, undergoing TCS. MEP monitoring was done unde...
Citations
Motor-evoked potential (MEP) responses are the most specific, reliable, and timely clinical intraoperative neurophysiologic monitoring (IONM) test to detect a patient’s changing motor status with a possible repetition every 10 s. MEPs, once confined to use in spine procedures, have expanded to procedures where rapid identification of central nervous system (CNS), spinal cord, and peripheral nerve motor function is critical for patient outcomes. Patient’s vulnerability is associated with surgical injury and pre-existing disease or disability (e.g., age, muscular dystrophy, neurovascular and peripheral vascular disease, and tumors). For example, with interventional radiology (IR), when embolizing vessels in a vulnerable area, MEPs are performed prior to and after occlusion to establish whether it is safe to embolize. Temporary motor loss indicates the vessel provides critical perfusion and embolization may cause permanent neurologic deficits. This principle of hypoperfusion/reperfusion applies during reconstructive spine surgery, all vascular and cardiac procedures, and tumor excision in neurologic tissue. The effectiveness of MEP monitoring is directly dependent onw developments in computer technology and anesthetic drugs like propofol. MEPs are uniquely capable of rapidly identifying injury and recovery. This chapter reviews these considerations and applications that have made MEPs a key component of multimodality intraoperative monitoring.
OBJECTIVE
The aims of this study were to characterize syringomyelia in patients with lipomyelomeningocele (LMMC) and investigate the association between the presence of a syrinx and patient neurological deficits.
METHODS
Patients with LMMC who had been admitted between 2007 and 2020 were included in the study. Syringomyelia on magnetic resonance imaging (MRI) was classified into three groups: true syrinx, early syrinx, and presyrinx. The correlation of clinical deficits (at birth, new onset, and progressive) and type of lipoma with the presence and type of syrinx was studied.
RESULTS
Among a total of 140 patients, the median age was 2.5 (IQR 1.3–9) years. Neurological deficits were present at birth in 75 (53.6%) patients, but 67 (47.9%) had new-onset deficits or progression of their birth deficits. The most common type of spinal lipoma was the transitional type (75.7%). Thirty-nine (27.9%) patients had a syrinx (37 with a true syrinx, 2 with an early syrinx), and 25 (17.9%) patients had a presyrinx. There was no significant correlation between the presence of a syrinx and patient neurological deficits. However, patients with a syrinx that was not adjacent to the lipoma (≥ 1 vertebral level away) had a higher incidence of deficits at birth (p = 0.045), whereas those with a syrinx spanning ≥ 5 vertebral levels had a higher incidence of progressive neurological deficits (p = 0.04). Six (75%) of 8 patients in whom serial MRI had shown syrinx progression had clinical worsening.
CONCLUSIONS
Syrinx location with respect to the spinal lipoma, syrinx length, and progressive syringomyelia may have clinical significance in patients with LMMC.
