Artikel
Resection of pediatric low grade tumors in eloquent areas: Value of neuro-physiological guidance
Wert der neurophysiologisch geführten Resektion niedriggradiger kindlicher Tumore in eloquenten Arealen
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Veröffentlicht: | 30. Mai 2008 |
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Objective: To demonstrate the value of intraoperative monitoring (IOM) during resection of pediatric low grade tumors in eloquent areas such as spinal cord, brain stem, basal ganglia and primary motor cortex.
Methods: From 2004 to 2007 30 children (median 11 y., range 1–18 y.) with low grade tumors were surgically treated (ependymoma n=4, pilocytic astrocytoma n=15, other astrocytomas n=5, ganglioglioma n=3, DNET n=3). Patients underwent 38 surgical procedures for tumor resection. 5 had a second resection, 1 holocord tumor patient underwent 4 subsequent resections. IOM was performed in 25 patients during 33 surgical resections of tumors in the following eloquent locations: lower brainstem (medulla) n=7, cervical cord n=2, holocord n=2, cerebellum n=6, optic chiasm n=2, central region n=4, basal ganglia n=2. The extended IOM protocol included SEP and MEP, monopolar or bipolar stimulation, VEP, AEP and EMG of all involved motor cranial nerves. All patients had post-operative MRT scans either immediately or at 3 months. Neurological outcome was evaluated at discharge and at 3 months.
Results: All patients operated without IOM had radiological complete tumor resection without new neurological deficit. IOM data were available in all monitored patients regardless of age and tumor extension. Besides SEP and MEP monitoring, motor cortex, pyramidal tract, cranial nerves or their nuclei were monitored by either EMG or stimulated directly as needed. In case IOM potentials decrease >70% or disappeared, surgery was continued at a different spot. If IOM potentials recovered or reappeared, surgery continued in the critical area. Follow-up MRI scans demonstrated in 9 of 25 patients total tumor removal, in 13 near total resection and in 3 subtotal resection (2 holocord patients, 1 basal ganglia). Remnants progressed in 5 of 13 patients with near total resection, all underwent surgery and total removal was achieved in 3. Tumor progression in 2 of 3 with subtotal resection is currently treated with chemotherapy. Neurological status was unchanged or better following surgery in 26 of 33 interventions at discharge, at 3 months 4 of 7 patients with initial deterioration had improved to the pre-op functional status.
Conclusions: IOM guidance during resection of pediatric low grade tumors in eloquent areas was possible independent of the patient's age. It enabled aggressive resections with a final rate of 48% total removal and 40% near total removal with stability of the residual tumor, without long-lasting additional morbidity following surgery in 84% of patients.