gms | German Medical Science

Objective: Extensive functional MRI, tractography and TMS are rarely used in children for the pre-operative work-up due to a presumed age related inability of children to perform accordingly in the scanner. We have shown, that a dedicated team in an appropriate environment is able to establish extensive functional imaging in awake children. This information, used for meticulous planning of surgical strategy, needs to be combined with intraoperative monitoring and imaging to optimize radicality and functional preservation

Methods: 21 pediatric patients were included with either low grad glioma (n=14) or cavernomas (n=7) of central region, (left) temporal (region) or midbrain. They received: fMRI for language detection with up to 4 paradigms (n=10), fMRI of motor cortex (n=11), tractography of motor tract (n=13), tractography visual tract (n=9) and arcuate fascicle (n=3). TMS was performed in 5 cases. High resolution intraoperative ultrasound was used in 19 operations and iMRI in 9.

Results: The desired functional or tract information was obtained in all cases. Surgical corridors were defined according to those results. In one case family decided against surgery, in all other results helped to balance risk. Extended intra-operative neuromontoring was used to confirm pre-operatively defined functionality if ever possible. On child underwent awake surgery because of arcuate fascicle involvement. Surgical goals according to intention to treat, which was mostly radical resection, could be achieved in all cases. There were no permanent new functional deficits except for partial loss of visual field in 1 case. Intraoperative ultrasound was most helpful, supplemented by iMRI, to achieve radicality.

Conclusion: Modern functional MRI and tractography are possible in awake children from 5 years onwards if an adequate study atmosphere is maintained. Tractography can be done for visual tract and arcuate fascicle visualization equally good as motor tractography. In combination with intraoperative neuromonitoring, high-resolution ultrasound and iMRI, this information enables the pediatric neurosurgeon to successfully „walk“ on the thin red line between radicality and functional impairment with reduced risks for harming. Thus, these time consuming additional techniques should be used whenever possible to make surgery of lesions in eloquent areas as radical and safe as possible and thus rewarding for surgeon and patient.