Maximizing surgical resection in revision surgery for an intramedullary spinal cord tumour using DTI/tractography and direct spinal cord stimulation: A technical note

Abstract

BackgroundIntramedullary spinal cord tumours are formidable lesions in spine surgery due to the high risk of postoperative deficits associated with surgical resection. Traditional MRI imaging fails to provide a 3-D rendering of the relationship between the tumour and spinal cord sensory and motor pathways; in contrast, DTI/tractography can show this relationship with the potential to reduce surgery-related morbidity. The use of intraoperative somatosensory evoked potentials (SSEP) and transcranial motor evoked potentials (MEP) have also been considered a standard of care to minimize neurologic complications of surgery. However, in situations where both baseline SSEPs and MEPs are unobtainable, D-wave and direct cord stimulation can become invaluable intra-operative tools. MethodsA 6 year old child presented with new growth from an incompletely resected thoracic intramedullary dermoid tumour. Pre-operative DTI/tractography images were obtained. During tumour resection, SSEP and MEP signals were unable to be obtained, however intraoperative monitoring of the spinal cord was undertaken with D-wave monitoring and direct cord stimulation. ResultsThis multimodal monitoring technique allowed identification of the corticospinal tracts intra-operatively and allowed safe tumour resection. Post-operative MRI revealed gross total resection and the patient returned to her pre-operative neurological baseline without incurring any further deficits. ConclusionsWe have presented a technical description of the clinical utility of DTI/tractography in surgical planning, and D-wave monitoring with direct cord stimulation as adjuncts in the resection of an intramedullary cord tumour. This is particularly useful in the scenario where TcMEP/SSEP signals cannot be obtained and in revision surgery for intramedullary spinal cord tumours.