Cervicomedullary Tumors

In general, most focal cervicomedullary tumors are considered benign in pathology. Common tumors of the cervicomedullary region include low-grade astrocytomas, gangliogliomas and ependymomas. They are typically well-delineated and benign tumors, typically amen­able to gross total resection.

Anaplastic astrocytomas with a diffuse growth pattern may also be encountered and are challenging to resect (biopsy can be done to establish a diagnosis).

Lesions that are stable clinically and radiographically, without signs of malignancy, may be initially managed in a non-operative manner with serial imaging and neurological evaluation.

The difficulty of surgical removal is correlated with the tumor's growth pattern, pathology and involvement of surrounding structures.

Cervicomedullary tumors often extend from the lower two-thirds of the medulla to the superior aspect of the spinal cord. Some anatomical barriers (e.g. pyramidal decussation, medial lemniscus, etc.) confine these benign tumors in the cervicomedullary region making them more accessible and resectable ( Figure 7.1 ).

Intraoperative monitoring and assessment of the functional integrity of neural pathways is typically recommended during surgery. This includes somatosensory evoked potentials, brainstem auditory evoked potentials, spontaneous EMG of the lower cranial nerves and motor evoked potentials.

A cartouche stimulation probe can be used over the dorsal medulla to find a non-eloquent safe entry zone to access the cervicomedullary lesion. This allows for detection of functional neural tissue overlying the lesion and the proximity of functional tissue to the tumor.