Complications of Therapies for Brainstem Gliomas in Children

Surgery

• Worsening symptoms: There can be transient or permanent worsening of preoperative neurological dysfunction. This reflects the vulnerability of tissues adversely affected by the tumor at the time of presentation.
• Hydrocephalus: Hydrocephalus can be secondary to the continued anatomical obstruction of the CSF pathway that remains after an incomplete surgical resection or it may be iatrogenic due to blood products or debris interfering with CSF outflow. CSF diversion via ETV or shunt may be required.
• Intranuclear ophthalmoplegia: This can cause a transient or permanent diplopia after surgical treatment of tumors of the pons. Persistent deficit may require referral for symptomatic treatment with prismatic eyeglasses.
• Impaired central respiratory function: This is due to excessive involvement of the medulla by tumor that is undergoing resection and/or manipulation during the resection of such tumors. Impairment of central respiratory function can be transient or permanent and can put the patient at risk for carbon dioxide retention and hypoxia. If not promptly recognized, further irreversible neurological injury or death may follow (61).
• Facial palsy: Facial palsy may occur when the floor of the fourth ventricle is violated in the vicinity of the facial colliculus. In addition to cosmetic consequences, corneal injury is a potential concern and should prompt consultation with ophthalmology and and/or plastic surgery.
• Abducens palsy: Abducens palsy can occur with binocular lateral gaze paralysis and resultant diplopia when the abducens nuclei is injured due to violation of the facial colliculus during surgical resection of lesions involving the floor of the fourth ventricle.
• Lower cranial nerve palsies (CN IX-XII): These palsies can result from resection of medullary or cervicomedullary tumors. The result can be a dysphagia, loss of cough and gag reflexes, and vocal cord paralysis, which place the patient at risk for microaspirations with resultant respiratory infections.
• Parinaud syndrome: This can occur after resection of midbrain tumors.

Radiation

Diffuse intrinsic pontine gliomas

• No complications anticipated due to shortness of survival: External beam radiation therapy is the standard care for patients with diffuse intrinsic pontine gliomas. No severe toxicity is expected for doses of 54–60 Gy at 1.8 Gy/fraction (involved fields that encompass the majority of the brainstem). Because of the short survival of patients with this disease, long-term toxicity is not relevant.