Preparation for Surgery for Supratentorial Choroid Plexus Tumors in Children

Indications for Surgery

• Treatment of hydrocephalus
• Diagnosis of the lesion
• Optimization of treatment: The goal of surgery is to remove a choroid plexus papilloma, thereby curing it, or, in the case of choroid plexus carcinoma, to achieve the best prognosis possible by its radical resection.

Preoperative Orders

Clamp time for CSF drain

• No need: The EVD does not need to be clamped before the operation.

Blood transfusion

• Anticipate high blood loss: The average blood loss during an operation is usually higher than the child’s blood volume (ranging from 5 to 600% of the blood volume) (23, 67, 80).
•  Exsanguination: The major complication from surgery is death following uncontrollable bleeding and has been reported in many series (65, 75). Blood should be available in the operating room at the start of the case.

Preoperative embolization

• Decrease operative blood loss: Large tumors or tumors showing important vascularization during the angiography can benefit from preoperative embolization to decrease blood loss in the operating room.
• Potentially curative: One case report describes the treatment of a choroid plexus papilloma by embolization alone and no recurrence at 16 months (91).

Surgical Planning

• Planned approach: Careful assessment of the location of the tumor is needed to choose the correct approach; this can be done using anatomical knowledge as well as fMRI in children who are old enough (motor and language for a left-sided tumor).
• Staged resection: Extremely large lesions occupying more than one ventricular cavity might require several staged approaches (23, 70), both because of blood volume loss during the surgery and because there might be a need for more than one approach to remove the tumor completely (e.g., transcortical and transcallosal).

Management of Hydrocephalus

Hydrocephalus can be a significant problem in these patients, both before and after surgery. The cause of hydrocephalus is still debated but is probably multifactorial.

• Overproduction of CSF: The tumor can produce an excessive amount of CSF.  There is one case report of a 10-month-old child with bilateral papillomas who produced more than 2000 ml/day of CSF (2, 28). Exceptionally metastatic growth may result in additional production of CSF.
• Obstruction of circulation: The tumor’s bulk may obstruct flow and trap CSF within the ventricles.  There can also be a disturbance of the resorption of the CSF.
• Treat preoperatively with EVD: An EVD can be used to temporize if the patient is acutely symptomatic because of elevated ICP. While EVD was part of the routine in the past, it is rarely used today (65, 75, 79).

Anesthetic Considerations

• Excessive blood loss: Because of the expected important blood loss, transfusion should be discussed with anesthesia before the start of the case.
• Elevated ICP at induction: Because the tumor usually presents due to elevated ICP and hydrocephalus, induction should take elevated ICP into account.

Ancillary/Specialized Equipment Required

• Operative microscope: The operative microscope is usually used for intraventricular tumors. It allows better lightning of the operative field, better angles for seeing the tumor, and better visualization of the vessels associated with the tumor.
• Ultrasonic aspirator: The ultrasonic aspirator is helpful when performing a central debulking and when the tumor is slightly more fibrous and difficult to aspirate with suction alone.
• Neuronavigation: Image guidance using a computer-assisted frameless stereotactic system can help in planning the approach. The shortest route to the tumor is usually the best approach, and the use of neuronavigation might maximize the craniotomy placement and minimize the corticectomy.
• EVD: If it has not been inserted as a preoperative treatment, an EVD is usually not needed, since CSF will be released as soon as the ventricle is reached. However, if it has been placed preoperatively, then it should be kept in place as some patients will require shunting.
• Intraoperative imaging: Intraoperative CT, MRI, or ultrasound may be useful if available to check the complete resection of the tumor.