A drainage system in neurosurgery refers to a sterile, closed apparatus designed to evacuate pathological fluids—such as blood, cerebrospinal fluid (CSF), or exudate—from the cranial or spinal compartments.

It typically consists of:

• a catheter or tube inserted into the subdural, ventricular, or subarachnoid space,
• a connection to a sealed collection chamber or reservoir,
• and optionally a mechanism for negative pressure (vacuum) or gravity-assisted flow.

Drainage systems are essential in managing intracranial hypertension, preventing fluid reaccumulation, and aiding postoperative recovery.