What fills the empty skull space after a brain hemispherectomy?

After the removal of a cerebral hemisphere in a brain hemispherectomy, the empty skull space is filled by a combination of Cerebrospinal Fluid (CSF), soft connective tissue, and sometimes the growth of new brain tissue.

1. Cerebrospinal Fluid: CSF is a clear fluid that surrounds and cushions the brain and spinal cord. After hemispherectomy, the remaining hemisphere can shift to fill part of the space, creating room for CSF to accumulate and fill the empty skull space.

2. Soft Connective Tissue: As the brain heals and adjusts to the loss of one hemisphere, the empty space may be filled with soft connective tissues such as arachnoid membranes and pia mater. These membranes provide support and protection for the remaining brain tissue.

3. Growth of New Tissue: In some cases, the remaining brain tissue may regenerate to a limited extent. This process, known as "post-hemispherectomy brain reorganization," can lead to the formation of new neural connections and functional compensation by the remaining hemisphere.

4. Skull Remodeling: Over time, the skull itself may undergo remodeling in response to the brain's loss. The bone may become thinner and the empty space may shrink as the brain adapts and shifts to fill the available space.

It is important to note that the specific outcomes after a hemispherectomy can vary depending on individual factors, such as the patient's age, the cause of the hemispherectomy, and the level of post-operative care and rehabilitation.