Abstract
This video illustrates the case of a 51-year-old woman who presented with sudden-onset
headache, vertigo, and nausea. Imaging revealed an epidermoid cyst of the posterior
fossa with mass effect upon the brainstem and displacement of the basilar artery.
This lesion was approached using a left-sided keyhole retrosigmoid craniotomy with
monitoring of the cranial nerves. This video illustrates the technique of internal
debulking of the cyst contents with minimal manipulation of the cyst capsule, which
is often densely adherent to the brainstem, cranial nerves, and vessels in the posterior
fossa. Resection of the capsule is often associated with a higher rate of cranial
nerve deficits. The tumor was removed completely, but the cyst capsule was left in
place. The patient had House–Brackmann grade II facial paralysis postoperatively and
complained of some diminished hearing in the left ear. Epidermoid cysts are benign
tumors, but the patient may experience much morbidity from their overly aggressive
resection, especially when the capsule is densely adhering to critical structures.
An alternate strategy is to decompress the contents of the epidermoid cyst, thereby
decompressing the brainstem and converting this disease process into a chronic disease
that may require reoperation in the long term. Given the tight confines of the posterior
fossa, aggressive internal decompression of tumors and mobilization from the brainstem
and adjacent nerves are key to avoiding injury to the brainstem and cranial neuropathies.
In patients with benign tumors, the goal of the operation should be decompression
of the brainstem and preservation of cranial nerve function.
The link to the video can be found at: https://youtu.be/nk8-VztB0OI.
Keywords
retrosigmoid - cerebellopontine angle - epidermoid
