Use of an endoscope in minimally invasive lesion biopsy and removal within the skull and cranial vault in two dogs and one cat.

CASE DESCRIPTION- 2 dogs and 1 cat underwent endoscopic-assisted intracranial procedures for lesion biopsy (1 dog and 1 cat) and definitive lesion removal (1 dog). CLINICAL FINDINGS- 1 cat was treated for an interhemispheric, pedunculated meningioma with an associated arachnoid cyst. Two dogs underwent endoscopic surgery procedures; 1 dog underwent removal of an intranasal dermoid cyst with extension to the olfactory bulb dura, and the other underwent lesion biopsy for histologic confirmation of suspected intracranial granular cell tumor. TREATMENT AND OUTCOME- Minimally invasive intracranial procedures were achieved by use of an endoscope to aid in lesion biopsy in a dog and a cat with neoplasia and complete lesion removal in 1 dog with a dermoid cyst. No obvious morbidity from the use of the endoscope was observed. Rapid recovery from surgery was seen in all 3 animals, and hospitalization times were a few days. CLINICAL RELEVANCE- In human and veterinary neurosurgery, minimally invasive surgical approaches for diagnosis and treatment are gaining in popularity. Minimally invasive techniques are used to achieve a decrease in surgical time, minimize brain exposure, and decrease postoperative recovery times. Keyhole and minimally invasive approaches require some degree of dexterity and knowledge of where the endoscope is in a 3-dimensional orientation and its relationship to the topography of an anatomic region. Anticipation of complications should allow for potential conversion to an open craniotomy. Use of the endoscope in minimally invasive procedures is associated with a steep learning curve to understand orientation, topography, and normal versus abnormal anatomy.