Endoscopic Assist for Pediatric Tumors, Vascular, and Hydrocephalus:...

Endoscopic-assist uses the endoscope to augment visualization during microscopic craniotomy, whereas endoscopic-controlled uses the endoscope as the sole visualization (e.g., transnasal pituitary).

A rigid endoscope holding arm is necessary for endoscopic-assist cases to free the surgeon's hands and maintain spatial awareness in the limited craniotomy field.

Rigid scopes are preferred over flexible scopes in endoscopic-assist settings due to superior optics and lower risk of damage during extraction.

Insertion and removal of the endoscope are the riskiest phases; the surgeon must watch the scope under the microscope rather than the endoscopic screen to avoid injury to the frontal lobe, olfactory nerves, optic chiasm, or carotid.

Spatial awareness is critical in endoscopic-assist because the surgeon cannot see behind the scope; structures posterior to the scope tip are invisible.

Angled rigid scopes (30° and 70°) allow visualization around corners and beneath structures (e.g., optic chiasm) that would otherwise require retraction or repositioning.

For sellar/suprasellar craniopharyngiomas, approach selection (transnasal vs. cranial) depends on patient age, sphenoid ossification, nares size, and pituitary function.

Endoscopic assist from a subfrontal or transciliary approach can reproduce the view obtained transnasally, allowing visualization beneath the optic chiasm and into the third ventricle.

Direct endoscopic visualization of the hypothalamic-capsule interface during craniopharyngioma resection reduces the risk of hypothalamic injury compared to blind pulling of the capsule.

Over the years, surgeons have become more conservative in managing the hypothalamic portion of craniopharyngiomas that extend into the third ventricle, often leaving capsule behind.

The transciliary eyebrow incision with small orbitotomy and zygomatic work provides a low corridor to the anterior cranial fossa, suitable for endoscopic-assist or endoscopic-controlled approaches.

Grant's series includes approximately 120 transciliary approaches to the anterior cranial fossa.

The transciliary approach allows access to the pituitary stalk for biopsy (e.g., for thickened stalk lesions such as germinoma, Langerhans cell histiocytosis, or lymphocytic hypophysitis) without moving the chiasm or carotid.

Endoscopic assist provides better illumination and magnification in deep corridors where the microscope's light and optics are limited.

The 0° endoscope is used initially for illumination and direct visualization, then 30° and 70° scopes are used to look around corners; higher angles require greater spatial awareness.

Grant does not routinely use endoscopic assist for primary shunt placement but uses it routinely for shunt revisions.

Future developments in 3D endoscope technology and augmented reality may improve spatial understanding and optics in endoscopic-assist surgery.

For shunt revisions in slit-ventricle patients, 1mm rigid endoscopes allow the surgeon to follow the old shunt tract, visualize the ventricle, and place a new catheter without dissecting into white matter.

Endoscopic assist for shunt revision avoids the need for image guidance (e.g., BrainLab, Stealth) by providing direct visualization along the old tract.

In endoscopic-assist cases, the rigid endoscope is used purely as an optical device, not for instrument passage.

Endoscope tips heat up during use and should not be placed directly against the carotid or other vascular structures to avoid thermal injury.

Grant does not use a sheath for endoscopic-assist cases (open craniotomy) but does use a sheath for endoscopic-controlled intraventricular cases to protect the cortex during insertion and removal.

The surgical field should be kept moist during endoscope insertion to prevent the scope from sticking to perforators or other structures.