In conclusion, endoscopic third ventriculostomy, as an alternative to conventional ventriculoperitoneal or ventriculoatrial shunting, is a firmly established treatment for hydrocephalus, and it has yielded a higher success rate with lower morbidity and mortality than earlier methods of third ventriculostomy. Results of endoscopic third ventriculostomy are most closely associated with the etiology of hydrocephalus encountered as well as with the clinical and radiographic features of the individual patient [23]. High success rates have been reported for patients with aqueduct stenosis. Lower success rates have been reported for patients with hydrocephalus from other causes, such as postinfection, posthemorrhage, or myelomeningocele, and for patients with previous ventricular shunt failure [8, 24]. Although endoscopy seems to be performed with ease in general, it can be difficult and hazardous in certain situations. Intraoperative complications due to injury to anatomical structures resulting from inappropriate surgical technique or inadequate knowledge of anatomy, and early or late postoperative complications such as infections, CSF fistula, pneumocephalus, subdural hematoma, or re-closure of an opened orifice will be discussed in the following chapters.