**6. Complications**

neuroendoscopic approach presents a difficulty when the anatomical landmarks are distorted

Tectal and pineal tumors presenting with acute hydrocephalus also present an indication for tumor biopsy and ETV [38]. The management of these tumors depending on histology is combined open surgery and radiotherapy or chemotherapy. In the presence of obstructive hydrocephalus, neuroendoscopy presents an opportunity for the long term relieving the hydrocephalus and adequate tumor biopsy for determining the management. Long-term con-

In posterior fossa tumors, preoperative hydrocephalus can be managed with external ventricular drainage as well as ETV [40–42]. Postoperative hydrocephalus in posterior fossa tumors presents a major problem in these patients. In posterior fossa tumors, about 36% of patients need a CSF diversion surgery postoperatively [43]. The outcomes of ETV in postoperative hydrocephalus are about as good as shunting; however, failure happens earlier than VP shunts [44]. It is proven that ETV performed prior to surgery reduces significantly the incidence of postoperative hydrocephalus although it does not prevent hydrocephalus in all cases. It does however prevent acute postoperative hydrocephalus due to cerebellar swelling and presents a cleaner and more physiologic method compared to external ventricular drainage [41]. The effectiveness of ETV is also demonstrated in brain stem gliomas causing hydrocephalus [45]. The treatment of choice for suprasellar arachnoid cysts is endoscopic fenestration of the cyst into ventricular system combined with ETV (cystoventriculocisternostomy). Several series demonstrated cyst and hydrocephalus regression with this technique [46, 47]. Cystostomy and ETV might also be indicated in some pineal cysts and quadrigeminal cysts presented

Contrary to obstructive hydrocephalus, indications of communicating hydrocephalus are controversial [50]. There are successful series of ETV on normal pressure hydrocephalus in literature with improvement rate after ETV up to 69% [51]. However, the etiology of this success is not yet well defined. Some authors argue that the third ventriculostomy relieves

In patients with Chiari malformation type I with concomitant hydrocephalus, ETV is proven to be beneficial [53]. In these patients relief of symptoms, ascent of the tonsils, regression of hydrocephalus, and syringomyelia are seen after ETV [54, 55]. The established treatment for these patients is suboccipital craniectomy and duraplasty combined with CSF diversion surgery. In these selected cases, ETV proves to be successful meaning that the cure might be achieved in a less invasive and less complicated manner. As for Chiari malformation type II, the overall success for patients with concomitant meningomyelocele and hydrocephalus is up to 72% [56]. In these patients, ETV presents a safe and an effective way to deal with hydro-

Success rates of EVT vary from 50–90% in literature [52, 58]. Good outcomes are highest with up to about 90% in obstructive hydrocephalus series that includes aqueductal stenosis and

trol of hydrocephalus is possible with ETV in tectal plate tumors [39].

by the growth of the tumor.

118 Hydrocephalus: Water on the Brain

with hydrocephalus [48, 49].

**5. Outcomes**

periventricular tissue stress improving the perfusion [52].

cephalus and long-term shunt independence [57].

The overall complication rate of ETV series is found to be 8.5% by Bouras and Sgouros [69]. The complication rates varied between 0 and 31.2%. Overall permanent morbidity rate was 2.38%, and the mortality rate was found 0.28%. Complications can be categorized as intraoperative, early postoperative, and late postoperative.

**Acknowledgements**

**Conflict of interest**

**Thanks**

**Author details**

Tugrul Cem Unal<sup>1</sup>

Turkey

**References**

We wish to acknowledge Dr. Altay Sencer of the Department of Neurosurgery, Istanbul

Endoscopic Third Ventriculostomy

121

http://dx.doi.org/10.5772/intechopen.75394

University, Istanbul Faculty of Medicine, Istanbul, for his assistance.

Authors declare that they have no conflict of interest.

We wish to thank Cristina Brinza for her illustrations.

\* and Aydin Aydoseli<sup>2</sup>

1 Department of Neurosurgery, Tunceli State Hospital, Tunceli, Turkey

2 Department of Neurosurgery, Istanbul University, Istanbul Faculty of Medicine, Istanbul,

[1] Sufianov A, Sufianova G, Iakimov I. Neuroendoscopic procedures in achievement of shunt independence: Outcome analysis of 28 patients with shunt malfunction. Minimally

[2] Dandy WE. An operative procedure for hydrocephalus. Bulletin of the Johns Hopkins

[3] Mixter WJ. Ventriculoscopy and puncture of the floor of the third ventricle. The Boston

[4] Putnam TJ. Treatment of hydrocephalus by endoscopic coagulation of the choroid plexus. Description of a new instrument and preliminary report of results. The New

[5] Scarff JE. Treatment of obstructive hydrocephalus by puncture of the lamina terminalis

and floor of the third ventricle. Journal of Neurosurgery. 1951;**8**:204-2013

\*Address all correspondence to: tugrulcem@gmail.com

Invasive Neurosurgery. 2008;**51**:158-164

Medical and Surgical Journal. 1923;**188**:277-278

England Journal of Medicine. 1934;**210**:1373-1376

Hospital. 1922;**33**:189-190

Neurovascular injury and bradycardia are the most common intraoperative complications. Various authors reported arterial and venous bleeding during the procedure [59, 63, 70]. Considerable intraoperative bleeding is reported almost 3.7% of the procedures, and about 4.2% of the ETVs is abandoned due to hemorrhage. Many authors reported different rates of intraoperative bleeding. But severe bleeding rates are low as 0.6%, and the rate of the most frightening intraoperative complication of ETV—basilar artery rupture—is as low as 0.2%. Pseudoaneurysm formation in the basilar tip after basilar injury is reported. Bradycardia is reported up to 41% during ETV [71]. A proposed mechanism for bradycardia is the generation of Cushing reflex due to irrigation and stimulation of hypothalamic nuclei. Even cardiac arrest is reported during an ETV performed for posthemorrhagic hydrocephalus [72].

Immediate preoperative complications include postoperative hemorrhagic complications like subdural hematoma, intraventricular hemorrhage, intracerebral hematoma, and epidural hematoma. The total rate of hemorrhagic complications is about 0.81%, and subdural hematoma being the most common hemorrhage [69]. A large corticotomy and sudden drainage of CSF are possible risk factors for development of subdural hematoma. Increased ICP of the subdural space also seems to be the cause of subdural hygromas. Central nervous system infections are one of the severe early postoperative complications. Meningitis or ventriculitis is recorded in 1.81% of the patients. Cerebrospinal fluid leak due to increased subdural pressure from corticotomy is also a postoperative concern as it can lead to CNS infections. Electrolyte and hormonal imbalances are reported in the literature. Systemic complications including syndrome of inappropriate antidiuretic hormone secretion, diabetes insipidus, and secondary amenorrhea are also found to be complications.

The most important late complication is the failure of the ETV. Sudden deterioration and death are reported in the literature, but it occurs rarely [73, 74]. As the risk of epilepsy being very low for this procedure, seizures are still a possible complication developing after ETV. Neurological morbidity is a possibility although rare with a total rate of 1.44%. Memory deficits may occur after ETV, and suggested hypothesis is fornix injury during the procedure. Fornix contusion is reported in ETV patients up to 16.4% [33]. Memory problems can be transient as well as permanent. Other than neuropsychiatric problems, hemiparesis, decreased consciousness, and gaze palsy are some of the rare neurological complications [69].
