Endoscopic third ventriculostomy

The ETV procedure is used as an alternative to a cerebral shunt[http://www.aboutkidshealth.ca/en/healthaz/ConditionsandDiseases/BrainandNervousSystemDisorders/Pages/Hydrocephalus-and-Treatment-Shunts-and-Endoscopic-Third-Ventriculostomy.aspx Hydrocephalus and Treatment: Shunts and Endoscopic Third Ventriculostomy], AboutKidsHealth.ca mainly to treat certain forms of noncommunicating obstructive hydrocephalus (such as aqueductal stenosis), but since the ETV was introduced as an accepted treatment modality the range of etiologies for which it is used has grown significantly. Whereas at first it was almost exclusively performed in patients with noncommunicating obstructive hydrocephalus (e.g. aqueductal stenosis or intracerebral tumor), in the present day patients with communicating obstructive hydrocephalus (e.g. post intracranial hemorrhage or post intracranial infection) also may be eligible for treatment by means of ETV.{{cn|date=January 2022}}

A major advantage of performing an endoscopic third ventriculostomy over placement of a cerebrospinal fluid shunt is the absence of an implanted foreign body. A shunt has risk of infection and failure for which subsequent surgery is needed. Complications of ETV include hemorrhage (the most severe being due to basilar artery rupture), injury to neural structures (e.g. hypothalamus, pituitary gland or fornix of the brain), and late sudden deterioration.{{cite journal |doi= 10.1016/j.wneu.2012.02.014|pmid= 22381818|title= Complications of endoscopic third ventriculostomy|journal=Journal of Neurosurgery|volume=79|issue=2 Supple|pages=e9–12|year=2013|last1=Bouras|first1=T.|last2=Sgouros|first2=S.}} Infection, hematoma, and cerebrospinal fluid leaks may present in the direct postoperative period.

Failure of the ETV occurs. This can be due to occlusion of the ventriculostomy (e.g. closure of the ventriculostomy, formation of subarachnoid membranes in the pontine cistern or other mechanisms). Although 60 - 90% of failures occur in the first few months after treatment, long-term failure also occurs (failures occurring after 7 years have been reported).{{Cite journal|title = Long-term results of endoscopic third ventriculostomy: an outcome analysis|journal = Journal of Neurosurgery|date = 2015-07-31|pages = 1456–1462|doi = 10.3171/2014.11.jns14414|pmid = 26230473|language = en|first1 = Sonja|last1 = Vulcu|first2 = Leonie|last2 = Eickele|first3 = Giuseppe|last3 = Cinalli|first4 = Wolfgang|last4 = Wagner|first5 = Joachim|last5 = Oertel|volume=123|issue = 6|doi-access = free}} In a very small subgroup of patients a complication of ETV can be rapid late deterioration.{{cite journal |doi= 10.3171/ped.2006.105.2.118|pmid= 16922073|title= Late rapid deterioration after endoscopic third ventriculostomy: additional cases and review of the literature.|journal=Journal of Neurosurgery|volume=105|issue=2 Supple|pages=118–26|year=2006|last1=Drake|first1=J.|last2=Chumas|first2=P.|last3=Kestle|first3=J.|last4=Pierre-Kahn|first4=A.|last5=Vinchon|first5=M.|last6=Brown|first6=J.|last7=Pollack|first7=I.F.|last8=Arai|first8=H. |s2cid= 41357365}} The mechanism is not clear.

When it is not possible to perform an ETV for different reasons, an alternative treatment is opening the lamina terminalis anterior to the third ventricle.{{cite journal |doi=10.3171/2010.6.JNS09491|pmid=20707616|title=Endoscopic transventricular third ventriculostomy through the lamina terminalis|journal=Journal of Neurosurgery|volume=113|issue=6|pages=1261–9|year=2010|last1=Oertel|first1=Joachim M. K.|last2=Vulcu|first2=Sonja|last3=Schroeder|first3=Henry W. S.|last4=Konerding|first4=Moritz A.|last5=Wagner|first5=Wolfgang|last6=Gaab|first6=Michael R.|s2cid=9327180}} The effectiveness of this approach is not certain.{{cite journal |doi=10.3171/2009.1.JNS0821|pmid=19284236|title=Efficacy of lamina terminalis fenestration in reducing shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage: A systematic review|journal=Journal of Neurosurgery|volume=111|issue=1|pages=147–54|year=2009|last1=Komotar|first1=Ricardo J.|last2=Hahn|first2=David K.|last3=Kim|first3=Grace H.|last4=Starke|first4=Robert M.|last5=Garrett|first5=Matthew C.|last6=Merkow|first6=Maxwell B.|last7=Otten|first7=Marc L.|last8=Sciacca|first8=Robert R.|author9-link=E. Sander Connolly|last9=Connolly|first9=E. Sander|s2cid=28475913}}

The surgical treatment options for hydrocephalus are, as previously mentioned, implantation of a cerebral shunt and ETV. Especially in the youngest age group (younger than two years of age) it remains uncertain what is the superior treatment modality. Currently, a large international, multicenter study is conducted to address this issue. Patients under the age of two, diagnosed with aqueductal stenosis without a history of preterm birth or other associated brain anomalies are being included (International Infant Hydrocephalus Study).{{Cite journal|title = The international infant hydrocephalus study: concept and rational|journal = Child's Nervous System|date = 2005-10-15|issn = 0256-7040|pages = 338–345|volume = 22|issue = 4|doi = 10.1007/s00381-005-1253-y|pmid = 16228238|language = en|first1 = S.|last1 = Sgouros|first2 = A. V.|last2 = Kulkharni|first3 = S.|last3 = Constantini| s2cid=25533719 }}{{cite journal |doi= 10.1016/j.wneu.2012.02.003|pmid= 22381849|title= Neuroendoscopy in the youngest age group.|journal=World Neurosurgery|volume=79|issue=2 Supple|pages=S23.e1–11|year=2013|last1=Constantini|first1=S.|last2=Sgouros|first2=S.|last3=Kulkarni|first3=A.}}

There is a discussion regarding the additional benefit of combining endoscopic third ventriculostomy with choroid plexus cauterization. This combined procedure is referred by the abbreviation "ETV/CPC" and has also been called the "Warf Procedure"{{cite web|title=Neurosurgeons challenged to eliminate all infant deaths from hydrocephalus|url=http://www.eurekalert.org/pub_releases/2016-01/luhs-nct011216.php|website=EurekAlert|accessdate=14 January 2016}} after Dr. Benjamin Warf. There have been research studies published about the experience of authors with this procedure. The lion's share of the data that show favorable results is reported on patients in Africa.{{cite journal |doi= 10.3171/2012.4.PEDS1253|pmid= 22747094

|title= Long-term outcome for endoscopic third ventriculostomy alone or in combination with choroid plexus cauterization for congenital aqueductal stenosis in African infants|journal=Journal of Neurosurgery. Pediatrics|volume=10|issue=2 |pages=108–11|year=2012|last1=Warf|first1=B.C.|last2=Tracy|first2=S.|last3=Mugamba|first3=J. |doi-access=}} More recent studies from research groups in Western countries also show that the combination of ETV with choroid plexus cauterization seems to be effective, safe, and durable,{{cite journal |doi= 10.3171/2014.7.PEDS14152|pmid= 25171723|title= Combined endoscopic third ventriculostomy and choroid plexus cauterization as primary treatment for infant hydrocephalus: a prospective North American series|journal=Journal of Neurosurgery. Pediatrics|volume=14|issue=5 |pages=439–46|year=2014|last1=Stone|first1=S.S.|last2=Warf|first2=B.C. |doi-access=free}} and that predictions for success are similar to those of ETV alone.{{cite web|last1=Riva-Cambrin|first1=Jay|title=ETV+CPC Success and Evolving Indications over Time: A Prospective HCRN Study|url=http://hcrn.org/hcrn-presents-preliminary-data-on-new-procedure/|website=Hydrocephalus Clinical Research Network|accessdate=7 March 2016}} The degree of choroid plexus cauterization in infants might be dependent on the experience of the neurosurgeon (learning curve) and thus surgeons training might improve results.{{cite journal |doi=10.3171/2014.6.PEDS13492|pmid=24995823|title=Endoscopic third ventriculostomy and choroid plexus cauterization in infants with hydrocephalus: a retrospective Hydrocephalus Clinical Research Network study|journal=Journal of Neurosurgery. Pediatrics|volume=14|issue=3|pages=224–9|year=2014|last1=Kulkarni|first1=A.V.|last2=Riva-Cambrin|first2=J.|last3=Browd|first3=S.R.|last4=Drake|first4=J.M.|last5=Holubkov|first5=R.|last6=Kestle|first6=J.R.|last7=Limbrick|first7=D.D.|last8=Rozzelle|first8=C.J.|last9=Simon|first9=T.D.|last10=Tamber|first10=M.S.|last11=Wellons|first11=J.C.3rd.|last12=Whitehead|first12=W.E.|last13=Hydrocephalus Clinical Research Network. |doi-access=free}} The ETV/CPC procedure is now being performed in a number of hospitals in US and Canadian cities, including Seattle, Washington; Houston, Texas; Calgary, Alberta; Toronto, Ontario; Salt Lake City, Utah; and Boston, Massachusetts.{{cite news|last1=Ruparell|first1=Asha|title=New neurosurgery saves lives in Calgary by treating hydrocephalus, 'water in the brain'|url=http://globalnews.ca/news/2719800/new-neurosurgery-saves-lives-in-calgary-by-treating-hydrocephalus-water-in-the-brain/|accessdate=25 May 2016|work=Global News}}

The chances of success of treatment of a pediatric patient can be calculated using the ETV success score (ETVSS).{{cite journal |doi=10.1016/j.jpeds.2009.02.048|pmid=19446842|title=Endoscopic third ventriculostomy in the treatment of childhood hydrocephalus|journal=Journal of Pediatrics|volume=155|issue=2|pages=254–9|year=2009|last1=Kulkarni|first1=A.V.|last2=Drake|first2=J.M.|last3=Mallucci|first3=C.L.|last4=Sgouros|first4=S.|last5=Roth|first5=J.|last6=Constantini|first6=S.|last7=Canadian Pediatric Neurosurgery Study Group}}{{Cite journal|title = Endoscopic third ventriculostomy in the treatment of childhood hydrocephalus: validation of a success score that predicts long-term outcome|journal = Journal of Neurosurgery: Pediatrics|date = 2011-11-01|issn = 1933-0707|pages = 489–493|volume = 8|issue = 5|doi = 10.3171/2011.8.PEDS1166|pmid = 22044375|first1 = Andrew J.|last1 = Durnford|first2 = Fenella J.|last2 = Kirkham|first3 = Nijaguna|last3 = Mathad|first4 = Owen C. E.|last4 = Sparrow}}{{Cite journal|title = An external validation of the ETVSS for both short-term and long-term predictive adequacy in 104 pediatric patients|journal = Child's Nervous System|date = 2013-05-05|issn = 0256-7040|pages = 1305–1311|volume = 29|issue = 8|doi = 10.1007/s00381-013-2122-8|pmid = 23644629|language = en|first1 = G. E.|last1 = Breimer|first2 = D. A.|last2 = Sival|first3 = M. G. J.|last3 = Brusse-Keizer|first4 = E. W.|last4 = Hoving| s2cid=24475766 }} The ETVSS is derived from patient age, etiology of hydrocephalus and history of previous cerebrospinal fluid shunt (e.g. ventriculo-peritoneal shunt). The percentage probability of ETV success = Age score + Etiology score + Previous shunt score. A two years old patient with hydrocephalus due to aqueductal stenosis, without previous shunt would have an 80% chance of success (40 for age + 30 for etiology + 10 for no previous shunt = 80).

ETVSS table

The ETVSS was derived and validated without the use of adult data and it has inadequate discriminative ability in mixed adult and pediatric populations.{{Cite journal|title = Predicting success of endoscopic third ventriculostomy: validation of the ETV Success Score in a mixed population of adult and pediatric patients.|journal = Journal of Neurosurgery|date = 2015-07-24|pages = 1447–1455|volume = 123|issue = 6|doi = 10.3171/2014.12.JNS141240|pmid = 26207604|language = en|first1 = M.|last1 = Labidi|first2 = P.|last2 = Lavoie|first3 = G.|last3 = Lapointe|first4 = D.|last4 = Obaid|first5 = A.G.|last5 = Weil|first6 = M.W.|last6 = Bojanowski|first7 = A.|last7 = Turmel|doi-access = free}}

After a patient gets readmitted with recurrent clinical and radiological symptomatology of hydrocephalus, it is unclear what the next step in treatment should be. Implantation of a cerebrospinal fluid shunt or repeat ETV. Data suggest that a second ETV might be worthwhile if implantation of cerebrospinal fluid shunt can be avoided.{{cite journal |doi= 10.1227/01.NEU.0000350228.08523.D1|pmid= 19687699|title= Long-term results of a second endoscopic third ventriculostomy in children: retrospective analysis of 40 cases.|journal=Neurosurgery|volume=65|issue=3|pages=539–47|year=2009|last1=Peretta|first1=P.|last2=Cinalli|first2=G.|last3=Spennato|first3=P.|last4=Ragazzi|first4=P.|last5=Rugierro|first5=C.|last6=Aliberti|first6=F.|last7=Carlino|first7=C.|last8=Cianciulli|first8=E. |s2cid= 22505364}}{{Cite journal|title = Reopening of an obstructed third ventriculostomy: long-term success and factors affecting outcome in 215 infants|journal = Journal of Neurosurgery: Pediatrics|date = 2015-02-06|pages = 399–405|volume = 15|issue = 4|doi = 10.3171/2014.10.peds14250|pmid = 25658247|language = en|first1 = Paul J.|last1 = Marano|first2 = Scellig S. D.|last2 = Stone|first3 = John|last3 = Mugamba|first4 = Peter|last4 = Ssenyonga|first5 = Ezra B.|last5 = Warf|first6 = Benjamin C.|last6 = Warf|doi-access = free}}

In most countries and neurosurgical centres, the ETV procedure is part of the basic neurosurgery training program. For the sake of teaching and practicing, various simulation models have been developed. Virtual reality simulators,{{cite journal |doi= 10.1016/j.wneu.2012.08.022|pmid= 23178917|title= Fundamentals of neurosurgery: virtual reality tasks for training and evaluation of technical skills.|journal=World Neurosurgery|volume=80|issue=5|pages=e9–19|year=2013|last1=Choudhury|first1=N.|last2=Gelinas-Phaneuf|first2=F.|last3=Delorme|first3=S.|last4=Del Maestro|first4=R. |s2cid= 3028199|url= https://nrc-publications.canada.ca/eng/view/accepted/?id=482c4848-9237-41e1-bb5d-d4de3928c82a}} and synthetic simulators.{{cite journal |doi= 10.3171/2014.9.PEDS1447|pmid= 25360853|title= Design and evaluation of a new synthetic brain simulator for endoscopic third ventriculostomy.|journal=Journal of Neurosurgery. Pediatrics|volume=15|issue=1|pages=82–8|year=2015|last1=Breimer|first1=G.E.|last2=Bodani|first2=V.|last3=Looi|first3=T.|last4=Drake|first4=J.M. |s2cid= 10586172|doi-access=free}}{{cite journal |doi=10.1055/s-0029-1246169|pmid= 20376746|title=Neuroendoscopic training: presentation of a new real simulator.|journal=Minimally Invasive Neurosurgery|volume=53|issue=1|pages=44–6|year=2010|last1=Zymberg|first1=S.|last2=Vaz-Guimaraes Filho|first2=F.|last3=Lyra|first3=M. |s2cid= 37521372}} This allows neurosurgical trainees to practice skills in a low-risk environment. Educators can select either a virtual reality simulator or a physical model for the training of residents, the selection should be based on educational objectives. Where training focused on anatomy and using anatomical landmarks for decision making may better be aided with virtual reality model, the focus on familiarizing the resident with endoscopic equipment and developing manual dexterity may be better learned on a physical model.{{cite journal|last1=Breimer|first1=Gerben E.|last2=Haji|first2=Faizal A.|last3=Bodani|first3=Vivek|last4=Cunningham|first4=Melissa S.|last5=Lopez-Rios|first5=Adriana-Lucia|last6=Okrainec|first6=Allan|last7=Drake|first7=James M.|title=Simulation-based Education for Endoscopic Third Ventriculostomy|journal=Operative Neurosurgery|volume=13|issue=1|date=June 2016|pages=89–95|doi=10.1227/NEU.0000000000001317|pmid=28931258}} The technical skill and competency of a trainee can be evaluated using the Neuro-Endoscopic Ventriculostomy Assessment Tool (NEVAT).{{Cite journal|title = Development and content validation of performance assessments for endoscopic third ventriculostomy|journal = Child's Nervous System|date = 2015-05-01|issn = 0256-7040|pages = 1247–1259|volume = 31|issue = 8|doi = 10.1007/s00381-015-2716-4|pmid = 25930722|language = en|first1 = Gerben E.|last1 = Breimer|first2 = Faizal A.|last2 = Haji|first3 = Eelco W.|last3 = Hoving|first4 = James M.|last4 = Drake| s2cid=24043065 }}

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• [http://www.medscape.com/viewarticle/520953_3 Video and more about the ETV procedure from an article on Medscape]

Category:Endoscopy

Category:Neurosurgical procedures

Category:Ventricular system