the role of endoscopic third ventriculostomy in the treatment of communicating hydrocephalus

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SEAN J. NAGEL ET AL. INVASIVE REEVALUATION FOR EPILEPSY

tive epilepsy surgery: the multicenter study. Neu-rology 65:912-918, 2005.

1. Tigaran S, Cascino GD, McClelland RL, So EL,Marsh WR: Acute postoperative seizures after fron-tal lobe cortical resection for intractable partial epi-lepsy. Epilepsia 44:831-835, 2003.

2. Van Gompel JJ, Worrell GA, Bell ML, Patrick TA,
Cascino GD, Raffel C, Marsh WR, Meyer FB: Intra-cranial electroencephalography with subdural grid a
Leonardo Rangel-Castilla, Sean Barber, Y

few reports that evaluate the role of ETV in

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electrodes: techniques, complications, and out-comes. Neurosurgery 63:498-505, 2008.

3. Wyler AR, Hermann BP, Richey ET: Results of reop-eration for failed epilepsy surgery. J Neurosurg 71:815-819, 1989.

onflict of interest statement: The authors declare that the
rticle content was composed in the absence of any A
i Jonathan Zhang

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ommercial or financial relationships that could beonstrued as a potential conflict of interest.

eceived 20 October 2010; accepted 23 June 2011

itation: World Neurosurg. (2012) 77, 3/4:548-555.OI: 10.1016/j.wneu.2011.06.037

ournal homepage: www.WORLDNEUROSURGERY.org

vailable online: www.sciencedirect.com

878-8750/$ - see front matter © 2012 Elsevier Inc.
ll rights reserved.
The Role of Endoscopic Third Ventriculostomy in the Treatment ofCommunicating Hydrocephalus

INTRODUCTION

Endoscopic third ventriculostomy (ETV)has become the treatment of choice in themanagement of obstructive hydrocepha-lus (HCP) due to its low risk and highsuccess rates (70%– 80%) (13, 14, 16, 21,23–26, 31, 36, 38). Endoscopic third ven-triculostomy bypasses the site of obstruc-tion in obstructive HCP and restores nor-mal physiologic cerebrospinal fluid (CSF)circulation. The role of ETV in communi-cating HCP is still unknown. There are

Key words� Communicating hydrocephalus� Endoscopic third ventriculostomy� Endoscopy

Abbreviations and AcronymsCSF: Cerebrospinal fluidETV: Endoscopic third ventriculostomyFIESTA: Fast imaging employing steady stateacquisitionHCP: HydrocephalusINPH: Idiopathic normal pressure hydrocephalusMRI: Magnetic resonance imagingNPH: Normal pressure hydrocephalusVP: Ventriculoperitoneal

Department of Neurosurgery, The MethodistNeurological Institute, Houston, Texas, USA

To whom correspondence should be addressed:Leonardo Rangel-Castilla, M.D.[E-mail: [email protected]]

Citation: World Neurosurg. (2012) 77, 3/4:555-560.DOI: 10.1016/j.wneu.2011.06.038

Journal homepage: www.WORLDNEUROSURGERY.org

Available online: www.sciencedirect.com

1878-8750/$ - see front matter © 2012 Elsevier Inc.All rights reserved.

econdary communicating HCP (post-eningitis and posthemorrhagic) and

ormal pressure HCP (NPH), reporting auccessful rate of 50% to 70% and 45% to2%, respectively (1, 5, 7, 11, 18, 20, 21,2). In the present study, we retrospec-ively reviewed the indications for ETVnd outcome after the procedure in a se-ies of 36 patients with communicating

� OBJECTIVE: To elucidate the role ofpatients with secondary and idiopathi

� METHODS: A series of 36 patientsomen) were treated by ETV betwee

atients age ranged from 19 to 81 yearf 6 to 36 months (mean 9.2 months). Thatients with secondary communicatormal pressure HCP. Sixteen (44.4%)eritoneal shunt placement that prese

RESULTS: The etiology of secondameningitis, trauma, neoplasm, and othein some patients. The outcome of Epatients (75%). A Kaplan-Meier analysof ETVs in secondary communicating H0.83, 0.8, and 0.77, respectively; in thewas 0.83 initially and became stablesuccessful proportion of ETV in commuof follow-up was 0.97, 0.83, 0.78, and

� CONCLUSIONS: ETV is a good ocommunicating HCP, normal pressuretriculoperitoneal shunts. The indicatcommunicating HCP needs further stu

ETHODS

hirty-six patients underwent ETV for thereatment of communicating HCP at our in-titution between November 2007 and Feb-uary 2010. The patient population con-isted of 15 women and 21 men with a meange of 52 years (range 19 – 81 years). Pre-enting symptoms included headaches in

oscopic third ventriculostomy (ETV) inmmunicating hydrocephalus (HCP).

communicating HCP (21 men and 15vember 2007 and February 2010. The(mean 52 years), and had a follow-uptients were divided into a group of 29

HCP and a group of 7 patients withe patients had a previous ventriculo-with shunt malfunction.

CP was subarachnoid hemorrhage,tiology was not possible to determine

was considered successful in 27/36vealed that the successful proportiont 0.5, 1, and 3 months of follow-up waspathic normal pressure HCP group it.66 after the first month. Overall, theting HCP was at 0, 0.5, 1, and 3 months

in the management of secondary, and replacing malfunctioning ven-of ETV as a first-line treatment inowever, results are promising.

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LEONARDO RANGEL-CASTILLA ET AL. ENDOSCOPIC THIRD VENTRICULOSTOMY FOR COMMUNICATING HYDROCEPHALUS

Table 1. Patient Information Regarding the 36 Patients Treated for Communicating Hydrocephalus with Endoscopic ThirdVentriculostomy (ETV)

Age(years) Sex

Follow-upPeriod

(months) Etiology Comorbidities

Presence of VPShunt at Time

of ETV

VP ShuntRemoved atTime of ETV Outcome

SignificantPostoperative

Events

78 F 6 INPH HTN, osteoporosis, GERD No — Successful

62 M 8 INPH DM2, HTN, hepatitis C Yes Yes Successful

76 M 6 INPH HTN No — Unsuccessful VP shunt placed

75 F 6 INPH COPD No — Successful

81 M 8 INPH COPD, posterior fossa meningioma,HTN

No — Unsuccessful VP shunt placed

77 M 6 INPH SDH Yes No Successful

73 F 8 INPH DM2, CKD, HTN No — Successful

63 F 33 SAH HTN, respiratory failure No — Unsuccessful VP shunt placed

35 F 6 SAH HTN No — Successful

69 M 6 SAH HTN No — Successful

55 F 6 SAH HTN, CHF No — Successful

45 M 6 SAH No — Successful

39 F 8 SAH No — Successful

58 F 6 SAH DM2 No — Successful

29 M 9 SAH AVM Yes Yes Unsuccessful VP shunt placed

60 F 6 stroke Yes Yes Successful

62 M 36 stroke HTN No — Successful

42 M 9 stroke Diverticulitis, peritonitis No — Successful

19 M 6 head trauma No — Successful

29 F 6 head trauma Yes Yes Successful

24 M 6 Chiari II Retroperitoneal abscess Yes No Unsuccessful VP shunt placed

28 M 6 Chiari II Yes No Unsuccessful VP shunt placed

37 F 22 neoplasm Hypothyroidism Yes No Unsuccessful VP shunt placed

43 M 10 neoplasm HIV/AIDS No — Unsuccessful Died 2/2 HIV/AIDS

47 M 7 meningitis Hepatitis B, HIV No — Successful

55 M 6 neurosarcoidosis DM2, HTN, seizure disorder No — Successful

66 M 6 IVH SDH Yes Yes Successful

28 M 6 unknown CP-angle cyst Yes No Successful

49 F 21 unknown Carpal tunnel, h/o spinal fusion Yes Yes Successful

31 M 6 unknown ESRD, SDH Yes Yes Successful

79 F 8 unknown SDH, atrial fibrillation, Parkinson’s No — Unsuccessful Died 2/2 MCA infarct

67 M 6 unknown SDH Yes Yes Successful

48 F 6 unknown Yes Yes Successful

76 M 6 unknown HTN, depression Yes Yes Successful

42 F 8 unknown Achondroplasia Yes Yes Successful

35 M 7 unknown No — Successful

M, male; F, female; INPH, idiopathic normal pressure hydrocephalus; SAH, subarachnoid hemorrhage; IVH, intraventricular hemorrhage; HTN, hypertension; GERD, gastroesophageal refluxdisease; DM2, diabetes mellitus type 2; COPD, chronic obstructive pulmonary disease; SDH, subdural hematoma; CKD, chronic kidney disease; CHF, congestive heart failure; AVM,arteriovenous malformation; HIV, human immunodeficiency virus; AIDS, acquired immune deficiency syndrome; CP-angle, cerebellopontine angle; ESRD, end-stage renal disease; h/o, history
of; VP shunt, ventriculoperitoneal shunt; MCA, middle cerebral artery; 2/2, secondary to.
556 www.SCIENCEDIRECT.com WORLD NEUROSURGERY, DOI:10.1016/j.wneu.2011.06.038

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patients, lethargy in 10 patients, cognitivedeficits or confusion in 10 patients, urinaryincontinence in 8 patients, seizures in 2 pa-tients, altered mental status in 2 patients,emesis in 2 patients, double vision in 1 pa-tient, fever in 1 patient, dizziness in 1 pa-tient, and tussive syncope in 1 patient. Somepatients presented with more than one symp-tom. A summary of patient information isshown in Table 1. The diagnosis of commu-

icating HCP was made primarily throughomputed tomography and/or magnetic res-nance imaging (MRI). The MRI study in-luded thin slice (3 mm) sagittal T2-weightedmages and fast imaging employing steadytate acquisition (FIESTA) protocol to evalu-te the cerebral aqueduct and fourth ventricleutlets. The study revealed a patent cerebralqueduct and fourth ventricle outlets in all 36atients. In the majority of patients, aqueduc-

al patency was also confirmed intraopera-ively with endoscopic direct visualization. In-lusion criteria for the study included: 1)resence of clinical signs or symptoms ofCP; 2) evidence of HCP with enlarged ventri-

les on neuroimaging; and 3) evidence of nontraventricular or aqueductal obstruction on

RI with the FIESTA protocol and/or intraop-rative direct visualization.

ETVs were performed as the initial proce-dure in 20 patients (55.4%). Sixteen patients(44.4%) had a history of one or more previoussurgical interventions for HCP, including ven-triculoperitoneal (VP) shunt in 14 patients and

Figure 1. Graph of a Kaplan-Meier ssuccessful rate after endoscopic thwith secondary communicating hydpressure hydrocephalus (INPH).

ventriculoatrial shunt in 2 patients.


The patients were divided in tworoups based on the preoperative diagno-is. The first group consisted of 29 pa-ients with secondary communicating

CP due to a variety of etiologies. Theecond group consisted of seven patientsith NPH (defined as primary communi-

ating HCP with normal CSF pressures onumbar puncture in the absence of intra-ranial lesions) (Table 1).

Endoscopic third ventriculostomy was per-ormed with a freehand standard method us-ng a rigid neuroendoscope (Aesculap, Inc.

l curve illustrating the overallntriculostomy (ETV) in patientshalus (SCH) and idiopathic normal

Figure 2. Graph of the Kaplan-Meiesuccessful rate of endoscopic thir
communicating hydrocephalus.

Center Valley, Pennsylvania, USA] or Karltorz Endoskope [Tuttlingen, Germany]) inll 36 patients. The endoscopic surgical tech-ique has been previously described (36). Af-

er performing the ETV, the Liliequist andrachnoid membranes were carefully in-pected, with direct confirmation of cerebralqueduct patency performed in some of theatients. Outcome was evaluated based on theata collected at the last follow-up clinic visit.he follow-up period ranged from 6 to 36onths (mean 9.2 months). Treatment suc-

ess was determined by clinical improvementf symptoms, radiologic evidence of no HCP,nd the lack of need for a shunt placementfter ETV.

ESULTS

here were no complications from the pro-edure. Two patients died in the follow-uperiod; one patient of the NPH group diedf a middle cerebral artery infarct and oneatient died of complications of advanceduman immunodeficiency virus/acquired

mmune deficiency syndrome at 6 and 4onths after the endoscopic procedure, re-

pectively. Neither death was technically re-ated to the ETV.

The causes of HCP in the 29 patients withecondary communicating HCP includedpontaneous subarachnoid hemorrhage in

patients, diffuse intracranial neoplasmsn 3 patients, stroke in 3 patients, head in-ury in 2 patients, Chiari malformation type

ival curve showing the overallriculostomy (ETV) in patients with

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II in 2 patients, histoplasma meningitis in 1patient, neurosarcoidosis in 1 patient, andintraparenchymal/intraventricular hemor-rhage in 1 patient. Eight patients had a pre-vious VP shunt and presented with VP shuntmalfunction. In these eight patients the un-derlying etiology or original cause of sec-ondary HCP was unknown and not possibleto determine.

The outcome of ETV was considered suc-cessful in 27/36 patients (75%). The major-ity of failed ETVs were seen in patients withidiopathic normal pressure HCP (INPH),subarachnoid hemorrhage, diffuse intra-cranial neoplasm, and Chiari malformationtype II as underlying etiologies for HCP (Ta-ble 1). A Kaplan-Meier analysis revealedthat the successful proportion of ETVs inthe INPH group was 0.83 initially and be-came stable at 0.66 after the first month(Figure 1). The successful proportion ofETVs in the secondary communicating HCPgroup at 0.5, 1, and 3 months of follow-upwas 0.83, 0.8, and 0.77, respectively (Figure1). Good clinical outcome in the NPH groupwas considered when symptoms related togait imbalance and incontinence disap-peared or improved, or were at least satis-factory for the patient. If this was not thecase, it was considered an unsuccessful ETVand a VP shunt was subsequently placed.The successful proportion of ETVs in boththe INPH and secondary communicatingHCP groups combined at 0, 0.5,1, and 3months of follow-up was 0.97, 0.83, 0.78,and 0.75, respectively (Figure 2).

Figure 3. Typical radiographic evolution of a patiecommunicating hydrocephalus (e.g., spontaneouhemorrhage). (A) Initial computed tomography (Csubarachnoid hemorrhage occupying the basal c
showing hydrocephalus 8 days after the initial hemorr
558 www.SCIENCEDIRECT.com

euroendoscopic Findingsithin the lateral ventricle we located the

oramen of Monro and its related neurovas-ular structures. Through the foramen ofonro, we reached the third ventricle. The

nterior and posterior portions of the thirdentricle were explored. In all the patients inhom the cerebral aqueduct was feasible tobserve, it was found to be patent and had aormal appearance. An ETV and Liliequistembranostomy were performed next. All

atients in the secondary communicatingCP group had a very firm and thick Lilieq-

ist membrane. Moderate-to-severe adhe-ive arachnoiditis and adhesion bands be-ween the clivus and basilar artery were alsoeen. In case the etiology of HCP was un-nown, biopsies were taken with biopsyorceps from the free edges of the stomand/or arachnoid membranes. This was thease for two patients in whom biopsy re-ults revealed neurosarcoidosis and Histo-lasma capsulatum.

entriculoperitoneal Shunt Independencend Need for New Shunt Placement

total of 16 patients had a previous VPhunt—14 from the secondary communi-ating HCP group and 2 from the NPHroup. Fifteen patients presented withhunt malfunction. One patient, from thePH group, presented with chronic sub-ural hematoma due to shunt overdrainage.n ETV was offered to these patients as anlternative. Ventriculoperitoneal shunt was

h secondaryarachnoidowing acutes. (B) CT scan

the patient underwentdays later after the enHowever, the patient’s6 weeks later after the

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WORLD NEUROSURGE

emoved from all the patients at the timehat ETV was performed. Seven patients19.44%) required a new VP shunt afterTV, five from the secondary communicat-

ng HCP group and two from the NPHroup. The need for a new VP shunt was due

o stagnant rehabilitation course, failure ofreoperative symptoms to resolve to a satis-

actory degree, and worsening HCP on fol-ow-up imaging. Of the five patients fromhe secondary communicating HCP groupequiring a VP shunt, subarachnoid hemor-hage was the initial diagnosis in two pa-ients, Chiari II malformation in two pa-ients, and intracerebral neoplasm in oneatient. The mean time from ETV to place-ent of a VP shunt in those seven patients

equiring a post-ETV VP shunt was 0.64onths (standard deviation 0.28 months).

ISCUSSION

ndoscopic third ventriculostomy is a safend minimally invasive procedure that haseen used routinely since the early 90s in

he treatment of many types of HCP. Theost common indication is obstructiveCP (e.g., aqueductal stenosis, fourth ven-

ricular outlet obstruction). It has not yeteen proved as an alternative in patientsith nonobstructive HCP. CommunicatingCP has not been scientifically established

s an indication for ETV. Previous reports oferies have retrospectively investigated theenefit of ETV in communicating HCP witharying results (5, 7, 11, 17–20, 22, 33).

scopic third ventriculostomy. (C) CT scan 5pic procedure revealing dilated ventricle.al condition improved remarkably. (D) CT scanscopic procedure showing normal size

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All the procedures were performed with arigid endoscope. However, a flexible neu-roendoscope would have been more usefulin exploring the cerebral aqueduct, thefourth ventricle, and the basal cisterns, aswe have shown in previous works (27, 34,35, 37). The steerable properties of theflexible neuroendoscope allow for a betterexploration of the ventricular system andsubarachnoid space with less trauma todelicate structures including the fornices,cerebral aqueduct, and the contents of thebasal cisterns such as arteries and cranialnerves (15, 37, 38). However, the flexibleneuroendoscope has not been adopted yetinto the daily neurosurgical practice at ourinstitution.

Pathophysiology of SecondaryCommunicating HCPThe cause of secondary communicatingHCP is important in giving us a directiontoward its origin and pathophysiology.Based on the role of the basal subarachnoidspace in the CSF circulation and its vulner-ability to insults, two major mechanismshave been proposed (6, 7). First, subarach-noid hemorrhage, trauma, and meningitiscan cause basal subarachnoid adhesionsand scars that consequently reduce the in-tracranial compliance by different mecha-nisms (6, 28 –30). Second, this adhesive ob-struction of the basal cisterns causes a typeof extraventricular intracisternal obstruc-tion that also contributes to the develop-ment of HCP (7). Previous experimentalmodels have shown that adhesions of thebasal subarachnoid space have a strongerimpact in the development of HCP than anintraventricular obstruction, highlightingthe role of the basal cisterns in the develop-ment of HCP (12). Experimental animalstudies have confirmed the relationship be-tween the amplitude of intraventricularpulse pressure and ventricular dilation (4).Other experiments have concluded that anyprocess interfering with the expansion ofthe arteries in the basal subarachnoid spacemay cause HCP (3, 6). However, there areother aspects that need to be clarified, suchas the normal-sized fourth ventricle, whichis commonly seen in nonobstructive HCP.

Most of the significant features of sec-ondary communicating HCP can be ex-plained by increased transmantle pulsatilestress affecting the brain, CSF spaces, and
vascular system. The hydrodynamics of f

hronic obstructive HCP is similar to that ofhronic communicating HCP, despite theifferent origin (6). Both types of chronicCP have in common the breakdown of theindkessel effect, with significant in-

reased pulsations of the brain capillaries.n summary, communicating HCP isaused by the combination of decreased in-racranial compliance and obstruction ofhe bulk flow of CSF at the level of the basalubarachnoid space (5–7).

ndoscopic Third Ventriculostomy inecondary Communicating HCPifferently from obstructive HCP, where

he treatment is aimed at removing or by-assing the obstruction, the primary goal inhronic communicating HCP is to restorehe intracranial compliance, either with aP shunt or an ETV. After CSF diversionith a VP shunt, the cortical veins will di-

ate. This venous dilation decreases the vas-ulature resistance and increases the cere-ral blood flow and perfusion pressure.imilar physiologic changes occur after anTV. After opening the ventricle into theasal subarachnoid space there is an in-rease expulsion of ventricular CSF duringystole, thus reducing the intraventricularulse pressure, the transmantle pulsatiletress, and the ventricular size. As a conse-uence, the subarachnoid spaces and theirontents expand including the corticaleins, thus restoring intracranial compli-nce, cerebral blood flow, and perfusionressure. Ventriculoperitoneal shunt andTV would theoretically increase intracra-ial compliance and decrease the trans-antle pulsatile stress, thereby reducing

he resistance to CSF reabsorption. Endo-copic third ventriculostomy offers an alter-ative treatment to shunting. It can be used

o replace a malfunctioning VP shunt orhen a child with a VP shunt grows and the

ubarachnoid space is well developed (10,6). In our group of patients we were able toeplace the malfunctioning VP shunt withn ETV in 12 (75%) without the need fornother VP shunt, at a mean follow-up pe-iod of 9.2 months. However, chronic com-

unicating HCP is a dynamic process andhere are reports of sudden deteriorationfter closure of the stoma or even mild headnjury (2), and patients should be closely
ollowed clinically (Figure 3). i

ndoscopic Third Ventriculostomy inormal Pressure HCPome physiopathologic considerationsuggest that selected patients with NPHould benefit from ETV. In normal condi-ions, the brain parenchyma acts as a vis-oelastic tissue able to diffuse the CSF pres-ure (8). In patients with NPH, this brainlasticity is lost due to multiple factors, in-luding an insufficient transcortical sub-rachnoid space and fibrosis meningitishat decrease the CSF absorption (9), as wells small periventricular ischemic lesionshat weaken the cerebral ventricles (1). Fen-stration of the floor of the third ventricle byn ETV results in a decrease in the intraven-ricular pressure, consequently increasingerebral blood flow and perfusion pressure5). Transmission of the pressure wavehrough the stoma could restore CSF dy-amics. Intraoperatively, after the ETV waserformed, we observed an increased CSFow from the ventricle into the basal cis-

erns, indicated by pulsation of the floor ofhe third ventricle and motion of the freedges of the stoma. Our overall success ratef 66% for ETV in NPH is very similar tother studies. Gangemi et al. (5) reported aostoperative clinical improvement of 72%

n a group of 25 patients with NPH whonderwent ETV. Mitchell and Mathew (20)eported improvement in 75% of their pa-ients with NPH after ETV. They suggestedhat this procedure may increase periven-ricular blood flow, especially in the thirdentricle. Meier et al. (17, 19) demonstratedhat patients with NPH who underwent ETVad a better late outcome and a higher un-erdrainage rate when compared with pa-

ients with NPH who were shunted.

ONCLUSIONS

nderstanding the pathophysiology ofommunicating HCP, the theory of de-reased cerebral compliance, and the con-ept of extraventricular intracisternal ob-truction is crucial in selecting the adequateurgical procedure to treat this condition.imilar to other studies, we observed thatTV is a good option in the management ofecondary communicating HCP and NPH.he indications for performing an ETV as arst-line treatment in communicating HCPeeds to be further studied; however, re-ults from retrospective studies are promis-
ng. Endoscopic third ventriculostomy

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should be considered an option in replacingmalfunctioning VP shunts and allowing pa-tients to be shunt independent.

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onflict of interest statement: The authors declare that therticle content was composed in the absence of anyommercial or financial relationships that could beonstrued as a potential conflict of interest.

eceived 15 February 2011; accepted 23 June 2011

itation: World Neurosurg. (2012) 77, 3/4:555-560.OI: 10.1016/j.wneu.2011.06.038

ournal homepage: www.WORLDNEUROSURGERY.org

vailable online: www.sciencedirect.com

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ll rights reserved.
RY, DOI:10.1016/j.wneu.2011.06.038



the role of endoscopic third ventriculostomy in the treatment of communicating hydrocephalus

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