Result of Endoscopic Third Ventriculostomy for Hydrocephalus Caused by Cerebral Aqueductal Stenosis in Infant Patients

Abstract

Background Endoscopic third ventriculostomy (ETV) is one of the important management options for hydrocephalus, especially obstructive hydrocephalus. The result of ETV in different age and etiology is quite variable according to the different authors. The study was carried out to assess the success rate of ETV as a treatment for this type of hydrocephalus in infant age group.
Material and Methods The study was done prospectively on infants (age ≤ 12 months) admitted in the period from January 2009 to June 2013 suffering from obstructive hydrocephalus due to cerebral aqueductal stenosis (CAS). After making the diagnosis, we counseled the patient party about the probability of high failure rate of ETV in this age group and probable necessity of a second operation. With the informed consent, we performed ETV in these cases and followed up regularly in postoperative period. Control neuroimaging studies were done whenever needed (suspected failure of ETV and suspected stomal block).
Results Total 17 infants were studied. Average follow-up was 18.7 months. Twelve infants were between the age group of six and under six months while five were above six months to one year old. Fourteen (82.35%) out of 17 patients showed overall clinical improvement. Clinical improvement was seen in two (66.6%) infants aged 2 months or younger, three (75%) aged 2+ to 3 months, five (100%) aged 3+ to 6 months, and four (80%) aged 6+ months to 1 year. Two patients had bleeding during surgery. Three developed CSF leak through the burr hole. In one case (the patient's age was 2 months), the stoma was found blocked, and hydrocephalus returned 9 weeks after ETV. In two patients, in whom VP shunt was needed, “failed ETV” was obvious in early postoperative period. In this series, average ETV success score (ETVSS) was 52.35 (range: 40–70) and overall success rate was 82.35%. This indicates that ETVSS does not correlate with the outcome of ETV in infants with CAS.
Conclusion Outcome of ETV for hydrocephalus from CAS in infant is quite good and ETVSS does not correlate with the outcome.

Full text

Result of Endoscopic Third Ventriculostomy for
Hydrocephalus Caused by Cerebral Aqueductal
Stenosis in Infant Patients
Forhad H. Chowdhury1Mohammod R. Haque2Khandkar A. Kawsar2Mainul H. Sarker2
Abdul Fazal Mohammod M. Haque1
1Department of Neurosurger y, National Institute of Neurosciences
and Hospital, Sher-e-bangla Nagar, Dhaka, Bangladesh
2Department of Neurosurger y, Dhaka Medical College Hospital,
Dhaka, Bangladesh
Indian J Neurosurg
Address for correspondence Forhad Hossain Chowdhur y, FCPS,
Department of Neurosurgery, National Institute of Neurosciences and
Hospital, Sher-e-bangla Nagar, Dhaka 1207, Bangladesh
(e-mail: forhadchowdhury74@yahoo.com).
Keywords
►endoscopic third
ventriculostomy
►obstructive
hydrocephalus
►cerebral aqueductal
stenosis
►ETV success score
►results
Abstract Background Endoscopic third ventriculostomy (ETV) is one of the important management
options for hydrocephalus, especially obstructive hydrocephalus. The result of ETV in
different age and etiology is quite variable according to the different authors. The
study was carried out to assess the success rate of ETV as a treatment for this type of
hydrocephalus in infant age group.
Material and Methods Thestudywasdoneprospectivelyoninfants(age12
months) admitted in the period from January 2009 to June 2013 suffering from
obstructive hydrocephalus due to cerebral aqueductal stenosis (CAS). After making
the diagnosis, we counseled the patient party about the probability of high failure rate
of ETV in this age group and probable necessity of a second operation. With the
informed consent, we performed ETV in these cases and followed up regularly in
postoperative period. Control neuroimaging studies were done whenever needed
(suspected failure of ETV and suspected stomal block).
Results Total 17 infants were studied. Average follow-up was 18.7 months. Twelve
infants were between the age group of six and under six months while five were above
six months to one year old. Fourteen (82.35%) out of 17 patients showed overall
clinical improvement. Clinical improvement was seen in two (66.6%) infants aged 2
months or younger, three (75%) aged 2
þ
to 3 months, five (100%) aged 3
þ
to 6
months, and four (80%) aged 6
þ
months to 1 year. Two patients had bleeding during
surgery. Three developed CSF leak through the burr hole. In one case (the patient’s
age was 2 months), the stoma was found blocked, and hydrocephalus returned 9
weeks after ETV. In two patients, in whom VP shunt was needed, “failed ETV”was
obvious in early postoperative period. In this series, average ETV success score (ETVSS)
was 52.35 (range: 40–70) and overall success rate was 82.35%. This indicates that
ETVSS does not correlate with the outcome of ETV in infants with CAS.
Conclusion Outcome of ETV for hydrocephalus from CAS in infant is quite good and
ETVSS does not correlate with the outcome.
received
November 2, 2016
accepted
July 3, 2017
DOI https://doi.org/
10.1055/s-0037-1607053.
ISSN 2277-954X.
© Neurological Surgeons’Society of
India
THIEME
Original Article

Introduction
Themostcommontherapeuticoptionsusedtotreat
hydrocephalus (HCP) include ventriculoperitoneal (VP)
drainage and neuroendoscopic surgery. Although there are
pros and cons for each option, VP shunt techniques have
high complication rate (20–80%).1–3Endoscopic third
ventriculostomy (ETV) is well accepted for obstructive
hydrocephalus of various etiologies.4–10 It is considered as
a better alternative to shunt surgery in obstructive HCP.
Though some authors advocate ETV in patients of all
ages,1–3,11 others showed that patients younger than
1 year have a higher failure rate for ETVs compared with
older children.12 Therefore, we present our experience of
ETV in obstructive HCP caused by congenital cerebral
aqueductal stenosis (CAS), comparing between the
patients below six months and above.
Material and Methods
The presentstudy was done prospectively in the Neurosurgery
Department, Dhaka Medical College Hospital, Islami Bank
Central Hospital, and Ibn Sina Hospital, Dhaka, Bangladesh,
on infants (age 12 months) with obstructive HCP due
to CAS, admitted in the period from January 2009 to
June 2013. Failed VP shunts in CAS cases were also included.
CAS patients associated with arachnoid cyst, meningocele, or
myelomeningocele were excluded (to make the study
homogeneous) where CAS caused triventriculomegaly. The
patients whowere not available for at least 6-month follow-up
were not included in the study. (Regular follow-up in a
developing country such as Bangladesh is a challenging job.
Availability of mobile and video phone calls helped in regular
follow-ups in these cases. Sometimes we had to pay some
money to the parents for meeting up their traveling cost.)
For diagnosis of HCP, ultrasonogram (USG), computed
tomography (CT) scan, and magnetic resonance imaging
(MRI) of the brain were used. USG of the brain was done in
eight cases as a screening test by the attending physician.
CT scan of the brain was done in 15 cases and MRI was
done only in 2 cases because the parents were unwilling to
let the infants undergo general anesthesia. After making
the diagnosis, we counseled the patient’sparentsyabout
the probability of high failure rate of ETV in this age group
and probable necessity of a second operation. With the
informed consent, we performed ETV in these cases. The
study was carried out to assess the success rate of ETV as a
treatment for this type of HCP in such age group. Patients were
followed up postoperatively from days 1 through 7; then
weekly assessment for 2 months, and then monthly
assessment for 12 months followed by 3 monthly
assessment of the head circumference, anterior fontanelle,
cerebrospinal fluid (CSF) leak, wound infection, fever, or
any other complaints. ETV was considered as successful
if the patient improved clinically. Control neuroimaging
studies were done whenever needed (suspected failure
of ETV and suspected stomal block) or after 6 months to
1 year.
Operative Technical Points
The operative technique of ETV is standardized and is not
mentioned here. After making an opening in the third
ventricular floor, endoscope was advanced below through
the opening to inspect further. If an imperforate membrane of
Liliequist was identified, lying beneath the floor of the third
ventricle was opened under direct endoscopic visualization.
If any hemorrhage was encountered during the procedure,
copious warm fluid irrigation was used until all bleeding was
visibly stopped and the ventricular CSF was clear. We used
careful intermittent closure of outflow channel to create
tamponade effect. In one patient, in whom irrigation failed to
clear vision, blood-stained CSF and normal saline were
aspirated by a Fogarty catheter whose tip was cut off before
aspiration. After removal of endoscope with sheath, wound
was closed accordingly. First dural closer was done, and then
bone dust and spongostan were placed at the burr hole.
Pericranial-aponeurotic layer was closed carefully. Finally skin
was closed with interrupted stitches.
Results
Total 17 infants were studied, out of these 8 (47%) were male
and 9 (53%) female. Follow-up range was 7 to 37 months
(average: 18.7 months). Details of all patients are shown in
►Tables 1 and 2. There were seven (41%) infants aged 3
months or younger and three (17.6%) were 2 months old or
younger. Twelve (70.6%) were 6 months or younger whereas
five (29.4%) were older than 6 months to 1 year. No one was
born prematurely. There was history of febrile illness in the
mother during pregnancy among three infants. Ten (58.8%)
infants were the first issue of the parent. One patient had
history of mild birth asphyxia. Two infants had completely
healthy twin siblings. Mild to moderate underweight was
present in six (35%) cases. Gross protein energy malnutrition
(marasmus) was present in one case for which concurrent
nutritional therapy had to given during the perioperative
period of ETV. Low-birth weight (LBW) was present in three
(17.6%) cases. Three, four, five, and five infants were aged 2
months or younger, 02
þ
to 03 months, 03
þ
to 06 months,
and 06
þ
months to 1 year, respectively. There was no history
or event of pre-ETV intraventricular hemorrhage or
infection (even in failed VP shunt cases). Fourteen (82.35%)
out of 17 patients showed overall clinical improvement
(►Figs. 1–3). Clinical improvement was seen in two (66.6%)
infants aged 2 months or younger, three (75%) aged 2
þ
to 3
months, five (100%) aged 3
þ
to 6 months, and four (80%)
aged 6
þ
months to 1 year. Out of three LBW infants (all
aged <2 months), one (33.3%) patient failed ETV. Average
age of this series was 5.5 months. The mean age of the
patients with success was 5.6 months. Average ETV success
score (ETVSS) of the series was 52.35. Average ETVSS was
47.5 (range: 40–50) and 64 (60–70) in infants aged 6 months
or younger and 06
þ
to 12 months age group, respectively.
Two patients had bleeding during surgery. In one case,
continuous irrigation along with endoscopic tip pressure
and pressure by inflated Fogarty balloon were needed to
Indian Journal of Neurosurgery
ETV for Cerebral Aqueductal Stenosis in Infant Chowdhury et al.

stop bleeding. Force aspiration through sheath channel and
“cut tip Fogarty catheter”needed to make vision clear in
other case. No procedure had to be abandoned. Three
patients developed CSF leak through the burr hole. Leak
stopped spontaneously in 3 days in one patient. One patient
needed three times lumbar puncture whereas in the
remaining patients (there was perioperative hemorrhage),
repeated lumbar puncture and re-ETV failed to resolve the
problem and finally VP shunt was needed. In one patient
(age 2 months), the stoma was found blocked and HCP
returned 9 weeks after ETV. As re-ETV failed in this case, the
authors went for VP shunt that resolved the problem. In
another case in which ETV failed (ETV was done at the age of
9 months for complication of previously done VP shunt), we
had to return to VP shunt. Where VP shunt was needed,
“failed ETV”was obvious in early postoperative period cases
in two cases, and in the remaining cases, features of HCP
reappeared 9 weeks after ETV due to stomal block. The
patients’ages were was 2, 4, and 9 months at the time of ETV
when VP shunts were needed. We faced no mortality,
diabetes insipidus (DI), or endocrine abnormalities.
Transient postoperative fever was found in three cases.
ETV was done in five cases in which previously done VP
shunt was failed; four out of five responded well with ETV
and one needed repeat VP shunt.
Discussion
New interest developed in the use of ETV for the treatment
of obstructive HCP along with advanced fiberoptic and lens
technology. In recent time, the better success of third
ventriculostomy could be attributed to better patient
selection and improvements in endoscope, better imaging,
advanced surgical technique, and instruments. ETV is
considered treatment of choice in obstructive HCP. It is
also now used in some communicating HCP, such as normal
pressure HCP by some authors. Although ETV can be used in
selected patients of all types of HCP, the success of ETV in
obstructive HCP is better than that in communicating HCP.4
Obstructive HCP occurs commonly due to congenital CAS,
posterior third ventricle tumor, cerebellopontine angle tumor,
and other posterior fossa tumor of obstructive variety. HCPs
following cerebellar infarct, Dandy-Walker malformation,
syringomyelia with or without Chiari’smalformation,shunt
malfunction, encephalocele, craniosynostosis, and intraventricular
hematoma are usually of obstructive type. Myelomeningocele
withHCP,slitventriclesyndrome,andmultiloculatedHCPsare
also of obstructive type. HCP secondary to intraventricular
hemorrhage, ventriculitis, meningitis, and postoperative cases
after complete excision of mass lesions are of communicating
variety. Normal pressure HCP is of communicating type. When
Table 1 Detailsofpatients:0–6monthsofage
Age (mo),
sex and,
figure
Diag-
nosis/
ETVSS
Pre-ETV
VP shunt
H/O birth
asphyxia,
premature
delivery,
LBW, PEM
Perioperative
complication
Postoperative
complication
F/U
(mo)
ETV failed/
Stoma
block
Reoperation
4/F
(►Fig. 1)
CAS/50 –– – – 14 ––
4/F CAS/50 Bleeding CSF leak—LP
failed
32 Failed ETV Re-ETV
failed: VP
shunt done
3/F CAS/50 –– – – 27 ––
23 d/F CAS/40 –LBW ––15 ––
2/F CAS/50 –– – – 10 ––
5/M CAS/50 –– – – 7––
5/M CAS/40 Failed VP
shunt
–– – 23 ––
3/F
(►Fig. 2)
CAS/50 –– Bleeding CSF leak-
healed by LP
37 ––
3/F CAS/50 –– – Fever 09 ––
3/M
(►Fig. 3)
CAS/50 –– – – 11 ––
5/F CAS/40 Failed VP
shunt
–– – 12 ––
2/M CAS/50 –LBW ––21 Stoma
blocked-
9wkafter
ETV
Re-ETV
failed: VP
shunt done
Abbreviations: CAS, cerebral aqueductal stenosis; CSF, cerebrospinal fluid; ETV, endoscopic third ventriculostomy; ETVSS, ETV success score; F/U,
follow-up; F, female; LBW, low-birth weight; LP, lumbar puncture; M, male; PEM, protein energy malnutrition; VP, ventriculoperitoneal.
Indian Journal of Neurosurgery
ETV for Cerebral Aqueductal Stenosis in Infant Chowdhury et al.

boththeelementofobstructionandthedefectintheCSF
absorption persist, it is complex HCP.4,13
CAS is a common cause of obstructive (noncommunicating)
HCP. It could be due to congenital stenosis, acquired idiopathic,
postinfectious or posthemorrhagic, and stenosis secondary to
tumor. In congenital stenosis, aqueduct could be narrow or
completely obstructed. Complete or near-complete obstruction
usually presents in an early age, whereas if obstruction is
partial, patients may be asymptomatic or present at an later
age. ETV instead of a shunt placement is considered a better
option for noncommunicating HCP secondary to congenital
aqueductal stenosis. Results of ETV are better in congenital HCP
Table 2 Detailsofpatients:6
þ
–12 months of age
Age (mo)
and sex
Diag-
nosis/
ETVSS
Pre-ETV
VP shunt
H/O birth
asphyxia,
premature
delivery,
LBW, PEM
Perioperative
complication
Postoperative
complication
F/U
(mo)
Stoma block Reoperation
9/M CAS/60 VP shunt
block with
downward
migration
PEM
(marasmus)
–– 35 ––
12/M CAS/70 –– – CSF leak:
stopped
spontaneously
21 ––
9/M CAS/60 CSF leak at
abdominal
end of VP
shunt (at
the age of
3mo)
Mild birth
asphyxia
None None 15 ETV failed
(failed to
improve
symptoms)
Re-VP shunt
on the
opposite
side
12/F CAS/70 –– – – 36 ––
9/M CAS/60 VP shunt:
at the age
of 2 mo
–– Fever 13 ––
Abbreviations: CAS, cerebral aqueductal stenosis; CSF, cerebrospinal fluid; ETV, endoscopic third ventriculostomy; ETVSS, ETV success score; F,
female; F/U, follow-up; M, male; mo, month; PEM, protein energy malnutrition; VP, ventriculoperitoneal.
Fig. 1 Upper row—preoperative serial axial CT scan of brain showing triventriculomegaly at the age of 4 months. Lower row—postoperative
serial axial CT scan of brain at the age of 2 years. CT, computed tomography.
Indian Journal of Neurosurgery
ETV for Cerebral Aqueductal Stenosis in Infant Chowdhury et al.

due to aqueductal stenosis as compared with posthemorrhagic
or postinfective HCP.4,5 Perioperative neural injury, such as
thalamic, forniceal, hypothalamic, and midbrain, are not
uncommon. Intraoperative bradycardia and hemorrhages
including fatal hemorrhage due to basilar artery rupture are
also reported. Attempts to perforate the ventricular floor can
lead to bleeding, especially in HCP following an infection
and hemorrhage. From our experience, all can be easily avoided
by appropriate placing of burr hole and careful surgical
manipulation of endoinstruments and neurostructures.
Significant side movement should be avoided to prevent
bleeding due to an injury to structures, such as the fornix and
veins at foramen of Monro. We did not face any neural damage
except controllable bleeding per operatively. Rarely, blood
might trickle from burr-hole site into the ventricle; proper
hemostasis must be achieved before entering the ventricle.4
Perioperative bleeding is seen in about 3 to 8%3,14 of cases.
Aspiration of clots and thorough irrigation of ventricular cavity
should be done after bleeding stops; these measures can reduce
chances of stoma closure.3Bradycardia may occur from raised
ICP due to inappropriate irrigation and brainstem stretching.4
Central nervous system infections, fever, stoma block, CSF
leak, and postoperative intracranial hematomas were also seen.
Postoperative mortality is also reported.15,16 DI, hemiparesis,
gaze palsy, memory disorders, altered consciousness, weight
Fig. 2 (A) Preoperative picture of patient with hydrocephalus. (B)
Preoperative MRI sagittal section in T1W image showing
triventriculomegaly with CAS. (C) Early postoperative picture of
patient after ETV. (D) Late postoperative picture of patient with
successful ETV. CAS, cerebral aqueductal stenosis; ETV, endoscopic
third ventriculostomy.
Fig. 3 (A) Preoperative picture of patient with hydrocephalus. (B) Pre-E TVC Tscan axial sections show ing triventriculomegaly due to CAS. (C, D)
Early postoperative pictures of patient with successful ETV. CAS, cerebral aqueductal stenosis; CT, computed tomography; ETV, endoscopic
third ventriculostomy.
Indian Journal of Neurosurgery
ETV for Cerebral Aqueductal Stenosis in Infant Chowdhury et al.

gain, precocious puberty, and abnormal prolactin levels can
occur after ETV. However, abnormal prolactin levels are not
clinical significant.17 DI was reported by Choi et al18 in 3%
cases. Chronic subdural hematoma or subdural hygroma can
occur after ETV. Rare complications such as postoperative
hyperkalemia, severe parkinsonism, acute respiratory alkalosis,
and tachypnea can occur after ETV. Overall complication rate
after ETV is about 2 to 15%, but the permanent complications are
few.4,19–21
Postoperative fever could occur due to use of electrocautery,
which should be avoided. We faced postoperative fever in three
cases that subsided spontaneously. Postoperative CSF leak could
be avoided by plugging cortical and dural opening by Gelfoam,
direct dural closure, especially in large ventriculomegaly in
infants, or by using artificial dural substitute and tissue sealant
in at-risk patients. Postoperative CSF leak can also be reduced
by galeal-pericranial flap.4,22 Incidence of CSF leak after ETV
have varied between 2 and 7%. In the series of Yadav et al, CSF
leak occurred in 16% patients in whom half of the cases of CSF
leak stopped spontaneously. The causes of persistent leak
includeclosureofstoma,failureofclosureofthedura,thinned-
out scalp, and thin cortical mantle in patients with gross HCP.
Dura closer should be done properly, especially in patients with
gross HCP with thin cortical mantle.3Postoperative
complications in the ETV patients usually occur within
1 month after operation. However, delayed complications
including stoma block can occur. Delayed stoma block, though
very rare, can be fatal.23 Intraoperative observation of thickened
arachnoid membranes at the level of the interpeduncular
cisterns at the time of ETV should be considered a significant
risk of stoma block.24 Postoperative failures usually occur early;
regular clinical and radiologic follow-up must be performed,
especially in the first years after the ETV.25 According to
Mohanty et al,26 reclosure of the stoma because of gliosis and
scarring has been observed in 6 to 15% of ETV failures. The high
rateofreclosureininfantscanbeexplainedasfollows:asCSF
absorption is impeded, there is a greater tendency for the
development of new arachnoid membranes in infants, and
there is also growth of gliotic, ependymal, and scar tissue.12 ICP
monitoring with or without external ventricular drainage
during the immediate postoperative period after ETV could be
required in patients who continue to have clinical features of
raised ICP or failed to show an improvement after ETV. Few
patients fail to show an improvement despite patent stoma
after ETV. CSF drainage by lumbar puncture helps by increasing
thecomplianceandthebufferingcapacitiesofthespinal
subarachnoid spaces. It probably decreases the CSF outflow
resistance from the ventricular system, facilitates the decrease
in the ventricular volume, and allows faster permeation of CSF
in the intracranial subarachnoid spaces. A cycle of one to three
lumbar punctures should always be performed in patients who
remain symptomatic after ETV, before ETV is assumed to have
failed.4,27–29
A reduction in the ventricular size detected soon after
ETV is associated with a good clinical outcome. This decrease
in ventricular size continues during the first few months
after surgery. Reduction in the size of third ventricle width is
more than that in lateral ventricle size width after successful
ETV. Magnetic resonance ventriculography was effective in
assessing subarachnoid space and stoma patency after ETV.
T2-weighted turbo inversion-recovery magnetic resonance
images can detect flow-void sign better. Cine phase-contrast
(PC) MRI is useful even if no flow void is seen. Cine PC MRI
may be used to determine the patency of the stoma and may
be used in follow-up.4,24,30,31
Determining the best candidates for ETV has been difficult,
with conflicting reports on who are the best candidates,
particularly regarding the effect of age and etiology. Reports
have indicated that outcome is a function of age23,32,33
independent of age,1,34 a function of etiology,1,35–37 or a
function of both age and etiology.38 More recent evidence
from larger, and in one case, multicenter series has supported
the finding that age is the main determinant of outcome with
younger children, particularly neonates, faring worse.39,40 The
other standard technique of CSF diversion, a CSF shunt, has
rarely been compared with ETV, with results suggesting no
difference41 or a slight advantage in terms of cost-
effectiveness for ETV.42 CSF shunt outcomes are also known
to be influenced by age, with younger children also faring
more poorly.43–45
There are controversies regarding the success of ETV in
infants. Some authors reported poor results, especially in
neonates and in infants younger than 2 months.4Shim et
al46 suggested that simultaneous ETV and VP shunt should
be performed in infantile HCP due to poor results of ETV
alone. The higher clinical success rate of ETV in the series by
Yadav et al was 83.7%.3Success rates of 71%,47 64%,48 and
85%49 were observed in other studies done in infants
whereas the success rates varied from 7614 to 91.5% in
other age group patients.18 They found that failure rate of
ETV in LBW premature infants was higher (60%) as
compared to full-term normal-birth-weight infants
(12.3%).3In the case of children under 1 year, long-term
shunt independence was 75% in the series by Stan et al.50
The success of these patients was influenced much by the
technique used. In the absence of plexus coagulation, the
success rate of the operation is significantly reduced. The
study by Warf et al proved the difference in the success rate
with 48.6% in patients in whom they practiced only ETV
compared to 81.9% in those in whom they practiced ETV and
plexus coagulation both.51 Kulkarni et al52 reported the
relative higher risk of initial failure in ETV than shunt in
children. The relative risk becomes progressively lower for
ETV after about 3 months. Patients could experience a long-
term treatment survival advantage after an early high-risk
period of ETV failure as compared to shunt. They observed
that it might take several years, however, to realize this
benefit. There have been several studies of the effectiveness
of ETV in children under two years of age. Kadrian et al
reported a strong effect of the patient’s age on outcome.40
The authors reported the percentages of patients “presumed
to have a functioning ETV after 5 years”as follows: 41% in
patients 1- to 6-month old at the time of surgery, 58% in
patients 6- to 24-month old, and more than 70% in patients
older than 24 months. These results correspond to the data
reported by other authors.32 However, Javadpour et al47
Indian Journal of Neurosurgery
ETV for Cerebral Aqueductal Stenosis in Infant Chowdhury et al.

reported ETV success rate of 33% (continued patency during
follow-up in 7 of 21 patients) and found that success
depended on etiology rather than on patient age. Baldauf
et al38 reported 50% success rate in idiopathic aqueductal
stenosis. Analysis of the success and failure of ETV in infants
in the Netherlands confirmed that ETV should be considered
as an initial treatment that carries a low risk of morbidity in
these infants. As the immune system rapidly matures,
postponing shunt implantation for several months or even
weeks would make ETV worthwhile. Moreover, the authors
noted that a second ETV should always be considered before
shunt placement in young patients with a failed ETV, as the
probability of ETV success rapidly increases 4 months after
birth.53 The largest study of ETV success in very young
children was conducted in Uganda and it involved 153
children younger than 1 year.54 The ETV success rate among
these patients was 53%. The surgery success rates for
patients with aqueductal obstruction were 70%. Fritsch et
al,1reporting a 39% ETV success rate, presented ETV as an
effective alternative for the treatment of obstructive HCP in
infants younger than 1 year. Korean authors have reported
simultaneous implantatio n of a VP shunt and ETV as the first
choice of treatment for hydrocephalic patients younger than
1 year (83.9% success rate). Perhaps placement of the
ventricular catheter in the prepontine cistern under
endoscopic guidance reduces the risk of stoma closure and
development of new arachnoid membranes.55 On the other
hand, these combined procedures do not provide patients
with shunt independence and or freedom from shunt
complications.12 In the small series of ETV under the age
of 6 months in obstructive HCP due to CAS, Zodi et al found
very low success rate (only 12.5% cases were successful).12
Success rates of ETV in different series are shown in
(►Table 3).1,11,12,25,39,41,48,51,56–60 ETVSS is used to predict
the outcome of ETV before operation.52 In this series,
average ETVSS was 52.35 (range: 40–70) and overall
success rate was 82.35%. This indicates that ETVSS does not
correlate with the outcome of ETV in infants with CAS. In our
series, we did not find any impact of age on the success of
ETV in CAS. In this small series, success rate of ETV in CAS
under the age of 1 year was not low (82.35%) without
choroid plexus coagulation. It is not well understood; result
of success in ETV in obstructive HCP in infant was so variable
in different series. During operation the authors frequently
noticed extra-arachnoidal membrane after fenestration of
third ventricular floor; the authors went for fenestration of
that membrane(s) almost routinely to the anterior surface of
the basilar artery. In future, larger series with more number
of cases will probably answer the question preciously.
Conclusion
Outcome of ETV for HCP from CAS in infant is quite good
with low risk of complication even in very young infant, and
ETVSS does not correlate with the outcome.
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Table 3 Comparative success rate of ETV in aqueductal obstruction by some published series
Series No. of patients Age group Result of success
rate (%)
Fritsch et al (2005)13 Pediatric (<1 y) 100
Cinalli et al (1999)11 119 Pediatric 72
Zohdi et al (2013)12 08 Pediatric 12.5
Gangemi et al (2007)25 88 Pediatric plus adult 87
Drake (2007)39 107 Pediatric 65 and 52 success rates at 1 and
5 y, respectively
Tuli et al (1999)41 32 Pediatric 56
Gorayeb et al (2004)48 11 Pediatric (<1y) 55
Warf et al (2005)51 153 Pediatric 53 in all patients and 70 in
aqueductal obstruction
Fukuhara et al (2000)57 37 Pediatric plus adult 68
Bognar et al (2005)58 76 Pediatric plus adult 71
Koch-Wiewrodt and Wagner (2006)59 13 Pediatric (<1y) 54
Sacko et al (2010)60 350 Pediatric plus adult 61
Abbreviation: ETV, endoscopic third ventriculostomy; y, year.
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