Cooperative study by the Italian neuroendoscopy group on the treatment of 61 colloid cysts.

Abstract

Microsurgical resection, stereotactic aspiration and VP shunt have for years been the choice options for the treatment of colloid cysts of the third ventricle. Recently, endoscopic approaches have aroused increasing interest and gained acceptance. Although safer, this minimally invasive approach is considered less efficacious than microsurgery. Relatively long-term results are now available and some conclusions might be inferred on the usefulness of this procedure.
Between 1994 and 2005, 61 patients harbouring a colloid cyst of the third ventricle were treated with neuroendoscopic technique in 11 Italian neurosurgical centres. Cyst diameters ranged from 6 to 32 mm. A flexible endoscope was used in 34 cases, a rigid one in 21, both instruments in six. The technique consisted in cyst fenestrations, colloid aspiration, coagulation of the internal cyst wall and, occasionally, capsule excision. Mean postoperative hospital stay was 6.7 days. Early postoperative neuroimaging revealed a cyst residue in 36 cases (mean diameter 4.3 mm). There were two complications (3.2%). Follow-up varied between 1 and 132 months (mean 32 months, more than 5 years in 17 patients). There were seven asymptomatic recurrences, three of them evolving from a previous residue.
The endoscopic approach to the treatment of colloid cysts is safe, effective and well accepted by patients. Although asymptomatic, recurrences (11.4%) cast a persisting shadow on the long-term results, and, therefore, the controversy with the traditional microsurgical treatment remains open.

Full text

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Childs Nerv Syst (2006) 22: 1263–1267
DOI 10.1007/s00381-006-0105-8
ORIGINAL PAPER
P. Longatti
U. Godano
M. Gangemi
A. Delitala
E. Morace
L. Genitori
C. Alafaci
L. Benvenuti
A. Brunori
C. Cereda
S. Cipri
A. Fiorindi
F. Giordano
C. Mascari
P. A. Oppido
A. Perin
M. Tripodi
Received: 30 September 2005
Revised: 13 November 2005
Published online: 29 April 2006
# Springer-Verlag 2006
Cooperative study by the Italian
neuroendoscopy group on the treatment
of 61 colloid cysts
Abstract Objects: Microsurgical
resection, stereotactic aspiration and VP
shunt have for years been the choice
optionsforthetreatmentofcolloidcysts
of the third ventricle. Recently, endo-
scopic approaches have aroused in-
creasing interest and gained acceptance.
Although safer, this minimally invasive
approach is considered less efficacious
than microsurgery. Relatively long-term
results are now available and some
conclusions might be inferred on the
usefulness of this procedure. Materials
andmethods: Between1994and2005,
61 patients harbouring a colloid cyst of
the third ventricle were treated with
neuroendoscopic technique in 11 Italian
neurosurgical centres. Cyst diameters
ranged from 6 to 32 mm. A flexible
endoscope was used in 34 cases, a rigid
one in 21, both instruments in six. The
techniqueconsistedincystfenestrations,
colloid aspiration, coagulation of the
internal cyst wall and, occasionally,
capsule excision. Mean postoperative
hospital stay was 6.7 days. Early post-
operative neuroimaging revealed a cyst
residue in 36 cases (mean diameter
4.3 mm). There were two complications
(3.2%).Follow-upvariedbetween1and
132 months (mean 32 months, more
than 5 years in 17 patients). There were
seven asymptomatic recurrences, three
of them evolving from a previous resi-
due. Conclusion: The endoscopic ap-
proachtothetreatmentofcolloidcystsis
safe, effective and well accepted by
patients. Although asymptomatic,
recurrences (11.4%) cast a persisting
shadow on the long-term results, and,
therefore, the controversy with the
traditional microsurgical treatment
remains open.
Keywords Colloid cyst.
Neuroendoscopy.Third ventricle
tumor.Microsurgery.Stereotactic
aspiration.Recurrence.
Cooperative study
Introduction
Colloid cysts of the third ventricle are rare intracranial
lesions,usuallylocatedattheleveloftheforamenofMonro.
Microsurgery or bilateral CSF shunting have long been the
preferred treatment options. Stereotactic puncture was also
advocated in the past [1–4], but soon abandoned on account
of the high relapse rate of both cysts and symptoms [5].
With the renaissance of neuroendoscopy, many authors
have proposed this minimally invasive technique for the
P. Longatti.A. Fiorindi (*).A. Perin
Ospedale di Reggio Calabria,
Reggio Calabria, Italy
e-mail: afiorindi@ulss.tv.it
Tel.: +39-422322576
Fax: +39-422322523
U. Godano.C. Mascari
Ospedale Bellaria, Bologna, Italy
A. Delitala.A. Brunori
Ospedale S. Camillo, Rome, Italy
L. Genitori.F. Giordano
Ospedale Pediatrico Meyer,
Firenze, Italy
M. Gangemi
II Università di Napoli, Naples, Italy
E. Morace.P. A. Oppido
Istituto Regina Elena, Rome, Italy
L. Benvenuti
Ospedale di Livorno, Livorno, Italy
M. Tripodi
Ospedale di Brindisi, Brindisi, Italy
C. Cereda
Spedali Civili di Brescia, Brescia, Italy
C. Alafaci
Università di Messina, Messina, Italy
S. Cipri
Ospedale di Reggio Calabria,
Reggio Calabria, Italy

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treatment of colloid cysts [6–12]. Although continually
reported to be an excellent alternative to microsurgery, the
results have been criticised because of the excessively short
follow-up. This paper retrospectively reviews 61 cases of
colloid cysts treated endoscopically during the last decade in
11 Italian neurosurgical centres, with the aim of presenting
resultsandcomplicationsinthelargestseriespublishedtodate.
Materials and methods
Sixty-one patients (34 males and 27 females, mean age
41 years, range 9–78 years) harbouring a colloid cyst of the
third ventricle, were treated by the neuroendoscopic
technique in 11 Italian neurosurgical centres between
March 1994 and January 2005. Of the 61 patients, 72%
presented symptoms of intracranial hypertension, 20% had
cognitive disturbances, 15% had gait imbalance; only two
patients were asymptomatic. In 7% of the cases, clinical
onset was acute with neurological deterioration evolving to
coma. Four patients had undergone previous treatment of
the cyst (stereotactic aspiration in three cases, craniotomy
in one case). Preoperative MRI scans were reviewed in 53
out of 61 cases (87%): cyst diameter ranged from 6 to
32 mm (mean 14.6 mm); cysts were hyperintense in 70% of
the cases, isointense in 17% and hypointense in 13%
(Figs. 1a and 2a). Biventricular hydrocephalus was present
in 87% of the patients. Eight patients (13%) did not present
hydrocephalus: endoscopic treatment in these cases was
supported by stereotaxis in two and by neuronavigation in
the other two. Altogether, the procedures were supported
by neuronavigation in six cases and by stereotaxis in two
cases. A flexible endoscope was used in 34 cases, a rigid
one in 21, both instruments in the same procedure in six.
The entry point was variable, ranging from 2 to 5 cm from
midline and 1 to 4 cm ahead of the coronary suture.
Results
A total of 66 procedures were performed in 61 patients: 58
patients underwent one procedure; removal was largely
incomplete in four patients, three of whom underwent early
reoperation; there was a misdiagnosis in two cases (one
low-grade glioma and one cavernoma of the Monro
foramen). The mean operating time was 87 min (range
20–300 min). The technique consisted in cyst fenestrations
and colloid aspiration (100% of cases), capsule and internal
wall coagulation (80.3%), partial capsule excision (52.4%)
and total cyst removal (9.8%). In 20 cases (32.8%), a
ventricular catheter was left in place for a few days after
endoscopy to manage a possible acute obstruction of CSF
circulation. Cyst residue (defined as the remainder of the
colloid cyst shown on an early postoperative MRI scan)
was observed in 62.3% of cases, with a mean diameter of
5 mm (range 1–19 mm).
There was no mortality related to the operation. Mean
hospital stay was 6.7 days. Surgical morbidity was 3.2%:
a temporary hemiparesis was observed in one patient,
while a case of septic ventriculitis (Staph. Epid) was
managed by antibiotic therapy. However, the persistence
of triventricular hydrocephalus prompted a second
endoscopic procedure, which did not reveal any altera-
tion in CSF circulation. A third ventriculostomy was,
nevertheless, performed, but 20 days later a myelocis-
ternography showed a communicating hydrocephalus
that required a VP shunt. The final clinical status of this
patient was substantially unchanged, compared to the
preoperative evaluation. There where four minor asymptom-
atic complications: three patients showed early intraventric-
ular haemorrhages, while one patient developed a trajectory
haematoma; none, however, required any treatment.
Follow-up ranged from 1 to 132 months (mean
32 months, more than 5 years in 17 patients). There were
seven recurrences (11.4%), all asymptomatic, three of them
evolving from a previous residue; in two cases, the
recurrence did not determine ventricular enlargement.
Features of the recurrences are summarized in Table 1.
Fig. 1 Preoperative MRI of
patient 5, showing an hyperin-
tense T1-weighted cyst (a); MRI
image showing, 40 months later,
a large hypointese recurrence
(b) causing only moderate hy-
drocephalus, compared to the
preoperative condition
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Discussion
Treatment of colloid cysts is still a matter of debate, and a
definitive conclusion has not yet been reached. In the past,
stereotacticaspirationwith1.8–2.1mmneedlesseemedtobe
theleastinvasiveprocedure[13],butahigherriskoftransient
cognitive impairment than with the more invasive micro-
surgical approach was reported [14]. Besides the effective-
nessofaspirationbeingheavilydependentuponcystsizeand
colloid density [13], the frequency of relapses also proved to
be exceedingly high and often precocious [5, 15], and,
therefore, this technique has now been almost abandoned.
Microsurgical removal has for years been considered the
“gold standard” of radical treatment for colloid cysts.
Nevertheless, even in very experienced hands, microsurgery
implies up to 27% postoperative morbidity [14, 16–20] with
substantial mortalityrates, reported by some authors tobe up
to 5.3% [14, 19, 20]. Transcallosal microsurgery has also
been associated with vascular complications due to venous
infarction, injury to pericallosal arteries, and fornix damage
with cognitive sequelae [14, 21–23].
Fig. 2 A case of stable residue:
preoperative MRI (a) showing a
an isointense cyst; at the post-
operative MRI scan, a hyperin-
tense residue is visible (b); a
little increase in residue diame-
ter is detectable 32 months later
(c), while 76 months after en-
doscopy (d), there is no further
evolution; note that hydroceph-
alus progressively decreased
Table 1 Features of the recurrences
Patient # and age MRI cyst intensity Cyst size (mm) Postoperative residue Surgical actionsRecurrence time
(months)
Recurrence size
(mm)
1
2
3
65 years
54 years
60 years
Hypo
Hypo
Hyper
25
18
8
None
None
2 mm
Aspir + caps coag
Aspir + caps coag
Aspir + coag +
partial caps exc
Aspir + coag +
partial caps exc
Aspir + caps coag
Aspir + coag +
partial caps exc
Aspir + partial
caps exc
79
72
48
10
9
8
431 years Iso122 mm 42 8.6
5
6
63 years
51 years
Hyper
Hyper
12
22
None
7 mm
819
725
739 years Hyper8None 1510
Hypo Hypointense, Hyper hyperintense, Iso isointense, Aspir aspiration, Caps capsule, Coag coagulation, Exc excision
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Neuroendoscopic management of colloid cysts of the
third ventricle is emerging as a safe, effective alternative to
the well-established approaches of microsurgical removal
[6–12], and our work further corroborates this point.
The fact that the study involved the experience of several
centres further strengthens the results by indicating the
impact of the neuroendoscopic technique on a vast
population, without bias related to personal surgical skill
or institutes of excellence.
The various authors in literature reported the most
relevant advantages of the endoscopic approach over
microsurgery to be shorter operation time [18], decreased
hospital stay, more rapid return to active life [4] and low
direct surgical morbidity. In the larger series, Decq [9]
reported a 6.6%, Abdou [8] a 7.7%, Schroeder [11] an
8.3% and Hellwig [12] a 10% complication rate.
No fatal complications have been reported for endo-
scopic treatment of colloid cysts, and the substantial
reduction in both morbidity and mortality is related to the
minimal invasiveness of neuroendoscopy. This was con-
firmed by Kelher [24], who compared two series of colloid
cysts, one treated with microsurgery and the other with
neuroendoscopy: complete resection was achieved in eight
outoftencasesofmicrosurgeryandinthreeoutoftencases
of endoscopy. Better excisions were counterbalanced by
three major postoperative complications in the microsurgi-
cal group, longer operation time and longer hospital stay
(91 vs 267 min and 5.1 vs 18.9 hospital days, respectively).
Despite these obvious advantages, early postoperative
residues and recurrences are the main cause for concern
and debate on the long-term effectiveness of neuroendo-
scopy. Our cooperative study represents the largest series to
date of colloid cyst patients treated with the endoscopic
technique. Approach was obviously variable, depending
especially on the surgeons’ personal habits and instrumen-
tation, on the position of the cyst, particularly in respect to
Monro foramen (Figs. 3 and 4) and on the typology of
ventricular enlargement (that is, usually asymmetric and in
these cases the most dilated ventricle is usually preferred);
in any case, the entry point is more anterior and more
lateral (about 3 cm ahead of the coronary suture and 3.5 cm
lateral to the midline on average) in respect to a ventric-
ulostomy for positioning of a ventricular catheter.
The technique consisted in cyst fenestrations and colloid
aspiration in all cases, capsule and internal wall coagula-
tion in 80.3%, partial capsule excision in 52.4%, while total
cyst removal was possible only in 9.8% of cases. Both the
problems of the approach and of the surgical actions are
more relevant when ventricles are not significantly
enlarged. In these cases, a support (stereotaxis or
neuronavigation) is, in our opinion, mandatory; surgical
actions must be reduced to minimum and tractions or
excessive manipulation must be avoided: in five of our
eight cases without hydrocephalus, only colloid aspiration
and capsule coagulation were performed, while in only
three cases also a partial capsule excision was attempted.
The fact that the unique neurological deficit we observed
postoperatively, a transitory hemiparesis, occurred in a case
of colloid cyst without hydrocephalus treated with no
guidance support is somehow relevant.
Cyst residues, detected in early postoperative neuroima-
ging, were present in our series in 62.3% of the cases.
Thirty-four of these cyst residues did not increase at
follow-up, one of them even shrank and only three out of
our seven recurrences evolved from an increase in a
previous residue. Hence, the correlation between the
presence of residue and the incidence of recurrence does
not seem so robust.
Hellwig described only one recurrence in 20 cases (the
patient underwent repeat endoscopy) [12], Schroeder
reported three stable residues and one increased residue
in 12 cases, without clear recurrences [11], while Decq
experienced three residues and one recurrence in 15 cases
[9] and Kelher one recurrence in ten patients [24].
All our recurrences (Table 1) were asymptomatic and
their signal on MRI did not always reflect the aspect of the
original cyst (Figs. 1 and 2): T1-weighted hyperintense
lesions resulted in a hypo- or isointense recurrence in two
cases, while two cases of iso-hypointense cyst gave rise to
Fig. 4 Intraoperative picture of a colloid cyst entirely occupying
Monro foramen; note how the choroid plexus is completely
displaced to the anterior part of the foramen in respect to its normal
position (Fig. 3)
Fig. 3 Intraoperative picture showing endoscopic Monro foramen’s
anatomy from the lateral ventricle
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an iso- or hyperintense relapse. As five out of seven
recurrences occurred within 4 years of endoscopy, a strict
follow-up with MRI at least once a year is recommended
especially in the early years, although our two late
recurrences show that the risk is likely to be lifelong.
Another critical point could be the management of
recurrences and residues (Fig. 2): when and if to re-treat
them and with which technique. Two of our patients with
recurrences were young and at potentially higher clinical
risk: they should, therefore, be convinced to undergo
reoperation (endoscopy or, especially when ventricles are
not enlarged, microsurgery) or, if reluctant to do so, should
be followed up more closely.
Although this report presents the limitations of a
retrospective study, it confirms that neuroendoscopic
management of colloid cysts of the third ventricle is a
safe, effective alternative to well-established microsurgical
removal approaches. Postoperative residues (expression of
partial excision) and recurrences are still a matter of
concern but are counterbalanced by the obvious advantages
of a minimally invasive technique.
Recurrences mostly occur within 4 years and, therefore,
patients should be carefully monitored during this period.
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