JOURNAL OF NEUROTRAUMA
Volume 19, Number 9, 2002
© Mary Ann Liebert, Inc.

Arachnoid Cyst Is a Risk Factor for Chronic Subdural
Hematoma in Juveniles: Twelve Cases of Chronic Subdural
Hematoma Associated with Arachnoid Cyst
KENTARO MORI, TAKUJI YAMAMOTO, NAOAKI HORINAKA, and MINORU MAEDA

ABSTRACT
Chronic subdural hematoma (CSDH) tends to occur in elderly patients with a history of mild head
injury at a few months prior to the onset of symptoms. Intracranial arachnoid cyst is believed to be
congenital and sometimes becomes symptomatic in pediatric patients. These two distinct clinical entities sporadically occur in the same young patient. Twelve of 541 cases of CSDH surgically treated
in our institution had associated arachnoid cyst. The clinical and radiological characteristics of the
cases of CSDH associated with arachnoid cyst were retrospectively analyzed and compared with
those of CSDH without arachnoid cyst. Arachnoid cysts were located in the middle fossa (eight
cases), convexity (two cases), and posterior fossa (two cases). Three cysts were less than 20 mm in
diameter. The 12 patients with CSDH and arachnoid cyst (mean age 27.8 6 19.7 years) were significantly younger (p , 0.001) than the patients with CSDH without arachnoid cyst (69.5 6 13.7
years). Five of the 12 patients were pediatric cases (,15 years old). The clinical symptoms were also
significantly different. The most frequent symptom was headache followed by vomiting in the patients with arachnoid cyst, while gait disturbance and hemiparesis predominated in patients without arachnoid cyst. Hematoma evacuation through burr holes improved the symptoms in all patients
with arachnoid cyst. We conclude that even a small arachnoid cyst can be a risk factor for CSDH
after mild head injury in young patients and symptoms of increased intracranial pressure are common. Hematoma evacuation is adequate at first operation. If the preoperative symptoms persist, additional arachnoid cyst surgery should be considered. The present results also suggest that CSDH
formation may be preceded by subdural hygroma caused by the rupture of arachnoid cyst.
Key words: arachnoid cyst; chronic subdural hematoma; head injury

INTRODUCTION

I

NTRACRANIAL ARACHNOID CYST is one of the most com-

mon clinical entities in daily neurosurgical practice.
Arachnoid cysts are generally considered to be congenital and tend to occur in children (Shaw and Alford, 1977;
Rengachary et al., 1978; Wester, 1992). Arachnoid cyst

most frequently occurs in the middle fossa, followed by
the posterior fossa, convexity, and suprasellar regions
(Shaw and Alford, 1977; Sato et al., 1983). Headache,
convulsion, deformity of the cranium with bulging and
thinning of the adjacent bone, focal neurological deficit,
and mental retardation are known symptoms of intracranial arachnoid cyst (Rengachary et al., 1978; Sato et al.,

Department of Neurosurgery, Juntendo University Izunagaoka Hospital, Shizuoka, Japan.

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MORI ET AL.
1983). Computed tomography (CT) and magnetic resonance (MR) imaging have increased the detection of incidental asymptomatic arachnoid cyst. Most symptomatic
arachnoid cysts indicated for surgical intervention occur
in pediatric patients because the cyst manifests as a space
occupying lesion in the developing brain (Galassi et al.,
1980; Sato et al., 1983; Arai et al., 1996). In addition to
cysts manifesting as chronically developing symptoms,
subdural or intracystic bleeding from bridging vein or
blood vessels sporadically occur around arachnoid cyst
after head injury (Galassi et al., 1980; Hara et al., 1984;
Page et al., 1987, 1988; Yokoyama et al., 1989; Servadei
et al., 1993; Oka et al., 1994; Albuquerque and Giannotta, 1997; Parsch et al., 1997). Middle cranial fossa
arachnoid cyst is now recognized as one of the causes of
chronic subdural hematoma (CSDH) after head injury,
especially in young people. CSDH was generally believed to occur in elderly people at several weeks after
head injury (Markwalder, 1981). The association of these
two distinct clinical entities in young patients may suggest a possible etiology of CSDH.
This study analyzed the clinical features of 12 cases
of CSDH associated with arachnoid cyst among 541 consecutive cases treated surgically from 1987 to 2000, to
investigate arachnoid cyst as a risk factor for CSDH in
young patients, the etiology of CSDH, and the treatment
of such cases.

MATERIALS AND METHODS
Five hundred and forty-one consecutive patients with
CSDH were treated by hematoma evacuation and
drainage through cranial burr holes in the Department of
Neurosurgery, Juntendo University Izunagaoka Hospital
from January 1987 to June 2000. Twelve of these 541
patients, six males and six females aged from 5 to 71
years old, had CSDH associated with arachnoid cyst
(Table 1). CT and/or MR imaging were performed in all
patients to confirm the diagnosis. The arachnoid cysts
were located in the middle fossa in eight cases, in the
convexity in two cases, and in the posterior fossa in two
cases. Eight patients had a definite history of mild head
injury and two patients had a history of operation for
arachnoid cyst, cystoperitoneal shunting in one case and
cyst opening in the other.
All hematomas were evacuated and irrigated with normal saline through two burr holes and closed system subdural drainage was continued for one or two days after
the operation. Patient 4 underwent cystoperitoneal shunting surgery after the drainage surgery because the arachnoid cyst caused mass effect to the surrounding brain. The
preoperative hematoma thickness and the postoperative

hematoma thickness (1 week after operation) were measured by CT to calculate the re-expansion rate as (preoperative hematoma thickness 2 postoperative hema-toma
thickness)/preoperative hematoma thickness 3 100 (%).
The clinical and radiological data of the patients of CSDH
with arachnoid cyst were compared with the data of the patients of CSDH without arachnoid cyst. Data are given as
the mean 6 standard deviation. Results were analyzed for
statistical significance using the unpaired Student’s t test
and Pearson’s x2-test with p , 0.05 considered significant.

RESULTS
Table 2 compares the patients with CSDH with and
without arachnoid cyst. The patients with CSDH and
arachnoid cyst (mean age 27.8 6 19.7 years) were significantly younger (p , 0.001) than the patients with
CSDH without arachnoid cyst (mean age 69.5 6 13.7
years). Five of the eight pediatric patients (,15 years
old) with CSDH had arachnoid cysts. The incidence of
association with arachnoid cysts in pediatric patients
(62.5%) was significantly higher (p , 0.001) than in
adult patients (1.3%). Sex, mean interval from trauma to
hematoma evacuation, preoperative hematoma thickness,
and the locations of CSDH were not statistically different between the patients with and without arachnoid cyst.
The incidence of high CT density hematoma in the patients with arachnoid cyst was significantly higher (p ,
0.01) than that of the patients without arachnoid cyst. The
clinical presentations were quite different between the two
groups. The most frequent symptom was headache
(83.3%) followed by vomiting (33.3%) and hemiparesis
(33.3%) in the patients with arachnoid cyst. The most frequent symptom was gait disturbance (63.5%) followed by
hemiparesis (58.0%) in the patients without arachnoid cyst.
These symptomatic differences were statistically significant (p , 0.05). The reexpansion rate of the brain at one
week after burr hole irrigation was 75.3 6 13.1% in the
patients with arachnoid cyst and was significantly higher
(p , 0.01) than that in the patients without arachnoid cyst.
All patients with CSDH and arachnoid cyst became
symptom-free after the burr hole irrigation. Follow-up CT
or MR imaging showed spontaneous disappearance of
arachnoid cyst in one patient (patient 11) and decreased size
of the arachnoid cyst in two patients (patients 8 and 9).

ILLUSTRATIVE CASES
Patient 3
A 17-year-old man complained of headache and vomiting following mild head injury due to a traffic accident

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1019

33/F

17/M

9/F

39/F
12/M

41/M

5/M

71/F

43/F
14/M

39/M

2

3

4

5
6

7

8

9

10
11

12

Traffic accident

Falling
Falling

—

Falling

Struck by person
AC operation
(cyst
opening)
Falling

Falling

AC operation
(CP shunt)
Traffic accident

—

Trauma

12w

8W
4w

—

16w

4w

9w
11w

5w

18w

4w

—

R

R
L

L

L

Bilateral

L
R

Bilateral

R

L

R

Location
of
CSDH

Headache

Headache, gait
disturbance dementia
Headache, hemiparesis
Headache, hemiparesis

Headache

Headache, vomiting

Hemiparesis
None

Headache, vomiting

Headache, vomiting

Headache, hemiparesis

Headache, vomiting

Symptoms

L–middle fossa
(type I)
L–middle fossa
(type I)
L–middle fossa
(type I)
L–convexity
L–middle fossa
(type I)
Posterior fossa

R–middle fossa
(type I)
R–middle fossa
(type II)
L–convexity
R–middle fossa
(type II)

R–middle fossa
(type I)
posterior fossa

Location of AC
(Galassi
classification)

27 3 21mm

16 3 10mm
15 3 7mm

24 3 20mm

42 3 17mm

33 3 17mm

16 3 10mm
29 3 26mm

43 3 28mm

30 3 25mm

40 3 35mm

32 3 15mm

Size of AC

negative (CT)

negative (CT)
positive (MR)

positive (MR)

positive (MR)

negative (MR)

positive (MR)
negative (MR)

positive (MR)

positive (MR)

negative (CT)

not clear (CT)

Radiologically
demonstrated
intracystic
hematoma

Hematoma irrigation

Hematoma irrigation
Hematoma irrigation

Hematoma irrigation

Hematoma irrigation

Hematoma irrigation

Hematoma irrigation
Hematoma irrigation

Hematoma irrigation

Hematoma irrigation

Hematoma irrigation

Hematoma irrigation

Treatment

Good

Good
Good

Good

Good

Good

Good
Good

Good

Good

Good

Good

Outcome

M, male; F, female; AC, arachnoid cyst; CP, cystoperitoneal; w, week; R, right; L, left; Galassi classification, Galassi et al. (1980); CT, computed tomography; MR, magnetic
resonance.

11/F

Age/sex

1

Patient
no.

Interval from
trauma to
operation of
CSDH

TABLE 1. CLINICAL CHARACTERISTICS OF 12 PATIENTS WITH CHRONIC SUBDURAL HEMATOMA ASSOCIATED WITH INTRACRANIAL ARACHNOID CYST

MORI ET AL.
TABLE 2. C OMPARISON OF PATIENTS WITH CHRONIC SUBDURAL HEMATOMA
WITH OR WITHOUT INTRACRANIAL ARACHNOID CYST
CSDH with AC
(n 5 12)

CSDH without AC
(n 5 529)

27.8 6 19.7

69.5 6 13.7

,0.001 (t test)

6; 6

376; 153

NS (x2 test)

Interval from trauma to operation
(week)

8.3 6 4.4

8.5 6 4.9

NS (t test)

Hematoma thickness (mm)

16.6 6 6.5

19.5 6 5.7

NS (t test)

Age (years)
Sex (male/female)

p value

Location of CSDH

Left
Right
Bilateral

41.7%
41.7%
16.6%

51.6%
30.8%
17.6%

NS (x2 test)

CT density of CSDH

High
Low
Iso
Niveau

58.3%
16.7%
25.0%
0%

19.5%
33.6%
27.6%
19.3%

,0.01 (x2 test)

Clinical symptoms

Gait disturbance
Hemiparesis
Headache
Dementia
Incontinence
Vomiting

8.3%
33.3%
83.3%
8.3%
0%
33.3%

63.5%
58.0%
37.4%
25.1%
17.6%
2.8%

,0.001 (x2 test)
NS
,0.05
NS
NS
,0.05

75.3 6 13.1

53.4 6 19.6

,0.01 (t test)

Reexpansion rate of CSDH (%)

Data are expressed as mean 6 standard deviation.
CSDH, chronic subdural hematoma; AC, arachnoid cyst; CT, computed tomography; t test, Student’s nonpaired t test; x2 test,
Pearson’s chi-square test; NS, not significant.

18 weeks previously. He showed no neurological deficits.
CT revealed a high density subdural hematoma in the
right frontal convexity but the presence of arachnoid cyst
in the right middle fossa (sylvian fissure) was not clear
because of the similar density to the CSDH (Fig. 1 upper). MR imaging clearly showed the arachnoid cyst in
the right sylvian fissure and the presence of the intracystic hematoma (Fig. 1 lower). The CSDH was irrigated
through burr holes and his symptoms disappeared.

Patient 5
A 39-year-old woman was admitted with right mild
hemiparesis following mild injury due to being struck by
her husband 9 weeks previously. CT showed a low density subdural hematoma and a small (16 3 10 mm) arachnoid cyst with an adjacent bony indentation in the left convexity (Fig. 2 upper). MR imaging showed intracystic

hematoma and continuity to the subdural hematoma (Fig.
2 lower). The CSDH was irrigated through two burr holes
and her symptom disappeared immediately afterward.
However, 4 years later she suffered headache and left
hemiparesis following mild head injury due to falling on
the road 8 weeks previously. CSDH had recurred on the
right, but the arachnoid cyst in the right convexity had not
changed. Her symptoms disappeared after burr hole irrigation. Unfortunately, she did not attend our outpatient
clinic after discharge, so we could not follow up the size
of the arachnoid cyst after the treatment for CSDH.

Patient 11
A 14-year-old boy was admitted with headache and
right hemiparesis following mild head injury due to
falling during physical training 4 weeks previously. CT
showed a high density subdural hematoma in the left

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CHRONIC SUBDURAL HEMATOMA ASSOCIATED WITH ARACHNOID CYST

FIG. 1. Patient 3. Upper: CT scans showing a high density subdural hematoma in the right frontal region and a high density
round mass lesion in the right sylvian fissure (arrow). Lower: MR images revealing the presence of blood in the arachnoid cyst
in the right sylvian fissure (arrow).

frontal and temporal region (Fig. 3 upper). CT also
showed a small bony indentation in the tip of the left middle fossa but the presence of arachnoid cyst was not clear
because of the intracystic hematoma. His symptoms disappeared immediately after CSDH evacuation through
burr holes. Postoperative MR imaging revealed a small
(15 3 7 mm) arachnoid cyst in the tip of the left middle
fossa (Fig. 3 lower). Follow-up MR imaging taken 4
months after the irrigation surgery showed that this small
arachnoid cyst had disappeared.

Patient 6
A 12-year-old boy was admitted with asymptomatic
arachnoid cyst in the right middle fossa. MR imaging

showed a Galassi type II arachnoid cyst in the right
middle fossa (Fig. 4 upper). The cyst had caused mass
effect to the surrounding brain. The cyst was opened
and communication formed between the cyst and the
basal cistern through right frontotemporal craniotomy
on March 24, 1994. Postoperative MR imaging taken
1 week after the surgery showed formation of bilateral
thin subdural effusions (Fig. 4 middle). Follow-up MR
imaging taken 11 weeks after the cyst opening revealed
the formation of CSDH on the right and compression
of the right lateral ventricle (Fig. 4 lower). The patient
was symptom-free. The hematoma was irrigated
through two burr holes and he was discharged without
complications.

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MORI ET AL.

FIG. 2. Patient 5. Upper: CT scans showing a low density subdural hematoma in the left frontoparietal region and a small
arachnoid cyst with an adjacent bony indentation in the left frontal convexity (arrow). Lower: MR images revealing the presence
of blood in the arachnoid cyst (arrow).

DISCUSSION
The etiology of CSDH is not completely understood.
Traumatic subdural effusion is widely accepted as a precursor stage in the formation of CSDH (Ohno et al., 1987;
Murata, 1993). Arachnoid tear is also accepted as a
causative factor in the development of traumatic subdural
effusion (Naffziger, 1924; Stone et al., 1981), supported
by the observation that CSDH tends to occur in elderly
people because brain atrophy causes enlargement of the
subarachnoid space and stretching of the bridging veins,
and these preexisting conditions facilitate tearing of the
arachnoid membrane and leakage of bloody cerebrospinal
fluid (CSF) into the subdural space after mild head in-

jury (Markwalder, 1981). CSF with or without blood
leaks into the subdural space then facilitates the formation of the “outer membrane” under the dura mater, which
forms internal capillaries or sinusoids (Yamashita and
Yamamoto, 1984; Hasegawa et al., 1992). These blood
vessels in the outer membrane are fenestrated and allow
plasma fluid leakage and resultant enlargement of the
subdural effusion (Sato and Suzuki, 1975; Mori et al.,
1996, 1998; Mori and Maeda, 2000). Bleeding then occurs repeatedly from the capillaries with degenerating endothelium accompanied by local hyperfibrinolysis, which
is one of the causes of the development of effusions into
CSDH (Ito et al., 1976, 1978).
Arachnoid cyst is also known to be a predisposing fac-

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CHRONIC SUBDURAL HEMATOMA ASSOCIATED WITH ARACHNOID CYST

FIG. 3. Patient 11. Upper: CT scans showing a high density subdural hematoma in the left frontal region, and a small bony indentation in the tip of the left middle fossa. Lower: Postoperative MR images revealing the presence of a small arachnoid cyst
in the tip of the left middle fos

tor for CSDH after mild head injury. Arachnoid cysts are
generally believed to be congenital whereas CSDHs tend
to occur in elderly people. Association of these two distinct clinical entities indicates involvement in the etiology of CSDH. Arachnoid cyst is occasionally associated
with subdural effusion, which is generally thought to result from tearing of the outer wall of the arachnoid cyst
after head injury (Albuquerque and Giannotta, 1977;
Parsch et al., 1997). The rupture of arachnoid cyst can
even occur spontaneously (Rakier and Feinsod, 1995).
Tearing of the outer wall of the arachnoid cyst is associated with subdural and/or intracystic hemorrhage caused
by rupture of bridging veins, unsupported blood vessels
around the cyst wall, and leptomeningeal vessels in the

base of the cyst (Galassi et al., 1980; Aoki and Sakai,
1990). The present study found no neuroimaging evidence of intracystic hematoma in five of the 12 cases,
but we cannot exclude the presence of slight intracystic
bleeding undetected by CT or MR imaging in these five
cases. Communication of the cyst, and CSDH through
the tear in the arachnoid cyst wall has been identified by
intraoperative findings and technetium-99m scintigraphy
(Galassi et al., 1980; Yokoyama et al., 1989). Animal experimental studies have shown that CSF and blood fibrin in the subdural space form an active fibroblastic membrane (premature outer membrane) beneath the dura
mater (Watanabe et al., 1972; Apfelbaum et al., 1974).
These observations support the importance of arachnoid

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MORI ET AL.

FIG. 4. Patient 6. Upper: MR images showing a Galassi type II arachnoid cyst in the right middle fossa. Middle: Postoperative MR images at 1 week after cyst opening revealing the formation of bilateral thin subdural effusions (arrowheads). Lower:
Follow-up MR images at 11 weeks after surgery showing a chronic subdural hematoma in the right frontal region.

tearing as an initial factor in the formation of CSDH. The
most common lesion is CSDH ipsilateral to the arachnoid cyst, but CSDH may occur bilaterally or even contralaterally (Page et al., 1987; Parsch et al., 1997). The
present study demonstrated the occurrence of CSDH associated with arachnoid cyst, followed by the formation
of bilateral subdural effusions after cyst opening in the
middle fossa. These bilateral subdural effusions might be
the reason why arachnoid cyst is sometimes associated
with the formation of bilateral or even contralateral
CSDH. The present series included two cases of bilateral
CSDHs and one case of contralateral CSDH, as well as
cases of CSDH associated with arachnoid cyst in the pos-

terior fossa. Bilateral and contralateral CSDH were found
in two of seven cases of arachnoid cyst in the middle
fossa. The arachnoid cyst is less compliant than normal
brain and so provides reduced intra-calvarial cushioning
following minor trauma, and consequently hemorrhage
is likely to occur from the ipsilateral or contralateral
bridging veins resulting in bilateral or contralateral
CSDH (Page et al., 1987). The association of CSDH and
arachnoid cyst in the posterior fossa might be a coincidence. This study is not conclusive and the subject needs
further investigation.
CSDH is generally believed to occur in elderly patients
(Markwalder, 1981). Our series of 541 patients with

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CHRONIC SUBDURAL HEMATOMA ASSOCIATED WITH ARACHNOID CYST
CSDH included only eight pediatric patients (1.5%) with
CSDH, and five of these pediatric cases (62.5%) had associated arachnoid cyst. The high incidence of association with arachnoid cyst in pediatric cases was statistically significant. This observation clearly shows that
arachnoid cyst is a risk factor of CSDH in pediatric or
young patients. Indeed, tearing of the arachnoid cyst wall
after head injury may be a causative factor of CSDH in
children. Physicians should give this information to patients with arachnoid cyst and warn them to avoid sports
such as boxing and football that have a high incidence of
head injury.
Patients with CSDH associated with arachnoid cyst
most frequently present with symptoms of increased
intracranial pressure (Arai et al., 1996; Parsch et al.,
1997; Albuquerque and Giannotta, 1997). In the present study, the most common symptom of patients with
CSDH without arachnoid cyst was gait disturbance followed by hemiparesis. In contrast, the most common
symptoms of patients with CSDH and arachnoid cyst
were headache and vomiting. Headache is more common in young patients because they tend to suffer increased intracranial pressure caused by CSDH. Conversely, if patients with asymptomatic arachnoid cyst
show signs of increased intracranial pressure after head
injury, the complication of CSDH should be considered (Albuquerque and Giannotta, 1997; Parsch et al.,
1997).
Most cases of arachnoid cyst with CSDH have occurred in the middle fossa. In the present series, eight
of 12 cases (67%) were located in the middle fossa (sylvian fissure), six of which were Galassi type I and relatively small. The smallest was 15 3 7 mm and could
be recognized only by MR imaging. Another case of
small (16 3 10 mm) arachnoid cyst in the convexity
caused two episodes of CSDH after different head injuries. Even small arachnoid cyst in the middle fossa
and also the convexity may be a predisposing factor for
CSDH. Repeat CT may be required in young patients
with CSDH if CT diagnosis is impaired by an isodense
arachnoid cyst due to the presence of intracystic
hematoma (Hara et al., 1984; Page et al., 1987;
Yokoyama et al., 1989). In the present study, the intracystic hematoma was demonstrated radiologically in 6
cases. Furthermore, we recommend MR imaging to detect the presence of small arachnoid cyst in young patients with CSDH.
The treatment of CSDH associated with arachnoid
cyst is still controversial. Immediate removal of the
membrane of the arachnoid cyst and evacuation of the
subdural fluid by craniotomy is recommended (Galassi
et al., 1980). In the present series, we performed only

hematoma evacuation through burr holes, except for
one case with cystoperitoneal shunting, and the symptoms disappeared in all cases. Spontaneous disappearance or decreased size of the arachnoid cyst after
hematoma evacuation does occur (Mori et al., 1995;
Rakier and Feinsod, 1995; Albuquerque and Giannotta,
1997). In our cases, such spontaneous reduction of
arachnoid cyst after burr hole irrigation was observed.
Cyst removal or fenestration at the time of drainage of
CSDH is unnecessary in cases of previously asymptomatic arachnoid cyst (Parsch et al., 1997). Most symptoms of CSDH associated with arachnoid cyst are due
to increased intracranial pressure. Therefore, we recommend only burr hole irrigation of CSDH without
cyst opening at the first operation (Oka et al., 1994;
Arai et al., 1996; Parsch et al., 1997). If the preoperative symptoms persist after the evacuation of the
CSDH, additional surgery to treat the arachnoid cyst
should be considered.
The number of cases of development of subdural
hematoma in patients with arachnoid cysts of the middle fossa has increased since the first report (Robinson,
1971). The real incidence of arachnoid cyst complicated by CSDHs and hygromas is not clear. Sixteen
cases (2.4%) of associated arachnoid cysts were found
among 658 cases of CSDHs and hygromas (Parsch et
al., 1997). The present series included 12 cases with
arachnoid cyst among 541 cases of surgically treated
CSDHs (2.2%). Therefore, arachnoid cyst can only be
recognized in 2% of cases of CSDHs. Conversely,
8–17% of cases of arachnoid cyst are complicated by
subdural hematoma or hygroma after head injury
(Hayashi et al., 1979; Galassi et al., 1980; Arai et al.,
1996). Therefore, the association of subdural hematoma
is not uncommon. Most cases of arachnoid cyst with
CSDH are located in the middle fossa. Our series also
showed that the middle fossa is the most frequent site
for arachnoid cyst with CSDH. We think that the middle fossa is the most common site for arachnoid cyst
because this location is rich in unsupported veins such
as the superficial middle cerebral veins that easily bleed
after head injury. However, we also found that small
arachnoid cyst in the convexity and even in the posterior fossa could also cause CSDH formation in young
patients. We should inform patients with arachnoid cyst
and their families of the possibility of complication
with CSDH and advise care to avoid head injury in
daily life regardless of the size and location of the cyst.
However, we do not recommend surgical treatment for
arachnoid cyst to prevent CSDH, because the present
study included two cases of CSDH formation after
arachnoid cyst surgery.

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MORI ET AL.

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Address reprint requests to:
Kentaro Mori, M.D., Ph.D.
Department of Neurosurgery
Juntendo University Izunagaoka Hospital
1129 Nagaoka, Izunagaoka-cho, Tagata-gun
Shizuoka 410-2295, Japan

YOKOYAMA, K., TONAMI, N., KIMURA, M., et al. (1989).
Scintigraphic demonstration of intracranial communication

E-mail: KMORI1919@hkg.odn.ne.jp

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