Department of Neurosurgery, Provincial Tao-Yuan
General Hospital,Taiwan, Tao-Yuan, Republic of
China
Neurosurgery 32; 498-504, 1993
ABSTRACT: THE MICROSURGICAL EXCISION
of arteriovenous malformations located in the
thalamic region in eight patients is reported. Six were
located in the posterior aspect of the thalamus and
two were located in the anterior. Hemorrhage
occurred in all of the cases. Hemiparesis,
hemianesthesia, and consciousness disturbance were
the most typical clinical features. The supine position
with the anterior transcallosal approach was used for
anterior dorsal lesions, and the sitting position with
the posterior interhemispheric approach was used for
posterior dorsal lesions. Total removal was confirmed
by angiography in seven patients, and incomplete
removal was noted in one patient. There was one
death in this group of patients. Memory disturbance
was the most common postoperative complication.
This complication showed considerable improvement
with time. Other complications included
homonymous hemianopsia (three patients),
hemisensory loss (six patients), and transient
hemiparesis (one patient). All survivors (seven
patients) were able to return to their occupation after
surgery. The vascular input, the location of the
malformation, and clinical history are the
contributory factors concerning operability. With the
modern neurosurgical and anesthesiological facilities,
surgical removal of thalamic malformations in
selected cases is advisable.
KEY WORDS: Arteriovenous malformation;
Intracerebral hemorrhage; Surgical excision;
Thalamus
Arteriovenous malformations (AVMs) in the
thalamus have been considered inoperable. However,
rupture of an AVM in this location can lead to
catastrophic parenchymal or intraventricular
hemorrhage. Thus, an untreated thalamic AVM is
considered a hazardous entity. Having gained
experience from operating on callosal, parasplenial
AVM and having familiarity with the topographic
anatomy of the thalamic region, surgical intervention
for the thalamic AVM was done in selected cases.
The presentation, surgical technique, indication, and
outcome of these cases are detailed.
SUMMARY OF CASES
This series of eight patients includes three males
and five females. Their ages ranged from 9 to 38
years (mean, 25.6 yr). Clinical symptoms and signs

LOCATION OF THE ARTERIOVENOUS
MALFORMATION
All of these AVMs were primarily located in the
thalamus: four on the right side and four on the left
side. The majority of AVMs (n = 6) were located on
the posterior aspect of the thalamus. Two AVMs were
located in the anterior aspect of the thalamus
(Table 1).
VASCULAR ANATOMY
Although most malformations in this series were
supplied by two or more major arteries, the
thalamoperforator is the primary vascular supply
(Table 3). All malformations were fed by the
thalamoperforator. Four of those also received input
from the anterior choroidal artery, and the posterior
choroidal artery was involved in seven patients. The
lenticulostriate artery was angiographically
demonstrated to supply only two malformations.
The venous drainage from these malformations was
always toward the midline. In three patients, the
primary draining vein was into the basal vein of
Rosenthal. In the remaining five patients, the venous
drainage was directly into the internal cerebral vein.
SURGICAL TECHNIQUE
The supine or sitting position is used depending on
the exact site of the lesion. The supine position with
anterior transcallosal approach is used for anterior
dorsal AVMs, and the sitting position with posterior
interhemispheric approach is used for posterior dorsal
AVMs. For the anterior transcallosal approach, the
patient is positioned in the recumbent supine
position, with the head flexed so that the junction of
the coronal and sagittal sutures is parallel to the
horizontal. An ipsilateral procedure is used. A free
bone flap is elevated, making the superior margin just
to the left of the midline so that the sagittal sinus is
exposed. The anteroposterior position of the flap is
situated so that two- thirds will be anterior to the
coronal suture and one-third will be posterior. The
dura is then opened in a U-shaped fashion, with the
base along the sagittal sinus. When the medial margin
of the hemisphere is free, gentle retraction is applied
to separate it from the falx. The gyri of the right and
left cingulate region often adhere to each other and
must be separated. The corpus callosum is divided
over a distance of about 2 to 3 cm. The ipsilateral
ventricle is then entered. At this point in the
operation, some aspect of the malformation with
hemorrhage may be visualized (Fig. 1). The thalamus
will then be explored lateral or medial to the choroid
plexus depending on the position of the drainage vein
and on the surface of the thalamus. If a local
hematoma is evident, the hematoma is removed first
and then the pathological vessel is dissected along the

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AUTHOR(S): Lee, Jen-Pei, M.D.

are summarized in Table 1. Hemorrhage occurred in
all patients; it occurred twice in one patient and three
times in two patients. One patient also had focal
seizures when the bleeding occurred. Clinical
findings of hemiparesis, hemianesthesia, and
consciousness disturbance appear to be the most
typical features of this lesion (Table 2).

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Neurosurgery 1992-98
April 1993, Volume 32, Number 4
498 Surgical Treatment of Thalamic Arteriovenous
Malformations
Clinical Study

ILLUSTRATED CASES
Patient 1
This 18-year-old girl experienced a sudden onset of
severe headache and vomiting 8 months before the
time of admission. A similar episode with
consciousness disturbance brought her to our
emergency service. An examination revealed that she
was in a comatose state, with a Glasgow Coma Scale
score of E1M4V1, isocoric pupil with normal light
reflex, neck stiffness, left hemiplegia, and
hemianesthesia. A generalized tonic-clonic seizure
was noted in the emergency room. A computed
tomographic scan showed hemorrhage in the right
thalamus with rupture into the ventricle. Emergent
ventricular drainage was done. She gradually

Patient 2
This 9-year-old boy was brought to our hospital
because of sudden onset of headache and vomiting
associated with consciousness disturbance. An
examination revealed a Glasgow Coma Scale score of
E1M5V1, isocoric pupil with normal light reflex,
neck stiffness, right hemiplegia, and hemianesthesia.
A computed tomographic scan showed left thalamic
hemorrhage with rupture into the ventricle. After
conservative treatment, he regained consciousness. A
cerebral angiogram was arranged and revealed an
AVM in the left pulvinar region with feeders from the
thalamoperforators and posterior choroidal artery and
drainage to the internal cerebral vein (Fig. 5).
The first operation was performed by an anterior
interhemispheric approach. After the corpus callosum
was divided, the left lateral ventricle was entered. An
area of old hemorrhage facilitated the identification
and dissection of the malformation. The
malformation was located in the posterior dorsal
aspect of the thalamus. It was excised
circumferentially. We found it difficult to give
adequate management of the entire malformation
through this approach. The follow-up angiogram
disclosed some residual AVM (Fig. 6). The second
procedure was performed 3 weeks later. The occipital
interhemispheric approach with the patient in the
sitting position was used. The occipital lobe was
retracted laterally. After identification of the
splenium, the corticotomy was made on the
precuneus. The trigone was then entered, and the
malformation could be identified through the floor of
the trigone. By use of an operating microscope, the
malformation was dissected around the margin. The
lesion was easily excised. The postoperative
angiogram revealed complete obliteration of the
malformation (Fig. 7). The patient's postoperative
recovery was uneventful. Six months after the
operation, only mild hyperreflexia over the right arm

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SURGICAL OUTCOME
Two patients in this series underwent the anterior
transcallosal approach, and four patients received the
posterior interhemispheric approach. The remaining
two patients required the anterior and posterior
approach in two procedures. All patients except one
had total removal (Table 4). The only patient with
incomplete excision died. The other seven patients
were able to resume their previous occupations after
surgery. The most common postoperative
complication was a disturbance of recent memory.
Five patients were noted to have at least transient
problems in acquiring new knowledge. However, four
of these patients had suffered a preoperative memory
disturbance as a result of hemorrhage. All patients
showed considerable improvement with time.
Three patients were found to have a contralateral
homonymous field defect after the operation. All of
these patients had field cut preoperatively. There
were six cases of postoperative hemisensory loss, but
only three persisted. One patient had transient
hemiparesis, and he regained normal strength in 1
month.
All eight patients were studied with postoperative
angiography. Total removal of the AVM was
confirmed in five patients, and residual AVM was
noted in three. Subsequent operations with total
obliteration were required in two of these three
patients. Unfortunately, the other did not have a
chance for another operation because of continued
bleeding, resulting in death 5 days after the initial
operation.

regained consciousness. A cerebral angiogram
demonstrated a small AVM in the right anterior
thalamic region with feeding vessels from the anterior
and posterior choroidal arteries and the
thalamoperforators (Figs. 3A and 4A).
The operation was performed through a right,
frontoparietal craniotomy with the patient in the
supine position. Via the anterior interhemispheric
route, the corpus callosum was divided to about 2 cm
in distance. The right lateral ventricle was then
entered. An old blood clot was noted in the floor.
After the clot was removed, the AVM was
encountered in the anterior dorsal aspect of the
thalamus. A circumscribing incision was made
around the malformation, and the dissection was
gradually deepened. After total occlusion of the
feeder, the malformation was removed.
A postoperative angiogram revealed no residual
malformation (Figs. 3B and 4B). The patient
experienced progressive improvement after the
operation. At her 6-month follow-up examination,
she had normal neurological status except for mild
hyperreflexia on the left side. She had returned to
work and her usual activities.

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cleavage plane of the malformation. The elimination
of the feeders always causes some difficulties, which
can be overcome with patient stepwise dissection,
coagulation, separation, and further dissection.
For the posterior interhemispheric approach, the
patient is placed in the sitting position. Through a
parasagittal, parieto-occipital craniotomy, exposure
continues in an interhemispheric plane along the
parasplenial region, with splitting of the ipsilateral
paramedian corpus callosum for 1 cm anterior to the
splenium and entering into the trigone (Fig. 2). The
exploration may also extend through the posterior
part of the trigone; then, the same technique for the
excision of anterior thalamic malformations is
continued.

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DISCUSSION
Operative resection of AVMs in the thalamus is a
great challenge for the neurosurgeon. These vascular
malformations are located deep within the brain
substance adjacent to several vital structures of the
central nervous system. It can be expected that
surgery for these lesions may lead to profound and
disabling neurological sequelae. Solomon and Stein
(11)
and Shi and Chen (9) have reported good success,
but the AVMs in the basal ganglion and ventricle are
included in their series. The AVMs reported here are
primarily located in the thalamus. This retrospective
analysis also indicated that the AVMs in the thalamus
can be safely removed in selected cases by current
surgical techniques.
The preoperative preparation for these patients
requires detailed neuroradiological studies. Highresolution computed tomographic scanning and, more
recently, magnetic resonance imaging have proved
invaluable for the precise localization of the AVMs
and for defining their relationship to the tentorium,
the brain stem, and the ventricular system. Cerebral
angiogram is indispensable when planning the
surgical approach, and it is essential to understand the
vascular anatomy.
The primary input in all of the AVMs in this series
was from the thalamoperforators; this is characteristic
of AVMs involving the thalamus. The patients
reported by Solomon and Stein (11) had primary
vascular supply from the choroidal arteries. The
thalamoperforating arteries were angiographically
demonstrated to supply only three malformations.
The majority of cases reported by Shi and Chen (9)
received input from the anterior choroidal artery and
the lenticulostriate artery. The perforating branches of
the posterior cerebral artery and the posterior
communicating artery were noted in only one patient.
The AVMs in the basal ganglion and ventricle are
also included in their series. We suggest that the
primary input of AVMs in the thalamus is restricted
to the thalamoperforating arteries.
Embolization has been a useful adjuvant to the
surgical treatment of large, supratentorial AVMs (13);
however, the malformations in the thalamus are
generally not suitable for this procedure. These
malformations are primarily supplied by the
thalamoperforating arteries, choroidal arteries, and
lenticulostriate arteries. These vessels generally have
small intraluminal diameters and arise from parent
vessels at right angles. These factors make
embolization hazardous and not usually indicated for
these malformations.
The interhemispheric transcallosal approach was
first described by Dandy (1) for removing posterior
third ventricle tumors. It had been applied for treating
vascular malformations in the medial hemisphere (12)
and following the tentorial ring (10). We used the same
approach but put the craniotomy more anteriorly. We
found it ideal for treating vascular malformations in
the region of the anterior thalamus. The AVMs can be
easily localized after the hematoma in the floor of the

ventricle is identified. For vascular malformation in
the posterior thalamus, the posterior interhemispheric
approach was used. The patient was placed in the
sitting position. The exposure was then done in the
interhemisphere plane through a parasagittal, parietooccipital craniotomy. The trigone can be entered after
the paramedian corpus callosum has been split
anterior to the splenium. The malformation can also
be localized after the hematoma in the floor of the
ventricle has been identified.
Soloman and Stein (11) used the interhemispheric
transcallosal approach for treating vascular
malformations in the region of the atrium of the
lateral ventricle. The hemisphere retraction was
usually on the parietal lobe. The bridging vein
represents a hazard of this approach, and it may be
necessary to take one or two sizable draining veins.
We put the hemisphere retraction on the parietooccipital region for treating lesions around the
posterior thalamus. The bridging veins usually are
lacking around there. The transcortical,
transventricular approach for the excision of the
thalamic malformations has also been reported.
Different corticotomies via the parietal lobe (4), the
superior temporal gyrus (2), the middle temporal gyrus
(15)
, or the inferior temporal gyrus (3) have been
applied. The major drawback to those approaches is
that normal functioning brain must be traversed
before the malformations are reached. In addition, the
exposure is usually away from the deep arterial
supply.
The surgical indications for thalamic
malformations are still controversial. We restricted
the operative cases to those who had a history of
bleeding. Problems in localizing the vascular
malformation will be met in those without a history
of bleeding, and surgery could result in disastrous
sequelae. The vascular input also contributes to the
indications. Primary vascular input from the anterior
thalamoperforator may not be a good candidate
because of the high possibility of hypothalamus
involvement. Primary input from the posterior
thalamoperforator, choroidal, or lenticulostriate
arteries are more optimal. Dorsal, posterior, or lateral
locations are easier to approach. Lesions located
mainly on the ventral region involve more risk
because of deep position and possibility of
hypothalamus involvement. All of the cases reported
here fitted these criteria.
The most common postoperative complication was
a disturbance in recent memory. Five of the patients
with thalamic malformations in this series were found
to have problems in acquiring new knowledge.
However, four of these patients had suffered a
preoperative memory disturbance consequent to
AVM rupture. Those malformations were all located
on the left side. Only one additional patient with right
thalamic AVM displayed memory disturbance after
surgery. Solomon and Stein (11) had the same
findings, and they suggested that the left fornix,
thalamus, and/or caudate nucleus are critical for
recent memory function.
Gamma-beam irradiation for the treatment of small
AVMs has been advocated by Steiner (14). The

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and right homonymous hemianopsia were present. He
had returned to his previous occupation as a student.

Received, May 27, 1992.
Accepted, October 28, 1992.
Reprint requests: Jen-Pei Lee, M.D., Department
of Neurosurgery, Provincial Tao-Yuan General
Hospital, 1492, Chung-Shan Road, Tao-Yuan Taiwan
33007, Republic of China.

7.

8.

9.

10.

11.

12.
13.

14.

15.

Wilkins 1984, pp 12-23.
Pellettieri L, Carlsson CA, Grevsten S, Norlen
G, Uhlemann C: Surgical versus conservative
treatment of intracranial arteriovenous
malformations. A study in surgical decisionmaking. Acta Neurochir (Wien) Suppl
29:86, 1980.
Perret G: The epidemiology and clinical
course of arteriovenous malformations, in Pia
JRW, Gleave E, Grote JZ (eds): Cerebral
Angiomas. Berlin, Springer, 1975, pp 21-26.
Riechert T: Stereotactic treatment of central
angiomas, in Pia JRW, Gleave E, Grote JZ
(eds): Cerebral Angiomas. Berlin, Springer,
1975, pp 129-135.
Shi YQ, Chen XC: Surgical treatment of
arteriovenous malformations of the
striatothalamocapsular region. J Neurosurg
66:352-356, 1987.
Solomon RA, Stein BM: Surgical
management of arteriovenous malformations
that follow the tentorial ring. Neurosurgery
18:708-715, 1986.
Solomon RA, Stein BM: Interhemispheric
approach for the surgical removal of
thalamocaudate arteriovenous malformations.
J Neurosurg 66:345-351, 1987.
Stein BM: Arteriovenous malformations of
the medial cerebral hemisphere and the limbic
system. J Neurosurg 60:23-31, 1984.
Stein BM, Wolpert SM: Arteriovenous
malformations of the brain II. Current
concepts and treatment. Arch Neurol 37:6975, 1980.
Steiner L: Treatment of arteriovenous
malformations by radiosurgery, in Wilson CB,
Stein BM (eds): Intracranial Arteriovenous
Malformations. Baltimore, Williams &
Wilkins, 1984, pp 295-313.
U HS: Microsurgical excision of
paraventricular arteriovenous malformations.
Neurosurgery 16:293-303, 1985.

REFERENCES: (1-15)
1.
2.

3.

4.

5.

Dandy E: Diagnosis, localization and removal
of tumors of the third ventricle. Bull Johns
Hopkins Hosp 33:188-189, 1922.
Drake CG: Cerebral arteriovenous
malformations: Considerations for and
experience with surgical treatment in 166
cases. Clin Neurosurg 26:145-208, 1979.
Heros RC: Arteriovenous malformations of
the medial temporal lobe. Surgical approach
and neuroradiological characterization. J
Neurosurg 56:44-52, 1982.
Juhasz J: Surgical treatment of arteriovenous
angiomas localized in the corpus callosum,
basal ganglia, and near the brain stem. Acta
Neurochir 40:83-101, 1978.
Luessenhop AJ: Natural history of cerebral
arteriovenous malformations, in Wilson CB,
Stein BM (eds): Intracranial Arterovenous
Malformations. Baltimore, Williams &

COMMENTS
The author presents a timely article that discusses
the microsurgical obliteration of deep (thalamic)
arteriovenous malformations (AVMs). Currently,
there is raging discussion about the benefits of
radiosurgery for these lesions as opposed to
microsurgical removal. Solomon and Stein (1) have
previously discussed the microsurgical treatment of
small AVMs, including those located in the thalamus.
We had approximately an 85% cure rate in these
lesions, with no mortality and no major neurological
permanent deficits. Lee has approximately an 88%
cure rate but unfortunately a 12% mortality. It is
interesting that in order to salvage this cure rate,
further operations were necessary on two patients for
residual malformations left at the time of the first
surgery. Without including the mortality rate in this
article, the cure rates of Solomon and Stein and Lee
are higher than those obtained by radiosurgery.
I found the surgical judgment and discussion

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ACKNOWLEDGMENT
The author expresses his thanks for Miss Yun Shu
for her excellent secretarial assistance.

6.

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successful treatment of a large group of patients has
been reported with complete obliteration of the
malformations. The major drawback to this method is
the long latent period between the treatment and
obliteration of malformations and the risk of
hemorrhage during that period. Additionally, the longterm deleterious effect of this high-energy radiation is
unknown. Therefore, radiosurgery can only be
considered in patients with AVMs that have not
ruptured and that are situated in a location
unfavorable for surgical removal.
There are no reports of thalamic malformations that
can clarify the relative merits of surgical excision
versus conservative treatment, nor are there specific
elements in individual cases that would suggest a
good or bad prognosis. On the other hand, patients
with deep-seated angiomas appear to be prone to
recurrent hemorrhage (6-8). Surgical intervention
seems advisable, provided that operative mortality
and morbidity can be expected to be lower than that
expected from the natural course. Compared with the
risk of morbidity due to an untreated AVM, which
approaches 50% (5,13), only one patient in this series
died. Surgical excision of ruptured thalamic
malformation is warranted. In conclusion, with the
use of modern operative and anesthesiological
facilities, the surgical treatment of thalamic
malformations in selected cases has become not only
possible but even advisable in view of the low
morbidity when compared with the risk of alternative
or conservative treatment.

Bennett M. Stein
New York, New York
REFERENCES: (1)
Solomon RA, Stein BM: Interhemispheric
approach for the surgical removal of
thalamocaudate arteriovenous malformations.
J Neurosurg 66:345-351, 1987.

Dr. Lee is to be commended for managing this
group of thalamic AVMs with very acceptable
morbidity and mortality. This article promises to
provoke controversy in an era when more and more
ruptured thalamic lesions are being referred for
stereotactic radiotherapy. The surgical principles
described in this report are anatomically based and
appear to be quite sound. I would disagree with two
specific points articulated by the author.
The first point concerns the delay in definitive
surgical resection after an initial incomplete surgical
procedure that did not result in complete removal.
The only mortality of this series occurred 5 days after
the first procedure because of a subsequent bleeding
episode. I also noted that in Patient 2, a second
operation was delayed 3 weeks. It has been our
experience that the initial surgical procedure
invariably alters the dynamics of the venous drainage,
and if the resection is incomplete, immediate risk is
imposed by this dangerous de-efferentation. Our
policy of definitive immediate postoperative
angiography with the patient under anesthesia, with a
return to the operating room if residual is noted, was
born from such catastrophes. The second point
concerns the value of superselective embolization in
thalamic and other eloquently located malformations.
These are the very malformations in which a
relatively dry and thoroughly embolized dissection
plane is the most desirable, as one dissects tightly
along the margin using generous coagulation to
withdraw the AVM from vital tissue. If robust
feeding to the malformation is left intact at the time
of operation, the tiny fragile vessels at the periphery
rupture easily and require transgression into
important tissue to secure hemostasis. Although there
are technical difficulties in accessing some of these

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1.

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thereof as well as the approaches to be well founded
and solid. He points out many of the nuances of the
surgical approach to these lesions and the anatomical
angiographic evaluation before surgery.
I was particularly interested in the discussion of
recent memory difficulties after this surgery, some of
which were present before the operation. He pointed
out, as we did, that this is more apt to occur when the
lesion is located on the left side, suggesting some
dominance in the acquisition of facts or recent
memory. This lends further credence to that theory of
a dominance of this system. In general, I agree with
everything that was presented but am chagrined by
the relatively high mortality figure.

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Figure 1. Artistic drawing of the anterior
interhemispheric approach to the ventricle through
the division of the corpus callosum. Retractor is
shown on the medium surface of the frontal lobe. The
vascular malformation can be seen beneath the
ependyma of the ventricle.

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Figure 3. A, anteroposterior carotid angiogram of
Patient 1 preoperatively, showing an AVM fed by the
anterior choroid artery and drained by a vein to the
basal vein of Rosenthal. B, postoperative angiogram
showing no evidence of residual AVM.

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Figure 2. Artistic drawing of the left posterior
interhemispheric approach to the trigone through an
incision in the precuneus. The vascular malformation
can be identified beneath the floor of the trigone

Figure 6. Lateral vertebral angiogram (performed
postoperatively) showing some residual AVM.

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Figure 5. Lateral vertebral angiogram showing
prominent vascular supply by thalamoperforator and
posterior choroidal arteries and the draining vein to
the internal cerebral vein

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Figure 4. A, lateral vertebral angiogram of Patient 1
preoperatively, showing prominent vascular supply
by posterior choroidal arteries and
thalamoperforators. B, postoperative angiogram
showing total occlusion of the AVM

Table 2. Symptoms and Signs of Patients with
Thalamic Arteriovenous Malformations

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Table 1. Summary of Eight Patients with Thalamic
Arteriovenous Malformations

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Figure 7. Lateral vertebral angiogram (after second
operation) showing no evidence of residual AVM.

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Table 4. Operative Results of Eight Patients with
Thalamic Arteriovenous Malformations

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Table 3. Vascularization of Eight Patients with
Thalamic Arteriovenous Malformations