!!!pontine cavernoma

Clinical ArticlesFunctional Results After Microsurgical Resection of Brain Stem CavernousMalformations (Retrospective Study of a 12 Patient Series and Review of theRecent Literature)

M. Sindou1, J. Yada1, and F. Salord1

1 Department of Neurosurgery, HoÃpital Neurologique, P. Wertheimer, University of Lyon, France

2 Department of Anesthesiology, HoÃpital Neurologique, P. Wertheimer, University of Lyon, France

Summary

Background. Since advent of MRI, brain stem Cavernous Mal-

formations (CM) can be easily diagnosed, and their curative surgical

resection considered under precise conditions. The authors report a

consecutive series of twelve patients with CMs surgically treated and

histopathologically con®rmed. Eleven of the cases had bled (six more

than once). In this study special emphasis has been put on the pre and

post-operative functional status of the patients, by using the 100

Karnofsky scale (KS).

Method. Surgical approaches were: 1�) supra-occipital trans-

tentorial for 1 thalamomesencephalic and 1 quadrigeminal plate

CM, 2�) suboccipital infratentorial supracerebellar for 1 dorsolateral

mesencephalic CM, 3�) retrosigmoid through the cerebello-pontine

angle for 3 pontine and/or medullary CM, 4�) suboccipital inter-

tonsillar for 6 CM located under the ¯oor of the IVth ventricle.

Completeness of removal was checked by postoperatoire MRI. It

was complete in 11 cases and only partial in 1 (i.e., in the case with

the progressing mass-eëct presentation). There was no post-op

death. Follow-up ranged from 1 to 7 years.

Findings. Preoperatively: 2 patients were operated on in a coma-

tose state (KSU 20), 5 were in state of functional dependance

(KU 60) and 5 had severe neurological de®cits but were still of

independant functional status (KSV 60). At one year after surgery:

3 patients had a KSV 80 (i.e., they could resume their prior normal

life), 6 had a KS between 60 and 80 (i.e., they were independant)

and 3 had a KS below 60 (i.e., they were dependant especially for

walking).

Interpretation. Our results, as well as the data harvested from the

literature, plead for advocating radical surgical resection at least in

patients with exophytic CMs having bled. As a matter of fact, study

of the natural history shows that in brain stem CMs, the bleeding risk

amounts to 21% per year per patient. Review of literature shows

evidence that radiosurgery did not prove eëctive and/or even

innoccuous.

Keywords: Brain stem; cavernoma; Cavernous Malformation;

microsurgical removal.

Introduction

The diagnosis of brain stem Cavernous Malforma-

tions (CMs) has greatly bene®ted from the advent of

MRI. This tool facilitated the identi®cation and survey

of this lesion even in pauci-symptomatic lesions, which

helped to study the natural history of these malforma-

tions. According to data in the literature [8, 9, 10, 14,

17, 21, 27, 31, 35], brain stem CMs account for 17% on

average of all symptomatic intracranial CMs, with an

extreme of 35% in the study on natural history of CMs

by Kondziolka et al. [14].

If considering overall intracranial CMs, the risk of

bleeding is 0.5% per year for cavernomas which have

not bled and 4.5% per year for those that have already

bled [7, 22]. For brain stem CMs, the annual rate of

hemorrhagic risk is much higher [1, 5, 9, 10, 14, 18, 24,

35]; in Fritschi et al 's article [9] it has been estimated

at 2.7% for a patient without a prior bleed and at 21%

for a patient with previous hemorrage. In the surgical

series of Porter et al. [21] 97 of the 100 patients referred

had bled. 54 of these 97 patients (56%) had multiple

hemorrhages and 21 of them (22%) had more than two

hemorrhages.

Growth evolution with mass-eëct and/or repeated

hemorrhages almost constantly result in irreversible

severe neurological de®cits. In a retrospective study of

a group of 30 patients treated conservatively [9], mor-

tality rate amounted to 20%.

Acta Neurochirurgica> Springer-Verlag 2000Printed in Austria

Acta Neurochir (Wien) (2000) 142: 843±853

Because it appeared that microsurgical techniques

could render surgical resection of CMs feasible at the

brain stem, an increasing number of neurosurgeons

in the nineties started to treat symptomatic brain stem

CMs surgically, especially those with a super®cal

location under the pial surface [4, 5, 6, 8, 9, 10, 16, 18,

19, 20, 21, 23, 24, 30, 31, 32, 33, 34, 35].

This article is the analysis of a consecutive series of

12 patients aëcted by a brain stem CM and surgically

treated at the University Neurological Hospital of

Lyon, between 1992 and 1998, by the senior neuro-

surgeon (M.S.) Special emphasis has been put on the

study of the pre-and post-operative functional status of

the patients measured by the Karnofsky scale [12]

(Table 1).

Clinical Material and Methods

Patients' Presentation

The 12 patients were referred to our institution because of a sud-

den or rapidly progressing deterioration of their neurological status.

Nine patients were male and three female. Age ranged from 24 to

63 years, 43 on average. Eleven patients were referred for a hemor-

rhage. For ®ve of them, it was the ®rst bleeding; in the six others, it

was a rebleeding (the second one in 5 patients and the third in

one). Only one patient was referred for a progressing mass-eëct

syndrome.

All patients had MRI at the ®rst imaging investigation or after a

CT. All of them had in addition four vessels angiography by femoral

catheterization. Angiography was performed to provide the maxi-

mum vascular anatomy information including a detailed study of the

venous system, before surgical decision was made and the choice of

the surgical approach decided upon.

CM location was: lateral thalamo-mesencephalic in 1 case, lateral

mesencephalic in 2 (one involving the quadrigeminal plate and one

the tegmentum), in the pons in 5 (on the midline in 4 and laterally

in 1), at the ponto-medullary junction in 3 (2 on the midline and 1

laterally), in the medulla, laterally, in 1.

One patient (with a solitary brain stem CM) had a family history

of CMs, and two had multiple localizations. Two patients had an

associated clear developmental venous abnormality in the close

vicinity of the CM, and two others a simple but particularly marked

vein of drainage of the cavernoma. One patient with a midline pon-

tine CM had a Chiari II malformation (that was treated by cervico-

occipital posterior decompression at the same time as the resection of

the cavernoma).

All patients, with the exception of one, had headaches, more or

less intense. All had multiple neurological symptoms and signs (cra-

nial nerve de®cits, motor weakness, sensory disturbances, cerebellar

discoordination. . . .) depending upon the rostro-caudal level of the

CM and its location within the brain stem. Two patients soon after

admission to the hospital were in coma with severe vegetative dis-

turbances and respiratory distress, necessitating an emergency tra-

cheal intubation with assisted ventilation. The detailed clinical pic-

ture for each patient will not be described in the article; only the

predominant clinical manifestation(s) will be mentioned. Table 2

summarizes the preoperative data of the patients in this series.

Only two patients were operated on within the ®rst three days after

the (last) bleed. The others had surgery in the subacute phase, which

ranged from ten days to 10 months (seven weeks on average), after

the clinical status had improved and was stabilized.

The severity of the patients' functional status at the time of oper-

ation was quanti®ed by evaluating the degree of dependance/activity

with the Karnofsky scale (KS) (see corresponding table). Two pa-

tients were operated on in comatose state (KSU 20), ®ve in a state of

functional dependance (KSU 60) and ®ve with severe neurological

de®cits but still with independant functional status (KSV 60) (Table

2).

Surgical Treatment

All patients of this series were referred by their neurologist for

surgical resection of the CM after consent had been obtained from

both the patient and relatives.

The Choice of the Surgical Approach was essentially based on the

location of the CM, i.e., its topography according to rostro-caudal

level, its ventro-dorsal situation within the brain stem, its more or

less super®ciality under the brain stem surface. The pre-existing

neurological disorders, as well as the foreseeable new de®cits inher-

ent to the intented incision of the overlying parenchyma, were of

course taken into account for designing the surgical approach (Table

3).

The surgical approach was:

± Supraoccipital transtentorial, on the side of the lesion, in two pa-

tients: once for a thalamo-mesencephalic CM located in the pul-

vinar, the subthalamic area and the upper part of the tegmentum;

once for a CM involving the quadrigeminal plate, (Fig. 1).

± Suboccipital infratentorial-supracerebellar, on the side of the

cavernoma, once; it was for a CM located within the mesen-

cephalon and bulging under the dorso-lateral surface of the cere-

bral peduncle.

± Retrosigmoid and through the cerebello-pontine angle, in three

cases of CM located ventro-laterally in the pons and/or the

medulla, (Fig. 2).

± Through a median low suboccipital (and intertonsillar) approach.

This approach passed through the Foramen of Magendie, that

was enlarged by displacing laterally each tonsil after having freed

and opened both cerebello-medullary ®ssures up to the Luschka

lateral foramen of the IVth ventricle. This approach was used

to remove ®ve CMs located at, or in the vicinity of, the midline

under the ¯oor of the IVth ventricle at the pontine or the ponto-

medullary levels. Same approach was used, but had to be com-

pleted by a splitting of the lower part of the vermis in the case in

whom a Chiari malformation was associated with the pontine CM

(Fig. 3).

Surgical Steps. All patients were operated on under general anes-

thesia in the sitting position. Microsurgical techniques were used in

Table 1. Karnofsky Rating Scale

Score Findings

100 normal, no complaint

90 normal activity, minor symptoms

80 normal activity with eört. Some symptoms

70 care for self. Unable to carry on normal activity

60 requires occasional assistance

50 requires considerable assistance and care

40 disabled, requires special care and assistance

30 severely disabled, hospitalized

20 very sick, requires supportive measures

10 Moribund

844 M. Sindou et al.

all patients as soon as the craniotomy was completed. In all patients

the exposed brain stem surface had a xanthochromic coloration at

the site of the CM. In the majority of cases there was an additional

dark-blue coloured small area, which corresponded to the bulging

hematoma surrounding the cavernoma. When present, incision of

the brain stem surface was performed at this very point.

The incision was as small as possible (less than 10 mm in most

cases) to avoid increasing the neurological de®cits. After having

sucked out the clots of the hematoma, and also the blood coming

from inside the malformation as well as the serous liquid from even-

tual microcystic cavities, the cavernoma was collapsed and detached

from the gliotic surrounding tissue. Then the mass was disconnected

by using bipolar coagulation and microscissors from the tiny feeding

and draining vessels. When big, the draining veins were respected

at all costs, the cavernous mass being disconnected from the

vein(s), passing as close as possible to the cavernoma. In the two pa-

tients with an associated developmental venous abnormality, the

venous malformation was not touched after the CM was removed

(Fig. 4). After the CM has been resected and removed, the cavity

was washed with saline, and its walls covered with small pieces of

Surgicel.

After surgery, the patients were admitted to the Intensive Care

Unit for the early post-operative period.

Results (Table 3)

Cure of the Lesion

In the 11 patients in whom CM was revealed by

bleeding, the hematoma was totally evacuated and

the cavernous mass could be entirely removed. Com-

pleteness of the removal was checked again by post-

operative MRI performed before discharge from the

hospital, and checked one year later. This new check-

up at one year was important to be certain of the

total eradication of the lesion especially if at the early

control there was some contamination of the cavity by

residual blood or ``hematic'' surgicel deposits on its

walls.

In the case with the giant multilobulated pontine

CM, which did not bleed, but was operated on because

of threatening pseudo-tumorous evolution, the resec-

tion was only partial. For, it was very di½cult in this

case to ®nd clearcut boundaries between the cavernous

masses and the surrounding parenchyma.

Post-Operative Events

All patients were hospitalized in the Intensive Care

Unit immediately after surgery, whatever their preop-

erative status might be. The two patients operated on

in comatose state recovered consciousness within a few

days after surgery. Assisted ventilation was withdrawn

after three weeks in both patients, one of them after

completion of a tracheostomy that could be removed

some weeks later.

The 10 patients operated on in conditions of a good

level of consciousness awoke normally (i.e., with a

Glasgow Score superior or equal to 14/15) and were

extubated at the 24th hour. But six of them because of

secondary respiratory disturbances necessited tracheal

Table 2. Patient Series (pre-op. Data)

Case

n�Sex

age (y)

Location Bleeding (s) Dominant revealing

symptom/sign

Recent

bleeding

on MRI

Delay

between

last warning

symptoms

and surgery

Pre-op.

functional

status

(Karnofsky

scale)

1 M34 mesenceph. quad. plate (lateral) three ataxia � 2 w 90

2 M63 thal.-mesenceph (lateral) two ataxia � 2 m 70

3 F57 pons (¯oor IVth V) (median) two diplopia � 10 m 90

4 M59 pons (lateral) one hemiparesia � 10 d. 60

5 F24 pons (¯oor IVth V)

multilobulated mass

/ tetraparesia ÿ / 60

6 M43 pons (¯oor IVth V) (median) one comatose state � 3d 20

7 M63 pons (¯oor IVth V) (median) one headaches, ataxia � 15d 100

8 F46 ponto-medullary (lateral) two dysphagia, dysphonia,

hemiparesia

� 2d 40

9 M38 ponto-medullary (¯oor IVth V)

(median)

one comatose state � 15d 20

10 M35 medullary (lateral) one headaches, dysphagia,

dysphonia

� 26d 60

11 M56 mesenceph. (lateral) two ataxia, diplopia � 15d 50

12 M33 ponto-medullary (¯oot IV th V)

(paramedian)

two diplopia ataxia � 25d 60

Functional Results in Brain Stem Cavernomas 845

reintubation ± some with assisted ventilation ± be-

tween the third and the ®fth day after surgery. For

these six patients duration of their stay in ICU ranged

from 10 to 15 days according to cases (Table 4).

Of the 8 overall patients who needed respiratory

assistance (i.e., the two operated on in comatose state

and the six who needed secondary arti®cial ventilation

because of respiratory aggravation) four had to be

tracheostomized (transiently in three, for two weeks on

average), so as to facilitate suppression of ventilatory

assistance.

No other major complication(s) occured in our

series with the exception in one patient of kidney fail-

ure which necessitated transient dialysis.

Long-Term Outcome

Follow-up in the series ranged from 1 to 7 years

(5.5 years on average). There was no mortality in this

series, neither in the early post-operative period nor in

the follow-up period.

Table 3. Patient Series (Post-op. Data)

Case

n�Location Pre-op

functional

status

(Karnofsky

scale)

Surgical

approach

Removal

T (total)

P (partial)

Main post-op

event(s)

Duration

ICU

(days)

Post-op

functional

status at

discharge

(Karnofsky

scale)

Functional

status

at one year

(Karnofsky

scale)

Overall

result

1 mesenceph. quad.

plate (lateral)

90 supra-occipital

transtentorial

(lateral)

T respiratory

disturbances

40 60 60 ��&

2 thal.-mesenceph

(lateral)

70 supra-occipital

transtentorial

(lateral)

T frontal

hydroma

(transient)

15 70 90 �%

3 pons (¯oor IVth V)

(median)

90 subtonsillar, ¯oor

of IVth V

T respiratory

disturbances

16 70 90 ÿ!

4 pons (lateral) 60 retro-sigmoid,

cerebello-

pontine

T respiratory

disturbances

15 60 90 ��%


multilobulated

mass


of IVth V

P CSF ®stula

(transient

after lumbar

drainage)

9 40 50 �&


(median)


of IVth V

T hydrocephalus

(permanent,

CSF shunt)

13 40 60 ��%


(median)


of IVth V

T none 3 90 100 ÿ!

8 ponto-medullary

(lateral)

40 retrosigmoid,

cerebello-

pontine

T respiratory

disturbances

13 70 80 ��%

9 ponto-medullary

(¯oor IVth V)

(median)


of IVth V

T respiratory

disturbances

9 50 90 ��%

10 medullary (lateral) 60 retrosigmoid,

cerebello-

pontine

T respiratory

disturbances

11 60 70 �%

11 mesenceph. (lateral) 50 sub-occipital

infratentorial,

supra-

cerebellar

(lateral)

T respiratory

disturbances

7 60 80 ��%

12 ponto-medullary

(¯oor IVth V)

(paramedian)


of IVth V

T none 5 90 90 ��%


At one year after surgery, the functional neurologi-

cal status was evaluated using the Karnofsky scale. 9

patients had a score superior to 60 ± which means that

they were independant for daily life ± three of them

being above 80 (i.e., that they could resume a normal

activity in spite of some symptoms and slight de®cits).

3 had a score inferior to 60: one (at 50) was requiring

occasional help (for walking) and two (at 40) required

considerable assistance and care.

Comparison of the functional status, at one year

after surgery, with the one before surgery, shows

that: 8 patients had signi®cantly improved, 2 were

stabilized, and 2 were worse: one slighlty and one sev-

erely, the latter needing a permanent tracheostomy

and a wheelchair.

For the patients with a follow-up longer than one

year, there was no secondary deterioration except in

one who required a CSF shunt for a normal pressure

hydrocephalus syndrome and did well after the shunt

procedure.

Fig. 1. Mesencephalic CM located in the right part of the quadrigeminal plate (left Fig., MRI-T2, preoper.), totally removed through a right

supra-occipital transtentorial approach (right Fig., MRI-T1, post-oper.)

Fig. 2. Pontine CM located in the right part of the upper pons with a huge hematoma (left Fig., MRI-T1, pre-oper.), totally removed

through a right cerebello-pontine angle approach with incision of the pons below pars major of the trigeminal nerve (right Fig., MRI-T2, post-

oper.)


Discussion

Results of Surgery

The present series was characterized by the existence

of preoperatively severe clinical disturbances in all the

patients. The mean Karnofsky score of the series was

60% at the time of surgery despite most of the patients

being operated on after an average delay of seven

weeks during which the clinical status had improved

until stabilization. With the exception of one patient

who presented with a progressive mass-eëct syn-

drome, all patients had one (or several) bleed(s) from

their malformation. Because, in all these patients,

evolution was threatening, we decided together with

the refering neurologist, to convince the patient and his

family ± that surgical resection was the best therapeu-

tic option. This policy seemed to us logical especially

when considering that CMs treated conservatively

generally lead to severe disability and entail a mor-

tality rate of the order of 20% [35]. The radiosurgical

option, in spite of some articles claiming that radio-

surgery might be eëctive in CMs [13, 28], did not

prove to be e½cacious or even innocuous [2, 11, 26,

29].

There was no mortality in this series. A majority of

the patients improved after surgery; only one was sig-

ni®cantly worse. The mean Karnofsky activity score

increased from 60 (before) to 70 (after) surgery.

These good surgical results (i.e., 91% of the patients

cured without signi®cant deterioration) are concor-

dant with the ®gures reported in the literature (Table

5): from 83% to 89% according to the series (Berta-

lanÿ et al. 13 pts surgically treated [4], Fahlbusch and

Strauss. 10 pts [8] Zimmerman et al. 16 pts [34], Frit-

schi et al. 93 pts [9], Sathi et al. 23 pts [25], Amin-

Hanjani et al., 14 pts [3], Porter et al. 86 pts [21], Ziyal

et al. 9 pts [35].

Surgical Indications and Anatomical Considerations

Indications constitute a di½cult problem to deal

with. Most authors agree that among brain stem CMs

those which are asymptomatic, or pauci-asympto-

matic if quiescent, have not to be touched surgically,

especially if they are small and enclosed with a large

rim of parenchyma around them. On the contrary for

symptomatic brain stem CMs, as soon as they manifest

a tendency to rebleed, literature date as well as the

results from our own series, plead for a decision for

surgical resection before mass-eëct and/or further

bleed(s) cause severe de®cits. As a matter of fact in

these «symptomatic» forms of CMs, spontaneous

evolution generally leads to irreducible disability.

As optimal timing for surgery, most surgeons prefer

the subacute phase, after the patient's clinical status

has stabilized and the hematoma has become partially

organized.

If the CM corresponds to the so-called «exophytic»

type -i.e., has a super®cial subpial extension ± there is

no problem of localizing the lesion and for removing it

without signi®cant risk. On the contrary if the CM is

deeply situated inside the brain stem parenchyma, the

risk to produce neurological worsening has to be seri-

Fig. 3. Pontine CM located in the middle part of the lower pons in a patient with a Chiari malformation (left Fig., MRI-T1, pre-oper.), totally

removed through a (transvermian) approach of the ¯oor of the IVth ventricle


ously evaluated before a decision is taken. A careful

neurological examination and a precise MRI study

with a rigorous elucidation of the brain stem surgical

anatomy are important prerequiritives. As a matter of

fact, in patients in whom the cavernoma is covered by

a signi®cant rim of neural tissue, the new de®cits that

the incision will logically create to have access to the

lesion have to be taken into account and objectively

discussed with the patient and his family.

Although brain stem structures may be distorted

because of the CM pathology, it may be of interest

to have in mind some important elements of surgi-

cal anatomy when considering surgical approaches.

Motor tracts are located in the ventral portion of the

brain stem. Traversing through the ventral aspect and/

or damaging the perforating vessels would result in

pyramidal de®cits. The tegmentum with the reticular

formation and the medial longitudinal fasciculus

Fig. 4. Cavernous angioma associated with a developmental venous abnormality. Upper left: paramedian ponto-medullary cavernous mal-

formation under the ¯oor of the IVth ventricle. Upper right: axial views showing the cavernoma and the developmental venous anomaly. Lower

left: sagittal view, and lower right: axial view, after operation, showing complete removal of the cavernoma and preservation of the venous

abnormality


occupy the mid and dorsal portions of the brain stem.

The cranial nerve and vestibular nuclei and the extra-

lemniscal sensory tracts are located in the dorsal and

lateral parts. For lesion which are situated under the

¯oor of the IVth ventricle, the nuclei of the abducens

and facial nerves (facial colliculus) in the paramedian

region and the medial longitudinal fasciculus on the

midline, are structures at risk. Detection of the facial

nuclei by electrical stimulation of the ¯oor of the IVth

ventricle can be a useful tool for identifying their loca-

tion. Two «safe entry zones» have been described: one

above and one below the facial colliculus over 10 mil-

limeters in length heigth each [15]. For lesion situated

ventrolaterally within the brain stem, approach via an

antero-lateral brain stem surface incision is generally

well-tolerated, especially at the level of the pons [21]

but also of the medulla [6].

Conclusions

± Since modern MR imaging, brain stem Cavernous

Malformations (CMs) can be easily detected and

their anatomical situation and relationships pre-

cisely de®ned.

± Thanks to microsurgical techniques, most CMs can

be cured with satisfactory results, i.e., with a com-

plete resection of the lesion and without signi®cant

neurological deterioration, provided they are «sur-

gically accessible» and reached through an «appro-

priate minimally invasive approach».

± «Symptomatic» CMs manifesting with bleeding(s),

or a progressing mass-e¨ect syndrome, are better

operated on. As a matter of fact, according to

literature data or experience from our institution,

spontaneous evolution generally leads to severe

and irreversible disability. Radiosurgery has not

been proven to be e¨ective and/or innocuous in the

long-term.

± Optimal timing is after the patient's status has

stabilized.

± Exophytic CMs are generally easy to remove with-

out creating additional de®cits. Enclosed CMs would

have to be operated on only if passing through the

overlying parenchymal rim would not create new

severe de®cits, unless the cavernoma demonstrates a

dangerous tendency to bleed.

± The surgical incision has to be at the very point

where the CM and/or the satellite hematoma is (are)

the most super®cial under the brain stem surface.

The surgical approach has to be designed to reach

this entry point.

± Hospitalization in the Intensive Care Unit for the

®rst post-operative week is a prudent measure as

even patients who awake normally from anesthesia

can secondarily worsen (hopefully, transiently) their

respiratory conditions.

± Asymptomatic CMs or those with minor manifes-

tations should be managed conservatively, espe-

cially if they are small and deeply situated and en-

closed with in a wide rim of neural tissue. They

should be monitored over a limited period and fre-

quent re-examinations.

Table 4. Pre- and Post-Operative Respiratory Status in the Patients' Series

Scale of respiratory status Pre-oper D1

Post-oper

D4

Post-oper

On discharge

from the hospital

to home

Grade De®nition

R0 normal respiratory state 9 7 2 11

R1 slight respiratory disturbances (without

the necessity for tracheal intubation)

1 3 2 1 (RT)

R2 respiratory disturbances necessitating

tracheal intubation, but without the

need of assisted ventilation

3


tracheal intubation, with the need of

partially controlled ventilation

1


tracheal intubation, with the need

for full-time controlled ventilation

2 (comatous

patients)

2 4

* RT Tracheostomy (permanent)


References

1. Aiba T, Tanaka R, Koike T, Kameyama S, Takeda N, Komata

T (1995) Natural history of intracranial cavernous malforma-

tions. J Neurosurg 83: 56±59

2. Amin-Hanjani S, Ogilvy CS, Candia GJ, Lyons S, Chapman PH

(1998) Stereotactic radiosurgery for cavernous malformations:

Kjellberg's experience with proton beam therapy in 98 cases at

the Harvard Cyclotron. Neurosurgery 42: 1229±1238

3. Amin-Hanjani S, Ogilvy CS, Ojemann RG, Crowell R (1998)

Table 5. Literature Series

Series of b.s CMs

treated surgically

Total nb (nb

presenting with

hemorrhage)

Nb of totally

resected

Outcome Surgical removal recommended

Symon et al.

1991

7

(7)

7 ± mortality: none

± improved: 7

with an appropriate incision being made into that part

of the brain stem most directly overlying the lesion.

Bertalan¨y et al.

1991

13 13 ± mortality: none

± improved: 8

± unchanged: 1

± aggravated: 4

In symptomatic CMs having bled, in the subacute

phase when the hematoma is partially organized

and the patient's condition has stabilized.

Fahlbusch and

Strauss 1991

10

(10)


± improved: 6

± unchanged: 3

± aggravated 1

in patients with recurrent hemorrhage, persistent or

progressive neurological de®cit, during the subacute

stage. Late surgery increases the risk of additional

neurological de®cit.

Zimmerman et al.

(1991)

16

(10)

13 ± mortality: 1

± improved or

unchanged: 14

± aggravated: 1

when the lesion is located super®cially and an

operative approach can spare eloquent tissue.

Fritschi et al.

1994

93

(75)


± improved: 78

± aggravated

(moderately 14,

severely): 1

for symptomatic lesions with either a sudden onset

attributable to a hemorrhage or a slowly progressive

neurological de®cit. Deep lesions that lack a

super®cal extension are unlikely to have a good

surgical outcome because eloquent structures will be

injured.

Pechstein et al.

1997

7 ± mortality: 1

± improved: 2

± unchanged: 3

± aggravated: 1

in symptomatic patients in whom CM seems to reach

the surface of the brain stem.

Bouillot et al.

1996

17

(16)

14 ± mortality: 2

± improved: 10

1 unchanged: 2

± aggravated: 3

when CMs are presenting with hemorrhage(s) and

considered anatomically accessible.

Lewis et al.

1995

24 22 ± mortality: none

± improved or

± unchanged: 21

± aggravated: 3

in symptomatic lesions, the risk of permanent

morbidity being less than the natural history.

Amin-Hanjani

et al. 1998

14

(12)


± improved: 5

± unchanged: 7

± aggravated: 2

when the patient is su½ciently neurologically

compromised to reap the potential bene®ts of

surgical treatment.

Sakai et al.

1997

9

(8)


± improved or

± unchanged: 8

for CMs which are located near the brain stem surface.

Porter et al.

1999

86

(83)

94%

67 out of 71 MRI

checked

± mortality: 3

± improved: 3

± unchanged: 7

± aggravated: 8

in patients with symptomatic hemorrhage who harbor

lesions that approach the pial surface.

Cantore et al.

1999

11 10 ± mortality: 1

± improved: 4

unchanged: 6

± aggravated: 1

In addition to the parenchymal windows produced by

the CMs, safe entry zones are � ¯oor of the IVth

ventricle and the anterior surface of the medulla and

pons

Ziyal et al.

1999

7

(7)


± improved: 7

in CMs which are symptomatic, have bled or are

growing, and are approachable through one of the

pial surfaces of the brain stem. Radiosurgery is not

recommended in such cases.


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Comments

In this excellent article, Prof. Sindou and colleagues present a de-

tailed retrospective analysis of a 12-patient series operated on for

brain stem cavernoma, and a concise yet well-represented review of

the literature. Their reported ®ndings are similar to previous litera-

ture published on this lesion, functional results are reasonably good

and conclusions are appropriate. I would like to address the authors'

suggested selection criteria for surgery. I agree in full that ``symp-

tomatic'' cavernous malformations manifesting with bleeding or a

progressive mass-eëct syndrome should undergo surgical treat-

ment; however, based on the present skill level of brain stem surgery

as well as my experience with this particular lesion, I am inclined to

believe that `àsymptomatic'' patients should also be considered for

surgery. Young adult patients leading an active life who undergo

MRI for some reason and are discovered to be harboring a cavern-

ous malformation in a critical area such as the brain stem do not

merit a `watch and wait' passive policy as such a ®nding will condi-

tion their life negatively. Now that we have the understanding and

technical capability to remove a brain stem cavernoma with very

low morbidity, I strongly suggest that surgery be oëred or at least

considered also in a selected subgroup of so-called `àsymptomatic''

patients.

A. Bricolo

The authors report on a retrospective study of their personal ex-

perience with surgical resection of brain stem cavernous malforma-

tions (CM) in 12 consecutive patients. The surgical results are excel-

lent. In 11 patients the CM was totally resected. The majority of the

patients had improved at one year after surgery. The authors con-

clude that brain stem Cms have a high bleeding and re-bleeding risk.

Considering the grave natural history, the authors argue that these

lesions should be surgically resected, particularly once they have bled.

The authors present no new aspects concerning the natural history

and management of these lesions. Their results and conclusions are

in accordance with the current literature and cited larger series.

Nevertheless, publication of this plead for radical resection is rec-


ommended in view of the still existing reluctance to operate in this

area and ignorance of the often devastating sequelae when these

lesions are left untreated.

H. Reulen

Correspondence: Professor Marc Sindou M.D., D.Sc., Neuro-

chirurgie A, Department of Neurosurgery, Hopital Neurologique P.

Wertheimer and University of Lyon, 59 Bd Pinel, 69003 Lyon,

France.


!!!pontine cavernoma

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