OPERATIVE TECHNIQUES
Olivier Delalande, M.D.
Fondation Ophtalmologique
A. de Rothschild,
Pediatric Neurosurgery Unit,
Paris, France
Christine Bulteau, M.D.
Fondation Ophtalmologique
A. de Rothchild
Pediatric Neurosurgery Unit,
Paris, France
Georges Dellatolas, M.D., Ph.D.
INSERM U 472,
Biostatistic and Epidemiology Unit,
Hôpital P. Brousse,
Villejuif, France
Martine Fohlen, M.D.
Fondation Ophtalmologique
A. de Rothschild,
Pediatric Neurosurgery Unit,
Paris, France
Claude Jalin, M.D.
Fondation Ophtalmologique
A. de Rothschild,
Pediatric Neurosurgery Unit,
Paris, France
Virginie Buret, Psy.
Fondation Ophtalmologique
A. de Rothschild,
Pediatric Neurosurgery Unit,
Paris, France
Delphine Viguier, M.D.
INSERM U 472,
Biostatistic and Epidemiology Unit,
Hôpital P. Brousse,
Villejuif, France
Georg Dorfmüller, M.D.
Fondation Ophtalmologique
A. de Rothschild,
Pediatric Neurosurgery Unit,
Paris, France
Isabelle Jambaqué, Psy., Ph.D.
Université Paris Descartes,
Laboratoire Cognition
et Comportement,
Cedex, France
Reprint requests:
Olivier Delalande, M.D.,
Fondation Ophtalmologique
A. de Rothschild,
Service de Neurochirurgie Pédiatrique,
25–29 rue Manin,
75940 Paris Cedex 19-France.
Email: odelalande@fo-rothschild.fr
Received, March 24, 2006.
Accepted, September 8, 2006.
NEUROSURGERY
VERTICAL PARASAGITTAL HEMISPHEROTOMY:
SURGICAL PROCEDURES AND CLINICAL LONG-TERM
OUTCOMES IN A POPULATION OF 83 CHILDREN
OBJECTIVE: Hemispherotomy techniques have been developed to reduce complication
rates and achieve the best possible seizure control. We present the results of our pediatric patients who underwent vertical parasagittal hemispherotomy and evaluate the
safety and global long-term outcome of this technique.
METHODS: Eighty-three patients underwent vertical parasagittal hemispherotomy by
the same neurosurgeon (OD) between 1990 and 2000. We reviewed all patients between
2001 and 2003 for a standard global evaluation. The general principle is to achieve,
through a posterior frontal cortical window, the same line of disconnection as performed with the classic hemispherectomy, while leaving the majority of the hemisphere
intact along with its afferent and efferent vascular supply.
RESULTS: Seventy-four percent of the patients were seizure-free; among them, 77%
were seizure-free without further drug treatment. Twelve percent rarely had seizures
(Engel Class II) and 14% continued to have seizures (Engel Class III or IV). The results
varied according to the etiology, but this variation was not statistically significant. The
early postoperative course was uneventful for 94% of the children, and shunt placement was necessary in 15%. We found a correlation between the preoperative delay and
the Vineland Adaptive Behavior score: children with a longer duration of seizures had
lower performances.
CONCLUSION: Vertical parasagittal hemispherotomy is an effective surgical technique
for hemispheric disconnection. It allows complete disconnection of the hemisphere
through a cortical window with good results in terms of seizure outcome and a comparably low complication rate.
KEY WORDS: Children, Epilepsy surgery, Hemispherectomy, Hemispherotomy, Long-term outcome
Neurosurgery 60[ONS Suppl 1]:ONS-19–ONS-32, 2007
A
mong the patients who experienced
pharmacologically refractory seizures
associated with a clinical hemispheric
syndrome owing to a diffuse pathology of one
cerebral hemisphere (21), functional hemispherectomy presents an effective surgical procedure and has the highest rate of seizure control (9, 31). Approximately 77 to 80% of the
patients who underwent an operation were
seizure-free in the first reported series. Such a
surgical procedure has been largely proposed
in children with catastrophic epilepsy associated with a congenital or acquired hemispheric
cerebral pathology. The classical procedure of
anatomic hemispherectomy (5, 15, 17) was progressively abandoned by neurosurgeons to
DOI: 10.1227/01.NEU.0000249246.48299.12
avoid long-term complications or, in some
cases, fatal outcomes, mainly owing to cerebral
hemosiderosis that resulted from dead space
produced by removal of the entire hemisphere
(10, 16, 19, 22), as well as immediate postoperative risks such as considerable intraoperative
blood loss (3, 20). Adams (1) proposed to turn
subdural dead space into epidural dead space.
In 1983, functional hemispherectomy was introduced by Rasmussen (22) based on a combination of partial anatomic excision and disconnection of the remaining lobes. Furthermore,
hemidecortication was proposed by removing
only the gray matter, sparing as much as possible of the white matter and avoiding opening
of the ventricle (2, 12, 32, 33). However, the effi-
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DELALANDE ET AL.
ciency of this technique on seizure control was diminished,
especially in the group of children with diffuse cortical dysplasia (4). To further decrease complication rates, new surgical procedures have been developed that reduce the volume of brain
removal and increase the ratio of disconnection to resection.
These surgical techniques require a smaller skin incision and
bone flap, which offers the advantages of reducing blood loss
and avoiding the exposure of large venous sinuses. This concept
replaces the term “hemispherectomy” with “hemispherotomy,”
as proposed by Olivier Delalande in 1992 (7).
Various modifications of the hemispherotomy have been
described (3, 7, 8, 24, 25, 27, 28). The peri-insular hemispherotomy proposed by Villemure and Mascott (28) and the so-called
“modified lateral hemispherotomy” (3) are the largest reported
series to date. However, they are more difficult to perform in
children born with cerebral malformation (hemimegalencephaly or cortical dysplasia) because of abnormal brain
parenchyma and ventricular anatomy. Moreover, in these
series, different hemispherectomy techniques were applied
with a relatively short-term follow-up period and small number of patients. Holthausen et al. (11) reported on the largest
retrospective multicenter study to date. In that study, there was
a complete disappearance of seizures in approximately 50 to
70% of the patients. The surgical technique with the best results
was the “hemispherotomy technique.” But, long-term postoperative outcome (⬎5 yr) seems to be less effective, with a
decrease of seizure-free patients from 76% at 1 year postoperatively to 58% at the time of the 5-year follow-up examination
(14). Moreover, it is accepted that postoperative seizure outcome is influenced by the underlying pathology, with the worst
outcome in the group of “hemispheric cortical dysplasia” compared with patients with Sturge-Weber syndrome, Rasmussen
encephalitis, or vascular insults.
We present the vertical approach of hemispherotomy that
we have used for the past 15 years, which differs from the previous techniques in two main aspects: 1) the major principle is
to further reduce the extent of brain resection by increasing the
amount of disconnection, thereby introducing the concept of
hemispherotomy and 2) the use of the vertical approach rather
than the lateral approach offers the possibility of doing exactly
the incisions performed in anatomic hemispherectomy, based
on reliable landmarks. This allows the surgeon ensure that an
effective total disconnection of the hemisphere is achieved. The
technique that we propose to call “vertical parasagittal hemispherotomy” (VPH) is described in this article because it differs
from the previous surgical techniques of functional hemispherectomy. The aim of this retrospective study is to report on
our results of a large population of children operated by the
same surgical technique (VPH) and by the same neurosurgeon
(OD) to appreciate the safety of this technique and evaluate the
global long-term outcome.
PATIENTS AND METHODS
The patient is operated on in the supine position with the
head in a neutral position, but slightly elevated in the horizon-
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tal plane. A small parasagittal frontoparietal craniotomy
(approximately 3 ⫻ 5 cm, 1 to 2 cm from the midline, one-third
anterior and two-thirds posterior to the coronal suture) is performed with the posterior frontal and central region exposed
(Fig. 1A).
A limited cortical resection of approximately 3 ⫻ 2 cm is performed, reaching the ependyma of the ventricular roof (Figs.
1B, 1C, 2, and 3). The ventricle is opened, thereby delineating
the midline region as well as the posterior aspect of the thalamus, and anteriorly the foramen of Monro.
Following the roof of the lateral ventricle mesially, the corpus
callosum is identified. By using the ultrasonic aspirator with a
low level of vibration (10–20%), the callosal resection is first
performed posteriorly towards the splenium (Figs. 1B, 1C, 2,
and 3). The midline is always easy to find at this level because
the falx cerebri is close to the upper part of the splenium. The
resection of the splenium has to be pursued until the roof of the
third ventricle and the arachnoid of the cisterna ambiens are
exposed. Then, the posterior column of the fornix is cut at the
level of the ventricular trigone, from the arachnoid of the cistern ambiens reaching laterally to the choroidal fissure, behind
the pulvinar (Figs. 1F, 1G, and 2). The next step consists of performing an incision lateral to the thalamus. Posteriorly, there is
no connection at the level of the ventricular trigone. Laterally,
one can see the posterior part of the choroid plexus of the temporal horn (Figs. 1F, 1G, and 2), which serves as a guide for the
incision lateral to the thalamus. This incision is performed
strictly vertically and extends from the trigone to the most anterior part of the temporal horn (Figs. 1I, 1J, 2, 3, 4, and 5), by
unroofing the temporal horn entirely, anterior to the coronal
plane of the foramen of Monro (cpfM). The incision has to
remain within the white matter as laterally as possible to avoid
any damage to the lateral aspect of the thalamus.
As a next step, the completion of the callosotomy is achieved
anteriorly, thereby resecting the genu until just above the anterior commissure (Figs. 1O, 1P, and 2). Just as for the posterior
part of the corpus callosum, the section is performed intracallosally to the interhemispheric cistern. The pericallosal arteries
(pca) are most often seen through the pia mater. The resection
of the genu through the ventricular roof most often requires
lifting the patient up to have good visibility anteriorly.
It is then necessary to resect the most posterior part of the
gyrus rectus (Figs. 1R and 1S). This resection allows one to
visualize, across the arachnoid, the first segment of the anterior
cerebral artery (aca) and the optic nerve (on), and provides
space for a straight incision oriented anterolaterally through the
caudate nucleus towards the anterior part of the lateral incision
(Figs. 1T, 1U, 2, 3, and 4). This last dissection will cut all the connections from the anterior temporal lobe, the amygdala, and
the frontal lobe. The hemispherotomy is now complete, having
isolated the entire epileptic cortex from the subcortical structures (Fig. 2A). The whole disconnection is easily performed
with the ultrasonic aspirator and with minimal hemorrhage.
Perforating arterial branches from the anterior and middle cerebral artery can be easily spared by using a low level of vibration. On the outside, there may be venous bleeding, particu-
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VERTICAL PARASAGITTAL HEMISPHEROTOMY
larly in cases of hemimegalencephaly, but this bleeding is rarely
considerable and is usually easily controlled.
Two modifications have been implemented since this technique was initiated. The cortical window initially reached the
midline. This made the callosotomy easier, but it was then usually necessary to cut large veins close to the sagittal sinus. The
cortical window was displaced laterally as described above.
Using the lateral approach, it is always possible to spare large
veins; a smaller vein can be sacrificed, provided it only drains
the cortical region to be removed. The size of the window has
been considerably reduced in all cases except for hemimegalencephaly. In the latter cases, the thickness of the brain and
anatomic abnormalities make the procedure more difficult, and
a larger route is a condition to avoid any damage to the remaining brain. In hemimegalencephaly, the shape of the anterior
part of the corpus callosum is sometimes large and/or the
frontal horn of the lateral ventricle might be atretic (Fig. 2, B
and C). One has to keep in mind that the anatomic guidelines
are the upper part of the corpus callosum and the midline arteries. A careful analysis of the three-dimensional anatomy of the
affected hemisphere has to be done in cases of hemimegalencephaly and some rare cases of complex hemispheric dysplasia.
One must be aware that the brain midline cannot be in the cranial midline. In all of the cases we have encountered, the falx
cerebri posteriorly, the roof of the temporal horn laterally, and
the pericallosal arteries anteriorly are always remarkable landmarks that should be followed. In all other indications, hemispheric atrophy and lack of change of gross anatomy makes the
procedure easy, allowing a narrower route.
The hemispherotomy dissection has to be large enough to
be assessed by axial and coronal magnetic resonance imaging (MRI) scans. All the children in this series had MRI scans
at 3 months postoperatively to exclude complications such as
active hydrocephalus or subdural hygroma. The line of the
hemispheric disconnection was visible on the axial, sagittal,
and coronal planes in all cases (Fig. 2A).
We performed a retrospective study of all patients who
underwent hemispheric disconnection for hemispheric refractory epilepsy between April 1990 and September 2000. Eightythree patients underwent hemispherotomy by the same surgical
technique (VPH) and by the same neurosurgeon (OD).
Preoperative evaluation included clinical, neurophysiological
(video electroencephalographic [EEG] telemetry), and neuroradiological (MRI) investigations in all patients with or without
neuropsychological testing, single-photon emission computed
tomography, Wada testing, and functional MRI scans. All data
were discussed at our multidisciplinary staff conferences. Sixtyfive children were from France and 18 were from other countries. Postoperative follow-up examinations were performed
at 3 months and 1 year. They included a clinical evaluation,
assessment of seizure outcome, cerebral MRI scans, and EEG.
Thereafter, most of the children were seen for clinical evaluation, depending on the evolution, until the end of the
antiepileptic drug treatment. To analyze the long-term neurological, cognitive, and social outcome of this large population,
we have reviewed all French patients and have included an
NEUROSURGERY
external medical assessment of our foreign population in the
period from December 2000 to June 2003.
We reviewed the French patients during a 2-day hospitalization at our institution for a standard global evaluation,
including seizure outcome, postoperative course, neurological examination, behavioral outcome, and cognitive assessment.
Seizure outcome was assessed using the Engel classification
(9). Neurological examination included ability to walk and
speak, motor and sensibility function, height, weight, head circumference (HC), developmental milestones before and after
surgery, type of schooling, weekly rehabilitation schedule,
socioprofessional status of parents, and systematic questioning of the parents to evaluate the progress in terms of language,
motor, behavior, and any other problems that they had
observed since hemispherotomy. We also recorded preoperative data (age of onset of seizures, type of seizures, frequency
of seizure at the time of surgery, psychomotor development
and clinical status of the child, EEG, and MRI scans) from the
medical file of each patient. Behavioral outcome was evaluated using the Vineland Adaptive Behavior Scale (26). This
scale is well known to assess four behavioral domains (i.e.,
communication, socialization, daily living skills, motor skills)
in handicapped individuals from birth to adulthood and
requires only the information provided by the caretaker of the
patient, but not the direct involvement of the child. For all
non-French patients, we sent a medical file to the referring
epileptologist in each country to analyze the epilepsy and
antiepileptic drug treatment and neurological and global
social outcome. We present the results of the whole population
with respect to seizure outcome, surgery related events, global
neurological long-term outcome, and Vineland score assessment.
Statistical Analysis
Statistical analysis was performed using SAS software (SAS
Institute, Cary, NC). The analysis focused on factors associated
with the Vineland scores (composite and specific scores),
indicating functional outcome. The main associated factors
examined were etiological group, age at onset of the seizures,
preoperative delay, postoperative follow-up, and the side of
the hemispherotomy. The general linear model procedure
was used for relations between categorical and continuous
variables; the Spearman Rho was used for relations between
continuous variables.
RESULTS
Of the 83 patients (45 boys and 38 girls), 43 (52%) underwent
a left hemispherotomy and 40 a right hemispherotomy. The
mean age of onset of seizure was 2.1 years (standard deviation
[SD], 3.3 yr; range, 0.0–13.5 yr), the mean age at hemispherotomy was 8 years (SD, 7.3 yr; range, 0.2–36yr), and the mean
age at the time of evaluation was 12.4 years (SD, 7.7 yr; range,
1.4–37.5 yr). We calculated a preoperative delay of 5.9 years
(SD, 6.3 yr; range, 0.25–28.7 yr) as the delay between the age of
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DELALANDE ET AL.
A
B
I
P
Q
C
D
J
K
R
S
FIGURE 1. Sequences of the surgical steps for the VPH. A, a parasagittal
frontoparietal craniotomy (3 ⫻ 5 cm, 1–2 cm from the midline, one-third
anterior and two-thirds posterior to the coronal suture) is performed with
the posterior frontal and central region exposed. B–E, in the first step, a lim-
ited cortical resection of approximately 3 ⫻ 2 cm is performed (Arrow 1)
followed by a posterior callosotomy (Arrow 2). F–H, section of the floor of
the ventricular trigone (Arrow 3) in the second step. Arrow 4, posterior
part of the temporal horn. I–N, in the third step, a laterothalamic incision
onset of seizures and the hemispherotomy and a postoperative
follow-up period of 4.4 years (SD, 2.7 yr; range, 0.03–11.3 yr) as
the time duration between the hemispherotomy and the age of
the evaluation. The medical characteristics are summarized in
Table 1. We reviewed all of the French (n ⫽ 65) patients except
one (Patient 61) and received the most recent data for all nonFrench (n ⫽ 18) patients except for two (Patients 101 and 103).
For these three patients, we picked up data in the medical file
from the preceding follow-up visit.
The etiology was determined according to the underlying
pathology based on imaging and pathological examination.
Four groups were identified and consisted of the following:
30 children (36%) with a multilobar cortical dysplasia (MCD;
Group 1), 25 children (30%) with Rasmussen encephalitis (RE;
Group 2), 10 children (12%) with Sturge-Weber syndrome (SW;
Group 3), and 18 children (22%) with ischemic-vascular sequellae (Seq; Group 4). In Group 1, 10 patients presented a large
cortical dysplasia, 19 had a hemimegalencephaly, and one had
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VERTICAL PARASAGITTAL HEMISPHEROTOMY
E
F
G
H
L
M
N
O
T
U
V
W
(Arrow 5) following the roof of the temporal horn of the ventricle is made.
O–Q, the fourth step is an anterior callosotomy (Arrow 6). R–S, the fifth
step is the resection of the posterior part of the gyrus rectus (Arrow 7).
T–X, the sixth step involves the dissection between the resected part of the
gyrus rectus and the anterior part
of the laterothalamic incision
(Arrow 8).
X
a “hemimicroencephaly.” In Group 4, 11 children had ischemic
lesions owing to vascular insult, three had a hemiplegia hemiconvulsion epilepsy syndrome, and three had ischemic sequellae after meningitis. Onset of seizures, the age at hemispherotomy, and the age at evaluation varied significantly according
to the etiology (P ⬍ 0.0001) and was earlier in the MCD group
and later in the RE group. Preoperative delay tended to be
lower in the MCD group than in the other three groups
(P ⫽ 0.04). The duration of the postoperative follow-up period
was not statistically different
between the groups (Table 2).
Before hemispherotomy,
all of the patients experienced generalized seizures,
partial seizures, and/or status epilepticus, but only the
MCD group exhibited infantile spasms (57%). The
NEUROSURGERY
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DELALANDE ET AL.
TABLE 1. Results of the 83 patients in this studya
Age at
Patient onset
no.
(yr)/sex
Age at
hemispherotomy (yr) Side
Postoperative course
Age at
evaluation (yr)
Multilobar cortical dysplasia Group 1 (n ⫽ 30)
1
0.1/M
1.0
L
No complication
8
0.03/F
0.3
L
No complication
9
0.16/M
3.9
L
No complication
11
0.0/M
0.6
R
VPS
12
14
17
0.0/F
0.0/F
4.2/M
22
25
29
32
33
37
4.5
1.5
5.9
7.2
2.6
1.7
7.5
L
L
L
No complication
No complication
VPS
11.2
5.0
8.5
0.0/M
0.2/M
0.01/M
0.15/F
0.0/F
0.04/M
0.6
7.9
0.3
6.8
1,0
3.6
L
R
R
R
L
R
No complication
No complication
VPS
Scar infection + VPS
SDPS
No complication
4.0
9.8
5.0
11.3
7.8
5.4
40
43
46
0.08/M
0.0/F
0.0/F
0.4
0.7
0.8
L
R
L
No complication
VPS
VPS
2.4
3.6
7.3
52
0.08/M
1.2
R
SDPS, Ventricul, VPS
3.3
53
55
0.04/M
0.0/F
18.2
0.4
R
L
No complication
SDPS
23.8
11.7
56
0.05/M
6.7
L
No complication
12.8
60
62
0.5/F
0.0/M
2.0
1.1
R
L
No complication
No complication
3.5
12.2
70
73
77
0.5/M
0.01/F
0.3/F
3.1
0.4
6.0
R
L
L
11.8
4.8
9.2
78
0.0/M
11.9
R
79
0.4/F
2.0
L
80
101
114
0.2/F
0.0/F
0.0/M
14.9
2.8
1.0
R
R
R
No complication
No complication
Severe hydrocephalus at 8 d
PO: external derivation, VPS
(3 wk PO).
Still invalid
Insipidis diabetus with metabolic acidosis. Deceased at 3 d PO
Reoperated at 18 mo after H. Deceased
2 mo later (infectious disease)
Latex allergy. Deceased at 3d PO
No complication
No complication
Rasmussen encephalitis Group 2 (n ⫽ 25)
2
6.0/F
18.9
L
No complication
13
9.7/M
17.5
R
No complication
15
2.6/F
3.3
R
No complication
20
5.7/F
10.6
R
No complication
23
7.8/F
14.5
R
No complication
24
2.0/F
4.2
L
No complication
26
1.2/M
8.7
R
No complication
35
13.5/M
16.1
L
No complication
45
4.3/F
5.9
R
No complication
49
13.0/F
22.7
L
No complication
ONS-24 | VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007
Seizure outcome
None
None
None
No Sz during 1yr PO,
then daily
None
None
Only 2 Sz at 4
mo PO
None
None
None
None
Decrease Sz (1/mo)
Decrease Sz intensity,
but still daily
None
None
No Sz during 8 mo PO,
then weekly
Decrease Sz, but still
weekly
None
Two episodes
of fall (possibly
Sz) at 8 yr PO
Stopped Sz after H
and no seizures
at 3 yr PO
None
No Sz during 8 yr PO,
then recurrence only
during night (stopped by
carbazepine)
None
None
Partial Sz
(1/mo to 1/wk)
Engel
grade
Vineland
communication
Ia
Ia
Ia
IVa
48
89
43
36
Ia
Ia
Ic
36
Not done
50
Ia
Ia
Ia
Ia
IIIa
IIIa
70
32
73
35
27
49
Ia
Ia
IIIa
70
78
47
IIIa
52
Ia
Id
20
45
IIc
27
Ia
IIa
73
19
Ia
Ia
IIIa
Not done
Not done
Not done
Not done
2.8
3.5
29.0
19.4
9.8
14.3
16.7
5.8
9.9
17.1
13.3
29.9
Stop Sz during 8 mo
PO, then weekly
IIIa
Not done
None
None
Ia
Ia
Not done
Not done
Not done
None
None
None
Only 4 Sz at 4 mo PO
None
None
None
None
None
Rare episodes of
loss of consciousness
with fall (stopped by
diazepam)
Ia
Ia
Ia
Ic
Ia
Ia
Ia
Ia
Ia
IIc
27
57
85
49
62
Not done
48
47
93
19
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VERTICAL PARASAGITTAL HEMISPHEROTOMY
TABLE 1. continued
Age at
Patient onset
no.
(yr)/sex
Age at
hemispherotomy (yr) Side
Postoperative course
Age at
evaluation (yr)
50
54
3.3/M
1.9/M
8.9
4.1
R
R
No complication
No complication
17.1
11.4
58
63
5.5/M
3.2/F
9.0
14.8
L
L
No complication
No complication
12.7
24.0
65
66
69
71
74
75
82
83
103
10.0/F
4.8/F
10.3/F
4.0/M
3.7/M
2.2/M
6.2/M
7.2/F
3.9/F
13.6
5.8
14.0
5.7
9.6
16.8
13.4
36.0
13.2
R
R
R
R
R
R
R
L
L
No complication
No complication
No complication
No complication
No complication
No complication
No complication
No complication
No complication
17.3
11.8
17.7
10.7
13.0
24.0
14.6
37.5
13.5
115
10.5/F
14.3
L
No complication
18.9
116
3.6/M
13.1
R
No complication
21.6
Sturge-Weber syndrome Group 3 (n ⫽ 10)
6
0.1/M
22.7
L
No complication
25.3
21
28
39
41
42
57
61
72
105
0.1/M
0.0/F
0.3/F
0.2/M
0.2/M
0.5/F
0.1/M
0.5/M
0.03/F
5.9
0.4
13.9
1.9
1.8
20.6
4.4
1.0
0.6
L
L
L
R
L
R
L
R
R
No complication
No complication
No complication
No complication
No complication
No complication
No complication
No complication
No complication
Ischemic-vascular sequelae Group 4 (n ⫽ 18)
3
0.08/M
6.0
R
No complication
4
0.3/F
20.5
L
Cutaneous infection of ear
5
0.4/M
11.3
R
No complication
7
1.7/M
13.5
R
No complication
10
0.6/M
5.9
R
No complication
18
0.5/M
20.0
L
Ventricul
19
0.01/F
2.5
L
SDPS
27
7.8/F
13.3
L
No complication
30
1.8/M
5.4
L
No complication
a
8.7
4.4
16.3
6.3
10.4
24.4
13.5
6.2
4.1
15.8
22.4
13.2
16.5
10.5
28.2
3.7
16.6
13.6
31
34
36
38
0.5/F
0.0/F
0.0/M
0.7/M
3.3
1.2
4.4
5.5
L
L
L
L
No complication
Ventricul
No complication
No complication
8.7
2.2
9.3
9.5
44
47
0.07/M
0.4/M
5.5
26.7
L
L
No complication
No complication
6.5
30.1
48
51
67
0.0/M
1.0/F
1.5/M
5.6
4.3
11.6
L
R
R
No complication
No complication
No complication
9.8
8.7
18.0
Seizure outcome
Engel
grade
None
No Sz during 4yr PO, then
rare left clonic seizure
(stopped by valproate)
None
Rare Sz during 3 yr
PO, then no Sz
None
None
None
None
None
None
None
None
Decrease Sz mainly
during night
Stop Sz during 2 yr PO, then
recurrence (1/mo–1/3 mo)
Stop Sz during 1 yr PO,
then recurrence mainly
during night
Vineland
communication
Ia
IIa
37
66
Ia
Ic
58
19
Ia
Ia
Ia
Ia
Ia
Ia
Ia
Ia
IIIa
Not done
Not done
Not done
Not done
Not done
Not done
61
57
Not done
IIa
40
IIIa
Not done
Fall on back at 3 mo and
1 yr PO (possibly Sz)
None
None
None
None
None
None
None
None
Partial Sz (<1/trim)
IIa
19
Ia
Ia
Ia
Ia
Ia
Ia
Ia
Ia
IIb
29
Not done
28
54
44
19
Not done
Not done
Not done
None
None
None
Left hemibody Sz rarely
None
None
TC Sz only with fever
None
Daily Sz and 2 status
epilepticus (stopped with
stiripentol)
None
None
None
Rare Sz after head injury
at 3 yr PO (stopped by
valproate)
None
No Sz during 6 mo PO,
then only during night
None
None
None
Ia
Ia
Ia
IIIa
Ia
Ia
IIb
Ia
IV b
19
20
31
Not done
34
19
51
74
19
Ia
Ia
Ia
IIa
39
68
49
47
Ia
IId
39
19
Ia
Ia
Ia
50
81
Not done
L, left; R, right; VPS, ventriculoperitoneal shunt; Sz, seizure; PO, postoperative; SDPS, subdural peritoneal shunt; ventricul, ventriculocysternostomy; H,
hemispherotomy; TC, tonic-clonic.
NEUROSURGERY
VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007 | ONS-25
DELALANDE ET AL.
A
FIGURE 2. Parasagittal (A), coronal (B),
and axial (C) MRI scans demonstrating
the lines of disconnection of the VPH.
Pre- (D) and postoperative (E) axial MRI
scans of Patient 43 demonstrating right
hemimegalencephaly with a large anterior part of the corpus callosum.
B
D
C
seizure frequency was daily or
weekly in 82% of the children.
Nine children underwent other
surgery before hemispherotomy,
which was inefficient on
seizures. These previous surgeries included focal resection
(Patients 12, 23, 53, 54, 58, 71, and 83), porencephalic cyst
uncapping (Patient 3), and complete callosotomy (Patient 25).
After hemispherotomy, 74% of the children (n ⫽ 60) were
seizure free (Engel Class I); among these, 76.6% (n ⫽ 46) were
free of antiepileptic drugs (Fig. 3). Ten children (12%) had rare
seizures (Engel Class II). Eleven children (14%) continued to
have seizures and were classified as Engel Class III (n ⫽ 9) or
Engel Class IV (n ⫽ 2). The results varied according to the etiology, but this variation was not statistically significant (Fig. 4).
In terms of seizure outcome, the best results were achieved in
patients with Rasmussen encephalitis and Sturge-Weber disease with 92 and 100% classified in Engel Class I or II, respectively. These percentages were 88 and 75%, respectively, for
ischemic-vascular sequellae and cerebral malformation. We did
not find any changes in the long-term outcome according to the
seizure frequency outcome. There was the same proportion of
patients classified as Engel Class I or II regardless of the duration of the follow-up period (Fig. 5).
The postoperative course was uneventful for 67 children
(80.7%). Transfusion was necessary in 8% of the children.
Thirteen children (15.7%) developed postoperative hydrocephalus, for which ventriculocisternostomy was performed in
two (Patients 34 and 18), ventriculoperitoneal shunt in seven
(Patients 11, 17, 29, 32, 43, 46, and 77), a subdural peritoneal
shunt in three (Patients 19, 33, and 55), and all three procedures in one child (Patient 52). One of the children who had
ventriculoperitoneal shunt placement developed a local wound
infection associated with meningitis (Patient 32). Another child
(Patient 77) developed severe intracranial hypertension 8 days
ONS-26 | VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007
E
postoperatively. She underwent external ventricular drainage,
then ventriculoperitoneal derivation, but remained in a bedridden state. The cerebral MRI scan, performed at 3 months postoperatively, exhibited a large area of low attenuation in the
frontoparietal region on the right side (contralateral to the side
of hemispherotomy) in keeping with an extensive cerebral
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VERTICAL PARASAGITTAL HEMISPHEROTOMY
TABLE 2. Medical characteristics according to etiologya
Etiology
Group 1 (MCD)
Group 2 (RE)
Group 3 (SW)
Group 4 (Seq)
P value
Age (yr) at onset of seizures (SD)
[min–max]
Age (yr) at hemispherotomy (SD)
[min–max]
Age (yr) at evaluation (SD)
[min–max]
Preoperative delay (yr) (SD)
[min–max]
Postoperative follow-up (yr) (SD)
[min–max]
0.2 (0.76)
[0–4.2]
3.7 (4.5)
[0.3–18.2]
7.4 (4.7)
[1.4–23.8]
3.4 (4.4)
[0.3–18.2]
4.3 (3.0)
[0.03–11.3]
5.9 (3.5)
[1.3–13.5]
12.6 (7.0)
[3.3–36.0]
17.2 (7.2)
[5.7–37.5]
6.7 (6.0)
[0.7–28.7]
4.7 (2.9)
[0.3–10.2]
0.3 (0.2)
[0.04–0.6]
7.3 (8.6)
[0.4–22.7]
12.0 (7.8)
[4.1–25.3]
7.1 (8.5)
[0.3–22.5]
4.6 (2.4)
[2.5–9.0]
1.0 (1.8)
[0–7.8]
9.2 (7.1)
[1.2–26.7]
13.5 (7.6)
[2.2–30.1]
8.5 (7.1)
[1.2–26.2]
4.2 (2.6)
[0.9–9.7]
<0.0001
<0.0001
<0.0001
0.04
0.96
a
MCD, multilobar cortical dysplasia; RE, Rasmussen encephalitis; SW, Sturge-Weber syndrome; Seq, ischemic-vascular sequelae; SD, standard deviation ; min, minimum;
max, maximum.
infarction. Postoperatively, three children died (3.6%), two of
them within the first week after hemispherotomy. An 11-yearold boy (Patient 78) developed severe diabetes insipidus with
refractory hypernatremia and died on the fourth postoperative
day. A 15-year-old girl (Patient 80) died 3 days postoperatively
owing to a latex allergy (diapers). The third child, a 2-year-old
girl (Patient 79) with hemimegalencephaly, was reoperated (by
the same neurosurgeon) 18 months after the first hemispherotomy for recurrent seizures. This was the only child in our
series who underwent a ”second-look” surgery for persisting
or recurring seizures. As the hemispherotomy was intraoperatively proved to be complete in this case, it was not necessary
to perform any other surgical procedure, and the girl was
uneventfully discharged at home 10 days postoperatively. She
was, however, rehospitalized 1 month later in a context of
infectious disease (fever, otitis, gastroenteritis) and clinical deterioration rapidly occurred, requiring intensive care 4 days later.
She died 8 days after the onset of her symptoms. The family
refused autopsy.
The hemiparesis was more important in the upper extremity.
Sixty-one children (84%) were able to walk alone or with help,
and the ability to walk was preserved in all the children who
walked alone before surgery. Among the children who did not
acquire independent walk (n ⫽ 12), seven were in the youngest
patient group (< 4 yr at evaluation). Four children had a severe
mental deficiency associated with multiple cortical dysplasia
and one had Rasmussen encephalitis (Patient 63), but lost the
ability to walk several years before surgery. When hemispherotomy was performed early in life, the ability to walk was
acquired between the age of 19 months and 4 years 4 months.
The degree of spasticity of the hemiparetic limbs was different
in the RE and the Seq groups than in the other two groups.
Whereas the wrist was retracted in the majority of the first two
groups (58 and 64%, respectively), the joints showed only a
slight retraction or were suppler in most patients in the latter
two groups (85%). When testing the ability of the hemiparetic
upper limb, 61% were able to put the hand on the head and
30% on the back; none of the children was operated on for this
NEUROSURGERY
FIGURE 3. Bar graph showing the outcome of the whole population with
respect to seizures (mean follow-up period, 4.4 yr; SD, 2.7 yr).
FIGURE 4. Bar graph showing outcome seizure versus etiology.
FIGURE 5. Bar graph showing the global seizure outcome (Engel classification) according to the duration of the follow-up period.
VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007 | ONS-27
DELALANDE ET AL.
guage in 91 and 82%, respectively, but a worsening in motor
function in 26%, particularly concerning the hand function on
the hemiparetic side.
Vineland Adaptive Behavior Scale
FIGURE 6. Scatterplot showing the Vineland communication score versus
preoperative delay.
spasticity. Ten children (14%) acquired voluntary prehension of
the hand on the hemiparetic side and were able to grab a small
object (e.g., a pencil). Nevertheless, none of them had fine prehension (thumb-index pincer) or the ability to put a pearl in a
bottle. Thirty-six percent of the children were able to hold a
small object, and the remaining 50% had no finger movement.
Weight was normal in 77%, height in 80%, and HC in 81%.
A low weight (<2 SD) was observed in 7% of the children, a low
height in 12%, and a low HC in 12%. For these three parameters, an increase (>2 SD) was observed for 9, 8, and 7%, respectively, of the children postoperatively.
For sixty-nine patients, we obtained sufficient data concerning school placement and re-education schedules. Considering
their routine daily life, all of them had several types of reeducations each week. According to age, thirty-three children
(56%) between 3 and 20 years of age (n ⫽ 59) were able to go
to school. Among them, 13 were in normal school (nine in
nursery school and four in elementary school) and 20 were in
specialized schools. Twenty-six (44%) were in an institution.
After the age of 20 (n ⫽ 10), all of them were in an institution
except one who was in protected employment. Globally, when
we asked the parents how they evaluated the outcome of the
child, they reported an improvement in behavior and lan-
These results concern 58 out of 65 French patients. Seven
patients were not included, either because the families were not
reliable (Patients 7, 14, and 28) or the patients could not be
reviewed (Patients 61, 78, and 79). We did not analyze the
results of Patient 83 because she had lobar resection 10 years
before hemispherotomy (Fig. 6; Tables 3 and 4).
The mean Vineland Composite Score was low (43 ⫾ 15) compared with the norm (100 ⫾ 15), but with heterogeneity according to the domain. The children achieved higher scores in socialization (57 ⫾ 19) compared with communication (45 ⫾ 20) or
daily living skills (41 ⫾ 21) (P ⬍ 0.0001). For the socialization
and communication domains, there was a wide range of scores,
ranging from 19 to 89. The lowest score was observed for motor
skills (39 ⫾ 14). For instance, no child was able to ride a bicycle without training wheels or catch a small ball from a distance
of 10 feet.
According to the side, children with right hemispherotomy
showed a better communication score than children with left
hemispherotomy. As a function of etiology, the Rasmussen
group had the best results in all four domains (Table 3).
Preoperative delay was negatively and significantly associated to all the Vineland scores, except for motor skills. The
longer the duration of epilepsy, the lower the scores (Fig. 6;
Table 4). This relation was similar in right and left hemispherotomy, and it was observed in all four etiological groups.
However, it was especially strong in Group 1 (MCD), Group 2
(RE), and Group 3 (SW). Considering the MCD and SW groups
(n ⫽ 27) with early onset of seizures, nine had a Vineland communication score of more than 50; of them, eight (91%) had a
preoperative delay less than 2 years. Inversely, in the RE and
Seq groups (n ⫽ 30), 18 had a Vineland communication score
less than 50; of them, 14 (78%) had a preoperative delay of
more than 4 years.
TABLE 3. Results of the Vineland scalea
No. of patients
Communication
Daily living skills
Socialization
Motor skills
Global score
Total (SD)
58
45 (20)
41 (21)
57 (19)
39 (14)
43 (15)
Side
Right (SD)
Left (SD)
24
34
52 (22)b
41 (19)b
43 (21)
40 (22)
59 (20)
55 (20)
53 (21)
46 (20)
47 (18)
41 (16)
Etiology
G1: MCD (SD)
G2: RE (SD)
G3: SW (SD)
G4: Seq (SD)
21
15
6
16
49 (20)
51 (21)
32 (14)
41 (20)
40 (20)
53 (24)
31 (14)
36 (19)
58 (17)
62 (19)
50 (26)
54 (23)
40 (14)c
64 (23)c
42 (18)c
53 (20)c
43 (15)
51 (18)
35 (15)
40 (17)
a
SD, standard deviation; MCD, multilobar cortical dysplasia; RE, Rasmussen encephalitis; SW, Sturge-Weber syndrome; Seq, ischemic-vascular sequelae.
P ⫽ 0.04.
c
P ⫽ 0.004.
b
ONS-28 | VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007
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VERTICAL PARASAGITTAL HEMISPHEROTOMY
TABLE 4. Vineland statistical analysisa
Medical characteristics
Communication
Daily living skills
Socialization
Motor skills
c
Global score
Age onset of seizure
Preoperative delay
Postoperative follow-up
0.06
–0.61e
–0.37d
0.20
–0.47d
–0.34c
0.04
–0.44d
–0.18
0.39
0.10
–0.23
0.16
–0.51e
–0.31b
Right side
(n ⫽ 24)
Age at onset of seizure
Preoperative delay
Postoperative follow-up
0.31
–0.65d
–0.02
0.39
–0.44b
–0.14
0.26
–0.52b
–0.08
0.58c
0.07
–0.16
–0.37
–0.54c
–0.06
Left side
(n ⫽ 34)
Age at onset of seizure
Preoperative delay
Postoperative follow-up
–0.17
–0.62d
–0.48c
0.08
–0.45c
–0.40b
–0.11
–0.37b
–0.21
0.26
0.12
–0.29
0.005
–0.47c
–0.38b
Group 1 (MCD)
(n ⫽ 21)
Age at onset of seizure
Preoperative delay
Postoperative follow-up
0.13
–0.59c
–0.60c
0.12
–0.53b
–0.58c
–0.06
–0.61c
–0.33
0.02
–0.35
0.28
0.07
–0.59b
–0.54b
Group 2 (RE)
(n ⫽ 15)
Age at onset of seizure
Preoperative delay
Postoperative follow-up
–0.29
–0.70c
–0.26
0.27
–0.60b
–0.46
–0.52b
–0.57b
0.003
–0.16
–0.43
–0.36
–0.10
–0.78d
–0.35
Group 3 (SW)
(n ⫽ 6)
Age at onset of seizure
Preoperative delay
Postoperative follow-up
–0.20
–0.93c
0.61
0.21
–0.76
0.51
0.31
–0.60
0.03
0.67
–0.09
–0.06
0.03
–0.87b
0.49
Group 4 (Seq)
(n ⫽ 16)
Age at onset of seizure
Preoperative delay
Postoperative follow-up
0.01
–0.62b
–0.43
0.06
–0.41
–0.48
–0.15
–0.34
–0.36
0.16
0.29
–0.25
–0.003
–0.46
–0.045
Total (n ⫽ 58)
Side
Etiology
a
MCD, multilobar cortical dysplasia; RE, Rasmussen encephalitis; SW,
Sturge-Weber syndrome; Seq, ischemic-vascular sequelae.
b
P < 0.05.
c
P < 0.01.
d
e
P < 0.001.
P < 0.0001.
This is a large population of children with epilepsy treated
by hemispheric disconnection with the same surgical approach
and conducted by the same surgeon. Moreover, we were able
to obtain recent data for 94% of the operated patients with an
important long-term follow-up period. In this article, we
described the VPH. We assume that with this vertical
approach, a complete disconnection of the affected hemisphere
can be achieved and that it offers the advantage of a clear
intraoperative assessment of completeness of the hemispherotomy and preservation of an intact vessel supply. Moreover,
the incision is limited to the minimum necessary cut to reach
to a functional exclusion of the entire hemisphere by respecting the same section as in anatomic hemispherectomy. This
technique ensures that the anatomic landmarks take into
account the surgical concept of a central core of the hemisphere proposed by Wen et al. (31). The central core of a hemisphere consists of the extreme, external, and internal capsules,
claustrum, lentiform and caudate nuclei, and thalamus.
Externally, this core is covered by the insula and surrounded
by the fornix, choroid plexus, and lateral ventricle. Wen et al.
(31) proposed key anatomic landmarks for hemispherotomy
techniques that can be used to disconnect the hemisphere from
its lateral surface around the insula, through the lateral ventricle, and toward the midline. The parasagittal approach realizes
the incision around the central core and makes it easier to
assess the completeness of the disconnection. In our popula-
NEUROSURGERY
VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007 | ONS-29
The age at the onset of seizures was not significantly related
to the Vineland scores, except for motor skills. The later the
onset of epilepsy, the better the motor skills score (P ⬍ 0.01).
In the total population, the postoperative follow-up period
was negatively correlated with the composite communication
and daily living skills scores. The longer the follow-up period,
the lower the scores. However, this relation was dependent on
the side, being significant only for patients undergoing left
hemispherotomy, and on the etiological group, being significant only in the MCD group. In this group, the discrepancy
between chronological age and mental age, as evaluated by the
Vineland scale, increased with the duration of the postoperative follow-up period.
DISCUSSION
DELALANDE ET AL.
tion, only one child (Patient 79) underwent reoperation for
seizure recurrence, despite no signs of incomplete disconnection on the postoperative MRI scans. The hemispherotomy
was intraoperatively proven to be complete and no other surgical procedure was performed.
Compared with the three techniques of lateral hemispherotomy (24, 25, 27), the interruption of the associative and commissural neuronal fibers is complete because the incision is
the same as in the anatomic hemispherectomy (18). It allows a
complete disconnection, including the insular cortex, when
the lateral approaches require its removal. Furthermore, all
the incisions are in a vertical plane. Therefore, it seems more
logical to achieve surgery through a vertical route. The long
distance between the surface and the deep incisions are not a
disadvantage with modern microscopes and a relatively thin
ultrasonic aspirator. Moreover, our technique allows the
utmost degree of vessel preservation within the disconnected
hemisphere (middle cerebral artery and main venous drainage
systems), reducing the risk of brain swelling secondary to
ischemia (6). In the “modified” lateral hemispherotomy
described by Cook et al. (3), the principle of this technique
was to create a working space around the ventricular system
by removing most of the thalamus, basal ganglia, and caudate
nucleus associated with early ligation of the MCA. This technique was compared with anatomic and functional hemispherectomy and resulted in fewer perioperative risks and a
shorter hospital stay than the two older techniques.
Postoperative mortality and morbidity was reported in detail
by Cook et al. (3) and Jonas et al. (14), who compared the
advantages and disadvantages associated with each hemispherectomy technique (anatomic, functional, and modified
lateral hemispherectomy). They demonstrated that modified
lateral hemispherotomy seemed to have the lowest complication rate (35, 34, and 11%, respectively) and a reduced necessity of shunt (78, 9.4, and 22%, respectively), even if the modified lateral hemispherotomy technique suggests a higher
shunt rate than that with the functional hemispherectomy
technique. In our population treated by VPH, the necessity for
shunt placement was 16% (the complication rate for the others
was 6%), suggesting that this technique is successful in
improving the safety of hemispherotomy technique.
Compared with the other disconnection techniques, VPH can
be easier to perform in the group of patients with hemispheric
cortical cerebral dysgenesis associated with “catastrophic
epilepsy.” These children exhibit seizures, beginning in the
first weeks of life, which are usually uncontrolled by the
antiepileptic drugs, and evolving in refractory epilepsy with a
poor intellectual outcome. It seems, therefore, important to
propose an early, safe, and reliable hemispheric disconnection.
We have pointed out that shunt placement was necessary in 13
children (16%), among them were 10 in the MCD group (33%
of Group 1) and three in the Seq group (17% of Group 4), but
none in the two other groups. It is difficult to understand why
hydrocephaly is so common in the hemimegalencephaly population. The intraoperative evidence of an abnormal deep
venous drainage that is interrupted could be an explanation,
ONS-30 | VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007
but we have never seen any brain swelling that should happen
in such a situation.
Concerning the efficacy on seizures, 74% of the patients were
seizure-free with no seizure recurrence in a long-term followup period and no necessity to reoperate. Among the surgical
techniques for epilepsy, hemispherectomy and hemispherotomy carry the best results in terms of seizure freedom, which
permits, after a sufficient follow-up period, the reduction and
termination of antiepileptic drug treatment in a high percentage of patients. In our population, we successfully stopped
antiepileptic drug treatment in 77% of the group classified as
Engel Class I.
The factors affecting seizure control are not completely elucidated, but several authors have suggested that differences in
etiology, as well as the technique of hemispheric disconnection, explains a portion of this variability. Globally, with lateral
hemispherotomy, the rate of patients becoming seizure-free
has been indicated to be between 68 and 88% (14, 28). For the
modified lateral hemispherotomy, there was a seizure-free outcome in the first 2 postoperative years of 82.7 and 66.7% in
patients with cortical dysplasia and Rasmussen encephalitis,
respectively. However, the score decreased at 5 years postoperatively to 60.5 and 62.5% (14). The largest study on seizure
outcome was reported by Holthausen et al. (11) in a population of 333 hemispherectomies from 13 different centers with a
minimum follow-up period of 6 months. The percentage of
seizure-free patients was better in the “hemispherotomy” techniques (85.7% were seizure-free) and in the group of patients
including Rasmussen, Sturge-Weber, and vascular insults
(94.6% became seizure-free). The other group of patients,
including cerebral dysplasia and other etiologies (sequellae of
infections, postmeningitis, postencephalitis) became seizurefree in 68% of the cases.
In our population, Groups 2 (RE), 3 (SW), and 4 (Seq) also
presented the best result on seizure outcome with 80, 80, and
78%, respectively, being graded as Engel Class I. It should be
mentioned that patients classified in Group 4 concerned various origins of ischemic lesions, among them ischemic perinatal
lesions, hemorrhage, postinfectious, and hemiconvulsion hemiplegia epilepsy syndrome. Some of these patients could be classified as other or “miscellaneous” in some studies, which may
explain why we do not have as good a result as in the two
other groups. Moreover, because the resection of the cortex was
standardized in the frontal area according to the vertical
approach, but not primarily directed to the anatomopathological diagnosis, it was not possible to make extensive pathological examination for this group.
Finally, the MCD group had the least favorable outcome,
with only 66% of patients becoming seizure-free. This group
also had the highest rate of postoperative shunting (33%). In
this group of etiology, there is some difficulty proving that the
opposite hemisphere is not affected because there are bilateral
interictal EEG abnormalities, and sometimes bilateral neuropathological changes following autopsy (13, 23).
Considering the group of children who had undergone surgery before hemispherotomy, seven had focal resection, one
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VERTICAL PARASAGITTAL HEMISPHEROTOMY
had callosotomy, and one had surgery for a porencephalic cyst.
Among the seven children undergoing focal resection, five presented with a Rasmussen encephalitis (20% of the RE group)
and hemispherotomy was avoided to preserve hand motor
function because the children were not yet hemiplegics.
However, focal surgery was not efficient because these children remained with frequent epileptic seizures. Therefore, it
seemed that the indication of hemispherotomy could be considered in patients with Rasmussen syndrome, even without a
complete hemiparesis, but with progressive neuropsychological alterations and/or frequent status epilepticus (29).
According to the global long-term evolution assessed by the
Vineland scale, we found a strong correlation between the preoperative delay and global long-term outcome according to the
three domains of communication, socialization, and daily life
ability. The shorter the duration of the seizures, the better the
postoperative status of the child in all four etiological groups.
These results corroborated with those of Jonas et al. (14), who
used the Vineland scale in the postoperative course in a population of 52 children treated by hemispherectomy or hemispherotomy. They suspected that patients with seizure duration
of 3 years or less had a better outcome. In our series, we confirmed the significance of performing surgery early after the
onset of seizures and proposed to decrease the preoperative
delay to 2 years or less, especially in children with MCD and
SW who have seizure onset early in life.
Although these children made significant progress in the
development, we found a negative correlation between the
postoperative follow-up duration and the Vineland score, but
only in the group of children in whom hemispherotomy was
performed on the left side. These children tended to have a
less impressive outcome because the discrepancy between
chronological age and mental age, as evaluated by the
Vineland scale, increased with the duration of the postoperative follow-up period. To our knowledge, we are the first to
report on the effect of the long-term follow-up periods on
global development. We may hypothesize that, in this group of
children, the right hemisphere tends to be unable to develop
the same abilities as the left side in the domain evaluated by
the Vineland scale.
Regarding correlation with global outcome, we should
acknowledge that there may be other confounding factors (e.g.,
preoperative cognitive development, antiepileptic drug, delay
coming to surgical attention), which could interfere with prognosis, independent of when the surgery is performed. Further
prospective studies are needed.
CONCLUSION
VPH is a surgical procedure for hemispheric disconnection
that, with a low rate of complications, seems to be at least as safe
as the other common procedures. Moreover, this procedure
allows the achievement of good control for seizures, with 74% of
the patients becoming seizure-free. This procedure must be proposed as soon as possible after the onset of epilepsy when a
NEUROSURGERY
hemispheric syndrome has been precisely documented.
Prospective studies should be conducted to confirm these results
on a larger population and with longer outcome duration.
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Acknowledgments
This work was supported by Pfizer Laboratory (MS, MN). We thank Francine
Lussier, M.D., Ph.D. (Montreal, Canada) for translation into the French version
of the Vineland Adaptative Behavior Scale, Maryse Lassonde, Psy, Ph.D.,
(Montreal, Canada) for advice, and Philippe Mercier, M.D., Ph.D. (Angers,
France) and Etienne Delalande (Paris, France) for help with the figures.
ONS-32 | VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007
COMMENTS
T
he authors provide a retrospective study on a series of 83 cases
using the vertical parasagittal hemispherotomy technique. This
technique provides seizure outcome and complication rates comparable
to other contemporary series of hemispherotomy and functional hemispherectomy. However, the shunt rate is somewhat higher (> 16%).
After the initial publication (1), this is the first article in which the reader
can easily follow the description of the surgical technique itself.
Devin Binder
Johannes Schramm
Bonn, Germany
1. Delalande O, Pinard JM, Basdevant C: Hemispherotomy: A new procedure for
central disconnection. Epilepsia 33 [Suppl 3]:99–100, 1992.
T
hese authors have much experience and success with this particular hemispheric disconnection technique. As I have learned from
the patients in this study, the important factor is getting the hemisphere disconnected with the least amount of trauma to the patient as
possible. The authors report their wonderful outcomes in terms of both
seizure-free and complication rates. It is important for the epilepsy
surgeon to appreciate the individuality of each patient who is a candidate for hemispheric disconnection and to apply the most suitable technique for that patient. For example, minimally invasive techniques
may be more suitable for patients with perinatal stroke, whereas a
modified functional or anatomic technique may be better suited to
patients with hemimegalencephaly. Regardless, the surgeon must be
comfortable with the technique performed and this requires adequate
training and ongoing experience in the surgical care of these patients.
William E. Bingaman
Cleveland, Ohio
www.neurosurgery-online.com