Neurosurgery 2007_ Pons19

NEUROSURGERY VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007 | ONS-19

OPERATIVE TECHNIQUES

Among the patients who experiencedpharmacologically refractory seizuresassociated with a clinical hemisphericsyndrome owing to a diffuse pathology of onecerebral hemisphere (21), functional hemi-spherectomy presents an effective surgical pro-cedure and has the highest rate of seizure con-trol (9, 31). Approximately 77 to 80% of thepatients who underwent an operation wereseizure-free in the first reported series. Such asurgical procedure has been largely proposedin children with catastrophic epilepsy associ-ated with a congenital or acquired hemisphericcerebral pathology. The classical procedure ofanatomic hemispherectomy (5, 15, 17) was pro-gressively abandoned by neurosurgeons to

avoid long-term complications or, in somecases, fatal outcomes, mainly owing to cerebralhemosiderosis that resulted from dead spaceproduced by removal of the entire hemisphere(10, 16, 19, 22), as well as immediate postoper-ative risks such as considerable intraoperativeblood loss (3, 20). Adams (1) proposed to turnsubdural dead space into epidural dead space.In 1983, functional hemispherectomy was intro-duced by Rasmussen (22) based on a combina-tion of partial anatomic excision and discon-nection of the remaining lobes. Furthermore,hemidecortication was proposed by removingonly the gray matter, sparing as much as possi-ble of the white matter and avoiding openingof the ventricle (2, 12, 32, 33). However, the effi-

Olivier Delalande, M.D.Fondation OphtalmologiqueA. de Rothschild,Pediatric Neurosurgery Unit,Paris, France

Christine Bulteau, M.D.Fondation OphtalmologiqueA. de RothchildPediatric Neurosurgery Unit,Paris, France

Georges Dellatolas, M.D., Ph.D.INSERM U 472,Biostatistic and Epidemiology Unit,Hpital P. Brousse,Villejuif, France

Martine Fohlen, M.D.Fondation OphtalmologiqueA. de Rothschild,Pediatric Neurosurgery Unit,Paris, France

Claude Jalin, M.D.Fondation OphtalmologiqueA. de Rothschild,Pediatric Neurosurgery Unit,Paris, France

Virginie Buret, Psy.Fondation OphtalmologiqueA. de Rothschild,Pediatric Neurosurgery Unit,Paris, France

Delphine Viguier, M.D.INSERM U 472,Biostatistic and Epidemiology Unit,Hpital P. Brousse,Villejuif, France

Georg Dorfmller, M.D.Fondation OphtalmologiqueA. de Rothschild,Pediatric Neurosurgery Unit,Paris, France

Isabelle Jambaqu, Psy., Ph.D.Universit Paris Descartes,Laboratoire Cognitionet Comportement,Cedex, France

Reprint requests:Olivier Delalande, M.D.,Fondation OphtalmologiqueA. de Rothschild,Service de Neurochirurgie Pdiatrique,2529 rue Manin,75940 Paris Cedex 19-France.Email: [email protected]

Received, March 24, 2006.

Accepted, September 8, 2006.

VERTICAL PARASAGITTAL HEMISPHEROTOMY:SURGICAL PROCEDURES AND CLINICAL LONG-TERMOUTCOMES IN A POPULATION OF 83 CHILDREN

OBJECTIVE: Hemispherotomy techniques have been developed to reduce complicationrates and achieve the best possible seizure control. We present the results of our pedi-atric patients who underwent vertical parasagittal hemispherotomy and evaluate thesafety and global long-term outcome of this technique.METHODS: Eighty-three patients underwent vertical parasagittal hemispherotomy bythe same neurosurgeon (OD) between 1990 and 2000. We reviewed all patients between2001 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 per-formed with the classic hemispherectomy, while leaving the majority of the hemisphereintact 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 resultsvaried according to the etiology, but this variation was not statistically significant. Theearly postoperative course was uneventful for 94% of the children, and shunt place-ment was necessary in 15%. We found a correlation between the preoperative delay andthe Vineland Adaptive Behavior score: children with a longer duration of seizures hadlower performances.CONCLUSION: Vertical parasagittal hemispherotomy is an effective surgical techniquefor hemispheric disconnection. It allows complete disconnection of the hemispherethrough a cortical window with good results in terms of seizure outcome and a com-parably low complication rate.

KEY WORDS: Children, Epilepsy surgery, Hemispherectomy, Hemispherotomy, Long-term outcome

Neurosurgery 60[ONS Suppl 1]:ONS-19ONS-32, 2007 DOI: 10.1227/01.NEU.0000249246.48299.12

ONS-20 | VOLUME 60 | OPERATIVE NEUROSURGERY 1 | FEBRUARY 2007 www.neurosurgery-online.com

DELALANDE ET AL.

ciency of this technique on seizure control was diminished,especially in the group of children with diffuse cortical dyspla-sia (4). To further decrease complication rates, new surgical pro-cedures have been developed that reduce the volume of brainremoval and increase the ratio of disconnection to resection.These surgical techniques require a smaller skin incision andbone flap, which offers the advantages of reducing blood lossand avoiding the exposure of large venous sinuses. This conceptreplaces the term hemispherectomy with hemispherotomy,as proposed by Olivier Delalande in 1992 (7).

Various modifications of the hemispherotomy have beendescribed (3, 7, 8, 24, 25, 27, 28). The peri-insular hemisphero-tomy proposed by Villemure and Mascott (28) and the so-calledmodified lateral hemispherotomy (3) are the largest reportedseries to date. However, they are more difficult to perform inchildren born with cerebral malformation (hemimegalen-cephaly or cortical dysplasia) because of abnormal brainparenchyma and ventricular anatomy. Moreover, in theseseries, different hemispherectomy techniques were appliedwith a relatively short-term follow-up period and small num-ber of patients. Holthausen et al. (11) reported on the largestretrospective multicenter study to date. In that study, there wasa complete disappearance of seizures in approximately 50 to70% of the patients. The surgical technique with the best resultswas the hemispherotomy technique. But, long-term postop-erative outcome (5 yr) seems to be less effective, with adecrease of seizure-free patients from 76% at 1 year postoper-atively to 58% at the time of the 5-year follow-up examination(14). Moreover, it is accepted that postoperative seizure out-come is influenced by the underlying pathology, with the worstoutcome in the group of hemispheric cortical dysplasia com-pared with patients with Sturge-Weber syndrome, Rasmussenencephalitis, or vascular insults.

We present the vertical approach of hemispherotomy thatwe have used for the past 15 years, which differs from the pre-vious techniques in two main aspects: 1) the major principle isto further reduce the extent of brain resection by increasing theamount of disconnection, thereby introducing the concept ofhemispherotomy and 2) the use of the vertical approach ratherthan the lateral approach offers the possibility of doing exactlythe incisions performed in anatomic hemispherectomy, basedon reliable landmarks. This allows the surgeon ensure that aneffective total disconnection of the hemisphere is achieved. Thetechnique that we propose to call vertical parasagittal hemi-spherotomy (VPH) is described in this article because it differsfrom the previous surgical techniques of functional hemi-spherectomy. The aim of this retrospective study is to report onour results of a large population of children operated by thesame surgical technique (VPH) and by the same neurosurgeon(OD) to appreciate the safety of this technique and evaluate theglobal long-term outcome.

PATIENTS AND METHODS

The patient is operated on in the supine position with thehead in a neutral position, but slightly elevated in the horizon-

tal plane. A small parasagittal frontoparietal craniotomy(approximately 3 5 cm, 1 to 2 cm from the midline, one-thirdanterior and two-thirds posterior to the coronal suture) is per-formed with the posterior frontal and central region exposed(Fig. 1A).

A limited cortical resection of approximately 3 2 cm is per-formed, reaching the ependyma of the ventricular roof (Figs.1B, 1C, 2, and 3). The ventricle is opened, thereby delineatingthe midline region as well as the posterior aspect of the thala-mus, and anteriorly the foramen of Monro.

Following the roof of the lateral ventricle mesially, the corpuscallosum is identified. By using the ultrasonic aspirator with alow level of vibration (1020%), the callosal resection is firstperformed posteriorly towards the splenium (Figs. 1B, 1C, 2,and 3). The midline is always easy to find at this level becausethe falx cerebri is close to the upper part of the splenium. Theresection of the splenium has to be pursued until the roof of thethird ventricle and the arachnoid of the cisterna ambiens areexposed. Then, the posterior column of the fornix is cut at thelevel of the ventricular trigone, from the arachnoid of the cis-tern ambiens reaching laterally to the choroidal fissure, behindthe pulvinar (Figs. 1F, 1G, and 2). The next step consists of per-forming an incision lateral to the thalamus. Posteriorly, there isno connection at the level of the ventricular trigone. Laterally,one can see the posterior part of the choroid plexus of the tem-poral horn (Figs. 1F, 1G, and 2), which serves as a guide for theincision lateral to the thalamus. This incision is performedstrictly vertically and extends from the trigone to the most ante-rior part of the temporal horn (Figs. 1I, 1J, 2, 3, 4, and 5), byunroofing the temporal horn entirely, anterior to the coronalplane of the foramen of Monro (cpfM). The incision has toremain within the white matter as laterally as possible to avoidany damage to the lateral aspect of the thalamus.

As a next step, the completion of the callosotomy is achievedanteriorly, thereby resecting the genu until just above the ante-rior commissure (Figs. 1O, 1P, and 2). Just as for the posteriorpart of the corpus callosum, the section is performed intracal-losally to the interhemispheric cistern. The pericallosal arteries(pca) are most often seen through the pia mater. The resectionof the genu through the ventricular roof most often requireslifting the patient up to have good visibility anteriorly.

It is then necessary to resect the most posterior part of thegyrus rectus (Figs. 1R and 1S). This resection allows one tovisualize, across the arachnoid, the first segment of the anteriorcerebral artery (aca) and the optic nerve (on), and providesspace for a straight incision oriented anterolaterally through thecaudate nucleus towards the anterior part of the lateral incision(Figs. 1T, 1U, 2, 3, and 4). This last dissection will cut all the con-nections from the anterior temporal lobe, the amygdala, andthe frontal lobe. The hemispherotomy is now complete, havingisolated the entire epileptic cortex from the subcortical struc-tures (Fig. 2A). The whole disconnection is easily performedwith the ultrasonic aspirator and with minimal hemorrhage.Perforating arterial branches from the anterior and middle cere-bral artery can be easily spared by using a low level of vibra-tion. On the outside, there may be venous bleeding, particu-

larly in cases of hemimegalencephaly, but this bleeding is rarelyconsiderable and is usually easily controlled.

Two modifications have been implemented since this tech-nique was initiated. The cortical window initially reached themidline. This made the callosotomy easier, but it was then usu-ally necessary to cut large veins close to the sagittal sinus. Thecortical window was displaced laterally as described above.Using the lateral approach, it is always possible to spare largeveins; a smaller vein can be sacrificed, provided it only drainsthe cortical region to be removed. The size of the window hasbeen considerably reduced in all cases except for hemimegalen-cephaly. In the latter cases, the thickness of the brain andanatomic abnormalities make the procedure more difficult, anda larger route is a condition to avoid any damage to the remain-ing brain. In hemimegalencephaly, the shape of the anteriorpart of the corpus callosum is sometimes large and/or thefrontal horn of the lateral ventricle might be atretic (Fig. 2, Band C). One has to keep in mind that the anatomic guidelinesare the upper part of the corpus callosum and the midline arter-ies. A careful analysis of the three-dimensional anatomy of theaffected hemisphere has to be done in cases of hemimegalen-cephaly and some rare cases of complex hemispheric dysplasia.One must be aware that the brain midline cannot be in the cra-nial midline. In all of the cases we have encountered, the falxcerebri posteriorly, the roof of the temporal horn laterally, andthe pericallosal arteries anteriorly are always remarkable land-marks that should be followed. In all other indications, hemi-spheric atrophy and lack of change of gross anatomy makes theprocedure easy, allowing a narrower route.

The hemispherotomy dissection has to be large enough tobe assessed by axial and coronal magnetic resonance imag-ing (MRI) scans. All the children in this series had MRI scansat 3 months postoperatively to exclude complications such asactive hydrocephalus or subdural hygroma. The line of thehemispheric disconnection was visible on the axial, sagittal,and coronal planes in all cases (Fig. 2A).

We performed a retrospective study of all patients whounderwent hemispheric disconnection for hemispheric refrac-tory epilepsy between April 1990 and September 2000. Eighty-three patients underwent hemispherotomy by the same surgicaltechnique (VPH) and by the same neurosurgeon (OD).Preoperative evaluation included clinical, neurophysiological(video electroencephalographic [EEG] telemetry), and neurora-diological (MRI) investigations in all patients with or withoutneuropsychological testing, single-photon emission computedtomography, Wada testing, and functional MRI scans. All datawere discussed at our multidisciplinary staff conferences. Sixty-five children were from France and 18 were from other coun-tries. Postoperative follow-up examinations were performedat 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 evalua-tion, depending on the evolution, until the end of theantiepileptic drug treatment. To analyze the long-term neuro-logical, cognitive, and social outcome of this large population,we have reviewed all French patients and have included an


VERTICAL PARASAGITTAL HEMISPHEROTOMY

external medical assessment of our foreign population in theperiod from December 2000 to June 2003.

We reviewed the French patients during a 2-day hospital-ization at our institution for a standard global evaluation,including seizure outcome, postoperative course, neurologi-cal examination, behavioral outcome, and cognitive assessment.Seizure outcome was assessed using the Engel classification(9). Neurological examination included ability to walk andspeak, motor and sensibility function, height, weight, head cir-cumference (HC), developmental milestones before and aftersurgery, type of schooling, weekly rehabilitation schedule,socioprofessional status of parents, and systematic question-ing of the parents to evaluate the progress in terms of language,motor, behavior, and any other problems that they hadobserved since hemispherotomy. We also recorded preopera-tive data (age of onset of seizures, type of seizures, frequencyof seizure at the time of surgery, psychomotor developmentand clinical status of the child, EEG, and MRI scans) from themedical file of each patient. Behavioral outcome was evalu-ated using the Vineland Adaptive Behavior Scale (26). Thisscale is well known to assess four behavioral domains (i.e.,communication, socialization, daily living skills, motor skills)in handicapped individuals from birth to adulthood andrequires only the information provided by the caretaker of thepatient, but not the direct involvement of the child. For allnon-French patients, we sent a medical file to the referringepileptologist in each country to analyze the epilepsy andantiepileptic drug treatment and neurological and globalsocial outcome. We present the results of the whole populationwith respect to seizure outcome, surgery related events, globalneurological long-term outcome, and Vineland score assess-ment.

Statistical AnalysisStatistical analysis was performed using SAS software (SAS

Institute, Cary, NC). The analysis focused on factors associatedwith the Vineland scores (composite and specific scores),indicating functional outcome. The main associated factorsexamined were etiological group, age at onset of the seizures,preoperative delay, postoperative follow-up, and the side ofthe hemispherotomy. The general linear model procedurewas used for relations between categorical and continuousvariables; the Spearman Rho was used for relations betweencontinuous variables.

RESULTS

Of the 83 patients (45 boys and 38 girls), 43 (52%) underwenta left hemispherotomy and 40 a right hemispherotomy. Themean age of onset of seizure was 2.1 years (standard deviation[SD], 3.3 yr; range, 0.013.5 yr), the mean age at hemisphero-tomy was 8 years (SD, 7.3 yr; range, 0.236yr), and the meanage at the time of evaluation was 12.4 years (SD, 7.7 yr; range,1.437.5 yr). We calculated a preoperative delay of 5.9 years(SD, 6.3 yr; range, 0.2528.7 yr) as the delay between the age of


DELALANDE ET AL.

onset of seizures and the hemispherotomy and a postoperativefollow-up period of 4.4 years (SD, 2.7 yr; range, 0.0311.3 yr) asthe time duration between the hemispherotomy and the age ofthe evaluation. The medical characteristics are summarized inTable 1. We reviewed all of the French (n 65) patients exceptone (Patient 61) and received the most recent data for all non-French (n 18) patients except for two (Patients 101 and 103).For these three patients, we picked up data in the medical filefrom the preceding follow-up visit.

The etiology was determined according to the underlyingpathology 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 sequel-lae (Seq; Group 4). In Group 1, 10 patients presented a largecortical dysplasia, 19 had a hemimegalencephaly, and one had

A B

I

C D

J K

SQP R

FIGURE 1. Sequences of the surgical steps for the VPH. A, a parasagittalfrontoparietal craniotomy (3 5 cm, 12 cm from the midline, one-thirdanterior and two-thirds posterior to the coronal suture) is performed withthe posterior frontal and central region exposed. BE, 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). FH, section of the floor ofthe ventricular trigone (Arrow 3) in the second step. Arrow 4, posteriorpart of the temporal horn. IN, in the third step, a laterothalamic incision



(Arrow 5) following the roof of the temporal horn of the ventricle is made.OQ, the fourth step is an anterior callosotomy (Arrow 6). RS, the fifthstep is the resection of the posterior part of the gyrus rectus (Arrow 7).TX, the sixth step involves the dissection between the resected part of the

E

L

F

M

gyrus rectus and the anterior partof the laterothalamic incision(Arrow 8).

G H

N

U V W

O

T

X

a hemimicroencephaly. In Group 4, 11 children had ischemiclesions owing to vascular insult, three had a hemiplegia hemi-convulsion epilepsy syndrome, and three had ischemic sequel-lae after meningitis. Onset of seizures, the age at hemisphero-tomy, and the age at evaluation varied significantly accordingto the etiology (P 0.0001) and was earlier in the MCD groupand later in the RE group. Preoperative delay tended to belower in the MCD group than in the other three groups(P 0.04). The duration of the postoperative follow-up period

was not statistically differentbetween the groups (Table 2).

Before hemispherotomy,all of the patients experi-enced generalized seizures,partial seizures, and/or sta-tus epilepticus, but only theMCD group exhibited in-fantile spasms (57%). The


DELALANDE ET AL.

TABLE 1. Results of the 83 patients in this studya

Age at Age atPatient onset hemispher- Age at Engel Vineland

no. (yr)/sex otomy (yr) Side Postoperative course evaluation (yr) Seizure outcome grade communication

Multilobar cortical dysplasia Group 1 (n 30)1 0.1/M 1.0 L No complication 4.5 None Ia 488 0.03/F 0.3 L No complication 1.5 None Ia 899 0.16/M 3.9 L No complication 5.9 None Ia 43

11 0.0/M 0.6 R VPS 7.2 No Sz during 1yr PO, IVa 36then daily

12 0.0/F 2.6 L No complication 11.2 None Ia 3614 0.0/F 1.7 L No complication 5.0 None Ia Not done17 4.2/M 7.5 L VPS 8.5 Only 2 Sz at 4 Ic 50

mo PO22 0.0/M 0.6 L No complication 4.0 None Ia 7025 0.2/M 7.9 R No complication 9.8 None Ia 3229 0.01/M 0.3 R VPS 5.0 None Ia 7332 0.15/F 6.8 R Scar infection + VPS 11.3 None Ia 3533 0.0/F 1,0 L SDPS 7.8 Decrease Sz (1/mo) IIIa 2737 0.04/M 3.6 R No complication 5.4 Decrease Sz intensity, IIIa 49

but still daily40 0.08/M 0.4 L No complication 2.4 None Ia 7043 0.0/F 0.7 R VPS 3.6 None Ia 7846 0.0/F 0.8 L VPS 7.3 No Sz during 8 mo PO, IIIa 47

then weekly52 0.08/M 1.2 R SDPS, Ventricul, VPS 3.3 Decrease Sz, but still IIIa 52

weekly53 0.04/M 18.2 R No complication 23.8 None Ia 2055 0.0/F 0.4 L SDPS 11.7 Two episodes Id 45

of fall (possiblySz) at 8 yr PO

56 0.05/M 6.7 L No complication 12.8 Stopped Sz after H IIc 27and no seizuresat 3 yr PO

60 0.5/F 2.0 R No complication 3.5 None Ia 7362 0.0/M 1.1 L No complication 12.2 No Sz during 8 yr PO, IIa 19

then recurrence onlyduring night (stopped bycarbazepine)

70 0.5/M 3.1 R No complication 11.8 None Ia Not done73 0.01/F 0.4 L No complication 4.8 None Ia Not done77 0.3/F 6.0 L Severe hydrocephalus at 8 d 9.2 Partial Sz IIIa Not done

PO: external derivation, VPS (1/mo to 1/wk)(3 wk PO).Still invalid

78 0.0/M 11.9 R Insipidis diabetus with meta- Not donebolic acidosis. Deceased at 3 d PO

79 0.4/F 2.0 L Reoperated at 18 mo after H. Deceased Stop Sz during 8 mo IIIa Not done2 mo later (infectious disease) PO, then weekly

80 0.2/F 14.9 R Latex allergy. Deceased at 3d PO Not done101 0.0/F 2.8 R No complication 2.8 None Ia Not done114 0.0/M 1.0 R No complication 3.5 None Ia Not done

Rasmussen encephalitis Group 2 (n 25)2 6.0/F 18.9 L No complication 29.0 None Ia 27

13 9.7/M 17.5 R No complication 19.4 None Ia 5715 2.6/F 3.3 R No complication 9.8 None Ia 8520 5.7/F 10.6 R No complication 14.3 Only 4 Sz at 4 mo PO Ic 4923 7.8/F 14.5 R No complication 16.7 None Ia 6224 2.0/F 4.2 L No complication 5.8 None Ia Not done26 1.2/M 8.7 R No complication 9.9 None Ia 4835 13.5/M 16.1 L No complication 17.1 None Ia 4745 4.3/F 5.9 R No complication 13.3 None Ia 9349 13.0/F 22.7 L No complication 29.9 Rare episodes of IIc 19

loss of consciousnesswith fall (stopped bydiazepam)



TABLE 1. continued

Age at Age atPatient onset hemispher- Age at Engel Vineland

no. (yr)/sex otomy (yr) Side Postoperative course evaluation (yr) Seizure outcome grade communication

50 3.3/M 8.9 R No complication 17.1 None Ia 3754 1.9/M 4.1 R No complication 11.4 No Sz during 4yr PO, then IIa 66

rare left clonic seizure(stopped by valproate)

58 5.5/M 9.0 L No complication 12.7 None Ia 5863 3.2/F 14.8 L No complication 24.0 Rare Sz during 3 yr Ic 19

PO, then no Sz65 10.0/F 13.6 R No complication 17.3 None Ia Not done66 4.8/F 5.8 R No complication 11.8 None Ia Not done69 10.3/F 14.0 R No complication 17.7 None Ia Not done71 4.0/M 5.7 R No complication 10.7 None Ia Not done74 3.7/M 9.6 R No complication 13.0 None Ia Not done75 2.2/M 16.8 R No complication 24.0 None Ia Not done82 6.2/M 13.4 R No complication 14.6 None Ia 6183 7.2/F 36.0 L No complication 37.5 None Ia 57

103 3.9/F 13.2 L No complication 13.5 Decrease Sz mainly IIIa Not doneduring night

115 10.5/F 14.3 L No complication 18.9 Stop Sz during 2 yr PO, then IIa 40recurrence (1/mo1/3 mo)

116 3.6/M 13.1 R No complication 21.6 Stop Sz during 1 yr PO, IIIa Not donethen recurrence mainlyduring night

Sturge-Weber syndrome Group 3 (n 10)6 0.1/M 22.7 L No complication 25.3 Fall on back at 3 mo and IIa 19

1 yr PO (possibly Sz)21 0.1/M 5.9 L No complication 8.7 None Ia 2928 0.0/F 0.4 L No complication 4.4 None Ia Not done39 0.3/F 13.9 L No complication 16.3 None Ia 2841 0.2/M 1.9 R No complication 6.3 None Ia 5442 0.2/M 1.8 L No complication 10.4 None Ia 4457 0.5/F 20.6 R No complication 24.4 None Ia 1961 0.1/M 4.4 L No complication 13.5 None Ia Not done72 0.5/M 1.0 R No complication 6.2 None Ia Not done

105 0.03/F 0.6 R No complication 4.1 Partial Sz (


DELALANDE ET AL.

FIGURE 2. Parasagittal (A), coronal (B),and axial (C) MRI scans demonstratingthe lines of disconnection of the VPH.Pre- (D) and postoperative (E) axial MRIscans of Patient 43 demonstrating righthemimegalencephaly with a large anter-ior part of the corpus callosum.

A

C

D

E

B

postoperatively. She underwent external ventricular drainage,then ventriculoperitoneal derivation, but remained in a bedrid-den state. The cerebral MRI scan, performed at 3 months post-operatively, exhibited a large area of low attenuation in thefrontoparietal region on the right side (contralateral to the sideof hemispherotomy) in keeping with an extensive cerebral

seizure frequency was daily orweekly in 82% of the children.Nine children underwent othersurgery before hemispherotomy,w h i c h w a s i n e f f i c i e n t o nseizures. These previous surger-ies included focal resection(Patients 12, 23, 53, 54, 58, 71, and 83), porencephalic cystuncapping (Patient 3), and complete callosotomy (Patient 25).

After hemispherotomy, 74% of the children (n 60) wereseizure free (Engel Class I); among these, 76.6% (n 46) werefree of antiepileptic drugs (Fig. 3). Ten children (12%) had rareseizures (Engel Class II). Eleven children (14%) continued tohave seizures and were classified as Engel Class III (n 9) orEngel Class IV (n 2). The results varied according to the eti-ology, but this variation was not statistically significant (Fig. 4).In terms of seizure outcome, the best results were achieved inpatients with Rasmussen encephalitis and Sturge-Weber dis-ease with 92 and 100% classified in Engel Class I or II, respec-tively. These percentages were 88 and 75%, respectively, forischemic-vascular sequellae and cerebral malformation. We didnot find any changes in the long-term outcome according to theseizure frequency outcome. There was the same proportion ofpatients classified as Engel Class I or II regardless of the dura-tion 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 hydro-cephalus, for which ventriculocisternostomy was performed intwo (Patients 34 and 18), ventriculoperitoneal shunt in seven(Patients 11, 17, 29, 32, 43, 46, and 77), a subdural peritonealshunt in three (Patients 19, 33, and 55), and all three proce-dures in one child (Patient 52). One of the children who hadventriculoperitoneal shunt placement developed a local woundinfection associated with meningitis (Patient 32). Another child(Patient 77) developed severe intracranial hypertension 8 days



infarction. Postoperatively, three children died (3.6%), two ofthem within the first week after hemispherotomy. An 11-year-old boy (Patient 78) developed severe diabetes insipidus withrefractory hypernatremia and died on the fourth postoperativeday. A 15-year-old girl (Patient 80) died 3 days postoperativelyowing to a latex allergy (diapers). The third child, a 2-year-oldgirl (Patient 79) with hemimegalencephaly, was reoperated (bythe same neurosurgeon) 18 months after the first hemisphero-tomy for recurrent seizures. This was the only child in ourseries who underwent a second-look surgery for persistingor recurring seizures. As the hemispherotomy was intraopera-tively proved to be complete in this case, it was not necessaryto perform any other surgical procedure, and the girl wasuneventfully discharged at home 10 days postoperatively. Shewas, however, rehospitalized 1 month later in a context ofinfectious disease (fever, otitis, gastroenteritis) and clinical dete-rioration rapidly occurred, requiring intensive care 4 days later.She died 8 days after the onset of her symptoms. The familyrefused 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 whowalked alone before surgery. Among the children who did notacquire independent walk (n 12), seven were in the youngestpatient group (< 4 yr at evaluation). Four children had a severemental deficiency associated with multiple cortical dysplasiaand one had Rasmussen encephalitis (Patient 63), but lost theability to walk several years before surgery. When hemispher-otomy was performed early in life, the ability to walk wasacquired between the age of 19 months and 4 years 4 months.The degree of spasticity of the hemiparetic limbs was differentin the RE and the Seq groups than in the other two groups.Whereas the wrist was retracted in the majority of the first twogroups (58 and 64%, respectively), the joints showed only aslight retraction or were suppler in most patients in the lattertwo groups (85%). When testing the ability of the hemipareticupper limb, 61% were able to put the hand on the head and30% on the back; none of the children was operated on for this

FIGURE 3. Bar graph showing the outcome of the whole population withrespect 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 classifica-tion) according to the duration of the follow-up period.

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) 0.2 (0.76) 5.9 (3.5) 0.3 (0.2) 1.0 (1.8)


DELALANDE ET AL.

guage in 91 and 82%, respectively, but a worsening in motorfunction in 26%, particularly concerning the hand function onthe hemiparetic side.

Vineland Adaptive Behavior ScaleThese results concern 58 out of 65 French patients. Seven

patients were not included, either because the families were notreliable (Patients 7, 14, and 28) or the patients could not bereviewed (Patients 61, 78, and 79). We did not analyze theresults of Patient 83 because she had lobar resection 10 yearsbefore hemispherotomy (Fig. 6; Tables 3 and 4).

The mean Vineland Composite Score was low (43 15) com-pared with the norm (100 15), but with heterogeneity accord-ing to the domain. The children achieved higher scores in social-ization (57 19) compared with communication (45 20) ordaily living skills (41 21) (P 0.0001). For the socializationand communication domains, there was a wide range of scores,ranging from 19 to 89. The lowest score was observed for motorskills (39 14). For instance, no child was able to ride a bicy-cle without training wheels or catch a small ball from a distanceof 10 feet.

According to the side, children with right hemispherotomyshowed a better communication score than children with lefthemispherotomy. As a function of etiology, the Rasmussengroup had the best results in all four domains (Table 3).

Preoperative delay was negatively and significantly associ-ated to all the Vineland scores, except for motor skills. Thelonger the duration of epilepsy, the lower the scores (Fig. 6;Table 4). This relation was similar in right and left hemisphero-tomy, 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 com-munication score of more than 50; of them, eight (91%) had apreoperative delay less than 2 years. Inversely, in the RE andSeq groups (n 30), 18 had a Vineland communication scoreless than 50; of them, 14 (78%) had a preoperative delay ofmore than 4 years.

spasticity. Ten children (14%) acquired voluntary prehension ofthe hand on the hemiparetic side and were able to grab a smallobject (e.g., a pencil). Nevertheless, none of them had fine pre-hension (thumb-index pincer) or the ability to put a pearl in abottle. Thirty-six percent of the children were able to hold asmall 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 for 9, 8, and 7%, respec-tively, of the children postoperatively.

For sixty-nine patients, we obtained sufficient data concern-ing school placement and re-education schedules. Consideringtheir routine daily life, all of them had several types of re-educations each week. According to age, thirty-three children(56%) between 3 and 20 years of age (n 59) were able to goto school. Among them, 13 were in normal school (nine innursery school and four in elementary school) and 20 were inspecialized schools. Twenty-six (44%) were in an institution.After the age of 20 (n 10), all of them were in an institutionexcept one who was in protected employment. Globally, whenwe asked the parents how they evaluated the outcome of thechild, they reported an improvement in behavior and lan-

FIGURE 6. Scatterplot showing the Vineland communication score versuspreoperative delay.

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)

SideRight (SD) 24 52 (22)b 43 (21) 59 (20) 53 (21) 47 (18)Left (SD) 34 41 (19)b 40 (22) 55 (20) 46 (20) 41 (16)

EtiologyG1: MCD (SD) 21 49 (20) 40 (20) 58 (17) 40 (14)c 43 (15)G2: RE (SD) 15 51 (21) 53 (24) 62 (19) 64 (23)c 51 (18)G3: SW (SD) 6 32 (14) 31 (14) 50 (26) 42 (18)c 35 (15)G4: Seq (SD) 16 41 (20) 36 (19) 54 (23) 53 (20)c 40 (17)

a SD, standard deviation; MCD, multilobar cortical dysplasia; RE, Rasmussen encephalitis; SW, Sturge-Weber syndrome; Seq, ischemic-vascular sequelae.b P 0.04.c P 0.004.



described the VPH. We assume that with this verticalapproach, a complete disconnection of the affected hemispherecan be achieved and that it offers the advantage of a clearintraoperative assessment of completeness of the hemisphero-tomy and preservation of an intact vessel supply. Moreover,the incision is limited to the minimum necessary cut to reachto a functional exclusion of the entire hemisphere by respect-ing the same section as in anatomic hemispherectomy. Thistechnique ensures that the anatomic landmarks take intoaccount the surgical concept of a central core of the hemi-sphere proposed by Wen et al. (31). The central core of a hemi-sphere consists of the extreme, external, and internal capsules,claustrum, lentiform and caudate nuclei, and thalamus.Externally, this core is covered by the insula and surroundedby the fornix, choroid plexus, and lateral ventricle. Wen et al.(31) proposed key anatomic landmarks for hemispherotomytechniques that can be used to disconnect the hemisphere fromits lateral surface around the insula, through the lateral ventri-cle, and toward the midline. The parasagittal approach realizesthe incision around the central core and makes it easier toassess the completeness of the disconnection. In our popula-

TABLE 4. Vineland statistical analysisa

Medical characteristics Communication Daily living skills Socialization Motor skills Global score

Total (n 58)

Age onset of seizurePreoperative delayPostoperative follow-up

0.060.61e

0.37d

0.200.47d

0.34c

0.040.44d

0.18

0.39c

0.100.23

0.160.51e

0.31b

Side

Right side(n 24)

Age at onset of seizurePreoperative delayPostoperative follow-up

0.310.65d

0.02

0.390.44b

0.14

0.260.52b

0.08

0.58c

0.070.16

0.370.54c

0.06

Left side(n 34)


0.170.62d

0.48c

0.080.45c

0.40b

0.110.37b

0.21

0.260.12

0.29

0.0050.47c

0.38b

Etiology

Group 1 (MCD)(n 21)


0.130.59c

0.60c

0.120.53b

0.58c

0.060.61c

0.33

0.020.350.28

0.070.59b

0.54b

Group 2 (RE)(n 15)


0.290.70c

0.26

0.270.60b

0.46

0.52b

0.57b

0.003

0.160.430.36

0.100.78d

0.35

Group 3 (SW)(n 6)


0.200.93c

0.61

0.210.760.51

0.310.600.03

0.670.090.06

0.030.87b

0.49

Group 4 (Seq)(n 16)


0.010.62b

0.43

0.060.410.48

0.150.340.36

0.160.29

0.25

0.0030.460.045

a MCD, multilobar cortical dysplasia; RE, Rasmussen encephalitis; SW, d P < 0.001.Sturge-Weber syndrome; Seq, ischemic-vascular sequelae. e P < 0.0001.b P < 0.05.c P < 0.01.

The age at the onset of seizures was not significantly relatedto the Vineland scores, except for motor skills. The later theonset of epilepsy, the better the motor skills score (P 0.01).

In the total population, the postoperative follow-up periodwas negatively correlated with the composite communicationand daily living skills scores. The longer the follow-up period,the lower the scores. However, this relation was dependent onthe side, being significant only for patients undergoing lefthemispherotomy, and on the etiological group, being signifi-cant only in the MCD group. In this group, the discrepancybetween chronological age and mental age, as evaluated by theVineland scale, increased with the duration of the postopera-tive follow-up period.

DISCUSSION

This is a large population of children with epilepsy treatedby hemispheric disconnection with the same surgical approachand conducted by the same surgeon. Moreover, we were ableto obtain recent data for 94% of the operated patients with animportant long-term follow-up period. In this article, we

but we have never seen any brain swelling that should happenin such a situation.

Concerning the efficacy on seizures, 74% of the patients wereseizure-free with no seizure recurrence in a long-term follow-up period and no necessity to reoperate. Among the surgicaltechniques for epilepsy, hemispherectomy and hemisphero-tomy carry the best results in terms of seizure freedom, whichpermits, after a sufficient follow-up period, the reduction andtermination of antiepileptic drug treatment in a high percent-age of patients. In our population, we successfully stoppedantiepileptic drug treatment in 77% of the group classified asEngel Class I.

The factors affecting seizure control are not completely elu-cidated, but several authors have suggested that differences inetiology, as well as the technique of hemispheric disconnec-tion, explains a portion of this variability. Globally, with lateralhemispherotomy, the rate of patients becoming seizure-freehas been indicated to be between 68 and 88% (14, 28). For themodified lateral hemispherotomy, there was a seizure-free out-come in the first 2 postoperative years of 82.7 and 66.7% inpatients with cortical dysplasia and Rasmussen encephalitis,respectively. However, the score decreased at 5 years postop-eratively to 60.5 and 62.5% (14). The largest study on seizureoutcome was reported by Holthausen et al. (11) in a popula-tion of 333 hemispherectomies from 13 different centers with aminimum follow-up period of 6 months. The percentage ofseizure-free patients was better in the hemispherotomy tech-niques (85.7% were seizure-free) and in the group of patientsincluding Rasmussen, Sturge-Weber, and vascular insults(94.6% became seizure-free). The other group of patients,including cerebral dysplasia and other etiologies (sequellae ofinfections, postmeningitis, postencephalitis) became seizure-free in 68% of the cases.

In our population, Groups 2 (RE), 3 (SW), and 4 (Seq) alsopresented the best result on seizure outcome with 80, 80, and78%, respectively, being graded as Engel Class I. It should bementioned that patients classified in Group 4 concerned vari-ous origins of ischemic lesions, among them ischemic perinatallesions, hemorrhage, postinfectious, and hemiconvulsion hemi-plegia epilepsy syndrome. Some of these patients could be clas-sified as other or miscellaneous in some studies, which mayexplain why we do not have as good a result as in the twoother groups. Moreover, because the resection of the cortex wasstandardized in the frontal area according to the verticalapproach, but not primarily directed to the anatomopatholog-ical diagnosis, it was not possible to make extensive patholog-ical examination for this group.

Finally, the MCD group had the least favorable outcome,with only 66% of patients becoming seizure-free. This groupalso had the highest rate of postoperative shunting (33%). Inthis group of etiology, there is some difficulty proving that theopposite hemisphere is not affected because there are bilateralinterictal EEG abnormalities, and sometimes bilateral neu-ropathological changes following autopsy (13, 23).

Considering the group of children who had undergone sur-gery before hemispherotomy, seven had focal resection, one

tion, only one child (Patient 79) underwent reoperation forseizure recurrence, despite no signs of incomplete disconnec-tion on the postoperative MRI scans. The hemispherotomywas intraoperatively proven to be complete and no other sur-gical procedure was performed.

Compared with the three techniques of lateral hemisphero-tomy (24, 25, 27), the interruption of the associative and com-missural neuronal fibers is complete because the incision isthe same as in the anatomic hemispherectomy (18). It allows acomplete disconnection, including the insular cortex, whenthe lateral approaches require its removal. Furthermore, allthe incisions are in a vertical plane. Therefore, it seems morelogical to achieve surgery through a vertical route. The longdistance between the surface and the deep incisions are not adisadvantage with modern microscopes and a relatively thinultrasonic aspirator. Moreover, our technique allows theutmost degree of vessel preservation within the disconnectedhemisphere (middle cerebral artery and main venous drainagesystems), reducing the risk of brain swelling secondary toischemia (6). In the modified lateral hemispherotomydescribed by Cook et al. (3), the principle of this techniquewas to create a working space around the ventricular systemby removing most of the thalamus, basal ganglia, and caudatenucleus associated with early ligation of the MCA. This tech-nique was compared with anatomic and functional hemi-spherectomy and resulted in fewer perioperative risks and ashorter hospital stay than the two older techniques.Postoperative mortality and morbidity was reported in detailby Cook et al. (3) and Jonas et al. (14), who compared theadvantages and disadvantages associated with each hemi-spherectomy technique (anatomic, functional, and modifiedlateral hemispherectomy). They demonstrated that modifiedlateral hemispherotomy seemed to have the lowest complica-tion rate (35, 34, and 11%, respectively) and a reduced neces-sity of shunt (78, 9.4, and 22%, respectively), even if the mod-ified lateral hemispherotomy technique suggests a highershunt rate than that with the functional hemispherectomytechnique. In our population treated by VPH, the necessity forshunt placement was 16% (the complication rate for the otherswas 6%), suggesting that this technique is successful inimproving the safety of hemispherotomy technique.Compared with the other disconnection techniques, VPH canbe easier to perform in the group of patients with hemisphericcortical cerebral dysgenesis associated with catastrophicepilepsy. These children exhibit seizures, beginning in thefirst weeks of life, which are usually uncontrolled by theantiepileptic drugs, and evolving in refractory epilepsy with apoor intellectual outcome. It seems, therefore, important topropose an early, safe, and reliable hemispheric disconnection.We have pointed out that shunt placement was necessary in 13children (16%), among them were 10 in the MCD group (33%of Group 1) and three in the Seq group (17% of Group 4), butnone in the two other groups. It is difficult to understand whyhydrocephaly is so common in the hemimegalencephaly pop-ulation. The intraoperative evidence of an abnormal deepvenous drainage that is interrupted could be an explanation,


DELALANDE ET AL.

hemispheric syndrome has been precisely documented.Prospective studies should be conducted to confirm these resultson a larger population and with longer outcome duration.

REFERENCES

1. Adams CB: Hemispherectomy: A modification. J Neurol NeurosurgPsychiatry 46:617619, 1983.

2. Carson BS, Javedan SP, Freeman JM, Vining EP, Zuckerberg A, Lauer JA,Guarnieri M: Hemispherectomy: A hemidecortication approach of 52 cases. JNeurosurg 84:903911, 1996.

3. Cook SW, Nguyen ST, Hu B, Yudovin S, Shields WD, Vinters HV, van deWiele BM, Harrison RE, Mathern GW: Cerebral hemispherectomy in pediatricpatients with epilepsy: Comparison of the three techniques by pathologicalsubstrate in 115 patients. J Neurosurg 100 [Suppl 2]:125141, 2004.

4. Cosgrove GR, Villemure JG: Cerebral hemicorticectomy for epilepsy.J Neurosurg 79:473474, 1993.

5. Dandy WE: Removal of right cerebral hemisphere for certain tumors withhemiplegia: Preliminary report. JAMA 90:823825, 1928.

6. Daniel RT, Villemure JG: Hemispherotomy Techniques. J Neurosurg98:438439, 2003.

7. Delalande O, Pinard JM, Basdevant C, Gauthe M, Plouin P, Dulac O:Hemispherotomy: A new procedure for central disconnection. Epilepsia 33[Suppl 3]:99100, 1992.

8. Delalande O, Fohlen, Jalin, Pinard JM: From hemispherectomy to hemispher-otomy, in Lders HO, Comair YG (eds): Epilepsy Surgery. Philadelphia,Lippincott Williams & Wilkins, 2001, ed 2, pp 741746.

9. Engel J: Outcome with respect to epileptic seizures, in Engel J (ed): SurgicalTreatment of the Epilepsies. New York, Raven Press, 1987, pp 553571.

10. Holthausen H, Pieper T: Complications of hemispherectomy, in Lders HO,Comair YG (eds): Epilepsy Surgery. Philadelphia, Lippincott Williams &Wilkins, 2001, ed 2, pp 879883.

11. Holthausen H, May TW, Adams TB, Andermann F, Comair Y, Delalande O,Duchowny M, Freeman JM, Hoffman HJ, May P, Oppel F, Oxbury JM,Peacock WJ, Polkey C, Resnick T, Schramm J, Shewmon DA, Tuxhorn I,Vigevano F, Vil lemure JG, Wyllie E, Zaiwalla Z: Seizures post-hemispherectomy, in Tuxhorn I, Holthausen H, Boenig H (eds): PaediatricEpilepsy Syndromes and their Surgical Treatment. London, John Libbey, 1997,pp 749773.

12. Ignelzi RL, Bucy PC: Cerebral hemidecortication in the treatment of infantilecerebral hemiatrophy. J Nerv Ment Dis 147:1430, 1968.

13. Jahan R, Mischel PS, Curran JG, Peacock WJ, Shields DW, Vinters HV:Bilateral neuropathologic changes in a child with hemimegalencephaly.Pediatr Neurol 17:344349, 1997.

14. Jonas R, Nguyen S, Hu B, Asarnow RF, LoPresti C, Curtiss S, de Bode S,Yudovin S, Shields WD, Vinters HV, Mathern GW: Cerebral hemispherec-tomy: Hospital course, seizure, developmental, language, and motor out-comes. Neurology 62:17121721, 2004.

15. Krynauw RA: Infantile hemiplegia treated by removing one cerebral hemi-sphere. J Neurol Neurosurg Psychiatry 13:243267, 1950.

16. Laine E, Pruvot P, Osson D: Ultimate results of hemispherectomy in cases ofinfantile cerebral hemiatrophy productive of epilepsy [in French]. Neuro-chirurgie 10:507522, 1964.

17. Lhermitte J: Ultimate results of hemispherectomy in cases of infantile cere-bral hemiatrophy productive of epilepsy [in French]. Encphale 23:314323,1928.

18. Morino M, Shimizu H, Ohata K, Tanaka K, Hara M: Anatomical analysis ofdifferent hemispherotomy procedures based on dissection of cadavericbrains. J Neurosurg 97:423431, 2002.

19. Oppenheimer DR, Griffith HB: Persistant intracranial bleeding as a complica-tion of hemispherectomy. J Neurol Neurosurg Psychiatry 29:229240, 1966.

20. Piastra M, Pietrini D, Caresta E, Chiaretti A, Viola L, Cota F, Pusateri A,Polidori G, Di Rocco C: Hemispherectomy procedures in children:Haematological issues. Childs Nerv Syst 20:453458, 2004.

21. Prayson RA, Bingaman W, Frater JL, Wyllie E: Histopathologic findings in 37cases of functional hemispherectomy. Ann Diagn Pathol 3:205212, 1999.

had callosotomy, and one had surgery for a porencephalic cyst.Among the seven children undergoing focal resection, five pre-sented with a Rasmussen encephalitis (20% of the RE group)and hemispherotomy was avoided to preserve hand motorfunction because the children were not yet hemiplegics.However, focal surgery was not efficient because these chil-dren remained with frequent epileptic seizures. Therefore, itseemed that the indication of hemispherotomy could be consid-ered in patients with Rasmussen syndrome, even without acomplete hemiparesis, but with progressive neuropsychologi-cal alterations and/or frequent status epilepticus (29).

According to the global long-term evolution assessed by theVineland scale, we found a strong correlation between the pre-operative delay and global long-term outcome according to thethree domains of communication, socialization, and daily lifeability. The shorter the duration of the seizures, the better thepostoperative status of the child in all four etiological groups.These results corroborated with those of Jonas et al. (14), whoused the Vineland scale in the postoperative course in a popu-lation of 52 children treated by hemispherectomy or hemi-spherotomy. They suspected that patients with seizure durationof 3 years or less had a better outcome. In our series, we con-firmed the significance of performing surgery early after theonset of seizures and proposed to decrease the preoperativedelay to 2 years or less, especially in children with MCD andSW who have seizure onset early in life.

Although these children made significant progress in thedevelopment, we found a negative correlation between thepostoperative follow-up duration and the Vineland score, butonly in the group of children in whom hemispherotomy wasperformed on the left side. These children tended to have aless impressive outcome because the discrepancy betweenchronological age and mental age, as evaluated by theVineland scale, increased with the duration of the postopera-tive follow-up period. To our knowledge, we are the first toreport on the effect of the long-term follow-up periods onglobal development. We may hypothesize that, in this group ofchildren, the right hemisphere tends to be unable to developthe same abilities as the left side in the domain evaluated bythe Vineland scale.

Regarding correlation with global outcome, we shouldacknowledge that there may be other confounding factors (e.g.,preoperative cognitive development, antiepileptic drug, delaycoming to surgical attention), which could interfere with prog-nosis, independent of when the surgery is performed. Furtherprospective studies are needed.

CONCLUSION

VPH is a surgical procedure for hemispheric disconnectionthat, with a low rate of complications, seems to be at least as safeas the other common procedures. Moreover, this procedureallows the achievement of good control for seizures, with 74% ofthe patients becoming seizure-free. This procedure must be pro-posed as soon as possible after the onset of epilepsy when a



22. Rasmussen T: Hemispherectomy for seizures revisited. Can J Neurol Sci10:7178, 1983.

23. Robain O, Floquet C, Heldt N, Rozenberg F: Hemimegalencephaly: A clin-icopathological study of four cases. Neuropathol Appl Neurobiol14:125135, 1988.

24. Schramm J, Kral T, Clusmann H: Transsylvian keyhole functional hemi-spherectomy. Neurosurgery 49:891901, 2001.

25. Schramm J, Behrens E, Entzian W: Hemispherical deafferentation: An alterna-tive to functional hemispherectomy. Neurosurgery 36:509516, 1995.

26. Shimizu H, Maehara T: Modification of peri-insular hemispherotomy andsurgical results. Neurosurgery 47:367373, 2000.

27. Sparrow SS, Balla DA, Cicchetti DV: Vineland Adaptative Behavior Scales(VABS). Circle Pines, American Guidance Service, 1984.

28. Villemure JG, Mascott CR: Peri-insular hemispherotomy: Surgical principlesand anatomy. Neurosurgery 37:975981, 1995.

29. Villemure JG, Vernet O Delalande O: Hemispheric disconnection:Callosotomy and Hemispherotomy, in Cohadon F (ed): Advances and TechnicalStandards in Neurosurgery. Vienna, Springer-Verlag, 2000, vol 26, pp 2578.

30. Vining EP, Freeman JM, Pillas DJ, Uematsu S, Carson BS, Brandt J, BoatmanD, Pulsifer MB, Zuckerberg A: Why would you remove half a brain? The out-come of 58 children after hemispherectomyThe Johns Hopkins Experience:19681996. Pediatrics 100:163171, 1997.

31. Wen HT, Rhoton AL Jr, Marino R Jr: Anatomical landmarks for hemisphero-tomy and their clinical application. J Neurosurg 101:747755, 2004.

32. Wilson PJ: Cerebral hemispherectomy for infantile hemiplegia. A report of 50cases. Brain 93:147180, 1970.

33. Winston KR, Welch K, Adler JR, Erba G: Cerebral hemicorticectomy forepilepsy. J Neurosurg 77:889895, 1992.

AcknowledgmentsThis work was supported by Pfizer Laboratory (MS, MN). We thank Francine

Lussier, M.D., Ph.D. (Montreal, Canada) for translation into the French versionof 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.

COMMENTS

The authors provide a retrospective study on a series of 83 casesusing the vertical parasagittal hemispherotomy technique. Thistechnique provides seizure outcome and complication rates comparableto other contemporary series of hemispherotomy and functional hemi-spherectomy. However, the shunt rate is somewhat higher (> 16%).After the initial publication (1), this is the first article in which the readercan easily follow the description of the surgical technique itself.

Devin BinderJohannes SchrammBonn, Germany

1. Delalande O, Pinard JM, Basdevant C: Hemispherotomy: A new procedure forcentral disconnection. Epilepsia 33 [Suppl 3]:99100, 1992.

These authors have much experience and success with this particu-lar hemispheric disconnection technique. As I have learned fromthe patients in this study, the important factor is getting the hemi-sphere disconnected with the least amount of trauma to the patient aspossible. The authors report their wonderful outcomes in terms of bothseizure-free and complication rates. It is important for the epilepsysurgeon to appreciate the individuality of each patient who is a candi-date for hemispheric disconnection and to apply the most suitable tech-nique for that patient. For example, minimally invasive techniquesmay be more suitable for patients with perinatal stroke, whereas amodified functional or anatomic technique may be better suited topatients with hemimegalencephaly. Regardless, the surgeon must becomfortable with the technique performed and this requires adequatetraining and ongoing experience in the surgical care of these patients.

William E. BingamanCleveland, Ohio

DELALANDE ET AL.


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