Child's Nerv Syst (1993) 9:72-80

IIINS �9 Springer-Verlag 1993

Surgical indication in children with congenital hemiparesis C. Di Rocco 1, M. Caldarelli 1, E Guzzetta 2, G. Torrioli 2

1 Institute of Neurosurgery, Section of Pediatric Neurosurgery, Catholic University Medical School, Largo A. Gemelli, 8, 1-00168 Rome, Italy 2 Institute of Neurology, Section of Child Neurology, Catholic University Medical School, Rome, Italy

Received: 10 June 1992

Abstract. Nine children with perinatal occlusion of the middle cerebral artery, resulting in unilateral enlargement of one lateral cerebral ventricle associated with cortical a t rophy and subcortical cavity formation, were operated on because of intractable epilepsy. All subjects exhibited mild to severe hemiparesis, localized in the right side of the body in six instances and in the left side in three cases. All but one patient presented with some degree of psycho- moto r retardation. The surgical t reatment consisted of the removal of the atrophic cerebral cortex. One child died after surgery because of disseminated intravascular coagulation. All the remaining eight children benefited from the operation, with a decrease in the hypertonia of the affected limbs and an improvement in dexterity and gait as well as in intellectual performance. Five patients could be considered seizure-free following the surgical treatment, and the remaining three experienced a signifi- cant reduction in the frequency of the seizures.

Key words: Congenital hemiparesis - MCA occlusion - Epilepsy - Cort icectomy

subjects with congenital hemiparesis. The first was char- acterized by the enlargement of one lateral cerebral ven- tricle associated with atrophy, and possibly with cavity formation, in the territory of distribution of the middle cerebral artery (cortical/subcortical atrophy). The second pat tern was distinguished by the association of a unilater- al ventricular enlargement with paraventr icular lesions (paraventricular a t rophy or subependymal cavity forma- tion).

While the second pat tern of CT abnormalities ap- peared to bear a better prognosis, as generally the affected children did not suffer from severe mental retardation or seizure disorder, subjects with cortical/subcortical atro- phy on the CT scan frequently showed severe hemipare- sis, intellectual impairment, and epilepsy [3, 24].

In the present report we describe nine children with congenital hemiparesis and intractable epilepsy, associat- ed with cortical/subcortical a t rophy in the territory of distribution of the middle cerebral artery, diagnosed at the CT examination. All of these children underwent sur- gical removal of the atrophic cerebral cortex.

Introduction

In the late 1970s and early 1980s several studies aimed at providing new insight into the causes, the mechanisms, and the time of onset of cerebral lesions responsible for various congenital mo to r handicaps, were carried out us- ing ul t rasonography and computed tomography (CT) scans [3, 6, 12, 14, 19, 21-25 , 29-31]. The incidence of abnormal scans was extremely high among the popula- tion with congenital cerebral palsy, with figures ranging around 6 5 - 9 0 % of cases; the highest percentage of ab- normal scans was found in patients with spastic hemi- paresis [23-25, 29, 30].

Two main morphological patterns of abnormalit ies were detected at the CT examinat ion in the group of

Correspondence to: C. Di Rocco

Patients and methods

Nine children, seven males and two females, ranging between 5 months and 12 years of age, were included in the present study (Table 1). All the children were born at term; however, a dystocic delivery was reported in four cases. Perinatal asphyxia was de- scribed in five subjects. In all cases, a motor impairment was noticed by parents during the first months of life, because of either reduced active motility of a limb or asymmetry in the gesture of prehension. The motor deficit was localized in the right side of the body in six instances and in the left in the remaining three. At diagnosis the hemiparesis was severe in two cases, moderate in four and mild in three. Epilepsy, in the form of either simple partial motor seizures or partial seizures evolving to generalized tonic-clonic convulsions, accompanied the motor deficit in nearly half of the cases.

At diagnosis, all children were affected by epilepsy; the semiolo- gy of the seizures had become more complex, with various semio- logic patterns in the different patients (Table 1). In all cases, the seizures appeared to to be resistant to pharmacological treatment. All but one patient exhibited some degree of psychomotor retarda-

Table 1. Clinical and laboratory findings. L, Left; R, right; ACA, anterior cerebral artery; MCA, middle cerebral artery

Patient Sex Age at Delivery First Clinical Neuroradiological EEG pattern no. diagnosis symptoms manifestations investigations

1 M 5 months Cesarean section R-sided Epilepsy (partial simple) CT scan: L fron- L frontal spike- (fetopelvic dis- seizures resistant to therapy; totemporal hypodense wave focus proportion) mild R spastic hemi- lesion

paresis Angio: hypoplastic L MCA with absence of one main branch

M 3 months Skull X-rays: cranial asymmetry (R > L) CT scan: L fron- totemporal hypodense (cystic) lesion Angio: hypoplastic L MCA

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2 Eutocic. Threat- R-sided hemi- ened abortion at paresis 2nd & 6th months of preg- nancy

3 M 8 months Dystocic. Peri- Epilepsy and natal asphyxia R-sided hemi-

paresis

4 M 2-3 months Dystocic. Peri- L-sided hemi- natal asphyxia paresis

5 F 4 -5 months Cesarean section. R-sided hemi- Perinatal as- paresis phyxia

6 F 4 months Dystocic (pro- R-sided hemi- longed labor), paresis Perinatal as- phyxia

7 M 4 - 5 months

8 M 4-5 months

9 M 10 months

Cesarean deliv- R-sides hemi- ery. Perinatal as- paresis. Epi- phyxia lepsy

Dystocic (re- L-sided hemi- topelvic dispro- paresis. Epi- portion) lepsy

Cesarean deliv- Epilepsy, L- cry (fetopelvic sided hemi- disproportion) paresis

Moderate R spastic hemiparesis (arm > leg); epilepsy resistant to therapy (partial simple - partial complex), severe developmental delay

L frontotempo- ral slow wave fo- cus with spike activity. Hyps- arrhythmia

Epilepsy resistant to CT scan: L temporo- Hypsarrhythmia therapy (partial complex insular hypodense seizures - infantile (cystic) lesion spasms); severe spastic Angio: hypoplastic R hemiparesis temporal branches of

L MCA

L-sided spastic hemi- CT scan: R tem- L temporocen- paresis (arm > leg); de- poroparietal hypo- tral epileptic fo- velopmental delay dense lesion cus (slow waves seizures (partial corn- Angio: hypertrophic and spikes) plex) resistant to ther- R ACA; hypoplastic apy R MCA and R trans-

verse sinus

Epilepsy resistant to CT scan: L (fronto)- L-sided slow therapy (partial complex parietal hypodense waves and spikes seizures); moderate R (cystic) lesion focus spastic hemiparesis; mild developmental delay

Epilepsy resistant to CT scan: L tem- L temporal therapy (partial complex poroparietal hypo- spike-wave focus seizures); R spastic dense (cystic) lesion hemiparesis; mild devel- opmental delay

Epilepsy resistant to CT scan: L fron- L temporal therapy; severe spastic R totemporal hypodense spike-wave focus hemiparesis; develop- lesion mental delay; language absent

Epilepsy resistant to CT scan: R temporal R temporocen- therapy, with changing hypodense (polycys- tral epileptic fo- semiology (oculogyric- tic) lesion cus (slow waves infantile spasms) L MRI: R temporal and spikes) hemiparesis; mild devel- polycystic lesion opmental delay; squint

Epilepsy resistant to CT scan: R temporal R temporocen- therapy (partial simple hypodense (cystic) le- tral epileptic fo- seizures); moderate de- sion cus (slow waves vetopmental delay; L- Angio: hypoplastic R and spikes sided spastic hemiparesis MCA (with absence

of one main branch)

tion, ranging from moderate (five cases) to severe (three cases). In all subjects, the motor deficit was prevalent in an upper limb. One child did not develop speech.

All the patients were examined by CT scan and/or magnetic resonance imaging (MRI). In all instances, "cystic" lesions in the

territory of distribution of the sylvian artery were noticed. The CT hypodense lesions involved parts of the frontal, parietal, and tem- poral cortex to a different extent (Fig. 1) and extended into the underlying white matter, reaching the lateral ventricle in some sub- jects. However, the ependymal lining appeared to be preserved in all

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Fig. 1 A-D. Four-month-old girl presenting with congenital hemiparesis and seizure disor- der. Axial computed tomographic (CT; A) and magnetic resonance (MR; B) scans demonstrate an area of cortical/subcortical atrophy involving the territory of distribution of the left middle cerebral artery. Note the atrophic changes of the whole left hemisphere and the reduction in size of the corresponding hemicranium. Sagittal MR scans (C, D) give a better definition of the relation of the brain cavitation with the sylvian fissure and the left temporal horn

Fig. 2A-D. Three-month-old boy with congenital hemiparesis and intractable seizures. Right carotid angiography (A) reveals the absence of the main branches of the right middle cerebral artery. CT scan (B) shows a right frontoparietal "cystic" lesion separated from the dilated ipsilateral ventricle by a thin septum. At operation (C) the atrophic cerebral cor- tex appears clearly demarcated from the surrounding normal one left untouched by the surgical procedure which is lim- ited to the removal of the congenital le- sion (D)

Table 2. Surgical findings and outcomes

Patient Age at Operation Postoperative course Late results Duration of no. operation follow-up

1 6 months Removal of dystrophic L Immediate disappearance Good psychomotor develop- 96 months temporoparietal cortex of seizures ment; no motor deficit. (and of the temporal pole) Seizure-free (with therapy)

Removal of the L hypo- Further improvement in psy- plastic fronto-temporo- chomotor development and parietal cortex (microgyria) R hemiparesis. Sporadic

seizures (with therapy)

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2 15months Improvement in psychomo- tor development and seizure control

3 15 months Removal of the dysplastic Death in the early postop- L temporal cortex erative course

4 27 month Removal of R temporal Improvement in spastic and parietal hypoplastic hemiparesis and in school cortex (with preservation performance of the Labb6 vein)

5 40 months Removal of the hypoplastic Improvement in spastic L parietal cortex hemiparesis

6 48 months Removal of the L hypo- plastic temporoparietal cortex (and of the temporal pole)

7 60 months Removal of the L hypo- plastic frontal and tempo- ral cortex

8 70 months Removal of dystrophic R temporal cortex

9 12 years Removal of the dystrophic R temporal cortex

Improvement in spastic hemiparesis and in psycho- motor development. No seizures

Reduction of seizure fre- quency. No change in psy- chomotor development

Disappearance of seizures. Improvement in spastic hemiparesis and squint. Better school performance

Disappearance of seizures

Satisfactory improvement in psychomotor development and behavior. No seizures (with therapy)

Good psychomotor develop- ment. Seizure-free (with ther- apy)

Further improvement in psy- chomotor development. Seizure-free (with therapy)

Seizures reduced in frequen- cy (with therapy)

Very good psychomotor de- velopment. Further improve- ment in spastic hemiparesis. No seizures (without thera- PY)

Improvement in spastic hemiparesis (persistent dis- ability in left hand) and psy- chomotor development. Seizures reduced in frequen- cy (with therapy)

96 months

24 months

6 months

24 months

19months

24months

60 months

instances. In four cases the entire affected cerebral hemisphere ap- peared to be reduced because of diffuse atrophy.

Cerebral angiography was performed in four patients; the char- acteristic pathological findings of the condition were lack of or severe hypoplasia of the principal branches of the sylvian artery (Fig. 2), a diminished capillary blush in the territory of the middle cerebral artery, and hypoplasia of the homolateral transverse sinus.

The EEG examination demonstrated focal epileptic activity (spike/wave focus) in the affected cerebral hemisphere in seven cases; the remaining two children showed a hypsarrhythm pattern.

All the patients underwent surgical treatment. The postopera- tive follow-up period varied from 1 to 8 years (mean follow-up 3 years).

Results

Surgical findings

All patients (Table 2) underwent surgical removal of the a t rophic cerebral cortex: the surgical excision was made along the border of the sur rounding normal cerebral cor- tex. In all the patients this border was easily recognizable,

bo th at the inspection and dur ing the surgical procedure of cortical excision, as the affected cerebral cortex ap- peared obviously thinner, with flattened sulci and gyri which were hypovascular ized and paler than normal . In some patients the affected cortex had an obvious micro- gyric pattern. The cortical arteries supplying the affected area appeared to be substi tuted by hypoplas t ic vessels (Figs. 2 C and D, 3). Al though the venous vessels were also generally diminished in caliber, in one patient the pathological cortex was crossed in its entirety by a hyper- t rophic vein of Labb6, which was careful lypreserved dur- ing the operation. In some cases the hypoplas t ic and thinned at rophic cortex appeared stretched and elevated above the level of the sur rounding normal cortex, because of fluid accumula t ion within the underlying white matter, explaining the "cystic" appearance of the lesion at the CT examinat ion (Fig. 4). In all subjects, the white mat te r un- derlying the hypovascular ized cortex had undergone a kind of polycystic t ransformation, with several fluid-con- taining cavities separated by fibrotic septa. The insula was no t recognizable in any case. At the end of the oper-

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untreatable epilepsy, which had rapidly evolved to an EEG pattern of hypsarrhythmia.

All the remaining eight children benefited from the operation: in all cases, a decrease in the hypertonia of the affected limbs was noticed in the first few days following the surgical procedure, which resulted in a better ability to extent the arm and fingers as well as in a better gait. With the exception of one child (patient 2), an improve- ment in attention, in contact with the environment, and in intellectual performance was reported by parents; better school performances were recorded in the two oldest chil- dren (patients 8 and 9).

With regard to epilepsy, five patients were considered seizure-free after the operation. However, one of these five children had a generalized seizure during an episode of fever 1 year after the surgical procedure. No more seizures were recorded in this subject in the last 3 years. One further patient enjoyed an impressive reduction in the frequency of seizures, with only rare attacks during the postoperative period. Finally, a good reduction in the frequency of seizures, with the epilepsy relatively well controlled by medical treatment, was observed in the re- maining two children.

Fig. 3A, B. Three-month-old boy with congenital hemiparesis and seizure disorder. Operative views before (A) and after (B) excision of the atrophic cerebral cortex. Note the hypoplastic cortical vessels that have replaced the normal ones and the normal appearance of the surrounding cortex. After cortical "membrane" excision the bottom of the residual cavity is evident, separated from the ventricle only by the thin wall of the ventricular ependyma

ation the ependymal lining of the enlarged underlying cerebral lateral ventricle was bulging at the bottom of the residual surgical cavity. In no instance was the ventricular system anatomically connected to the surgical cavity.

Histological findings

At the histological examination, the removed cortex was found to be severely disorganized, with a diffuse loss of neurons, gliosis, and the presence of microcalcifications.

Outcome

There was one surgical death (patient 3) dure to an abrupt and uncontrollable, massive intravascular coagulation with secondary profuse bleeding from the surgical wound, which occurred 2 h after an apparently successful opera- tion with a normal recovery from anesthesia. This child underwent the operation in a condition of systemic blood hypertension due to protracted ACTH therapy (three cy- cles). The drug had been administered in order to control

Discussion and conclusion

Congenital hemiparesis is the most frequent form of in- fantile cerebral palsy after spastic diplegia. While the lat- ter condition, together with ataxic diplegia and paraple- gia (the other forms of infantile cerebral palsy), has de- creased in recent years, the frequency of congenital hemi- paresis has remained practically unchanged [16-18]. The phenomen seems to suggest specific etiological factors as the cause of congenital hemiparesis. In fact, congenital hemiparesis appears not to have benefited from the better perinatal care nowadays available, which has facilitated the decreased incidence and severity of perinatal acci- dents, which are primarily responsible for diplegia and paraplegia [10]. With the advent of CT scanning, several studies have been carried out to correlate the clinical manifestations of congenital hemiparesis with the neuro- radiological evidence of cerebral damage, with the aim of detecting possible etiological factors and reliable prog- nostic criteria. Unfortunately, owing to the heterogeneity of the populations studied, and limits set by the merely morphological classification of the CT findings, the re- suits of this type of investigation have been rather incon- sistent.

In 1980, Kulakowski and Larroche [25] evaluated 15 cases of congenital hemiplegia. Two of the 15 infants were born prematurely. In 11 cases, abnormalities during ei- ther pregnancy or labor and delivery were reported. In 12 cases, hemiplegia was noted before the age of 2 years (the remaining three children had been first seen at the ages of 10, 14, and 14.5 years, respectively). Epilepsy was present in 10 infants. The intelligence quotient (IQ) was below, or equal to 80 in 9 cases. In 10 cases the EEG showed epilep- tic foci, mainly on one side. The CT scans revealed a unilateral ventricular dilation in 13 out of the 15 subjects, and cortical atrophy in nearly half. Cortical atrophy was

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Fig. 4 A - D . Five-month-old boy presenting with intractable seizures and hemiparesis. Coronal MRI (A) demonstrates the pres- ence of a huge polycystic fronto- temporal lesion separated from the ipsilateral dilated ventricle. The "cystic" appearance of the le- sion and the intracystic fibrotic septa are well apparent at opera- tion (B-D)

distributed according to vascular patterns and the au- thors suggested an occlusion of the middle cerebral artery as the causative factor.

Kulakowski and Larroche presumed that the vascular accident could have occurred in utero or during the peri- natal period, following exchange transfusion and umbili- cal venous catheterization, resulting in emboli reaching the brain through the foramen ovale and ductus venosus, which are patent in the neonate [26, 27]. In the same year, Koch and co-workers [23] performed CT examinations on children with cerebral palsy to search for focal lesions possibly amenable to surgical correction. Among the 80 children examined, 18 presented with a history of congen- ital hemiparesis. In 16 of these patients abnormal scans were found, half of which showed a porencephalic cyst or an atrophic process in the area of the middle cerebral artery, while the remaining 8 demonstrated slight unilat- eral dilation of the ventricular system consistent with atrophy in the region of the germinal matrix, secondary to subependymal bleeding. In 1981, Kotlarek, and co- workers [24] reported on 40 children suffering from con- genital hemiparesis evaluated by means of the CT scan. Abnormal CT findings were obtained in 37 of the 40 patients: a unilateral ventricular enlargement was noticed in 20 cases, and a cavity in the cortex and subcortical white matter within the area of the middle cerebral artery in 17. The children with cortical and subcortical lesions had moderate to severe hemiparesis and suffered more often from epilepsy. Four of these 17 children attended a school for mentally handicapped children. No differences in intellectual performance were noted between children with a left hemiparesis and those with a right-sided deficit. The same group of 17 patients had the highest incidence of

abnormalities resulting from labor and/or delivery, and of perinatal complications, although all of them were born at term. Thus, the authors concluded that CT-morphological patterns correlated well with the neuropsychological symptoms, even though they did not find a strict relation- ship between the size of the cortical lesion and the degree of intellectual impairment. They also stated that the causative factor had to be identified in an arterial occlu- sion which had occurred during delivery or within the neonatal period. However, the etiology of the arterial accident could not be explained in any of these patients.

In 1982, Pedersen and co-workers [29], in examining 83 children with spastic cerebral palsy by means of CT, found a significantly higher incidence of factors suggest- ing a vascular infarction in the hemiparetic patients than in children with other types of congenital palsy. In fact, only 6 out of their 29 subjects with hemiparesis had a normal CT scan, while the remaining 23 exhibited well- delineated areas of low attenuation indicating a vascular distribution, cerebral hemiatrophy, or a combination of both these findings. The authors, however, did not specif- ically report on the incidence of seizures in hemiparetic children, even though they stressed a higher frequency of epilepsy in patients with pathological CT scans compared to subjects with a normal CT scan, or localized ventricu- lar dilation.

In the same year, a classification of CT findings in children with hemiparetic cerebral palsy, aimed at providing prognostic indicators, was set out by Cohen and Duffner [4]. This classification was made up of six grades of lesions of increasing severity, ranging from uni- lateral enlargement of one lateral ventricle or parts of it, cavities in the cortex and subcortical white matter in the

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Table 3. Classifications of CT findings observed in congenital hemiplegia

Kotlarek et al. [24] Cohen and Duffner [4] Claeys et al. [3] Wiklund et al. [32]

Group Grade Group

1 Unilateral enlarge- 2 Unilateral ventricu- 2 ment of the lateral lar enlargement ventricle or parts of it 3 Unilateral decreased

density in the area 2 Cavity in the cortex of the centrum

and subcortical semiovale 3 white matter within the supply area of 4 Decreased density in the middle cerebral the periphery of the

cortex artery 5 Decreased density

extending from the surface of the cere- bral hemisphere into the subjacent ventri- cle

6 Small hemisphere with homolateral shift of midline structures

3 Normal 1 Normal 1

Isolated unilateral ventricular enlarge- ment with or without ventricular deformity

Cortical or subcortical lesions: a focal ischemic

lesions b cystic porencephaly c ventricular deform-

ity with hydro- cephalus

d varia (unspecified or multiple lesion)

Normal 5 Normal

Group

1 Maldevelopment

2 Periventricular atrophy

3 Cortical/subcortical atrophy

4 Miscellaneous

territory of distribution of the middle cerebral artery, to a diffuse atrophy of one cerebral hemisphere with homo- lateral shift of the midline structures. The classification was utilized with some modifications in 1983 by Claeys and co-workers [3] (see Table 3), who distinguished three main groups of children with congenital hemiparesis on the basis of CT findings: group 1: normal CT (corre- sponding to 11% of their population of 37 children); group 2: isolated unilateral enlargement (24% of cases); and group 3: cortical and/or subcortical lesions (65%). This last group, however, was further subdivided by the authors into group 3 a: focal ischemic lesions (probably of arterial origin); group 3 b: progressive cystic poren- cephaly; group 3 c: other ventricular deformities associat- ed with hydrocephalus; and group 3 d: various (unspeci- fied or multiple) lesions. Group 3 a was made up of seven patients with localized cortico-subcortical hypodensity in the territory of the middle cerebral artery, with some deformity or enlargement of the ventricular system and displacement of the midline to the same side. In three of these children a perinatal etiology was probable; five patients were mentally retarded or at borderline level, five presented with moderate hemiparesis, one with severe, and one with mild hemiparesis; five had epilepsy and spike-wave foci on the EEG. The authors based their hypothesis that the lesion detected in group 3 a children had an arterial origin on the similarity of its morphology to that of lesions found on the CT scans in adults with cerebral artery infarction [7], and concluded that the vas- cular accident probably occurred in the late prenatal or perinatal period, when adult vascular patterns are estab- lished [7].

A further classification of CT scans in children with congenital hemiparesis was recently proposed by Wik-

lund and co-workers [32], who also took into account the phase of cerebral maturat ion when the pathogenic insult probably occurs. The authors distinguished five cate- gories: 1: maldevelopmental patients with defective organogenesis or histogenesis (17 % of their 111 patients); 2: periventricular atrophy (42%); 3: cortical/subcortical (12%); 4: miscellaneous (3%), and 5: normal (26%). Two out of the 13 patients with cortical/subcortical lesions were preterm; in 12 cases the lesion was seen in the terri- tory supplied by the middle cerebral artery. Wiklund and co-workers also considered cortical/subcortical atrophy to be due to vascular occlusion.

A detailed study on cerebral infarcts with arterial oc- clusion in neonates was carried out by Barmada and co- workers, in 1979 [1]. The authors examined 592 infants at autopsy and found a 5.4% incidence of cerebral infarcts, with a slight male prevalence (6.10% to 4.39%). They stressed how the vascular accident could easily be clini- cally overlooked, as focal neurological deficits such as hemiplegia, which characterize older children and adults, were not observed in these patients, who instead present- ed a generalized hypotonia or had become suddenly lethargic. Cesarean-section delivery had been necessary for six infants (20% of the infants with cerebral infarc- tion). Large infarcts were prevalent in full-term infants, while premature infants more often had multiple small infarcts.

With regard to the topographic distribution, the mid- dle cerebral artery was involved in practically all the cases of major arterial occlusion, that is nearly half of the pop- ulation, while the remaining children were affected only by multiple small arterial lesions, some of which were without occlusion. The left middle cerebral artery was involved twice as frequently as the right. As in adults, the

full thickness of the cortex and subcortical white matter was usually affected. Among the possible etiological fac- tors, Barmada and co-workers indicated sepsis, respiratory distress, and disseminated intravascular coagulation as particulary frequent in the studied population. They also emphasized the majority (55%) of mature full-term in- fants.

In fact, intravascular thrombosis is more frequent in mature than in premature neonates; disseminated in- travascular coagulation is relatively frequent in neonates and may be caused by relatively aspecific events - idio- pathic respiratory distress, surgery, or sepsis [9, 15]. On the other hand, the authors stressed the difficulties of evaluating the pathogenetic role of many other factors such as the aspiration of meconium leading to hypoemia, acidosis, and hyperviscosity, maternal diabetes, obstetric complications, and high steroid levels in the last trimester of gestation.

In the surviving children, a diagnosis of cerebral in- farction due to arterial occlusion may be difficult, as in- farcts in early intrauterine life are followed by a focal loss of cortical neuronal cells and architectural disorganiza- tion of the cortex, closely resembling microgyria. Only when infarcts occur in late intrauterine life or in the peri- natal period do they induce abnormalities similar to those seen in adults, with cavity formation, gliosis, and possibly calcifications [27]. Furthermore, the rapid lysis of thrombi, which is characteristic in neonates because of their high levels of circulating fibrolysins [28], may make the recognition of an arterial occlusion particularly diffi- cult in infants who survived the vascular accident [1].

The topographic distribution of the lesion in all our children at the CT examination suggested the occlusion of the middle cerebral artery as the pathogenic event lead- ing to the focal atrophy and cavity formation within the underlying white matter. The surgical findings and results of the histological examination indicate that in the major- ity of cases the occlusion occurred in late intrauterine life or in the perinatal period. In fact, in eight patients the damaged cortex appeared as a thin, semitransparent layer, with barely recognizable gyri. The loss of neurons, disorganized cytoarchitecture, and microcalcifications were the more consistent microscopic findings. All of these patients were born at term; however, in four of them a history of dystocic birth was recorded, mainly due to fetopelvic disproportion requiring cesarian delivery. Perinatal asphyxia was recorded in five instances. In only one child did the pathologic cortex exhibit a microgyric pattern, suggesting that in this patient the arterial occlu- sion could have occurred early in intrauterine life; a threatened abortion had been recorded in this case.

The lesion was localized on the left in six children and on the right in three; this confirmed the left side as the preferential site for infantile vascular occlusion [1]. Seven of our children were males, a higher proportion than that usually reported in literature but corresponding to the male prevalence already described for cerebral in- farcts Ill.

In all patients the white matter underlying the affected cortex had undergone regressive phenomena, showing a polycystic appearance. In some cases the numerous cavi-

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ties of varying sizes tended to form a sort of unique large cavity crossed by thin and stretched trabeculae. In some patients, the resulting cystic lesion showed a mass effect, determining a local bulging of the skull and possibly in- terfering with the vascular supply of the adjacent normal cortex. The removal of this mass effect might account for the benefit obtained by some patients from a simple oper- ation such as a shunting of the cyst.

In 1980, Koch and co-workers [23] first carried out a CT investigation in cerebral palsy children to search for focal lesions and surgically correctable lesions. The au- thors reported on a 3.5-year-old patient, who was born at term and presented severe perinatal distress followed by hemiplegia, but who then exhibited a significant decrease in the frequency of the seizures, a better use of the paretic limb and an improvement in behavior following the in- sertion of a cystoperitoneal shunt from a "porencephal- ic" cyst in the parietal region.

The advantages of the surgical removal of the patho- logical cortex must be identified in the elimination of an organic and functional lesion, mainly responsible for the epilepsy, which eventually interferes with the maturation of the brain as well as with the possible development of compensatory functional mechanisms. In fact, after the removal of the atrophic cortex all of our eight patients who survived the operation had a significant reduction of epilepsy. Seizures disappeared completely in five, became sporadic in one, and were significantly reduced in two cases. Thus, according to Engel's classification [8], our outcomes with respect to seizures could be classified as follows: class I: 5 cases; class II: 1 case; class III: 2 cases

- a distribution which indicates that surgical treatment may play an effective role in the treatment of this type of pathological condition. Indeed, there were no class IV outcomes, i.e., "no worthwhile result" or worsening of seizures in this series.

In the majority of patients, an improvement in dexter- ity of the affected limbs, in intellectual performance, and in behavior was observed following the operation. On the basis of this relatively small experience, it is not possible to establish whether this type of result should be correlat- ed with the reduction in the frequency of seizures, or whether it represents the direct effect of the removal of the pathological cortex, favoring the recovery of the whole brain and the development of compensatory func- tions. If this latter hypothesis is correct, the obvious im- plication could be that the surgical treatment should be performed as early as possible in order to allow the plas- ticity of the developing brain to exert its maximum bene- fit.

The studies carried out by other authors demonstrate how difficult it is to correlate a circumscribed lesion of the brain to specific performances in children, even though there is a general agreement that early focal cere- bral lesions may result in a global reduction in cognitive development [2, 11, 31]. With regard to the risk of surgi- cal treatment, we would like to emphasize that the only death we recorded was due to postoperative diffuse in- travascular coagulation. In our opinion, this complica- tion can hardly be referred to surgical stress, as the surgi- cal procedure (corticectomy) is relatively light compared

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wi th o the r types o f ope ra t ions , which are on ly in excep- t iona l cases fo l lowed by d i s tu rbances in b l o o d coagu la - t ion. Howeve r , we can n o t es tabl i sh whe the r the diffuse i n t r avascu l a r c o a g u l a t i o n we obse rved was due to a na tu - ral t endency o f ou r chi ld to deve lop t h r o m b i (a phe- n o m e n o n poss ib ly respons ib le also for its o r ig ina l vascu- lar accident) , o r to the effect o f the p r o l o n g e d s te ro id t he r apy admin i s t e r ed to con t ro l the epi lepsy.

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4. Cohen ME, Duffner PK (1981) Prognostic indicators in hemi- paretic cerebral palsy. Ann Neurol 9:353-357

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