Positional Moulding in Premature Hydrocephalics

Raj Kumar

Department of NeurosurgerySanjay Gandhi Postgraduate Institute of Medical Sciences,

Lucknow - 226 014, India.

Summary

Seven premature hydrocephalics presenting with lambdoid positional moulding (LPM)were reviewed. All were treated for hydrocephalus secondary to aqueductal stenosis,Dandy Walker Syndrome and infection. Parenchymal hemorrhage, intraventricular bleed,cortical atrophy, septal agenesis, cortical anomalies and subdural hygroma were the othercommon associations. These children did not show expected improvement in their highermental functions at 6 months to 5.4 years of follow-up, following the management ofhydrocephalus. It was not the LPM but associated intracranial anomalies, which weremost probably responsible for their poor outcome. The differentiation from posteriorplagiocephaly is also highlighted.

Key words : Positional moulding, Craniosynostosis, Lambdoid positional moulding.

Neurol India, 2002; 50 : 148-152

Introduction

Lambdoid positional moulding (LPM), expressed byasymmetrical head shape, is on the rise among infantsand pediatric population.1 Posterior headdeformations are rarely associated with lambdoidsuture fusion and must be differentiated from truelambdoid synostosis (posterior plagiocephaly).2 Manycases of LPM have been labelled as posteriorplagiocephaly in literature, hence, the differentialdiagnosis between the two is very important whiledeciding the approach and management. Thiscondition is associated with many other congenitalanomalies i.e. occult spinal defects, common birth

related trauma, torticollis, hydrocephalus and braintumors.3 The current literature describes the LPMmainly in infants and small children up to someextent, but its occurrence and associations inpremature babies have not been described.

The present paper deals with seven prematurehydrocephalics presenting with lambdoid positionalmoulding, the associations of LPM and outcome ofthese children, following treatment.

Material and Methods

Seven premature babies, who had undergone shuntCSF diversion (between years 1993 and 1999) forhydrocephalus, were evaluated for their asymmetricalhead deformation and followed in OPD. Details of

148Neurology India, 50, June 2002

Correspondence to : Dr. Raj Kumar, Department ofNeurosurgery, Sanjay Gandhi Postgraduate Institute ofMedical Sciences, Lucknow - 226 014, India.E-mail : rajkumar@sgpgi.ac.in

ORIGINAL ARTICLE

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oulding in Prem

ature Hydrocephalics

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Table I

The Clinical Profile of Seven Children of LPM

Case Age at Status of Prematurity Diagnosis Sutures and Follow-up No. presentation side of LPM following shunt

1. 3.5 years 7 months gestation, Gross ventriculomegaly, Lambdoid sutures patent, At 1.5 year :twins agenesis of septum, right right LPM. mentally retarded,

parieto-occipital periventricular unable to stand,porencephaly, thin cortical monosyllable speech.mantle, aqueductal stenosis

2. 2.5 years 7.5 months gestation, Dandy Walker Syndrome, Lambdoid sutures Six months followingjaundice neonatorum, cortical atrophy, Intraventricular open, right LPM. shunt- milestonesoff and on fever, required bleed, subdural hygroma, / ? delayed ventricular incubator for one month pachygyria, bifrontal dilatation +, seizures,

sequestrated ventricles, functioning shunt.porencephaly

3. 1 year 8.2 months gestation, Hydrocephalus Lambdoid sutures open, At 5.4 years1.6 kg delayed cry, frontal porencephaly right LPM. mentally retardeddelayed milestones restless, seizures.

4. 6 years 7.5 months gestation, Hydrocephalus, aqueductal Right LPM, opened At 2 years : seizures.delayed milestones stenosis, subdural hygroma sutures At 2 years 3 months:

subdural hygroma +, blocked shunt,seizures,

5. 1 month 6.5 month gestation, Hydrocephalus, Sutures open At further 2 month : shunt1.2 kg, delayed cry, aqueductal stenosis, right LPM blocked, at 1.2 yearsfever in 1st trimester biparietal calvarial defects delayed milestones

6. 10 months 8 months gestation, 2 kg, Ventriculomegaly, Left sides At 1.5 years : speaks incubated for one month, enhancing ependyma, LPM sutures patent. common words achievedseizures since birth, no active infection normal milestones walksfever 2 months briskly, seizures controlled

7. 8 days 8 months gestation, Hydrocephalus, Left LPM, At 2 years :occipital encephalocele Dandy Walker variant, subdural hygroma achieved normal milestones

occipital encephalocele, started walking,small bleed in occipital speaking 2-3 words.parenchyma, Cortical atrophy

LPM = Lambdoid positional moulding, Perivent = Periventricular, ‘+’ = Positive

individual cases were recorded from case sheets,discharge summaries and follow-up files. Parents ofpatients were interrogated during follow-up, regardingthe achievement of developmental and motormilestones. A clinicoradiological work-up relatedwith positional moulding was carried out in each caseduring the first admission in the hospital. Lambdoidsutures were either assessed on bone windows of CTscan or on plain skiagrams of head or by both, in eachchild. Follow-up of these children varied from 6months to 5.4 years. Brief summary of each case ismentioned in Table I. Three cases are described indetail.

Case Report

Case 1 : Three and a half year female child (bornpremature at 7 month, twin delivery) presented withhistory of gradual enlargement and deformation ofhead since birth. She had episodic vomiting for thelast one month. On examination, the enlargement ofhead was asymmetrical posteriorly, flattened on rightside, particularly at occipito-parietal region. Headcircumference was 49 cm and biparietal diameter was28 cm. Anterior fontanelle was wide open and tense.Plain CT head revealed aqueductal stenosis with grossventriculomegaly, agenesis of septum pellucidum, andright parieto-occipital periventricular porencephaly.There was relatively thin cortical mantle (Fig. 1).Bone-window of CT scan revealed patent bilaterallambdoid sutures without evidence of fusion, thoughoccipital bone was flattened on right side. Rightventriculoperitoneal shunt was done. The CSF was

under high pressure. The child was discharged on 7thpost operative day. At 1.5 year follow-up she was alertbut mentally retarded, able to sit independently butcould not stand unsupported. Her sagittal suture wasprominent, head circumference was 60 cm and therewas no improvement in lambdoid positionalmoulding.

Case 2 : Five month male child (born premature at7.5 month with history of jaundice neonatorum;required incubator’s support for 1 month after birth)was admitted with 20 days history of progressive headenlargement, excessive cry, poor oral intake and downward deviation of eye balls noticed since birth. Onexamination, his head circumference was 46 cm,anterior fontanelle was tense and bulging andposterior fontanelle was open. Occipital flatteningwas marked on the right side. CT scan revealedcortical atrophy, grossly dilated lateral and anteriorthird ventricles and normal 4th ventricle. A largecisterna magna extending more on the left was noted.Occiput and posterior parietal region was flattered onright side. MRI revealed bilateral hemispherical thinsubdural hygroma, bifrontal symmetricalporencephalic cysts and pachygyria (Figs. 2 and 3). Inview of intermittent fever, a ventricular tap was done,which yielded 40 ml of homogeneously blood stainedCSF. Biochemical examination of CSF revealed nosuggestion of infection. The child was put on a week

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Fig. 1 : NCCT head showing ventriculomegaly, agenesis ofseptum pellucidum and right parieto-occipital porencephaliccyst communicating with right ventricle.

Fig. 2 : Sagittal MRI of case 2, depicting large lateralventricles, subdural hygroma, enlarged cisterna magna andthin cortical mantle.

long trial of acetazolamide and Ommaya reservoirwas placed for repeated tapping of CSF.Ventriculoperitoneal shunt was installed onceOmmaya tap showed clear CSF on macroscopic andbiochemical examination. At 6 month follow-up, thechild developed neck holding, though othermilestones remained delayed. Occipital flatteningremained unchanged on follow-up. A repeat MRI after8 months did not reveal a significant change in theventricular size despite having digitally and clinicallyfunctioning shunt. This could have been due to pre-existing cortical atrophy.

Case 3 : A 10 month old male (born premature at 8months, having birth weight of 2.0 kg and requiredincubator for 1 month following delivery) wasadmitted with history of progressive head enlargementand head deformity since birth. He developedgeneralized seizures following delivery. History ofintermittent fever was present for the last two months.He was receiving phenobarbital in a dose of 30mg/day. Milestones were delayed historically.Anterior fontanelle was full, head circumference was43 cm. The head was flattened posteriorly on left side,left ear was relatively placed anteriorly and the leftfrontal region was prominent (Fig. 4). No apparentcranial nerve deficit could be demonstrated. CECTscan head revealed gross ventriculomegaly with slightenhancement of ventricular ependyma on contrastinjection, but ventricular CSF was not suggestive ofinfection. Ventriculoperitoneal shunt was performed ;ventricular CSF was documented to be under high

pressure. The child was alert, accepting orally andseizures free but fullness of fontanelles was noted onthe 7th post operative day. CT scan showed a decreasein the size of the ventricles with bilateral subduraleffusion. CT bone windows revealed open lambdoidsutures. At one and half year follow up, his headcircumference was 43 cm with pronounced occipitalflattening on left side. His milestones revealed gradualimprovement : uttering sentences of 2 - 3 words, hewas able to walk briskly.

Discussion

Lambdoid positional moulding (LPM) is a conditioncharacterized by occipital flattening, alopecia,anterior displacement of ipsilateral ear and the petrousand frontal bones.2 LPM is rarely associated withlambdoid suture fusion (posterior plagiocephaly),hence the differentation between the two is essentialfrom the management point of view. Unlike inlambdoid synostosis, in LPM there is no lambdoidsuture fusion. The overall incidence of LPM isunknown. Dunn reported an incidence of atleast 1 in300 of plagiocephaly in neonates.4 Muakkassa studied74 patients treated for apparent lambdoid synostosis,comprising 18.5% of their 404 craniosynostosispatients. However, 52 (13%) of these patients hadoccipital moulding deformities with sclerosis alongthe lambdoid suture margin and not true suturefusion.5 The etiology of LPM is less understood.Clarren suggested that when a rapidly growing fetal

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Fig. 3 : MRI, coronal section of case 2, demonstratingbifrontal porencephalic cysts/ ? sequestrated ventriclesadjacent to anterior part of lateral ventricles. There issuspicion of pachygyria of right cortex posteriorly.

Fig. 4 : Photograph of vertex of a child showing left LPM andanterior placement of left ear and slight left frontalprominence.

head is maintained in an abnormal intrauterineposition, calvarial moulding occurs.6

It is well known that positioning in neonatal periodcan affect head shape, an example is Scaphocephalicappearance of premature infants maintained with headin lateral, constrained position is one such example.Incidentally, the classical positional head mouldinghas been recognized amongst the flat headed Indiansof North America.2 It seems that prematurity is one ofthe important predisposing factors in the developmentof LPM . It is apparent that if a supine position oranother particular position is maintained constantly inprematures for long periods, it may result into LPM,as it had probably occurred in seven premature babiesin our study. In one of these (the case of twin births),intrauterine constraints might have also contributed tothe moulding. Right sided LPM is reportedly morecommon and this has been noted in five of our sevencases also.

Thirty seven percent cases of LPM were found to haveassociated thinner cranial bones, wider sutures andrelatively greater cranial weight.2 Most probably allthese factors remained contributory in these prematurebabies because all had hydrocephalus. Neurologicaldevelopmental delay was observed in 19% cases andsystemic abnormalities in 42% cases of LPM. Twentyeight percent cases, however, may have noassociation. A constellation of other neurologicalconditions was noted in 20% cases. These includedhydrocephalus, intraventricular hemorrhage, CNSperinatal trauma or infection, Dandy Walkermalformation, spina bifida and cerebellarhemorrhage.2 The other neurological manifestationsincluded subdural hygromas, mild communicatinghydrocephalus and atrophy. Hydrocephalus remainedthe presenting feature amongst all the prematurebabies in the present report. Aqueductal stenosis wasresponsible for hydrocephalus in three, while DandyWalker syndrome in two, a possible infective origin inone. Etiology of hydrocephalus could not beascertained in one child. Intraventricular and smallparenchymal hemorrhage was seen in one case each,porencephalic cyst in three, subdural hygroma (withhydrocephalus) and cortical atrophy in three, agenesisof septum pellucidum in one, biparietal calvarialdefect in one and meningoencephalocele in onepatient were the other associations. Developmentaldelay remained a constant feature amongst six of thesechildren. Case no 4, where there was no other cranialanomaly, developed an average intelligence. Thedevelopmental delay was most probably on account ofassociated cranial cortical/ventricular abnormalities.A high frequency of associated CNS anomalies

emphasize the need for thorough neurologicalevaluation and neuroimaging studies in these children.Development of seizure was observed in five of ourchildren during follow-up.

The vast majority of children labelled as posteriorplagiocephaly did not have true synostosis, but hadpositional moulding.2,7 The differentiation betweenthe two is very important in view of their divergentmanagement. The routine use of CT, supplemented ifnecessary by three dimensional recontruction forcases where the patency of lambdoid suture is inquestion on plain radiographs, facilitates a morerealistic assessment of true lambdoid synostosis.7 Inview of patent sutures in positional moulding, thesechildren have relatively normal growth potential ofcranium, unlike the posterior plagiocephaly. There is astrong argument to manage these childrenconservatively, at least initially, as the compensatorycontralateral occipital or ipsilateral frontal growthprovides enough room for the growing brain. Thetreatable associated cranial anomalies may requiresurgical intervention, as was carried out in ourchildren, mainly for hydrocephalus.

In summary, premature children with hydrocephalushave relatively more frequency of LPM in comparisonto posterior plagiocephaly. This apparently may bebecause of the maintenance of supine position with athin calvarium and heavy weight of head due tohydrocephalus. The developmental outcome in thesecases is poor, not because of LPM but because ofassociated anomalies.

References

1. Najarian SP : Infant cranial moulding deformation and sleepposition : Implication for primary care. J Pediatr Health Care1999; 13 : 173-177.

2. Chadduck WM, Kats J, Donahue DJ : The enigma oflambdoid positional moulding. Pediatr Neurosurg 1997; 26: 304-311.

3. Mc Gee S, Burkett KW : Identifying common pediatricneurosurgical conditions in primary care setting. Neure ClinNorth An 2000; 35 : 61-85.

4. Dunn PM : Congenital sternomastoid torticollis : Anintrauterine postural deformity. Arch Dis Child 1974; 49 :824.

5. Muakkassa KF, Hoffman JH, Hinton DR et al : Lambdoidsynostosis. Review of cases managed at the Hospital forSick Children 1972 - 1982. J Neurosurg 1984; 61 : 340-347.

6. Clarren SK : Plagiocephaly and torticollis : Etiology, naturalhistory, and helmet treatment. J Pediatr 1981; 98 : 92-95.

7. Pollack IF, Kosken W, Fasick P : Diagnosis andmanagement of posterior plagiocephaly. Pediatric 1997; 99: 180-185.

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Accepted for publication : 25th November, 2000.