Growing skull fractures: classification and management

British Journal of Neurosurgery ( 1994) 8, 6 6 7 - 6 7 9

ORIGINAL ARTICLE

Growing skull fractures: classification and management

N A I M - U R - R A H M A N , Z A I N A L A B E D E E N B . J A M J O O M , A B D E L H A K I M B .

J A M J O O M & W A L E E D R . M U R S H I D

Division of Neurosurgery, College of Medicine, King Saud University & King Khalid University

Hospital, P.O. Box 2925, Riyadh 11461, Saudi Arabia

A b s t r a c t Seven patients with growing skull fractures treated between 1983 and 1993 are described. These growing fractures constituted 1.6% of all the cases of skull fractures seen during the period (a total of 449 cases). Based on aetiopathogertesis, computed tomography (CT) appearances, operative findings and management strategies required, three main types of growing skull fractures were recognised. In type I (n 3) a leptomcningcal cyst, in type II in = 3) damaged and gliotic brain, and in type III (n = 2) a porencephalic cyst extended through the skull defect into the subgalcal space. A combination of type I and type III co-existed in one patient. Initial head injury and neurological deficit were judged to be mild to moderate in all the seven cases. Continued growth of skull fractures correlated closely to the increasing neurological deficit in five cases. In two patients natural arrest of fracture growth at 5 and 7 months after trauma was accompanied by arrest in progress of neurological deficit. Available surgical options are discussed and general guidelines for the management are given.

Key w o r d s : Trauma, lepzomeningeal cyst, porencephalic cyst, meningocele spuria, progressive neurological deficit, skull

fracture

Introduction

Linear or non- l inea r skull fractures in chil­

d r e n tha t enlarge wi th t ime are t e r m e d g row­

ing skull f rac tures . 1 A l t h o u g h these lesions are

m u c h m o r e c o m m o n i n ch i ld ren , 2 and 9 0 %

occur u n d e r the age of 3 yea r s ; 3 the p rocess

m a y occur following a skull f racture in an

a d u l t . 2 , 4 , 5 T h e inc idence of ' g rowth ' as a de ­

layed compl ica t ion of skull fracture is rare a n d

occu r r ed in only 0 . 6 % of the cases in o n e large

ser ies , 6 I t is i m p o r t a n t to realize tha t t he lesion

e x p a n d s n o t only b e t w e e n the fracture edges ,

b u t also intracranial ly a n d , t h u s , m a y cause

a t rophy of unde r ly ing cerebral t issue wi th r e ­

sul t ing progress ive neurological deficit; 7 as was

seen in m o s t of our cases. Because of the

diverse clinical, radiological ( C T ) a n d ope ra t ­

ive f ind ings a n d variable t e m p o r a l course ,

there i s cont roversy conce rn ing the t e rmino l ­

ogy, ae t iopa thogenes is and m a n a g e m e n t of

g rowing skull f r a c tu r e s . 3 ' 6 , 8 Classification of

t he growing skull fractures into t h r ee types

(Fig . 1) sugges ted he re was found to be he lp ­

ful in explaining these diversit ies a n d p l a n n i n g

the t r e a t m e n t . Similarly, based on the clinical

p resen ta t ion a n d t e m p o r a l cour se , two forms

of the growing skull f ractures could be dis­

t inguished. An active form wi th evidence of

raised int racranial p ressure ( I C P ) , mass effect

on C T , progressive separa t ion o f b o n e edges

wi th a tense bu lge b e t w e e n t h e m ; and an a r -

667

668 Naim-Ur-Rahman et al.

Searr td arachnoid

T Y P E m

FIG. 1. The three main types of the growing skull fractures.

res ted or ' b u r n t o u t ' form with a n o r m a l I C P ,

a n d a s lack/sunken gap be tween the b o n e

edges often showing some ev idence of b o n e

regrowth and heal ing at the fracture site.

Duro -c ran iop las ty was t he cor rec t t r e a t m e n t

for type I fractures w i t h o u t ra ised int racranial

p ressure ; whereas a shun t ing p r o c e d u r e was

requ i red as an initial or definitive m a n a g e m e n t

for type I a n d III fractures with ra ised in t racra­

nial p ressure .

Report of cases

A s u m m a r y of t he seven pa t i en t s is p re sen ted

in T a b l e L a n d m a n a g e m e n t op t ions s u m m a ­

rized in T a b l e I I I .

Clinical Data

Six pa t i en t s were ch i ld ren while o n e was 39

years old. In t he paed ia t r i c g r o u p , t he age at

the t ime of diagnosis r anged from 4 m o n t h s to

Growing skull fractures 669

6 years (mean : 2 4 , 6 m o n t h s ) . Six pa t i en t s

were female a n d o n e ma le . T h e interval be ­

tween the his tory o f h e a d injury a n d diagnosis

of growing skull f racture r a n g e d from 2

m o n t h s to 1 year ( m e a n : 7 m o n t h s ) . L o c a t i o n

of t he skull f racture was par ie ta l in th ree

pa t i en t s , f rontoparietal in one , occipi topar ie ta l

in one , and occipital in t he r ema in ing two

chi ldren.

T w o chi ldren (cases 1 and 2) h a d exper i ­

enced p e r m a n e n t remiss ions after a per iod of

active fracture g rowth . T h e r ema in ing f ive

showed evidence of ra ised int racranial press­

u r e a n d m o r e or less progress ive neurological

deficits. Five chi ldren p r e s e n t e d wi th swelling

in the region of t he fracture site, while in two

(cases 1 and 7 ) , t he a rea b e t w e e n the gaping

b o n e edges was slack and depressed . Seizures

a n d h e m ip a re sis were the nex t c o m m o n

presen t ing s y m p t o m s a n d occu r r ed in four

pa t ien t s . Bl indness or progressive visual

de te r iora t ion was p resen t in two ch i ld ren with

occipital fractures, whi le r e t a rda t ion was seen

in o n e child.

Radiological evaluation

Plain r ad iographs o f t he skull a n d CT were

pe r fo rmed on all pa t i en t s . Skull r ad iographs

correctly d e m o n s t r a t e d the locat ion a n d ex ten t

of separa t ion of b o n y edges at the fracture site.

Extens ive b o n y resorp t ion wi th widely gaping

everted fracture m a r g i n s , seen in three chil­

d r e n , corre la ted well with t he size of the u n ­

derlying cyst a n d b ra in d a m a g e on a CT scan.

C T clearly d e m o n s t r a t e d t he b o n y defect ,

the n a t u r e of in t racrania l c o n t e n t s he rn ia t ing

t h r o u g h it ( l ep tomeningea l cyst = 3, con tused

cerebral t issue = 3, po rencepha l i c cyst -2);

a n d the ex ten t of the under ly ing int racranial

lesion. T h u s , a l ep tomen ingea l cyst wi th C S F

densi ty was seen in three pa t i en t s , extensive

low densi ty areas of b ra in d a m a g e a n d en-

cephalomalac ia in three pa t ien ts a n d p o r e n ­

cephal ic cysts c o m m u n i c a t i n g wi th di la ted

ventr icles in two chi ldren.

Operative findings

Five of the seven pa t i en t s u n d e r w e n t surgery.

O n e child (case 4) h a d a vent r icu lopcr i tonea l

s h u n t for tense po rencepha l i c cyst a n d di la ted

ventr icles . In t he r ema in ing four chi ldren t he

defect was repa i red by durop las ty us ing fascia

lata or per icrania l graft, a n d an acrylic c ran io-

plasty. Of these four ch i ldren w h o u n d e r ­

w e n t c ran io tomies a t t he fracture sites, two

(cases 2 a n d 4) s h o w e d that the scalp and

p e r i c r a n i u m were densely adhe ren t to the

unde r ly ing conges ted , gliotic a n d he rn ia t ed

bra in . T h e d u r a was totally absen t u n d e r the

cranial defect. M o r e or less extensive n ibbl ing

of t he marg ins of b o n e defect was requ i red to

f ind a reasonab le dura l edge . Dissect ion and

elevation of the scalp f lap from the unde r ly ing

conges ted gliotic bra in was t ed ious a n d ac­

c o m p a n i e d by m u c h bleeding. In case 5 , oper ­

a t ion was pe r fo rmed for a large tense occipital

swelling t h r o u g h a growing fracture of the

skull. E levat ion of a large occipital scalp flap

revealed a po rencepha l i c cyst on the right side

and a l ep tomeningea l cyst overlying a con ­

gested a n d softened left occipital lobe . T h e

occipital cyst was aspi ra ted and an acrylic

cranioplas ty carr ied ou t . Duroc ran iop la s ty was

s t ra ightforward in the seventh case.

Surgical results

C o m p l e t e reso lu t ion of t he ra ised in t racrania l

p res su re , extracranial swelling a n d progress ive

c losure of skull defect was ob t a ined in t he

child w h o u n d e r w e n t s h u n t surgery (case 3) .

Fo l l ow-up at 3 a n d 6 m o n t h s has s h o w n re­

duc t i on in t he size of cranial defect with evi­

d e n c e of b o n e r eg rowth a t t he fracture site.

C o m p l e t e obl i te ra t ion of t he cranial defect was

achieved in t h r ee ou t of four pa t i en t s w h o

u n d e r w e n t duro-c ran iop las ty ( m e a n follow-

u p : 4 years) . In t he four th pa t i en t , t he acrylic

plate loosened a n d bu lged 2 years after

surgery. Reope ra t i on was refused. All the f ive

pa t ien ts who u n d e r w e n t surgery recovered

wi thou t any increase in t he pre-exis t ing n e u r o ­

logical deficits and definite i m p r o v e m e n t was

r eco rded in four pa t i en t s .

Case 1. T h i s 3 0 - m o n r h - o l d girl was well unt i l

10 m o n t h s before admiss ion w h e n she was

T A B L £ L Summary of seven patients with growing skull fractures - J o

Case

no. Age/sex*

Location of

fracture

Type &

temporal

classification Presentat ion and c'imca] examination

Skull

radiography

C T

appearance Treatment Outcome

5¬ 3

30 months

F

72 months

F

4 months

F

Parietal

Parietal

Occipital

15 months Occipital

I

Arrested (burnt-out)

II

Arrested

[|]

Active

36 months Frontoparietal II

h" Active

I & III

Active

Slack depression in the region of

fracture^ improving left berra'paresis,

Retardation

Slack swelling right parietal r eg ion

seizures, minimal left hemiparesis

Tense, increasing bulge overlying

left occipital bone defect.

RICPj vomitings p a p i l l e d e m a ,

?Blindness

T e n s e swelling left forehead,

occasional headaches and vomiting,

seizures, Q progressive) right

hemiparesis

Tense enlarging swelling occipital

region, blindness, progressive

neurologic deficits

Gaping bone

defect with

everted margins

Gaping defect

right parietal

Large, wedge-

shape bone gap

with extensive

re^irprion

Atrophic (drained) right

parietal leptomeningeal

cysts with ipsila i :ral

pulling of midline

Low density, atrophic

cerebral tissue

underlying skull defect

I-argc left oceipital

porencephalic cyst

communicating with

the dilated lateral

ventricles and

herniating through the

occipitoparietal defect

Extensive gaping

fracture left

fronto-parietal

involving anterior gaping fracture

cranial fossa

Low density atrophic

cerebral tissue

herniating through

Gaping,

bioccipital

bony defects

Conservative

? Spontaneous cure

Duropla&ty and acrylic

craniopiasty

Cysto- ventricuiop eritoneal

shunt

Bilateral occipital

cephalomalacia ? large

right occipital

porencephalic cyst

communicating with

dilated lateral

ventricles and

herniating through bone

defect +• left

leptomeningeal cyst

Duroplasty and acrylic

craniopiasty

Acrylic craniopiasty

followed by

recurrence,

followed by repeat

duro-cranioplasty

Being followedjf

Evidence of

improving deficits

and bone regrowth

at fracture site

C u r e d !

Curedf

Recurrence!

after surgery

Improved!

Followed-up to 3

years has

defective vision

V.E.P. = poor

response =

cortical

blindness

672 Naim-Ur-Rahman et al.

T A B L E II. Management options

Growing skull fracture

With normal 1CP

With raised 1CP

Tense porencephalic cyst with

hydrocephalus

Ventri c ulo peritoneal shunt

I I I

I

Tense leptomcningcal

cyst

Cysto-peritoneal

shunt

I

I

Duro-cranioplasry

t rea ted for h e a d injury with a fracture of t he

skull. Over t he nex t 5 m o n t h s the child devel­

o p e d bu lg ing of t he scalp in t he right par ie ta l

region which b e c a m e progressively larger.

T h i s was a c c o m p a n i e d by progress ive left

h e m ip ares is, h e a d a c h e , vomi t ing and oc­

casional seizures. Five m o n t h s p r io r to ad­

mission the m o t h e r no t i ced a s p o n t a n e o u s

i m p r o v e m e n t in chi ld 's cond i t ion . T h e scalp

bulge b e c a m e softer t h e n rapidly d i sappea red

leaving a depressed gap be tween the b o n e

edges . T h i s was a c c o m p a n i e d by reso lu t ion of

h e a d a c h e a n d vomi t ing , a n d i m p r o v e m e n t in

t he left-sided weakness . T h e chi ld was admi t ­

ted to t he neurosurg ica l un i t wi th the chief

compla in t s of a soft gap on r ight s ide of head ,

seizures and res idual left hemipares i s . E x a m i n ­

at ion revealed a par ie ta l b o n y defect wi th a

slack depress ion , in an alert girl walking inde ­

penden t ly . Neuro log ica l examina t ion showed

min imal left hemipares is with pyramida l signs

a n d mi ld re ta rda t ion . Skull r ad iographs on

admiss ion showed a gaping r ight par ie ta l frac­

tu re wi th ever ted saucer ized marg ins . C T

(Fig. 2) showed a l ep tomeningea l cyst u n d e r ­

lying the cranial defect and c o m m u n i c a t i n g

freely wi th t he pc r imesencepha l i c cistern. As

there was evidence of regrowth of b o n e edges

(Fig, 2) a long with c o n t i n u e d i m p r o v e m e n t in

h e r neurological s ta tus , i t was dec ided to o b ­

serve. At 3 - m o n t h fol low-up the b o n e gap had

n a r r o w e d .

Case 2. T h i s 6-year-old girl p re sen ted wi th

seizures and a 'soft a r ea ' over t he r ight par ie ta l

region, no t i ced for the last 4 years . A h e a d

injury h a d occur red w h e n the child was 10

m o n t h s old. O n e year after t he head injury t he

pa ren t s no t i ced a soft, gradually increas ing

bu lge in the right par ie ta l region which g radu­

ally 'flattened* in t ime leaving a 'soft a rea ' .

T h e r e was no his tory of h e a d a c h e or vomit ing .

E x a m i n a t i o n revealed an alert , b r igh t child. A

skull defect in t he r ight par ie ta l region m e a s u r ­

ing a b o u t 4 cm and covered by slack scalp

cou ld be felt. Neuro log ica l examina t i on re ­

vealed m i n i m a l left hemipares is with brisk ten­

d o n jerks. T h e r e was n o p a p i l l e d e m a . Skull

r ad iograph (Fig. 3) showed a gap ing fracture

in r ight par ie ta l region. CT (Fig. 4) s h o w e d a

low densi ty lesion of the unde r ly ing bra in with

slight d i la ta t ion a n d ipsilateral 'pul l ing ' of the

right lateral ventr icle . At ope ra t ion , a large,

Growing skull fractures 673

k A FCG. 2, Case 1: CT scan showing lcptomeningeal cyst underlying cranial defect and its communication with the perimcscncephalic cistern (arrow). Note regrowth of fracture edges.

righi fronto-parietal scalp flap was raised.

D e n s e adhes ions b e t w e e n the scalp a n d u n ­

derlying bra in were dissected. F r a c t u r e edges

were n ibb led to expose n o r m a l du r a . T i s sues

were abnormal ly vascular and bled excessively.

Durop la s ty a n d acrylic cranioplas ty was car­

ried ou t . Pos topera t ive ly t he p a t i e n t d id very

well a n d was d i scharged h o m e on pheny to in .

T h r e e years la ter , she i s a s y m p t o m a t i c a n d

free of seizures.

Case 3. T h i s 6 - m o n t h - o l d girl was seen in the

neurosurg ica l clinic wi th t he his tory tha t she

fell a n d s t ruck the b a c k of her h e a d on a

conc re t e f loor at t he age of 1 m o n t h . Shor t ly

af terwards , a bu lge was no t i ced in t he left

occipi to-par ie ta l region . T h i s bu lge b e c a m e

progressively larger and tense . On admiss ion

the child was irr i table, refused feeds a n d had

b e e n vomi t ing for pas t few days . Skull r ad io ­

graphs showed a widely gap ing w e d g e - s h a p e d

b o n e defect wi th extensive resorp t ion in the

left occipi to-par ie ta l region. CT (Fig. 5a and

b) showed a large po rencepha l i c cyst c o m m u ­

nica t ing with t he occipi ta l h o r n of a d i la ted left

lateral ventr ic le a n d he rn ia t ing t h r o u g h the

wide b o n y gap in to t he tense occipital bulge .

T h e child was t rea ted wi th vent r icu lo-per i -

toneal s h u n t following which the occipital

bu lge a n d h y d r o c e p h a l u s resolved. At follow-

up examina t ions at 3 a n d 6 m o n t h s , t he child

was thr iving, the occipital bu lge had d i sap­

peared and the b o n e defect was m u c h smaller ,

FlG. 3. Case 2: skull radiography, lateral view, showing a widely gaping parietal fracture.

F l G . 4. Case 2: CT scan showing the right parietal bone defect and the underlying low-density brain lesion.

6 7 4 Naim-Ur-Rahman et al.

F I G . 5. (a) and (b) CT scans shown a large left occipital ventricle (a) and herniating, through the wide bony gap

with definite evidence of b o n e re -growth at the

fracture edges .

Case 4. T h i s 3-year-old girl was originally

a d m i t t e d a n d t rea ted elsewhere for a l inear

fracture of left f ronto-par ie ta l region. Seven

m o n t h s after t he original h e a d injury, she was

admi t t ed to o u r neurosurg ica l un i t because a

bu lge h a d deve loped over t he left forehead

which b e c a m e progressively larger. T h e r e was

a his tory of occasional h e a d a c h e s , vomi t ing ,

seizures a n d progressive right hemipares i s du r ­

ing the p reced ing 3 m o n t h s . On examina t ion

there was a tense l inear swelling in t he left

forehead ex tend ing f rom the left f ronto­

par ie ta l region to the supra-orb i ta l marg in

and roo t o f t he nose . T h e marg ins o f t he

unde r ly ing skull defect could be pa lpa t ed . She

had mi ld weakness o f r ight a r m a n d leg b u t

no p a p i l l e d e m a . Skull r a d i o g r a p h (Fig. 6)

showed a l inear defect in the left f ronto­

par ie ta l region ex tend ing to the supraorbi ta l

marg in . CT (Fig. 7 ) showed the gaping frac­

tu re a n d an under ly ing low densi ty b ra in

lesion. At ope ra t ion , a large f ron topar ie to-

t e m p o r a l scalp flap was raised. U n d e r n e a t h

t he flap an adhe ren t l inear bu lge of gliotic

b ra in was seen b e t w e e n the gaping fracture

edges . T h i s he rn ia t ed cerebral t issue, e x t e n d -

porcnccphalic cyst communicating with a dilated lateral (b).

ing from coronal s u t u r e to t he supra-orb i ta l

marg in , was tense , conges ted and b led easily.

D u r a l repa i r with fascia lata a n d craniopias ty

wi th methyl me thac ry la te was carr ied ou t . T h e

pos topera t ive course was unevent fu l a n d the

child was d i scharged h o m e , free of h e a d a c h e ,

b u t wi th res idual mi ld r ight-s ided weakness .

F o l l o w - u p at 2 years showed tha t the im­

p l a n t e d plast ic was loose and bu lg ing over a

tense cystic swelling. Reopera t ion was refused.

Case J . T h e p a t i e n t was originally admi t t ed to

t he neurosurg ica l un i t at the age of 9 m o n t h s

following a r o ad traffic acc ident . On ad­

miss ion , she was drowsy, b u t w i t h o u t any a b ­

n o r m a l neuro logica l findings. A r a d i o g r a p h of

t he skull showed an obl iquely p laced f issure

fracture of t he skull cross ing the midl ine just

above torcula a n d C T showed this fracture

wi th min ima l con tus ion of t he occipital lobes

(Fig. 8 ) . T h e b a b y recovered rapidly from the

h e a d injury and was d i scharged h o m e after 5

days. Six m o n t h s later (at t he age of 15

m o n t h s ) she was r e -admi t t ed with a tense

swelling in t he region of the occipital f racture

site and a suspic ion of progressive visual loss.

T h e occipital swelling h a d b e e n gradual ly en­

larging d u r i n g the weeks p r io r to re -admiss ion .

Examina t i on n o w revealed that a l though the

Growing skull fractures 675

FlG. 6. Case 4: skull radiograph, AP view, showing a gaping linear defect (arrows) in the fronto-parictal region.

F I G . 7. Case 4: CT scan showing the left frontal growing fracture (arrows) and the underlying low density brain lesion.

child could see, t he vision was clearly defective

as shown by h e r inabili ty to fixate and lack of

reac t ion to visual s t imuli . R e a c t i o n of t he

pupi l s to the l ight was very sluggish b u t equal .

Visual evoked potent ia ls (VEP) conf i rmed

cortical b l indness . Plain r ad iography of the

skull on this second admiss ion showed a large,

occipital b o n y defect wi th scal loped margins

(Fig . 9) . CT a t this stage showed resorp t ion of

a po r t ion of t he occipital b o n e a n d under ly ing

b ra in lesions (Fig. 10). At surgery, the C S F -

conta in ing occipital cyst was aspi ra ted and an

acrylic cranio plasty carried o u t . T h i s child was

r e - admi t t ed 2 m o n t h s later, this t ime wi th a

collection of f luid u n d e r t he acrylic c ran io-

plasty. A fur ther ope ra t ion was carr ied ou t . A

water - t igh t repa i r of the dura l defect was

achieved us ing a per icrania l graft a n d a fresh

cranioplas ty was pe r fo rmed . T h e pos tope ra ­

t i ve course was unevent fu l a n d the w o u n d

healed satisfactorily. Review 3 years later

showed defective vision.

Case 6. T h i s child was hospi ta l ized for 3 days

for h e a d injury at the age of 5 m o n t h s . Skull

r ad iography and CT showed a left pa r i e to -oc -

cipital f issured fracture of skull with m i n i m a l

unde r ly ing con tus ion (Fig. 11) . N i n e m o n t h s

later she p r e s e n t e d with a large skull defect

a n d tense scalp swelling at t he site of the

fracture , a long wi th increasingly f requent

seizures a n d delayed speech . Rad iography now

showed a large, gap ing skull defect at t he site

o f original f racture (Fig. 12) a n d CT showed

the gaping fracture wi th hypodens i ty of the

unde r ly ing b r a i n and d i la ta t ion of t he ipsilat-

eral ventr icle (Fig. 13) . Surgery was refused in

spite of progress ive neurological a n d radiologi­

cal de te r iora t ion .

Case 7. A 39-year-old w o m a n was seen for

increas ing r ight -s ided h e a d pa in . At t he age of

18 years she h a d suffered a h e a d injury in a car

acc ident . On examina t ion , a large gaping skull

defect was p resen t in the r ight parietal region.

Skull r ad iography showed a widely gaping

right par ie ta l defect (Fig. 14) , CT showed the

skull defect a n d unde r ly ing lep tomeningea l

cyst (Fig. 15). Duroc ran iop la s ty was s t ra ight­

forward, and resul ted in resolut ion of h e a d ­

ache and closure of t he skull defect.

6 7 6 Naim-Ur-Rahman et al.

FlG. 8. Case 5: CT scan at the time of initial trauma showing right occipital linear fracture.

F I G , 9, Case 5: skull radiography 6 months later showing large occipital bony defect with scalloped margins.

Discussion

G r o w i n g skull fracture has b e e n descr ibed in

t he l i terature as an ent i ty s y n o n y m o u s to a

l ep tomeningea l cyst, 2 ' ' ' ' 9 T h u s , a p o s t t r a u m a t i c

extra axial l ep tomeningea l cyst was a s s u m e d

to be responsib le for t he progressive en la rge­

m e n t o f the skull f racture . T h e cases descr ibed

he re suggest t ha t the l ep tomeningea l cyst is

n o t a cons is ten t feature a n d tha t a variety of

progressively evolving morpholog ica l and

pa thologica l changes in the under ly ing b ra in

m a y play an i m p o r t a n t role in the genesis of

growing fractures. Morphologica l ly , the p r e ­

d o m i n a n t factor responsib le for fracture

g rowth m a y lie in t he s u b a r a c h n o i d space (a

l ep tomeningea l cyst) , c e r e b r u m (hern ia ted

bra in) or ventr icle (dilated unde r ly ing ven­

tricle with po rencepha l i c cyst) . T h e s e events

cons t i tu te the morpholog ica l basis for the frac­

tu re types I , I I and III , respectively.

At t he initial t r auma , d is tor t ion of the m a l ­

leable infant skull on i m p a c t genera tes p ress ­

u r e fields wi th in the c r a n i u m , leading to a

skull f racture a n d tear ing of t he tightly adhe r ­

en t unde r ly ing d u r a . 1 0 , 1 1 Six o f t he seven p a ­

t ients in our scries and m o s t in o t h e r ser ies 3

were chi ldren. T h u s , malleabi l i ty of t he infant

skull a n d t ighter a d h e r e n c e of dura to the b o n e

in ch i ldren m a y a c c o u n t for t he c o m m o n

occu r r ence of growing fractures in this age

g r o u p , 1 2

Pa thogenes i s of t he l ep tomeningea l cysts, as

seen in o u r cases 1, 5 a n d 7, is well descr ibed

e l s e w h e r e . 2 , 9 In type II f ractures , as seen in our

cases 2, 4 and 6, cerebral pulsa t ions e rode t he

fracture edges , a n d drive t he c e r e b r u m

th rough the dura l vent a n d b o n y gap . W i t h

t ime , t he he rn ia t ing and the under ly ing b ra in

suffers progressive d a m a g e as s h o w n by local

a t rophy a n d cepha lomalac ia . In type III frac­

t u r e (cases 3 a n d 5) , the under ly ing ventricle

expands into a po rencepha l i c cyst. T h e ent i re

ventr icle m a y dilate as was seen in case 3 or

jus t the o n e h o r n subjacent to t he growing

fracture m a y dilate as occu r r ed in case 5. In

these cases, t he po rencepha l i c cyst ex tends

from vent r icular wall t h r o u g h the skull defect

a n d into the subgaleal space , a n d is roofed by

a t h in layer of softened gliotic cor tex.

In m o s t of t he repor ted cases the initial h e a d

injury was a m i n o r o n e a n d focal neurological

deficits were r a r e . 1 1 T h u s , a t t he t ime of initial

skull fracture, only two of our pa t ien ts showed

min imal hemipares i s . Howeve r , over the e n s u ­

ing weeks or m o n t h s , all of these ch i ldren

showed evidence of m o r e or less progress ive

neurological deficits. Neuro logica l s ta tus and

fracture stabil ized, after a per iod of p r o ­

gression and g rowth , in two chi ldren. T h i s

Growing skull fractures 611

FlG. 10. Case 5: six months later. CT scan showing marked widening of the occipital fracture with scalloping of the margins and right occipital porencephaly and a left occipital leptomeningeal cyst.

resolut ion was qui te d r a m a t i c in case 1 , a n d

was t h o u g h t to be due to r u p t u r e a n d dra inage

of the l ep tomeningea l cyst into the pe r imesen -

cephal ic cistern (Fig. 2 ) ,

T h e na tura l his tory a n d t e m p o r a l course o f

t he growing skull fractures var ied from case to

case. T h e rapid progress ion with ra ised I C P

seen in case 3 , a n d s p o n t a n e o u s arrest a n d

heal ing seen in case 1, appear to be t he t w o

ends of a s p e c t r u m . Gradua l ly progress ive

neurological deficits wi th increas ing unde r ly ­

ing b ra in d a m a g e was t he m o r e c o m m o n o c ­

cur rence a n d was seen in four of o u r pa t ien t s .

In active growing skull f ractures , a t ense

overlying scalp bulge m a y indicate raised I C P

wh ich m a y be caused by a tense l ep-

tomen ingea l /po rcnccpha l i c cyst, o r pos t t r au ­

ma t i c h y d r o c e p h a l u s . 1 3 Slack scalp depress ion

at the fracture site wi th evidence of b o n e r e -

g rowth and fracture hea l ing , a long with t he

arrest of the previously progress ive neuro log i ­

cal deficits ind ica tes s p o n t a n e o u s reso lu t ion of

a l ep tomeningea l cyst, as was seen in case 1.

Gradua l ly progressive focal neurological

deficits, seen in four chi ldren , co inc ided

closely wi th the increasing separa t ion of t he

b o n e edges a t t he fracture site and CT evi­

d e n c e of ex tens ion of the under ly ing b ra in

d a m a g e . T h e n a t u r e o f these focal deficits

d e p e n d e d on the fracture site. T h u s , t he two

chi ldren wi th occipital f ractures (cases 3 and

5) suffered progressive visual loss, while he mi -

paresis was seen in t he cases wi th f ronto­

parietal fractures.

Skull rad iography a n d C T were the two

m o s t useful invest igat ions for the diagnosis

a n d m o n i t o r i n g of growing skull fractures.

T h u s , a t the t ime of t he initial t r a u m a , all the

seven pa t i en t s h a d skull r ad iographs which

showed l inear fractures. T h e initial h e a d injury

was n o t cons idered serious e n o u g h to war ran t

CT in t he f i r s t ins tance , except in cases 5 a n d

6 w h e r e CT a t t he t ime of t r a u m a conf i rmed

the f issured skull fractures w i thou t evidence of

significant con tus ions o r d a m a g e to t he u n d e r ­

lying b ra in (Figs. 8 a n d 11) . De l ayed CT

showed the fracture growth (Figs. 10 a n d 13)

a n d , m o r e impor tan t ly , appea rance o f ex ten­

sive fresh lesions with m a r k e d a n d possibly

c o n t i n u i n g d a m a g e to the under ly ing bra in

(Figs. 10 a n d 13) . CT correct ly d e m o n s t r a t e d

t he n a t u r e and ex ten t o f t he in t racrania l p a t h ­

ology inc lud ing areas of cephalomalac ia , s u b ­

dura l , l ep tomeningea l and po rencepha l i c

cysts, as well as vent r icular d i la ta t ion ( c o m ­

ple te o r only o n e h o r n ) .

Because of t he var iable pathological

f indings, t he s t anda rd surgical p r o c e d u r e d e ­

scribed in t he l i t e r a t u r e 2 ' 1 1 , 1 4 for t he t r e a t m e n t

of the g rowing skull fractures is n o t justifiable

or appl icable in all the cases. S t a n d a r d surgical

a p p r o a c h involves resect ion of t he l ep to ­

men ingea l cyst a n d he rn ia t ed b ra in , repa i r of

t he du ra l defect with a graft a n d c ran io­

p i a s t y 2 , 1 1 F o r the s t ra ightforward cases wi thou t

any evidence of raised I C P , such as our cases

2 and 7, this p r o c e d u r e is cura t ive . We have

u s e d per icranium/fascia lata a n d me thy l

methacry la te to repair du ra l and crania l de ­

fects in o u r cases; b u t o the r s have used split

6 7 8 Naim-Ur-Rahman et al.

F I G . 1 1 . Case 6: CT scan at the time of initial trauma showing left parieto-occipital fracture with minimal underlying contusion and normal ventricular system.

FLG. 1 2 . Case 6: skull radiograph, 9 months later showing large, gaping skull defect at the site of original fracture.

calvarial b o n e , r ibs , iliac cres t a n d metal l ic

mater ia ls wi th satisfactory r e s u l t s . 1 5 " 1 8 H o w ­

ever, chi ldren u n d e r 2 years of age have a skull

b o n e th ickness tha t is t oo difficult to split in

o r d e r to repair the de fec t . 1 8 In s o m e pa t ien ts ,

such as our case 4, the dural defect ex tends

well b e y o n d the skull defect , necess i ta t ing

FlG. 13. Case 6: C T s c a n 9 months posttrauma showing gaping fracture with hypodensity of underlying brain and dilatation of the ipsilateral ventricle.

FIG. 1 4 . Case 7: skull radiograph showing gaping skull defect, right parietal region.

rongeur ing b o n e edges for long d is tances in

o r d e r to expose reasonab le du ra l edges to

which the graft can be s t i tched. In o the r s , s u c h

as o u r case 5 , o n e m a y be obl iged to resect the

cortex which roofs the he rn ia t ing po ren ­

cephal ic cyst. T h i s extensive en l a rgemen t of

t he skull defect and resect ion of the possibly

Growing skull fractures 6 7 9

FlG. 15. Case 7: CT scan showing right parietal skull defect overlying a leptomeningeal cyst.

funct ional a n d viable areas of t he infant b ra in

appear to be s o m e w h a t excessive. In these

c i r cums tances , t he modif ied m e t h o d for r e ­

pa i r ing this defect , as desc r ibed by Hal l iday et

al.,"* seems m o r e app rop r i a t e . T h i s t e chn ique

involves mobi l iz ing the p e r i c r a n i u m c i r cum-

fercntially a r o u n d the edges of the bone defect

a n d reflecting i t over the site of t he dura l

defect to provide t issue for r epa i r , 1

In g rowing skull f ractures associa ted wi th

ra ised I C P , s h u n t surgery shou ld be con ­

s idered as an initial or al ternative p r o c e d u r e ,

as i t m a y resul t in reso lu t ion of ra ised I C P ,

d i sappea rance of scalp swellings a n d regrowth

of b o n e edges a t t he fracture s i t e ; 1 3 as illus­

t ra ted by case 3.

R e c u r r e n c e after surgical repair in two of

o u r pa t ien ts and o the r r epor ted c a s e s 1 3 co r re ­

lated with failure to secure water t igh t du ra l

c losure or failure to address the raised I C P .

Because of the k n o w n risk of fracture

g rowth a long wi th t he f requent ly progressive

n a t u r e o f b ra in d a m a g e a n d neurological

deficits, ch i ldren with l inear skull fractures

shou ld be examined clinically 2 - 3 m o n t h s

later to check for ev idence of growing fracture .

If a scalp bu lge or gaping b o n e defect is found ,

rad iography and C T shou ld b e repea ted . I f

g rowing skull fracture is conf i rmed, surgical

repair should be advised.

Address for correspondence: Professor N a i m - U r -

R a h m a n , Divis ion of N e u r o s u r g e r y , Col lege of

M e d i c i n e , K i n g S a u d Univers i ty & K i n g

K h a l i d Univers i ty Hosp i t a l , P O B o x 2 9 2 5 ,

Riyadh 1 1 4 6 1 , Saudi Arabia .

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