Cervical Spine Anomalies in the Craniosynostosis

Syndromes

KAYE M. Hemmer, M.D.

WILLIAM H. McAListER, M.D.

JEFFREY L. MARSH, M.D.

Cervical spine radiographs of 34 patients with a variety ofcraniosynostosis syndromes were reviewed to determine the incidenceand nature of skeletal anomalies and to evaluate the findings in terms

of syndromal patterns. Intervertebral fusions occurred in 30 percent ofPfeiffer's, 38 percent of Crouzon's, and 71 percent of Apert's syndromechildren. In Crouzon's and Pfeiffer's syndromes, isolated upper cervi-

cal fusions were most common; in Apert's syndrome, the fusions weremore likely to be complex involving C5-C6. This syndromal variation,however, was not specific enough for diagnostic differentiation.

Elucidating the full spectrum of a disease

process assists diagnosis, prognosis, and treat-

ment. Such elucidation also may assist compre-

hension of the etiology and underlying

pathophysiology of the process. Skeletal anoma-

lies are recognized concomitants of the various

craniosynostosis syndromes (Gorlin et al, 1976).

Acral anomalies have been focused upon, aside

from the skull findings, to assist syndrome

differentiation among affected patients. While

axial skeletal anomalies have been described in

patients with these syndromes, they have not

been documented in detailed fashion in the liter-

ature. Kreiborg (1981), in his monograph on

Crouzon's syndrome, reported a variety of cer-

vical spine findings affecting one-third of that

population. The most common finding was iso-

lated intervertebral fusion involving the C2-C3

interspace. Kreiborg (1987) subsequently report-

ed a survey of the cervical spines of his patients

with Apert's syndrome. Two-thirds of the

Apert's syndrome patients displayed cervical

spine abnormalities with predominance of fusions

at the C5S-C6 interspace. In contrast to the sim-

ple fusions found in Crouzon's, fusions in

Apert's syndrome patients were generally com-

plex or involved more than an isolated inter-

All of the authors are affiliated with the WashingtonUniversity Medical Center, St. Louis, MO. Dr. Hemmer isa Fellow in Craniofacial Surgery Division of Plastic andReconstructive Surgery. Dr. McAlister is Professor of Radi-ology, Mallinckrodt Institute of Radiology, and Head of Pedi-atric Radiology at Children's Hospital. Dr. Marsh is Professorof Surgery, Plastic and Reconstructive, and Medical Direc-tor of Cleft Palate and Craniofacial Deformities Institute, atChildren's Hospital.

328

space. Although variation in the nature and

distribution of cervical spine anomalies was not-

ed between Kreiborg's two syndrome groups, the

findings were not specific enough to allow syn-

drome differentiation. We, therefore, undertook

a retrospective study of our patients with

craniofacial dysostosis syndromes to ascertain the

nature and frequencies of cervical spine defor-

mities and to determine whether diagnostically

useful syndromal variations were present.

METHOD

The charts of all patients with craniosynosto-

sis syndromes followed in the Cleft Palate and

Craniofacial Deformities Institute of Washing-

ton University Medical Center, St. Louis, Mis-

souri, were reviewed to verifty the authenticity

of the diagnoses utilizing description of craniofa-

cial and acral anomalies and genetic evaluation.

Patients diagnosed as "upper Crouzon'"' or bi-

coronal synostosis without evidence of maxillary

retrusion were excluded. The radiographic cer-

vical spine images available for the remaining

patients with the various craniosynostoses syn-

dromes were reviewed without knowledge of the

diagnoses by a single pediatric radiologist. All

available images of the cervical spine were used

in the review. These included standard frontal

and lateral spine projections as well as addition-

al views of the cervical spine as seen on skull

and chest radiographs and cephalometrograms.

Some abnormalities, especially fusions, were

noted only on subsequent spine radiographs and

not on earlier ones. In such cases, the later ob-

servations were those recorded.

Hemmer et al, CERVICAL SPINE ANOMALIES IN CRANIOSYNOSTOSIS SYNDROME 329

RESULTS

The study population consisted of 34 patients.

The syndromal diagnoses were: 16 Crouzon's, -

7 Apert's, 7 Pfeiffer's, 3 Carpenter's, and 1

Saethre-Chotzen syndrome. There were 19 males

and 15 females. The age at the time cervical

spine films were obtained ranged from birth to

20 years, with a median age of 9 years.

Four types of cervical spine abnormalities

were encountered: fusions (N= 20), high atlas

(N=9), butterfly vertebrae (N=2), and over-

sized odontoid (N= 1). Fusions included facet

fusions, neural arc fusions, and block vertebrae.

'*Neural arch fusions'' (N= 6) referred to more

complex fusions than those just involving the

facet joints (N=7). ''Block vertebra'' (N=7)

was used to describe partial or complete fusion,

either cartilaginous or bony, of two or more ver-

tebrae. '"'High atlas" referred to an atlas that was

close to but not fused with the occiput. The dis-

tribution of the specific cervical anomalies

among the craniosynostosis syndromes was not

syndrome specific (Table 1). Nonetheless, pa-

tients with Crouzon's and Apert's syndromes had

the highest proportion of anomalies. Specifical-

ly, facet fusion occurred in three of 16 Crouzon's

and three of seven Apert's syndrome patients

(Figs. 1 and 2). Block vertebrae were found in

two Crouzon's, three Apert's, and two Pfeiffer's

syndrome patients (Figs. 1B and 2B). Neural

arch fusion was noted in two patients each of

Crouzon's, Apert's and Pfeiffer's syndromes.

The majority of high atlas occurred in Crouzon's

syndrome patients (Fig. 1B). Butterfly vertebae

were ecountered in two Crouzon's syndrome pa-

tients (Fig. 3). There was an incidental finding

of an oversized odontoid in one of three patients

with Carpenter's syndrome. There were no ab-

normalities noted in the one child with Saethre-

Chotzen syndrome.

Cervical spine fusions were more common in

Apert's syndrome (71 percent) than in Crouzon's

syndrome (38 percent) patients (Table 2).

Although the anatomic distribution of fusions

was not syndrome specific, some trends were ob-

served. There was involvement of an isolated in-

terspace in five of six affected Crouzon's

syndrome, versus two of five affected Apert's

syndrome patients. Furthermore, the majority of

fusions in the Apert's group were complex, span-

ning more than a single interspace. Four of six

fusions in Crouzon's syndrome patients involved

C2-C3; this interspace was not involved in any

Apert's syndrome patients. All but one Apert's

syndrome fusion included the C5-C6 interspace.

Two Crouzon's syndrome spines had isolated in-

volvement of this interspace, and a third showed

inclusion of the C5-C6 interspace in a complex

fusion involving the entire cervical column.

DISCUSSION

A variety of skeletal anomalies have been iden-

tified in the cervical spine of patients with

craniosynostosis syndromes (Uhlmann, 1952;

Pruzansky, 1976; Kreiborg, 1981, 1987). The

most frequently identified abnormality was in-

tervertebral fusion, obliterating part or all of the

involved intervertebral space, facets, or re-

mainder of the neural arch (Kreiborg, 1981).

Although such fusion may be seen in the gener-

al population at large, such malformations are

infrequent (Resnick, 1981). In a review of 700

spines from patients in an orthopaedic hospital,

the incidence of cervical fusions was 0.5 percent

(Shands, 1956). Cervical fusions were detected

in 2.9 percent of 105 patients with cleft lip with

or without cleft palate (Sandham, 1986). In con-

trast, the frequency of fusions was 32 percent

in Kreiborg's Crouzon's syndrome population

(N= 47), 38 percent in our Crouzon's syndrome

set (N=16); and 67 percent in Kreiborg's

Apert's syndrome population (N= 36), 71 per-

cent in our Apert's syndrome set (N=7). This

markedly increased frequency presumably

reflects a pathophysiologic process that distin-

guishes the craniosynostosis syndromes from the

general population. Nonetheless, the nature of

the cervical spine abnormalities observed in these

TABLE 1 Specific Cervical Spine Findings in the Various Craniosynostosis Syndromes

Syndromes

CervicalSpinejie Crouzon'sFindings (N= 16)

Apert's

(N=7)Saethre-Chotzen's

(N=1)

Pfeiffer's

(N=7)

Carpenter's

(N=3)

Facet fusionBlock vertebraeNeural arch fusionHigh atlasButterfly vertebraeLarge odontoid JOD

JODDQ

OC-

bQ

GQ

JO3ND

NJO

-&&OOO

&&OOO-

330 Cleft Palate Journal, October 1987, Vol. 24 No. 4

FIGURE 1 Crouzon's syndrome. A, Girl, age 10 years, facet fusion of C2-C3 (ar-row). B, Girl, age 12 years, showing a high atlas, block vertebra (arrowhead) withneural arch fusion of C2-C3 (arrow).

Hemmer et al, CERVICAL SPINE ANOMALIES IN CRANIOSYNOSTOSIS SYNDROME 331

FIGURE 2 Apert's syndrome. A, Boy, age 11 years, with facet fusion of C5-C6 (arrow). B, Boyblock vertebra of CS-C6 (arrow).

age 8 years, with

FIGURE 3 Crouzon's syndrome. Four-month-old boy with butterfly vertebra of C6 and C7 (arrows).

332 Cleft Palate Journal, October 1987, Vol. 24 No. 4

TABLE 2 Cervical Spine Fusions in Crouzon's VersusApert's Syndrome .

Cervical Crouzon's Apert's

Spine Syndrome Syndrome

Fusion (N=16) (N= 7)

C2-3 3 0C4-5 0 1C5S-6 2 1C3-4, 5-6 0 1C4-5, 5-6 0 1C5S-6, 6-7 0 1C2 thru 7 1 0No fusions 10 2

syndromes are not specific and can be seen in

a number of other conditions (Taybi, 1983).

The cranial and facial anomalies in Crouzon's

and Apert's syndromes, while having many fea-

tures in common, are sufficiently distinct, in

most cases, to allow separation of the two con-

ditions on the basis of craniofacial features

without reference to their acral deformities.

While the most frequent cervical spine abnormal-

ity identified in both groups was intervertebral

fusion, there were distinct differences between

the two syndromes in the frequency, location,

and complexity of these fusions. Fusion in the

Crouzon's syndrome group occurred only half

as frequently as in the Apert's syndrome group.

Although the C2-C3 interspace was involved in

over half of the Crouzon's syndrome patients,

this interspace was never involved in those with

Apert's syndrome. Conversely, C5S-C6 was

fused in two-thirds of the Apert's syndrome

cases, but in the Crouzon's syndrome popula-

tion it was involved half of the time. Although

our sample is small, the findings do coincide with

Kreiborg's (1981, 1987) finding of a

predominance of C5S-C6 involvement in Apert's

syndrome, in contrast to predominance of C2-C3

involvement in Crouzon's syndrome. Further-

more, the majority of the Crouzon's syndrome

fusions involved an isolated interspace, but the

Apert fusions were generally more complex, in-

volving more than one interspace both in our

populations and Kreiborg's. High atlas was

found primarily in our Crouzon's syndrome

population. The reasons for the distinct anatom-

ical regions and degrees of fusions in Crouzon's

versus Apert's syndromes are unknown. There

may be fundamental differences in the underly-

ing osseous pathophysiology, which accounts for

the variations in acral anomalies as well. Crou-

zon's and Pfeiffer's syndromes tend to be essen-

tially indistinguishable on the basis of

craniofacial features alone. Their similarity also

is reflected in the cervical spines of the two con-

ditions. Our patients couldnot be sorted by syn-

drome according to cervical spine anomalies.

Conclusions cannot bedrawn from our single

case of Saethre-Chotzen syndrome.

The cervical fusions in the craniosynostosis

syndromes have been shown to be progressive

with aging (Schauerte and St.-Aubin, 1966; Kaye

et al, 1978; Pruzansky, 1976). The age of the

study population, therefore, can affect incidence

and distribution of data. The younger the sam-

ple, the greater the chance of underestimation of

the spine anomalies. The median age of our pa-

tients, 9 years, is younger than that of

Kreiborg's, the majority of whom were adoles-

cents or adults.

What are the clinical implications of these find-

ings? Although there are variations in the cervi-

cal spine anomalies among the various

craniosynostosis syndromes, there is insufficient

syndrome specificity for this information to be

used diagnostically. Although the observed fu-

sions do not limit significantly the range of clin-

ical cervical motion, the restricted flexion

extension may affect placement of an endo-

tracheal tube. It is important to recognize such

cervical anomalies prior to the induction of

anesthesia since they may compound the already

problematic airway management of these pa-

tients. We did not find odontoid disorders in our

population, as did Kreiborg (1981), which might

allow a fatal C1-C2 subluxation. The possibility

of this occurrence, however, has been discussed

by others (Munro, 1986).

CONCLUSIONS

Cervical spine anomalies can be documented

radiographically in patients with a variety of

craniosynostosis syndromes. Intervertebral fu-

sions occurred in 30 percent of Pfeiffer's, 38 per-

cent of Crouzon's, and 71 percent of Apert's

syndrome children. In Crouzon's and Pfeiffer's

syndromes, isolated upper cervical fusions were

most common; in Apert's syndrome, the fusions

were more likely to be complex involving

C5S-C6. These differences in fusion site and na-

ture may reflect differences in underlying osse-

ous pathophysiology. This syndromal variation,

however, was not specific enough for diagnos-

tic differentiation. The limitation of cervical

range of motion resultant from these anomalies

may have clinical significance with respect to

surgical airway management in these patients.

Acknowledgment. We are indebted to Ms. Karen Lask for

manuscript preparation.

Hemmer et al, CERVICAL SPINE ANOMALIES IN CRANIOSYNOSTOSIS SYNDROME 333

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