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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