Congenital variations of the upper cervical spine and their importance in preoperative diagnosis. A case report and a review of the literature

Abstract

Several variations of the bony and vascular anatomy around the first and second cervical vertebrae have been reported. Failure to recognise these variations can complicate operations on the upper cervical spine. We present a patient with recent onset of cervical myelopathy due to stenosis at the C3-4 level. Preoperative evaluation identified Klippel-Feil syndrome with cervical fusion of C2-3, aplasia of posterior arch of C1, anomalous vertebral artery course and a "ponticulus posticus" of C2. The combination of these variations in a Klippel-Feil syndrome patient has never been reported. Thus, we recommend a thorough preoperative imaging evaluation, with CT scan and CT angiography or DSA, in addition to plain radiographs. This evaluation is imperative, before a cervical spine surgery, allowing a better understanding of the anatomy, in order to minimise the risks of misplacement of cervical instrumentation especially in such patients.

Craniovertebral anomalies associated with pituitary gland duplication

“…These congenital fusions of the cervical vertebrae are consistent with the Klippel-Feil anomaly, Rubinstein-Taybi syndrome and some other disorders [16,21,28,30,40,55].…”

“…In some cases, a cleft of another cervical vertebra was seen, as well as a duplication of the cervical vertebral bodies. In other patients, partial or complete fusion affected various cervical vertebrae: C2-C3, C3-C5 or C2-C5 [28,40,45]. In 1 patient thoracolumbo-sacral rachischisis was reported [36].…”

“…As regards the atlas, its agenesis, partial aplasia, hypoplasia or a cleft of the C1 posterior arch can appear, or the agenesis or aplasia of the anterior arch [1,2,6,8,9,24,27,28,35,36,38,51]. Occurrence of the supernumerary facets of the atlas is also possible, as well as its partial fusion with the odontoid or with the anterior rim of the foramen magnum, or an incomplete transverse foramen [18,25,39,46].…”

“…Certain changes in the region of the odontoid process may also occur: its aplasia [1,19], hypoplasia [10,12,48,54,55], fusion with the C1 anterior arch or with the clivus [18], as well as cleft, bifurcation [43] or duplication [15,30]. Occasionally, basilar invagination occurs, or os odontoideum or os terminale close to the dens [1,3,12,13,17,28,46,55].…”

The feasibility of inserting a C1 pedicle screw in patients with ponticulus posticus: a retrospective analysis of eleven patients

“…This bony bridge has been called by different names, but ponticulus posticus is currently the most commonly used term [1][2][3][4][5][6][7][8]. LampropoulouAdamidou et al reported a ''ponticulus posticus'' of axis [9]. Actually, it is not a real ''ponticulus posticus'', because ''ponticulus posticus'' is usually known as an abnormal bony arch of atlas.…”