Hypoplasia of C-1 in children with Down syndrome

Congenital defect of the posterior arch of C1: a case report

Odontoid fractures are one of the most common injuries to the cervical spine in geriatric patients. Congenital C1 arch absence, however, is a very rare anomaly found in the population. We describe the first reported case of a congenital C1 posterior arch absence and C1 anterior cleft presenting with odontoid fracture. We present the case of a 58-year-old male who was found to have a comminuted type III odontoid fracture with significant angulation and displacement. CT scan demonstrated this fracture and also demonstrated congenital cleft of his left anterior arch and absence of left C1 posterior arch. Given his anatomic anomaly, we elected to perform occipitocervical fusion. The patient underwent occipito-cervical fusion to avoid iatrogenic vertebral artery injury. He was also immobilized in a halo vest given patient-specific social factors and compromised bone quality. The patient had no intra- or post-operative complications, but a prolonged hospital stay due to alcohol withdrawal. At 3-month postoperatively the patient had no neck pain and return to baseline function. This case highlights the importance of obtaining a CT scan preoperatively to not only to further characterize the fracture but also for surgical planning and recognition of anatomic anomalies as this may significantly impact the operative strategy.

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

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.