Congenital Osseous Anomalies of the Cervical Spine: Occurrence, Morphological Characteristics, Embryological Basis and Clinical Significance: A Computed Tomography Based Study.

Study Design: Observational retrospective computed tomography (CT) based study.

Purpose: To analyze the congenital anomalies of the cervical spine, their morphological variations and their clinical significance.

Overview of Literature: Studies published to date have focused mainly on upper cervical anomalies; no study has comprehensively reported on anomalies of both the occipitocervical and subaxial cervical spine.

Methods: Nine hundred and thirty cervical spine CT scans performed in Ganga Hospital, Coimbatore, India between January 2014 and November 2017 were screened by two independent observers to document anomalies of both the upper and lower cervical spine. CT scans conducted for infection, tumor, and/or deformity were excluded. Different morphological variations, embryological basis, and clinical significance of the anomalies were discussed.

Results: Of the 930 CT scans screened, 308 (33.1%) had congenital anomaly. Of these, 184 (59.7%) were males and 124 (40.2.7%) were females, with a mean age of 44.2 years (range, 14-78 years). A total of 377 anomalies were identified, with 69 cases (7.4%) having more than one anomaly. Two hundred and fifty (26.8%) anomalies of the upper cervical region (occiput to C2-C3 disk space) were identified, with the most common upper cervical anomalies being high-riding vertebral artery (108 cases, 11.6%) and ponticulus posticus (PP) (75 cases, 8%). One hundred and twenty seven (13.6%) anomalies of the lower cervical spine (C3-C7) were noted, of which double foramen transversarium was the most common anomaly observed in 46 cases (4.8%).

Conclusions: We found that 33.1% of CT scans had at least one congenital anomaly. Some anomalies, such as abnormal facet complex and arch anomalies, have to be differentiated from fractures in a trauma patient. Other anomalies, like PP, have to be looked for during preoperative planning to avoid complications during surgery. Therefore, knowledge of these anomalies is important as different anomalies have different clinical courses and management.