Developmental Pattern of the Posterior Osteophyte in Cervical Disk Disease—An Intraoperative, Histopathological Study

Abstract

Introduction In cervical disk disease, a corroborative study of the intraoperative findings as observed under operating microscope within each disk space level has not been correlated with the histopathological characteristics. Our aim is to find out the developmental pattern of the posterior osteophyte in each cervical intervertebral disk space and the stages through which the posterior osteophyte is formed. This type of study has not been documented in literature. Materials and Methods 1st Phase: In a prospective study conducted over first 3 years (2007 to 2009), intraoperative observations of 259 disk spaces in 179 patients who were operated for cervical disk disease using the standard anterior cervical microdiscectomy were analyzed. We observed under operating microscope 29 C3-C4 disc spaces, 54 C4-C5, 106 C5-C6, 67 C6-C7, 2 C7-D1, and 1 C2-C3 disk space during the study period. 2nd Phase: The above prospective study was extended into the second phase over next 3 years (2009 to 2011), and clinico-radiological (MRI findings)-intraoperative observations of 116 disk spaces in 67 patients who were operated for cervical disc disease were analyzed. These observations were correlated with the histopathological characteristics of the excised disk material. Results 1st Phase study: At C3-C4 disk space, posterior osteophyte originates from the upper vertebral body C3 (75.8%). In mobile segments of C4-C5 (74.1%) and C5-C6 (83.9%) disk spaces, the osteophyte arises in most of the cases from posterior margins of both the vertebral bodies. At C6-C7, it arises from lower vertebral body C7 (71.7%). 2nd Phase: We observed histopathologically and intraoperatively, that posterior osteophytes formation goes through three stages. Posterior osteophyte formation is of fibrocartilage in 8.6% (10/116), mixed variety in 10.3% (12/116), and Bony type in 81.1% (94/116). In patients who had Bony type, 89.4% had myelopathy, 75.8% had radiculopathy whereas 90.4% patients had hyperintense signal within the spinal cord. Conclusion Our results show that there is a definite pattern in the formation of the posterior osteophyte within the cervical disk spaces. At junctional areas like C3-C4 and C6-C7, the posterior osteophyte originates from the relatively fixed vertebra like C3 and C7. In mobile segments like C4-C5 and C5-C6, the posterior osteophyte originates from both the bodies of adjacent vertebra. We also observed that the posterior osteophyte formation in cervical disk disease goes through the following three stages: 1st stage: Fibrocartilage, 2nd stage: Mixed type consisting of both the fibrocartilage and partially bony and 3rd stage: Bony type. These stages we feel evolve over a span of few years. Patients presenting with myeloradiculopathy and hyperintense signal within the spinal cord are likely to harbor bony posterior osteophytes compressing the thecal sac and requires surgical intervention. This is the first document of its kind in the literature. I confirm having declared any potential conflict of interest for all authors listed on this abstract No Disclosure of Interest None declared