Clinical characterizations and radiologic findings of pure foraminal-type cervical disc herniation: CT discography as a useful adjuvant in its precise diagnosis.

Abstract

A retrospective study of 15 cases of pure foraminal type cervical disc herniation (CDH) was performed. The objectives were to describe the clinical characteristics and to assess the radiologic findings. Although foraminal lumbar disc herniation has been reported, pure foraminal-type CDH has not been fully elucidated. It is not only a rare condition but also a difficult one to diagnose. All patients underwent MRI, CT myelography (CTM), and CT discography (CTD). Herniated discs were removed by the posterior approach. Clinical symptoms were evaluated at preoperative and postoperative period. On MRI, 2 cases were positive, 6 cases were suspected, and 7 cases were negative. On CTM, 7 cases were positive and 8 cases were negative; and on CTD, all cases were positive. As to the association between the herniated disc and posterior longitudinal ligament, 12 cases were intraligamentous. The association between the herniated disc and nerve root revealed that 10 discs were at the axillary portion of the nerve root. Pure foraminal-type CDH may be overlooked with conventional MRI or CTM, so CTD should be performed. It provides valuable and additional information in difficult or ambiguous cases such as pure foraminal type.