The imaging features of family aggregative ossification of posterior longitudinal ligament of cervical spine

English Keywords:Cervical spine  Ossification of posterior longitudinal ligament  Familial aggregation  Imaging features

English Abstract:

  【Abstract】 Objectives: To explore the imaging data of family ossification of the posterior longitudinal ligament(OPLL) in cervical spine and the genetic model of the family aggregation of the ossification of posterior longitudinal ligament. Methods: From January 2011 to February 2016, five pedigrees of family aggregation of the OPLL in cervical spine in the hospitalized patients were screened out, in which the proband had been diagnosed as the ossification of posterior longitudinal ligament of cervical spine by inquiring family history. Each member of the pedigrees was asked to take X-ray of cervical spine or computed tomography(CT) of cervical spine to observe the presence of OPLL or not. In this paper, the imaging findings of OPLL in cervical spine were defined as imaging positive findings. Results: (1)A total of 49 cases from five families, of which 17 were positive imagings. The overall positive rate was 35% (17/49). The positive rate of each family was between 17%-57%. (2)The imaging positive rate of male was 36% and of female was 33%, which showed no significant gender difference. (3)The cervical OPLL was found to mainly occur in the C4-C6 segment, with the highest incidence of C6(21%)，and in descending trend to the above and below. (4)The proportion of isolated type, segmental type, continuous type and mixed type was 4∶3∶3∶7. The mixed type accounted for a higher proportion. (5)The average age of each type was as following: isolated type was with 38 years old, segmental type was with 52 years old, continuous type was with 54 years old and mixed type was with 57 years old, in which all the positive members in third generation were isolated type. The average age of male was 49.5 years old; the average age of female was 52.3 years old. (6)C5 and C6 segments had the lowest average age of members over 40 years old with the ossification of posterior longitudinal ligament, and in increasing trend to the above and below. Conclusions: The imaging positive rate of cervical OPLL is higher in family members, and the imaging positive rate is not gender related. The classification of cervical OPLL is mainly mixed type. The cervical OPLL probably firstly occurs in C5 segment or C6 segment, isolated type and in the third generation members. The OPLL in male progresses rapidly.