Investigation of ossification in the posterior longitudinal ligament using micro-focus X-ray CT scanning and histological examination

Diagnostic Pathology

Akihito Wada³  Kazutoshi Shibuya²  Tetsuo Nemoto¹  Megumi Wakayama¹  Naobumi Tochigi¹  Minoru Shinozaki¹  Yoichiro Okubo¹  Kazuaki Tsuchiya³  Hiroshi Takahashi³  Takao Ishiwatari¹  Katsunori Fukutake³ 

[1] Department of Surgical Pathology, Toho University School of Medicine, 6-11-1, Omori-Nishi, Ota-Ku, Tokyo 143-8541, Japan;Department of Dermatology, Peking University First Hospital, Beijing, China;Department of Orthopedic Surgery, Toho University Omori Medical Center, 6-11-1, Omori-Nishi, Ota-Ku, Tokyo 143-8541, Japan

关键词: Mechanisms of ossification;    Micro-focus X-ray CT;    Ossification of the posterior longitudinal ligament;   

Others  :  1233577
DOI  :  10.1186/s13000-015-0440-8

 received in 2015-09-25, accepted in 2015-11-12,  发布年份 2015

【 摘 要 】

Background

Ossification in the posterior longitudinal ligament (PLL) correlates with changes of enthesis during the early stages of development, but this issue remains controversial, as little is known regarding the details of this process. The aim of the present study was to elucidate part of the ossification mechanism. Thus, in the present study, we observed and evaluated minute ossifications in the PLL that did not exhibit symptoms of ossification of the posterior longitudinal ligament (OPLL).

Methods

The subjects in the present study were derived from serial autopsy cases from January 2009 to December 2013 at Toho University Omori Medical Center, Japan. Minute ossifications in the PLL from autopsy subjects without any history of OPLL were screened as high-density areas using micro-focus X-ray CT, and the foci were histologically examined. Subsequently, we conducted both micro-focus X-ray CT image analysis and histological examination, and evaluated the correlation between these findings and putative predictive factors reported in previous studies.

Results

A total of 103 individuals among the 267 subjects involved in the present study were analyzed within the study period. There were no cases involving OPLL identification prior to death, and no subjects presented with neurological symptoms of myelopathy. The incidence of cases involving high-density areas greater than 0.1 mm ²in the PLL was 46.6 %, half of which revealed mature bone structures inside this area. Thus, the high-density areas comprised three types: a continuous posterior-annular fibrosus type (23 cases), an isolated posterior-annular fibrosus type (11 cases), and a posterior-vertebral type (29 cases). However, a positive correlation was observed between the proportion of high-density areas, age (Pearson r = 0.265, p < 0.01), and HbA1c (Pearson r = 0.294, p < 0.01). Histological examination confirmed that these high-density areas involved calcification with or without mature bone formation.

Conclusions

We evaluated minute foci of calcification with and without ossification in the PLL from 103 cadavers, generating the following observations:

1. Minute calcification foci greater than 0.1 mm ²were observed in the PLL of 48 cases (46.6 %), half of which revealed mature bone structures inside this area (23.3 %).

2. The proportion of minute calcification foci observed in the present study was correlated with age and glucose tolerance, suggesting changes in the OPLL in the early stage.

3. Three different mechanisms of ossification were suggested: The two structures developed behind the disc might reflect the elongation of enthesis or rupture of annular fibrosus, while the remaining structure developed behind the vertebral body might reflect a dystrophic calcification-based bony metaplasia sequence.

【 授权许可】

   
2015 Fukutake et al.

【 图 表 】

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