] 979, British Journal of Radiology, 52, 865-869
NOVMEBER 1 979
Ossification of the posterior longitudinal ligament of the spine By W. S. Chin, M.D., D.M.R.D., F.R.C.R. Department of Diagnostic Radiology, Singapore General Hospital, Outram Road, Singapore 3
and C. L Oon, M.B., B.S., D.M.R.D., F.R.C.R. X-ray Clinic, Singapore Medical Centre, Singapore 10 (Received November 1978 and in revised form April 1979)
ABSTRACT
"The Japanese disease" or ossification of the posterior longitudinal ligament of the cervical spine was initially thought to affect only the Japanese people. Non-Japanese Asian and Caucasian cases have been reported but appear to be exceedingly rare. The reason is unknown. Although the disease appears to be generally benign, it can cause a myelopathy. We present here 16 non-Japanese patients in Singapore who were found to have ossification of the posterior longitudinal ligament in the cervical, thoracic and lumbar spine.
In 1960, Tsukimoto presented an autopsy report of a 47-year-old man with progressive myelopathy caused by an ossified posterior longitudinal ligament extending from the third to the fourth cervical vertebra. This account was soon followed by several other Japanese reports of ossification of the posterior longitudinal ligament of the cervical spine in Japanese patients. These individuals were either asymptomatic or had symptoms of cervical spondylosis. A few presented with a cervical myelopathy. Terayama et al. (1964), introduced the term "ossification of the posterior longitudinal ligament of the cervical spine" to differentiate this condition from ankylosing spondylitis, senile ankylosing hyperostosis (Forestier and Rotes Querol's disease) and spondylosis of the spine. Autopsy and biopsy reports confirm the pathological change to range from unorganized calcification to true bone formation (Furuya et al., 1968; Onyi et al., 1967; Palacios et ah, 1971). Ossification in the thoracic and lumbar regions was also found but is much less common. The disease appeared to be confined to the Japanese until 1969 when Minagi and Gronner (1969) reported the first two Caucasian cases in the United States. Further reports added another ten Caucasian and one Negro patient (Bakay et al., 1970; Breidahl, 1969; Forcer and Horsey, 1970; Palacios et al., 1971). The only report of non-Japanese Asians affected with this disease came from Soo and Sachdev (1971) who described two patients from Malaysia. We present here 16 non-Japanese Asians from Singapore with ossification of the posterior longitudinal ligament in the cervical, thoracic and lumbar spine. 865
PATIENTS
There were 16 patients with ossification of the posterior longitudinal ligament, with equal sex incidence. Their ages ranged from 45 to 79 years. Ten were Chinese, four Indian and two Malay. Singapore's ethnic distribution is 76% Chinese, 15% Malay, 7% Indian and 2% of mixed origin.
FIG. 1. Case 10. Typical example of marked ossification of the posterior longitudinal ligament of the cervical spine extending uninterruptedly from C2 to C4.
VOL.
52, No. 623 W. C. Chin and C. L. Oon
FIG. 2. ±
NOVMEBER 1 979
Ossification of the posterior longitudinal ligament of the spine By W. S. Chin, M.D., D.M.R.D., F.R.C.R. Department of Diagnostic Radiology, Singapore General Hospital, Outram Road, Singapore 3
and C. L Oon, M.B., B.S., D.M.R.D., F.R.C.R. X-ray Clinic, Singapore Medical Centre, Singapore 10 (Received November 1978 and in revised form April 1979)
ABSTRACT
"The Japanese disease" or ossification of the posterior longitudinal ligament of the cervical spine was initially thought to affect only the Japanese people. Non-Japanese Asian and Caucasian cases have been reported but appear to be exceedingly rare. The reason is unknown. Although the disease appears to be generally benign, it can cause a myelopathy. We present here 16 non-Japanese patients in Singapore who were found to have ossification of the posterior longitudinal ligament in the cervical, thoracic and lumbar spine.
In 1960, Tsukimoto presented an autopsy report of a 47-year-old man with progressive myelopathy caused by an ossified posterior longitudinal ligament extending from the third to the fourth cervical vertebra. This account was soon followed by several other Japanese reports of ossification of the posterior longitudinal ligament of the cervical spine in Japanese patients. These individuals were either asymptomatic or had symptoms of cervical spondylosis. A few presented with a cervical myelopathy. Terayama et al. (1964), introduced the term "ossification of the posterior longitudinal ligament of the cervical spine" to differentiate this condition from ankylosing spondylitis, senile ankylosing hyperostosis (Forestier and Rotes Querol's disease) and spondylosis of the spine. Autopsy and biopsy reports confirm the pathological change to range from unorganized calcification to true bone formation (Furuya et al., 1968; Onyi et al., 1967; Palacios et ah, 1971). Ossification in the thoracic and lumbar regions was also found but is much less common. The disease appeared to be confined to the Japanese until 1969 when Minagi and Gronner (1969) reported the first two Caucasian cases in the United States. Further reports added another ten Caucasian and one Negro patient (Bakay et al., 1970; Breidahl, 1969; Forcer and Horsey, 1970; Palacios et al., 1971). The only report of non-Japanese Asians affected with this disease came from Soo and Sachdev (1971) who described two patients from Malaysia. We present here 16 non-Japanese Asians from Singapore with ossification of the posterior longitudinal ligament in the cervical, thoracic and lumbar spine. 865
PATIENTS
There were 16 patients with ossification of the posterior longitudinal ligament, with equal sex incidence. Their ages ranged from 45 to 79 years. Ten were Chinese, four Indian and two Malay. Singapore's ethnic distribution is 76% Chinese, 15% Malay, 7% Indian and 2% of mixed origin.
FIG. 1. Case 10. Typical example of marked ossification of the posterior longitudinal ligament of the cervical spine extending uninterruptedly from C2 to C4.
VOL.
52, No. 623 W. C. Chin and C. L. Oon
FIG. 2. ±
