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Ossification of the posterior longitudinal spinal ligament in association with anterior longitudinal ligament ankylosing hyperostosis: report of two cases.

Ossification of the posterior longitudinal ligament (OPLL) has been frequently reported in Japanese literature, but few cases have been documented in Taiwan.
Two cases of OPLL combined with anterior ankylosing hyperostosis are the focus of this report. Case 1 was a 38 year-old male who reported upper limbs numbness and weakness occurring over 2 years. Later his symptoms progressed and involved all four extremities which resulted in walk with a spastic gait, CT scan showed a mixed type of OPLL. Case 2 was a 50 year-old male who had a sudden onset of left thumb and index finger numbness, and subsequent right lower limb numbness. After an accidental fall, the symptoms became worse. Again CT scan disclosed a tandem type OPLL＞ Both cases achieved satisfactory improvement after a bilateral C3 to C6 laminectomy. A high resolution CT scan proved extremely valuable in the diagnosis of OPLL, not only for indentifying the location of OPLL, but also in determining the shape and severity of it.