Static versus dynamic factors for the development of myelopathy in patients with cervical ossification of the posterior longitudinal ligament.
We studied 27 patients with cervical ossification of the posterior longitudinal ligament (OPLL) but no clinical symptoms of myelopathy. We investigated the occupation ratio of the spinal canal by OPLL with cervical radiographs, assessed the morphological types of OPLL, and measured the segmental range of motion (ROM) at the level of maximum cord compression on flexion and extension radiographs. Patients were classified as having continuous-type OPLL (17 patients), mixed-type OPLL (seven patients), or segmental-type OPLL (three patients). The segmental ROM was negatively correlated with the OPLL occupation ratio (r=-0.49, p<0.01). No patient developed myelopathy during the study period. Three patients with massive OPLL did not develop myelopathy and the mobility of their cervical spine was highly restricted, suggesting that dynamic factors such as the segmental ROM preferentially contribute to the development of myelopathy in patients with cervical OPLL. Thus, by controlling the dynamic factors (hypermobility), we might be able to reduce neurological deterioration in patients with cervical OPLL.
Fujiyoshi
Takayuki
T
Spine Section, Department of Orthopaedic Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8677, Japan.
Yamazaki
Masashi
M
Okawa
Akihiko
A
Kawabe
Junko
J
Hayashi
Koichi
K
Endo
Tomonori
T
Furuya
Takeo
T
Koda
Masao
M
Takahashi
Kazuhisa
K
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000150:complications* / Q000000981:diagnostic imaging; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging / Q000209:etiology; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D001745:Urinary Bladder Diseases / Q000209:etiology