Cervical kyphosis: predictive factors for progression of kyphosis and myelopathy.
METHODS
A retrospective study of 13 patients with cervical kyphosis. The authors propose new methods of measuring spinal cord compression and predicting the progression of kyphosis.


OBJECTIVE
To ascertain predictive factors for progression of cervical kyphosis and myelopathy.


BACKGROUND
Cervical kyphosis may be congenital, result from decompression surgery, or occur as a posttraumatic deformity. Although there is the potential for progressive deformity and the development of myelopathy in all these situations, there are few previous reports of predictive factors for progression of cervical kyphosis and myelopathy in patients with cervical kyphosis.


METHODS
The authors studied radiographs and magnetic resonance imaging scans of 13 patients with cervical kyphosis, including 9 who had been operated on and had postsurgical secondary kyphosis, and 4 with idiopathic kyphosis without any of the above causes. Compression of the spinal cord at the apex of the cervical kyphosis was evaluated by magnetic resonance imaging of the ratio between the anteroposterior diameter of the medulla-pons junction and the spinal cord at the apex.


RESULTS
The mean ratio between the anteroposterior diameter of the medulla-pons junction and the spinal cord at the apex in five patients in whom myelopathy did not develop was 0.37, and was 0.21 in the patients in whom myelopathy developed. Progression of cervical kyphosis was associated with osteophyte formation at the anterior aspect of the vertebral body.


CONCLUSIONS
A ratio below 0.3 between the anteroposterior diameter of the medulla-pons junction and the spinal cord at the apex was a risk factor for cervical myelopathy. One of the most predictable risk factors of progression of the cervical kyphosis was osteophyte formation at the anterior aspect of the vertebral body.
Department of Orthopaedic Surgery, Osaka Rosai Hospital, Sakai, Japan. iwasaki@orh.go.jp
Motoki
M
Iwasaki
Tomio
T
Yamamoto
Akira
A
Miyauchi
Keiichi
K
Amano
Kazuo
K
Yonenobu
D000293:Adolescent; D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging; D002648:Child; D018450:Disease Progression; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D013117:Spinal Cord Compression / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D013128:Spinal Osteophytosis / Q000150:complications / Q000175:diagnosis