Cervical myelopathy due to OPLL: clinical evaluation by MRI and intraoperative spinal sonography.
BACKGROUND
Concerning the relationship between morphology and clinical outcome, there have been many reports using computed tomography/myelography but not so many using axial magnetic resonance imaging (MRI) of the spinal cord. This is the first report to correlate axial cord image, intensity changes in MRI, and cord expansion pattern using intraoperative ultrasonography.


OBJECTIVE
The objectives were to correlate MRI studies, axial cord images/expansion, and changes in MRI intensity to see if there is a direct prognostic significance to these changes and to determine whether preoperative axial MRI images of the spinal cord predict recovery from compressive myelopathy.


METHODS
Posterior cervical decompressions with laminoplasty were performed in 44 patients with cervical myelopathy due to ossification of the posterior longitudinal ligament. On T2-weighted MR images, the cross-sectional shape of the cord at the level of maximal compression was categorized as boomerang, teardrop, or triangle. Additionally, with use of intraoperative ultrasonography, the expansion pattern of the cord that occurred intraoperatively was contrasted with that seen on postoperative MR images.


RESULTS
Clinical recovery rates were the worst for those with triangular, intermediate for those with boomerang, and the best for those with teardrop shape. Preoperative low T1 and high T2 signals were found in most cases with triangular cord configurations. Triangular cord configurations showed the least expansion among the three categorized spinal cords.


CONCLUSIONS
Patients with triangular deformity of the cord have atrophy as confirmed on MR studies where there is a low T1 and high T2 signal in the cord. Poor postoperative clinical recovery correlates with the lack of postoperative cord expansion on either MR or ultrasound evaluations. Those with either teardrop or boomerang deformities demonstrate a relatively good recovery rate.
Matsuyama
Yukihiro
Y
Nagoya University School of Medicine, Nagoya, Japan. spine-yu@med.nagoya-u.ac.jp
Kawakami
Noriaki
N
Yanase
Makoto
M
Yoshihara
Hisatake
H
Ishiguro
Naoki
N
Kameyama
Takashi
T
Hashizume
Yoshio
Y
D000328:Adult; D000368:Aged; D015984:Causality; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D019299:Decompression, Surgical; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000639:trends; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods / Q000639:trends; D017887:Ossification of Posterior Longitudinal Ligament / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D013115:Spinal Canal / Q000000981:diagnostic imaging / Q000473:pathology; D013116:Spinal Cord / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D016896:Treatment Outcome; D014463:Ultrasonography / Q000379:methods / Q000639:trends