Is posterior spinal cord shifting by extensive posterior decompression clinically significant for multisegmental cervical spondylotic myelopathy?
METHODS
Posterior cervical spinal cord shifting after selective single laminectomy associated with partial laminotomies was compared with that after bilateral open-door laminoplasty between the C3 and C7 levels in relation to the clinical results of each procedure.


OBJECTIVE
To investigate the clinical significance of posterior spinal cord shifting after extensive cervical laminoplasty.


BACKGROUND
Current techniques used for cervical laminoplasty for multisegmental cervical spondylotic myelopathy (CSM) are consecutively performed between the C3 and C6 or C7 levels with expectation that the spinal cord will shift backward to keep it clear of anterior compression. However, the clinical significance of the posterior spinal cord shifting remains controversial, and there has been no report verifying it by comparing limited posterior decompression procedures with conventional extensive ones.


METHODS
Twenty-six patients with consecutive 2- to 3-level CSM who underwent selective laminoplasty (Group A) were enrolled in the study, and among 56 CSM patients who underwent bilateral open-door laminoplasty between the C3 and C7 levels, 25 who had consecutive 2- or 3- level stenosis identified by preoperative magnetic resonance imaging were used as controls (Group B). The recovery rate was calculated using preoperative and postoperative Japanese Orthopedic Association (JOA) scores for each patient, and for each patient's magnetic resonance imaging, the postoperative cervical curvature index was obtained according to Ishihara's method and the magnitude of postoperative backward shifting of the spinal cord was measured.


RESULTS
There was no significant difference between the subjects in Groups A and B with respect to the spinal curvature index, preoperative JOA scores, and recovery rate, but the magnitude of the postoperative posterior shifting of the spinal cord was greater for those in Group B than for those in Group A. There was no correlation between the recovery rate and posterior shifting of the spinal cord for each group, and no correlation was also found between the curvature index and posterior shifting of the spinal cord.


CONCLUSIONS
The outcome of posterior decompression surgery for multisegmental CSM is not correlated with the magnitude of postoperative backward shifting of the spinal cord. Extensive and consecutive decompression performed in conventional cervical laminoplasties is therefore not always necessary for multisegmental CSM.
Hatta
Yoichiro
Y
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. hilokai@zeus.eonet.ne.jp
Shiraishi
Tateru
T
Hase
Hitoshi
H
Yato
Yoshiyuki
Y
Ueda
Seiji
S
Mikami
Yasuo
Y
Harada
Tomohisa
T
Ikeda
Takumi
T
Kubo
Toshikazu
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002574:Cervical Vertebrae / Q000601:surgery; D019299:Decompression, Surgical / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013116:Spinal Cord / Q000473:pathology*; D013119:Spinal Cord Injuries / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D013130:Spinal Stenosis / Q000209:etiology / Q000473:pathology*; D016896:Treatment Outcome