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Modified K-line in magnetic resonance imaging predicts insufficient decompression of cervical laminoplasty.
Spine (Phila Pa 1976). 2013 Mar 15; 38(6):496-501.S

Abstract

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

To clarify preoperative factors predicting unsatisfactory indirect decompression after laminoplasty in patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

Many authors have shown that inadequate indirect decompression after laminoplasty can inhibit neural recovery and should be considered a complication. We previously demonstrated that residual anterior compression of the spinal cord (ACS) impaired recovery of upper extremity motor function. Although the K-line has been established as a predictive index indicating that laminoplasty is required in patients with ossification of the posterior longitudinal ligament, it remains unclear what preoperative factors can predict insufficient posterior cord decompression in patients with cervical spondylotic myelopathy.

METHODS

Forty-six consecutive patients who underwent laminoplasty for the treatment of cervical spondylotic myelopathy at our hospital were reviewed. A modified K-line was defined as the line connecting the midpoints of the spinal cord at C2 and C7 on a T1-weighted sagittal magnetic resonance image. We also determined the minimum interval between the tip of local kyphosis and a line connecting the midpoint of the cord at the level of the inferior endplates of C2 and C7 (INTmin) on the midsagittal image. Data analysis involved logistic regression and receiver operating characteristic curve analysis to select the most valuable index for predicting postoperative ACS.

RESULTS

Ten patients had ACS immediately after laminoplasty. Logistic regression analysis showed that INTmin was a significant predictive factor for the occurrence of postoperative ACS (odds ratio = 0.485; 95% confidence interval = 0.29-0.81; P = 0.02). Receiver operating characteristic curve analysis showed an area under the curve of 0.871. A cutoff of 4.0 mm had a sensitivity of 80% and a specificity of 80.6% for prediction of postoperative ACS.

CONCLUSION

The parameter INTmin correlated with the occurrence of postoperative ACS. A cutoff point of 4.0 mm is most appropriate for alerting spine surgeons to a high likelihood of postoperative ACS.

Authors+Show Affiliations

Department of Orthopedic Surgery, Tokyo Medical and Dental University, Tokyo 113-8519, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22986838

Citation

Taniyama, Takashi, et al. "Modified K-line in Magnetic Resonance Imaging Predicts Insufficient Decompression of Cervical Laminoplasty." Spine, vol. 38, no. 6, 2013, pp. 496-501.
Taniyama T, Hirai T, Yamada T, et al. Modified K-line in magnetic resonance imaging predicts insufficient decompression of cervical laminoplasty. Spine. 2013;38(6):496-501.
Taniyama, T., Hirai, T., Yamada, T., Yuasa, M., Enomoto, M., Yoshii, T., Kato, T., Kawabata, S., Inose, H., & Okawa, A. (2013). Modified K-line in magnetic resonance imaging predicts insufficient decompression of cervical laminoplasty. Spine, 38(6), 496-501. https://doi.org/10.1097/BRS.0b013e318273a4f7
Taniyama T, et al. Modified K-line in Magnetic Resonance Imaging Predicts Insufficient Decompression of Cervical Laminoplasty. Spine. 2013 Mar 15;38(6):496-501. PubMed PMID: 22986838.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Modified K-line in magnetic resonance imaging predicts insufficient decompression of cervical laminoplasty. AU - Taniyama,Takashi, AU - Hirai,Takashi, AU - Yamada,Tsuyoshi, AU - Yuasa,Masato, AU - Enomoto,Mitsuhiro, AU - Yoshii,Toshitaka, AU - Kato,Tsuyoshi, AU - Kawabata,Shigenori, AU - Inose,Hiroyuki, AU - Okawa,Atsushi, PY - 2012/9/19/entrez PY - 2012/9/19/pubmed PY - 2013/9/7/medline SP - 496 EP - 501 JF - Spine JO - Spine VL - 38 IS - 6 N2 - STUDY DESIGN: A retrospective single-center study. OBJECTIVE: To clarify preoperative factors predicting unsatisfactory indirect decompression after laminoplasty in patients with cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA: Many authors have shown that inadequate indirect decompression after laminoplasty can inhibit neural recovery and should be considered a complication. We previously demonstrated that residual anterior compression of the spinal cord (ACS) impaired recovery of upper extremity motor function. Although the K-line has been established as a predictive index indicating that laminoplasty is required in patients with ossification of the posterior longitudinal ligament, it remains unclear what preoperative factors can predict insufficient posterior cord decompression in patients with cervical spondylotic myelopathy. METHODS: Forty-six consecutive patients who underwent laminoplasty for the treatment of cervical spondylotic myelopathy at our hospital were reviewed. A modified K-line was defined as the line connecting the midpoints of the spinal cord at C2 and C7 on a T1-weighted sagittal magnetic resonance image. We also determined the minimum interval between the tip of local kyphosis and a line connecting the midpoint of the cord at the level of the inferior endplates of C2 and C7 (INTmin) on the midsagittal image. Data analysis involved logistic regression and receiver operating characteristic curve analysis to select the most valuable index for predicting postoperative ACS. RESULTS: Ten patients had ACS immediately after laminoplasty. Logistic regression analysis showed that INTmin was a significant predictive factor for the occurrence of postoperative ACS (odds ratio = 0.485; 95% confidence interval = 0.29-0.81; P = 0.02). Receiver operating characteristic curve analysis showed an area under the curve of 0.871. A cutoff of 4.0 mm had a sensitivity of 80% and a specificity of 80.6% for prediction of postoperative ACS. CONCLUSION: The parameter INTmin correlated with the occurrence of postoperative ACS. A cutoff point of 4.0 mm is most appropriate for alerting spine surgeons to a high likelihood of postoperative ACS. SN - 1528-1159 UR - https://www.unboundmedicine.com/medline/citation/22986838/Modified_K_line_in_magnetic_resonance_imaging_predicts_insufficient_decompression_of_cervical_laminoplasty_ L2 - http://dx.doi.org/10.1097/BRS.0b013e318273a4f7 DB - PRIME DP - Unbound Medicine ER -