Postoperative K-line conversion from negative to positive is independently associated with a better surgical outcome after posterior decompression with instrumented fusion for K-line negative cervical ossification of the posterior ligament
- 34 Downloads
Addition of posterior instrumented fusion to laminoplasty (posterior decompression with instrumented fusion: PDF) can improve the surgical outcome of patients with K-line (−) cervical ossification of the longitudinal ligament (OPLL) compared with laminoplasty alone. We sought to elucidate the factors that are significantly associated with a better outcome after PDF for K-line (−) OPLL.
The present study included 38 patients who underwent PDF for K-line (−) OPLL and were followed up for at least 1 year after surgery. Clinical outcome was assessed using Japanese Orthopedic Association (JOA) scores for cervical myelopathy and the recovery rate was calculated. Patients who belonged to the upper quartile of all the patients according to rank order of the JOA score recovery rate were considered to have a good outcome. The correlations between good outcome, patient factors and imaging assessments were analyzed statistically.
Univariate analyses showed that postoperative conversion of K-line from (−) to (+) (p = 0.004), no increase in the sagittal vertical axis from the center of gravity of the head to C7 (p = 0.07), and a lower grade of preoperative intramedullary T2-signal intensity (p = 0.03) were candidates for the association. Stepwise logistic regression analysis revealed that postoperative K-line conversion from (−) to (+) is an independent factor that is significantly associated with a better surgical outcome (p = 0.04).
Postoperative K-line conversion from (−) to (+) is a factor independently associated with a better surgical outcome.
KeywordsOPLL Cervical spine Fusion surgery
Compliance with ethical standards
Conflict of interest
All the co-authors have no conflict of interest in the present study.
- 5.Sakai K, Okawa A, Takahashi M et al (2012) Five-year follow-up evaluation of surgical treatment for cervical myelopathy caused by ossification of the posterior longitudinal ligament: a prospective comparative study of anterior decompression and fusion with floating method versus laminoplasty. Spine 37:367–376CrossRefPubMedGoogle Scholar
- 10.Fujiyoshi T, Yamazaki M, Okawa A et al (2011) Outcome of posterior decompression surgery for cervical OPLL patients of the K-line (−) group: laminoplasty versus posterior decompression with instrumented fusion. J Spine Res 2:231–235Google Scholar
- 11.Koda M, Mochizuki M, Konishi H et al (2016) Comparison of clinical outcomes between laminoplasty, posterior decompression with instrumented fusion, and anterior decompression with fusion for K-line (−) cervical ossification of the posterior longitudinal ligament. Eur Spine J 25:2294–2301CrossRefPubMedGoogle Scholar
- 12.Japanese Orthopaedic Association (1994) Scoring system for cervical myelopathy. Nippon Seikeigeka Gakkai Zasshi 68:490–503 (in Japanese) Google Scholar
- 13.Hirabayashi K, Toyama Y (1997) Choice of surgical procedure for cervical ossification of the posterior longitudinal ligaments. In: Yonenobu K, Sakou T, Ono K (eds) ossification of the posterior longitudinal ligament. Springer-Verlag, Tokyo, pp 135–142Google Scholar
- 14.Tsuyama N (1984) Ossification of the posterior longitudinal ligament of the spine. Clin Orthop Relat Res 184:71–84Google Scholar
- 17.Yoshii T, Sakai K, Hirai T et al (2016) Anterior decompression with fusion versus posterior decompression with fusion for massive cervical ossification of the posterior longitudinal ligament with a ≥ 50% canal occupying ratio: a multicenter retrospective study. Spine J 16:1351–1357CrossRefPubMedGoogle Scholar