K-line (−) in the neck-flexed position affects surgical outcomes in patients with ossification of the posterior longitudinal ligament after muscle-preserving selective laminectomy

Satoshi Nori, Ryoma Aoyama, Ken Ninomiya, Satoshi Suzuki, Ukei Anazawa, Tateru Shiraishi

Research output: Contribution to journalArticle

Abstract

Background: Posterior cervical decompression results in favorable outcomes for K-line (+) ossification of the posterior longitudinal ligament (OPLL) patients. However, even for patients with K-line (+) in the neck neutral position, K-line (−) in the neck-flexed position (flexion K-line (−)) may affect surgical outcomes. We investigated the influence of flexion K-line (−) on surgical outcomes after muscle-preserving selective laminectomy using multivariate analysis. Methods: This study involved 113 OPLL patients with K-line (+) in the neck neutral position who underwent muscle-preserving selective laminectomy. Patients were divided into flexion K-line (+) (n = 90) and flexion K-line (−) (n = 23) groups. We analyzed the influence of a flexion K-line (−) on radiological and surgical outcomes. We conducted a multivariate analysis to analyze the factors affecting surgical outcomes. Results: The patients with a flexion K-line (−) had a larger C2–C7 sagittal vertical axis (preoperatively, P = 0.042; postoperatively, P = 0.021), narrower postoperative clearance of the spinal cord (P = 0.003), a smaller proportion of segmental-type OPLL (P < 0.001), and a greater OPLL occupancy ratio (P < 0.001). The recovery rate measured by the Japanese Orthopedic Association (JOA) score was poorer in patients with a flexion K-line (−) (17.6 ± 32.2%) than in those with a flexion K-line (+) (35.3 ± 29.5%) (P = 0.013). Multiple linear regression analysis revealed that the flexion K-line (−) affected the recovery rate of the JOA score (β = −0.233, P = 0.013). Conclusions: Even for patients with K-line (+) OPLL, the flexion K-line (−) affects surgical outcomes. The flexion K-line (−) is a useful predictor of poor surgical outcomes after posterior decompression surgery.

Original languageEnglish
JournalJournal of Orthopaedic Science
DOIs
Publication statusAccepted/In press - 2019 Jan 1

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Ossification of Posterior Longitudinal Ligament
Laminectomy
Neck
Muscles
Decompression
Orthopedics
Multivariate Analysis
Statistical Factor Analysis
Linear Models
Spinal Cord
Regression Analysis

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

Cite this

@article{45641e962e5d4d8d8bc571399ddee4f1,
title = "K-line (−) in the neck-flexed position affects surgical outcomes in patients with ossification of the posterior longitudinal ligament after muscle-preserving selective laminectomy",
abstract = "Background: Posterior cervical decompression results in favorable outcomes for K-line (+) ossification of the posterior longitudinal ligament (OPLL) patients. However, even for patients with K-line (+) in the neck neutral position, K-line (−) in the neck-flexed position (flexion K-line (−)) may affect surgical outcomes. We investigated the influence of flexion K-line (−) on surgical outcomes after muscle-preserving selective laminectomy using multivariate analysis. Methods: This study involved 113 OPLL patients with K-line (+) in the neck neutral position who underwent muscle-preserving selective laminectomy. Patients were divided into flexion K-line (+) (n = 90) and flexion K-line (−) (n = 23) groups. We analyzed the influence of a flexion K-line (−) on radiological and surgical outcomes. We conducted a multivariate analysis to analyze the factors affecting surgical outcomes. Results: The patients with a flexion K-line (−) had a larger C2–C7 sagittal vertical axis (preoperatively, P = 0.042; postoperatively, P = 0.021), narrower postoperative clearance of the spinal cord (P = 0.003), a smaller proportion of segmental-type OPLL (P < 0.001), and a greater OPLL occupancy ratio (P < 0.001). The recovery rate measured by the Japanese Orthopedic Association (JOA) score was poorer in patients with a flexion K-line (−) (17.6 ± 32.2{\%}) than in those with a flexion K-line (+) (35.3 ± 29.5{\%}) (P = 0.013). Multiple linear regression analysis revealed that the flexion K-line (−) affected the recovery rate of the JOA score (β = −0.233, P = 0.013). Conclusions: Even for patients with K-line (+) OPLL, the flexion K-line (−) affects surgical outcomes. The flexion K-line (−) is a useful predictor of poor surgical outcomes after posterior decompression surgery.",
author = "Satoshi Nori and Ryoma Aoyama and Ken Ninomiya and Satoshi Suzuki and Ukei Anazawa and Tateru Shiraishi",
year = "2019",
month = "1",
day = "1",
doi = "10.1016/j.jos.2019.10.002",
language = "English",
journal = "Journal of Orthopaedic Science",
issn = "0949-2658",
publisher = "Springer Japan",

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TY - JOUR

T1 - K-line (−) in the neck-flexed position affects surgical outcomes in patients with ossification of the posterior longitudinal ligament after muscle-preserving selective laminectomy

AU - Nori, Satoshi

AU - Aoyama, Ryoma

AU - Ninomiya, Ken

AU - Suzuki, Satoshi

AU - Anazawa, Ukei

AU - Shiraishi, Tateru

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Background: Posterior cervical decompression results in favorable outcomes for K-line (+) ossification of the posterior longitudinal ligament (OPLL) patients. However, even for patients with K-line (+) in the neck neutral position, K-line (−) in the neck-flexed position (flexion K-line (−)) may affect surgical outcomes. We investigated the influence of flexion K-line (−) on surgical outcomes after muscle-preserving selective laminectomy using multivariate analysis. Methods: This study involved 113 OPLL patients with K-line (+) in the neck neutral position who underwent muscle-preserving selective laminectomy. Patients were divided into flexion K-line (+) (n = 90) and flexion K-line (−) (n = 23) groups. We analyzed the influence of a flexion K-line (−) on radiological and surgical outcomes. We conducted a multivariate analysis to analyze the factors affecting surgical outcomes. Results: The patients with a flexion K-line (−) had a larger C2–C7 sagittal vertical axis (preoperatively, P = 0.042; postoperatively, P = 0.021), narrower postoperative clearance of the spinal cord (P = 0.003), a smaller proportion of segmental-type OPLL (P < 0.001), and a greater OPLL occupancy ratio (P < 0.001). The recovery rate measured by the Japanese Orthopedic Association (JOA) score was poorer in patients with a flexion K-line (−) (17.6 ± 32.2%) than in those with a flexion K-line (+) (35.3 ± 29.5%) (P = 0.013). Multiple linear regression analysis revealed that the flexion K-line (−) affected the recovery rate of the JOA score (β = −0.233, P = 0.013). Conclusions: Even for patients with K-line (+) OPLL, the flexion K-line (−) affects surgical outcomes. The flexion K-line (−) is a useful predictor of poor surgical outcomes after posterior decompression surgery.

AB - Background: Posterior cervical decompression results in favorable outcomes for K-line (+) ossification of the posterior longitudinal ligament (OPLL) patients. However, even for patients with K-line (+) in the neck neutral position, K-line (−) in the neck-flexed position (flexion K-line (−)) may affect surgical outcomes. We investigated the influence of flexion K-line (−) on surgical outcomes after muscle-preserving selective laminectomy using multivariate analysis. Methods: This study involved 113 OPLL patients with K-line (+) in the neck neutral position who underwent muscle-preserving selective laminectomy. Patients were divided into flexion K-line (+) (n = 90) and flexion K-line (−) (n = 23) groups. We analyzed the influence of a flexion K-line (−) on radiological and surgical outcomes. We conducted a multivariate analysis to analyze the factors affecting surgical outcomes. Results: The patients with a flexion K-line (−) had a larger C2–C7 sagittal vertical axis (preoperatively, P = 0.042; postoperatively, P = 0.021), narrower postoperative clearance of the spinal cord (P = 0.003), a smaller proportion of segmental-type OPLL (P < 0.001), and a greater OPLL occupancy ratio (P < 0.001). The recovery rate measured by the Japanese Orthopedic Association (JOA) score was poorer in patients with a flexion K-line (−) (17.6 ± 32.2%) than in those with a flexion K-line (+) (35.3 ± 29.5%) (P = 0.013). Multiple linear regression analysis revealed that the flexion K-line (−) affected the recovery rate of the JOA score (β = −0.233, P = 0.013). Conclusions: Even for patients with K-line (+) OPLL, the flexion K-line (−) affects surgical outcomes. The flexion K-line (−) is a useful predictor of poor surgical outcomes after posterior decompression surgery.

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