TABLE V

OPLL Predictors of Surgical Outcomes: Results of Prognostic Studies without Multivariate Analysis*

StudyPatient Population, Surgical TreatmentOutcome Associated withOutcome Not Associated with
Postoperative JOA
 Chen et al.42 (2009)OPLL (n = 138), anterior cervical corpectomy with fusionDural ossification
 Fujiyoshi et al.8 (2008)OPLL (n = 27), laminectomy with fusion or laminoplastyK-line (+/−)
 Iwasaki et al.44 (2007)OPLL (n = 93), laminoplasty or anterior discectomy with fusionLaminoplasty
  • • Shape of ossification (plateau-shaped or hill-shaped)

Anterior discectomy with arthrodesis
  • • Shape of ossification (plateau-shaped or hill-shaped)

 Matsuoka et al.27 (2001)OPLL (n = 63), anterior floating methodType of OPLL, occupying ratio, thickness of ossification, space available for spinal cord
 Matsuyama et al.9 (2004)OPLL (n = 44), laminoplastyConfiguration of spinal cord (teardrop, boomerang and triangular)
 Ogawa et al.28 (2004)OPLL (n = 72), anterior surgery or laminoplastyOccupying ratio, type of OPLL
 Nagashima et al.29 (2013)OPLL (n = 68), laminoplastyK-line (+/−)
JOA recovery rate
 Baba et al.30 (1994)OPLL (n = 85), anterior cervical decompression with fusionOccupying ratio
 Baba et al.31 (1995)OPLL (n = 47), laminoplastyOccupying ratio
 Baba et al.32 (1995)OPLL (n = 57), laminoplastyOccupying ratio
 Chen et al.42 (2009)OPLL (n = 138), anterior cervical corpectomy with fusionDural ossification
 Choi et al.33 (2014)OPLL (n = 74), laminectomy with fusion or laminoplastyOccupying ratio, space available for spinal cordType of OPLL
 Fujiyoshi et al.8 (2008)OPLL (n = 27), laminectomy with fusion or laminoplastyK-line (+/−)
 Iwasaki et al.44 (2007)OPLL (n = 93), laminoplasty or anterior decompression with fusionLaminoplasty
  • • Shape of ossification (plateau-shaped or hill-shaped)

Anterior decompression with fusion
  • • Shape of ossification (plateau-shaped or hill-shaped)

 Liu et al.34 (2013)OPLL (n = 127), anterior surgery or laminoplastySeverity of canal stenosis
 Matsuoka et al.27 (2001)OPLL (n = 63), anterior floating methodType of OPLL, occupying ratio, thickness of ossification, space available for spinal cord
 Matsuyama et al.9 (2004)OPLL (n = 44), laminoplastyConfiguration of spinal cord (teardrop, boomerang, or triangular)
 Morio et al.35 (1999)OPLL (n = 36), laminoplasty or anterior decompression with fusionOccupying ratio
 Nagashima et al.29 (2013)OPLL (n = 68), laminoplastyK-line (+/−)
 Yang et al.11 (2015)OPLL (n = 268), anterior cervical corpectomy with fusionType of dural ossification
mJOA recovery rate
 Hossam et al.36 (2013)OPLL (n = 30), anterior cervical corpectomy with fusionType of OPLL
JOA recovery rate (≥50%, <50%)
 Chen et al.43 (2009)OPLL (n = 83), laminectomy with fusionOccupying ratio (%), type of OPLL (local, segmental, continuous, mixed), extent of OPLL
 Fujimori et al.41 (2014)OPLL (n = 27), anterior decompression with fusion or laminoplastyAnterior decompression with fusion
  • • Occupying ratio

Laminoplasty
  • • OPLL shape (hill versus plateau), occupying ratio, space available for spinal cord, K-line (+/−)

Anterior decompression with fusion
  • • OPLL shape (hill-shaped, plateau-shaped), space available for spinal cord, K-line (+/−)

 Maruo et al.37 (2014)OPLL (n = 45), laminoplastyOccupying ratio
JOA recovery rate (≥40%, <40%)
 Masaki et al.38 (2007)OPLL (n = 40), laminoplastyOccupying ratio
JOA recovery rate (≥75%, 75% to ≥50%, 50% to ≥25%, <25%)
 Chen et al.42 (2009)OPLL (n = 138), anterior cervical corpectomy with fusionDural ossification
 Yang et al.11 (2015)OPLL (n = 268), anterior cervical corpectomy with fusionType of dural ossification
JOA recovery rate (>75%, 75% to >50%, 50% to >0%, ≤0%)
 Goto and Kita39 (1995)OPLL (n = 115), anterior or posterior decompressionOPLL thickness, space available for spinal cord
Nurick score (≥1 grade improvement versus no change or deterioration)
 Kommu et al.40 (2014)OPLL (n = 63), anterior and/or posterior decompressionNumber of OPLL levels
Nurick improvement
 Hossam et al.36 (2013)OPLL (n = 30), anterior cervical corpectomy with fusionType of OPLL
  • * mJOA = modified Japanese Orthopaedic Association.