Prediction of spinal canal expansion following double-door cervical laminoplasty / 中华骨科杂志

ABSTRACT

Objective To ratiocinate the formula of relationship between opening size of laminoplasty and the increment of sagittal canal diameter following double-door cervical laminoplasty and to predict the increment of sagittal canal diameter and the cross sectional area of canal according to the opening size of laminoplasty.Methods Twenty patients (12 males and 8 females) with multilevel cervical spondylotic myelopathy had undergone double-door cervical laminoplasty (C3-C7 in 9 patients and C3-C6 in 11 patients,89 segments) in our institution between September 2010 and January 2013.The formula describing the relationship between the opening size of laminoplasty and the increment of sagittal diameter was deduced.The parameters of pre-and post-operative computed tomography scans of 20 patients who had undergone laminoplasty surgery were measured by picture archiving and communication system (PACS) software,and the increment of sagittal canal diameter and the cross sectional area of canal were predicted when the opening size of laminoplasty were 6 mm,8 mm,10 mm,12 mm,14 mm and 16 mm according to the formula.Results Increment of sagittal canal diameter and canal area respectively showed significant difference in the same segment laminoplasty.Increment of sagittal canal diameter between various groups in the same segment (C3-C6) showed significant difference.Increment of sagittal canal diameter between the opening size of 14 mm and 16 mm in C7 laminoplasty showed no significant difference.Increment of sagittal canal diameter was increased steadily following C3-C7 double-door laminoplasty with opening sizes of 6 mm,8 mm,10 mm,12 mm,14mm and 16mm,but the increasing trend in sagittal canal diameter diminished gradually.Conclusion Increment of sagittal canal diameter and canal area following C3-C7 laminoplasty can be accurately predicted according to the opening size of laminoplasty by this formula.The formula can help operator to perform double-door cervical laminoplasty based on accurate individual laminoplasty opening size,which prevents inadequate or excessive opening.