Korean J Neurotrauma.  2018 Oct;14(2):118-122. 10.13004/kjnt.2018.14.2.118.

Risk Factors for Hinge Fracture Associated with Surgery Following Cervical Open-Door Laminoplasty

• Lee JH
• Chough CK

• KMID: 2424323
• DOI: http://doi.org/10.13004/kjnt.2018.14.2.118

Abstract

OBJECTIVE
The purpose of this study was to analyze the risk factors for hinge fracture (HF) and non-union during cervical open-door laminoplasty (CODL).
METHODS
We included 25 patients who underwent CODL with available serial computed tomography scans acquired at 2 days and 1 year postoperatively. Patients' medical records and radiographic data were reviewed. Risk factors related to the surgical procedures were evaluated including the lamina angle, spinous angle, difference in the lamina angle, outer cortex location (OCL), and inner cortex location.
RESULTS
There were a total of 76 hinges. Of these, 44 laminae were classified as deformed hinges, and 32 were classified as fragmented hinges. Additionally, 66 laminae were healed completely, and 10 laminae were not healed by 12 months postoperatively. The OCL (odds ratio, 70.45; 95% confidence interval, 7.73-641.76) was identified as a predictor of HFs immediately following CODL. However, none of the factors we evaluated was related to hinge non-union.
CONCLUSION
A medially located hinge gutter ( >1.9 mm from the pedicle on the outer cortex) seems to be an important risk factor for HFs following CODL. However, the hinge healing status was not related to the surgical technique.

Keyword

Cervical vertebrae; Fractures, bone; Laminoplasty; Risk factors

MeSH Terms

Cervical Vertebrae
Female
Fractures, Bone
Humans
Laminoplasty*
Medical Records
Risk Factors*

Figure

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  FIGURE 1 (A) Schematic diagram of the lamina angle (LA) and spinous angle (SA). SA (a) was defined as the angle between the parallel line to spinous process and the perpendicular line to virtual line crossing both lateral mass posteriorly. LA (b) was defined as the angle between parallel line to the hinge side lamina and virtual line crossing both lateral mass posteriorly. (B) Radiographic measurements of hinge gutter location. Inner cortex layer (c) was defined as distance from pedicle to inner cortical bone of hinge, and outer cortex layer (d) was defined as distance from pedicle to outer cortical bone of hinge.

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  FIGURE 2 Receiver-operating characteristics curves of risk factors. (A) Outer cortex location, (B) inner cortex location, (C) lamina angle, (D) spinous angle, and (E) difference of lamina angle. AUC: area under curve.

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