Effect of Percutaneous Kyphoplasty on the progression of intervertebral disc degeneration: a retrospective cohort study

Table 1 Modified grading system for lumbar disc degeneration*

Grade	Signal from the nucleus and inner fibres of the annulus	Distinction between inner and outer fibres of the annulus at the posterior aspect of the disc	Height of disc
1	Uniformly hyperintense, equal to CSF*	Distinct	Normal
2	Hyperintense (> presacral fat and < CSF*) ± hypointense intranuclear cleft	Distinct	Normal
3	Hyperintense though < presacral fat	Distinct	Normal
4	Mildly hyperintense (slightly > outer fibresof the annulus)	Indistinct	Normal
5	Hypointense (= outer fibres of the annulus)	Indistinct	Normal
6	Hypointense	Indistinct	< 30% reduction in disc height
7	Hypointense	Indistinct	30–60% reduction in disc height
8	Hypointense	Indistinct	> 60% reduction in disc height

This table is reproduced from Griffith et al. [21]. Different levels are determined by signals from the nucleus and inner fibres of the annulus, distinction between inner and outer fibres of the annulus at the posterior aspect of the disc, and disc height
^*CSF Cerebrospinal fluid

ISSN: 1749-799X