Diagnosis and surgical challenges of extremely severe head and lumbar disc herniation in young patients: A case report

Table 1 A new grading system for migrated lumbar disc herniation

Grade	Direction and degree	Range of migration distance
1	Superior very high	Beyond the inferior margin of the upper pedicle
2	Superior high	From the inferior margin of the upper pedicle to the midpoint between the inferior margin of the upper pedicle and superior disc margin
3	Superior low	From the midpoint between the inferior margin of the upper pedicle and superior disc margin to the superior disc margin
4	Inferior low	From the inferior disc margin to the midpoint between the inferior margin of the lower pedicle and inferior disc margin
5	Inferior high	From the midpoint between the inferior margin of the lower pedicle and inferior disc margin to the inferior margin of the lower pedicle
6	Inferior very high	Beyond the inferior margin of the lower pedicle