Surgical Reduction and Direct Repair Using Pedicle Screw-Rod-Hook Fixation in Adult Patients with Low-Grade Isthmic Spondylolisthesis

Table 4

Lumbar disc degeneration observed on MRIs by the Pfirrmann grading system.

Pregrades	FFU of SSD (n)					FFU of USD (n)
	1	2	3	4	5	1	2	3	4	5
1	2	3				7	1
2		16	2				35	13
3			20	21			1	5	2

N, number of patients; FFU, final follow-up; SSD, surgical segmental disc; USD, upper segmental disc.