Table 1 Radiological adjacent segment pathology (RASP) grading on plain radiographs.

From: The impact of over-distraction on adjacent segment pathology and cage subsidence in anterior cervical discectomy and fusion

Grade*

Plain radiograph findings

0

Normal

I

Hypertrophy of the uncinate process

IIA

Ossification to < 50% of disc height

IIB

Ossification to < 50% of disc height + disc space narrowing

IIIA

Ossification to ≥ 50% of disc height

IIIB

Ossification to ≥ 50% of disc height + disc space narrowing

IV

Complete bridging of the adjacent disc space

V

Disc space narrowing to > 50% of normal disc height + posterior osteophyte or displacement

  1. *The grading system was proposed by Hilibrand et al.7 and modified by Chung et al.17.
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