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Classification for Rheumatoid Arthritis Affecting Cervical Spine

Purpose: To classify involvement of the upper cervical spine in a patient with rheumatoid arthritis using the classification of Pellicci et al.

Description

Rheumatoid arthritis may result in instability of the upper cervical spine. Pellicci et al developed a classification system to describe this involvement. The authors are from the Hospital for Special Surgery in New York City.


 

Parameters:

(1) pain

(2) neural involvement

(3) radiographic measurement in a lateral view of the cervical spine

(3a) atlanto-axial subluxation (AAS) in mm

(3b) subaxial subluxation (SAS) in percent (aka C2-C3 translation)

(3c) superior migration (SM) of the odontoid process (OP)

Parameter

Finding

Grade

pain

none

0

 

intermittent, relieved by NSAIDS

I

 

intermittent, requires narcotics and a collar

II

 

severe, constant pain, resulting in disability

III

neural involvement

none

0

 

hyperreflexia, dysesthesias

I

 

posterior column deficit, mild to moderate pain

II

 

severe weakness, significant functional disability

III

atlanto-axial subluxation

<= 2.5 mm

0

 

2.6 to 4.9 mm

I

 

5.0 to 7.9 mm

II

 

>= 8 mm

III

subaxial subluxation

<= 15%

0

 

15.1 to 24.9%

I

 

25 to 32.9%

II

 

>= 33%

III

superior migration OP

>= 13 mm

0

 

6 to 12 mm

I

 

0 to 5 mm

II

 

< 0 (C2 pedicles above C1 line)

III

 

where:

• AAS is the distance between the posterior cortex of the anterior arch of C1 and the anterior cortex of the odontoid process on C2 in mm.

• SAS is measured by the anterior displacement of the posteroinferior angle of a cervical vertebral body relative to the posterosuperior angle of the cervical vertebral body immediately below.

• SM is measured as the perpendicular distance from the center of the C2 pedicles to a line connecting the anterior arch to spinous process of C1. The normal distance is >= 13 mm.

 

The final grade can be determined in several ways. In the implementation the maximum grade for the 5 measures will be assigned as the final grade.

 


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Specialty

Objective

ICD-10