rheumatoid neck

epidemiology

· neck involved in 60%

· most common lesions are

· atlantoaxial subluxation

· basilar invagination

· subaxial subluxation

pathology

· process causes

· pannus formation

· capsular distension

· joint and ligament destruction

· results in

· pressure from pannus

· collapse from joint erosion

· instability from ligament attrition

· upper C spine more vulnerable to problems

· stability depends on ligaments

· no inherent bony stability

· surrounded by synovial joints

Atlantoaxial subluxation

· horizontal translocation of odontoid can occur due to

· erosion of otontoid

· attrition of transverse ligament

· can result in cord compression and myelopathy

Basilar invagination

· vertical translocation of odontoid can occur due to

· collapse of lateral masses of atlas and axis

· can result in compression of upper cord and brainstem

Subaxial subluxation

· forward subluxation of one vertebra on subjacent one due to

· destructive changes of facet joints

· destruction of disc

· end-plate collapse

· can result in canal stenosis

Precipitants

· neurological compromise may be worsened by vertebral artery involvement

clinical features

Symptoms

Pain

· deep ache in neck

· worse in morning

· precipitated by movement

· radiates down shoulders

Stiffness

· decreased ROM

· movement associated with crepitation

Neurological

· parasthesiae

· most common and earliest symptom

· usually in distal parts of limbs

· may be worsened by sneezing or neck flexion (Lhermitte)

· weakness

· may have sudden tetraparesis

· may be gradual and attributed to RA

· autonomic disturbance

· frequency or retention

· constipation

Signs

· of neurological deficit

· often difficult because of joint involvement

· typically patchy

· may be cranial nerve and brainstem involvement

· trigeminal (facial numbness, depressed corneal reflex)

· ponse (swallowing)

radiology

General

· osteoporosis

· disc space narrowing without osteophytes

· erosion of end-plates

· erosion and ankylosis of facet joints

· erosion of odontoid

Atlantoaxial subluxation

· seen on lateral flexion-extension views

· subluxation defined as > 3 mm ADI

· instability defined as 3 mm difference in ADI from flexion to extension

· severe instability defined as 7 mm difference in ADI

· cord compression if space available for cord (behind peg) < 13 mm

Basilar invagination

· seen on lateral view

· McGregor’s line used

· hard palate to lowest part of occipital curve

· invagination present if tip of dens above line by 4.5 mm

· severe invagination present if more than

· 8 mm in men

· 10 mm in women

Subaxial subluxation

· seen on lateral view

· present if loss of alignment of posterior margin of adjacent vertebral bodies > 2 mm

treatment

Preventative

· C spine x-rays in all patients that may involve neck manipulation

· general anaesthetic

· endoscopy

· dental treatment

· if instability present, precautions against sudden neck movement

Operative

Indications

· progressive instability

· neurological deficit

Technique

· posterior cervical fusion

· occipitoaxial

· atlantoaxial

· subaxial

Complications

· death

· pseudarthrosis

· fixation failure

· poor wound healing