Updated: 6/25/2021

Rheumatoid Cervical Spondylitis

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  • Summary
    • Rheumatoid Cervical Spondylitis comprises of 3 specific patterns of cervical spine instability seen in rheumatoid arthritis that consist of atlantoaxial subluxation, basilar invagination, and subaxial subluxation.
    • Diagnosis is made radiographically with cervical spine flexion-extension radiographs and supplemented with MRI studies to measure the degree of spinal cord compression. 
    • Treatment may be observation versus decompression with instrumentation depending on patient  neurological status, degree of mechanical instability, and severity of spinal cord compression. 
    • Present in 90% of patients with RA
      • diagnosis often missed
    • Cervical rheumatoid spondylitis includes three main patterns of instability
      • atlantoaxial subluxation
        • most common form of instability
      • basilar invagination
      • subaxial subluxation
  • Classification
      • Ranawat Classification
      • Class I 
      • Pain, no neurologic deficit
      • Class II
      • Subjective weakness, hyperreflexia, dysesthesias
      • Class IIIA
      • Objective weakness, long tract UMN signs, ambulatory
      • Class IIIB
      • Objective weakness, long tractUMNsigns, non-ambulatory. Do NOT operate
  • Presentation
    • Symptoms
      • symptoms and physical exam findings similar to cervical myelopathy
      • neck pain
      • neck stiffness
      • occipital headaches
        • due to lesser occipital nerve, which is branch of the C2 nerve root
      • gradual onset of weakness and loss of sensation
    • Physical exam
      • hyperreflexia
      • upper and lower extremity weakness
      • ataxia (gait instability and loss of hand dexterity)
  • Imaging
    • Radiographs
      • flexion-extension xrays
        • always obtain before elective surgery
        • see subtopic for radiographic lines and measurements
    • CT scan
      • useful to better delineate bony anatomy and for surgical planning
    • MRI
      • study of choice to evaluate degree of spinal cord compression and identify myelomalacia
  • General Treatment
    • Nonoperative
      • pharmacologic therapy
        • pharmacologic treatment for RA has seen significant recent advances
          • has led to a decrease in surgical intervention
    • Operative
      • spinal decompression and stabilization
        • indications
          • goal is to prevent further neurologic progression and surgery may not reverse existing deficits
  • Atlantoaxial Subluxation
    • Introduction
      • present in 50-80% of patients with RA
      • most common to have anterior subluxation of C1 on C2 (can have lateral and posterior)
    • Mechanism
      • caused by pannus formation between dens and ring of C1 that leads to the destruction of transverse ligament and dens
    • Radiographs
      • controlled flexion-extension views to determine AADI and SAC/PADI
        • AADI (anterior atlanto-dens interval)
          • instability defined as > 3.5 mm of motion between flexion and extension views
            • instability alone is not an indication for surgery
          • > 7 mm of motion may indicate disruption of alar ligament
          • > 10 mm motion is indication for surgery
            • because of increased risk of neurologic injury
        • PADI / SAC (posterior atlanto-dens interval and space available for cord describe same thing)
          • <14 mm is an indication for surgery
            • because of increased risk of neurologic injury
          • >13mm is the most important radiographic finding that may predict complete neural recovery after decompressive surgery
    • Treatment
      • nonoperative
        • indicated in stable atlantoaxial subluxation
      • operative
        • posterior C1-C2 fusion
          • general indications for surgery
            • AADI > 10 mm (even if no neuro deficits)
            • SAC / PADI < 14 mm (even if no neuro deficits)
            • progressive myelopathy
          • indications for posterior C1-2 fusion
            • able to reduce C1 to C2 so no need to remove posterior arch of C1
          • technique
            • adding transarticular screws eliminated need for halo immobilization (obtain preoperative CT to identify location of vertebral arteries)
        • occiput-C2 fusion ± resection of posterior C1 arch
          • indications
            • when atlantoaxial subluxation is combined with basilar invagination
            • resection of C1 posterior arch for complete decompression
              • leads to indirect decompression of anterior cord compression by pannus
              • may be required if atlantoaxial subluxation is not reducible
        • odontoidectomy
          • indications
            • rarely indicated
            • used as a secondary procedure when there is residual anterior cord compression due to pannus formation that fails to resolve with time following a posterior spinal fusion
              • pannus often resolves following posterior fusion alone due to decrease in instability
  • Basilar Invagination 
    • Introduction
      • also known as superior migration of odontoid (SMO)
        • tip of dens migrates above foramen magnum
      • present in 40% of RA patients
      • often seen in combination with fixed atlantoaxial subluxation
    • Mechanism
      • cranial migration of dens from erosion and bone loss between occiput and C1&C2
    • Imaging
      • radiographic lines
        • Ranawat C1-C2 index
          • center of C2 pedicle to a line connecting the anterior and posterior C1 arches
          • normal measurement in men is 17 mm, whereas in women it is 15 mm
          • distance of < 13 mm is consistent with impaction
          • most reproducible measurement
        • McGregor's line
          • line drawn from the posterior edge of the hard palate to the caudal posterior occiput curve
          • cranial settling is present when the tip of dens is more than 4.5 mm above this line
          • can be difficult when there is dens erosion
        • Chamberlain's line
          • line from dorsal margin of hard palate->posterior edge of the foramen magnum
          • abnormal if tip of dens > 5 mm proximal Chamberlain's line
          • normal distance from tip of dens to basion of occiput is 4-5 mm
          • this line is often hard to visualize on standard radiographs
        • McRae's line
          • defines the opening of the foramen magnum
          • the tip of the dens may protrude slightly above this line, but if the dens is below this line then impaction is not present
      • MRI
        • cervicomedullary angle < 135° suggest impending neurologic impairment
    • Treatment
      • operative
        • C2 to occiput fusion
          • indications
            • progressive cranial migration (> 5 mm)
            • neurologic compromise
            • cervicomedullary angle <135° on MRI
        • transoral or anterior retropharyngeal odontoid resection
          • indications
            • brain stem compromise
  • Subaxial Subluxation
    • Introduction
      • present in 20% with RA
      • often occurs at multiple levels
      • often combined with upper c-spine instability
      • lower spine involvement more common with
        • steroid use
        • males
        • seropositive RA
        • nodules present
        • severe RA
    • Pathophysiology
      • pannus formation and soft tissue instability of facet joints and Luschka joints
    • Radiographs
      • subaxial subluxation (of vertebral body) of >4mm or >20% indicates cord compression
      • cervical height index (body height/width) < 2.0 is almost 100% sensitive and specific for predicting neurologic compromise
    • Treatment
      • operative
        • posterior fusion and wiring
          • indications
            • > 4mm / >20% subaxial subluxation + intractable pain and neurologic symptoms
  • Operative Complications
    • Failure to improve symptoms
      • outcome less reliable in Ranawat Grade IIIB (objectively weak with UMN signs and nonambulatory)
    • Pseudoarthrosis
      • 10-20% pseudoarthrosis rate
      • decreased by extension to occiput
    • Adjacent level degeneration

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(SBQ18SP.9) A 72-year-old female presents with neck pain and an occipital headache. A CT scan and MRI are shown in Figures A and B respectively. What laboratory finding would most likely be found in this patient?

QID: 211201

Positive anti-cyclic citrullinated protein



Elevated CRP and WBC






M spike present on serum protein electrophoresis



Mutation in EXT gene



L 3 A

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(SBQ18SP.10) A 73-year-old female with a history of rheumatoid arthritis presents to clinic with worsening bilateral upper extremity paresthesias, clumsiness, and weakness. On exam, she has a positive Babinski, intact sensation to light touch, and 4/5 motor in the bilateral upper extremities. Her cervical MRI is shown in Figure A. What is the most appropriate next step in treatment for the upper cervical spine?

QID: 211212

Observation and soft collar



Spinal dose steroids



Posterior fusion with or without decompression



Transoral pannus resection alone



Transoral pannus resection followed by posterior occipitocervical fusion



L 3 A

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(OBQ06.146) A 60-year-old woman with rheumatoid arthritis has long term neck pain and new onset of difficulty holding cards in her weekly poker tournament. She does not complain of weakness, but states she has become "clumsy" in her old age, fumbling with buttons and dropping her change. On exam she has hyperreflexia, but no weakness. Radiographs show atlantoaxial subluxation. She is considering decompressive surgery, but wants to know if she will recover function. Which radiographic marker may predict neural recovery after decompression?

QID: 332

Posterior atlanto-dens interval of >13mm



Atlanto-dens interval of <5mm



Subaxial subluxation of <3.5mm



Basilar invagination <0.5cm



Rotary subluxation of <10 degrees



L 2 C

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(OBQ05.48) A 63-year-old woman with rheumatoid arthritis has long standing neck pain and new onset of difficulty with manual dexterity, such as buttoning her shirt and holding small objects. She reports difficulty walking up the stairs, and reports she feels increasingly unsteady on her feet. On exam she has 4+ patellar reflexes. Flexion and extension radiographs are shown in Figure A and B. What is the most appropriate treatment at this time?

QID: 84

Immobilization in a soft cervical collar for 6 weeks



Halo immobilization for six weeks



Transoral odontoid resection



Occipitocervical fusion with instrumentation



Posterior C1-C2 fusion with instrumentation



L 2 C

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