Cervical Spine Changes in Rheumatoid Arthritis

Abstract

Väitöskirjatyössä tutkittiin nivelreuman aiheuttamien kaularankamuutosten diagnostiikkaa, esiintyvyyttä, riskitekijöitä ja hoitoa sekä muutoksiin liittyvää kuolleisuutta. Työssä käytettiin epidemiologisia ja radiologisia menetelmiä.

Tutkimustyössä osoitettiin että jopa 42%lle nivelreumapotilaista kehittyy 20-vuoden seurannassa kaularangan alueen nikamien välisiä siirtymiä. Riski kaularankamuutoksiin oli suurentunut potilailla, joilla esiintyi myös muiden nivelten vaurioita tai alentunut reisiluun kaulan luuntiheys. Jopa 10%lla potilaista muutokset olivat niin vaikeita, että ne saattavat aiheuttaa hermojuurten tai selkäytimen vaurioita. Totesimme myös, että epidemiologisesti kaularankamuutokset eivät lyhennä nivelreumapotilaiden oletettua elinikää, mutta yksilökohtaisesti ne saattavat aiheuttaa vakavia, jopa kuolemaan johtavia komplikaatioita. Lopuksi työryhmämme osoitti ensimmäistä kertaa, että tehokkaalla lääkehoidolla pystytään ehkäisemään kaularankamuutosten kehittymistä varhaisvaiheen nivelreumassa.

Tulevaisuudessa tehokkaalla lääkehoidolla saatetaan pystyä ehkäisemään nivelreumaan liittyvien kaularankamuutosten kehittymistä myös pitkällä tähtäimellä, jolloin myös myöhäisvaiheen vaikeat vauriot ja niihin liittyvät komplikaatiot vähenevät.

The purpose of this thesis was to obtain information on the diagnostical procedures, prevalence, associating clinical factors, mortality and treatment of cervical spine disorders in rheumatoid arthritis (RA).

In the first study, the sensitivity of cervical spine radiographs taken in neutral position in the evaluation of anterior atlantoaxial subluxation (aAAS) was compared to the sensitivity of radiographs taken in flexion position. Using radiographs taken in neutral position aAAS was diagnosed only in 52% of patients who presented aAAS in radiographs taken in flexion. Moreover, the ability of neutral position radiographs to demonstrate the true extent of aAAS was significantly impaired, further indicating that cervical spine radiographs of RA patients should always be taken in flexion position of the neck.

The late prevalence of cervical spine changes was studied in 69 RA patients who were followed up for 20 years since the onset of the disease. aAAS, atlantoaxial impaction (AAI) and subaxial subluxation (SAS) were diagnosed in 23%, 26% and 19% of the patients, respectively. In addition, severe cervical spine changes with high risk for complications were recorded in approximately 10% of patients. Thereafter, the prevalence and severity of aAAS, AAI and SAS were compared with the occurrence and severity of peripheral and shoulder joint destruction, and bone mineral density (BMD) in the lumbar spine and femoral neck. Patients with aAAS or AAI presented significantly more erosions in peripheral, acromioclavicular and glenohumeral joints. In addition, the severity of atlantoaxial disorders (aAAS or AAI) positively correlated with the grade of destruction in the evaluated joints. Moreover, BMD of the femoral neck was significantly lower in patients with atlantoaxial disorders than in the other group. These results indicate that cervical spine disorders are common in longterm RA and patients with severe RA have an increased risk for cervical spine involvement. They also suggest that decreased BMD may influence the development of atlantoaxial disorders.

The mortality caused by cervical spine disorders was studied in RA patients who died in Finland during a period of one year. According to the death certificates, cervical spine disorders were not an official cause of death in any of these patients. However, a detailed examination of hospital records and cervical spine radiographs indicated that cervical spine disorders were poorly diagnosed in Finland in 1980:es, and in certain patients they most likely had resulted in life-threatening complications.

Finally, the efficacy of combination therapy with disease-modifying antirheumatic drugs (DMARDs) in the prevention of rheumatoid cervical spine changes was studied. One hundred ninety-five patients with recent-onset RA were randomly assigned to receive either a combination of DMARDs or a single-DMARD therapy. After two years follow-up the incidences of aAAS and AAI were 6.6% and 2.2% in the single-therapy group, respectively, whereas none of the patients in the combination-therapy group presented these disorders. The difference in the occurrence of aAAS between the two groups was statistically significant. In conclusion these results suggest that cervical spine disorders caused by RA can be retarded or even prevented with aggressive systemic drug therapy.