Background: The incidence rate of surgical treatment of cervical degenerative diseases (CDD) has increased in the USA and a large geographic variation has been shown. Little is known about such rates in Scandinavia and Europe. The aim of this population-based study was to (1) investigate annual incidence rates of operations performed in Norway, (2) to compare trends and variations in rates for surgical indications with and without myelopathy, and (3) to compare variations in the use of surgery between residential areas.
Methods: Patients operated for CDD and recorded in the Norwegian Patient Registry from 2008 to 2014 were evaluated according to residential areas (resident county and Regional Health Authority (RHA) area), age, gender, treating hospital, and whether myelopathy was present or not. Surgical rates were adjusted for age and gender. Data from private health care were also included.
Results: The annual surgical rates increased by 74.1 % from 2008 to 2014 (12.5/100,000 inhabitants). The largest increase was for surgical treatment of radiculopathy, 86.5 %. Surgical rates for CDD varied in 2014 with a ratio of 1.5 between the highest and lowest RHA and with a ratio of 2.5 between the different residential counties within one RHA. The treatment rates for myelopathy were relatively stable over time, but showed an increase of 2.1/100,000 (44.6 %) from 2013 to 2014.
Conclusions: Our study shows that the rate of surgical treatment for radiculopathy due to CDD has increased substantially from 2008 to 2014 for all RHAs in Norway. The incidence rate for surgical treatment of myelopathy was more stable. An unexplained and moderate geographic variation was found.
Keywords: Cervical degenerative disease; Geographic variation; Myelopathy; Radiculopathy; Surgery rates.