Purpose: The incidence of surgery for lumbar disc hernia varies. According to the national
spine registries in Sweden, Norway and Denmark, there is a 30-60% difference in surgical
incidence between these countries. The cause for this difference is not known. It may reflect
a difference in incidence of lumbar disc hernia, but with a similar socio-economic and
ethnical background in these countries, it is more likely that the differences are due to
varying surgical indications. Comparing indications for surgery, patient reported outcome and
factors predictive for outcome after surgery for lumbar disc hernia in these countries could
provide information about optimal indications for surgery.
Hypotheses: (i) there are no differences in patient-reported outcome after surgery between
these countries, (ii) there are no differences in indications for surgery between these
countries and (iii), factors that predict outcome are similar in these countries.
Method of research: By using data from three Nordic national spine registers, we will compare
baseline data, indications for surgery and patient reported outcome one year after surgery
for lumbar disc herniation. Register based studies have advantages such as large sample
sizes, reflecting real life, but they also have limitations such as lower follow-up rates
than clinical trials. A non-response analysis will be performed to take this into account.