Low-back pain is a very common disease in Switzerland as elsewhere, wi
th a prevalence of 65%. The pain is usually due to degeneration of the
motion segment, but subsides spontaneously in some 95% of cases irres
pective of the treatment. Only 5% of patients still have pain after on
e year, but account for over 80% of the costs due to low-back pain. So
me patients can be helped by surgical fusion; however, preoperative id
entification of the pain source is mandatory. Since there is no consis
tent correlation between gain and the degree of degeneration ol: motio
n segments as seen on plain radiographs, functional radiographs, CT sc
an or MRI, other diagnostic methods such as facet blocs, discography a
nd external diagnostic fixation must be used. After careful patient se
lection a fusion operation may be considered. Good results after fusio
n operations are reported in 60-80% of patients. The operative techniq
ues are described.