Central lumbar spinal stenosis: natural history of non-surgical patients

The aim of the present study was to examine the natural history in patients with lumbar spinal stenosis. The incidence of surgery for this condition has increased considerably during the past decades in spite of a fairly favorable natural history in previous studies.

146 consecutive patients with clinical signs and image findings of lumbar spinal stenosis, who were not recommended surgical treatment, were followed; the reason as to why surgery was not recommended was a moderate symptom level. The follow-up rate was 89% after 3.3 years. Group values for comorbidities and diagnostic imaging were comparable to patients selected for surgery, with the exception of a lower frequency of degenerative spondylolisthesis among the non-operative patients. The mean age of those observed was 68 (21-91), and 58% were females.

During the observation period spontaneous improvements were found for pain and health-related quality of life, but not for walking. Using the minimum clinically important difference for VAS, leg and back pain improved in 32 and 36% of patients, respectively, were unchanged in 55 and 54%, and worsened in 13 and 10%. Findings on diagnostic imaging did not influence patient outcome, except for stenoses with cross-sectional area <0.5 cm² where spontaneous improvement was not seen. Revision of the decision not to operate occurred in 10 cases (7%).

The natural history of LSS with moderate symptom levels rarely shows symptom deterioration over a median of 3.3 years; in fact, a slight improvement of symptoms was seen at group levels. The treatment decision was revised for 7%, and for the rest an increase in pain was seen in 10-13%. The results support reluctance towards surgery, if the symptom levels are tolerable for the patients.