Lumbar instability and clinical symptoms: which is the more critical factor for symptoms: sagittal translation or...

The relationship between radiologic instability and its symptoms is controversial. Previous authors consider flexion-extension radiographs to be of little value in evaluating instability; however, the current authors consider the variation of results in evaluating radiologic instability to be the result of limitations in previous researchers' methods.

In this report, sagittal translation and angulation at the L4-L5 segment were measured in flexion-extension films in 1,090 outpatients with low back and/or leg pain using a three-landmark measuring method. The symptoms of four groups with and without 3-mm translation and with and without 10 degrees angulation were compared for all the patients and for 280 age-matched patients using a scoring system. The age-matched patients were followed up for 4.6 years.

Results showed that patients with > or = 3-mm translation had significantly lower scores, indicating a limitation in their daily activities due to pain, than patients < 3-mm translation; however, no difference was observed between the groups in terms of angulation. The group with > or = 3-mm translation and > or = 10 degrees angulation significantly demonstrated the lowest scores at both evaluations during the initial visit and follow-up. This group had been suffering from low back and/or leg pain the longest and had visited the hospital significantly more often than other groups.

In conclusion, translation of the lumbar segment has a greater influence than angulation on lumbar symptoms. The presence of both radiologic factors could be an indicator for persistence of the symptoms.