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Swedish Lumbar Spine Study group released midterm results
Improvements at early follow-up sustained at five to 10-years' follow-up.
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PORTO,
Portugal — Intermediate results of the Swedish Lumbar Spine Study showed
that the improvements seen at early follow-up in patients who had fusion
surgery were sustained through the five- to 10-year follow-up.
The Swedish Lumbar Spine study is a randomized controlled trial that compares results in patients with chronic low back pain (CLBP) treated with surgery or nonsurgical interventions.
“Our conclusion is that there may be what we could call a ‘time gain’ by [using] fusion surgery for patients with CLBP,” said Olle Hägg, MD, of Gothenburg, Sweden, who reported midterm results here at SpineWeek 2004.
When asked how long the time gain with fusion may last, Hägg could not say since no follow-ups were conducted between two and five years’ postop.
In the study, fusions performed at L4-L5 and/or L5-S1 in patients with CLBP led to improvement in pain, function and disability at the two-year follow-up in 63% of patients, which was not seen in control patients, where only 29% showed improvement.
Fusion effect
Based on the latest data obtained from questionnaires mailed to patients, this effect from fusion surgery was sustained through the recent follow-up, with 57% of fusion patients and 53% of physiotherapy patients reporting an improvement at a mean follow-up of 6.5 years.
The mean Oswestry Disability Index (ODI) scores at both time periods demonstrated interesting trends, according to Hägg. Baseline scores were 27 in the surgery group and 29 in the physiotherapy group. “After two years, there was significant improvement in both groups, but there was a significant difference in favor of surgery. When you get to five to 10 years there is still improvement in the surgical group, but the control group has caught up,” Hägg said.
At intermediate follow-up, there was slightly increased pain in the fusion group based on increased Visual Analog Scale (VAS) scores, “but mainly an improvement in the control group,” he said. The fusion group’s VAS scores increased to 48 from 43 at two years, and the control group’s scores were 44 vs. 58 at two years. The differences between the groups were not significant.
There were no significant differences in the results with posterolateral instrumented, uninstrumented or instrumented 360° fusion surgery based on ODI or VAS scores.
Dropouts concerning
Thirty-nine patients in the surgery group and 22 patients in the control group dropped out of the study. To rule that out as a factor affecting results, investigators controlled for it in a worst-case analysis and found “a significant improvement at five to 10 years in favor of the control group.” A best-case analysis, however, yielded improvements favoring the surgical group.
“The possible bias of dropouts does not seem to significantly change the results in the surgery group, whereas it may make the data in the control group somewhat unsure,” Hägg said.
For more information:
- Fritzell P, Hägg O, Nordwall A, et al. 5-10 years follow-up in the Swedish Lumbar Spine Study. #A125. Presented at SpineWeek 2004. May 31-June 5, 2004. Porto, Portugal.