Decompression Alone Not Inferior to Decompression With Fusion for Spondylolisthesis

By Gene Emery

August 05, 2021

NEW YORK (Reuters Health) - Two years after patients with degenerative lumbar spondylolisthesis are treated with decompression surgery, those who skip spinal fusion do just as well as those who receive it, according to a new open-label noninferiority trial.

Using a 100-point index of impairment and modified intention-to-treat analysis, the study showed that an improvement of at least 30% occurred in 71.4% of patients without fusion versus 72.9% with fusion, a non-significant difference.

In the per-protocol analysis the rates were identical - 75.5% for each group.

The findings, published in the New England Journal of Medicine, mean that "most patients with spondylolisthesis should be treated with decompression alone as the first choice," chief author Dr. Ivar Austevoll of Haukeland University Hospital in Norway told Reuters Health by email.

"Results for secondary outcomes with respect to pain, disability, symptom severity, functional status, and satisfaction with treatment were generally in the same direction as those for the primary outcome," he and his team report.

In addition, blood loss was three times higher with fusion. Four fusion patients needed a transfusion versus none in the decompression-alone group. The rate of incidental dural tear was more than twice as high with fusion. Neurological deterioration was also more common.

All of the 267 randomized participants had not responded to at least three months of conservative management and had single-level spondylolisthesis of at least 3 mm. Eighty percent had suffered with back pain for more than a year; 75% had been dealing with leg pain for the same duration.

The findings could have a significant impact on practice because the United States spends about $13 billion a year on lumbar instrumented fusion procedures, more than any other surgical procedure, according to the Austevoll team. In some countries, more than 90% of patients who undergo surgery for their spine-related back and leg pain have a fusion.

Doctors tend to have strong opinions about which treatment is best.

"Interestingly, before starting the study, surgeons performing only decompression, as some neurosurgeons do, thought it was unethical to conduct the study due to the resistance to using screws, whereas surgeons performing decompression and fusion, as many orthopedic doctors do, thought it would be unethical to conduct the study due to resistance to not using screws," Dr. Austevoll said.

"We believe that some doctors will adapt to the new knowledge fast and some very slowly," he predicted. "Some will find reasons not well documented and subgroups of patients to reject the findings and continue to fuse the majority of patients with this condition."

Fusion added, on average, 70 minutes to the 104-minute operation and nearly two days to the three-day length of stay.

Among the 119 who didn't get fusion, 5.9% said their condition was "much worse" or "worse than ever" after the surgery. The rate in the fusion group was 5.0%, a non-significant difference.

A reoperation was needed in 12.5% of the decompression-alone group and 9.1% of those who also received fusion, also not a significant difference.

The study is known as NORDSTEN-DS. The team is planning follow-up studies, one of which is designed to probe whether specific patients or any subgroup of patients might benefit from fusion. The team will also follow the patients in the current study for 10 years.

Two other studies, both published in the Journal in 2016, gave conflicting conclusions about the benefits of adding fusion to decompression in such patients.

The study did not have commercial funding.

SOURCE: The New England Journal of Medicine, online August 4, 2021.