A misreading of the evidence?

In their reply to rapid responses about the guideline from the National Institute for Health and Clinical Excellence (NICE) on persistent non-specific low back pain,1 Underwood and Littlejohns say that two systematic reviews report that spinal fusion is effective and informed the NICE low back pain guideline development group2; the group proposes referral for consideration of spinal fusion as an appropriate step in managing low back pain of less than 12 months’ duration.

However, the authors of the first review say:

Surgical fusion for chronic low back pain favoured a marginal improvement in the Oswestry Disability Index (4.13) compared to non-surgical intervention. This difference … was not statistically significant and is of minimal clinical importance. Surgery was found to be associated with a significant risk of complications (16%). Therefore, the cumulative evidence at the present time does not support routine surgical fusion for the treatment of chronic low back pain.3

An erratum has since been published, a repeat meta-analysis because of incorrect interpretation of one randomised controlled trial modifying the results.4 The authors conclude, however, that the improvement in the Oswestry disability index compared with the original article (−4.87 v −4.13) was significant but of minimal clinical importance and that more study is needed to provide more conclusive evidence in favour of either treatment.

The authors of the second review, of four randomised controlled trials,5 reached similar conclusions. They state that one study suggested greater improvement in back specific disability for fusion compared with unstructured non-operative care at two years, but the trial did not report data according to intention to treat principles. Also, three trials suggested no substantial difference in disability scores at 1 year and 2 years when fusion was compared with a three week cognitive behaviour treatment addressing fears about back injury.

For Underwood and Littlejohns to say that these reviews report spinal fusion to be effective is disappointing and suggests a misreading of the evidence.