Effectiveness of surgery for people with leg or back pain due to symptomatic spinal stenosis

Cochrane: How well do different types of surgery work for lumbar spinal stenosis? Spinal stenosis is the narrowing of the spinal canal in the lower back region caused by thickening of the soft tissues and bones. It is a common condition for which surgery is usually performed after non-surgical treatments (such as physiotherapy) have failed to bring sufficient relief to patients. Spinal stenosis is a common cause of low back pain that radiates to the legs, and it is more common in older adults. Surgery for lumbar spinal stenosis normally involves taking pressure off the spinal cord or spinal nerves (known as decompression) by removing bone and soft tissues from around the spinal canal. Another common surgical approach is to fuse two or more vertebrae together after decompression in the patient whose spine seems to be unstable.
The usefulness of some types of surgery for lumbar spinal stenosis, however, has been questioned, and previous studies have reported that patients who receive fusion are more likely to have major complications and higher costs when compared with patients who undergo decompression only. More recently, spinal implants were created to help indirectly reduce pressure in the spinal canal and at the same time stabilise the bones. However, these implants have also been linked to worse outcomes (e.g., higher reoperation rates) when compared to conventional decompression.
Search date
This review includes all trials published up to June 2016.
Study characteristics
We included all trials that compared any surgical technique with no surgery or placebo surgery, and also trials comparing different surgical techniques with each other, including fusion and spinal implants. All the patients included in these studies were diagnosed with lumbar spinal stenosis and had symptoms in the leg or thigh that worsened by walking or standing and were generally relieved by a change in position, such as bending forward or sitting. The main measure we used to compare how well the different types of surgery worked was how much less pain people felt as they went about their daily lives. We also looked at whether their leg pain improved, how much blood they lost during surgery, how long the surgery took, how long they had to stay in hospital, how many patients had to have another operation for the problem and how much the treatment cost.
Key results and quality of the evidence
Twenty-four randomised controlled trials were included with a total of 2352 people. We did not find trials that compared surgery with no treatment or placebo surgery, so all included trials compared different surgical techniques. The quality of the evidence from these studies varied from very low quality to high quality. This large variation was mainly due to different study protocols, surgical techniques and quality of reporting according to the 'Risk of bias' assessment. We found that patients who had decompression plus fusion fared no better than those who underwent decompression surgery alone. In fact, decompression plus fusion resulted in more blood loss during surgery than decompression alone. Although the spinal spacers were slightly better than decompression plus fusion in terms of improvements on daily activities, there were no differences when they were compared with decompression alone. Finally, we found no differences between different forms of decompression.

Authors' conclusions: 

The results of this Cochrane review show a paucity of evidence on the efficacy of surgery for lumbar spinal stenosis, as to date no trials have compared surgery with no treatment, placebo or sham surgery. Placebo-controlled trials in surgery are feasible and needed in the field of lumbar spinal stenosis. Our results demonstrate that at present, decompression plus fusion and interspinous process spacers have not been shown to be superior to conventional decompression alone. More methodologically rigorous studies are needed in this field to confirm our results.