Higher rates of reoperation with interspinous spacer


A new study indicates that the use of the interspinous spacer X-Stop (Medtronic) in spinal stenosis patients with neurogenic claudication is associated with a higher rate of reoperation compared with the rate associated with decompressive surgery. However, the patient-reported outcomes were similar for both treatment approaches.

Reporting the results of the study at the annual meeting of the International Society for the Advancement of Spinal Surgery (ISASS; 3–5 April, Vancouver, Canada), Björn Strömqvist, Skane University Hospital, Orthopedics, Lund, Sweden, stated that previous studies have shown that the X-Stop device has significantly better outcomes than non-operative management in patients with lumbar spinal stenosis. He added that, unlike open surgery, the device is inserted under local anaesthetic and patients are discharged from hospital the day after surgery (it might also be performed on out-patient basis).

Furthermore, Strömqvist said that its implantation carries no risk for nerve or cauda equina injury in contrast to open surgery. However, it has not been compared with decompressive surgery (the gold standard treatment for lumbar spinal stenosis) in a randomised controlled trial. Thus, the aim of the present study, Strömqvist reported, was: “To compare X-Stop to decompressive surgery for lumbar spinal claudication [as a result of spinal stenosis].”

To be enrolled in the study, patients had to have spinal stenosis at one or two levels (verified by MRI) and neurogenic claudication (spinal claudication relieved by flexion). After randomisation by envelope, 50 patients received the X-Stop device (average age 67; 30 males) and 50 received conventional decompressive surgery (average age 71; 26 males). The primary outcome measure was the Zürich Claudication Questionnaire (ZCQ; symptom severity, physical function, and patient satisfaction) and secondary outcome measures included the Visual Analogue Scale (VAS) leg and back pain scores, the SF-36 questionnaire, complications, and reoperations.

After 24 months of follow-up, there were no significant differences in any of the ZCQ scores or in any of the VAS scores between the groups. There were also no differences in these factors at six months or at one year. However, there were significantly more reoperations in patients who received the X-Stop device compared with those who underwent decompressive surgery (13 vs. 3, respectively; p<0.01). According to Strömqvist, the results were identical “irrespective of whether intention-to-treat or as-treated results were analysed”. He added: “This means that patients with failed X-Stop surgery reoperated with decompression showed identical outcome with those with ‘primary decompression’. For lumbar spinal stenosis with neurogenic claudication, decompressive surgery and X-Stop are rewarding procedures.”

Strömqvist told Spinal News International that an “absolute prequisite” for using the device was that patients had to be “more or less totally symptom-free when sitting down or flexing the spine”. He added: “The X-Stop may be especially useful in elderly patients, who are risky candidates for surgery under general anaesthesia, but perhaps also young patients with typical symptoms where the surgeon might be hesitant about performing decompressive surgery if symptoms are not severe enough”.