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Chapter 10
Intermittent neurogenic claudication (INC) is a complex of symptoms caused by lumbar spinal stenosis (LSS). Symptoms include leg pain, numbness of (frequently both) the legs and associated back pain. Usually patients will have a few months of conservative treatment before they are offered surgery. For over a century, bony decompression has been the gold standard. However, the present success rate of this gold standard is only 65%. New imaging techniques to improve patient selection and new treatment options to improve direct outcome have been developed. The main goal of new treatment options is to reduce the surgical extent in order to maintain the balance of the spine and to lower the risk of instability after the decompression. (Chapter 1) In 1986, a research group proposed a new technique in which an implant was placed between the spinous processes in order to indirectly decompress the spinal nerve roots and to unload the facet joints. Many similar devices have been developed over the past decades, but no biomechanical differences were demonstrated. Thousands of patients have since been implanted with these devices. Efficiency (not cost-efficiency) has only been demonstrated in comparison to conservative treatment. This thesis outlines the results of a double blind multicentre trial (the FELIX trial) in which an interspinous process device (IPDs) was compared with conventional bony decompression in the treatment of INC. Furthermore, we evaluated the diagnostic and prognostic value of MR images in patients with lumbar stenosis and INC.
Chapter 2 describes a national survey held among Dutch spine surgeons of their daily practice of patients with INC caused by LSS. The survey demonstrated a wide variety of Dutch spine surgeons’ preferred treatment of symptomatic LSS. To minimize variety, national and international protocols based on high-quality randomized controlled trials (RCT) and systematic reviews are necessary to give surgeons more tools to support everyday decision-making. Furthermore, over 30 percent of Dutch spine surgeons used IPDs (outside study protocol) in treatment for patients with INC.
The existing evidence on interspinous implant surgery was systematically reviewed in chapter 3. This systematic review did not include the results of the Felix Trial, because the review was done in 2011 before the publication of the Felix Trial (2013). Two independent RCTs and eight prospective cohort studies on patients with INC caused by LSS were available. In total 563 patients treated with IPDs were included. All studies showed improvement in validated outcome scores (patient satisfaction, disease specific questionnaires and leg pain) after six weeks and one year. Pooled data of the RCTs were more in favor of IPD treatment compared with
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