Surgical treatment of Lumbar Spinal Stenosis: X-stop vs Minimally Invasive Decompression Image assessment, treatment effects and health economic evaluations

摘要

This dissertation is based on a randomized controlled Norwegian multicenter study and focusesudon diagnosis and treatment of lumbar spinal stenosis (LSS), which is the most common reasonudfor spinal surgery among the elderly. As new medical technology has improved, so has theuddiagnostic and treatment options. Imaging has gone from x-ray via CT scan to MRI, the trendudwithin surgery over the last two decades has gone from laminectomy with larger incisions toudminimally invasive decompression. A new treatment method has been introduced as interspinousudprocess decompression (IPD). In 2005, X-stop became the first IPD device to be approved by theudUS Food and Drug Administration (FDA). The aims in this study were to compare X-stop toudwhat is regarded as the gold standard, namely minimally invasive decompression. We wanted toudassess the image evaluation done prior to the operative treatment and ascertain whether X-stop orudminimally invasive decompression provides the best clinical outcome and health economicudefficacy two years after treatment.udIn this study 96 patients were included for randomization. Eligible patients were aged 50–85udyears and exhibited symptoms of neurogenic intermittent claudication within 250 meters walkinguddistance for at least six months. Symptom relief through spinal flexion was an inclusion criterion,udsince this was a necessary indication for the use of X-stop. Preoperative images from 84 patientsudwere available for the first paper; 81 patients completed the two-year follow-ups and wereudrandomized to either X-stop (n = 40) or minimally invasive decompression (n = 41). Due to theudsignificant reoperation rate in the X-stop group, the study was terminated after a midway interimudanalysis. udIn the first study, we compared two different ways of assessing LSS on preoperative axial viewudvia MRI and found the inter- and intraobserver agreements of area measurement andudmorphological grading A–D to be acceptable. The intercorrelation between the methods wasudstrong, and both methods may be used in the MRI evaluation of LSS.udThe second study showed that both X-stop and minimally invasive decompression led toudsignificant symptom improvements. There were no significant clinical differences in effectudbetween the methods at any of the follow-up time points, yet X-stop had a significantly higherudrate of secondary surgery. The risk of surgical complications was equal in both groups, but moreudsevere for minimally invasive decompression group.udComparing cost-effectiveness of X-stop to minimally invasive decompression in the third studyudrevealed an incremental cost-effectiveness ratio (ICER) of € 25,700, which means that there wasuda 50% likelihood that X-stop is cost-effective at the additional price for a quality-adjusted lifeyearud(QALY) compared to minimally invasive decompression. The difference in effect wasudinsignificant. The significantly higher cost of X-stop is mainly due to implant cost and theudsignificantly higher reoperation rate.udWe concluded that both methods had significant effect at all follow-ups, and that there were nouddifferences in effect between the methods. X-stop was significantly more expensive. Highudreoperation rate in the X-stop group is a clear disadvantage with this method, although minimallyudinvasive decompression has a potential for more severe complications.