A recent study that tracked the one year follow-up results of patients with lumbar spinal stenosis demonstrated that the Minimally Invasive Lumbar Decompression (MILD) procedure, an alternative to open laminectomy, reduces pain and morbidity with no serious adverse events. This is one of the first research studies demonstrating the effectiveness and safety of the MILD procedure, which is a budding alternative to traditional, open laminectomy. Findings presented at a session of the American Academy of Pain Medicine earlier this week assessed the results of the MILD procedure in 58 patients, representing 170 procedures, 1 year after surgery. The average patient age was 70 and most of the procedures were performed bilaterally, at 1 or 2 affected spine levels. The researchers used four metrics, namely the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), and the 12-item Short-Form Health Survey (SF-12v2), to track outcomes in the 58 patients.
At one-year follow-up, patients' pain scores fell by 40 percent. VAS scores went from a mean of 7.4 to 4.5, representing 79 percent improvement. ODI scores improved for 71 percent of the subjects, from a mean of 48.6 to 36.7 at one year post surgery. The ZCQ and SF-12v2 scores also improved, signifying decreased pain and enhanced physical function. The principle researcher, Dr. Deer, noted that while open surgery is associated with 20 percent adverse events, the MILD procedure in this study did not lead to hematoma, dural tears, nerve root damage, or need for blood transfusions.
The MILD procedure, marketed by Vertos, is a minimally invasive technique for treating lumbar spinal stenosis in patients who have failed conservative therapy but who have not undergone open surgery. MILD received 510(k) approval in 2006. During this outpatient procedure, access to the spinal canal is achieved percutaneously with the aid of fluoroscopy. Once the guidance needle reaches the interlaminar space, a cutting device is used to remove tissue and bone in order to decompress the part of the lamina where the disc collapsed. The surgeon then inserts a proprietary sculpting tool to reduce the size of the expanded ligament, which caused the nerve compression and pain. In traditional, open laminectomy, the entire ligament and bone causing the nerve compression is removed, whereas MILD only targets the portion of the tissue that is causing the compression. Medtronic's X-STOP interspinous process spacer also positions itself as a less invasive alternative to laminectomy due to its preservation of bony tissue; however, the X-STOP is an implantation, whereas MILD does not require any implant.
This study has key strengths in research design. Since the study was performed prospectively, metrics were measured in real-time, which removed any recall biases or other issues associated with retrospective data collection. Additionally, unlike many other studies, this research followed 4 metrics, thereby measuring several factors such as pain improvement, adverse events, and physical function. One major caveat to this study is that it does not compare MILD to open, traditional laminectomy. Therefore, while MILD has been shown to be safe and effective in reducing pain and improving physical activity, these results do not indicate that MILD is more effective than laminectomy. Additional studies should be performed, where MILD and traditional laminectomy are directly compared, to investigate whether one method is more effective.
In recent years, the spine product market has exploded with a myriad of products that further surgical options for patients. A multitude of motion-preservation technologies in particular have been introduced due to the ease in developing them, patient's preference for retaining motion, and physician preference due to ease in use over minimally invasive fusion techniques. In the last week however, the Food and Drug Administration (FDA) issued a warning letter to Alphatec Spine, manufacturer of motion preservation spine products, for violating post-market study requirements.
Alphatec Spine currently has three dynamic stabilization devices, namely the Isobar semi-rigid dual dampener, Zodiac DynaMo semi-rigid spinal system, and Isobar semi-rigid spinal system, approved by the FDA under 510(k) status in 2008, 2007, and 1999, respectively. In October 2009, the FDA ordered Alphatec and 15 other companies with dynamic stabilization/motion preservation technologies to perform post-market studies to track the safety and efficacy of the products under section 522 of the Food, Drug, and Cosmetic Act. Citing insufficient clinical data to determine whether motion-preservation technologies can indeed achieve stable fusion, the FDA issued 522's that requested additional study information within a specific time frame so that post-market surveillance on the products could be performed. Specifically, the FDA requested information on:
- Dynamic stabilization vs. traditional techniques in achieving fusion
- Accounts of any adverse events
- Time and incidence rates of dynamic stabilization surgery vs. traditional surgery
- Accounts of failure of dynamic stabilization systems
Since Alphatec failed to provide the necessary data, the FDA has issued a warning letter that declares that the three Alphatec products are misbranded. It is uncertain whether the FDA intends to send similar warnings to the 15 other companies, which include DePuy, Medtronic, Zimmer, and Synthes, that may not have delivered clinical data.
Regardless, this action represents an increased focus on enforcing safety and efficacy through clinical data. In the past, the FDA has requested additional clinical data from vendors but has not invested resources in enforcing these requests or following-up on data. However, the FDA (as well as academic societies and insurance payers) have recently started cracking down more stringently on spine technologies. With increasing studies demonstrating the ineffectiveness of certain products and surgeries, the utility in demonstrating the value of spine surgery has become paramount. For example, the American Academy of Orthopedic Surgeons (AAOS) discouraged the use of vertebroplasty for vertebral compression fractures in September 2010 after randomized, clinical studies demonstrated it as ineffectual and comparable to sham procedures. In this same vein, the FDA is signaling the importance of verifying the outcomes from using different spine technologies by issuing these fairly rare 522 study requirements.
Readers of the Pipeline will have seen recent posts on vertebral augmentation (kyphoplasty and vertebroplasty), which highlighted the arrival of new technologies while also showing the clinical uncertainty of treating lower back pain originating from vertebral compression fractures with these procedures. This week in Orlando, Technology Insights is attending the North American Spine Society's 25th annual meeting; because of all the recent controversies in vertebral augmentation, we're keeping our eyes open for the reactions of experts and industry.
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A few weeks ago the Wall Street Journal reported that spine device manufacturers had commented during quarterly earnings calls that pressure from major insurance companies was limiting spinal surgeries and thereby negatively impacting these companies sales figures. The article cited a number of efforts by WellPoint, Aetna, and UnitedHealth, to curtail the growth in expensive spinal surgery cases, particularly lumbar fusion. These efforts, which included pre-authorization and the 'soft' influence of doctor-led dialogs concerning appropriate spinal care, work under the assumption that spinal surgery is being overused and more conservative treatment patterns may be better from both a clinical and cost-effectiveness perspective.
A few days later the Star Tribune reported on the controversies surrounding spine surgery while telling the story of a woman who had refused surgery and instead endured a series of twenty-four intense rehab sessions, to overall favorable results.
This pair of stories comes at an interesting time in the national debate about health care. While hospitals are increasingly concerned about declining reimbursements, payers (especially the government) are looking to pay less for a higher quality of care. In this environment, treatment for back pain may come under increasing scrutiny. With a high incidence and prevalence--it's estimated that half of working Americans have back pain each year and that nearly eighty percent of all people worldwide will suffer from back pain at some point in their lives--the cost of providing care to such a population is immense.
Recently, Technology Insights has been refreshing all of our research on spine care, working to understand how these national changes may impact future delivery systems, the increasing role and importance of pain management in orthopedics and spine care, and of course how innovations in technology may change treatment options. We believe these questions will become increasingly important as rules and guidelines around accountable care come into light and will continue to keep our members updated.