- Department of Neurological Surgery, The Albert Einstein College of Medicine, Bronx, NY, 10467, and Chief of Neurosurgical Spine and Education, Winthrop University Hospital, Mineola, NY 11501, USA
Nancy E. Epstein
Department of Neurological Surgery, The Albert Einstein College of Medicine, Bronx, NY, 10467, and Chief of Neurosurgical Spine and Education, Winthrop University Hospital, Mineola, NY 11501, USA
DOI:10.4103/2152-7806.92172Copyright: © 2012 Epstein NE. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Epstein NE. A review of interspinous fusion devices: High complication, reoperation rates, and costs with poor outcomes. Surg Neurol Int 21-Jan-2012;3:7
How to cite this URL: Epstein NE. A review of interspinous fusion devices: High complication, reoperation rates, and costs with poor outcomes. Surg Neurol Int 21-Jan-2012;3:7. Available from: http://sni.wpengine.com/surgicalint_articles/a-review-of-interspinous-fusion-devices-high-complication-reoperation-rates-and-costs-with-poor-outcomes/
Background:Interspinous fusion devices (IFDs) are increasingly offered to patients over the age of 50 with lumbar spinal stenosis and intermittent neurogenic claudication. Here, we review the literature on complication rates, reoperation rates, and outcomes for implanting IFD, and offer an assessment of IFD charges at a single institution in 2010.
Methods:The literature concerning IFD implants was reviewed with particular attention focused on complications, reoperation rates, and outcomes. Additionally, the costs of implanting 31 IFD devices in 16 patients at one to three levels at a single institution in 2010 are presented.
Results:Reviewing the spinal literature concerning the postoperative status of IFD followed over an average of 23–42.9 postoperative months revealed that IFD resulted in 11.6–38% complication rate, 4.6–85% reoperation rate, and 66.7–77% frequency of poor outcomes. Additionally, the 31 devices implanted in 16 patients at a single university hospital in 2010 cost a total of $576,407.
Conclusions:With high maximal complication rates (38%), reoperation rates (85%), poor outcomes (77%), and high costs ($576,407 for 31 devices in 16 patients), the utilization and implantation of IFD remains extremely controversial and should be investigated further.
Keywords: Complications, high costs, interspinous fusion devices, lumbar stenosis, poor outcomes, reoperations
Multiple interspinous fusion devices (IFDs), including the X-STOP (Medtronic, Memphis, TN, USA), have been utilized to treat older patients (age 50 and over) with lumbar spinal stenosis and intermittent neurogenic claudication. The Food and Drug Administration (FDA) has approved the implantation of IFD in the lumbar spine at one or two levels. Here, we review the complication rates, reoperation rates, and outcomes for IFD utilized to treat lumbar stenosis. We also include an assessment of the charges for implanting these devices at a single institution in 2010.
The FDA approved the X-STOP IFD (originally St. Francis Medical Technologies Inc., Alameda, CA, USA) on November 21, 2005 (for Medtronic Spine LLC; P04001) as follows: “Approval for the X-STOP interspinous process decompression system (Internet Site: X-STOP(R) IPD(R) System Risk Management Statement-Medtronic). The device is indicated for treatment of patients aged 50 or older suffering from neurogenic intermittent claudication secondary to a confirmed diagnosis of lumbar spinal stenosis (with X-ray, MRI, and /or CT evidence of thickened ligamentum flavum, narrowed lateral recess and/or central canal narrowing). The X-STOP is indicated for those patients with moderately impaired physical function who experience relief in flexion from their symptoms of leg/buttock/groin pain, with or without back pain, and have undergone a regimen of at least 6 months of nonoperative treatment. The X-STOP may be implanted at one or two lumbar levels in patients in whom operative treatment is indicated at no more than two levels.”
Contraindications to the X-STOP device included “allergy to titanium or titanium alloy, spinal anatomy that prevents implantation due to significant instability, ankylosis, acute fracture of the spinous process or pars interarticularis, significant scoliosis, neural compression causing neurogenic bowel or bladder dysfunction, severe osteoporosis, and active systemic infection at the locale of potential device implantation” (Internet Site: X-STOP(R) IPD(R) System Risk Management Statement-Medtronic).
IFD devices biomechanically limit extension and increase flexion, thereby enlarging the spinal canal and neural foramina at stenotic levels.[
Few high-quality studies adequately analyze the safety and efficacy of the X-STOP IFD.[
In six studies involving a total of 384 cases (range 12–175 per study), implanting IFD devices correlated with various complications rates, reoperation rates, and poor outcomes.[
Complications of interspinous fusion devices
The overall complication rate for implanting IFD ranged from 11.6 to 38%.[
In the second study utilizing 50 IFD devices [34 X-STOP Titanium and 8 X-STOP polyether ether ketone (PEEK; Medtronic), and 8 Lanx Aspen (Lanx, Inc., Broomfield CO, USA)] implanted in 38 patients (26 at L4–L5, and 12 at L3–L4/L4–L5), the frequency of spinous process fractures documented on CT but missed on X-ray was 22% (11 patients).[
In the third study involving 69 patients treated with the X-STOP (46 one-level and 23 two-level procedures) and followed for an average of 23 months, 8 (11.6%) patients developed device-related complications: 4 device dislocations and 4 spinous process fractures.[
In the fifth study, a case report, an 84-year-old male underwent the initial placement of an X-STOP device at an outside institution at the L4–L5 level. This resulted in an immediate postoperative bilateral foot drop.[
High reoperation rates attributed to interspinous fusion devices
Reoperation rates ranged from 4.6% to as high as 85% following the placement of IFD/X-STOP devices.[
Poor outcomes of interspinous fusion devices
Poor outcomes, defined by recurrent pain, were observed in from 66.7–77% of cases.[
In Rolfe et al.'s study involving 179 consecutive patients, higher degrees of scoliosis correlated with poorer outcomes following the placement of X-STOP devices.[
Burnett, Stein, and Bartels performed a structured literature review of conservative treatment, decompressive laminectomy, and X-STOP placement in patients with lumbar stenosis, utilizing quality-adjusted life years along with costs at 2 years following surgery.[
At our institution in 2010, involving 16 patients averaging 71 years of age, 7 males and 9 females received 31 X-STOP devices. Four surgeons implanted these devices at from one to three levels; seven patients had one-level devices, three patients had two-level devices, and six patients had three-level devices (not FDA approved) implanted [
Within up to four postoperative years, IFD devices, including the X-STOP, utilized to treat lumbar stenosis in patients over 50 years of age resulted in up to a 38% complication rate, up to an 85% reoperation rate, and up to a 77% incidence of poor outcomes.[
I would like to thank Professor Donald C. Hood for his conceptual recommendations and Ms. Sherry Lynn Grimm for her editorial assistance.
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