Within 10 years, it is estimated that 64 million older adults will be afflicted with lumbar spinal stenosis, making it the most common indication for spine surgery in individuals older than 65 years. [1,2] This expanding population of patients requires a greater range of treatment options throughout the continuum of care, particularly in the elderly who may not be appropriate candidates for open surgical procedures with the associated risks of general anesthesia. Interspinous process decompression (IPD) is a minimally invasive procedure that can be performed under monitored anesthesia care in an ambulatory surgery center and has been shown to provide comparable clinical performance to decompressive laminectomy for management of symptoms of spinal stenosis. [4,5]
Stand-alone interspinous spacers are designed for the treatment of symptoms of intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis, and are implanted by minimally invasive methods through a cannula. In contrast to direct surgical procedures, such as decompressive laminectomy, where the soft and bony tissues compressing the neural elements are surgically removed through an open operative exposure, spacers provide minimally invasive, indirect decompression of spinal nerves, and function by serving as a spinal extension blocker to prevent compression of neural elements in extension without the removal of tissue adjacent to the nerves.
Figure 1 depicts the implant in its final position after placement between the spinous processes. Figure 1: Superion® InterSpinous Spacer in situ Lateral View A/P View The Superion® ISS can generally be described in two (2) “states”: Undeployed (closed), and deployed (open). The implant is supplied in the undeployed state, and it is in this form that it is passed through a delivery cannula placed at midline, to the implantation site. Once delivered to, and located in, the interspinous space between the spinous processes at the selected level, the Superion® ISS is deployed to open the superior and inferior cam lobes. In doing so, these cam lobes rotate 90° from the implant axis to engage the lateral aspects of the superior and inferior spinous processes posterior to the lamina. Figure 2 provides views of the implant as it transitions from the closed to open (or deployed) configuration. Figure 2: Superion® ISS in Closed and Extended (Deployed) Position
The device may be implanted under general, or local (e.g., conscious sedation) anesthesia. The patient is placed prone with the spine in a flexed position. A percutaneous or mini-open approach is used for incision and placement of the cannula via sequential dilation, to allow cannula positioning in the interspinous space. Once the cannula is in place, a sizing tool is employed to determine the proper device size. The Superion® ISS is then inserted through the cannula and deployed under fluoroscopic guidance between adjacent vertebral spinous processes at the level to be treated. The insertion instrumentation is then removed, leaving the implant in place. The rigid implant serves thereafter to maintain the desired distraction between the spinous processes while still preserving motion. This maintains the intervertebral space and prevents narrowing of the canal by limiting extension at that level. Where a second, contiguous level is also symptomatic, the same procedure is used to place a Superion® ISS at that level.
The Superion® InterSpinous Spacer is intended to treat skeletally mature patients suffering from pain, numbness, and/or cramping in the legs (neurogenic intermittent claudication) secondary to a diagnosis of moderate degenerative lumbar spinal stenosis, with or without Grade 1 spondylolisthesis, confirmed by X-ray, MRI and/or CT evidence of thickened ligamentum flavum, narrowed lateral recess, and/or central canal or foraminal narrowing. The Superion® ISS is indicated for those patients with impaired physical function who experience relief in flexion from symptoms of leg/buttock/groin pain, numbness, and/or cramping, with or without back pain. The Superion® ISS may be implanted at one or two adjacent lumbar levels in patients in whom treatment is indicated at no more than two levels, from L1 to L5.
The Superion® Interspinous Spacer is contraindicated in patients with: • an allergy to titanium or titanium alloy; • spinal anatomy or disease that would prevent implantation of the device or cause the device to be unstable in situ, such as: • significant instability of the lumbar spine, e.g., isthmic spondylolisthesis or degenerative spondylolisthesis greater than grade 1.0 (on a scale of 1 to 4); • an ankylosed segment at the affected level(s); • acute fracture of the spinous process, pars interarticularis, or laminae fracture (unilateral or bilateral); • significant scoliosis (Cobb angle >10 degrees); • Cauda equina syndrome defined as neural compression causing neurogenic bladder or bowel dysfunction; • diagnosis of severe osteoporosis, defined as bone mineral density (from DEXA scan or equivalent method) in the spine or hip that is more than 2.5 S.D. below the mean of adult normals in the presence of one or more fragility fractures; • active systemic infection, or infection localized to the site of implantation.
The minimally invasive nature of the Superion® surgery and smaller overall device size are novel, compared to both indirect and direct decompression options. This procedure provides lower patient morbidity than open direct surgical decompression, with or without additional stabilization, while offering comparable effectiveness in relieving symptoms. This conservative surgical option offers a benefit to patients whose overall health and existing co-morbidities preclude, or put them at increased risk of complications associated with a larger decompressive surgery. Surgeries requiring decompression or decompression with fusion also carry greater risk for adverse events, and recovery time is significantly longer, generally requiring extended hospital, post-surgical care and return to activities of daily living. In addition, the device implantation procedure imposes no alteration of the spinal anatomy, thereby preserving potential future surgical options in the event of spinal disease progression. In comparison, direct decompression surgery can introduce spinal instability and require more serious interventions, such as spinal fusion, if the initial decompression is ineffective.
There are ways to treat your moderate lumbar spinal stenosis. Some are:
Discuss your options with your doctor and select the treatment method that best seems to meet your current pain level and lifestyle.
To be a candidate for treatment with the Superion® Spacer:
Surgical Site Care:
Most surgical site wounds will have a few stitches or staples that should be kept clean and dry until the first follow-up visit usually scheduled in 7 to 14 days.
All patients have different needs therefore it is important to always follow the treating physician’s instructions regarding recommended activity restrictions. For 6 weeks, limit all lifting, bending and strenuous activity including:
Increase your light activity, such as walking, as tolerated.
Ask your physician regarding further recommended activity restrictions at your first follow-up visit.
 Lauryssen C, Jackson RJ, Baron JM, et al. Stand-alone interspinous spacer versus decompressive laminectomy for treatment of lumbar spinal stenosis. Expert Rev Med Devices. 2015;12(6):763–769.
 Nunley PD, Shamie AN, Blumenthal SL, Orndorff D, Block JE, Geisler FH. Interspinous process decompression: expanding treatment options for lumbar spinal stenosis. Biomed Res Int. 2016;2016:3267307.
 www.tandfonline.com 10.1586/17434440.2015.1100071 © 2015 Taylor & Francis ISSN 1743-4440 1 Special Report