Superion™ Indirect Decompression System - Indications for Use
INDICATIONS FOR USE
The Superion Indirect Decompression System is indicated to treat skeletally mature patients suffering from pain, numbness, and/or cramping in the legs (neurogenic intermittent claudication) secondary to a diagnosis of moderate 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 IDS is indicated for those patients with impaired physical function who experience relief in flexion from symptoms of leg/buttock/groin pain, with or without back pain, who have undergone at least 6 months of non-operative treatment. The Superion IDS may be implanted at one or two adjacent lumbar levels in patients in whom operative treatment is indicated at no more than two levels, from L1 to L5.
For this intended use, Moderate Degenerative Lumbar Spinal Stenosis was defined as follows:
- 25% to 50% reduction in the central canal and/or nerve root canal (subarticular, neuroforaminal) compared to the adjacent levels on radiographic studies, with radiographic confirmation of any one of the following:
- Evidence of thecal sac and/or cauda equina compression
- Evidence of nerve root impingement (displacement or compression) by either osseous or non-osseous elements
- Evidence of hypertrophic facets with canal encroachment
- AND Associated with the following clinical signs:
- Presents with moderately impaired Physical Function (PF) defined as a score of ≥ 2.0 of the Zurich Claudication Questionnaire (ZCQ)
- Ability to sit for 50 minutes without pain and to walk 50 feet or more.
The Superion IDS 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:
- 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);
- fracture of the spinous process, pars interarticularis, or laminae (unilateral or bilateral);
- 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;
- active systemic infection, or infection localized to the site of implantation;
- prior fusion or decompression procedure at the index level;
- morbid obesity defined as a body mass index (BMI) greater than 40.
The Superion IDS is manufactured from titanium alloy, which is known to produce MRI artifacts. Patients should be warned to disclose the presence of the Superion IDS prior to an MRI exam. Failure to do so may affect the quality of diagnostic information obtained from the scans.
The Superion IDS must be placed in the concavity between the spinous processes. If correct placement of the implant cannot be achieved due to variant anatomy, the physician should consider aborting the procedure because incorrect placement may result in device dislodgement, particularly if the patient experiences a traumatic event postoperatively.
The Superion IDS should only be used by physicians who are experienced and have undergone training in the use of the device. Only physicians who are familiar with the implant components, instruments, procedure, clinical applications, biomechanics, adverse events, and risks associated with the Superion IDS should use this device. A lack of adequate experience and/or training may lead to a higher incidence of adverse events.
Data have demonstrated that spinous process fractures can occur with Superion® IDS implantation. Potential predictors for spinous process fractures include:
- thin, or “gracile” spinous processes
- “kissing” spinous processes
- shallow or more dorsal placement of the device
- Radiological evidence of stenosis must be correlated with the patient’s symptoms before the diagnosis can be confirmed.
- If the spinous processes at the affected levels are not distracted in flexion, the Superion IDS may not be indicated.
- The safety and effectiveness of the Superion IDS has not been studied in patients with the following conditions: axial back pain without leg, buttock, or groin pain; symptomatic lumbar spinal stenosis at more than two levels; prior lumbar spine surgery; significant peripheral neuropathy; acute denervation secondary to radiculopathy; Paget’s disease; vertebral metastases; morbid obesity; pregnancy; a fixed motor deficit; angina; active rheumatoid arthritis; peripheral vascular disease; advanced diabetes; or other systemic disease that may affect the patient’s ability to walk.
- Implantation of the Superion IDS should be performed only by qualified and experienced spinal physicians having specific training in the implantation of the device, because this is a technically demanding procedure presenting risk of serious injury to the patient.
- Clinicians should not implant the Superion IDS until receiving adequate training in surgical technique.
- Inadequate training may result in poor outcomes and/or increased rates of adverse events.
- Spinous process fractures have been reported with this device type.
- Avoiding strenuous activity in the immediate postoperative period may be advisable.
Potential Adverse Events:
The following potential adverse events may occur as a result of interspinous process decompression with the Superion IDS:
- Risks associated with any surgical procedure include: anesthetic medication reactions; blood loss, blood vessel damage, phlebitis or hematoma; blood transfusion which may cause circulatory collapse, blood incompatibility, kidney damage, hepatitis or infection with HIV; myocardial infarction or circulatory problems; deep vein thrombosis, pulmonary embolism or thrombus formation in other vessels; stroke; fever or infection; pneumonia; injury to muscle, soft tissue or nerves; wound swelling, drainage or delayed healing; discomfort and rehabilitation associated with recovery from surgery; inability to perform certain tasks, such as lifting or exercise; and death.
- Risks associated with lumbar spine surgery include: damage to nerve roots or the spinal cord causing partial or complete sensory or motor loss (paralysis); loss of bladder and/or bowel functions; dural leaks (tears in the tissue surrounding and protecting the spinal cord); instruments used during surgery may break or malfunction which may cause damage to the operative site or adjacent structures; fracture, damage or remodeling of adjacent anatomy, including bony structures or soft tissues during or after surgery; new or worsened back or leg pain; and surgery at the incorrect location or level.
- Risks associated with lumbar spine implants and associated instruments include: sensitivity or allergy to the implant material; failure of the device/procedure to improve symptoms and/or function; pain and discomfort associated with the operative site or presence of implants; implant malposition or incorrect orientation; spinous process fracture; production of wear debris which may damage surrounding soft tissues including muscle or nerve; formation of scar tissue at implant site; migration or dislodgement of the implant from the original position so that it becomes ineffective or causes damage to adjacent bone or soft tissues including nerves; loosening, fatigue, deformation, breakage or disassembly of the implant, which may require another operation to remove the implant and may require another method treatment.
- Risks specifically associated with the Superion IDS include deformation, breakage or disassembly of the implant, and spinous process fracture.
Certain anatomical characteristics have been associated with an increased risk of spinous process fractures, while others may increase the difficulty of cannula and Implant placement.
Thin, or “gracile” Spinous Processes
Where a spinous process is unusually thin, or measures less than 20mm in superior-inferior dimension, the likelihood of a post-operative spinous process fracture may be increased.
Where spinous processes are in very close approximation, or are in contact (i.e., “kissing”), increased difficulty may be experienced in placement of the cannula. Where spinous processes do not “open up” in flexion, the likelihood of a spinous process fracture may be increased.
Implant Placement Location
Where the Superion™ Implant is placed in a “shallow” or more dorsal position, the likelihood of a post-operative spinous process fracture may increase by a factor >4. To reduce the potential for post-operative fracture, be certain to locate the implant body against the spinolaminar junction and confirm implant position fluoroscopically.