X-Stop is a spinal implant that is designed to treat lumbar central canal stenosis with a minimally invasive surgical procedure. This device was created to facilitate an alternative surgical intervention versus the more invasive laminectomy technique that is typically used to resolve lower back stenotic changes.
This small, two-part titanium spinal implant device is also known as the Interspinous Process Decompression System (IPDS) and is manufactured by Medtronic (NYSE MDT). The device was cleared by the FDA for use as a surgical lumbar spinal stenosis treatment in 2005.
IPDS allows patients to receive a moderate level of treatment for single and double adjacent level lumbar stenosis that has not responded to more conservative care practices. More importantly, it allows patients to potentially avoid more invasive laminectomy and possible spinal fusion, which is a far worse ordeal to suffer through.
This guide examines the use of the IPDS system and the X-Stop implant device. We will detail the indications and contraindications for treatment, the procedure utilized and provide an overview of the results in the first ten years of clinical application.
X-Stop is basically a metal bar that is placed, but not secured, in between the spinous processes at the stenosis level(s) of the lumbar region. The device mechanically prevents the vertebrae from coming closer together and minimizes certain movements of the spinal structures.
The implant is designed to prevent the spine from bending backwards, which will decrease the patency of the central vertebral canal. By maintaining a more patent spinal canal, the nerves will have more functional room and symptoms should resolve. The implant also prevents a moderate amount of side-to-side twisting movement in the treated areas of the spine.
IPDS is indicated for patients with strictly-controlled criteria relating to single and adjacent double level lumbar spinal stenosis only. Patients must demonstrate these additional attributes in order to qualify for IPDS care:
Qualified patients must be over 50 years old and not demonstrate any contraindicating factors that would preclude treatment. Some of these factors include lumbar vertebral listhesis, osteoporosis, history of lumbar fracture or prior surgery, evidence of certain spinal joint abnormalities, sensitivity to metal implants, abnormal lumbar spinal curvature or certain neurological expression, such as CES, that might be better treated using open spinal nerve decompression.
Patients must have undergone confirmation imaging indicating appropriate single or double level spinal stenosis in the lower back and must have tried a variety of conservative care methods which have not provided acceptable results for at least 6 months time.
Patients must report a history of buttocks, leg or foot symptoms of a radicular nature, often diagnosed as sciatica. The existence of actual back pain is not a qualifying or determining factor for treatment.
Patient should demonstrate marked pain relief when flexing the spine forward, as when bending at the waistline.
The IPSD procedure is rather simple and minimally invasive, especially when compared to the various manifestations of laminectomy that are often used to resolve similar stenosis issues in the lumbar spine. The technique can be performed under local or general anesthetic, depending on surgeon preference and particular patient criteria.
The operation utilizes a single small incision placed directly over the spine at the operated level(s). The surgeon will utilize live imaging equipment to visualize the stenotic levels and create space for the implant before it is inserted in between the affected spinous processes. The implant is not attached to the vertebrae, as it is held in place organically through design of the body interacting with the shape of the implant itself.
The entire operation generally takes between 30 to 60 minutes and most patients will be encouraged to stand and walk almost immediately after surgery. Some patients can leave the hospital the same day, but most will stay overnight for observation for a day or two before being released.
Patients will be advised to maintain limited physical exertion levels for 2 to 6 weeks on average. Prohibited activities include no backward bending or twisting of the spine, no strenuous exertion, no impact activities, no climbing stairs or using a stepper and no positioning that could put undue stress on the implant or the operated site.
Some patients will require physical therapy after the procedure, while most could benefit from it. A physical therapist trained in dealing with postoperative IPDS patients can be helpful in learning to live with the new implant and minimizing the risk of suffering activity-related complications.
IPDS demonstrates certain advantages over laminectomy, but is certainly far from a perfect treatment for lumbar spinal stenosis.
On the positive side, the Interspinous Process Decompression System is truly minimally invasive and does not disturb the spinal canal or the spinal nerves. This is a huge benefit compared to more invasive forms of spinal surgery typically used to resolve lumbar stenosis. This fact also greatly diminishes the incidence of spinal nerve damage and increased symptomology when compared to laminectomy and laminectomy combined with spondylodesis.
Interspinous Process Decompression System does not preclude the patient from undergoing more invasive versions of surgery, such as the above mentioned techniques, if the symptoms do not resolve with time.
When used for indicated patient conditions, the device demonstrates good results for relieving pain, with minimal risk of serious complications.
The possible downside of Interspinous Process Decompression System implant use includes many negative patient citations, including a moderate degree of continuing pain. Some patients are not helped at all using the IPDS implant, while others suffer a recurrence of pain, even when the implant is shown to be optimally placed and functioning perfectly. These instances might speak more to diagnostic error than device ineffectiveness. Remember, inaccurate diagnosis is a huge concern in the back and neck pain treatment sector.
There are some patients who report implant migration. The device can slip out of place, possibly causing serious pain and the potential for spinal joint injury. Spinous process fracture might cause this shift in position or can result from a spontaneous shift in implant position.
Some patients have reported implant failure due to design defects. The device consists of two parts and can fail given certain rare circumstances.
Some patients suffer implant rejection by their bodies or infections related to the implant device. While most infections can be cured, some are recurrent. Both scenarios of rejection and episodic infection usually entail implant removal.
We like to see progress being made towards providing potentially curative stenosis care without drastic and dangerous surgery. Sure, the Interspinous Process Decompression System procedure is not without risk, but it is usually far better tolerated, mind and body, than the alternative traditional surgical methods.
All treatments are designed to work for highly specific conditions and IPDS is no exception to this rule. We see evidence that in most cases of failed results that do not involve obvious device defect or slippage, the diagnosis is the most likely culprit for the unsatisfying outcome of therapy.
It is vital to remember that lumbar stenosis is universal as we get older and is often coincidental to pain suffered. Treatment results from all manner of stenosis therapies support this statement 100%.
If the X-Stop fails to deliver, it might be advised to reconsider the diagnosis naming the actual symptomatic source, as this might just be the weak link in the treatment chain.