For some patients suffering from lumbar spinal stenosis (LSS), standing upright and walking just a few feet can be excruciating. In many of the worst cases, the only way to get any true relief is by sitting or leaning over. Unfortunately, adopting these sedentary poses can often lead to a host of other health problems as the patient's weight balloons.
A degenerative condition, LSS is the most common cause of back surgery in patients over age 50. The condition, which can be congenital or acquired, occurs as the lumbar spinal canal shrinks over time and narrows to a point where the nerves to the legs are compressed. Up until recently, the only two options have been temporary pain relief or open surgery.
"Previously the choices were nonoperative care, which ranged from modifying activities, taking aspirin and some physical therapy up through epidural injections … steroidal injections," explains Kevin Sidow, president and CEO of St. Francis Medical Technologies, Inc.
"On the other side of the spectrum is laminectomy, which is surgically removing the bone from the affected areas. We felt strongly that there was a large gap there, and the gap is now being filled by X STOP®."
X STOP Interspinous Process Decompression (IPD®) System, which received FDA approval in November 2005, was invented by Dr. James Zucherman and Dr. Ken Hsu — both orthopaedic spine surgeons who practice at St. Mary's Medical Center and St. Luke's Hospital in San Francisco.
Inserted through a small incision, the titanium alloy ring, or spacer, is not actually affixed to bone but rather sits between two spinous processes and is held in place by the implant's "wings" and by surrounding ligaments. Once inserted, the X STOP keeps the lower spinal canal open, thereby mimicking the relief patients receive through flexion but on a full-time basis so that symptoms abate even when standing upright.
"Many times when we have new technology using that new procedure will preclude doing the more traditional technique," says Dr. Nick Shamie, assistant professor of orthopaedics and neurosurgery at UCLA, who participated in the clinical trials. "With X STOP, you absolutely can remove the implant, reverse your steps and do the procedure you would have done before X STOP existed … you don't burn any bridges."
Sidow concurs, saying one of the chief benefits of this new "in between" medical intervention is that it does not compromise any therapeutic options downstream.
Shamie adds that about 97 percent of the patients who undergo the minimally invasive procedure are only given a local anesthetic. As a matter of fact, he says patients often play an active role in the surgery by recreating the position that provides maximum relief while on the operating table.
The entire process is relatively quick. "It takes about an hour in a double level," says Shamie. "In a single level, you could do it in close to a half-hour. We keep them (patients) overnight for observation, but we're moving more toward an outpatient procedure."
As for results, Shamie says they are immediate.
Outcomes have been equally impressive. In a head-to-head comparison of clinical success at the 24-month mark, 63.4 percent of patients in a randomized, controlled, multicenter trial that received X STOP were identified as having statistically significant improvement in pain relief and physical function as opposed to only 12.9 percent of those receiving nonoperative treatments. The two-year study was published this past June in the Journal of Neurosurgery: Spine.
Similar results were reported in the July issue of the Journal of Spinal Disorders & Techniques, which highlighted intermediate term efficacy at the four-year mark. The study followed a cohort of 23 patients who had received the X STOP. Using the Oswestry Disability Index (ODI), the mean preoperative score was a 45 (range was 20-80). Postoperatively, the mean ODI score dropped to 15, and the mean improvement score was 29 points. Using a 15-point improvement from baseline ODI as the criterion for defining a successful outcome, 14 out of 18 patients, or 78 percent, met with success.
Of course, Shamie points out, "With any procedure that we do, picking the right patient is key."
He adds that patients who do not get relief from a sitting or stooping position will not be good candidates for this procedure. Furthermore, he notes FDA approval is for patients 50 and older with a level one or two lumbar stenosis.
While Shamie says there are some anatomic anomalies among patients, X STOP typically will not work for lumbar stenosis if the degeneration reaches the L5-S1 level as the space is generally too small for the implant. In the right patients, however, the X STOP can be life changing.
"The worst result I've had personally is a patient that got 70 percent better," says Shamie, who has performed approximately 40 implants during clinical trials and post-FDA approval. He adds that his best result was a 72-year-old woman who had a contraindication for general anesthesia and therefore wasn't a candidate for traditional decompressive laminectomy. "Her LSS was so bad, she could only walk for a few feet before the searing pain made her want to sit down." After surgery, he continues, the patient was quickly up and around and so excited she was giving him hugs and kisses.
Shamie adds with a laugh, "Patients feel better immediately and want to go tell everyone … it's a great source of referral."
Sidow notes that while X STOP cannot reverse the degeneration that has already occurred, by allowing patients to once again become active and lose weight through movement, it can slow down the degenerative process and help stem the cascade of other diseases that are associated with a sedentary lifestyle.
For reimbursements on the hospital side, Sidow says CMS has granted X STOP an ICD-9 procedural code that maps to the DRG number 499/500.
"We've also been granted, effective Oct. 1, a CMS add-on payment of up to $4,400 for the X STOP procedure," he adds.
On the surgeon's side, Sidow says the recommendation has been to handle the new procedure by filing under an unlisted code. Insurers are reviewing on a case-by-case basis, but Sidow notes that preauthorization has been granted the vast majority of the time.
Since FDA approval, more than 1500 patients have undergone the new procedure.
"I think the results are dramatic," concludes Dr. Shamie.
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October 2006
