Transcript X STOPPK™ Interspinous Process Decompression (IPD®) System

X STOP™
Interspinous Process
Decompression (IPD®) System
Marco Artiano, M.A.
Chapman University
Doctor of Physical Therapy Program
July 2008
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FDA Approval?
• FDA Approved 11/21/05
• St. Francis Medical Technologies, Inc.
Address: 960 Atlantic Avenue, Suite 102
Alameda, CA 94501
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http://www.fda.gov/cdrh/pdf4/p040001a.pdf
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What is X STOP?
• The X STOP ® Interspinous Process Decompression System
(aka “X STOP”) is used to relieve symptoms of lumbar spinal
stenosis. The X STOP® is a titanium implant that fits
between the spinous processes of the (lumbar) spine. It is
made from titanium alloy and consists of two components:
a spacer assembly and a wing assembly.
• How does it work? The X STOP® implant is placed between
the spinous processes of the symptomatic lumbar levels.
The X STOP® is designed to limit extension of the spine in
the affected area, which may relieve the symptoms of
lumbar spinal stenosis.
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X STOP™ - Indications for use
• The X STOP® implant is indicated for treatment of patients
aged 50 or older suffering from pain or neurogenic
intermittent claudication in the legs secondary to a
confirmed diagnosis of lumbar spinal stenosis. 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.
• What will it accomplish? The X STOP® may relieve some or
all of the symptoms of lumbar spinal stenosis and may
improve a patient’s ability to function.
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X STOP™ - Indications for use
• Neurogenic Intermittent
Claudication (NIC: leg,
buttock, or groin pain that is
relieved when the spine is
flexed such as when sitting in a
chair), due to Central and/or
Lateral-Recess Lumbar Spinal
Stenosis.
• Spondylolisthesis up to
grade 1.5 /4 (~35%), with NIC.
• Baastrup’s Syndrome /
‘Kissing Spine’.
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• Axial-load induced back
pain.
• Facet Syndrome.
• Degenerative and/or
Iatrogenic (postdiscectomy) Disc
Syndrome.
• Contained HNP.
• Unloading of disc adjacent
to a Lumbar Fusion
Procedure, primary or
secondary.
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X STOP® Contraindications
The X STOP® should not be used
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 the body:
• Neural compression causing
neurogenic bowel or bladder
dysfunction;
• Diagnosis of severe
osteoporosis
• Active systemic infection or
infection localized to the site
of implantation.
– significant instability of the
lumbar spine
– an ankylosed segment at the
affected level(s)
– acute fracture of the spinous
process or pars interarticularis
– significant scoliosis
http://www.fda.gov/cdrh/pdf4/p040001.html
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X STOP™- Surgical Technique
• Safe and accurate / No
risk to neural elements
• Can be performed
under local anesthesia
• Performed as same-day
or short-stay routine
http://www.kyphon.com/sfmt/press/xstop.html
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X STOP™- Surgical Technique
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http://www.sfmt.com/sfmteuro/indications.html
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X STOP ™ - Unloads
It unloads:
• Posterior annulus
pressure by avg. of 63%
• Posterior nucleus
pulposus pressure by
avg. of 41%
• Facet force by avg. of
68%
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http://www.sfmt.com/sfmteuro/indications.html
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X STOP ™ Benefits
• Anatomical structures:
– Supraspinous ligaments
– Interspinous ligaments
– No bone-removal:
• Direct decompression is
not required
• Modification of the
spinous processes and/or
lamina is not required
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• Kinematics:
– Extension is limited,
flexion remains
unchanged
– Lateral bending and axial
rotation remain
unchanged
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X STOP ™ Benefits
• Sagittal Alignment:
– Increases disc height
– Restores sagittal balance
• Forward bending by
patient no longer
necessary
• Patients resume normal
posture
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• Preserves Treatment
options:
– All alternative surgical
options are still open; all
of the original anatomy
is intact
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X STOP™ Decompresses
• The dimensions of the
spinal canal and lateral
neural foramen change
significantly with posture.
• In a degenerated spinal
segment, extension can
cause anatomic structures
to compress the spinal cord
and/or nerves, leading to
various symptoms including
neurogenic intermittent
claudication (NIC).
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X STOP™ Decompresses
• The XSTOPPK™
significantly prevents
narrowing of the spinal
canal and neural
foramina in extension,
decompressing the
individual degenerative
spinal level(s) that
provokes symptoms.
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X STOP™ Functional Benefits
• X STOPPK is designed to
relieve the patient’s
symptoms while
standing and walking,
which allows the
patient to resume their
normal posture.
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X STOP™ - Postoperative Care
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Ambulation begins immediately after
recovery and the patient is usually
discharged one to two hours after the
procedure.
Shower and drive a car the following day.
Apply an ice pack. Non steroidal antiinflammatory drugs (ANSAIDs) are
prescribed and mild analgesics and muscle
relaxants as needed.
Return to usual activities in 10 -14 days.
No heavy labor or prolonged sitting.
Mild progressive exercise program can
begin the day after the surgery.
Walking- as tolerated but not to exceed
one hour in duration.
After two weeks, cycling as tolerated.
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Physical Therapy is recommended for the
first several weeks following surgery to
condition the patient and to allow the
patient's spine to adjust to the implant.
Gradual physical activity, with progression
is recommended for the first 6 weeks.
Avoid hyperextension of the spine
No heavy lifting, no stair climbing, no
sports such as swimming, golfing, tennis,
racquetball, running or jogging. This will
avoid damage to the spinal processes.
Strenuous activities and swimming may be
added at six months.
A stress fracture of the spinal process may
occur if strenuous physical activity is
resumed too soon postoperatively.
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Studies: The X STOP May Reduce Neurogenic Claudication in
Lumbar Spinal Stenosis
Spine. 2005;30:1351-1358
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Patients were at least 50 years old and had leg, buttock, or
groin pain. All were able to walk at least 50 feet. Patients
with a fixed motor deficit, cauda equina syndrome, previous
lumbar surgery, or spondylolisthesis of more than grade 1
were excluded from the research protocol.
Patients were randomized to receive either conservative
therapy or X STOP. Those in the conservative therapy group
all received at least 1 steroid injection along with analgesics
and physical therapy as necessary.
Study participants were examined at 6 weeks, 6 months, 1
year, and 2 years for the main study outcomes. Outcomes
were drawn from the Zurich Claudication Questionnaire and
included measurements of symptoms and physical function.
Patient satisfaction and radiographic changes were also
assessed.
191 patients were randomized from 9 U.S. centers. The
mean age was 69 years, and baseline symptoms and
physical function were similar between the 2 treatment
groups. Spondylolisthesis of grade 1 or less was present in
approximately one third of the cohort.
In the X STOP group, 100 patients received implants at 136
levels. The average procedure time was 54 minutes, and 97
of the procedures were completed under local anesthesia.
The control group received a total of 216 epidural steroid
injections during the study period.
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The X STOP group performed significantly better in the main
study outcomes. This improvement was evident at 6 weeks and
remained static during the rest of the trial period. At 2 years, the
mean improvement in symptom severity was 45.4% in the X STOP
group, compared with 7.4% in the conservative management
group. Improvements in physical function were 44.3% and -0.4%,
respectively.
Rates of clinically significant improvement in symptoms and
physical function in the X STOP cohort were 60.2% and 57%,
respectively. The respective values for the conservative
management group were 18.5% and 14.8%.
73.1% of participants in the X STOP group reported being at least
somewhat satisfied with treatment, compared with 35.9% of the
conservative therapy group. This difference was also significant.
Factors associated with a better outcome with X STOP were the
absence of comorbid conditions and lower surgical blood loss. In
contrast, a positive femoral stretch test was associated with
worse outcomes in the X STOP cohort.
Rates of decompressive surgery were 26.4% in the conservative
therapy group and 6% in the X STOP group.
Radiographic measurements were similar between groups at 12
and 24 months.
No device-related intraoperative complications were reported
with X STOP. There were 3 reports of complications associated
with X STOP surgery, and 3 participants reported device-related
complications during the follow-up period. In comparison, there
were 5 complications associated with epidural injection.
http://www.medscape.com/viewarticle/507174_print
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Studies: High failure rate of the interspinous distraction device
(X-Stop) for the treatment of lumbar spinal stenosis caused by
degenerative spondylolisthesis.
Verhoof, OJ, Bron , LJ, Wapstra, FH, van Royen BJ.Eur Spine J (2008) 17:188–192
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A cohort of 12 consecutive patients with symptomatic lumbar spinal stenosis
caused by degenerative spondylolisthesis were treated with the X-Stop.
All patients had low back pain, neurogenic claudication and radiculopathy. MRI of
the lumbosacral spine showed a severe stenosis.
10 patients the X-Stop was placed at the L4–5 level. 2 patients were treated at
both, L3–4 and L4–5 level.
The mean follow-up was 30.3 months.
Recurrence of pain, neurogenic claudication, and worsening of neurological
symptoms was observed in three patients within 24 months. Post-operative
radiographs and MRI did not show any changes in the percentage of slip or spinal
dimensions.
Finally, secondary surgical treatment by decompression with posterolateral fusion
was performed in seven patients (58%) within 24 months.
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Spinal Pathology
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X STOP™ - The Surgery
by John C. Chiu, M.D., D.Sc, F.R.C.S
Department of Neurospine Surgery
California Center for Minimally Invasive Spine Surgery
California Spine Institute Medical Center
John C. Chiu: Treatment Of Lumbar Spinal Stenosis With Interspinous Process Decompression System (IPD) (X-Stop®):
The Internet Journal of Minimally Invasive Spinal Technology. 2007; Volume 1, Number 1.
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X STOP™ - The Surgery
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Anesthesia
The surgeon may typically use monitored IV
conscious mild sedation combined with local
anesthesia, allowing a greater selection of
higher anesthesia risk patients for this IPD
procedure. In this manner, the anesthesiologist
or the anesthetist can administer 2 g of Ancef
and 8 mg dexamethasone IV at the start of the
procedure. Local anesthesia of 1% Xylocaine
mixed with 0.25% Marcaine is injected into
subcutaneous tissue and paraspinal tissue. The
patient should be sedated but remain awake
and responsive to verbal commands (conscious
sedation). Patients should not be disoriented.
The use of surface EEG monitoring provides
added precision of anesthesia delivery, and
offers an additional safeguard for patients
undergoing this IPD procedure.
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X STOP™ - The Surgery
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Skin incision and localization
After the surgical field is prepped and
draped, a 4-8 cm. vertical midline lumbar
incision is made over the proper spinal
processes, under fluoroscopic guidance.
Using an 18 gauge spinal needle, the
intraspinal process space for IPD insertion
can be identified fluoroscopically.
Of course, the skin and fascia are
infiltrated on both sides of the
supraspinous ligament, leaving 1.5 cm. of
ligament width intact . Also posterior rami
nerves along the posterior aspect of facets
joints and pars are infiltrated. A retractor
is placed in after subperiosteal dissection
of the tissue.
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X STOP™ - The Surgery
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Creating the pilot hole
After incision of the lumbar fascia on
either side of the spinal processes and
supraspinous ligament, the dissection of
the paraspinal muscle is performed,
separating the bony spinal processes and
lamina. The supraspinous ligament is
preserved. With flexion position of the
lumbar spine, the interspinous ligament is
entered with a small curved dilator by
paralleling the dilator to the spinous
process until the facet is encountered,
then rotating the instrument 90° and
interspinous ligament with the tip of
dilator into the lowest point of the
interspinous ligament . Fluoroscopy is
used to confirm the position of the dilator.
A larger sized dilator is to follow to dilate
the ligamentous opening further.
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X STOP™ - The Surgery
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Application of the sizing distractor.
The sizing distractor is to be placed in the
same opening as far anteriorly toward the
lumbar lamina as possible for advancing of
the distractor. A finger on the
contralateral margin of the interspinous
ligament to find the tip of the distractor as
it passes through the opening. Once the
distractor is in place, squeeze its handle
gently and slowly until the resistance is
encountered. As the handles are squeezed
more and more, resistance should
increase. When the supraspinous ligament
becomes taut, optimal sizing has been
achieved. Fluoroscopy is utilized for
confirmation.
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X STOP™ - The Surgery
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With the handles open, the tip of the
sizing distractor is shaping the opening of
the spacer of X-STOP® implant. The
measurement of the opening for the
distractor ranges from 6 mm. to 14 mm.
corresponding to the size of the X-STOP®
implants available. A locking nut at the
base of the handle can be adjusted to fix
the tips at specific size.
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X-STOP implants: 6mm – 14mm sizes
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X STOP™ - Implantation
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X STOP™ - Fluoroscopic Confirmation
Lateral and AP views of fluoroscopic confirmation of the X-STOP implant at L4 – L5 in proper position
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X STOP™ - Two Implants
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When two X-STOP® implants are
placed at adjacent levels, usually
there is a slight overlap of the
superior and inferior implant wing
with the shorter wing of the
superior implant positioned
posteriorly to the long tapered
wing of the inferior implant.
Rotation of the inferior implant
wing would be effectively
prevented. Again, fluoroscopy
confirms the correct placement of
the X-STOP's .
Fluoroscopic confirmation of the X-STOP implants at L3-L4 and L4 – L5 in proper position
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References
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Lindsey DP, Swanson KE, Fuchs P, et al. The Effects of an Interspinous Implant on the Kinematics of the
Instrumented and Adjacent Levels in the Lumbar Spine. Spine, 2003. 28(19): p. 2192-7.
Richards J, Majumdar S, Lindsey DP, et al. The Treatment Mechanism of an Interspinous Process Implant for
Lumbar Neurogenic Intermittent Claudication. Spine. 2005 Apr 1;30(7):744-9.
Swanson KE, Lindsey DP, Hsu KY, et al. The Effects of an Interspinous Implant on Intervertebral Disc Pressures.
Spine, 2003. 28(1): p. 26-32.
Wiseman C, Lindsey D, Fredrick A, et al. The Effect of an Interspinous Process Implant on Facet Loading During
Extension. Spine. 2005 Apr 15;30(8):903-7.
Zucherman JF, Hsu KY, Hartjen CA, et al. A Multicenter, Prospective, Randomized Trial Evaluating the X STOP
Interspinous Process Decompression System for the Treatment of Neurogenic Intermittent Claudication: Two-Year
Follow-Up Results. Spine. 2005 Jun 15;30(12):1351-1358.
Lindsey DP, Swanson KE, Fuchs P, et al. The Effects of an Interspinous Implant on the Kinematics of the
Instrumented and Adjacent Levels in the Lumbar Spine. Spine, 2003. 28(19): p. 2192-7.
Richards J, Majumdar S, Lindsey DP, et al. The Treatment Mechanism of an Interspinous Process Implant for
Lumbar Neurogenic Intermittent Claudication. Spine. 2005 Apr 1;30(7):744-9.
Swanson KE, Lindsey DP, Hsu KY, et al. The Effects of an Interspinous Implant on Intervertebral Disc Pressures.
Spine, 2003. 28(1): p. 26-32.
Wiseman C, Lindsey D, Fredrick A, et al. The Effect of an Interspinous Process Implant on Facet Loading During
Extension. Spine. 2005 Apr 15;30(8):903-7.
Zucherman JF, Hsu KY, Hartjen CA, et al. A Multicenter, Prospective, Randomized Trial Evaluating the X STOP
Interspinous Process Decompression System for the Treatment of Neurogenic Intermittent Claudication: Two-Year
Follow-Up Results. Spine. 2005 Jun 15;30(12):1351-1358.
Chiu J. Treatment Of Lumbar Spinal Stenosis With Interspinous Process Decompression System (IPD) (XStop®): The Internet Journal of Minimally Invasive Spinal Technology. 2007; Volume 1, Number 1.
http://www.youtube.com/watch?v=cMzp4dkcSEE – a movie of the X-Stop procedure
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