Canero G., MD, Rome (Italy) Rome American Hospital
S. Feliciano Clinic
www.islass.org
Epidemiology
Degenerative Lumbar Spinal Stenosis (DLSS)
Roughly 8% adult population affected by Degenerative Lumbar Spinal Stenosis (DLSS)
- Hillibrand AS, Rand N; Am Acad Orthop Surg – 1999 7(4)
20% of patients with low back pain (LBP) have a DLSS
- Zucherman et al;Spine – 2005; 30 - Boden et al;JBJS – 1990 72A(3) - Long DM et al; J Spine Disorders 1996 9(1)
DLSS Surgery in over 65 yrs old patients increased a lot over the past 20 years
- Katz JN; Spine 1995 20 (24suppl) - Ciol MA et al; J Am Geriatr Soc 1996 44(3) - Andersson Adult Spine GBJ; The 2° ed. 1997
Pathoanatomy
Degenerative changes:
Ligamentum flavum (hypertrophied enfolding posteriorly)
Pathoanatomy
Degenerative changes:
Facet joints (hypertrophied up to facet subluxation of a degenerative
spondylolisthesis)
Disc space (annular bulging contributing to narrowing of the canal)
Pathophysiology
Canal constriction meccanically affects the cauda nerve bundle and the free flow of cerebrospinal fluid around this bundle
In turn the nerve fiber is constricted and changes occur in the pia-arachnoid
By increasing the demand on the cauda (patient walking), because of mechanical constriction and associated ischemia, nutritional needs of the nerve roots cannot be satisfied
( Watanabe and Parke, J. Neurosurg, 1986)
Clinical findings
Clinical evidence of chronic nerve root irritation and compression with: narrowing of the spinal canal or neural foramina (Imaging +++) without vascular impairment to the lower extremities
Insidious symptoms onset of leg and back pain and paresthesias with ambulation, increasing in extension and relieving in flexion
→ Neurogenic Intermittent Claudication (NIC)
(Verbiest H.; JBJS 1954 -36B(2))
NEUROGENIC INTERMITTENT
CLAUDICATION
Pre Post
Current Treatment Options
Conservative management Physical therapy and drugs
Bracing
Epidural Steroids
Decompression surgery Open tecnique
Mininvasive technique (interspinous device)
Decompression surgery is superior to conservative choice in terms of pain relief and patient satisfation but success rate of surgery vary widely
(23 - 100%) !!!!
Turner J et al.; Spine 1992 17:1-8
Interspinous categories
Standalone
Combined with decompression surgery
Combined with fusion
Interspinous Spacers
- Stand Alone Intespinous Decompression
In-Space Aperius
X-Stop (eXtension Stop)
Stand Alone Interspinous
Decompression Systems (IDS)
- Stand Alone Decompression Systems vs Decompression Surgery:
SF 36 Data for Stand Alone: Superior outcomes at 1 yr
Stromqvist et al.; Spine Journal 2004 vol. 4, issue 5, suppl 1, : S58-59
SF 36 profiles before and 1 yr after spinal stenosis surgery: a prospective comparison of two techniques in
two nations
- Stand Alone Decompression Systems vs conservative:
Better symptoms severity score and patient satisfaction at 2yr (ZCQ)
Zucherman et al.; Spine 2005 30:1351-1358
Stand Alone Interspinous
Decompression
What is Stand Alone?
- Only purpose of surgery is to implant the device
- Pain relief and patient satisfaction based only on the
device implanted
Stand Alone Interspinous
Decompression What indications are best for stand alone?
- Foraminal Stenosis
- DLSS with neurogenic intermittent claudication
- Discogenic pain, black discs
- No indication to a fusion surgery
- Failed conservative treatment ( > 6 months)
Standalone
Mini open
Percutaneous
X-Stop eXtension Stop
Mini Open
Surgical Technique
Mini Open
X-Ray
•Canal area: 18%
•Canal diameter: 9%
•Subarticular diameter: 50%
Post op. Pre op.
Biomechanics
• Foramen area: 25%
• Foramen width: 41%
Biomechanics
Post op. Pre op.
Biomecanical transfer of loads
No overincrease pressure adjacent
Discs
Percutaneous stand alone
sistems
INSPACE
APERIUS
- Percutaneous
- Stand Alone Decompression
System
- Unilateral approach
- Respect thoracolumbar
fascia and sovraspinous
ligament
Aperius™ PercLID
Surgical technique
Percutaneous Trocar Insertion
under C-arm A-P / L-L view
TC post op
The System
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In-Space
Percutaneous
Interspinous Distraction
The implant
Components
1 Core
2 Screw
3 Wires
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2
3
1
In-situ deployment of the
anchorage
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When turning the screw
In-Space closes
and the wings are deployed along the spinous processes
In-situ deployment of the
anchorage
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Technical information
Component Material
1 Core PEEK
2 Wings TAV (Titanium Alloy)
3 Screw TAV
(Titanium Alloy)
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3
1
2
Technical information PEEK for undisturbed visualisation
TAV to control the correct positioning
of the implant
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Inspace vs aperius
inspace aperius
Peek
Percutaneous and
miniopen
Possibility to close wings
to remove device
No monouse
instrumentation
access: lateral
Titanium
Percutaneous
No possibility to close
wings to remove device
Monouse instrumentation
Access: posterolateral
Advantages
Postop standing after few hous
Fast functional recovery (no bracing)
Fast return to daily activities
Postop rehabilitation not necessary
Good patient’s satisfaction, compliance
and results if right indications →
Mild to Moderate DLSS
ADVANTAGES: Local Anesthesia
Avoid risks due to general anesthesiological procedures
Pecutaneous Technique
Reduction of operating time (10+/-5 min)
Reduction of risks and complications due to open surgery
(Bigger skin incision, bleeding, bone removal, muscle
damage, Postsurgical scar…)
No sovraspinous ligament removal (in comparison to other
Interspinous Spacers)
Can be used even in spine deformities (scoliosis <25
Cobb angle)
PITFALLS
Device mobilization
Spinosus process fracture
Dural sac tear (avoid in L5-S1)
Very Severe Stenosis (bone spur)
Tethered Cord
Insufficent Decompression
Interspinous Spacers
- Combined with decompression surgery
Coflex (
Indications
STENOSIS
DISCAL HERNIA
LORDOSIS DISORDER
Disc Herniation
Most often encountered at L4-L5
Imaging findings: facets hypertrophy,
slackness of the posterior supra-spinous ligament,
abnormal approximation of the spinous process (kissing spine)
Surgical treatment: Interspinous spacer
with/out Discectomy
Disc herniation
Stenosis
Central, lateral or foraminal stenosis
Surgical treatment : Interspinous spacer with
partial laminectomy, facetectomy and/or
foraminotomy
Stenosis
Stenosis + Static disorder
Ms MOT, 33 years Post-op
Segmental instability
Adjacent to fused level
• Accelerated degeneration of the adjacent segments
• Surgical treatment: topping off above or below the fused segment, to support newly created loads
Interspinous spacer combined with
decompression : advantages Simple and Safe
Good acceptability for surgeons and patients
Dynamic shock absorber allowing optimal mechanical
behavior in compression and flexion
Restorative restores the normal balance to the spine providing
stability and absorbing loads
Mini-invasive
StenoFix
The interspinous
spacer for
after surgical
decompression
The implants
5 sizes, from 8 to 16 mm
Sterile packed
Color coded with the trial
instruments
47
8 10 12 14 16
Anatomical fit
Features Benefits
Cranial radius Fits into the natural concavity of the superior spinous process
Caudal, long, flat surface Enhances the surface of contact with the inferior spinous
process
48
Comparative with Coflex
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StenoFix Coflex
1. Anatomical fit
StenoFix has through the good anatomical
fit a better surface of contact with the bone
Coflex has in a lot of patients a reduced
point of contact to the cranial spinous
process
StenoFix Coflex
2. Ventral positioning
Stenofix can be pushed more ventrally between
the 2 facets
= better ventral position
Coflex will hit the bony junction
between the laminae and the
spinous processes earlier.
50
10m
m
12
mm
Double implant StenoFix Coflex
3. Two levels implantation
Less wings impingement
The 2 implants can be placed in a good
ventral position.
Wings are not angulated and not staggered
enough.
The second implant cannot reach the same
ventral position as the first inserted implant
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StenoFix Coflex
4. Ease of use
The larger base of the Stenofix wings allows
an easier insertion between the cranial
spinous process
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Coflex StenoFix
9mm
7.5mm
StenoFix Coflex
5. Dampening characteristics
Spring designed for a uniform dampening
behavior, independently of where the loads
are transmitted to the implant.
The resulting stiffness of the implant is not
influenced by the implant positioning into
the patient
.
Depending of the anatomical sit of the
Coflex, the body load is transmitted to the
implant at different places from one patient
to the other.
Load transmitted posteriorly implant has
a low stiffness
Load transmitted more ventrally implant
is completely rigid
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High stiffness Low stiffness Uniform stiffness
X-ray Case Example
Interspinous combined with fusion
primaLock
romeo2pad
axle
aspen
Main features
These devices are ancorate to spinous
processes
All devices have the possibility to fill the
interspinous space with bone to obtain
artrodesis
Surgical technique Romeo pad
Perform a midline approach, resecting the supra-spinous and
interspinous ligaments. Use the process preparer and the
curette to clean the contact surface between implant and bone
on both sides of the spinous processes and between the
spinous processes.
The contact surface between the bone and the implant must
be free of tissue, muscles and ligaments.!
Insert the trial implant in order to determine the
correct size of the device.
Connect the plate with the PEEK cage
without clipping it yet, in order to ensure
maximum space between the plates to
facilitate the insertion of the implant
between the spinous processes.
Connect the implant to the implant holder by
screwing the threaded shaft into the PEEK
cylinder
Use the compression forceps to squeeze the
implant and
fix it on the spinous processes.
The implant has two hollows on each side that
receive
the tips of the tightener to secure the
connection. !
.
Final construct
These devices deliver simplified posterior stabilization and
renewed anatomical alignment for the following seven different
constructs.
Posterior Interlaminar Fusion with the Device
Posterolateral Fusion with the Device
ALIF with the Device
TLIF with Unilateral Pedicle Screws and the Device
TLIF with the Device
Hybrid Constructs/Revision Procedures
Direct Lateral with the Device
Benefits
Minimally invasive fusion device
Provides efficient and optimal placement for secure fixation
Innovative design accommodates wide range of anatomical variation
Integrated bone graft enclosure
Past: Anatomy’s Lesson of Doctor Tulip (Rembrandt, 1632)
Future Focusing: Less is More