G.Bonaldi Neuroradiologia, Ospedali Riuniti Bergamo - Italy A. Cianfoni Radiology Dept., Medical
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Transcript of G.Bonaldi Neuroradiologia, Ospedali Riuniti Bergamo - Italy A. Cianfoni Radiology Dept., Medical
G.BonaldiNeuroradiologia, Ospedali Riuniti
Bergamo - ItalyA. Cianfoni
Radiology Dept., MedicalUniversity South Carolina; Charleston,
SC, USA
Posterior Vertebral Arch Cement Augmentation to
Prevent Fracture of Spinous Processes after Interspinous
Spacer Implant
Intermittent neurogenic claudication
from spinal/foraminal
stenosis: pain/discomfort radiating to
buttocks/thigh/lower limbs, standing and
walking, exacerbated by lumbar extension, relieved by flexion
FACETS DEGENERATION PSEUDO-SPONDILOLISTHESIS
80
FACETS DEGENERATION FORAMINAL STENOSIS
Schematic of the X STOP in situ. The implant is placed between the
spinous processes. The lateral wings prevent anterior and lateral
migration, and the supraspinous ligament prevents posterior
migration.
The Treatment Mechanism of an Interspinous Process Implant for Lumbar Neurogenic Intermittent Claudication
Joshua C. Richards, et al. SPINE 2005;30:744–749
In extension, the implant significantly increased the canal area by 18% (231–273 mm2), the subarticular diameter
by 50% (2.5–3.7 mm), the canal diameter by 10% (17.8 –19.5 mm), the foraminal area by 25% (106–133 mm2), and the foraminal width by 41% (3.4 –
4.8 mm).
Conclusions: The results of this study show that the X STOP interspinous
process implant prevents narrowing of the spinal canal and foramina in
extension.
A randomized, controlled, prospective
multicenter trial comparing ...X STOP...with
patients treated nonoperatively.
191 patients were treated, 100 in the X STOP
group and 91 in the control group. A Multicenter, Prospective, Randomized Trial Evaluating the X STOP Interspinous Process
Decompression System for the Treatment of Neurogenic Intermittent ClaudicationTwo-Year Follow-Up Results
James F. Zucherman, et al. SPINE Volume 30, Number 12, pp 1351–1358, 2005
RESULTS
The X-STOP provides a conservative yet effective treatment for patients suffering from lumbar spinal stenosis.
A Multicenter, Prospective, Randomized Trial Evaluating the X STOP Interspinous ProcessDecompression System for the Treatment of Neurogenic Intermittent Claudication
Two-Year Follow-Up ResultsJames F. Zucherman, et al. SPINE Volume 30, Number 12, pp 1351–1358, 2005
...the success rate in the X-STOP interspinous process
decompression group was 78% at an average of 4.2 years postoperatively and are
consistent with 2-year results reported by Zucherman...
Interspinous process decompression with the X-STOP device for lumbar spinal stenosis: a 4-year follow-up study.
Kondrashov DG, Hannibal M, Hsu KY, Zucherman JF.J Spinal Disord Tech. 2006 Jul;19(5):323-7.
-z2
--z3
Bending moment
Bending moment
Extension with a rigid interspinous spacer
spacer
ICR
The rigid interspinous spacer will move the ICR posteriorly, modifying the loads on the different parts of
the S.U.
tension
compression
spaceruninstrumented
S.U. in extension
Back pain induced from pressure
originating in the facets and/or
posterior anulus of the lumbar spine may
be relieved by interspinous
decompression.The Effect of an Interspinous Process Implant on Facet
Loading During ExtensionCraig M. Wiseman, et al. SPINE 2005;30:903–907
InSpace
Superion(VertiFlex Incorporated)
APERIUS™ PercLID™ Systemby Kyphon (Medtronic)
Technique
Implant of rigid interspinous devices is contraindicated in osteoporotic patients.
But also elderly and/or osteopenic patients can be considered at risk for bone fragility and consequent fracture of spinous processes after device implant?
After 6 weeks
Polymethyl-Methacrylate (PMMA) bone cement augmentation of the posterior vertebral elements has been proven to increase stiffnessand failure load values of the augmented bony structures in a cadaveric study
A novel technique of intra-spinous process injection of PMMA to
augment the strength of an inter-spinous process devicesuch as the X STOP.
Idler C, Zucherman, JF, Yerby S, Hsu KY, Hannibal M, Kondrashov D. Spine. 2008;33:452-456.
Von Mises stresses of the structure
Table
Case 1Osteoporosis in Spinal
Process-
Osteoporosis in Lamina
Case 2Bone Cement in Spinal
Process-
Osteoporosis in Lamina
Case 3Bone Cement in Spinal
Process-
Bone Cement in Lamina
0.534E-7 0.513E-7 0.456E-7Strain
Stress [MPa] 41.679 39.877 37.679
Study Design: Non-randomized, historically controlled, clinical trial
To assess the safety, feasibility, and effectiveness of posterior vertebral arch cement augmentation in preventing delayed spinous processes’ fracture after interspinous spacer device implant in patients with risk factors for fragility fractures.
Patients were classified at risk of fragility fractures according to one of the following criteria:
•age >75 years•osteopenia (as defined by WHO on a bone scan with a T-score < -1.0)•history of prior fragility fracture•chronic steroid therapy.
Laminoplastyoperative technique
From June 2007 to March 2010, we implanted interspinous spacers in 35 eligible patients with risk factors for fragility fractures
16 patients did not undergo laminoplasty
19 patients laminoplasty was also performed
The combined procedure was uneventful in all 19 patients, except for minor paralaminar leakages, asymptomatic. No intraforaminal or intravascular leakages.
A symptomatic delayed spinous process fracture was diagnosed in 4 out of 16 patients who did not undergo laminoplasty (25.0%), while no fractures were diagnosed in the 19 treated patients (p=0.035).
CONCLUSIONLaminoplasty is feasible
and safe.It seems effective inpreventing delayed
fractures of the posterior arch after interspinous spacer placement, in
patientsat risk for fragility
fractures.