G.Bonaldi Neuroradiologia, Ospedali Riuniti Bergamo - Italy A. Cianfoni Radiology Dept., Medical University 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

8 0 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 Claudication Two-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 Process Decompression System for the Treatment of Neurogenic Intermittent Claudication Two-Year Follow-Up Results James 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 Jul;19(5):323-7.

-  z2 -  -  z3 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 Extension Craig M. Wiseman, et al. SPINE 2005;30:903–907

InSpace

Superion (VertiFlex Incorporated)

APERIUS™ PercLID™ System by 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 stiffness and 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 device such as the X STOP. Idler C, Zucherman, JF, Yerby S, Hsu KY, Hannibal M, Kondrashov D. Spine. 2008;33:

Von Mises stresses of the structure

Table

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.

Laminoplasty operative 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).

CONCLUSION Laminoplasty is feasible and safe. It seems effective in preventing delayed fractures of the posterior arch after interspinous spacer placement, in patients at risk for fragility fractures.

Thank you GRAZIE