537 - Elaspine™ Implant System, a Novel Lumbar Elastic Stabilization System....

#537 Elaspine™ Implant System, a Novel Lumbar Elastic Stabilization System. Preliminary Clinical Results after 12 Months Follow up

Posterior Dynamic Pedicular Stabilization

Poster Presented by: O. Kopetsch

Author(s):

O. Kopetsch (1)
R. Schoenmayr (1)
H. Anhalt (2)
R. Rissel (3)
M. Pfeiffer (4)
H. Schuster-Hulley (5)
A. Krepsz (3)
F. Kilian (5)

(1) Dr. Horst-Schmidt-Clinics, Department of Neurosurgery, Wiesbaden, Germany
(2) Medical Mind RCS, Clinical Research, Berlin, Germany
(3) Staufferklinikum Schwaebisch Gmuend, Spine Center, Mutlangen, Germany
(4) Loerrach Hospital Group, Spine Center, Loerrach, Germany
(5) Catholic Hospital Koblenz, Bruederhaus, Spine Center, Koblenz, Germany

Abstract

Introduction: The study device is a novel pedicle screw-based posterior elastic stabilization system for the lumbar spine. The key element is a polymer (PCU) rod with a form fit connection in the mono-axial pedicle screw head. The system is characterized by a linear, tissue-like force intake and load sharing properties resulting in a soft stop and a viscoelastic dampening attribute. Therefore there is no hard stop or posterior tension-band effect limiting flexion as with conventional dynamic stabilization systems. This way the device is capable of controlling the mobility in the sagittal plane and decreases the load on the disc and facet joints.

Materials and Methods: The main objectives of the ongoing prospective multicenter trial are device safety and efficacy. Clinical, procedural and radiological data as well as SF12, ODI and VAS are recorded at 3, 6, 12, 24, 60 and 120 months and compared with the baseline results. A two-sided t-test/two-sided signed rank test was performed to evaluate significant differences between pre-operative and post-operative data, where applicable.

Results: To date 45 patients are included in the present study. One device was explanted due to small pedicles (dysplasia) with spinal nerve compression, one patient was lost to follow up and two patients withdrew consent. One study device had to be explanted because of screw loosening, another because the patient needed additional spondylodesis in a neighboring section with a rigid fixation system. No further revision surgeries or device related adverse events were observed. Consequentially for this publication the data of 39 patients (62% female, 48 ± 8y, BMI 27.2 ± 4.8) were evaluated, whereof 24 patients have finished the 12 MFU.

The mean preoperative duration of chronic lower back pain was 5.7y ± 7.4, due to degenerative disc disease (97%), a dehydrated disc (87%), reduced disc height (76%) often combined with arthrotic or deformed facet joints (51%) and/or spinal stenosis (36%). The study patients were treated in 1 or 2 levels, mostly in L4/L5 (76%). The implantation was judged as “easy” or “acceptable to do” in 95% and only minor technical problems occurred. Mean pain and function scores as well as neurological data improved significantly from pre-operative to 12 MFU. VAS decreased by 30.2 ± 21.1 to 16.6 ± 18.3 (N=23; t=6.9, p< 0.0001) and Oswestry Disability Index by 30.9 ± 19.2 to 19.1 ± 17.9 (N=24, t=7.9, p< 0.0001). SF12V2 Simple Sum Score increased by 4.3 ± 5.7 to 25.8 ± 4.9 (N=24, t=3.7, p< 0.0013). A significant improvement became also visible at 12 MFU for the Straight Leg Raising Test (p=0.0010) and for deep tendon reflexes (p=0.0039).

Conclusion: These preliminary 12 months interim results demonstrated constant lumbar pain reduction over the complete follow up period, without any device related SAEs. This indicates that the study device was capable of reducing pain without safety concerns in this relatively short evaluation period.