A spiral implant as nucleus prosthesis in the lumbar spine

Korge, Andreas; Nydegger, Th.; Polard, J.-L.; Mayer, H. M.; Husson, J. L.

doi:10.1007/s00586-002-0444-4

Cited by 52 publications

(7 citation statements)

References 7 publications

(4 reference statements)

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“…In addition to the restoration in axial deformability, the segment height was also restored with the new knitted implant. Again, similar results have been reported for other nucleus implants, such as the spiral implant (Newcleus, Zimmer spine, Warsaw, Indiana) 4 , 13 and the PDN. 11 This parameter is clinically relevant because insufficient height restoration or height loss can lead to a narrowing of the neuroforamen and to nerve root compression.…”

Section: Discussionsupporting

confidence: 86%

Biomechanical Behavior of a New Nucleus Prosthesis Made of Knitted Titanium Filaments

Kettler

Kaps²,

Haegele

et al. 2007

Int J Spine Surg

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BackgroundOne of the greatest challenges in the development of a nucleus prosthesis is to minimize the risk of implant expulsion. At the same time, the physiological flexibility, compressive behavior, and height of the disc should be restored. In this biomechanical in vitro study we investigated the ability of a new nucleus prosthesis made of knitted titanium filaments to meet these challenges.MethodsFlexibility, axial deformation, and height of six bovine lumbar spine segments were measured in the intact condition, after implantation of the new prosthesis, and during and after complex cyclic loading (100,000 cycles). For this purpose, six new prostheses preformed according to the shape of the bovine nucleus pulposus were manufactured. Flexibility was tested in the three main planes under pure moment loads of 7.5 Nm. Axial deformation was measured under application of an axial force of 1000 N. Radiographs taken before and after cyclic testing were used to assess implant migration and expulsion.ResultsIn lateral bending, the intact range of motion (RoM) could almost be restored after implantation. However, in axial rotation, the RoM increased slightly with the implant. This was also the case in extension, with an increase from -2.9° to -6.4°, whereas in flexion, RoM decreased from 4.3° to 3.2°. In all loading planes, cyclic loading caused the RoM to increase asymptotically by 0.1° to 1.8°. The axial deformation of the specimens was nearly equivalent in all tested states, as was their height. Cyclic loading did not cause implant expulsion.ConclusionsIn this feasibility study, the new knitted nucleus prosthesis showed promising results in segmental flexibility, axial deformability, height, and implant expulsion. However, further study is needed for other factors, such as wear and fatigue behavior.

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Section: Discussionsupporting

confidence: 86%

Biomechanical Behavior of a New Nucleus Prosthesis Made of Knitted Titanium Filaments

Kettler

Kaps²,

Haegele

et al. 2007

Int J Spine Surg

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“…Polyurethane has been shown to be useful as a biomaterial in a variety of spinal devices including posterior dynamic stabilization systems, 4 facet replacement systems, 5 disc replacement devices, 6 and even nucleus replacement devices. 7 …”

Section: Introductionmentioning

confidence: 99%

Mechanical and Biomechanical Characterization of a Polyurethane Nucleus Replacement Device Injected and Cured In Situ Within a Balloon

Tsantrizos¹,

Ordway

Myint³

et al. 2008

Int J Spine Surg

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BackgroundThe DASCOR device has recently been introduced as an innovative nucleus replacement alternative for the treatment of low-back pain caused by degenerative intervertebral disc disease. The purpose of this study was to characterize, through a series of preclinical mechanical bench and biomechanical tests, the effectiveness of this device.MethodsA number of samples were created using similar preparation methods in order to characterize the nucleus replacement device in multiple mechanical bench tests, using ASTM-guided protocols, where appropriate. Mechanical bench testing included static testing to characterize the device's compressive, shear properties, and fatigue testing to determine the device's compressive fatigue strength, wear, and durability. Biomechanical testing, using human cadaveric lumbar spines, was also conducted to determine the ability of the device to restore multidirectional segmental flexibility and to determine its resulting endplate contact stress.ResultsThe static compressive and shear moduli of the nucleus replacement device were determined to be between 4.2–5.6 MPa and 1.4–1.9 MPa, respectively. Similarly, the ultimate compressive and shear strength were 12,400 N and 6,993 N, respectively. The maximum axial compressive fatigue strength of the tested device that was able to withstand a runout without failure was determined to be approximately 3 MPa. The wear assessment determined that the device is durable and yielded minimal wear rates of 0.29mg/Mc. Finally, the biomechanical testing demonstrated that the device can restore the multidirectional segmental flexibility to a level seen in the intact condition while concurrently producing a uniform endplate contact stress.ConclusionsThe results of the present study provided a mechanical justification supporting the clinical use of the nucleus replacement device and also help explain and support the positive clinical results obtained from two European studies and one US pilot study.Clinical RelevanceNucleus replacement devices are rapidly emerging to address specific conditions of degenerative disc disease. Preclinical testing of such devices is paramount in order to potentially ensure successful clinical outcomes post implantation

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“…Nucleus replacement technology, available since the 90’ (PDN, Raymedica Inc., Minneapolis, USA), had good clinical results initially, followed by complications related to subsidence and extrusion. − As a result, many other implants have been created, ,,− only a few reaching the market, ,− and most are no longer in use. The reason is that although they achieve biomechanical restoration close to but not equal to an intact intervertebral disc, ,,,− extrusion and subsidence are not fully solved yet. ,,,, …”

Section: Discussionmentioning

confidence: 99%

Bionate Lumbar Disc Nucleus Prosthesis: Biomechanical Studies in Cadaveric Human Spines

Vanaclocha

Atienza

et al. 2022

ACS Omega

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Design: cadaveric spine nucleus replacement study. Objective: determining Bionate 80A nucleus replacement biomechanics in cadaveric spines. Methods: in cold preserved spines, with ligaments and discs intact, and no muscles, L3-L4, L4-L5, and L5-S1 nucleus implantation was done. Differences between customized and overdimensioned implants were compared. Flexion, extension, lateral bending, and torsion were measured in the intact spine, nucleotomy, and nucleus implantation specimens. Increasing load or bending moment was applied four times at 2, 4, 6, and 8 Nm, twice in increasing mode and twice in decreasing mode. Spine motion was recorded using stereophotogrammetry. Expulsion tests: cyclic compression of 50–550 N for 50,000 cycles, increasing the load until there was extreme flexion, implant extrusion, or anatomical structure collapse. Subsidence tests were done by increasing the compression to 6000 N load. Results: nucleotomy increased the disc mobility, which remained unchanged for the adjacent upper level but increased for the lower adjacent one, particularly in lateral bending and torsion. Nucleus implantation, compared to nucleotomy, reduced disc mobility except in flexion-extension and torsion, but intact mobility was no longer recovered, with no effect on upper or lower adjacent segments. The overdimensioned implant, compared to the customized implant, provided equal or sometimes higher mobility. Lamina, facet joint, and annulus removal during nucleotomy caused more damaged than that restored by nucleus implantation. No implant extrusion was observed under compression loads of 925–1068 N as anatomical structures collapsed before. No subsidence or vertebral body fractures were observed under compression loads of 6697.8–6812.3 N. Conclusions: nucleotomized disc and L1-S1 mobility increased moderately after cadaveric spine nucleus implantation compared to the intact status, partly due to operative anatomical damage. Our implant had shallow expulsion and subsidence risks.

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A spiral implant as nucleus prosthesis in the lumbar spine

Cited by 52 publications

References 7 publications

Biomechanical Behavior of a New Nucleus Prosthesis Made of Knitted Titanium Filaments

Biomechanical Behavior of a New Nucleus Prosthesis Made of Knitted Titanium Filaments

Mechanical and Biomechanical Characterization of a Polyurethane Nucleus Replacement Device Injected and Cured In Situ Within a Balloon

Bionate Lumbar Disc Nucleus Prosthesis: Biomechanical Studies in Cadaveric Human Spines

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