Implant Failure of Titanium Versus Cobalt-Chromium Growing Rods in Early-onset Scoliosis

Shinohara, Kensuke; Takigawa, Tomoyuki; Tanaka, Masato; Sugimoto, Yukihiko; Arataki, Shinya; Yamane, Kyoko; Watanabe, Noriyuki; Ozaki, Toshifumi; Sarai, Takaaki

doi:10.1097/brs.0000000000001267

Cited by 23 publications

(21 citation statements)

References 12 publications

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“…Failure was not associated with the degree of curve, length of time, or age of the child. The overall mechanical failure rate (all causes) in our cohort was 50%, which agrees with the failure rate of TGR systems that has been previously reported (approximately 40%–70%) [ 3 , 14 - 17 ]. The patient’s size, contouring of rods, actuator magnets that are too close to one another, and actuator magnets too close to the apex of the curve are factors associated with the failure of magnetically controlled lengthening devices [ 18 ].…”

Section: Discussionsupporting

confidence: 91%

“…We distinguish failure in which a further MCGR system is inserted from failure that is treated by final spinal fusion. The exact conditions for failure may become more obvious over time, and there certainly appears to be some correlation in the literature with increasing body habitus, age of the child, and orientation of magnets [ 14 , 18 ]. However, we are hesitant to label cases as failures if the children subsequently went on to be treated with final spinal fusion, which would be appropriate for the child in any event.…”

Section: Discussionmentioning

confidence: 99%

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Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years

et al. 2018

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Study DesignRetrospective observational study of a continuous series of 28 children.PurposeTo determine the mechanical failure rate in our cohort of children treated with magnetically controlled growth rods (MCGRs).Overview of LiteraturePrevious studies report a MCGR mechanical failure rate of 0%–75%.MethodsAll patients with MCGR implantation between 2012 and 2015 were examined and followed up for a minimum of 2 years. A retrospective evaluation of contemporaneously documented clinical findings was conducted, and radiographs were retrospectively examined for mechanical failure. The external remote controller (ERC)-specified length achieved in the clinic was compared to the length measured on subsequent radiographs.ResultsFourteen mechanical failures were identified in 28 children (50%) across a total of 52 rods (24 pairs and four single constructs). Mechanical failures were due to: failure to lengthen under general anesthesia (seven children), actuator pin fracture (four), rod fracture (one), foundation screw failure (one), and ran out of rod length (one). Of the 14 mechanical failures, six were treated with final fusion operations (reflecting limited further growth potential), and eight patients were treated with the intention for further lengthening. We therefore consider these eight patients to represent the true incidence of mechanical failure in our cohort (29%). The difference between the ERC length and radiographic length was found to be identical in 11% cases; 35% were overestimates, and 54% were underestimates. The median underestimate was 2.45 mm whereas the median overestimate was 3.1 mm per distraction episode. In total, 95% of all ERC distractions were within ±10 mm of the radiographic length achieved over a median of nine distraction episodes.ConclusionsOur series is the most comprehensive MCGR series published to date, and we present a mechanical failure rate of 29%. Clinicians should be mindful of the discrepancies between ERC length and radiographic measurements of rod length; other modalities may be more helpful in this regard.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years

et al. 2018

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“…Rod fracture (RF) is the most common mode of device failure following complex spinal reconstruction. 18 , 19 The longitudinal rods must provide adequate support to the instrumented spine as fusion occurs in the affected areas over the course of weeks to months. Failure at the level of these longitudinal rods may occur due to a sustained increase in motion across the fusion levels as result of delayed union or pseudoarthrosis.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical comparison between titanium and cobalt chromium rods used in a pedicle subtraction osteotomy model

Shah¹,

Walker²,

Koruprolu³

et al. 2018

Orthop Rev (Pavia)

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Instrumentation failure is a common complication following complex spinal reconstruction and deformity correction. Rod fracture is the most frequent mode of hardware failure and often occurs at or near a 3-column osteotomy site. Titanium (Ti) rods are commonly utilized for spinal fixations, however, theoretically stiffer materials, such as cobalt-chrome (CoCr) rods are also available. Despite ongoing use in clinical practice, there is little biomechanical evidence that compares the construct ability to withstand fatigue stress for Ti and Co-Cr rods. Six models using 2 polyethylene blocks each were used to simulate a pedicle subtraction osteotomy. Within each block 6.0×45 mm polyaxial screws were placed and connected to another block using either two 6.0×100 mm Ti (3 models) or CoCr rods (3 models). The rods were bent to 40° using a French bender and were secured to the screws to give a vertical height of 1.5 cm between the blocks. The blocks were fatigue tested with 700N at 4 Hz until failure. The average number of cycles to failure for the Ti rod models was 12840 while the CoCr rod models failed at a significantly higher, 58351 cycles (P=0.003). All Ti models experienced rod fracture as the mode of failure. Two out of the three CoCr models had rod fractures while the last sample failed via screw fracture at the screw-tulip junction. The risk of rod failure is substantial in the setting of long segment spinal arthrodesis and corrective osteotomy. Efforts to increase the mechanical strength of posterior constructs may reduce the occurrence of this complication. Utilizing CoCr rods in patients with pedicle subtraction osteotomy may reduce the rate of device failure during maturation of the posterior fusion mass and limit the need for supplemental anterior column support

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“…Fracture failure is not rare in orthopedic (long bone [7] , [8] and spine [9] , [10] ) and dental implants [11] , [12] . Unlike its counterpart, the cranioplasty prosthesis is not under weight-loading conditions (as orthopedic implants) or bearing obvious extra force (as dental implants).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies indicated several contributors for implant fracture: (1) inappropriate implant material [8] , (2) bad implant designs [13] , (3) inappropriate fixator selection [10] , [14] , (4) inappropriate surgical technique [9] , (5) and (6) biomechanical overload [15] , [16] . These factors are deleterious for implants fatigue resistance, which eventually lead to fracture.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous fracture of cranioplastic titanium implants without head trauma in an adult: A case report

Jiang

Wang

2016

International Journal of Surgery Case Reports

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HighlightsThe dynamic load was generated at basitemporal skull if prosthesis was not anchored to this loci.Via the parietal tuber-temporozygomatic suture line, this dynamic load was passed to the proximal pterion point region, which eventually generated fatigue effects on the prosthesis and eventually fracture.The cranioplasty prosthesis shall be well anchored onto the basitemporal skull to prevent fatigue effects of the prosthesis.

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Implant Failure of Titanium Versus Cobalt-Chromium Growing Rods in Early-onset Scoliosis

Abstract: Rod fractures occurred more commonly with titanium rods and connector fractures with cobalt-chromium rods.

Cited by 23 publications

References 12 publications

Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years

Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years

Biomechanical comparison between titanium and cobalt chromium rods used in a pedicle subtraction osteotomy model

Spontaneous fracture of cranioplastic titanium implants without head trauma in an adult: A case report

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