Spinal Fusion Implant Stiffness Affects Load Sharing

Peterson, Josh; Chlebek, Carolyn; Ledet, Eric H.

doi:10.1016/j.spinee.2016.07.348

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… 17 Recently, instrumented interbody implants have demonstrated that the mechanical properties of the implants themselves dictate load sharing, which can strongly affect the rate and quality of fusion. 70 …”

Section: Introductionmentioning

confidence: 99%

Smart implants in orthopedic surgery, improving patient outcomes: a review

Ledet

Liddle

Kradinova

et al. 2018

IEH

View full text Add to dashboard Cite

Smart implants are implantable devices that provide not only therapeutic benefits but also have diagnostic capabilities. The integration of smart implants into daily clinical practice has the potential for massive cost savings to the health care system. Applications for smart orthopedic implants have been identified for knee arthroplasty, hip arthroplasty, spine fusion, fracture fixation and others. To date, smart orthopedic implants have been used to measure physical parameters from inside the body, including pressure, force, strain, displacement, proximity and temperature. The measurement of physical stimuli is achieved through integration of application-specific technology with the implant. Data from smart implants have led to refinements in implant design, surgical technique and strategies for postoperative care and rehabilitation. In spite of decades of research, with very few exceptions, smart implants have not yet become a part of daily clinical practice. This is largely because integration of current sensor technology necessitates significant modification to the implants. While the technology underlying smart implants has matured significantly over the last several decades, there are still significant technical challenges that need to be overcome before smart implants become part of mainstream health care. Sensors for next-generation smart implants will be small, simple, robust and inexpensive and will necessitate little to no modification to existing implant designs. With rapidly advancing technology, the widespread implementation of smart implants is near. New sensor technology that minimizes modifications to existing implants is the key to enabling smart implants into daily clinical practice.

show abstract

Section: Introductionmentioning

confidence: 99%

Smart implants in orthopedic surgery, improving patient outcomes: a review

Ledet

Liddle

Kradinova

et al. 2018

IEH

View full text Add to dashboard Cite

show abstract

“…Using in vitro biomechanical testing, plate stiffness was shown to transmit a majority of the loads through the anterior cervical plate, shielding the interbody space from the mechanical stimulus that promotes bone formation and remodeling. 25 Previous comparisons between perioperative and radiographic outcomes between stand-alone cervical fixation and anterior plate-cage constructs show no differences in the rates of nonunion, loss of correction, or subsidence between groups. 6 In line with this, the results of the current study demonstrate that single-level interbody cage placement without plate supplementation adjacent to the plate construct has sufficient stability and can achieve fusion.…”

Section: Discussionmentioning

confidence: 91%

Interbody Cage Placement Without Plate Supplementation Adjacent to Plated Segments in Multilevel Anterior Cervical Decompression and Fusion

Odate¹,

Shikata²

2023

Spine

View full text Add to dashboard Cite

Study Design. A retrospective cohort study. Objective. To evaluate the clinical efficacy and safety of hybrid anterior cervical fixation, focusing on stand-alone segments. Summary of Background Data. In the treatment of multilevel cervical stenosis, the number of segments fixed using a plate is limited by placing an interbody cage without plate supplementation at one end of the surgical segment to reduce long plate-related problems. However, the stand-alone segment may experience cage extrusion, subsidence, cervical alignment deterioration, and nonunion. Methods. Patients who underwent three-segment or four-segment fixation for cervical degenerative disease and completed one-year follow-up were included in this study. Patients were divided into two groups: a cranial group, with stand-alone segments located at the cranial end adjacent to plated segments, and a caudal group, with stand-alone segments located at the caudal end. Differences in radiographic outcomes between the groups were evaluated. Fusion was defined using dynamic radiographs or computed tomography. To identify factors associated with nonunion in stand-alone segments, multivariable logistic regression analyses were performed. To identify factors associated with cage subsidence, multiple regression analyses were performed. Results. A total of 116 patients (mean age, 59±11 y; 72% male; mean fixed segments, 3.7±0.5 segments) were included in this study. No case showed cage extrusion or plate dislodgement. In stand-alone segments, the fusion rate was significantly lower in the caudal group than in the cranial group (76% vs. 93%, P=0.019). Change in the cervical sagittal vertical axis was worse in the caudal group than in the cranial group (2.7±12.3 mm vs. −2.7±8.1 mm, P=0.006). One caudal group patient required additional surgery because of nonunion at the stand-alone segment. Multivariable logistic regression indicated factors associated with nonunion included the location of the stand-alone segment (caudal end: OR 4.67, 95% CI, 1.29–16.90), larger pre-disk space range of motion (OR 1.15, 95% CI, 1.04–1.27), and lower preoperative disk space height (OR 0.57, 95% CI, 0.37–0.87). Multiple regression analysis indicated that higher cage height and lower pre-disk space height were associated with cage subsidence. Conclusion. Hybrid anterior cervical fixation with stand-alone interbody cage placement adjacent to plated segments may avoid long plate-related problems. Our results suggest that the cranial end of the construct may be more suitable for the stand-alone segment than the caudal end.

show abstract

“…15–18 There is a correlation between implant stiffness, instantaneous axis of rotation, and interbody loading. 15,16 If too rigid, the plate will stress-shield, reverse load the graft, and have a high likelihood of causing subsidence and graft failure or screw loosening. 19–22 If too flexible, excess motion between the graft and endplates will favor pseudarthrosis over fusion.…”

Section: Introductionmentioning

confidence: 99%