Thiel-fixation preserves the non-linear load–deformation characteristic of spinal motion segments, but increases their flexibility

Wilke, Hans–Joachim; Werner, Karin; Häussler, K.; Reinehr, Michael; Böckers, Tobias M.

doi:10.1016/j.jmbbm.2011.07.013

Cited by 55 publications

(31 citation statements)

References 24 publications

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“…In comparison with unloaded knees, the magnitude of rotation was greater and occurred earlier on weight bearing. Whole cadavers were investigated and fixed according to the method by Thiel that is well-known for its physiological soft-tissue characters and excellent movement patterns [53]. Favorably, using whole cadavers assesses the influence of the entire surrounding soft-tissues and muscles, the hip, as well as the muscles associated with the hip, which are often neglected in laboratory studies.…”

Section: Discussionmentioning

confidence: 99%

Influence of Component Rotation in Total Knee Arthroplasty on Tibiofemoral Kinematics—A Cadaveric Investigation

Maderbacher¹,

Keshmiri²,

Springorum³

et al. 2017

The Journal of Arthroplasty

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Section: Discussionmentioning

confidence: 99%

Influence of Component Rotation in Total Knee Arthroplasty on Tibiofemoral Kinematics—A Cadaveric Investigation

Maderbacher¹,

Keshmiri²,

Springorum³

et al. 2017

The Journal of Arthroplasty

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“…In the spine, the motion/force relationship becomes nonlinear when intervertebral segments approach anatomic maximum values. 29 In soft tissue, motion/force relationships are nonlinear, with greater displacement/deformation requiring disproportionately greater force. 30 As a combined result of these three factors, the relationship between laryngoscope force and cervical spine motion during intubation is non-linear and differs between laryngoscopes.…”

Section: Discussionmentioning

confidence: 99%

“…In vitro studies of isolated cervical spine segments 29 and soft tissues 30 show that, because of tissue viscoelastic properties, motion/force relationships change over time and include a history effect ( i.e ., they are deformation cycle dependent). If major preconditioning effects had been present in our study, one would expect that Macintosh-Airtraq differences in force, motion, and motion/force ratios should differ as a function of intubation sequence.…”

Section: Discussionmentioning

confidence: 99%

Intubation Biomechanics

et al. 2014

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Introduction Laryngoscopy and endotracheal intubation in the presence of cervical spine instability may put patients at risk of cervical cord injury. Nevertheless, the biomechanics of intubation (cervical spine motion as a function of applied force) have not been characterized. This study characterized and compared the relationship between laryngoscope force and cervical spine motion using two laryngoscopes hypothesized to differ in force. Methods Fourteen adults undergoing elective surgery were intubated twice (Macintosh, Airtraq). During each intubation, laryngoscope force, cervical spine motion, and glottic view were recorded. Force and motion were referenced to a pre-intubation baseline (stage 1) and were characterized at three stages: stage 2 (laryngoscope introduction); stage 3 (best glottic view); stage 4 (endotracheal tube in trachea). Results Maximal force and motion occurred at stage 3, and differed between the Macintosh and Airtraq: 1) Force: 48.8±15.8 vs. 10.4±2.8 N, respectively; P=0.0001; 2) occiput-C5 extension: 29.5±8.5 vs. 19.1±8.7 degrees, respectively; P=0.0023. Between stages -2 and -3, the motion/force ratio differed between Macintosh and Airtraq: 0.5±0.2 vs. 2.0±1.4 degrees/N, respectively; P=0.0006. Discussion The relationship between laryngoscope force and cervical spine motion is: 1) non-linear and 2) differs between laryngoscopes. Differences between laryngoscopes in motion/force relationships are likely due to: 1) laryngoscope-specific cervical extension needed for intubation, 2) laryngoscope-specific airway displacement/deformation needed for intubation, and 3) cervical spine and airway tissue viscoelastic properties. Cervical spine motion during endotracheal intubation is not directly proportional to force. Low force laryngoscopes cannot be assumed to result in proportionally low cervical spine motion.

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“…19,20 Accordingly, in virtually all in vitro studies of segmental spinal motion, force/motion characteristics are determined only after at least two load cycles. 20,21,47,48 We had anticipated that, because of in vitro tissue preconditioning, cadaver intubation biomechanics might change with repeated intubations. However, the effect was greater than anticipated, as evidenced by marked deformation of cadaver airway tissue (tongue) after high force Macintosh intubations.…”

Section: Discussionmentioning

confidence: 99%

“…These observations differ from in vitro studies (non-living tissues) in which motion/force relationships change with repeated applications of force, particularly during the first few (1–3) load application cycles. 19,20 If repeated intubations change cadaver biomechanical properties, then cervical spine motion observed during the n th intubation could differ from what would be observed during the first intubation, potentially confounding the data. Therefore, in Experiment 1, we measured intubation forces and cervical spine motion in cadavers that underwent intubations with two different laryngoscopes ( e.g ., Macintosh and Airtraq [Airtraq LLC, Fenton, MO]) and compared these values to those obtained in a prior clinical study in which patients underwent intubations with the same two devices.…”

Section: Introductionmentioning

confidence: 99%

Intubation Biomechanics

et al. 2015

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Introduction The aims of this study were to characterize: 1) cadaver intubation biomechanics, including the effect of repeated intubations; and 2) the relationship between intubation force and the motion of an injured cervical segment. Methods Fourteen cadavers were serially intubated using force-sensing Macintosh and Airtraq laryngoscopes in random order, with simultaneous cervical spine motion recorded with lateral fluoroscopy. Motion of the C1-C2 segment was measured in the intact and injured state (Type II odontoid fracture). Injured C1-C2 motion was proportionately corrected for changes in intubation forces that occurred with repeated intubations. Results Cadaver intubation biomechanics were comparable to those of patients in all parameters other than C2-C5 extension. In cadavers, intubation force (Set 2/Set1 force ratio = 0.61 [95% CI: 0.46, 0.81]; P=0.002) and Oc-C5 extension (Set 2 –Set 1 difference = −6.1 degrees [95% CI: −11.4, −0.9]; P=0.025) decreased with repeated intubations. In cadavers, C1-C2 extension did not differ: 1) between intact and injured states; or 2) in the injured state, between laryngoscopes (with and without force correction). With force correction, in the injured state, C1-C2 subluxation was greater with the Airtraq (mean difference 2.8 mm [95% CI: 0.7, 4.9 mm]; P=0.004). Discussion With limitations, cadavers may be clinically relevant models of intubation biomechanics and cervical spine motion. In the setting of a Type II odontoid fracture, C1-C2 motion during intubation with either the Macintosh or Airtraq does not appear to greatly exceed physiologic values or to have a high likelihood of hyperextension or direct cord compression.

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Thiel-fixation preserves the non-linear load–deformation characteristic of spinal motion segments, but increases their flexibility

Cited by 55 publications

References 24 publications

Influence of Component Rotation in Total Knee Arthroplasty on Tibiofemoral Kinematics—A Cadaveric Investigation

Influence of Component Rotation in Total Knee Arthroplasty on Tibiofemoral Kinematics—A Cadaveric Investigation

Intubation Biomechanics

Intubation Biomechanics

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