scholarly journals The impact of compressive force magnitude on the in vitro neutral zone range and passive stiffness during a flexion–extension range of motion test

2015 ◽  
Vol 2 (1) ◽  
pp. 1014253
Author(s):  
Mamiko Noguchi ◽  
Chad E. Gooyers ◽  
Michael W.R. Holmes ◽  
Jack P. Callaghan
Keyword(s):  
Range Of Motion ◽  
Compressive Force ◽  
Neutral Zone ◽  
Passive Stiffness ◽  
Force Magnitude ◽  
Flexion Extension ◽  
The Impact

Biomechanics of a Novel Minimally Invasive Lumbar Interspinous Spacer: Effects on Kinematics, Facet Loads, and Foramen Height

2010 ◽  
Vol 66 (suppl_1) ◽  
pp. ons-126-ons-133 ◽  
Author(s):  
Bruno C.R. Lazaro ◽  
Leonardo B.C. Brasiliense ◽  
Anna G.U. Sawa ◽  
Phillip M. Reyes ◽  
Nicholas Theodore ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Axial Rotation ◽  
Surface Strain ◽  
Interspinous Spacer ◽  
Instantaneous Axis Of Rotation ◽  
Flexion Extension ◽  
Before And After ◽  
Biomechanical Effect ◽  
Foraminal Height

Abstract Objective: To study the alteration to normal biomechanics after insertion of a lumbar interspinous spacer (ISS) in vitro by nondestructive cadaveric flexibility testing. Methods: Seven human cadaveric specimens were studied before and after ISS placement at L1–L2. Angular range of motion, lax zone, stiff zone, sagittal instantaneous axis of rotation (IAR), foraminal height, and facet loads were compared between conditions. Flexion, extension, lateral bending, and axial rotation were induced using pure moments (7.5 Nm maximum) while recording motion optoelectronically. The IAR was measured during loading with a 400 N compressive follower. Foraminal height changes were calculated using rigid body methods. Facet loads were assessed from surface strain and neural network analysis. Results: After ISS insertion, range of motion and stiff zone during extension were significantly reduced (P < .01). Foraminal height was significantly reduced from flexion to extension in both normal and ISS-implanted conditions; there was significantly less reduction in foraminal height during extension with the ISS in place. The ISS reduced the mean facet load by 30% during flexion (P < .02) and 69% during extension (P < .015). The IAR after ISS implantation was less than 1 mm from the normal position (P > .18). Conclusion: The primary biomechanical effect of the ISS was reduced extension with associated reduced facet loads and smaller decrease in foraminal height. The ISS had little effect on sagittal IAR or on motion or facet loads in other directions.

A comparison of single and incremental impact approaches for producing experimental thoracolumbar burst fractures

2007 ◽  
Vol 7 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Xiang-Yang Wang ◽  
Li-Yang Dai ◽  
Hua-Zi Xu ◽  
Yong-Long Chi
Keyword(s):  
Burst Fracture ◽  
Axial Rotation ◽  
Similar Degree ◽  
Thoracolumbar Burst Fractures ◽  
Single Impact ◽  
Burst Fractures ◽  
Flexion Extension ◽  
The Impact ◽  
Flexibility Parameters

Object. Experimental burst fracture models are often developed by using either single or incremental impacts. In both protocols, the weight-drop technique produces the impact. However, to the authors' knowledge in no study have researchers attempted to compare the equivalence of the spine burst fracture produced using the different impact protocols. This study was performed to investigate whether the single and incremental trauma approaches produce equivalent degrees of severity in thoracolumbar burst fractures. Methods. Twenty bovine thoracolumbar spines comprising three vertebrae were divided evenly into the single impact and incremental impact groups. The specimens in the incremental impact group were subjected to three axial compressive impacts of increasing energy (78.4, 107.8, and 137.2 J), whereas specimens in the other group were subjected to a single impact (137.2 J). Before and after the final trauma, multidirectional flexibility of each specimen was measured under flexion/extension, right/left lateral bending, and right/left axial rotation, thus quantifying the instability of the fracture. The flexibility parameters were then compared between the two groups. Results. A significant increase in flexibility parameters was found after the final trauma in both groups, indicating the instability of the spine (p < 0.01). No significant differences in flexibility parameters were observed in either intact status or injured status between the two groups (p > 0.05). Conclusions. In this study the authors have confirmed that the single and incremental impact protocols produced a similar degree of severity in producing an in vitro bovine burst fracture. The results of this study support the use of the incremental impact protocol in future experimental biomechanical studies.

scholarly journals A Comparative Study of Efficacy and Functionality of Ten Commercially Available Wrist-Hand Orthoses in Healthy Females: Wrist Range of Motion and Grip Strength Analysis

2021 ◽  
Vol 2 ◽  
Author(s):  
Alejandra Aranceta-Garza ◽  
Karyn Ross
Keyword(s):  
Range Of Motion ◽  
Grip Strength ◽  
Evidence Base ◽  
Secondary Outcome ◽  
Functional Study ◽  
Strength Analysis ◽  
Hand Position ◽  
Ulnar Deviation ◽  
Flexion Extension ◽  
The Impact

Objective: Wrist-hand orthoses (WHOs) are prescribed for a range of musculoskeletal/neurological conditions to optimise wrist/hand position at rest and enhance performance by controlling its range of motion (ROM), improving alignment, reducing pain, and optimising grip strength. The objective of this research was to study the efficacy and functionality of ten commercially available WHOs on wrist ROM and grip strength.Design: Randomised comparative functional study of the wrist/hand with and without WHOs.Participants: Ten right-handed female participants presenting with no underlying condition nor pain affecting the wrist/hand which could influence motion or grip strength. Each participant randomly tested ten WHOs; one per week, for 10 weeks.Main outcome measures: The primary outcome was to ascertain the impact of WHOs on wrist resting position and flexion, extension, radial, and ulnar deviation. A secondary outcome was the impact of the WHOs on maximum grip strength and associated wrist position when this was attained.Results: From the 2,400 tests performed it was clear that no WHO performed effectively or consistently across participants. The optimally performing WHO for flexion control was #3 restricting 86.7%, #4 restricting 76.7% of extension, #9 restricting 83.5% of radial deviation, and #4 maximally restricting ulnar deviation. A grip strength reduction was observed with all WHOs, and ranged from 1.7% (#6) to 34.2% (#4).Conclusion: WHOs did not limit movement sufficiently to successfully manage any condition requiring motion restriction associated with pain relief. The array of motion control recorded might be a contributing factor for the current conflicting evidence of efficacy for WHOs. Any detrimental impact on grip strength will influence the types of activities undertaken by the wearer. The design aspects impacting wrist motion and grip strength are multifactorial, including: WHO geometry; the presence of a volar bar; material of construction; strap design; and quality of fit. This study raises questions regarding the efficacy of current designs of prefabricated WHOs which have remained unchanged for several decades but continue to be used globally without a robust evidence-base to inform clinical practise and the prescription of these devices. These findings justify the need to re-design WHOs with the goal of meeting users' needs.

Distribution of in vivo and in vitro range of motion following 1-level arthroplasty with the CHARITÉ artificial disc compared with fusion

2008 ◽  
Vol 8 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Bryan W. Cunningham ◽  
Paul C. McAfee ◽  
Fred H. Geisler ◽  
Gwen Holsapple ◽  
Karen Adams ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Pedicle Screws ◽  
Investigational Device Exemption ◽  
Flexion Extension ◽  
Level Fusion ◽  
Vitro Data ◽  
In Vitro Data ◽  
Time Point

Object One of the goals of lumbar arthroplasty is to restore and maintain range of motion (ROM) and to protect adjacent levels from abnormal motion, which may be a factor in transition syndrome following arthrodesis. In this study, in vitro ROM results were compared with in vivo, 2-year postoperative radiographic ROM evaluations. Methods Radiographs of patients enrolled in the CHARITÉ investigational device exemption study were analyzed at baseline and at 2 years postoperatively. The ROM in flexion/extension at the implanted and adjacent levels was measured, normalized, and compared with ROM results obtained using cadaver (in vitro) evaluations. Results Preoperative ROM distributions in patients enrolled for arthroplasty or fusion at the L4–5 level was as follows: 28% motion was observed at L3–4, 35% at L4–5 and 37% at L5–S1. Following a one-level arthroplasty at L4–5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 36% at L3–4, 30% at L4–5 and 35% at L5–S1. Following a one-level fusion with BAK and pedicle screws at L4–5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 45% at L3–4, 9% at L4–5 and 46% at L5–S1. Conclusions The baseline as well as the 2-year in vivo data confirmed previously published in vitro data. One-level arthroplasty was shown herein to replicate the normal distribution of motion of the intact spine.

scholarly journals Comprehensive biomechanical analysis of three reconstruction techniques following total sacrectomy: an in vitro human cadaveric model

2017 ◽  
Vol 27 (5) ◽  
pp. 570-577 ◽  
Author(s):  
Mohamed Macki ◽  
Rafael De la Garza-Ramos ◽  
Ashley A. Murgatroyd ◽  
Kenneth P. Mullinix ◽  
Xiaolei Sun ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Axial Compression ◽  
Axial Rotation ◽  
Biomechanical Analysis ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Iliac Screws ◽  
Intact Condition ◽  
Cadaveric Model

OBJECTIVEAggressive sacral tumors often require en bloc resection and lumbopelvic reconstruction. Instrumentation failure and pseudarthrosis remain a clinical concern to be addressed. The objective in this study was to compare the biomechanical stability of 3 distinct techniques for sacral reconstruction in vitro.METHODSIn a human cadaveric model study, 8 intact human lumbopelvic specimens (L2–pelvis) were tested for flexion-extension range of motion (ROM), lateral bending, and axial rotation with a custom-designed 6-df spine simulator as well as axial compression stiffness with the MTS 858 Bionix Test System. Biomechanical testing followed this sequence: 1) intact spine; 2) sacrectomy (no testing); 3) Model 1 (L3–5 transpedicular instrumentation plus spinal rods anchored to iliac screws); 4) Model 2 (addition of transiliac rod); and 5) Model 3 (removal of transiliac rod; addition of 2 spinal rods and 2 S-2 screws). Range of motion was measured at L4–5, L5–S1/cross-link, L5–right ilium, and L5–left ilium.RESULTSFlexion-extension ROM of the intact specimen at L4–5 (6.34° ± 2.57°) was significantly greater than in Model 1 (1.54° ± 0.94°), Model 2 (1.51° ± 1.01°), and Model 3 (0.72° ± 0.62°) (p < 0.001). Flexion-extension at both the L5–right ilium (2.95° ± 1.27°) and the L5–left ilium (2.87° ± 1.40°) for Model 3 was significantly less than the other 3 cohorts at the same level (p = 0.005 and p = 0.012, respectively). Compared with the intact condition, all 3 reconstruction groups statistically significantly decreased lateral bending ROM at all measured points. Axial rotation ROM at L4–5 for Model 1 (2.01° ± 1.39°), Model 2 (2.00° ± 1.52°), and Model 3 (1.15° ± 0.80°) was significantly lower than the intact condition (5.02° ± 2.90°) (p < 0.001). Moreover, axial rotation for the intact condition and Model 3 at L5–right ilium (2.64° ± 1.36° and 2.93° ± 1.68°, respectively) and L5–left ilium (2.58° ± 1.43° and 2.93° ± 1.71°, respectively) was significantly lower than for Model 1 and Model 2 at L5–right ilium (5.14° ± 2.48° and 4.95° ± 2.45°, respectively) (p = 0.036) and L5–left ilium (5.19° ± 2.34° and 4.99° ± 2.31°) (p = 0.022). Last, results of the axial compression testing at all measured points were not statistically different among reconstructions.CONCLUSIONSThe addition of a transverse bar in Model 2 offered no biomechanical advantage. Although the implementation of 4 iliac screws and 4 rods conferred a definitive kinematic advantage in Model 3, that model was associated with significantly restricted lumbopelvic ROM.

Computed Tomographic Evaluation of Adjacent Segment Motion after Ex Vivo Fusion of Equine Third and Fourth Cervical Vertebrae

2019 ◽  
Vol 33 (01) ◽  
pp. 001-008
Author(s):  
Nicole Schulze ◽  
Anna Ehrle ◽  
Renate Weller ◽  
Guido Fritsch ◽  
Jennifer Gernhardt ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Ex Vivo ◽  
Cervical Vertebrae ◽  
Adjacent Segment ◽  
Vertebral Fusion ◽  
Computed Tomographic ◽  
Surgical Fusion ◽  
Flexion Extension ◽  
Cervical Stenotic Myelopathy ◽  
The Impact

Objective Surgical fusion of vertebral segments is a treatment option for horses with cervical stenotic myelopathy or cervical fracture.Degenerative disease affecting adjacent vertebral segments is a reported complication following surgical vertebral fusion in other species, termed adjacent segment disease. The aim of this study was to evaluate the impact of cervical vertebral fusion on the biomechanics of adjacent vertebral segments in the horse. Study Design Neck specimens of 12 horses were assessed using computed tomographic imaging. Range of motion (ROM) was determined by measuring the maximum sagittal flexion, extension and lateral bending between C2 and C5. C3/4 was subsequently fused using a standard locking compression plate and locking head screws and computed tomographic scans and ROM measurements were repeated. Results Prior to intervertebral fusion, a significant increase in ROM along the vertebral segments from cranial to caudal was observed. Range of motion measurements of C3/4 decreased significantly after fusion (p = 0.01).Range of motion of the adjacent segments (C2/3 and C4/5) did not change significantly after fusion. Conclusion Fusion of one cervical intervertebral joint did not affect the ROM of the adjacent vertebral segments. Further research investigating the implications of vertebral fusion on the intervertebral pressure in the equine patient is indicated.

scholarly journals An In Vitro Biomechanical Evaluation of a Lateral Lumbar Interbody Fusion Device With Integrated Lateral Modular Plate Fixation

2020 ◽  
pp. 219256822090561
Author(s):  
Ryan DenHaese ◽  
Anup Gandhi ◽  
Chris Ferry ◽  
Sam Farmer ◽  
Randall Porter
Keyword(s):  
Range Of Motion ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Plate Fixation ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Biomechanical Study ◽  
Flexion Extension ◽  
Bilateral Pedicle Screw

Study Design: In vitro cadaveric biomechanical study. Objective: Biomechanically characterize a novel lateral lumbar interbody fusion (LLIF) implant possessing integrated lateral modular plate fixation (MPF). Methods: A human lumbar cadaveric (n = 7, L1-L4) biomechanical study of segmental range-of-motion stiffness was performed. A ±7.5 Nċm moment was applied in flexion/extension, lateral bending, and axial rotation using a 6 degree-of-freedom kinematics system. Specimens were tested first in an intact state and then following iterative instrumentation (L2/3): (1) LLIF cage only, (2) LLIF + 2-screw MPF, (3) LLIF + 4-screw MPF, (4) LLIF + 4-screw MPF + interspinous process fixation, and (5) LLIF + bilateral pedicle screw fixation. Comparative analysis of range-of-motion outcomes was performed between iterations. Results: Key biomechanical findings: (1) Flexion/extension range-of-motion reduction with LLIF + 4-screw MPF was significantly greater than LLIF + 2-screw MPF ( P < .01). (2) LLIF with 2-screw and 4-screw MPF were comparable to LLIF with bilateral pedicle screw fixation in lateral bending and axial rotation range-of-motion reduction ( P = 1.0). (3) LLIF + 4-screw MPF and supplemental interspinous process fixation range-of-motion reduction was comparable to LLIF + bilateral pedicle screw fixation in all directions ( P ≥ .6). Conclusions: LLIF with 4-screw MPF may provide inherent advantages over traditional 2-screw plating modalities. Furthermore, when coupled with interspinous process fixation, LLIF with MPF is a stable circumferential construct that provides biomechanical utility in all principal motions.

scholarly journals The impact of different artificial disc heights during total cervical disc replacement: an in vitro biomechanical study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Xiao-Fei Wang ◽  
Yang Meng ◽  
Hao Liu ◽  
Bei-Yu Wang ◽  
Ying Hong
Keyword(s):  
Range Of Motion ◽  
Facet Joint ◽  
Biomechanical Study ◽  
Disc Height ◽  
Cervical Disc ◽  
Artificial Disc ◽  
Lateral Bending ◽  
Cervical Disc Replacement ◽  
Flexion Extension

Abstract Background The principles of choosing an appropriate implant height remain controversial in total cervical disc replacement (TDR). By performing an in vitro biomechanical study and exploring the biomechanical impact of implant height on facet joint and motion function, the study aimed to offer valid proposals regarding implant height selection during TDR. Methods A total of 6 fresh-frozen male cadaveric cervical spines (C2–C7) with 5 mm intervertebral disc height at C5/6 level were enrolled in the study. Specimens with the intact condition and with different height artificial discs were tested. Facet joint pressures and range of motion under each condition were recorded using a specialized machine. Results The artificial disc heights that were involved in this study were 5 mm, 6 mm, and 7 mm. The range of motion decreased along with the increment of implant height, while facet joint pressure showed an opposite trend. Specimens with a 5 mm implant height could provide a similar range of motion (11.8° vs. 12.2° in flexion-extension, 8.7° vs. 9.0° in rotation, 7.9° vs. 8.2° in lateral bending) and facet joint pressure (27.8 psi vs. 25.2 psi in flexion, 59.7 psi vs. 58.9 psi in extension, 24.0 psi vs. 22.7 psi in rotation, 32.0 psi vs. 28.8 psi in lateral bending) compared with intact specimens. Facet joint pressure of specimens with 6 mm implant height (≥ 1 mm in height) increased during flexion at the C5–6 segment (30.4 psi vs. 25.2 psi, P = 0.076). However, specimens with 7 mm implant height (≥ 2 mm in height) showed a significant reduction in motion (9.5° vs. 12.2° in flexion-extension, P < 0.001) and increment of facet joint pressure at C5–6 segment (44.6 psi vs. 25.2 psi in flexion, 90.3 psi vs. 58.9 psi in extension, P < 0.0001) and adjacent segments. Conclusions This study suggested that an appropriate artificial disc height can achieve near-normal biomechanical properties and is recommended. We should be very cautious when using artificial discs ≥ 1 mm in height compared to normal. However, implants ≥ 2 mm in height compared to normal significantly increased the facet joint pressure and decreased the range of motion; therefore, it should not be used in clinical practice.

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