Construct Stability of C2 Replacement Strategies

2003 ◽  
Author(s):  
Christian M. Puttlitz ◽  
Robert P. Melcher ◽  
Vedat Deviren ◽  
Dezsoe Jeszenszky ◽  
Ju¨rgen Harms
Keyword(s):  
Repeated Measures ◽  
Posterior Instrumentation ◽  
Statistical Significance ◽  
Axial Rotation ◽  
Posterior Fixation ◽  
Camera Motion ◽  
Anterior Plate ◽  
Intact Specimen ◽  
Strut Graft ◽  
Significant Difference

Reconstruction of C2 after tumor destruction and resection remains a significant challenge. Most constructs utilize a strutgraft with plate or screw fixation. A novel C2 prosthesis combining a titanium mesh cage with bilateral C1 shelves and a T-plate has been used successfully in 18 patients. Supplemental posterior instrumentation includes C0-C3 or C1-C3. Biomechanical comparisons of this C2 prosthesis with traditional fixation options have not been reported. Five fresh-frozen human cadaveric cervical spines (C0-C5) were tested intact. Next, the C2 prosthesis, and strut graft and anterior plate constructs were tested with occiput-C3 and C1-C3 posterior fixation. Pure moment loads (up to 1.5 N-m) were applied in flexion and extension, lateral bending, and axial rotation. C1-C3 motion was evaluated using 3 camera motion analysis. Statistical significance was evaluated using one-way repeated measures ANOVA with Student-Newman-Keuls post hoc pairwise comparisons. All constructs provided a statistically significant decrease in motion in this C2 corpectomy model as compared to the intact condition. There was no significant difference in C1-C3 motion between the 4 constructs, regardless of whether the occiput was included in the fixation. Under these loading conditions, both the C2 prostheisis and strut-graft-plate constructs provided initial C1-C3 stability beyond that of the intact specimen. The occiput does not need to be included in the posterior instrumentation.

Biomechanical comparison of anterior Caspar plate and three-level posterior fixation techniques in a human cadaveric model

1993 ◽  
Vol 79 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Vincent C. Traynelis ◽  
Paul A. Donaher ◽  
Robert M. Roach ◽  
H. Kojimoto ◽  
Vijay K. Goel
Keyword(s):  
Cervical Spine ◽  
Repeated Measures ◽  
Plate Fixation ◽  
Axial Rotation ◽  
Posterior Fixation ◽  
Lateral Bending ◽  
Anterior Plate ◽  
Content Type ◽  
Cervical Spine Injuries ◽  
Flexion Extension

✓ Traumatic cervical spine injuries have been successfully stabilized with plates applied to the anterior vertebral bodies. Previous biomechanical studies suggest, however, that these devices may not provide adequate stability if the posterior ligaments are disrupted. To study this problem, the authors simulated a C-5 teardrop fracture with posterior ligamentous instability in human cadaveric spines. This model was used to compare the immediate biomechanical stability of anterior cervical plating, from C-4 to C-6, to that provided by a posterior wiring construct over the same levels. Stability was tested in six modes of motion: flexion, extension, right and left lateral bending, and right and left axial rotation. The injured/plate-stabilized spines were more stable than the intact specimens in all modes of testing. The injured/posterior-wired specimens were more stable than the intact spines in axial rotation and flexion. They were not as stable as the intact specimens in the lateral bending or extension testing modes. The data were normalized with respect to the motion of the uninjured spine and compared using repeated measures of analysis of variance, the results of which indicate that anterior plating provides significantly more stability in extension and lateral bending than does posterior wiring. The plate was more stable than the posterior construct in flexion loading; however, the difference was not statistically significant. The two constructs provide similar stability in axial rotation. This study provides biomechanical support for the continued use of bicortical anterior plate fixation in the setting of traumatic cervical spine instability.

scholarly journals Dietary Intake and Nitrogen Balance in British Army Infantry Recruits Undergoing Basic Training

Nutrients ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2125 ◽  
Author(s):  
Shaun Chapman ◽  
Alex J. Rawcliffe ◽  
Rachel Izard ◽  
Kimberley Jacka ◽  
Hayley Tyson ◽  
...  
Keyword(s):  
Dietary Intake ◽  
Nitrogen Balance ◽  
Repeated Measures ◽  
Protein Intake ◽  
Statistical Significance ◽  
British Army ◽  
Basic Training ◽  
Training Centre ◽  
Significant Difference ◽  
G 11

We assessed dietary intake and nitrogen balance during 14 weeks of Basic Training (BT) in British Army Infantry recruits. Nineteen men (mean ± SD: age 19.9 ± 2.6 years, height: 175.7 ± 6.5 cm, body mass 80.3 ± 10.1 kg) at the Infantry Training Centre, Catterick (ITC(C)) volunteered. Nutrient intakes and 24-h urinary nitrogen balance were assessed in weeks 2, 6 and 11 of BT. Nutrient intake was assessed using researcher-led weighed food records and food diaries, and Nutritics professional dietary software. Data were compared between weeks using a repeated-measures analysis of variance (ANOVA) with statistical significance set at p ≤ 0.05. There was a significant difference in protein intake (g) between weeks 2 and 11 of BT (115 ± 18 vs. 91 ± 20 g, p = 0.02, ES = 1.26). There was no significant difference in mean absolute daily energy (p = 0.44), fat (p = 0.79) or carbohydrate (CHO) intake (p = 0.06) between weeks. Nitrogen balance was maintained in weeks 2, 6 and 11, but declined throughout BT (2: 4.6 ± 4.1 g, 6: 1.6 ± 4.5 g, 11: −0.2 ± 5.5 g, p = 0.07). A protein intake of 1.5 g·kg−1·d−1 may be sufficient in the early stages of BT, but higher intakes may be individually needed later on in BT.

Effect of Presurgical Nasoalveolar Molding on Nasal Symmetry in Unilateral Complete Cleft Lip/Palate Patients after Primary Cheiloplasty without Concomitant Nasal Cartilage Dissection

2018 ◽  
Vol 55 (7) ◽  
pp. 935-940 ◽  
Author(s):  
Zhigang Liang ◽  
Jinfeng Yao ◽  
Philip K.T. Chen ◽  
Cangshang Zheng ◽  
Jiying Yang
Keyword(s):  
Repeated Measures ◽  
Cleft Lip ◽  
Early Stage ◽  
Statistical Significance ◽  
Deformity Correction ◽  
Nasal Cartilage ◽  
Significant Difference ◽  
Cleft Lip Palate ◽  
Nasoalveolar Molding

Objective: The objective of this study was to assess the efficacy of presurgical nasoalveolar molding (PNAM) on long-term nasal symmetry and shaping after primary cheiloplasty in patients with unilateral complete cleft lip/palate (UCL/P). Design: This was a two-group, parallel, retrospective, randomized clinical trial. Setting: The setting for this study was the Chang Gung Craniofacial Center in Taoyuan, Taiwan. Patients: Patients were divided into one of the following two groups: infants with UCL/P who underwent PNAM (PNAM group, n = 42) and infants with UCL/P who did not undergo PNAM (non-PNAM group, n = 42). Interventions: Interventions included PNAM and primary cheiloplasty without nasal cartilage dissection. Main Outcome Measures: In this study, 4- to 5-year postoperative full-face and submental oblique photographs were taken of all patients and scored from 1 to 5 points by 10 medical evaluators. The scores were statistically analyzed using repeated-measures analysis of variance, and P < .05 was considered to represent statistical significance. Results: After 1 to 3 months of PNAM but before primary cheiloplasty, the displaced nasal and alveolar cartilage showed obvious improvement. However, the scores in the PNAM and non-PNAM groups at 4 to 5 years postoperatively were 66.62 ± 14.25 and 66.31 ± 15.08, respectively. There was no significant difference between the two groups ( F = 0.009, P = .923). Conclusion: PNAM as an early-stage adjunctive therapy for nasal deformity correction is beneficial before primary cheiloplasty, but it is insufficient to maintain long-term nostril symmetry after primary cheiloplasty without nasal cartilage dissection.

scholarly journals Does Cervicogenic Headache Result in the Presence of Neural Tension, and Does this Affect the Position and Mobility of Atlas?

2021 ◽  
Vol 6 (1) ◽  
Keyword(s):  
Statistical Significance ◽  
Axial Rotation ◽  
Cervicogenic Headache ◽  
Upper Cervical Spine ◽  
Slump Test ◽  
Significant Difference ◽  
Cervicogenic Headaches ◽  
Upper Cervical ◽  
The Right ◽  
Straight Leg Raise

Background: Cervicogenic headaches (CGH) can be the result of dysfunction of the upper cervical spine. Due to the soft tissue connection between muscle, cervical fascia, and dura, this region might contribute to the development of CGH. Objective: Evaluate if subjects with CGH have neural tension signs. The secondary objective was to investigate if a correlation between the position and mobility of atlas and cervicogenic headaches exists. Methods: 60 Subjects were recruited. Self-reported outcome measures, passive neck flexion rotation test, upper limb tension test (ULTT), slump test, and straight leg raise test (SLR) were assessed. Results: There was a significant difference in atlanto-axial rotation to the right with p=0.025. There was no statistical significance in left rotation. There was no significant relationship between CGH, ULTT, slump and SLR with P>0.05. Atlas position was significantly related to CGH with P<0.001, and position of the atlas was significantly related to atlanto-axial motion with p<0.001. Discussion: There is a direct relationship between the position and mobility of atlas and CGH. Fascial connections between structures could result in dural tension and should be considered when managing patients with CGH. The use of the ULTT, Slump test, and SLR test does not appear to be beneficial in identifying those with CGH.

Effect of a Flexor Digitorum Superficialis Hemitenodesis on Reducing Volar Plate Strains for Swan Neck Deformities

Hand ◽  
2021 ◽  
pp. 155894472110408
Author(s):  
Mohammad M. Haddara ◽  
Assaf Kadar ◽  
Louis M. Ferreira ◽  
Nina Suh
Keyword(s):  
Repeated Measures ◽  
Statistical Significance ◽  
Volar Plate ◽  
Flexor Digitorum Profundus ◽  
Flexor Digitorum Superficialis ◽  
Common Procedure ◽  
Motion Simulator ◽  
Significant Difference ◽  
Intact Condition ◽  
Flexor Digitorum

Background Flexor digitorum superficialis (FDS) hemitenodesis is a common procedure to treat swan neck deformity (SND). We hypothesize that this surgical technique is a biomechanically effective way to reduce strain in the volar plate at the proximal interphalangeal joint (PIPJ). Methods Fifteen digits from 5 cadaveric specimens were tested using a novel in vitro active finger motion simulator under 4 finger conditions: intact, SND, FDS hemitenodesis, and FDS hemitenodesis with distal interphalangeal (DIP) joint fusion. Tensile loads in FDS and flexor digitorum profundus (FDP) and joint ranges of motion were measured by electromagnetic tracking. In addition, strain gauges were inserted under the volar plate to measure strain during PIPJ hyperextension. Results were analyzed using 1-way repeated-measures analysis of variance tests. Results The SND condition increased volar plate strain by 176% ± 25% ( P < .001) compared with the intact condition. The FDS hemitenodesis repair relieved more than 50% of the SND strain, restoring it to within no statistical difference from intact. The DIP fusion further reduced strain with no further statistical significance. At full flexion, FDS and FDP tendon loads diverged as a function of the test condition ( P < .001). With the FDS hemitenodesis, the FDP load increased by 2.1 ± 1.5 N from the SND condition ( P < .001), whereas the FDS load decreased by 1.3 ± 1.3 N ( P = .012). Conclusion The FDS hemitenodesis repair restored strains to within 3.0 milli-strain of the intact condition with no significant difference. Application of DIP fusion did not further protect the PIPJ from increased hyperextension and further exacerbated the imbalance of flexor tendon loads.

Biomechanical analysis of stand-alone lumbar interbody cages versus 360° constructs: an in vitro and finite element investigation

2021 ◽  
pp. 1-9
Keyword(s):  
Interbody Fusion ◽  
Posterior Instrumentation ◽  
Axial Rotation ◽  
Posterior Fixation ◽  
Interbody Cage ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Lateral Interbody ◽  
Flexion And Extension

OBJECTIVE Low fusion rates and cage subsidence are limitations of lumbar fixation with stand-alone interbody cages. Various approaches to interbody cage placement exist, yet the need for supplemental posterior fixation is not clear from clinical studies. Therefore, as prospective clinical studies are lacking, a comparison of segmental kinematics, cage properties, and load sharing on vertebral endplates is needed. This laboratory investigation evaluates the mechanical stability and biomechanical properties of various interbody fixation techniques by performing cadaveric and finite element (FE) modeling studies. METHODS An in vitro experiment using 7 fresh-frozen human cadavers was designed to test intact spines with 1) stand-alone lateral interbody cage constructs (lateral interbody fusion, LIF) and 2) LIF supplemented with posterior pedicle screw-rod fixation (360° constructs). FE and kinematic data were used to validate a ligamentous FE model of the lumbopelvic spine. The validated model was then used to evaluate the stability of stand-alone LIF, transforaminal lumbar interbody fusion (TLIF), and anterior lumbar interbody fusion (ALIF) cages with and without supplemental posterior fixation at the L4–5 level. The FE models of intact and instrumented cases were subjected to a 400-N compressive preload followed by an 8-Nm bending moment to simulate physiological flexion, extension, bending, and axial rotation. Segmental kinematics and load sharing at the inferior endplate were compared. RESULTS The FE kinematic predictions were consistent with cadaveric data. The range of motion (ROM) in LIF was significantly lower than intact spines for both stand-alone and 360° constructs. The calculated reduction in motion with respect to intact spines for stand-alone constructs ranged from 43% to 66% for TLIF, 67%–82% for LIF, and 69%–86% for ALIF in flexion, extension, lateral bending, and axial rotation. In flexion and extension, the maximum reduction in motion was 70% for ALIF versus 81% in LIF for stand-alone cases. When supplemented with posterior fixation, the corresponding reduction in ROM was 76%–87% for TLIF, 86%–91% for LIF, and 90%–92% for ALIF. The addition of posterior instrumentation resulted in a significant reduction in peak stress at the superior endplate of the inferior segment in all scenarios. CONCLUSIONS Stand-alone ALIF and LIF cages are most effective in providing stability in lateral bending and axial rotation and less so in flexion and extension. Supplemental posterior instrumentation improves stability for all interbody techniques. Comparative clinical data are needed to further define the indications for stand-alone cages in lumbar fusion surgery.

scholarly journals Biomechanical Analysis of Capsular Repair Versus Arthrex TFCC Ulnar Tunnel Repair for Triangular Fibrocartilage Complex Tears

Hand ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 547-553 ◽  
Author(s):  
Jayson C. Johnson ◽  
Ferris M. Pfeiffer ◽  
Jill E. Jouret ◽  
David M. Brogan
Keyword(s):  
Statistical Significance ◽  
Triangular Fibrocartilage Complex ◽  
Optical Tracking ◽  
Biomechanical Analysis ◽  
Wrist Arthroscopy ◽  
Intact Specimen ◽  
Capsular Repair ◽  
Significant Difference ◽  
Triangular Fibrocartilage ◽  
Ulnar Tunnel

Background: This study compares the effectiveness of a peripheral capsular repair with a knotless arthroscopic transosseous ulnar tunnel repair (TR) in restoring distal radioulnar joint (DRUJ) stability and stiffness in the setting of a massive triangular fibrocartilage complex (TFCC) tear. Methods: Eight matched pairs of fresh-frozen cadaveric forearms were tested. Each forearm was tested in supination and pronation using 3-dimensional (3D) optical tracking devices prior to any intervention. Each specimen then underwent a diagnostic wrist arthroscopy and sectioning of the TFCC’s deep and superficial fibers. All specimens were then retested to assess instability secondary to the tear. The TFCC was repaired with either a peripheral capsular repair (CR) using three 2-0 polydioxanone sutures or a transosseous ulnar TR using a 2-0 FiberWire, and then retested (statistical significance; P < .05). Results: After TFCC arthroscopic sectioning, all specimens were unstable with a significant increase in translation and a significant decrease in stiffness. TFCC repair with TR resulted in displacement and stiffness similar to the native tissue. CR specimens were found to have significantly greater displacement and significantly decreased stiffness compared with the intact state. Conclusions: Arthroscopic sectioning of the TFCC resulted in DRUJ instability, as measured by stiffness and ulnar translation. TR effectively restored DRUJ stability and demonstrated no significant difference in postoperative stiffness or maximal displacement when compared with the intact specimen in pronation and supination. This study provides biomechanical evidence that an arthroscopic ulnar tunnel technique can restore stability to the DRUJ after a massive TFCC tear.

Comparison of Trunk Muscle Activity During Modified Side-Bridge Exercises and Traditional Side Bridge Exercise

2020 ◽  
Vol 29 (7) ◽  
pp. 963-969 ◽  
Author(s):  
Chi-Whan Choi ◽  
Jung-Wan Koo ◽  
Yeon-Gyu Jeong
Keyword(s):  
Analysis Of Variance ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Statistical Significance ◽  
Compressive Load ◽  
University Hospital ◽  
Healthy Men ◽  
Bonferroni Adjustment ◽  
Repeated Measures Analysis ◽  
Significant Difference

Context: The modified side-bridge exercise is designed for some special situations in which it is impossible to tolerate the compressive load on the side supported during the side bridge, such as in the older people with a hip or knee replacement and even in athletes with shoulder pain. Objectives: To examine the effects of 3 modified side-bridge exercises on the spinal stability muscles compared with traditional side-bridge (TSB) exercises for healthy men. Design: The effects of different exercises on the muscle activities of the external oblique (EO), internal oblique (IO), and quadratus lumborum (QL) during TSB exercise, both legs lift on side lying (BLLS), torso lift on a 45° bench while side lying (TLBS), and wall side bridge (WSB) were analyzed with the 1-way repeated-measures analysis of variance. Setting: This study was conducted in a university hospital laboratory. Participants: A total of 20 healthy men were recruited for this study. Interventions: The participants performed TSB, BLLS, TLBS, and WSB in a random order. Main Outcome Measures: Surface electromyography measured the muscle activity of the EO, IO, and QL. A 1-way repeated-measures analysis of variance assessed the statistical significance of the EO, IO, and QL muscle activity. When there was a significant difference, a Bonferroni adjustment was performed. Results: BLLS and TLBS showed similar effects to TSB in the EO, IO, and QL muscle activity, whereas WSB showed significantly less QL muscle activity than TSB (P < .05). Moreover, TLBS was significantly greater in the muscle activity of QL and EO than WSB (P < .05). Conclusion: BLLS and TLBS may be effective rehabilitation techniques to activate EO, IO, and QL in patients who are unable to perform TSB as spine stability exercises.

Effect of daily etidronate on the osteolysis of multiple myeloma.

1991 ◽  
Vol 9 (8) ◽  
pp. 1397-1402 ◽  
Author(s):  
A R Belch ◽  
D E Bergsagel ◽  
K Wilson ◽  
S O'Reilly ◽  
J Wilson ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Resorption ◽  
Repeated Measures ◽  
Bone Pain ◽  
Statistical Significance ◽  
Height Loss ◽  
Double Blind Study ◽  
Double Blind ◽  
Pathologic Fractures ◽  
Significant Difference

Progressive bone disease in multiple myeloma frequently leads to osteolysis, bone resorption, pathologic fractures, vertebral compression, and hypercalcemia. We conducted a double-blind study in 173 newly diagnosed multiple myeloma patients of etidronate disodium (EHDP), a diphosphonate compound that reduces bone resorption by inhibiting osteoclastic activity. The patients were randomly assigned to receive oral EHDP 5 mg/kg/d or placebo until death or discontinuation due to intolerance or refusal. The extent of vertebral deformity was measured by a vertebral index as well as height. The frequency of pathologic fractures, hypercalcemia, and bone pain was regularly assessed, as well as size and number of osteolytic lesions. All patients received melphalan and prednisone daily for 4 days every 4 weeks as the primary chemotherapy for their disease. Although the repeated measures analysis showed a significant height loss, there was no difference between treatment arms (P = .98). There was no significant difference in bone pain, episodes of hypercalcemia, or development of pathologic fractures. Patients on EHDP showed less deterioration in their vertebral index, but this difference only approached statistical significance (P = .07). We conclude that EHDP therapy used in this dosage schedule does not have a clinically significant impact in multiple myeloma.

scholarly journals Application of Wireless Contralateral Routing of Signal Technology in Unilateral Cochlear Implant Users with Bilateral Profound Hearing Loss

2019 ◽  
Vol 30 (07) ◽  
pp. 579-589 ◽  
Author(s):  
Hillary A. Snapp ◽  
Michael E. Hoffer ◽  
Anthony Spahr ◽  
Suhrud Rajguru
Keyword(s):  
Hearing Loss ◽  
Speech Perception ◽  
Cochlear Implant ◽  
Repeated Measures ◽  
Statistical Significance ◽  
Profound Hearing Loss ◽  
Speech In Noise ◽  
Bonferroni Adjustment ◽  
Significant Difference ◽  
Hearing Outcomes

AbstractThe aim of the study was to determine if contralateral routing of signal (CROS) technology results in improved hearing outcomes in unilateral cochlear implant (CI) patients and provides similar gains in speech perception in noise to traditional monaural listeners (MLs).The study is a prospective, within-subject repeated-measures experiment.Adult, English-speaking patients with bilateral severe–profound sensorineural hearing loss using an Advanced Bionics CI (n = 12) in one ear were enrolled for the study.Hearing performance in the monaural listening condition (CI only) was compared with the CROS-aided (unilateral CI + CROS) condition. Participants were tested for speech-in-noise performance using the Bamford-Kowal-Bench Speech-in-Noise™ test materials in the speech front/noise front (0 degrees/0 degrees azimuth), speech front/noise back (0 degrees/180 degrees azimuth), speech deaf ear/noise monaural ear (90 degrees/270 degrees azimuth), and speech monaural ear/noise deaf ear (90 degrees/270 degrees azimuth) configurations. Localization error was assessed using three custom stimuli consisting of 1/3 octave narrowband noises centered at 500 and 4000 Hz and a broadband speech stimulus. Localization stimuli were presented at random in the front hemifield by 19 speakers spatially separated by 10 degrees. Outcomes were compared with a previously described group of traditional MLs in the CROS-aided condition (normal hearing ear + CROS).All participants were tested acutely with no adaptation to the CROS device. Statistical analyses were performed using Wilcoxon signed rank tests for nonparametric data and paired sample. Statistical significance was set to p < 0.00625 after Bonferroni adjustment for eight tests.Significant benefit was observed from unaided to the CI + CROS–aided condition for listening in noise across most listening conditions with the greatest benefit observed in the speech deaf ear/noise monaural ear (90 degrees/270 degrees azimuth) condition (p < 0.0005). When compared with traditional MLs, no significant difference in decibel gain from the unaided to CROS-aided conditions was observed between participant groups. There was no improvement in localization ability in the CROS-aided condition for either participant group and no significant difference in performance between traditional MLs and unilateral CI listeners.These findings support that unilateral CI users are capable of achieving similar gains in speech perception to that of traditional MLs with wireless CROS. These results indicate that the use of wireless CROS stimulation in unilateral CI recipients provides increased benefit and an additional rehabilitative option for this population when bilateral implantation is not possible. The results suggest that noninvasive CROS solutions can successfully rehabilitate certain monaural listening deficits, provide improved hearing outcomes, and expand the reach of treatment in this population.

Sign in / Sign up

Export Citation Format

Share Document