Browsing by Author "Triano, John J."
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- ItemOpen AccessKinematics of the head and associated vertebral artery length changes during high-velocity, low-amplitude cervical spine manipulation(2022-06-01) Gorrell, Lindsay M.; Kuntze, Gregor; Ronsky, Janet L.; Carter, Ryan; Symons, Bruce; Triano, John J.; Herzog, WalterAbstract Background Cervical spine manipulation (CSM) is a frequently used treatment for neck pain. Despite its demonstrated efficacy, concerns regarding the potential of stretch damage to vertebral arteries (VA) during CSM remain. The purpose of this study was to quantify the angular displacements of the head relative to the sternum and the associated VA length changes during the thrust phase of CSM. Methods Rotation and lateral flexion CSM procedures were delivered bilaterally from C1 to C7 to three male cadaveric donors (Jan 2016–Dec 2019). For each CSM the force–time profile was recorded using a thin, flexible pressure pad (100–200 Hz), to determine the timing of the thrust. Three dimensional displacements of the head relative to the sternum were recorded using an eight-camera motion analysis system (120–240 Hz) and angular displacements of the head relative to the sternum were computed in Matlab. Positive kinematic values indicate flexion, left lateral flexion, and left rotation. Ipsilateral refers to the same side as the clinician's contact and contralateral, the opposite. Length changes of the VA were recorded using eight piezoelectric ultrasound crystals (260–557 Hz), inserted along the entire vessel. VA length changes were calculated as D = (L1 − L0)/L0, where L0 = length of the whole VA (sum of segmental lengths) or the V3 segment at CSM thrust onset; L1 = whole VA or V3 length at peak force during the CSM thrust. Results Irrespective of the type of CSM, the side or level of CSM application, angular displacements of the head and associated VA length changes during the thrust phase of CSM were small. VA length changes during the thrust phase were largest with ipsilateral rotation CSM (producing contralateral head rotation): [mean ± SD (range)] whole artery [1.3 ± 1.0 (− 0.4 to 3.3%)]; and V3 segment [2.6 ± 3.6 (− 0.4 to 11.6%)]. Conclusions Mean head angular displacements and VA length changes were small during CSM thrusts. Of the four different CSM measured, mean VA length changes were largest during rotation procedures. This suggests that if clinicians wish to limit VA length changes during the thrust phase of CSM, consideration should be given to the type of CSM used.
- ItemOpen AccessMusculoskeletal Biomechanical and Electromyographical Responses Associated with Spinal Manipulation(2020-12-11) Gorrell, Lindsay Mary; Herzog, Walter; Triano, John J.; Ronsky, Janet L.; Edwards, William BrentThe primary goal of this thesis was to systematically describe biomechanical and electromyographic (EMG) responses of the human musculoskeletal system associated with cervical and upper thoracic spinal manipulation (SM). The overarching hypotheses were that: i) greater three-dimensional (3D) movements of the head and neck would be associated with larger vertebral artery (VA) strains; and ii) SM applied with greater force and more quickly would result in larger EMG responses. In the first project, a basic science methodology was used to measure: i) 3D movements of the head and neck and associated VA strains during cervical SM applied to human cadaveric donors; and ii) the elongation required for mechanical failure of the VA. Pre-positioning of the head and neck resulted in the largest changes in angular kinematics and arterial strain, while small changes occurred during the thrust. There were correlations between angular displacements and VA strains during cervical SM, however these were variable in direction (positive vs. negative) and strength (negligible to high). Arterial strains during cervical SM did not exceed those required to produce tensile stretch; therefore, it is unlikely the procedures delivered in this study could result in mechanical disruption of a healthy vessel wall. In the second project, an applied methodology was used to investigate: i) reflexogenic effects of cervical and upper thoracic SM in asymptomatic and neck pain participants; and ii) the relationship between SM kinetics and EMG responses. In asymptomatic participants, cervical and upper thoracic SM was often associated with EMG responses. However, responses occurred less frequently in symptomatic participants, suggesting that the reduction in EMG responses may be associated with pain-induced reflex inhibitions. Further, when two thrusts were delivered to the same spinal segment, following one another in quick succession, the second thrust was delivered more forcefully and more quickly, resulting in greater peak EMG responses and shorter neuromuscular delays. Collectively, the data in this thesis demonstrate that high-velocity, low-amplitude (HVLA) cervical and upper thoracic SM causes biomechanical and EMG responses within the musculoskeletal system. Further, these studies provide important safety and mechanistic data on cervical and upper thoracic SM.