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Mikhail J, Funabashi M, Sobczak S, Descarreaux M, Pagé I. Investigation of the factors influencing spinal manipulative therapy force transmission through the thorax: a cadaveric study. Chiropr Man Therap 2023; 31:24. [PMID: 37550682 PMCID: PMC10405484 DOI: 10.1186/s12998-023-00493-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/16/2023] [Indexed: 08/09/2023] Open
Abstract
BACKGROUND Spinal manipulative therapy (SMT) clinical effects are believed to be linked to its force-time profile characteristics. Previous studies have revealed that the force measured at the patient-table interface is most commonly greater than the one applied at the clinician-patient interface. The factors explaining this force amplification remains unclear. OBJECTIVE To determine the difference between the force applied to a cadaveric specimen's thoracic spine and the resulting force measured by a force-sensing table, as well as to evaluate the relationship between this difference and both the SMT force-time characteristics and the specimens' characteristics. METHODS Twenty-five SMTs with different force-time profiles were delivered by an apparatus at the T7 vertebra of nine human cadaveric specimens lying prone on a treatment table equipped with a force plate. The difference between the force applied by the apparatus and the resulting force measured by the force plate was calculated in absolute force (Fdiff) and as the percentage of the applied force (Fdiff%). Kinematics markers were inserted into T6 to T8 spinous and transverse processes to evaluate vertebral displacements during the SMT thrusts. Mixed-effects linear models were run to evaluate the variance in Fdiff and Fdiff% explained by SMT characteristics (peak force, thrust duration and force application rate), T6 to T8 relative and total displacements, and specimens' characteristics (BMI, height, weight, kyphosis angle, thoracic thickness). RESULTS Sixty percent of the trials showed lower force measured at the force plate than the one applied at T7. Fdiff¸ was significantly predicted (R2marginal = 0.54) by peak force, thrust duration, thoracic thickness and T6-T7 relative displacement in the z-axis (postero-anterior). Fdiff% was significantly predicted (R2marginal = 0.56) by force application rate, thoracic thickness and total T6 displacements. For both dependant variables, thoracic thickness showed the highest R2marginal out of all predictors. CONCLUSION Difference in force between the clinician-patient and the patient-table interfaces is influenced by SMT force-time characteristics and by thoracic thickness. How these differences in force are associated with vertebral displacements remains unclear. Although further studies are needed, clinicians should consider thorax thickness as a possible modulator of forces being transmitted through it during prone SMT procedures.
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Affiliation(s)
- Jérémie Mikhail
- Department of Chiropractic, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
- Research Group on Neuromusculoskeletal Disorders, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
| | - Martha Funabashi
- Department of Chiropractic, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
- Canadian Memorial Chiropractic College, 6100 Leslie St, North York, ON, M2H 3J1, Canada
| | - Stéphane Sobczak
- Research Group on Neuromusculoskeletal Disorders, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
- Department of Anatomy, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
- Research Chair in Functional Anatomy, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, QC, G8Z 4M3, Trois-Rivières, Canada
| | - Martin Descarreaux
- Research Group on Neuromusculoskeletal Disorders, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
- Department of Human Kinetics, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada
| | - Isabelle Pagé
- Department of Chiropractic, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada.
- Research Group on Neuromusculoskeletal Disorders, Université du Québec à Trois-Rivières, 3351 Boul. des Forges, Trois-Rivières, QC, G8Z 4M3, Canada.
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), Centre Intégré Universitaire de Santé et de Services Sociaux de la Capitale-Nationale (CIUSSS-CN), 525 Boul. Wilfrid-Hamel, Québec City, QC, G1M 2S8, Canada.
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Reed WR, Lima CR, Liebschner MAK, Hurt CP, Li P, Gudavalli MR. Measurement of Force and Intramuscular Pressure Changes Related to Thrust Spinal Manipulation in an In Vivo Animal Model. BIOLOGY 2022; 12:biology12010062. [PMID: 36671758 PMCID: PMC9855381 DOI: 10.3390/biology12010062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023]
Abstract
Current knowledge regarding biomechanical in vivo deep tissue measures related to spinal manipulation remain somewhat limited. More in vivo animal studies are needed to better understand the effects viscoelastic tissue properties (i.e., dampening) have on applied spinal manipulation forces. This new knowledge may eventually help to determine whether positive clinical outcomes are associated with particular force thresholds reaching superficial and/or deep spinal tissues. A computer-controlled feedback motor and a modified Activator V device with a dynamic load cell attached were used to deliver thrust spinal manipulations at various magnitudes to the L7 spinous process in deeply anesthetized animals. Miniature pressure catheters (Millar SPR-1000) were inserted unilaterally into superficial and deep multifidi muscles. Measurements of applied mechanical forces and superficial/deep multifidi intramuscular pressure changes were recorded during spinal manipulations delivered in vivo. Manipulative forces and net changes in intramuscular pressures reaching deep spinal tissues are greatly diminished by viscoelastic properties of in vivo tissues, which could have possible clinical safety and/or mechanistic implications.
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Affiliation(s)
- William R. Reed
- Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Correspondence:
| | - Carla R. Lima
- Rehabilitation Sciences Program, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | - Christopher P. Hurt
- Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Peng Li
- School of Nursing, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Maruti R. Gudavalli
- College of Chiropractic Medicine, Keiser University, West Palm Beach, FL 33411, USA
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In vivo measurement of intradiscal pressure changes related to thrust and non-thrust spinal manipulation in an animal model: a pilot study. Chiropr Man Therap 2022; 30:36. [PMID: 36068588 PMCID: PMC9446573 DOI: 10.1186/s12998-022-00445-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 08/01/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The intervertebral disc is a known back pain generator and is frequently the focus of spinal manipulative therapy evaluation and treatment. The majority of our current knowledge regarding intradiscal pressure (IDP) changes related to spinal manual therapy involves cadaveric studies with their inherent limitations. Additional in vivo animal models are needed to investigate intervertebral disc physiological and molecular mechanisms related to spinal manipulation and spinal mobilization treatment for low back disorders. METHODS Miniature pressure catheters (Millar SPR-1000) were inserted into either the L4-L5 or L5-L6 intervertebral disc of 3 deeply anesthetized adult cats (Oct 2012-May 2013). Changes in IDP were recorded during delivery of instrument-assisted spinal manipulation (Activator V® and Pulstar®) and motorized spinal flexion with/without manual spinous process contact. RESULTS Motorized flexion of 30° without spinous contact decreased IDP of the L4-L5 disc by ~ 2.9 kPa, while physical contact of the L4 spinous process decreased IDP an additional ~ 1.4 kPa. Motorized flexion of 25° with L5 physical contact in a separate animal decreased IDP of the L5-L6 disc by ~ 1.0 kPa. Pulstar® impulses (setting 1-3) increased IDP of L4-L5 and L5-L6 intervertebral discs by ~ 2.5 to 3.0 kPa. Activator V® (setting 1-4) impulses increased L4-L5 IDP to a similar degree. Net changes in IDP amplitudes remained fairly consistent across settings on both devices regardless of device setting suggesting that viscoelastic properties of in vivo spinal tissues greatly dampen superficially applied manipulative forces prior to reaching deep back structures such as the intervertebral disc. CONCLUSIONS This study marks the first time that feline in vivo changes in IDP have been reported using clinically available instrument-assisted spinal manipulation devices and/or spinal mobilization procedures. The results of this pilot study indicate that a feline model can be used to investigate IDP changes related to spinal manual therapy mechanisms as well as the diminution of these spinal manipulative forces due to viscoelastic properties of the surrounding spinal tissues. Additional investigation of IDP changes is warranted in this and/or other in vivo animal models to provide better insights into the physiological effects and mechanisms of spinal manual therapy at the intervertebral disc level.
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