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Biomedical subjects

D D Harrison

Publications and source records attributed to D D Harrison.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Chiropractic biophysics lateral cervical film analysis reliability.

OBJECTIVE: To determine the degree to which the geometric line drawings used in Chiropractic Biophysics Technique (CBP) on lateral cervical radiographs are reliable. DESIGN: A blind, delayed repeated measures design was used. Three examiners were presented radiographs in random order. All identifying marks were removed prior to each examiner's individual marking and measurement. Each examiner was blinded as to how the previous examiners marked and measured the radiographs. SETTING: Primary care private chiropractic clinic. PATIENTS PARTICIPANTS: Sixty-five subject films were provided from the patient records of a primary care private chiropractic clinic. The 65 radiographs qualified for inclusion in the study based on two criteria: C1 through C7 had to be clearly visible, and there had to be no identifying artifacts. MAIN OUTCOME MEASURES: Anterior head translation in millimeters, atlas plane to horizontal, Ruth Jackson's cervical stress lines, and five relative rotation angles for C2-C3, C3-C4, C4-C5, C5-C6, C6-C7. Inter- and intrareliability of the three examiners were statistically analyzed. RESULTS: Intraexaminer for a) C1 to horizontal reliability was .98-.99 with confidence intervals of .96-.99, b) absolute rotation angle from C2 to C7 reliability was .82-.95 with confidence intervals of .80-.99, c) anterior head translation [+Sz] reliability was .86-.99, with confidence intervals of .74-.99, d) relative rotation angle reliability ranges were (C2-C3) .99, and (C3-C4) .98-.99, (C4-C5) .88-.99, (C5-C6) .80-.99, and (C6-C7) .94-.98. Interexaminer reliabilities across examiners ranged from a) Winer:.89-.99 and b) Bartko: .72-.96. CONCLUSIONS: The reliabilities for intra- and interexaminer were all greater than .70, indicating that these measurements in CBP technique would be considered accurate enough to provide measurements for future clinical studies. The data indicated that the C6-C7 relative rotation angle was the least reliable measurement. This might be due to the very small angles found at this level.

Analysis of Variance↗
PubMedDate not supplied

A normal sagittal spinal configuration: a desirable clinical outcome.

OBJECTIVE: Traditional forms of chiropractic treatment methods have attempted to restore alignment of vertebrae to proposed "normal" positions. Although this approach has existed throughout chiropractic's 100-yr history, little has been written in the scientific literature in support of this approach. The objective of this review is to study further the rationale behind this approach and evaluate some of the mechanical, anatomical and physiological evidence upon which this chiropractic approach is based. STUDY SELECTION: Articles and studies were selected that discuss analysis of stress and strains in spinal tissues from gravitational loading and experimental deformation in human and animal models. Studies that included radiographic measurements and classifications of spinal configuration in the sagittal plane were reviewed for their relevance to the chiropractic concept of a typical, usual or normal spinal configuration against which to compare patients. CONCLUSION: The usual, typical or normal configuration of the cervical spine in the sagittal dimension is a lordosis with a range of 16.5-66 degrees when measured as tangent lines along the cervical curve of the posterior vertebral body margins of C2 and C7. An analysis of stresses and strains supports this claim, as do studies from the scientific literature that attempt to measure and classify average cervical configuration from large population bases. The use of normative data as a gauge against which to measure patients' structural health and as an outcome of the degree of success or failure of chiropractic interventions seem to be logical consequences of these findings.

Biomechanical Phenomena↗
PubMedDate not supplied

The sacroiliac joint: a review of anatomy and biomechanics with clinical implications.

OBJECTIVE: To examine the biomedical literature pertaining to the anatomy and biomechanics of the sacroiliac (SI) joint to update current concepts and treatment of SI joint dysfunctions. DATA COLLECTION: The biomedical literature was reviewed for articles containing information on the anatomy, mechanics, dysfunction and treatment of the SI articulation. Emphasis was placed on information published in the past decade. Textbooks and prior reviews were used to compare past and present information. RESULTS: The anatomy and mechanics of the SI joint and surrounding tissues are much more complex than taught in chiropractic colleges and technique systems. The motion of the joint is complex, involving simultaneous rotations of 3 degrees or less and translations of 2 mm or less in three dimensions. The axes of motion for the SI joint are not straightforward and are largely dependent upon the surface topography of the joints. Traditional chiropractic types of dysfunctions and displacements are oversimplified and specific SI joint adjustments have not been demonstrated to correct these displacements. The primary function of the integrated SI system is the transmission and dissipation of mechanical forces. History, physical examination and clinical diagnostic tests have failed to demonstrate predictive validity for true SI dysfunction. CONCLUSION: Treatment of the SI articulation is difficult and all known SI joint tests have questionable validity, with the exception of pain provocation tests. Clinical treatment should be aimed at improving the stability of the surrounding soft tissues and at reducing mechanical stresses and strains from poor posture or using orthotics to level the sacral base. Much more research is needed in the treatment of this area.

Biomechanical Phenomena↗
PubMedDate not supplied

Three-dimensional spinal coupling mechanics: Part II. Implications for chiropractic theories and practice.

OBJECTIVE: To compare the current knowledge of 3-D spinal mechanics and abnormal equilibrium states with chiropractic motion theories, chiropractic vertebral letter listing theories, and chiropractic technique theories. DATA COLLECTION: A manual search of available reference texts and a computer search of literature from Index Medicus were collected with an emphasis on 3-D studies of human spinal movements, segmental instability, Euler buckling of the spine, and chiropractic theories concerning vertebral movements. RESULTS: Previous spinal coupling results based upon two-dimensional radiographic studies are inadequate and inaccurate. Therefore, the validity of any chiropractic technique procedure, listing, motion analysis or adjusting style based on the two-dimensional radiograph and coupling studies must be questioned. We have identified four types of spinal subluxations (displacements) in the biomechanical literature: (a) posture main motion and associated segmental coupling, (b) Euler buckling viewed in the anteroposterior view, (c) snap through viewed in the lateral view and (d) segmental instability. CONCLUSIONS: Full three-dimensional investigations of spinal coupling patterns have shown that the vertebrae rotate and translate in all three axes and that previous theories of spinal coupling based upon two-dimensional studies are inaccurate and invalid. Previous chiropractic letter listings (e.g., PRI, PLS, etc.) of spinal displacements are inadequate and invalid. Only one of the four types of biomechanical displacements, segmental instability, is consistent with the traditional chiropractic theory of segmental spinal displacements; in general, this does not respond well to care. In general, vertebrae displacement must be viewed in the context of equilibrium configurations and one vertebra can not be displaced as an individual misalignment. Validity questions arise for any technique methods that use letter listings of displacement taken from motion palpation or two-dimensional radiographic analysis.

Biomechanical Phenomena↗