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Biomedical subjects

D E Harrison

Publications and source records attributed to D E Harrison.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sitting biomechanics, part II: optimal car driver's seat and optimal driver's spinal model.

BACKGROUND: Driving has been associated with signs and symptoms caused by vibrations. Sitting causes the pelvis to rotate backwards and the lumbar lordosis to reduce. Lumbar support and armrests reduce disc pressure and electromyographically recorded values. However, the ideal driver's seat and an optimal seated spinal model have not been described. OBJECTIVE: To determine an optimal automobile seat and an ideal spinal model of a driver. DATA SOURCES: Information was obtained from peer-reviewed scientific journals and texts, automotive engineering reports, and the National Library of Medicine. CONCLUSION: Driving predisposes vehicle operators to low-back pain and degeneration. The optimal seat would have an adjustable seat back incline of 100 degrees from horizontal, a changeable depth of seat back to front edge of seat bottom, adjustable height, an adjustable seat bottom incline, firm (dense) foam in the seat bottom cushion, horizontally and vertically adjustable lumbar support, adjustable bilateral arm rests, adjustable head restraint with lordosis pad, seat shock absorbers to dampen frequencies in the 1 to 20 Hz range, and linear front-back travel of the seat enabling drivers of all sizes to reach the pedals. The lumbar support should be pulsating in depth to reduce static load. The seat back should be damped to reduce rebounding of the torso in rear-end impacts. The optimal driver's spinal model would be the average Harrison model in a 10 degrees posterior inclining seat back angle.

Automobile Driving↗
PubMed1999

A review of biomechanics of the central nervous system--Part I: spinal canal deformations resulting from changes in posture.

OBJECTIVE: To discuss how the spinal cord deforms as a result of changes in posture or biomechanical alterations of the spine. DATA COLLECTION: A hand search of available reference texts and a computer search of literature from the Index Medicus sources were collected, with special emphasis placed on spinal canal changes caused by various postural rotations and translations of the skull, thorax, and pelvis. RESULTS: All spinal postures will deform the spinal canal. Flexion causes a small increase in canal diameter and volume as the vertebral lamina are separated. Extension causes a small decrease in canal diameter and volume as the vertebral lamina are approximated. Lateral bending and axial rotation cause insignificant changes in spinal canal diameter and volume in cases without stenosis. CONCLUSIONS: Rotations of the global postural components, head, thoracic cage, and pelvis cause changes in the diameter of the spinal canal and intervertebral foramen. These changes are generally a reduction of less than 1.5 mm in extension, compared with a small increase in flexion of approximately 1 mm. These small changes do not account for the clinical observation of patients having increased neurologic signs and symptoms in flexion.

Biomechanical Phenomena↗
PubMed1999

Chiropractic biophysics digitized radiographic mensuration analysis of the anteroposterior lumbopelvic view: a reliability study.

OBJECTIVE: To investigate the reliability of a radiographic measurement procedure that uses a computer and sonic digitizer to determine projected spinal displacements from an ideal normal position. DESIGN: A blind, repeated-measure design was used. Anteroposterior lumbopelvic radiographs were presented to each of 3 examiners in random order. Each film was digitized, and the films were randomized for a second run. SETTING: Private, primary-care chiropractic clinic. MAIN OUTCOME MEASURES: The angle of the sacral base in comparison to a true horizontal line (horizontal base angle), lumbodorsal angle, lumbosacral angle, and the thoracic translational displacement from true vertical determined as the perpendicular distance from the center of T12 to a vertical axis line drawn from the center of the S1 spinous process cephalad and parallel to the lateral edge of the x-ray film. RESULTS: Intraexaminer reliability for the (a) horizontal base angle was .72 to .94, with confidence intervals included in the range of .52 to .97; (b) lumbodorsal angle was .90 to .96, with confidence intervals in the range of .82 to .98; (c) lumbosacral angle was .84 to .96, with confidence intervals in the range of .72 to .98, and (d) thoracic translational displacement from vertical was .95 to.97, with confidence intervals included in the range of .91 to .99. Interexaminer reliability for the three examiners ranged from .71 to .97. CONCLUSIONS: Measures similar to those described in this study are commonly used to measure and categorize spinal displacements from true vertical alignment (ie, scoliosis measurements). Most patient assessment methods used in chiropractic have poor or unknown reliability. The one possible exception to this rule is spinal displacement analysis performed on radiographs. In chiropractic, intraclass correlation coefficients values greater than .70 are considered accurate enough for use in clinical and research applications. The measures tested here would fit within these guidelines of reliability. Establishing reliability is an important first step in evaluating these measures so that future studies of validity may be undertaken.

Analysis of Variance↗
PubMed1999

A review of biomechanics of the central nervous system--part II: spinal cord strains from postural loads.

OBJECTIVE: To review spinal cord strains arising from postural loads. DATA COLLECTION: A hand search of available reference texts and a computer search of literature from the Indexed Medicus sources were collected, with special emphasis placed on spinal cord strains caused by various postural rotations and translations of the skull, thorax, and pelvis RESULTS: All spinal postures will deform the neural elements within the spinal canal. Flexion causes the largest canal length changes and, hence, the largest nervous system deformations. Neural tissue strains depend on the spinal level, the spinal movement generated, and the sequence of movements when more than one spinal area is moved. CONCLUSIONS: Rotations of the global postural components (head, thoracic cage, pelvis, and legs) cause stresses and strains in the central nervous system and peripheral nervous system. Translations of the skull, thorax, and pelvis, as well as combined postural loads, need to be studied for their effects on the spinal canal and neural tissue deformations. Flexion of any part of the spinal column may generate axial tension in the entire cord and nerve roots. Slight extension is the preferred position of the spine as far as reducing the magnitude of mechanical stresses and strains in the central nervous system is concerned.

Animals↗
PubMed1999

Correlation and quantification of projected 2-dimensional radiographic images with actual 3-dimensional Y-axis vertebral rotations.

BACKGROUND: Historically, measurement of 2-dimensional (2-D) radiographic images on the anteroposterior radiograph has been made to assess 3-dimensional (3-D) y-axis vertebral rotations. OBJECTIVES: To correlate and quantify measurements of the projected 2-D radiographic image with the degree of 3-D y-axis rotation. STUDY DESIGN: A computer model was positioned in a simulated x-ray beam. Points of model contact with the simulated beam were projected onto a line in the neutral position and the first 7 degrees of both positive and negative y-axis rotation using two different axes of rotation. A larger model, a shape-altered model, and a decreased source-object-distance model were also studied. RESULTS: 3-D y-axis rotation of vertebrae causes an off-center displacement of the 2-D projected lamina junction in relation to the projected vertebral body. The magnitude of displacement increases with increasing degrees of rotation. In our model, no clinically significant difference was found in the amount of the projected off-center displacement of the lamina junction between either of our two chosen axes of rotation. However, significant differences in the projected offset were found between vertebrae with the same degree of rotation as a result of changes in vertebral shape, size, and positioning. The projected lamina junction off-centering at a given rotation is quantified for our model. CONCLUSION: Use of millimetric measurement of the projected lamina offset on the anteroposterior radiograph is an inaccurate method for the assessment of the degree of 3-D y-axis vertebral rotation.

Biomechanical Phenomena↗
PubMed1999

Low back pain and the lumbar intervertebral disk: clinical considerations for the doctor of chiropractic.

BACKGROUND: Low back pain exists in epidemic proportions in the United States. Studies that demonstrate innervation to the intervertebral disk provide evidence that may account for instances of discogenic low back pain encountered in general medical and chiropractic practice. Many patients and health care practitioners believe that intervertebral disk lesions require surgery as the only method of treatment that will result in satisfactory outcome. Surgery rates vary widely across geographic regions. Only one randomized prospective study exists that compares surgical and nonsurgical treatment; it demonstrated essentially equal outcomes in the long run. OBJECTIVE: To review specific aspects of the examination, history, imaging, and treatment of patients with suspected intervertebral disk lesions and to provide guidelines for conservative management, imaging, and relative and absolute indications for surgical referral. DATA SOURCES: Review articles, texts, and original articles from indexed refereed sources that discuss the lumbar intervertebral disk in regard to patient history, physical examination, imaging, treatment, and referral for surgery. RESULTS: Patients with low back pain who do not present with so-called red flags (fever, history of cancer, unexplained weight loss, urinary tract infection, intravenous drug use, saddle anesthesia, or prolonged use of corticosteroids) may be treated initially with conservative methods. Imaging studies are helpful in determining the patient's diagnosis, and computed tomography, magnetic resonance imaging, or other special imaging studies should be ordered judiciously. The only prospective, randomized study of conservative versus surgical management of herniated lumbar intervertebral disk lesions indicates both methods provide adequate outcome in the long run. Little consensus exists on the best method of management for patients with intervertebral disk lesions without absolute indications for surgery. CONCLUSION: Patients should be screened for "red flags" to determine whether they are candidates for conservative treatment. Magnetic resonance imaging is perhaps the most practical imaging study for evaluation of lumbar disk lesions because it involves no use of ionizing radiation and because magnetic resonance imaging has other advantages over computed tomographic scanning such as excellent delineation of soft tissue structures, direct multiplanar imaging, and excellent characterization of medullary bone. Provocation computed tomography-diskography is an invasive procedure and should be reserved for patients with normal magnetic resonance imaging findings and continuing severe pain who have not been helped by conservative treatment attempts and for whom surgical intervention is contemplated. Both conservative and surgical interventions have been shown to be effective in the treatment of discogenic and radicular pain syndromes.

Chiropractic↗
PubMed1999

Lumbar coupling during lateral translations of the thoracic cage relative to a fixed pelvis.

OBJECTIVE: To determine lumbar coupling during lateral postural translations (lumbosacral list) of the thoracic cage relative to a fixed pelvis. DESIGN: Digitized measurements from anteroposterior lumbar radiographs of 17 volunteers were obtained in neutral, maximal left lateral translation and maximal right lateral translation posture of the thoracic cage compared to a fixed pelvis. Subjects were constrained with two sets of clamps at the lateral borders of the pelvis and lower ribs. BACKGROUND: Data. Clinically, lumbosacral list is a common posture. Range of motion and spinal coupling results have not been reported for the lumbosacral list movement. METHODS: Four vertebral body corners, mid narrow-waisted body margins, superior and inferior pedicle margins, and spinous-lamina junction of T12-L5 were digitized on 51 anterior-posterior lumbar radiographs. Using the orthogonal axes of positive x-direction to the left, vertical as positive y, and anterior as positive z, digitized points were used to measure projected segmental z-axis rotation, y-axis rotation, and segmental lateral translations of each vertebra. RESULTS: Using the displacement of T12, subjects could translate 35-70 mm left or right along the x-axis with an average of 53.2 mm to the left and 52.1 mm to the right. Using superior endplates to superior sacral base, lateral flexion was largest at L1 and decreased from L1 to L5, but the segmental rotation angles for lateral flexion were largest at L2-L3 (3.9 degrees ), L3-L4 (6.2 degrees ) and L4-L5 (5.7 degrees ) and were in the same direction as the main motion translation. The relative z-axis rotation of T12 was opposite to the direction of L1-L5. The coupled y-axis rotations were less than 1 degrees and coupled segmental lateral translations were averaging less than 1 mm. CONCLUSIONS: Thoracic cage x-axis translations compared to a fixed pelvis are significant, between 35 and 70 mm. The z-axis lumbar coupled rotation was largest at L2-L3, L3-L4 and L4-L5 and to the same side of the main motion translation in L1-L5, but opposite the main motion direction for T12. All other movements were small, averaging less than 1 degrees or 1 mm. RELEVANCE: The clinically common posture of lateral translation of the thoracic cage (lumbosacral list) is often associated with disc herniation. Yet normal lumbar coupling patterns and total range of motion of this movement have not been established in the literature. Normal values for lumbar segmental coupling on anterior-posterior lumbo-pelvic radiographs during trunk list might be important for an analysis of segmental instability since segmental translations were determined to be 1 mm or less.

Adult↗
PubMed1999

Development and aging of primitive hematopoietic stem cells in BALB/cBy mice.

Evaluating the function of an individual hematopoietic stem cell (HSC) is a difficult and important problem. The functional ability per HSC, as well as the HSC concentration, was measured with minimal disruption to the cells in vivo using the new competitive dilution assay. Distribution of HSC into recipients was modeled based on Poisson probabilities. Predictions of donor contributions from models assuming different levels of donor HSC functional ability and concentration were compared to actual observations. The model with the least difference between predictions and observations was accepted. In BALB/ cBy (BALB) mice, models assuming equal functional ability of HSC from the same donor fit extremely well with actual observations, suggesting that all HSC are functionally homogeneous at any particular time point during development or aging. Relative HSC functional ability per cell declined during development, so that a fetal HSC had 1.6 to 3.0 times the functional ability of a young adult HSC. The decline continued with age, so that a young adult HSC had 1.6 to 2.0 times the functional ability of an old HSC. Concentrations of HSC that engrafted and functioned were similar among 16-day fetal liver cells and bone marrow cells (BMC) from 3-month and 25 to 28-month-old adult mice. They were either 10 or 4 HSC per million cells when tested in BALB or CByB6F1 recipients, respectively. All HSC were pluripotent and produced lymphoid and myeloid descendants proportionally (r = 0.80 to 0.98, p < 0.01). Fetal and young HSC in both types of recipients maintained clonal stability long term so that percentages of donor cells at 6 and 9 months were strongly correlated (r = 0.72 to 0.93, p < 0.01). Although HSC from aged donors in BALB recipients maintained clonal stability, HSC from the same aged donors failed to show clonal stability in CByB6F1 recipients, perhaps due to the less suitable host environment. All HSC from BALB mice seemed to have equal functional levels at a given stage of life and were gradually exhausted simultaneously through development and aging.

Aging↗
PubMed1999

Information needs and preference for information of women with breast cancer over a first course of radiation therapy.

The study assessed the information needs of women receiving a course of radiation therapy (RT) for breast cancer and the relationship between information needs and preference for information. Thirty-three women were interviewed during the first (T1), third (T2), and last week of RT (T3), and one month later (T4) using the Toronto Informational Needs Questionnaire--Breast Cancer and the Information Subscale of the Health Opinion Survey. Information need scores were high and did not differ significantly across time. Information need and preference for information were correlated only at T1. Findings indicate that women with breast cancer receiving RT have high information needs and preference for information may not be a meaningful indicator of their desire for information. Health care providers need to assess the women's information needs frequently and be prepared to offer on-going educational support.

Adult↗
PubMed1998

Can the sagittal lumbar curvature be closely approximated by an ellipse?

For the sagittal lumbar curvature, existing spinal models are based only on the anthropomorphic radiographic characteristics of one individual, or, at best, of only a few individuals. This raises questions of applicability of the modeling results to clinical situations. Because spinal coupling and loads on spinal tissues have been shown to be functions of the initial static posture, a rigorously derived neutral lumbar lordosis would be important for clinicians and spine researchers. This study presents modeling of the sagittal lumbar spine in the shape of an ellipse. Vertebral body and disc heights, derived from digitized lateral lumbar radiographs of 50 normal subjects, were used to create an ellipse along the posterior body margins from the inferior of T12 to the superior sacral base. Additional data to create an elliptical lumbar model were determined from a least-squares analysis of passing ellipses through the digitized posterior body points. This confirmed that an elliptical model closely fit the lumbar curvature with a least-squares error of 1.2 mm per digitized point. The elliptical model is approximately an 85 degrees portion of a quadrant. The semi-major and semi-minor axes, a and b, are parallel to the posterior body margin of T12 and parallel to the inferior body endplate of T12, respectively, with a semi-minor to semi-major radio of b/a=0.39. The elliptic model has a height-to-length ratio of H/L=0.963, where height is the vertical distance from inferior T12 to superior S1 and length is the arc length along George's line (along the posterior longitudinal ligament) from T12 to S1.

Adult↗
PubMed1998

Delayed immune aging in diet-restricted B6CBAT6 F1 mice is associated with preservation of naive T cells.

Age-related changes in peripheral blood, spleen, and thymus of ad libitum (AL)-fed and dietary restricted (DR) C57BL/6J x CBA/CaH-T6/J F1 (B6CBAT6 F1) mice at young (3 mo), middle (16 mo), and old (30 mo) ages were studied to define how dietary restriction retards immune aging. Dietary restriction at 25% AL intake level initiated at weaning significantly reduced the rates of age-related declines in peripheral blood T helper cells, naive T helper cells, and naive cytotoxic T lymphocytes (CTLs). As a result, concentrations of these cell types in old DR mice were equivalent to 161%, 176%, and 250% of those in old AL controls. Dietary restriction also abolished age-related splenomegaly and decreased total splenocyte numbers in old DR mice. Dietary restriction did not prevent age-related decline in thymus size, but preserved thymus cellularity in old mice. Old DR mice had twice as many total thymocytes and 2.6 times as many CD4+CD8+ immature thymocytes as old AL controls. The correlations between total immature thymocytes and concentrations of circulating naive T helper cells and naive CTLs increase with age and become significant in old mice. Thus, dietary restriction preserves immature T-cell precursors in the thymus during aging to maintain higher concentrations of circulating T helper and naive T cells in peripheral blood.

Aging↗
PubMed1998

Structural rehabilitation of the spine and posture: rationale for treatment beyond the resolution of symptoms.

OBJECTIVE: To provide a rationale for active chiropractic rehabilitative treatment that extends beyond the single goal of resolution of symptomatic complaints. DATA COLLECTION: A manual search of available reference texts and a search of MEDLINE were collected with an emphasis on tissue healing sequelae and the role of mechanical loading on this process. RESULTS: The reviewed material indicates that all tissue growth and repair is influenced by mechanical loading and body posture and is positively affected by body postures that normalize/minimize adverse mechanical stresses and strains. Altered alignment of the human frame may lead to poor healing of the body tissues and eventual pathological architectural changes may occur in muscle, ligament, bone and central nervous system. Minimization of altered postural/structural loading of the human frame may take longer than resolution, or maximal reduction, of offensive symptoms. By itself, a patient's perception of pain is not a valid indicator of health. CONCLUSION: Because mechanical loading of the neuromusculoskeletal tissues plays a vital role in influencing proper growth and repair, chiropractic rehabilitative care should focus on the normalization/minimization of aberrant stresses and strains acting on spinal tissues. Manipulation alone cannot restore body postures or improve an altered sagittal spinal curve. Therefore, postural chiropractic adjustments, active exercises and stretches, resting spinal blocking procedures, extension traction and ergonomic education are deemed necessary for maximal spinal rehabilitation. Chiropractic studies that demonstrate structural improvements are sorely lacking and needed. The use of passive treatment modalities as the sole means of chiropractic intervention for the management of patients suffering with neuromusculoskeletal dysfunction no longer has a place in modern chiropractic practice after the acute phase of healing has passed.

Biomechanical Phenomena↗
PubMed1998

Three-dimensional spinal coupling mechanics: Part I. A review of the literature.

OBJECTIVE: To determine the state of knowledge relative to three-dimensional spinal coupled motion and to check the validity of currently accepted two-dimensional coupling as taught in chiropractic. DATA COLLECTION: A hand search of available reference texts and a computer search of literature from Index Medicus were collected with an emphasis on three-dimensional studies of human spinal movements. RESULTS: Most postural movements result in complicated three-dimensional spinal coupling in six degrees of freedom. Previous spinal coupling results based upon two-dimensional radiographic studies are inadequate and inaccurate. It is important that chiropractic colleges and techniques use the three-dimensional spinal kinematics to update their curricula and advance chiropractic treatment procedures. CONCLUSION: 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. Postural rotations and translations, which are the main motions studied in spinal coupling research, and altered configurations of the normal sagittal plane curves are the cause of both normal and abnormal spinal coupling patterns in three dimensions. Chiropractic letter listings (such as PRS, ASRP, etc.) are outdated, incomplete, invalid representations of coupled segmental movements. Mechanical loading of the neuromusculoskeletal tissues plays a vital role in position, dynamics, proper growth, repair and symptoms. Future studies of spinal kinematics should study the postural translations of the skull and thorax for their associated coupling in three dimensions. Combined postural rotations and translations along with altered sagittal curvatures need to be studied for their associated coupling characteristics as well.

Biomechanical Phenomena↗
PubMed1998

Reliability of spinal displacement analysis of plain X-rays: a review of commonly accepted facts and fallacies with implications for chiropractic education and technique.

BACKGROUND: Current medical, biomechanical, and chiropractic literature indicates that X-ray line drawing analysis for spinal displacement is reliable, with high Interclass Correlation Coefficients (ICCs) found in most studies. Normal sagittal spinal curvatures are being accepted as important clinical outcomes of care; however, just the opposite is taught in many chiropractic college radiology courses. OBJECTIVE: To review the current literature on X-ray line drawing reliability and abnormal static lateral positions. DATA SOURCES: Searches were performed on Medline, Chiro-LARS, MANTIS, and CINAHL on X-ray reliability, normal spinal position, and sagittal spinal curvatures as clinical outcomes. RESULTS: X-ray line drawing analysis for spinal displacement was found to have high reliability with a majority of ICCs in the .8-.9 range. The reliability for determining X-ray pathology was found to be only fair to good by both medical doctors and chiropractors and by both chiropractic and medical radiologists, with a majority of ICCs in the range .40-.75. Muscle spasms, facet hyperplasia, short pedicles and patient positioning errors have not been shown to alter sagittal plane alignment. The sagittal spinal curves are desirable clinical outcomes of care in surgery, physical therapy, rehabilitation and chiropractic. These results contradict common claims found in the indexed literature. CONCLUSION: X-ray line drawing is reliable. Normal values for the sagittal spinal curvatures exist in the literature. The normal sagittal spinal curvatures are important clinical outcomes of care. Patient positioning and postural radiographs are highly reproducible. When these standardized procedures are used, the pre-to-post alignment changes are a result of treatment procedures applied. Chiropractic radiology education and publications should reflect the recent literature, provide more support for X-ray line drawing analyses and applications of line drawing analyses for measuring spinal displacement on plain radiographs.

Anthropometry↗
PubMed1998

The effects of x-axis vertebral translation on projected y-axis vertebral rotation.

BACKGROUND: Few studies have quantified the projection/distortion errors that occur in anteroposterior (AP) radiographs. OBJECTIVES: To quantify the projection/distortion errors on AP radiographs caused by lateral translation of the vertebrae. To demonstrate the effect of vertebral shape on projection errors. STUDY DESIGN: Three models of increasing complexity were constructed to document the distortion. Model 1 consisted of three metal pins embedded in a piece of metal tubing that was X-rayed in three positions. Model 2, a simple model of the X-ray beam mounted on a wooden platform, allowed for translation of a vertebral model in a simulated X-ray beam and the measurement of projected points of contact between the model and rays of the simulated beam. Model 3 is a computer simulation of the X-ray beam in which a vertebral model was translated laterally to varying locations. The projected points of contact between the simulated rays and the vertebral body margins and lamina junction were measured. Model 3 also showed that vertebral body shape has a large effect on the projected axial rotation. Two other simple models were created and discussed in relation to shape-dependent projection errors. RESULTS: X-axis translation results in projected y-axis rotation. Increasing magnitudes of x-axis vertebral translation results in increasing magnitudes of projected y-axis vertebral rotation. The projected rotation is also influenced by vertebral shape. CONCLUSION: We have shown that three-dimensional lateral translation projects as axial rotation on the AP radiograph. Projection error is largely influenced by the shape of the object and by the increasing obliquity of the rays of the X-ray beam. This would seemingly create confusion and invalidate spinal listings of vertebral position obtained from the AP radiographic image.

Axis, Cervical Vertebra↗
PubMed1998

Further analysis of the reliability of the posterior tangent lateral lumbar radiographic mensuration procedure: concurrent validity of computer-aided X-ray digitization.

OBJECTIVE: To investigate the reliability of a specific method of radiographic analysis of the geometric configuration of the lumbopelvic spine in the sagittal plane, and to investigate the concurrent validity of a computer-aided digitization procedure designed to replace the more tedious and time-consuming manual measurement process. DESIGN: A blind, repeated-measures design was used. The results of radiographic measures derived through the traditional manual marking method were compared with measures derived by computer-aided digitization of lateral lumbopelvic radiographs. SETTING: Private chiropractic clinic. MAIN OUTCOME MEASURES: Pearson's product-moment correlation coefficients, paired sample t tests and intraclass correlation co-efficients (ICC) were used to examine intraexaminer reliability, and repeated measures of analysis of variance were used to examine interexaminer reliability for relative rotation angles for T12-L1, L1-L2, L2-L3, L3-L4, L4-L5, L5-S1, overall lordosis measurement [absolute rotation angle (ARA)] from L1-L5 and Cobb angle of overall lordosis measured from the inferior surface of T12 to the superior surface of S1, Ferguson's sacral base angle to horizontal, angle of pelvic tilt (arcuate angle) to horizontal and anteroposterior thoracic translation (Sz) in millimeters. RESULTS: ICC estimates for intraexaminer reliability were in the range of 0.96-0.98 for the L1-L5 ARA, a range of 0.87-0.99 for the arcuate angle measurement, 0.83-0.94 for the Ferguson's angle measurement, 0.88-0.95 for the Cobb angle measurement from the inferior surface of T12 compared with the superior surface of S1 and 0.98-1.00 for the translation measurement of the lower thoracic spine to S1 (Sz). The intersegmental measurement's (T12-L1, L1-L2, L2-L3, L3-L4, L4-L5, L5-S1) correlations ranged from a low of 0.55 to a high of 0.97. Examination of these findings suggests that the reliability for the three doctors is acceptable with only the T12-L1 intersegmental measure falling below 0.70 for the least experienced examiner. Average ICC of interexaminer reliability for manual and computer-aided digitizing examiners were the following: 0.96 for the L1-L5 ARA; 0.84 for the arcuate angle measurement; 0.82 for the Ferguson's angle measurement; 0.88 for the Cobb angle measurement; 1.00 for the Sz translation measurement; and values of 0.65, 0.73, 0.74, 0.75, 0.89 and 0.81 for relative rotation angle measurements T12-L1, L1-L2, L2-L3, L3-L4, L4-L5 and L5-S1, respectively. CONCLUSION: The data tend to support the reliability of this method of radiographic analysis of the geometric configuration of the lumbopelvic spine as viewed on lateral lumbopelvic radiographs. The additional data presented here tend to support the concurrent validity of the computer-aided digitization method of analysis inasmuch as the measures determined by the digitizing examiners are essentially identical to those determined by the manual method plus or minus the average standard error of measure of each value.

Humans↗