Biomedical subjects

Donald D Harrison

Publications and source records attributed to Donald D Harrison.

At least 19 recordsLinked to original sources

PubMed2006

Validation of a computer analysis to determine 3-D rotations and translations of the rib cage in upright posture from three 2-D digital images.

Since thoracic cage posture affects lumbar spine coupling and loads on the spinal tissues and extremities, a scientific analysis of upright posture is needed. Common posture analyzers measure human posture as displacements from a plumb line, while the PosturePrint claims to measure head, rib cage, and pelvic postures as rotations and translations. In this study, it was decided to evaluate the validity of the PosturePrint Internet computer system's analysis of thoracic cage postures. In a university biomechanics laboratory, photographs of a mannequin thoracic cage were obtained in different postures on a stand in front of a digital camera. For each mannequin posture, three photographs were obtained (left lateral, right lateral, and AP). The mannequin thoracic cage was placed in 68 different single and combined postures (requiring 204 photographs) in five degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion-extension (Rx), and anterior-posterior translation (Tz). The PosturePrint system requires 13 reflective markers to be placed on the subject (mannequin) during photography and 16 additional "click-on" markers via computer mouse before a set of three photographs is analyzed by the PosturePrint computer system over the Internet. Errors were the differences between the positioned mannequin and the calculated positions from the computer system. Average absolute value errors were obtained by comparing the exact inputted posture to the PosturePrint computed values. Mean and standard deviation of computational errors for sagittal displacements of the thoracic cage were Rx=0.3+/-0.1 degrees , Tz=1.6+/-0.7 mm, and for frontal view displacements were Ry=1.2+/-1.0 degrees , Rz=0.6+/-0.4 degrees , and Tx=1.5+/-0.6 mm. The PosturePrint system is sufficiently accurate in measuring thoracic cage postures in five degrees of freedom on a mannequin indicating the need for a further study on human subjects.

Biomechanical Phenomena↗

PubMed2006

Radiographic pseudoscoliosis in healthy male subjects following voluntary lateral translation (side glide) of the thoracic spine.

OBJECTIVE: To determine projected Cobb angles associated with trunk list (side shift) posture, hypothesizing that the side shift "scoliotic" curvature would be similar to true scoliotic curvature in the early stages. DESIGN: Anteroposterior (AP) radiographs of volunteers in neutral, in left, and right lateral translations of the thoracic cage (trunk list) were digitized. SETTING: Computer laboratory. PARTICIPANTS: Fifteen healthy male volunteers. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Cobb and Risser-Ferguson angles determined from digitizing vertebral body corners from T12 to L5 on 51 AP lumbar radiographs. RESULTS: Using the horizontal displacement of T12 from S1, subjects could translate an average of 54.0 mm to the left and 52.5 mm to the right. The average digitized Cobb T12-L5 angle produced for the 30 translated postures was 16 degrees. Angles ranged from 2.6 degrees to 27.0 degrees. Risser-Ferguson angles averaged 10 degrees between T12 and L5. Statistical correlations were found between Cobb L1-5 and translation to the left (P=.015), Cobb T12-L5 and translation to the right (P=.024), Risser-Ferguson angle and translation to the left (P=.021), and the lumbosacral angle to the right and trunk translation to the right (P=.027). CONCLUSIONS: During lateral translation of the thorax (trunk list), coupled lumbar lateral flexion resulted in the appearance of a pseudoscoliosis on AP radiographs. For this trunk list posture, Cobb angles are considerable (16 degrees ) and increase as the magnitude of trunk translation increases. Differentiating true structural scoliosis from this pseudoscoliosis would be clinically important. The small coupled axial rotation in trunk list is in contrast to the considerable degree of axial rotation observed in structural idiopathic scoliosis.

Adult↗

PubMed2005

Spinal manipulation force and duration affect vertebral movement and neuromuscular responses.

BACKGROUND: Previous study in human subjects has documented biomechanical and neurophysiological responses to impulsive spinal manipulative thrusts, but very little is known about the neuromechanical effects of varying thrust force-time profiles. METHODS: Ten adolescent Merino sheep were anesthetized and posteroanterior mechanical thrusts were applied to the L3 spinous process using a computer-controlled, mechanical testing apparatus. Three variable pulse durations (10, 100, 200 ms, force = 80 N) and three variable force amplitudes (20, 40, 60 N, pulse duration = 100 ms) were examined for their effect on lumbar motion response (L3 displacement, L1, L2 acceleration) and normalized multifidus electromyographic response (L3, L4) using a repeated measures analysis of variance. FINDINGS: Increasing L3 posteroanterior force amplitude resulted in a fourfold linear increase in L3 posteroanterior vertebral displacement (p < 0.001) and adjacent segment (L1, L2) posteroanterior acceleration response (p < 0.001). L3 displacement was linearly correlated (p < 0.001) to the acceleration response over the 20-80 N force range (100 ms). At constant force, 10 ms thrusts resulted in nearly fivefold lower L3 displacements and significantly increased segmental (L2) acceleration responses compared to the 100 ms (19%, p = 0.005) and 200 ms (16%, p = 0.023) thrusts. Normalized electromyographic responses increased linearly with increasing force amplitude at higher amplitudes and were appreciably affected by mechanical excitation pulse duration. INTERPRETATION: Changes in the biomechanical and neuromuscular response of the ovine lumbar spine were observed in response to changes in the force-time characteristics of the spinal manipulative thrusts and may be an underlying mechanism in related clinical outcomes.

Animals↗

PubMed2005

Do sagittal plane anatomical variations (angulation) of the cervical facets and C2 odontoid affect the geometrical configuration of the cervical lordosis?

Anthropometric and statistical evaluation of measurements from digitization of 252 lateral cervical radiographs were used to investigate any correlation between radiographic measurements of cervical lordosis with sagittal plane facet angulation, articular pillar height, and inclination of the C2 odontoid with respect to the body of C2. Some researchers have hypothesized that facet and odontoid architecture variations can cause a reduction in cervical lordosis. To evaluate this hypothesis, the posterior aspect of the C2 dens, vertebral body corners, and superior and inferior facet surfaces of C2-C7 were digitized on 252 lateral cervical X-rays to calculate global angle, segmental angles, dens angle, facet angles, and facet height. No correlation between facet angle, articular pillar height, and cervical curve was found. Similarly, no correlation between the sagittal angle of the dens and any angle of cervical curvature was identified. There was correlation between the global ARA C2-C7 angle and the Cobb angles at C1-C7 (r = 0.71) and C2-C7 (r = 0.82). There was correlation between the global inclination of the atlas vertebral angle (APL) and the Cobb angle at C1-C7 (r = 0.66), Cobb angle at C2-C7 (r = 0.39), ARA C2-C7 (r = 0.42), and anterior translation of C2 compared to C7 (r = -0.46). Because no correlation between cervical facet and odontoid architecture and any segmental or global angle of cervical lordosis was found, conservative and surgical rehabilitative techniques aimed at the reduction of sagittal cervical deformities do not need to account for a patient's architecture of the cervical facets nor odontoid.

Adult↗

PubMed2005

Sagittal skin contour of the cervical spine: interexaminer and intraexaminer reliability of the flexicurve instrument.

OBJECTIVES: To evaluate reliability of a simple instrument, the flexicurve, in determining cervical sagittal skin contour. METHODS: This study obtained repeated random measurements involving 3 investigators and 30 subjects once per day over a 2-day trial period. Thirty normal subjects were examined for cervical spine skin contour twice by 3 separate investigators with a 1-day delay. With subjects in a neutral standing position, investigators placed the flexicurve on the posterior portion of the subject's neck from the external occipital protuberance to the vertebral prominens and traced the flexicurve shape onto paper. The tracings were divided into 6 equal arcs and digitized. Statistical computation was performed on the depth at 5 points, arc angle, and arc radius of curvature. Interexaminer and intraexaminer correlation coefficients (ICCs) were calculated to determine reliability. RESULTS: All interexaminer correlation coefficients were in the poor range (<0.40). For the arc radius, arc angle, depth at top one third, and depth at bottom two thirds, the intraexaminer correlation coefficients were in the poor range. For the 3 deepest depths, the intraexaminer correlation coefficients were in the fair range (0.4-0.50). CONCLUSION: The flexicurve showed marginal reliability with most (12/16) ICCs in the poor range (ICC <0.40) and 4 values in the fair range (0.4 < ICC < 0.5).

Adult↗

PubMed2005

Concurrent validity of flexicurve instrument measurements: sagittal skin contour of the cervical spine compared with lateral cervical radiographic measurements.

OBJECTIVES: The aim of this study was to compare flexicurve surface contour measurements of the cervical spine with radiographic measurements of cervical lordosis. METHODS: One examiner evaluated 96 patients with chronic neck pain in neutral posture using a flexible ruler, flexicurve, to measure sagittal contour of the skin over the cervical spine from the external occipital protuberance to the vertebra prominens. The flexicurve skin contour and neutral lateral radiographs were digitized and compared. The flexicurve and radiographs were categorized into height-length ratio, curve angle, curve depth, sum of depths, modified Ishihara's index, and inverse of radius. Mean values, SDs, mean differences, and limits of agreement were calculated. The differences between flexicurve measurement mean values and x-ray mean values were deemed significant if the lower limit of agreement exceeded 15% of the mean values for the x-ray measurements. RESULTS: For all variables, except the height-length ratio, the mean values of the flexicurve variables differed significantly from the corresponding mean values of the radiographic measurements. All Pearson correlation coefficients were in the very poor range (r < 0.15). CONCLUSION: The flexicurve sagittal skin contour measurement has poor concurrent validity compared with established radiographic measurements of the cervical lordosis. The flexicurve tracings always predicted lordosis, overestimated the lordosis compared with x-ray values, and cannot discriminate between radiographic lordosis, straightened, S curves, and kyphotic alignments of the cervical curve.

Adult↗

PubMed2004

Modeling of the sagittal cervical spine as a method to discriminate hypolordosis: results of elliptical and circular modeling in 72 asymptomatic subjects, 52 acute neck pain subjects, and 70 chronic neck pain subjects.

STUDY DESIGN: Computer analysis of digitized vertebral body corners on lateral cervical radiographs. OBJECTIVES: Using elliptical and circular modeling, the geometric shape of the path of the posterior bodies of C2-C7 was sought in normal, acute pain, and chronic pain subjects. To determine the least squares error per point for paths of geometric shapes, minor axis to major axis elliptical ratios (b/a), Cobb angles, sagittal balance of C2 above C7, and posterior tangent segmental and global angles. SUMMARY OF BACKGROUND DATA: When restricted to cervical lordotic configurations, normal, acute pain, and chronic pain subjects have not been compared for similarities or differences of these parameters. Conventional Cobb angles provide only a comparison of the endplates of the distal vertebrae, while geometric modeling provides the shape of the entire sagittal curves, the orientation of the spine, and segmental angles. METHODS: Radiographs of 72 normal subjects, 52 acute neck pain subjects, and 70 chronic neck pain subjects were digitized. For normal subjects, the inclusion criteria were no kyphotic cervical segments, no cranial-cervical symptoms, and less than +/- 10 mm horizontal displacement of C2 above C7. In pain subjects, inclusion criteria were no kyphotic cervical segments and less than 25 mm of horizontal displacement of C2 above C7. Measurements included segmental angles, global angles of lordosis (C1-C7 and C2-C7), height-to-length ratios, anterior weight bearing, and from modeling, circular center, and radius of curvature. RESULTS: In the normal group, a family of ellipses was found to closely approximate the posterior body margins of C2-C7 with a least squares error of less than 1 mm per vertebral body point. The only ellipse/circle found to include T1, with a least squares error of less than 1 mm, was a circle. Compared with the normal group, the pain group's mean radiographic angles were reduced and the radius of curvature was larger. For normal, acute, and chronic pain groups, the mean angles between posterior tangents on C2-C7 were 34.5 degrees, 28.6 degrees, and 22.0 degrees, C2-C7 Cobb angles were 26.8 degrees, 16.5 degrees, and 12.7 degrees, and radius of curvature were r = 132.8 mm, r = 179 mm, and r = 245.4 mm, respectively. CONCLUSIONS: The mean cervical lordosis for all groups could be closely modeled with a circle. Pain groups had hypolordosis and larger radiuses of curvature compared with the normal group. Circular modeling may be a valuable tool in the discrimination between normal lordosis and hypolordosis in normal and pain subjects.

Acute Disease↗

PubMed2004

A non-randomized clinical control trial of Harrison mirror image methods for correcting trunk list (lateral translations of the thoracic cage) in patients with chronic low back pain.

Spinal trunk list is a common occurrence in clinical practice, but few conservative methods of spinal rehabilitation have been reported. This study is a non-randomized clinical control trial of 63 consecutive retrospective subjects undergoing spinal rehabilitation and 23 prospective volunteer controls. All subjects presented with lateral thoracic-cage-translation posture (trunk list) and chronic low back pain. Initial and follow-up numerical pain rating scales (NRS) and AP lumbar radiographs were obtained after a mean of 11.5 weeks of care (average of 36 visits) for the treatment group and after a mean of 37.5 weeks for the control group. The radiographs were digitized and analyzed for a horizontal displacement of T12 from the second sacral tubercle, verticality of the lumbar spine at the sacral base, and any dextro/levo angle at mid-lumbar spine. Treatment subjects received the Harrison mirror image postural correction methods, which included an opposite trunk-list exercise and a new method of opposite trunk-list traction. Control subjects did not receive spinal rehabilitation therapy, but rather self-managed their back pain. For the treatment group, there were statistically significant improvements (approximately 50%) in all radiographic measurements and a decrease in pain intensity (NRS: 3.0 to 0.8). For the control group, no significant radiographic and NRS differences were found, except in trunk-list displacement of T12 to S1, worsened by 2.4 mm. Mirror image (opposite posture) postural corrective exercises and a new method of trunk-list traction resulted in 50% reduction in trunk list and were associated with nearly resolved pain intensity in this patient population. The findings warrant further study in the conservative treatment of chronic low back pain and spinal disorders.

Adult↗

PubMed2004

Anterior thoracic posture increases thoracolumbar disc loading.

In the absence of external forces, the largest contributor to intervertebral disc (IVD) loads and stresses is trunk muscular activity. The relationship between trunk posture, spine geometry, extensor muscle activity, and the loads and stresses acting on the IVD is not well understood. The objective of this study was to characterize changes in thoracolumbar disc loads and extensor muscle forces following anterior translation of the thoracic spine in the upright posture. Vertebral body geometries (C2 to S1) and the location of the femoral head and acetabulum centroids were obtained by digitizing lateral, full-spine radiographs of 13 men and five women volunteers without previous history of back pain. Two standing, lateral, full-spine radiographic views were obtained for each subject: a neutral-posture lateral radiograph and a radiograph during anterior translation of the thorax relative to the pelvis (while keeping T1 aligned over T12). Extensor muscle loads, and compression and shear stresses acting on the IVDs, were calculated for each posture using a previously validated biomechanical model. Comparing vertebral centroids for the neutral posture to the anterior posture, subjects were able to anterior translate +101.5 mm+/-33.0 mm (C7-hip axis), +81.5 mm+/-39.2 mm (C7-S1) (vertebral centroid of C7 compared with a vertical line through the vertebral centroid of S1), and +58.9 mm+/-19.1 mm (T12-S1). In the anterior translated posture, disc loads and stresses were significantly increased for all levels below T9. Increases in IVD compressive loads and shear loads, and the corresponding stresses, were most marked at the L5-S1 level and L3-L4 level, respectively. The extensor muscle loads required to maintain static equilibrium in the upright posture increased from 147.2 N (mean, neutral posture) to 667.1 N (mean, translated posture) at L5-S1. Compressive loads on the anterior and posterior L5-S1 disc nearly doubled in the anterior translated posture. Anterior translation of the thorax resulted in significantly increased loads and stresses acting on the thoracolumbar spine. This posture is common in lumbar spinal disorders and could contribute to lumbar disc pathologies, progression of L5-S1 spondylolisthesis deformities, and poor outcomes after lumbar spine surgery. In conclusion, anterior trunk translation in the standing subject increases extensor muscle activity and loads and stresses acting on the intervertebral disc in the lower thoracic and lumbar regions.

Biomechanical Phenomena↗

PubMed2004

Conservative methods for reducing lateral translation postures of the head: a nonrandomized clinical control trial.

Fifty-one retrospective, consecutive patients were compared to twenty-six prospective volunteer controls in a nonrandomized clinical control trial. Both groups had chronic neck pain and lateral head translation posture. For treatment subjects, beginning and follow-up pain scales and anteroposterior (AP) cervical radiographs were obtained after 12.8 weeks of care (average of 37 visits), while the duration was a mean of 12 months for control subjects. Digitized radiographs were analyzed for Risser-Ferguson angles and a horizontal translation distance of C2 from a vertical line through T3. For treatment, patients received the Harrison mirror-image postural methods, which include mechanically assisted manipulation, opposite head posture exercise, and opposite head translation posture traction. While no significant differences were found in the control group subjects' pain scores and AP radiographic measurements, statistically significant improvements were observed in the treatment group subjects' pain scores and lateral translation displacements of C2 compared to T3 (pretrial score: 13.7 mm, posttrial score: 6.8 mm) and in angle measurements.

Adult↗

PubMed2003

Do alterations in vertebral and disc dimensions affect an elliptical model of thoracic kyphosis?

STUDY DESIGN: Mathematical modeling, using least squares method, of thoracic kyphosis was constructed as digitized points from radiographs of 50 healthy patients. OBJECTIVE: To determine a simple geometric model of the thoracic kyphosis. SUMMARY OF BACKGROUND DATA: Thoracic kyphosis is an important parameter of health, but geometric models of kyphosis are rare. Few papers report vertebral body and disc height data. METHODS: Thoracic vertebral bodies were digitized on lateral radiographs of 50 healthy patients. The average path of the posterior vertebral body corners of T1 through T12 was modeled, in the least squares sense, with a portion of an ellipse. The best-fit ellipse was sectioned with different model partitions using four sets of vertebral body heights and disc heights. Segmental and global angles derived from these four models were compared with reported values in the literature. RESULTS: A 72 degrees portion of an ellipse, with a minor-to-major axis ratio of 0.69, can closely approximate the path of the posterior body corners from the inferior of T1 to the superior of T12. The posterior vertebral body heights and disc heights have an average ratio of approximately 5:1. Segmental angles from T3-T4 through T11-T12 for all four models are close to other reported values. The thoracic spine has a height-to-length ratio of approximately 0.96. CONCLUSIONS: Thoracic kyphosis from inferior-posterior T1 to superior-posterior T12 can be closely modeled (least squares error per point < 1 mm) with a 72 degrees piece of an ellipse with a minor-to-major axis ratio of 0.69. The major axis is parallel to the posterior body margin of T12, whereas the minor axis passes through the superior endplate of T12. Segmental angles derived from this elliptical modeling are in the range of values from healthy patients.

Humans↗

PubMed2003

Prediction of osteoporotic spinal deformity.

STUDY DESIGN: A biomechanical model was developed from full-spine lateral radiographs to predict osteoporotic spinal deformity in elderly subjects. OBJECTIVE: To investigate the biomechanics of age-related spinal deformity and concomitant height loss associated with vertebral osteoporosis. SUMMARY OF BACKGROUND DATA: Vertebral bone loss and disc degeneration associated with aging causes bone and disc structures to weaken and deform as a result of gravity and postural stresses. METHODS: An anatomically accurate sagittal-plane, upright-posture biomechanical model of the anterior spinal column (C2-S1) was created by digitizing lateral full-spine radiographs of 20 human subjects with a mean height of 176.8 cm and a mean body weight of 76.6 kg. Body weight loads were applied to the model, after which intervertebral disc and vertebral body forces and deformation were computed and the new spine geometry was calculated. The strength and stiffness of the vertebral bodies were reduced according to an osteopenic aging model and modulus reduction algorithm, respectively. RESULTS: The most osteopenic model (L3 F(ult) = 750 N) produced gross deformities of the spine, including anterior wedge-like fracture deformities at T7 and T8. In this model, increases in thoracic kyphosis and decreases in vertebral body height resulted in a 25.2% decrease in spinal height (C2-S1), an 8.6% decrease in total body height, and a 15.1-cm anterior translation of the C2 spine segment centroid. The resulting deformity qualitatively resembled deformities observed in elderly individuals with osteoporotic compression fractures. CONCLUSIONS: These predictions suggest that postural forces are responsible for initiation of osteoporotic spinal deformity in elderly subjects. Vertebral deformities are exacerbated by anterior translation of the upper spinal column, which increases compressive loads in the thoracolumbar region of the spine.

Age Factors↗

PubMed2003

Repeatability over time of posture, radiograph positioning, and radiograph line drawing: an analysis of six control groups.

BACKGROUND: There is debate concerning the repeatability of posture over time, radiograph positioning repeatability, and radiograph line drawing reliability. These ideas seem to negate the use of before-and-after spinal radiographic imaging to detect and correct vertebral subluxations. OBJECTIVE: To review the results of control groups in 6 clinical control trials with before-and-after radiographic measurements taken days, weeks, months, or years apart to accept or reject the hypothesis that radiographic analysis procedures are not repeatable, reliable, or reproducible. DATA SOURCES: Six published control groups from original data. Other data were obtained from searches on MEDLINE, CHIROLARS, MANTIS, and CINAHL on radiographic reliability, posture, and positioning. RESULTS: Comparison of initial and follow-up radiographic data for 6 control groups indicate that measured angles and distances between initial and follow-up radiograph measurements on lateral and anterior to posterior radiographs are not significantly different when utilizing Chiropractic Biophysics radiographic procedures. In 48 out of 50 measurements, the differences between initial and follow-up radiographs are less than 1.5 degrees and 2 mm. These measurements indicate that posture is repeatable, radiographic positioning is repeatable, and radiographic line drawing analysis for spinal displacement is highly reliable. The scientific literature on these topics also indicates the repeatability of posture, radiographic positioning, and radiographic line drawing. CONCLUSIONS: Posture, radiographic positioning, and radiographic line drawing are all very reliable/repeatable. When Chiropractic Biophysics standardized procedures are used, any pre-to-post alignment changes in treatment groups are a result of the treatment procedures applied. These results contradict common claims made by several researchers and clinicians in the indexed literature. Chiropractic radiologic education and publications should reflect the recent literature, provide more support for posture analysis, radiographic positioning, radiographic line drawing analyses, and applications of posture and radiographic procedures for measuring spinal displacement on plain radiographs.

Biomechanical Phenomena↗

PubMed2002

A new 3-point bending traction method for restoring cervical lordosis and cervical manipulation: a nonrandomized clinical controlled trial.

OBJECTIVE: To evaluate a new 3-point bending type of cervical traction. DESIGN: Nonrandomized controlled trial of prospective, consecutive patients compared with control subjects. Follow-up patient data were obtained at 3 and 15(1/2) months, and 8 1/10 months for controls. SETTING: Data were collected at a spine clinic in Nevada. PATIENTS: Volunteer subjects consisted of 30 patients and 24 controls. Subjects had cervicogenic pain (neck pain, headaches, arm pain, and/or numbness). Subjects were included if their Ruth Jackson radiographic stress lines measured less than 25 degrees but were excluded if they had suspected disk herniation or canal stenosis. All subjects completed the first follow-up examinations, and 25 of 30 patients completed the long-term follow-up examination. INTERVENTIONS: Spinal manipulation for pain and a new form of 3-point bending cervical traction to improve lordosis. Cervical manipulation was provided for the first 3 to 4 weeks of treatment. Traction treatment consisted of 3 to 5 sessions per week for 9 +/- 1 weeks. MAIN OUTCOMES MEASURES: Besides pain visual analog scale (VAS) ratings, pre- and posttreatment lateral cervical radiographs were analyzed. RESULTS: Control subjects reported no change in the pain VAS ratings and had no statistically significant change in segmental or global radiographic alignment. For the traction group, VAS ratings were 4.3 pretreatment and 1.6 posttreatment. Traction group radiographic measurements showed statistically significant improvements (P <.008 in all instances of statistical significance), including anterior head weight bearing (improved 6.2mm), Cobb angle at C2-7 (improved 12.1 degrees ), and angle between posterior tangents at C2-7 (improved 14.2 degrees ). For the treatment group, at 15(1/2)-month follow-up, only minimal loss of C2-7 lordosis (3.5 degrees ) was observed. CONCLUSIONS: Sagittal cervical traction with transverse load at midneck (2-way cervical traction) combined with cervical manipulation can improve cervical lordosis in 8 to 10 weeks as indicated by increases in segmental and global cervical alignment. Magnitude of lordosis at C2-7 remained stable at long-term follow-up.

Adult↗

PubMed2002

Changes in sagittal lumbar configuration with a new method of extension traction: nonrandomized clinical controlled trial.

OBJECTIVE: To determine if a new method of lumbar extension traction can increase lordosis in chronic low back pain (LBP) subjects with decreased lordosis. DESIGN: Nonrandomized controlled trial with follow-up at 3 months and 1(1/2) years. SETTING: Primary care spine clinic in Nevada. PATIENTS: Beginning in mid-1998, the first 48 consecutive patients, who met the inclusion criteria of chronic LBP with decreased lordosis and who completed the treatment program were matched for sex, age, height, weight, and pain scores to 30 control subjects with chronic LBP, who received no treatment. INTERVENTIONS: A new form of 3-point bending lumbar extension traction was provided in-office 3 to 4 times a week for 12+/-4 weeks. Per session, traction duration was started at 3 minutes and was increased to a maximum of 20 minutes. For short-term pain relief, torsion lumbar spinal manipulation was provided in the initial 3 weeks. MAIN OUTCOME MEASURES: Pain as measured on a visual analog scale (VAS) and standing lateral lumbar radiographic measurements. RESULTS: Pain scales and radiographic measurements did not change in the control subjects. In the traction group, VAS ratings decreased from mean +/- standard deviation of 4.4+/-1.9 pretreatment to 0.6+/-0.9 posttreatment (P<.001), and radiographic angles (except at T12-L1) showed statistically significant changes. Mean changes were 5.7 degrees at L4-5 (P<.001), 11.3 degrees between posterior tangents on L1 and L5 (P<.001), 9.1 degrees in Cobb angle at T12-S1 (P<.001), 4.6 degrees in pelvic tilt (P<.001), and 4.7 degrees in Ferguson's sacral base angle (P<.001). At long-term follow-up (17(1/2)mo), 34 of the 48 (71%) subjects returned. Improvements in lordosis were maintained in all 34. CONCLUSIONS: This new method of lumbar extension traction is the first nonsurgical rehabilitative procedure to show increases in lumbar lordosis in chronic LBP subjects with hypolordosis. The fact that there was no change in control subjects' lumbar lordosis indicates the stability of the lumbar lordosis and the repeatability of x-ray procedures. Because, on average, chronic LBP patients have hypolordosis, additional randomized trials should be performed to evaluate the clinical significance of restoration of the lumbar lordosis in chronic LBP subjects.

Adult↗

PubMed2002

Reliability and measurement error of the BioTonix video posture evaluation system--Part I: Inanimate objects.

OBJECTIVE: To investigate the reliability, concurrent validity, and error of a new video digitizing system for evaluating posture when applied to inanimate objects. DESIGN: Delayed repeated measures of digital images of inanimate objects. SETTING: University laboratory. METHODS: Digital video images of inanimate objects (5 parallelograms) of different sizes and shapes were obtained with the BioTonix postural evaluation system. Three examiners digitized video images of inanimate objects twice; the second data collection was 1 week after the first set. The objects were digitized with both high- and low-resolution settings of the video screen. The Tonix's measurements were statistically compared with the actual object dimensions. Statistical evaluations of reliability and validity were conducted. RESULTS: For distances, both intraclass and interclass correlation coefficients were very high, 0.99 for the estimate. The low- versus high-resolution settings were comparable for distances. For angles, on the low-resolution setting, both intraclass and interclass correlation coefficients were very high: 0.969 and 0.953. On the high-resolution setting, for angles, both intraclass and interclass coefficients were well above 0.99. The difference of the actual size and the means of the digitized measurements of the means were small: at most 1.5 degrees for angles and 3.3 mm for distances. The standard deviations were small, and the confidence intervals were narrow. CONCLUSIONS: Our results demonstrate that the BioTonix's video system has high degrees of reliability and validity. Thus this system would seem suitable for clinical use in the analysis of posture.

Biomedical Technology↗

PubMed2002

Further reliability analysis of the Harrison radiographic line-drawing methods: crossed ICCs for lateral posterior tangents and modified Risser-Ferguson method on AP views.

OBJECTIVE: To determine whether the newly derived interclass and intraclass correlation coefficients (ICCs)would overstate or understate the results from 2 previously published studies, which used better known ICCs that assume nested factors, and to determine mean absolute differences of observers' measurements for 3 previous studies. STUDY DESIGN: Retrospective analysis of data from 2 blind studies with repeated-measure design. Two newly derived ICCs, appropriate to situations with 3 random factors (patients, examiners, and occasions) that bear a crossed (as opposed to nested) interrelationship, were applied to data from an experiment with random crossed factors. MAIN OUTCOME MEASURES: Observer reliability is determined with ICCs, 95% CIs, and observer error analysis (mean absolute differences of observers' measurements) for angles and distances derived from Harrison's modified Risser-Ferguson line-drawing method on anteroposterior (AP) lumbar and AP cervical radiographic views. Observer error analysis for angles and distances derived from Harrison's posterior tangent method on lateral cervical views was also determined. RESULTS: The majority of ICCs for reliability of line drawing on both AP cervical and AP lumbar radiographs were in the high range; 13 of 16 ICCs were greater than 0.88. The other 3 ICC values (0.61, 0.76, 0.78) concerned determining the sacral base on AP lumbar views. The new ICCs underestimated observer reliability compared with previously published results (intraclass ICCs lower by 0.01-0.02 and interclass ICCs lower by 0.03-0.10). For an error analysis on data from both AP views, the mean absolute differences of observers' measurements were 1.1 degrees to 1.8 degrees for angles and 1.2 mm to 2.3 mm for distances. For the lateral cervical analysis, the observer error was in the interval 0.8 degrees to 3.2 degrees for angles and <1 mm for distances. CONCLUSIONS: The ICCs assuming random crossed factors understate reliability compared with previously published ICC results assuming nested factors. Reliability of the Harrison modified Risser-Ferguson method of line-drawing analysis on AP views is in the high range, with the majority of ICCs >0.88. For both the Harrison modified Risser-Ferguson method on AP views and posterior tangent method on lateral cervical views, the mean absolute differences of observers' measurements are small.

Cervical Vertebrae↗

PubMed2002

Can the thoracic kyphosis be modeled with a simple geometric shape? The results of circular and elliptical modeling in 80 asymptomatic patients.

Many Cobb measurements have been reported at various levels for the thoracic kyphosis, but geometric models of the shape of kyphosis are rare. Thoracic vertebral bodies were digitized on 80 normal lateral full-spine radiographs to obtain the mean thoracic kyphosis. Global and segmental angles were determined. Computer iteration processes passed geometric shapes through the posterior body coordinates of the mean thoracic kyphosis to determine the best fit model in the least squares sense. The kyphosis was closely modeled with ellipses. The T1 and T12 areas tended to be flatter in curvature when compared with T2-T11, indicating these are inflection points. Mean global angles were Cobb(T1-T12) = 44.2 degrees, Cobb(T2-T11) = 39.9 degrees, and Cobb(T3-T10) = 33.3 degrees. The T2-T11 kyphotic region was closely modeled with approximately a 70-degree portion of an ellipse, with minor axis to major axis ratios of 0.6 to 0.72, and with major axis parallel to the posterior body margin of T11.

Adult↗