Experimental measurements of vertebral motion under load.
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Adolescent↗
Biomedical subjects
D G Wilder
Publications and source records attributed to D G Wilder.
Mechanical changes in the knee after meniscectomy.
A compression testing machine was used to transmit increasing loads at various strain rates across twelve canine and twelve human cadaver knees. The specimens were originally evaluated with both menisci intact and the same tests were repeated with one meniscus removed and then with both menisci removed. This investigation showed that the menisci perform a load-transmitting and energy-absorbing function in the knee joint. The stress acting across the joint increased significantly after meniscectomy. The intact meniscus was deformed during compressive loading rather than being passively pushed away, thus demonstrating the presence of hoop stresses within the meniscus.
Animals↗
Inhibitory effect of less intense stimuli upon the increment threshold for a narrow test line.
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Humans↗
Biomechanical testing as an aid to decision making in low-back pain patients.
Frequently, the diagnosis of disease of the low back is a difficult matter due to the multitude of factors affecting the patient's symptoms. In this report an attempt is made to use biomechanical testing to objectify certain aspects of the diagnostic process. Our philosophy is that a biomechanical assessment is one of the disciplines that should be brought to bear on the low-back pain patient. A group of biomechanical tests has been developed by adding quantitative measurement techniques to certain standard clinical maneuvers: muscle testing, range of motion testing, and straight leg raising testing. Moire fringe topography is employed for studying posture. Results of application of these techniques to 117 patients and 10 controls indicate potential utility in the method for epidemiologic and clinical research.
Back Pain↗
Objective measurement of L4-5 instability. A case report.
Segmental instability as a consequence of disc degeneration is presented as an entity capable of producing low-back pain which responds to surgical stabilization with spinal fusion, and is illustrated with a case report. Data from lumbar radiographs were analyzed with a computer, and the position changes of the lumbar vertebrae were computed relative to the neutral positions of each. The results indicate that segmental instability is a complex disruption of intervertebral motion, consistent with the coupling behavior of the spine.
Adult↗
The relation between biomechanical and psychological factors in patients with low-back pain.
Behavioral factors are increasingly being recognized for their role in determining the course and outcome of low-back disorders. This paper examines the relation between behavioral variables, which include psychological symptoms and pain tolerance, and biomechanical variables. The majority of the 89 patients tested could be classified into two groups. One group was intolerant of pain and showed reduced spinal mobility, restricted straight leg raising, and altered flexor-extensor muscle balance. The other group was more tolerant of pain and did not show restriction of motion or muscle imbalance. Spinal mobility was also related to psychological symptoms. A model is proposed which points to a feedback between spinal motion and the patient's ability to cope with pain as one mechanism that determines return to a functional range of motion.
Adaptation, Psychological↗
Epidemiologic studies of low-back pain.
The records of 3920 patients (2068 females, 1852 males) entering a model family practice unit between 1975 and 1978 have been analyzed. Eleven percent of males and 9.5% of females reported an episode of low-back pain during that 3-year interval. The complaint of medically reported low-back pain was significantly related to occupational factors such as truck driving (p < 0.001), lifting, carrying, pulling, pushing, and twisting (P < 0.001 for all variables) as well as nondriving vibrational exposure (P < 0.001). Patients reporting low-back pain also reported more episodes of anxiety (P < 0.001) and depression (P < 0.001) and had more emotionally stressful occupations (P < 0.001). The mean number of pregnancies was greater in women with low-back pain (2.6) than in those without (1.6) (P < 0.001). The low-back pain sufferers were more likely to be cigarette smokers (P < 0.001), particularly when smoking was accompanied by a chronic cough (P < 0.001). This population is currently under prospective study to define the relevance of each of these risk factors to the complaint of low-back pain.
Adolescent↗
The functional topography of the sacroiliac joint.
This work analyzes the motion permitted by the topography of the sacroiliac joint surface. Gross contour profiles of the joint were recorded in the frontal and sagittal planes. Best-fit axes of rotation for each contour profile were obtained by statistical methods and were compared with those reported in the literature. There was considerable scatter of the locations of the most likely centers, or axes, of rotation in the frontal and sagittal planes. Were motion to occur about these axes, the articular surfaces would first separate by a distance sufficient to allow them to move over one another. Energy would be needed to separate the joint surfaces being pulled together by the surrounding ligaments. Thus, the sacroiliac joint may function as a shock- absorbing structure by virtue of energy absorbed in the ligamentous tissue.
Female↗
1980 Volvo award in clinical sciences. Assessment of patients with low-back pain by biplanar radiographic measurement of intervertebral motion.
Abnormalities of intervertebral joint motion including hypermobility, reduced mobility, torsional abnormality, and displacement of the center of rotation have been associated with degenerative change. However, measurement of these signs in plane X-ray films is handicapped by the three-dimensional motion and geometry of the spine. This study aimed to relate three-dimensional motion of the joints to their pathological state. We have used biplanar radiography to measure intervertebral motion during voluntary movements by patients with low back pain. Primary (or intentional) and coupled motions were measured by a refined technique, along with disc shear and facet joint motion. Abnormalities were found, especially in the "coupled" motions which were related to narrowed disc space, and to proximity to previous fusions. There was asymmetry of motion specific to joints with herniated nucleus pulposus.
Back Pain↗
Vibration and the human spine.
Vibrational effects have been found to be associated with increased frequency of low-back pain in various industries, and because of this the study herein reported was conducted to assess the physiologic response of the spinal system to sinusoidal vibrations. A device replicating industrial vibration was constructed and employed on healthy human volunteers to determine the stiffness, impedence, and resonant characteristics of the subjects. Three peaks of enhanced transmissibility corresponding to the resonant frequency of the spinal system were found. The greatest transmissibility of vibratory input occurs at the first resonant frequency (5Hz) where marked enhancement of vibrational input occurs as vibrations pass through the spinal system. A progressive stiffening of the system occurs in response to vibrational inputs of increasing frequency. The effects of posture, the Valsalva maneuver, and fatigue alter the normal response. Structures vibrated at the first resonant frequency have greater potential for damage.
Adolescent↗
Moiré fringe topography of the human body.
Moiré fringe topography is introduced as a technique for the quantification of musculoskeletal diseases. The apparatus described includes a glass grid, Polaroid camera, and a 1000-W light source. With accurately positioned subjects, this technique has application in the evaluation of scoliosis, lumbar spine disease, and tumor evaluation . By optimizing the optical principles, computer analysis is allowed, which offers further quantification of contour changes associated with these disease states.
Back Pain↗