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Biomedical subjects

D M Spengler

Publications and source records attributed to D M Spengler.

At least 91 records · Page 5Linked to original sources
PubMed1980

Tensile fracture of cancellous bone.

Excised specimens of cancellous bone from human femora were subjected to compressive or tensile testing, and the resulting force-displacement curves were recorded. The relationships between bone strength and apparent density were similar for specimens tested in these two loading modes. The modulus of elasticity was also comparable for the tensile and compressive specimens. Specimens loaded in compression absorbed considerable energy after the initial fracture because of progressive impaction of the trabeculae. In the specimens loaded in tension, the fractured bone fragments separated and therefore absorbed little additional energy after the initial failure. The energy absorption capacity was thus significantly lower for the tensile specimens. The results of this study show that the primary difference in mechanical properties of cancellous bone tested in tension and compression is the energy absorption capacity. This finding suggests that tensile and avulsion fractures of cancellous bone observed clinically are associated with minimal energy absorption and therefore may be precipitated by relatively minor trauma.

Aged↗
PubMed1977

Application of the somatization factor of the MMPI-168 with low back pain patients.

The usefulness of the Somatization factor of the MMPI-168 with low back pain patients was examined in two separate studies. In study 1, 58 male veteran low back pain patients who had been divided into organic and mixed groups served as Ss. MMPI protocols were rescored for the five factors of Overall, Hunter, and Butcher (1973). The organic and mixed groups differed only on the Somatization factor. A cutting score of raw greater than or equal to 8 (T = 75) was determined to classify the sample correctly 74.5% of the time. In study 2, a second sample of 48 male veteran low back pain patients was divided into mixed, organic, and functional groups. The mixed group was subdivided further into a mixed-pain group who still were having pain and were seeking treatment and a mixed-relief group who were experiencing a reduction of pain and were returning to vocational activities. The functional and mixed-pain groups differed from the organic and mixed-relief groups on the Somatization and Depression factors. The cutting score determined in the study 1 correctly classified patients 83% of the time.

Adjustment Disorders↗
PubMed1977

Effect of beta-aminopropionitrile on bone mechanical properties.

In vivo beta-aminopropionitrile treatment caused significant changes in the mechanical properties of rat femora. In femora treated with beta-aminopropinitrile as compared with controls, there was a 44 per cent decrease in bone stiffness and a 47 per cent increase in bone deformation to failure. Bone ash was decreased 5 per cent in the treated group. It is likely that the decrease in bone ash was secondary to impaired intermolecular bone-collagen cross-linking, which is a well established consequence of treatment with beta-aminopropionitrile. Thus, beta-aminopropionitrile influences bone mechanical properties directly by impairing collagen cross-linking and indirectly by altering bone-matrix mineralization.

Aminopropionitrile↗
PubMedDate not supplied

Needle tract recurrences after closed biopsy for sarcoma: three cases and review of the literature.

BACKGROUND: Percutaneous closed needle biopsy of musculoskeletal neoplasms has gained in popularity. However, it remains controversial whether or not to resect the needle tract for fear of a local recurrence. A single published case report exists, noting the lone tract recurrence of an extremity skeletal osteosarcoma. METHODS: We report on three additional individuals who demonstrated that tract local recurrences may occur after a closed needle biopsy for nonosteosarcoma, nonextremity sarcomas. For perspective, the world literature is reviewed to identify tract recurrences for other malignancies and the results of needle biopsy in musculoskeletal neoplasms. RESULTS: Eighty-nine percent of needle tract local recurrences occur when carcinomas are subjected to biopsy, as reported in the literature. Forty-seven cases since 1950 are described representing essentially all tumor types. The nature of musculoskeletal neoplasms makes closed biopsy more difficult than for softer, more homogeneous, and easier to access neoplasms. CONCLUSIONS: Local recurrences of sarcoma may occur in closed needle biopsy tracts. Strong consideration should be given to open biopsy and tract resection.

Adult↗
PubMedDate not supplied

Multiplanar variations in the structural characteristics of cancellous bone.

A quantitative serial sectioning technique and a video-imaging procedure were used to obtain precise (20-microns voxels, in a 5 mm x 6 mm x 7 mm test volume) digital images of lumbar vertebral cancellous bone specimens. Conventional stereological image analyses were performed on this data to determine multiplanar (bulk) and surface planar variations in cancellous structural properties. Based upon an error analysis of subgroups of the complete serial planar images, our findings suggest that, for a plane resolution of 20 microns, sectioning at an increment < or = 100 microns along an axis is necessary to obtain accurate data of bulk structural properties of cancellous bone. Planar structural variations obtained from the serial sections of cancellous bone revealed a high degree of complexity and heterogeneity of the bone architecture. Bone area centers deviated from the section centroid and showed a helical variation along the primary or superior--inferior loading axis of samples. In comparison with the base planes (perpendicular to the superior-inferior axis), the lateral planes (parallel to the superior-inferior axis) of spine samples showed smaller mean values of structural indices and a more oriented structure. This structural anisotropy may be related to the functional mechanical anisotropy of the samples.

Adult↗
PubMedDate not supplied

Patient selection for lumbar discectomy. An objective approach.

A reproducible method is presented for selecting patients with low-back pain and sciatica for lumbar discectomy based on specific objective criteria in four categories: neurologic signs, sciatic tension signs, personality factors (MMPI scores), and lumbar myelography. Operative findings for 50 consecutive cases selected using this method revealed complete nucleus pulposus herniation in 43 cases. This contrasts with complete herniation in only 5 of 26 patients undergoing lumbar discectomy before the method was employed. This objective preoperative evaluation method reduced negative disc explorations and improved early surgical results. We recommend its use for patients being considered for elective lumbar discectomy.

Adolescent↗
PubMedDate not supplied

Low-back pain following multiple lumbar spine procedures. Failure of initial selection?

A retrospective review was made of 30 patients who had failed multiple traditional surgical procedures for low-back pain, sciatic pain, or both. The most common cause of the poor results appeared to be failure of initial selection, even though all patients appeared to meet traditional indications for operative intervention. Psychosocial problems (eg, drug abuse, alcoholism, marital discord, personality disturbances) were prevalent, but were not initially recognized. Thoughtful assessment of patients being considered for initial lumbar spine surgery, which includes objective psychological testing, may reduce the incidence of unsuccessful lumbar spine surgery.

Adult↗
PubMedDate not supplied

Rapid diaphyseal destruction. An unusual osseous manifestation of chronic granulocytic leukemia.

A patient with chronic granulocytic leukemia developed an unusual rapidly progressive mid-diaphyseal femoral lesion. Differentiating this myeloblastic lesion from other round cell tumors is most reliably done by a Wright-Giemsa stained touch preparation. Prompt palliative therapy with long bone stabilization permitted the patient to remain ambulatory until shortly before his death.

Adult↗
PubMedDate not supplied

The reversibility of disuse osteoporosis. Fluoride treatment and bone strength.

The biomechanical strength of femur of adult rats was tested after immobilization for 9 weeks and remobilization for 12 weeks of 1 hind leg. Some rats were also given a fluoride supplement of 200 ppm in the drinking water. As reflected in the ultimate torque and stiffness there was a decrease in bone strength due to immobilization. After 12 weeks of remobilization the stiffness remained lower than in normal animals of the same age. Fluoride supplement partially counteracted the effect of immobilization but after the remobilization period no positive effect of the fluoride supplement was observed. Remobilization per se is of much more significance than fluoride in restoration of bone strength.

Animals↗
PubMedDate not supplied

Lumbar discectomy. Results with limited disc excision and selective foraminotomy.

Fifty-four consecutive patients who underwent limited lumbar discectomy, based on specific objective criteria, were reviewed. Sixteen of these patients had a limited foraminotomy performed in addition to the limited discectomy. The postoperative results in these patients were good, and the fair to poor results appear to be related primarily to subjective factors, rather than to persistent objective impairment of neuromuscular function. These data do not support prior concern over an increased incidence of recurrent disc herniation with a limited discectomy. Lumbar discectomy performed with limited disc excision is a safe, effective, and reliable method for treating selected patients with herniated lumbar discs.

Evaluation Studies as Topic↗