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Biomedical subjects

D R Benson

Publications and source records attributed to D R Benson.

At least 91 records · Page 5Linked to original sources
PubMed1981

The spine and surgical treatment in osteogenesis imperfecta.

In the osteogenesis imperfecta patient, spinal deformity should be expected, particularly in the severely affected nonambulator with chest deformity. Curves develop early (age five to six) and generally progress rapidly. Early bracing, although somewhat effective, may well compress the soft osteoporotic rib cage without controlling the spinal curvature. The pulmonary compromise created by the scoliosis is compounded by the chest cage deformity secondary to bracing. In the patient with severe disease (thin bones and numerous fractures), posterior correction and fusion, with or without Harrington instrumentation, is the preferred approach. This should be done early as the osteoporotic bone does not tolerate the hook forces well; the correction is correspondingly limited. The use of methylmethacrylate bone cement around the hook provides redistribution of forces and more stable fixation. In the patient with mild disease (thick bones and few fractures) treatment should be similar to that of patients with idiopathic scoliosis. The chest cage should be carefully observed to avoid deformity from placement of the lateral or posterior pad.

Bone Cements↗
PubMed1980

Hydrogenase in actinorhizal root nodules and root nodule homogenates.

Hydrogenases were measured in intact actinorhizal root nodules and from disrupted nodules of Alnus glutinosa, Alnus rhombifolia, Alnus rubra, and Myrica pensylvanica. Whole nodules took up H2 in an O2-dependent reaction. Endophyte preparations oxidized H2 through the oxyhydrogen reaction, but rates were enhanced when hydrogen uptake was coupled to artificial electron acceptors. Oxygen inhibited artifical acceptor-dependent H2 uptake. The hydrogenase system from M. pensylvanica had a different pattern of coupling to various electron acceptors than the hydrogenase systems from the alders; only the bayberry system evolved H2 from reduced viologen dyes.

Actinomycetales↗
PubMed1978

Autosterilization in low-velocity bullets.

Following a previous study (1) in which contaminated low-velocity bullets were discharged into sterile gelatin blocks with resultant growth of organisms along projectile tracts, the authors fired bullets coated with 1 drop of Staph. aureus-contaminated medium and bullets under sterile conditions into sterilized sand. Each contaminated projectile and its gun barrel were culture positive after firing. Therefore bullets should not be ruled out as possible sources of infection.

Sterilization↗
PubMed1978

Quantitative microbiology of traumatic orthopedic wounds.

Quantitative bacterial and fungal cultures carried out on 116 speciments of tissue debrided from traumatic orthopedic wounds yielded 118 bacterial and 8 fungal isolates. The organisms obtained reflected primarily the resident flora of the skin.

Aerobiosis↗
PubMed1978

The spine in osteogenesis imperfecta.

A high incidence of spinal curvature, approaching 80 per cent in patients more than twelve years old, was found in a large series of patients with osteogenesis imperfecta. Curves showed early progression and a predictable pattern. In the age range between one and five years the incidence of scoliosis was 26 per cent; thereafter, it rose precipitously. The degree of curvature was greater in the older children. The Milwaukee brace was ineffective in the treatment of the scoliosis and the complications of its use were detrimental. In several patients it deformed the rib cage. It had little or no effect on the progression of the curve. The incidence and degree of curvature was related to the type of bone present. Patients with chest deformities and those who were not ambulatory seemed to have a predilection for scoliosis.

Bone and Bones↗
PubMed1977

Results of school screening for scoliosis in the San Juan Unified School District, Sacramento, California.

Annual routine school examination for scoliosis has been established in the San Juan Unified School District. Additionally, several parochial schools and other schools in the county or nearby towns have expressed interest in such a program. A rapid, effective method, taking no more than 30 seconds per child, has been used to detect spinal curvature. The program is beneficial for those identified with scoliosis, because early detection, followed by proper treatment, can prevent major surgery. The need for careful school nurse follow-up must be emphasized. A standing x-ray and evaluation by a qualified physician are imperative. If scoliosis is diagnosed, the school nurse can be a very effective contact in assisting the students by discussing exercise or brace care and by providing encouragement and general supportive help.

Adolescent↗
PubMed1977

Harrington rod distraction instrumentation: its effect on vertebral rotation and thoracic compensation.

The effects of Harrington rod distraction instrumentation on vertebral rotation and thoracic decompensation were investigated radiographically both pre- and post-operatively. A method for semiquantitatively evaluating thoracic decompensation is introduced to serve as an adjunct to the evaluation of spinal deformity. Although little derotation of the vertebrae occurs with lateral correction, thoracic decompensation should be significantly improved.

Adolescent↗
PubMed1976

Roentgenographic evaluation of vertebral rotation.

To examine the accuracy of vertebral rotation determinations made from roentgenographic pedicle-shadow offset measurements, roentgenograms were made of fifteen cadaver vertebrae with different sagittal and frontal inclinations and longitudinal axis rotations ranging from 15 degrees left to 45 degrees right. It was found that significant uncertainties arise when vertebral rotation is evaluated from measurements of pedicle-shadow offset: true and apparent offsets in a single vertebra differ markedly; vertebrae from different spines have different offsets for the same degree of rotation and the same inclinations; and changes in the sagittal and frontal inclinations of a single vertebra alter its offset in the same manner as changes in rotation. From these results, it seems unlikely that precise measurements of rotation changes in spines with mild or moderate scolioses, for example, can be made from anteroposterior roentgenograms.

Biomechanical Phenomena↗
PubMedDate not supplied

Missed cervical dissociation--recognizing and avoiding potential disaster.

Complete cervical disruptions are high-energy injuries often associated with polytrauma and spinal cord injury. Because these injuries disrupt all anterior and posterior stabilizers, they result in a highly unstable spine, and the injuries are usually apparent on screening radiographs. Patients with these injuries must be identified and protected during the multiple diagnostic and surgical procedures they may require during their initial evaluation and treatment. Emergency procedures must be carefully prioritized relative to other life-threatening injuries; formal evaluation of the cervical spine may be carried out before, after, or in stages around other urgently indicated procedures. Until the cervical spine is cleared, careful observation of precautions can avoid disasterous complications in even the most unstable situation. A case of complete cervical disruption in a neurologically intact, hemodynamically unstable patient is presented for discussion. For polytraumatized patients with cervical dissociation, combined anterior and posterior stabilization is the treatment of choice.

Cervical Vertebrae↗
PubMedDate not supplied

Segmental instrumentation for thoracic and thoracolumbar fractures: prospective analysis of construct survival and five-year follow-up.

BACKGROUND CONTEXT: Segmental instrumentation systems have replaced nonsegmental systems in all areas of spine surgery. Construct patterns for fracture stabilization have been adapted from deformity experience and from biomechanical studies using nonsegmental systems. Few studies have been completed to validate the use of these implants in trauma or to assess their relative strengths and weaknesses. PURPOSE: To substantiate the safety and efficacy of segmental spinal instrumentation used to treat patients with unstable spinal fractures and to identify successful construct strategies and potential pitfalls. STUDY DESIGN: A prospective, longitudinal single cohort study of patients treated with segmental instrumentation for fractures of the spine. Minimum 2-year follow-up. PATIENT SAMPLE: Seventy-five consecutive patients with unstable fractures of the thoracic, thoracolumbar and lumbar vertebrae, admitted to a level 1 trauma center. All patients sustained high-energy injuries: fifty-five (79%) were injured in motor vehicle accidents, 27 (38%) sustained two or more major additional injuries and 39 (56%) had neurological injuries. OUTCOME MEASURES: Perioperative morbidity and mortality, blood loss, surgical time; postoperative recovery, neurological recovery, complications, thromboembolic and pulmonary disease; long-term outcome measures of fusion, sagittal spinal alignment, construct survival, patient pain and function measures, and return to work and activity. METHODS: A longitudinal, prospective study of surgical outcome after segmental spinal instrumentation. Multifactorial assessment was carried out at prescribed intervals to a mean follow-up of 5 years (range, 2 to 8 years) from the time of surgery. Seventy patients were included in the final analysis. There were 17 thoracic, 36 thoracolumbar and 17 lumbar fractures. RESULTS: At 52 months mean follow-up, 57 of 62 patients (92%) had solid fusion with acceptable spinal alignment. Perioperative complications and mortality were less than expected, based on historical controls matched for injury severity. Rod and hook constructs had 97% good to excellent functional results, with no hardware complications. Six of 11 (55%) patients with short-segment pedicle instrumentation (SSPI) with no anterior column reconstruction had greater than 10 degrees of sagittal collapse during the fracture healing period. Twenty six of 36 neurologically injured patients (72%) experienced (mean) 1.5 Frankel grades recovery after decompression and stabilization. Residual neurological deficit determined return to work: 43 patients (70%) returned to work, 33 without restrictions, 10 with limitations. Five other patients (8%) were fit but unemployed. Fifteen percent experienced some form of hardware failure, but only three (5%) required revision. Hardware complications and fair to poor outcomes occurred after pedicle instrumentation without anterior reconstruction. Patients with anterior reconstruction had 100% construct survival, no sagittal deformity, and less pain. CONCLUSION: Segmental instrumentation allowed immediate mobilization of these severely injured patients, eliminating thromboembolic and pulmonary complications, and reducing overall morbidity and mortality. Segmental instrumentation produced a high rate of fusion with no rod breakage or hook failure. Pedicle screw constructs had a high rate of screw complications associated with anterior column insufficiency, but revision was not always necessary. Eighty percent of these severely injured patients were capable of returning to full-time employment, and 70% did so.

Accidents, Traffic↗
PubMedDate not supplied

Genetics of scoliosis in chickens.

The genetics of an inherited form of scoliosis in chickens was studied to estimate the number of genes involved, whether they are autosomal or sex-linked, their degree of dominance and penetrance, and the heritability of this trait in this population. Expression of scoliosis and in the progeny was analyzed by radiographs of birds 12 weeks of age or older. Crosses between an inbred line selected for scoliosis expression (incidence of scoliosis - 89 percent) and a highly inbred line displaying normal spinal development provided data for genetic analyses. The incidence of expression of scoliotic parent line implicates three major autosomal, recessive genes. The significantly higher incidence of severe scoliosis found in the homogametic male sex is ascribed to a sex-influenced, on the scoliosis trait rather than to sex-linkage. Variation of expression observed in the scoliotic line is attributed to incomplete penetrance of the major genes, additive effects of minor modifying genes, and primarily to environmental effects. Because of the similarities in the expression of this disease in chickens and humans, the inheritance pattern determined for chickens may provide useful insights into that operating for so-called adolescent idiopathic scoliosis in humans.

Animals↗
PubMedDate not supplied

HIV precautions for prevention in the workplace.

The concern over transmission of blood-borne disease from health care workers to patients has become a topic of increasing concern. The Human Immunodeficiency Virus (HIV) is one of these diseases. Mandatory HIV antibody testing of all patients and health care workers is currently under consideration with no solution immediately on the horizon. Orthopaedic health care workers are often involved in emergent care of trauma victims without the benefit of knowing the HIV status of these patients. Therefore, the only solution is to employ meticulous barrier techniques to prevent transmission of diseases such as HIV infection. Precautions for orthopaedic nurses are discussed in an effort to provide guidelines for prevention of transmission of disease.

Centers for Disease Control and Prevention, U.S.↗