Search PubMed⌕ Search

Biomedical subjects

R D Fraser

Publications and source records attributed to R D Fraser.

At least 37 records · Page 2Linked to original sources
PubMed1996

Clinical practice guidelines. Particular reference to the management of pain in the lumbosacral spine.

Clinical practice guidelines and protocols are a seductive way of trying to improve the standard of clinical practice. If these are to be most effective, they must evaluate rigorously the evidence supporting a particular management strategy and make appropriate recommendations based on this information. This process needs to be objective, should engage and obtain endorsement from the disciplines that are involved in providing the care, and be accompanied by appropriate implementation strategies. Subsequently, the impact of these strategies should be measured. Existing guidelines for the management of lumbosacral pain largely conform to criteria for guidelines development. It can therefore be expected that they will benefit practitioners and the community.

Costs and Cost Analysis↗
PubMed1996

Chemonucleolysis.

Even with a history of controversy and troubling complications, chymopapain has endured the test of time to show 30 years of clinical success in the treatment of herniated nucleus pulposus. Strict attention to indications, contraindications, and technique ensures safety and efficacy of treatment. A trend to decreased dosage may result in less postinjection spasm. Between 1982-1991, 121 adverse events in 135,000 patients were reported to the Food and Drug Administration and investigated. Seven cases of fatal anaphylaxis, 24 infections, 32 bleeding problems, 32 neurologic events, and 15 miscellaneous occurrences were found. Overall mortality rate was 0.019%. All categories were of lesser incidence than complications with laminectomy. Long-term results show that improvement after chemonucleolysis is maintained, whereas the outcome after laminectomy is reported to deteriorate with time. Cost savings with chemonucleolysis over laminectomy are largely a matter of shorter hospitalization. A protocol for cervical chemonucleolysis is being developed in the United States after good results have been shown in Spain and France. Other enzymes continue under investigation, but chymopapain remains the standard to which they are compared.

Adult↗
PubMed1996

Remodeling of vertebral bone after outer anular injury in sheep.

STUDY DESIGN: This study uses semiautomated histoquantitative techniques to analyze subchondral bone architecture in adult merino sheep up to 2 years after outer anular cuts were created in lumbar discs. OBJECTIVES: To describe morphometric changes to the adjacent vertebral bone structure in the lumbar spine, and to discuss these in relation to the pathology of other spinal components SUMMARY OF BACKGROUND DATA: Disc degeneration has been observed in the sheep lumbar spine 4-6 months after surgery to the outer anulus, whereas biomechanical testing has shown earlier changes. METHODS: Lumber discs with adjacent subchondral trabecular bone were sectioned using standard histologic methods. An image-analyzing computer was used to measure morphometric indices of bone structure. RESULTS: Trabecular bone volume was elevated significantly by 2 months because of consolidation of existing trabeculae and formation of new elements. The changes were evident 2 years after surgery. CONCLUSION: Subchondral trabecular bone appears to be sensitive to changes in the disc after outer anular injury. There is evidence that these structural changes are influenced by changes in the biomechanical behavior of the incised disc.

Animals↗
PubMed1996

The molecular structure of reptilian keratin.

X-ray diffraction and electron microscope studies of hard keratins (e.g. claws, scales, feathers and hair) have shown that they all have a filamentous texture but that the molecular structure of the filaments in mammalian keratins is quite different from that in avian keratins. The framework of the filaments in mammalian keratin consists of two-strand coiled coils of alpha-helices whereas the framework in avian keratins is composed of beta-sheets. Reptilian hard keratins have not been studied in detail but the X-ray diffraction pattern is very similar to that obtained from avian hard keratins leading to the supposition that the framework of the filaments is also composed of beta-sheets. The present contribution describes an analysis of the sequence of a lizard claw protein using structural probes which reveal the origins of the common structural features of the filaments in avian and reptilian keratin.

Animals↗
PubMed1996

The influence of pregnancy on the development of degenerative spondylolisthesis.

Degenerative spondylolisthesis is most common at the L4/L5 level and in women. There are several possible reasons for its predilection at this site, but there is no satisfactory explanation for the predominance in women. We considered that pregnancy was a possible influence. We reviewed the records and radiographs of 949 women and 120 men aged 50 years and over who had attended a spinal surgeon for low back pain over a five-year period. We found that women who had borne children had a significantly higher incidence of degenerative spondylolisthesis than nulliparous women (28% v 16.7%; p=0.043). The men had a 7.5% incidence, significantly less than nulliparous women (p = 0.031). Our results suggest that pregnancy is an important factor in the aetiology of degenerative spondylolisthesis.

Female↗
PubMed1995

Interbody, posterior, and combined lumbar fusions.

STUDY DESIGN: This is a review article on the different approaches used to obtain fusion of the lumbar spine. OBJECTIVE: To describe certain conceptual and technical aspects related to the various fusion techniques that are used commonly for lumbar spine disorders and to discuss the expected clinical results. SUMMARY OF BACKGROUND DATA: There are differences of opinion among surgeons concerning the preferred method for lumbar spine fusion, whether done for deformity, disease, trauma, or degeneration. METHODS: A review of the literature combined with personal experience formed the basis of this article. RESULTS: At the present time, analysis of the literature does not indicate that one form of fusion is significantly better than another for degenerative conditions of the lumbar spine. There is recent evidence suggesting better outcomes (as distinct from subjective opinion alone) are obtained after anterior interbody fusion than after posterolateral fusion with internal fixation, despite a higher fusion rate in the latter group. There is evidence that suggests late spinal stenosis adjacent to a fusion is more likely to occur with posterior fusion procedures than with anterior fusion alone. CONCLUSIONS: Significant potential complications are associated with all techniques, particularly neurologic damage with posterior interbody fusion, and vascular injury with anterior interbody fusion. Spinal fusion procedures should only be done by surgeons with the necessary training and expertise.

Humans↗
PubMed1995

Bony and vascular anatomy of the normal cervical spine in the sheep.

STUDY DESIGN: This study analyzed the vascular and skeletal anatomy of the sheep cervical spine. It discusses the comparative anatomy of the cervical spine of sheep and humans. OBJECTIVES: To establish the suitability of the sheep model for studying the pathophysiology of traumatic and degenerative conditions of the cervical spine. SUMMARY OF BACKGROUND DATA: Many studies have attempted to evaluate the pathophysiology of spinal cord trauma, hypoxia, and variations in the local environment of the spinal cord using a variety of animal models. Few of the studies identified in an extensive literature review report or comment on the validity of these models regarding anatomy. METHODS: Techniques of macro- and micro-dissection and vascular casting with latex and methylmethacrylate were employed and the anatomy of sheep was compared with that of humans. RESULTS: On an anatomical basis, we found the sheep to be a suitable model for studying the pathophysiology of spinal cord trauma and disorders relative to humans. CONCLUSIONS: To properly assess the effect of various pathological processes on the spinal cord, an anatomically valid model is required. This study established that the sheep is a suitable animal model for studies of this type.

Animals↗