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Biomedical subjects

G Ritter

Publications and source records attributed to G Ritter.

At least 145 records · Page 8Linked to original sources

[Intramedullary nailing as secondary intervention following prior use of external fixation].

The external fixation has its clear indications. In some cases, however, healing up of the bone fails to appear. This is caused partly by the gravity of the primary injury, partly by biomechanical reasons. The failure of a perfect fracture healing can require a change of the osteosynthesis procedure. Under certain conditions nailing provides good success. By means of 13 own cases conditions, indications and results of secondary nailing after prior external fixation osteosynthesis will be discussed.

Adult↗

[Necessary stability and biomechanics of fracture healing in external fixation osteosyntheses].

In recent years, many investigators have concerned themselves with improving the construction of the external fixator in order to achieve even greater stability. Clinical observations demonstrate a moderate callus formation and an often considerably delayed fracture healing resulting from such an extreme rigid mounting of the external fixator. This report presents biochemical considerations which indicate that extreme rigidity in the external fixator is not only unnecessary, but may even interfere with fracture healing and the formation of functionally stable bone.

Biomechanical Phenomena↗

[Special osteosynthesis-techniques for use on traumatic bone fractures in the region of hip and knee endoprostheses (author's transl)].

Special problems are associated with fractures of bones with implanted endoprostheses. These problems are a result of unusual fracture-types often combined with damage and loosening of parts of the prosthesis, the limited applicability of standard osteosynthesis-procedures and the impaired blood supply of the bone caused by the destruction of the medullary vessels after filling the medullary canal with bone cement. Special operative techniques for the treatment of those problem-fractures are demonstrated such as the extension of the prosthesis by an elastic shaft and the concentric osteosynthesis of an unstable acetabulum by a newly developed implant.

Acetabulum↗

[5-year scintigraphic study of children with Perthes disease. Diagnostic evaluation and therapeutic consequences].

The value of bone scintigraphy in the diagnosis and follow-up of Perthes disease has been studied in 179 patients. Amongst 63 patients with Perthes' disease, there were 11 in whom the diagnosis could be made by scintigraphy before there were radiological signs. This enables early treatment to be carried out and leads to a shorter course of the disease and improved end-results. Scintigraphy alone makes it possible to judge the actual state of revitalization of the necrotic femoral head. From this, it is possible to derive the indications for a displacement osteotomy before the radiological signs of a "head at risk" appear.

Adolescent↗

[Current therapy of chronic osteomyelitis (osteitis) in childhood].

The article reports on experience collected in the treatment of chronic osteomyelitis in children. Surgical procedure is described and attention is paid to indication and treatment with gentamycin polymethylmethacrylate chains. In 15 cases treated by the author, primary cure was achieved by this method in 13 children; additional surgical procedure became necessary in two cases.

Abscess↗

[Experimental investigations of the axial load carrying capacity of the long bones using Steinmann-pins (author's transl)].

This paper reports the results of experimental investigations of the axial load carrying capacity of the long human bones. These investigations were conducted using a commercial high precision materials testing machine. Force-transmission was effected by Steinmann-pins or screws drilled transversely into the various long bones. The measured loading capacities are reported for various sections of the long bones. Their importance in regard to biomechanics, application and dimensioning of compression osteosyntheses by external fixation is discussed in length.

Bone Nails↗

[Biomechanical model for the transmission of dynamic stresses to the long bones by means of an external fixator to stimulate bone formation].

A new biomechanical model using an external fixator is described, which produces physiological dynamic axial stresses on the long bones without causing harmful micromovements at the fracture site. The authors are of the opinion that their model will make it possible to stimulate fracture healing by influencing bone remodelling and tissue differentiation.

Biomechanical Phenomena↗

Rehabilitation for patients with multiple sclerosis?

In the epidemiological area of Southern Lower Saxony 92 patients with clinically definite or probable diagnosis of multiple sclerosis (MS) were interviewed and examined. This group contained a remarkably high percentage of benign cases (52%) in comparison with a sample of hospitalized patients. Neurological examination revealed spasticity and pareses to be the most important disturbances followed by ataxia and bladder/bowel problems. After a mean duration of 18.4 years, 52% received a pension and about 30% were still working full time. The pension was granted too early to 11 patients and vocational rehabilitation services would be required for 13 men. Although only half of the patients had an acceptable income, the socioeconomic situation of the families was adequate in 71%; 80% lived with their own families and could stay there in case more ambulant services were offered. Psychotherapeutic measures are required among these to relieve the stress within the families (present in 42%)and to improve the coping behavior (unsatisfactory in 60%).

Disability Evaluation↗

HLA-antigens and the prognosis of multiple sclerosis.

The histocompatibility pattern of 160 patients with multiple sclerosis (MS) living in the epidemiological area of Southern Lower Saxony was determined and compared to a control population. The only significant difference was the more frequent occurrence of DW2 in the patient group (44% vs. 21%). Taking a progression index (grade of disability divided by the duration of the disease) as a measure for prognosis no difference could be found between the DW2 positive and the DW2 negative patients. The reason why we could not confirm the worse prognosis for DW2 positive patients found by Jersild et al. (1973) and Raun et al. (1980) remains to be investigated.

Ethnicity↗

[Release and diffusion of methylmethacrylic monomers after the implantation of self curing bone cements. Study on laboratory specimens and animal experiments (author's transl)].

In this study the degree and the time interval of the release of toxic methylmethacrylic monomers in neighboring bone tissue has been investigated after implantation of self couring acrylic cements. It has been shown that the majority of unpolymerized monomers is diminuated by a biologically uneffective later polymerization; thus only a minor part of methylmethacrylic monomers undergoes diffusion. The processes occur mainly during the first 24 hrs after implantation and are below the laboratory detection after 2 weeks. Cement additives such as X-ray contrast materials (BaSO4 or ZrO2) do not influence these reactions. Among the cements investigated herein (CMW-bone cement, Surgical simplex, Palacos) pronounced differences in the release of residual monomers during the first week have clearly been demonstrated.

Animals↗

Characteristics of the resuscitated out-of-hospital cardiac arrest victim with coronary heart disease.

The clinical entry characteristics and medical history of 142 resuscitated out-of-hospital cardiac arrest victims with coronary heart disease were studied in order to identify factors that affect their long-term survival. The cardiac arrest event was classified as being secondary to an acute myocardial infarction (AMI) in 44% (62 of 142), an ischemic event (IE) in 34% (49 of 142) and a primary arrhythmic event (PAE) in 22% (31 of 142). The majority of patients in all groups had a history of angina pectoris. Twenty-seven percent of the AMI, 55% of the IE, and 71% of the PAE patients had a history of infarction. Ten percent of the AMI, 31% of the IE, and 55% of the PAE had used digitalis before their cardiac arrest. Cardiac arrest was the first cardiac event in 35% of the AMI, 16% of the IE and 6% of the PAE patients. One year after arrest, 89% of the AMI, 80% of the IE and 71% of the PAE were alive (p less than 0.01). Covariate analysis for more than 40 variables indicates that a high-risk group included 22% (31 of 142) of the cardiac arrest victims had 1- and 2-year survival rates of 71% and 55%, respectively, and was characterized as having used digitalis before arrest, experiencing blood urea nitrogen elevation and pulmonary congestion during the hospitalization for the event, and classification of the cardiac arrest event as a PAE. A low-risk group comprised 78% (111 of 142) of the survivors and had 1- and 2-year survival rates of 85% and 69%, respectively. These data indicate that cardiac arrest due to coronary heart disease is secondary to several mechanisms related to subsequent survival.

Acute Disease↗