Patrick Stelzer

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High accurate absolute robot positioning is a requirement, and still a challenge, in many applications, such as drilling in the aerospace industry. The accuracy is affected due to many sources of errors from robot model, tool calibration, sensor and product uncertainties. While model-based error compensation cannot reach the desired accuracy, sensor-based(More)
Fifty-one children, aged 1.8 to 21 years (mean, 11.4) with aortic valve replacement using a pulmonary autograft are reviewed. Twenty-nine were intra-aortic implants and 22 were root replacements. There was one operative death, no late deaths, and two have required reoperation. Actuarial freedom from reoperation was 93% +/- 5.5 at 5.6 years. Freedom from(More)
The use of the patient's pulmonary valve for replacement of the patient's diseased aortic valve was introduced and developed by Mr. Donald Ross. Its demonstrated durability, freedom from thromboembolism, and potential for growth has led to increased utilization of this technique. Modifications of the earlier techniques have led to a reproducible operation(More)
A comparison of allograft and autograft (pulmonary) replacement of the aortic valve has, to our knowledge, not been done in America. Fifty-seven patients (age range, 2 to 70 years; mean age, 30 years) underwent 59 operations for replacement of the aortic valve (20) or entire left ventricular outflow tract (39) using autograft (35) or allograft (24) valves.(More)
To assess growth potential and hemodynamic sequelae of pulmonary autograft valves implanted into aortic outflow tracts of children, we reviewed our experience with 37 patients (2-21 years) from August 1986 to December 1990. Twenty patients had predominantly aortic stenosis (AS), and 17 had aortic insufficiency (AI). Operative mortality was 3%. Two technical(More)
Pulmonary valve autograft replacement of the aortic valve has been performed in nine patients in an effort to duplicate in the United States the experience of Sir Donald Ross in London. Four male and five female patients ranging in age from seven to thirty-four years have been operated on for indications of aortic stenosis in six and aortic regurgitation in(More)
Homograft replacement of the aortic valve has inherent advantages for the patient in terms of decreased incidence of thromboembolism, endocarditis, and anticoagulation-related complications. Limitations in its use stem from a significant incidence of postoperative aortic regurgitation, related to difficulty with consistent commissural and sinotubular(More)