Biomedical subjects

U Rembold

Publications and source records attributed to U Rembold.

5 recordsLinked to original sources

PubMed1998

A system for robot assisted maxillofacial surgery.

In maxillofacial surgery the quality of the surgical outcome mainly depends on the experience of the operating surgeon. Thus we intend to support the surgeon before and during surgery in order to enhance the surgical results. On the one hand this implies the use of image processing, three dimensional modelling techniques and visualization techniques of medical image data, on the other hand planning systems, intraoperative navigation devices and surgical robots are needed. In this paper a complex expert system is presented, which uses a planner for generating treatment plans, an infrared navigation for monitoring both patient, robot, and surgical tool, and a surgical robotic system in order to work on bone. Special stress is laid on the architecture of the planning system, the structure of the treatment plans, and the intraoperative communication protocols.

Algorithms↗

PubMed1998

Knowledgebased segmentation.

The segmentation of medical images like CT or MRI scans represents a great challenge to researchers in computer vision, due to the variability of the individual anatomy and the different characteristics of the scanning systems. As an anatomical knowledge base improves the recognition of structures in CT or MRI scans, we chose a knowledge based segmentation in our approach, which will be explained in the following.

Algorithms↗

PubMed1997

[Robotics in oral and maxillofacial surgery. Possibilities, chances, risks].

Robot systems are being tested in stereotactic neurosurgical interventions, orthopedic surgery of the hip or knee and advancal endoscopic systems for minimally invasive surgery. In contrast to most industrially manufactured products, objects for medical treatment are characterized by plasticity as well as by complex and individual forms. Thus, features of robots in this field have to be further developed in terms of advanced sensory and specific micromotoric systems. Safety and cooperation between surgeon and robot on the patient in the operating room have to be guaranteed. Extensive three-dimensional diagnosis, computer-aided planning and simulation of the intervention as well as sensory systems that monitor the actual performance of the operation are mandatory parts of this concept. In our interdisciplinary study, we aim to examine whether a robot-given a complete preoperative planning and simulation procedure-is able to perform certain surgical operations more precisely than the surgeon. Examples are drilling with depth control, shaping of bone surface by milling, sawing with defined depth in cranial osteotomies, defined preparation of implant sites and the positioning and insertion of dental and other surgical implants, whereby autonomous employment of the robot is not that which is aspired to in these interventions but rather the interactive support of the surgeon.

Humans↗

PubMedDate not supplied

[Clinical trends in 520 twin pregnancies in 22 years].

In the last 22 years 520 twin pregnancies were seen at the Department of Obstetrics and Gynecology, University of Ulm. The material was analyzed retrospectively according to the 4 time periods 1965-1974, 1975-1980, 1981-1983, and 1984-1987. An equal-size group of singleton pregnancies was used as control. 1. By the 20th week the diagnosis had been established in 67% between 1984 and 1987 and 29% between 1975 and 1980. 2. A cervical cerclage was most commonly done between 1981 and 1983 (75%). The frequency decreased afterwards and a cerclage was only done in 18% in 1987. 3. Tocolytic agents were used in 7% between 1965 and 1974 and in two thirds of cases in the last years. 4. Hospital admission before delivery was most common between 1975 and 1980 (33%). In the last 7 years it was only half as common (15%). 5. There was no difference in the frequency of preeclampsia and eclampsia between singleton and twin pregnancies in the last years. 6. Maternal hemoglobin levels below 10% were more common in twin pregnancies than in the control group: Before delivery 11%, after delivery 22% in the twin pregnancies, compared with 6% and 4% in the singleton pregnancies. 7. There was no increase in the duration of pregnancy in the last 22 years. The difference between actual birth date and estimated date of delivery remained about the same in the 4 examined time periods: 21 days, 20 days, 21 days, 27 days. There was a slight increase in the frequency of delivery before the 37th week in twin pregnancies: 38%, 41%, 43%, 47%.

Female↗

PubMedDate not supplied

[Perinatal aspects of 520 twin deliveries between 1965-87 at the Ulm University Gynecologic Clinic].

1. Birth induction in twin pregnancies was substantially reduced to 6% in last few years (1984-87) as opposed to 21% between 1975 and 1980. 2. Premature rupture of the membrane increased in the last years. At a rate of 33% is occurred nearly twice as often as with singletons (18%). A waiting policy increasingly adopted in such cases resulted in 21% of the twin group and 9% of the singleton group being born as late as 48 hours and beyond after membrane rupture. 3. The frequency of Caesarean sections performed in twin pregnancies rose dramatically over the last 22 years: 16%, 36%, 43%, 45%. With singletons, the tendency is reverse: 6%, 22%, 15%, 9%. One of the reasons why Caesarean sections are so markedly on the increase is that the frequency of immaturity in twins is steadily rising. In the past two decades the percentage of second twins less than 2500 grams birth weight rose from 35% to 71%. 4. Labour duration exceeding 12 hours increased from 8% to 21%. The same applies to the expulsion time of the first twin which rose on average from 10 to 21 minutes. 5. Manual delivery of the placenta remained at a steady rate of 25%, compared to 10% after singleton deliveries. 6. Hospitalization time exceeding two weeks decreased in the study period from 33% to 5%. 7. The perinatal mortality rate of twins could be halved in the period from 1965 to 1987, to less than 4%. The frequency of Caesarean sections, on the other hand, increased threefold to 48% now.(ABSTRACT TRUNCATED AT 250 WORDS)

Cesarean Section↗