Biomedical subjects

D Neuhoff

Publications and source records attributed to D Neuhoff.

5 recordsLinked to original sources

PubMed2006

Osseointegration of hollow cylinder based spinal implants in normal and osteoporotic vertebrae: a sheep study.

INTRODUCTION: Osteoporosis is not only responsible for an increased number of metaphyseal and spinal fractures but it also complicates their treatment. To prevent the initial loosening, we developed a new implant with an enlarged implant/bone interface based on the concept of perforated, hollow cylinders. We evaluated whether osseointegration of a hollow cylinder based implant takes place in normal or osteoporotic bone of sheep under functional loading conditions during anterior stabilization of the lumbar spine. MATERIALS AND METHODS: Osseointegration of the cylinders and status of the fused segments (ventral corpectomy, replacement with iliac strut, and fixation with testing implant) were investigated in six osteoporotic (age 6.9 +/- 0.8 years, mean body weight 61.1 +/- 5.2 kg) and seven control sheep (age 6.1 +/- 0.2 years, mean body weight 64.9 +/- 5.7 kg). Osteoporosis was introduced using a combination protocol of ovariectomy, high-dose prednisone, calcium and phosphor reduced diet and movement restriction. Osseointegration was quantified using fluorescence and conventional histology; fusion status was determined using biomechanical testing of the stabilized segment in a six-degree-of-freedom loading device as well as with radiological and histological staging. RESULTS: Intact bone trabeculae were found in 70% of all perforations without differences between the two groups (P = 0.26). Inside the cylinders, bone volume/total volume was significantly higher than in the control vertebra (50 +/- 16 vs. 28 +/- 13%) of the same animal (P<0.01), but significantly less (P<0.01) than in the near surrounding (60 +/- 21%). After biomechanical testing as described in Sect. "Materials and methods", seven spines (three healthy and four osteoporotic) were classified as completely fused and six (four healthy and two osteoporotic) as not fused after a 4-month observation time. All endplates were bridged with intact trabeculae in the histological slices. CONCLUSIONS: The high number of perforations, filled with intact trabeculae, indicates an adequate fixation; bridging trabeculae between adjacent endplates and tricortical iliac struts in all vertebrae indicates that the anchorage is adequate to promote fusion in this animal model, even in the osteoporotic sheep.

Animals↗

PubMed2005

Anodic plasma chemical treatment of titanium Schanz screws reduces pin loosening.

OBJECTIVE: This study was designed to assess the benefits of a new Anodic Plasma Chemical calcium-phosphate (APC-CaP) surface treatment on reducing pin track infection and pin loosening in comparison to anodized titanium (Ti) during external fracture fixation. METHODS: A tibial midshaft, transverse, 6-mm gap osteotomy was created in 17 adult female Swiss alpine sheep. The tibia was stabilized with an external fixator and 4 Schanz screws of Ti or APC-CaP-treated Ti. The sheep were examined during a 12-week observation period. Infection was assessed with weekly clinical pin track grading and microbiologic assessment at sacrifice. Pin loosening was assessed by grading for radiolucency on biweekly radiographs and by measuring extraction torque on pin removal. In vivo bending stiffness measurements were performed to determine gap healing. A qualitative histologic assessment of the tissue adjacent to pin sites was also performed. RESULTS: A trend (P = 0.056) for less infection around APC-CaP pins was found at 6 weeks, but the strength of this difference diminished with time. Significantly more radiolucency was found around Ti pins after 8 (P = 0.011) and 12 (P < 0.001) weeks. At all pin sites, the extraction torque for APC-CaP pins was higher than for Ti pins (P = 0.007). No difference in the progression of gap healing was found. Histology showed bone growth at the implant surface in the form of distance osteogenesis for Ti and contact osteogenesis for APC-CaP. CONCLUSIONS: This study has shown that the APC-CaP surface improves the clinical performance of Ti pins with respect to pin loosening and pin track infection.

Animals↗

PubMed2004

Establishing dental hygiene education in Germany: current facts and future perspectives.

As there is a marked need to increase the number of dental hygienists (DHs) working in German dental practices, efforts are being made to establish dental hygiene education in accordance with international standards. However, as current German legislation does not envisage a perennial full-time training programme, dental hygiene education may currently be provided within a modular concept only. The basic qualification for enrollment in a modular hygienist training programme of this kind is accredited vocational training as a dental assistant (DA), followed by board-certified continuing education as an oral prophylaxis assistant. Thus, the current system of advanced training for qualification as a DH is subject to at least 6 years' work experience in the field of dentistry. A 950-h full-time advanced training course, meeting all the requirements of this concept, was established by the Westphalia-Lippe Dental Association in cooperation with the University of Münster. The curriculum underlying this programme was outlined considering the recommendations for dental hygiene education issued by the European Federation of Periodontology, although reduced in standards to comply with current German legislation. In addition, the recommendations for American Dental Hygiene education by the American Dental Association were used as a guide for programme development. The contents and implementation of the Münster Dental Hygienist Curriculum may allow the professional competence generated during practical work experience to be linked with international requirements of dental hygiene education.

Accreditation↗

PubMed1989

Cesarean birth for failed progress in labor.

"Failure to progress" is the leading indication for primary cesarean section and has a major impact on the escalating cesarean birth rate in the United States. We investigated the labor and delivery records of nulliparous women at term with vertex presentations admitted to the clinic and private services of our hospital to determine the importance of different management strategies associated with operative deliveries. Birth weights and immediate neonatal outcome were identical between the clinic and private services. The cesarean birth rate on the clinic service was 5.2%, compared with 17.1% on the private service; 80% of the abdominal deliveries on the private service were for "failure to progress." Epidural use rates were similar on both services and were associated with a 70% incidence of oxytocin augmentation. Once oxytocin augmentation became part of labor management, a 14-fold increase in cesarean sections was observed for the private service, but oxytocin had no impact on the cesarean birth rate in the clinic service. The placement of an intrauterine pressure catheter and an approach to the use of oxytocin that might be characterized as "selective active management" were necessary to achieve efficient uterine action in a timely fashion, permitting a high likelihood of vaginal birth on the clinic service.

Anesthesia, Epidural↗

PubMed1981

Intestinal disaccharidases in malnourished infant rats.

In infants suffering from protein-calorie malnutrition, the decreased intestinal mucosal lactase specific activity could be due either to the protein-calorie malnutrition or to the commonly associated enteritis (viral or bacterial) and intestinal parasites. We studied intestinal mucosal disaccharidase (lactase, sucrase, and maltase) specific activity in suckling (1 and 2 wk old), weanling (3 wk old), and postweaning (4 and 6 wk old) control and growth-retarded (malnourished) rats. Growth retardation was induced by feeding mother rats and postweaning rats a diet deficient in protein. In the malnourished rats, with few exceptions, specific activity of the disaccharidases in the intestinal mucosa were similar to those in the corresponding control groups of rats. However, because of marked mucosal atrophy total intestinal mucosal disaccharidase activities were more than 50% lower in the malnourished rats. These findings suggest that the specific activity of the intestinal mucosal disaccharidases is not affected by malnutrition per se.

Animals↗