Biomedical subjects

Ulrich Stöckle

Publications and source records attributed to Ulrich Stöckle.

4 recordsLinked to original sources

PubMed2005

Short term in vivo biocompatibility testing of biodegradable poly(D,L-lactide)--growth factor coating for orthopaedic implants.

Fracture healing can be stimulated by exogenous application of growth factors. Using porcine and rat models the efficacy of locally delivered IGF-I and TGF-beta1 from an implant coating has been demonstrated. A thin and biomechanical stable biodegradable poly(D,L-lactide) was used to coat implants and serve as a drug carrier. Due to reports of possible foreign body reactions caused by polymer materials in orthopedic surgery, this study investigated the biocompatibility of the polylactide implant coating and the locally released growth factors during the time course of rat tibial fracture healing (days 5, 10, 15, and 28 after fracture). Monocytes/macrophages and osteoclast were detected using an monoclonal antibody against ED1 (comparable to CD68 in mice and human). The antibody ED1 stains monocytes, macrophages and osteoclast in the bone marrow and in the newly formed fracture callus. A moderate density of the monocytes/macrophages was seen in the proximal part of the medullary canal, but almost no cells were detectable in the region distal to the fracture. The amount of stained cells increased during the observation time with a maximum at days 10 and 15 followed by a decrease at day 28. No differences were detectable between the investigated groups from day 5 to 15 post fracture indicating, that the used poly(D,L-lactide) or the incorporated growth factors do not evoke an elevated immunological response compared to the uncoated titanium implant at the investigated time points. A significantly higher amount of ED1 positive cells was measured 28 days after fracture in the control group compared to the groups with the coated implants. In conclusion, no indication of a foreign body reaction due to the use of the polylactide or the growth factors was found indicating a good short-term biocompatibility of this bioactive coating.

Absorbable Implants↗

PubMed2004

Which navigation when?

If a surgeon is considering purchasing a navigation system, several factors have to be evaluated including, the planned applications, the equipment already installed, and the specific knowledge of the surgeon. For use in traumatology, fluoroscopy and more specifically 3-D fluoro-based computer guidance is preferable. These technologies are based on intraoperative acquired arbitrary images in contrast to CT-based techniques, which refer to preoperative acquired images that represent a so called "cannel reality". However, image quality has to be considered as fluoro-picture quality depending on the anatomical area (eg long bones, spine, pelvis) and body mass index. CT-based navigation provides better image quality and accuracy but is not able to visualize reduction processes. Therefore personal experience in courses or by on-site teaching is recommended prior taking the decision.

Fluoroscopy↗

PubMed2004

Navigation at the spine.

Computer aided and computer navigated operative techniques have been used for the first time in neurosurgery and surgery of the spine. For computer aided surgery of the spine there are currently two different methods: CT-based and C-arm based techniques. The advantage of the CT-based technique is its accuracy especially in difficult anatomical regions like the cervical and upper thoracic spine, and the possibility of preoperative planning. The advantage of C-arm navigation is the broad intraoperative availability with the disadvantage of limited image quality in some regions of the spine eg, the upper thoracic spine. This last disadvantage has been dramatically improved by introducing 3-D C-arm navigation (ISO C 3-D, Siemens, GER). Generally, all methods enhance the precision of pedicle screw insertion. Clinical as well as experimental studies show an exact pedicle screw position using the computer navigated techniques in over 90% of cases. C-arm based navigational techniques are being constantly improved and the future will be CT-like images with instant intraoperative availability.

Bone Screws↗

PubMed2004

Clinical applications--pelvis.

Navigation procedures based on CT data were introduced into spinal surgery in 1994. Since then, the method has been used in other areas such as joint replacement, reconstructive surgery, and tumor surgery because of its high precision and reduced radiation exposure. The original CT-based spine module can be adjusted for pelvic surgery with the prerequisite that the positioning of the fragments is identical in CT and in the OR; otherwise a new dataset has to be acquired. Our experiences with CT-based navigation in pelvic surgery are explained on five percutaneous screw fixations and three tumor resections, including description of the technique. For modality-based navigation, the navigated procedure is performed in the CT suite with the advantage of immediate CT control of reduction quality and screw positioning. The technique is explained and illustrated on two cases. Fluoroscopy-based navigation has been used in trauma surgery since the late nineties. Since then, the method has been wide spread in the field of joint replacement and reconstructive surgery. Between June 2000 and December 2002, we performed 36 percutaneous screw fixations in the pelvis with postoperative x-ray and CT control. 35 of the 36 screws were placed correctly. In one screw, an anterior cortex perforation of the sacrum was seen in the CT without any neurological consequences. The Iso C 3-D fluoroscope has recently been approved for pelvic surgery. With the ability to reconstruct images, visualization of the acetabulum and the posterior pelvic ring, there is marked an improvement compare to conventional 2-D fluoroscopy. Thus, the field for navigation is also enhanced. Based on our clinical experiences, the indications for navigated techniques in pelvic and acetabular surgery are defined and illustrated.

Adult↗