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Biomedical subjects

F Gebhard

Publications and source records attributed to F Gebhard.

At least 37 records · Page 2Linked to original sources
PubMed2003

[Prediction of mortality, mobility and admission to long-term care after hip fractures].

INTRODUCTION: Surgical treatment, discharge planning and rehabilitation procedures are rarely based upon defined assessment procedures. It might therefore be useful to develop simple and reliable screening tools to identify patients for early discharge, intensified rehabilitation and limited treatment. PATIENTS AND METHODS: 234 patients were initially contacted. From these 217 gave informed consent. The reported study included the 134 home dwelling elderly. All patients could be contacted or died after six month. Thus,data from more than 90% could be used for the analysis. The six month mortality was 10%. A population based cohort of elderly patients referred to five local hospitals was tested. Mortality, institutionalisation and mobility were defined as major outcome criteria. Only information that was available during the first week of treatment was used in the model. Predictors expressed as odd ratios (OR) were calculated using logistic regression with variable selection. RESULTS: The most important predictors for institutionalisation were age, inability to eat without assistance, postoperative night time confusion, stroke history, cognitive deficit and fear of falling. Outdoor mobility was strongly associated to the preoperative ADL performance measured as the Barthel-Index, history of malignancy and fear of falling. Six month mortality was associated with male sex, the Barthel-Index and fear of falling. DISCUSSION: It seems feasible to improve postoperative resource allocation by predictor led stratification. This need to be tested in intervention trials under the specific condition of the German health care system.

Activities of Daily Living↗
PubMed2003

[OR-manager: surgeon or anaesthetist?].

The heart of any surgical department is the operating room (OR) area. Any disturbances in the daily routine will affect the work flow of the whole hospital. On account of its central function, with numerous connections to other departments, the OR is the crystallisation point for deficiencies in various events and processes. As an example, the major complaints made by a surgical department regarding workflow and communication are outlined. To solve these problems, an "OR organization" team was established, which worked on the basis of a newly developed OR statute. Within 1 year the employees were more contentment and the workflow had improved. However, even in the second year of central OR management there is still the need to further stabilize the system as mismanagement still occurs.

Anesthesiology↗
PubMed2003

[Radiation dosage in orthopedics -- a comparison of computer-assisted procedures].

Since the 1990s, computer-assisted methods have been well-established in the field of orthopedics and traumatology. In addition to the proven improvement in the field of surgical precisioncompared with conventional techniques, the decrease in the amount of emitted ionizing radiation inside of the operating room was cited to constitute an additional major advantage of computer-based navigation. The goal of this study was to quantify X-ray dose values exposed during both conventional methods and computer-assisted procedures, the latter being performed using a C-arm device SIREMOBIL Iso-C3D (Siemens Medical Solutions). The clinical measurements were supplemented by laboratory experiments using a pinpoint ionization chamber placed inside a standard lucite phantom. The clinical part of the study investigated the application of new, i.e. computer assisted, techniques in comparison with conventional procedures on in total 42 patients experiencing surgery either on their lower extremities (n = 14) or on the spine (n = 28). The techniques applied were: (1) conventional surgical procedure, (2) CT-based navigation, (3) C-arm navigation, and (4) Iso-C3D-navigation. The main focus of the clinical evaluation was the determination of radiation dose values by means of thermoluminescence dose meters, accompanied by the registration of the operation times of the X-ray tube during a surgical intervention. The conclusions from the clinical studies are in agreement with the results from the laboratory measurements. Computer-assisted techniques led to a significant reduction in X-ray dose exposure and drastically shortened irradiation times. The most pronounced decrease in the emission of ionizing radiation was achieved in case of the Iso-C3D-navigation, which has only recently been introduced into clinical practice, i.e. during runtime of this study.

Humans↗
PubMed2003

[Fatal outcome after multiple trauma. The thoracic injury as the decisive factor].

In patients suffering from multiple injury, chest trauma is often the main cause of fatality. A case report is given and the literature reviewed.A 49 years old motorcyclist hit a car frontally in a road accident. After primary stabilization and first clinical care, he was transferred to our trauma centre because of severe chest injury, suspected pericardial effusion and lesion of the thoracic aorta. Initial diagnostics (plain radiographs, CT scan of thorax, abdominal ultrasound, echocardiography) showed left-sided serial rib fractures, a fracture of the left scapula, a hematopneumothorax left-sided, bilateral lung contusion, a small pneumothorax of the right side, a minimal pericardial effusion and a small splenic hematoma. The patient was treated in the intensive care unit, and the situation was initially stable. After 12 h, respiration deteriorated and a bronchoscopy showed filling of the airways with mucous fluid. The CT scan showed a worsening of the pulmonary damage and increasing pericardial fluid compression. A pericardiotomy was carried out, but the situation remained unstable. The patient was treated with invasive ventilation (PEEP>10, FiO2>0,5). Sudden severe bleeding out of left lower lobe was managed by thoracotomy and lobectomy. The patient remained unstable and died 95 h after the accident. This case shows that the severity of chest trauma does not necessarily correlate with the initial clinical and radiological findings. Even with all diagnostic and therapeutic procedures, a fatal outcome could not be prevented. This demonstrates the role of chest injury as a major and unforeseeable cause of death in multiple trauma patients.

Accidents, Traffic↗
PubMed2003

[Navigation of tumors and metastases in the area of the thoraco-lumbar spine].

In this clinical feasibility study, CT-based verification of the efficacy of navigated decompression and pedicle screw placement in patients who had tumor-related posterior surgery was demonstrated. Eighty-six percent of the pedicle screws were positioned centrally in the bone without perforation; in all patients accurate decompression was seen. The accuracy of transpedicle screw implantation postoperatively was investigated with CT. In contrast to other published studies, no postoperative neurologic deterioration was seen in the patients as a result of using computer-aided surgical procedures. At the same time we were able to achieve complete decompression of the neural structures for radiologic and neurologic findings. Because of inaccurate registration, it was not possible to use computer-aided implantation surgery for 15% of the pedicles and, therefore, a conventional fluoroscopic approach was used. Our initial results indicate that computer-aided frameless navigation of tumor surgery of the spine is a safe technique which improves surgical performance during posterior decompression and transpedicle stabilization. In addition, CAS surgery improved the intraoperative information about the tumor and the current surgical intervention during decompression. Nevertheless the technique should be used only by experienced surgeons who can, if required, continue the operation using conventional techniques. Furthermore, the surgeon should have a complete theoretical understanding of the navigation system to minimize possible misinterpretation of computer guidance information.

Bone Screws↗
PubMed2003

[Precision of navigation-assisted surgery of the thoracic and lumbar spine].

The goal of these studies was to evaluate the accuracy of in vivo and in vitro application of CT- and C-arm-based navigation at the thoracic and lumbar spine. With CT based navigation, 82 pedicle screws were consecutively inserted, 53 into the thoracic and 29 into the lumbar spine. Seven (13%) perforations were detected at the thoracic spine and two (7%) at the lumbar spine. Additionally, minor perforations below the thread depth were seen in six (11%) thoracic and in two (7%) lumbar instrumentation. With C-arm-based navigation, 74 screws were consecutively placed into 38 thoracic and 36 lumbar pedicles. Perforations were noted in ten (26%) thoracic and four (11%) lumbar implants. Minor perforations were observed in another nine (24%) thoracic and ten (28%) lumbar pedicles. The observer-independent and standardized in vitro study based on a transpedicular 3.2-mm drill hole aiming a 4-mm steel ball in a plastic bone model showed pedicle perforations of the drill canal only in thoracic vertebrae, 1 of 15 in CT-based and 3 of 15 in C-arm navigation. The quantitative calculation of the smallest distance between the central line through the drill canal and the center of the steel ball resulted in 1.4 mm (0.5-4.8 mm) for the CT-based navigation at the thoracic spine and in 1.8 mm (0.5-3 mm) at the lumbar spine. For the C-arm based navigation the distance was 2.6 mm (0.9-4.8 mm) for the thoracic spine and 2 mm (1.2-3 mm) for the lumbar spine. In our opinion, the clinical results of the comparative accuracy of CT- and C-arm-based navigation in the present study showed moderate advantages of the CT-based technique in the thoracic spine, whereas CT- and C-arm based navigation had comparable perforation rates at the lumbar pedicle. The results of the experimental study correlated with the clinical data.

Bone Plates↗
PubMed2002

[Time optimized modern shock room management using digital techniques].

Emergency room management means time management. A time and four color based algorithm is described to improve workflow, follow up of diagnostic procedures and initial treatment. As a result introducing the time based interdisciplinary emergency algorithm within 60 minutes all necessary treatment and diagnostic procedures were completed. This algorithm is an effective tool to improve emergency room treatment.

Algorithms↗
PubMed2002

[Costs for acute, stationary treatment of polytrauma patients].

Are the costs required for a polytraumatised patient sufficiently paid by the health care companies?The study population consisted of 71 polytrauma patients. The treatment-costs were calculated and compared with the reimbursements. The mean patient age was 38.0 years with a mean injury severity score (ISS) of 23.0 points. The mean duration of hospitalisation was 25.9 days and the mean calculated cost per patient was Euro 21,866.30. The reimbursement was only Euro 16,863.03/patient. This leads to a financial deficit of approximately Euro 5,000/patient (Euro 167/polytrauma patient/hospital day) and nearly Euro 355,000 for all patients during the period of 1 year. The introduction of the DRG system endangers the high standard of polytrauma treatment because of insufficient reimbursement.It is necessary to consider the implementation of an additional polytrauma-reimbursement based on the injury severity and duration of hospitalisation. The concentration of the patients in trauma centres, where the optimum of therapy is guarantied, leads in these hospitals to a continuously increasing deficit. The latter may be deleterious for the concept of "trauma centers" in the future.

Adult↗
PubMed2002

[Injury prevention in the elderly population].

Injuries in the elderly population have more considerable consequences (more difficult treatment, higher costs,worse outcome) than in the younger population. Therefore, the prevention is especially important. The majority of the injuries are caused by traffic accidents and falls. TRAFFIC ACCIDENTS: An analysis of the current injury situation in elderly road users (65 years and older) involved in road traffic accidents was intended to allow conclusions regarding future prophylaxis. FALLS: Falls are mostly caused by numerous factors. The most important predictors for falls are dementia,Parkinson-Syndrome and neurologic deficits after cerebrovascular insults. The most important symptoms, that indicate an increased risk for fall are gait abnormalities, balance lack and underweight. The most important anamnestic indications are more than one falls in the recent 90 days, need for assistance in daily living and prevailing medication. Another important factor is the residential setting (lighting, stairs, floor conditions,bath installations). The most affective protective interventions involve multiple factors. The incidence of falls could be reduced by 30%. The hip protector is an effective protection against proximal femur fractures. which is the most frequent fracture in the elderly population that requires treatment as an inpatient. Injury prevention in the elderly population is an interdisciplinary task as for example shown by the successful fall clinics in the anglo-american area.

Accident Prevention↗
PubMed2002

[Sources of error and risks in CT based navigation].

Based on the experience of 4 cervical, 102 thoracic/lumbar pedicle screw and 14 transiliosacral screw implantations all problems and complications were collected. Problems noted within the data collection in the preoperative CT were an incomplete acquisition of the surgical target (n = 3), an exceeding of the processable scan slices (n = 1) and a non focused field of view. Transmission of the CT datas often were documented as incomplete (n = 16). Segmentation of the CT dataset turned out to be the significant problem with incorrect differentiation of the bone-soft tissue transition (n = 2), where as the choice of the matching points and the trajectories did not provoke any mistakes in the planning modus. The intraoperative matching of both corresponding datasets was insufficient (n = 7), while the assignment of the CT dataset to the correct vertebral was not a major problem (n = 1). Navigation was not possible (n = 2) due to an instability of the spinal process. All fiducial based matching procedures (pelvis) were carried out without any problems. During intraoperative navigation potential complications resulted from deformation of instruments (n = 1) and interaction of instruments and the data reference base (n = 2). Further, the CT-based navigation of fractured vertebrae or unstable iliosacral joints is not safe, because dislocations between acquisition of the dataset and operation will lead to misguidance.

Artifacts↗
PubMed2002

[Neurogenic spinal deformities. I. Conservative and surgical treatment of spinal deformities].

Neurogenic spinal deformities develop primarily due to insufficient dynamic stabilization against gravity. Unilateral muscle overactivity is another but rare cause. The aim of treatment is to provide stability as well as to prevent deformity. In mild cases, the treatment of choice is a spinal brace because stabilization can be combined with residual mobility and adequate correction of shape. Seating shells are more readily accepted but less appropriate for this purpose. In severe cases, surgery is a good option despite the considerable effort involved and high rate of complications.

Adolescent↗
PubMed2002

Operation planning of correction osteotomies in 3D.

This paper discusses an operation planning system for correction osteotomies. It is based on 3D data obtained from CT/MR of the bone and it allows to perform a 3D planning. The physician can individually determine anatomical landmarks for measuring geometric parameters of the bone like length, angle and torsion angle. In a virtual scene he or she can set a single cut or can remove/insert a wedge, dissecting the bones. The bone parts can be rearranged in 3D space. Optimization routines allow that the physician only defines the position of the cut, the orientation of the cut plane, the rearrangement of the bone and the optimization for the maximal overlap of the cortical bone can be processed automatically. The system is currently in use at the Trauma department at the University of Ulm. A case study shows the results by applying this system.

Bone Malalignment↗
PubMed2001

Spinal navigation in cervical fractures--a preliminary clinical study on Judet-osteosynthesis of the axis.

OBJECTIVE: To evaluate the accuracy of CT-based and computer-aided screw insertion into the pedicles of the axis using the method of Judet. Materials and Methods In two patients, four transpedicular implants of C2 were positioned using a computer-guided technique. One patient with iatrogenic destabilization of the posterior structures C3 and C4 and one patient with a hangman's fracture of the axis required pedicular fixation. In addition, intraoperative documentation of the additional time required for the navigation procedures was made. Finally, postoperative CTs of each patient provided further information about transpedicular implant localization. RESULTS: Image-guided implantation of screws was possible in all scheduled pedicles of the axis. In the postoperative CT scans, none of the inserted screws perforated the medial or lateral pedicle. All screws were accurately positioned within the pedicles, and no anterior perforation of the screws into the vertebral foramen was observed. CONCLUSIONS: Our initial results using computer-aided implantation of Judet screws showed that these screws were inserted correctly. However, it is important to realize that movements can occur in the vertebral arch and lateral mass during the time between preoperative CT and surgery. This possibility for movement should be taken into account when procedures such as CT-based insertion of image-guided screws into patients with fractures of the isthmus C2 are performed, because damage to neurovascular structures can result. Therefore, this navigation system should only be used by experienced surgeons who can, if necessary, continue the intervention with more conventional techniques. In addition, it is essential that the surgeon have a complete understanding of the principles of the tracking systems to prevent possible misinterpretation of computer-generated information.

Adult↗
PubMed2001

[New methods in polytrauma surgery. Results of a Study Congress at castle Reisenburg 27/28 February 2000].

Recently, in Germany the academic environment has changed and an upheaval occurred that directly do affect academic research activities. Increasingly, the funding of scientific projects is not provided anymore by the universities themselves or the government, but has to be acquired as grants. While in the past, research was conducted by single departments, nowadays and more and more in the future scientific networks have to be established by combining 'local' and even 'distant' knowledge. With this changing background in mind representatives of different scientific institutions met at the Reisensburg castle to discuss the current state and future trends in four major research fields: "Epidemiology of Severe Trauma", "Head Injury", "Pathophysiology of Damage to the Chest", and "Posttraumatic Soft Tissue Injury".

Germany↗
PubMed2001

[Influence of prosthesis design on intramedullary pressure formation in femur shaft implants of cemented hip endoprostheses].

The increase of intramedullary femoral pressure can lead to the intravasation of bone marrow and fat cells into the blood stream of the femoral vein and consequently into the pulmonary circulation. This effect is the same in intramedullary nailing and in the implantation of femoral stem prostheses. In a prospective study we evaluated the intraoperative, intramedullary pressure in the distal femur during the implantation of femoral stem prostheses with two different designs. In eight patients we implanted Müller straight stems and in another eight we implanted stem type Option 3000. Intramedullary pressure was recorded continuously by the implantation of a microtip pressure probe (piezoresistive principle, 50 Hz) in the distal femur. We found markedly higher pressure in Müller straight stem prostheses: range: 590-2,570 mmHg (median = 1,293, SD = 627 mmHg). Intramedullary pressure in stem prosthesis type Option 3000 was much lower: range: 59-574 mmHg (median = 289, SD = 219 mmHg). The differences were statistically significant (p = 0.0008). By changing the designs of femoral stem prostheses, the intramedullary pressure can be markedly reduced. In the case of elderly patients or those with pulmonary illness we recommend femoral stem prosthesis designs, which induce little increase in the intramedullary pressure, in order to reduce cardiopulmonary complications.

Bone Cements↗
PubMed2001

[Precision in standardized Iso-C-Arm based navigated boring of the proximal femur].

C-arm navigation is a new tool in computer assisted surgery. The aim of this study is to evaluate the accuracy of Iso-C-arm based drill holes in the proximal femur. In nine artificial proximal femura, two holes with an angle of 135 degrees and 100 degrees in relation to the shaft axis were drilled in the direction of the femoral head. The defined target of the 3.2 mm drillings was a 4 mm steel ball, which had previously been placed and fixed at the cranial center of the femoral head. All the drillings were standardized with a navigated drilling machine fixed to a frame which only allowed movement of the system in the direction of the drill. During navigation the positions of the drill before commencement and at the deepest point of the canal were recorded. After drilling all specimens were evaluated by CT, and the coordinates of the center of the start and the end of the drilled hole and the center of the ball were determined. Using vector calculation, the smallest distance between the straight line, defined by the center of the starting point and the end point of the drill hole, and the center of the ball was calculated. Additionally, the coordinates of the intersection between the perpendicular to the center of the ball and the straight line were determined (xv, yv, zv), to evaluate the direction of misplacement of the drilled canal in relation to the target. For the 135 degrees drill holes, a median of 2.5 mm for the smallest distance between the straight line, given by the center of the start and the end of the hole, and the center of the ball was investigated (range 1.6-3.7 mm). For the 100 degrees holes the median was 3.1 mm (range 1.8-4.2 mm). The main plane of deviation in all of the 135 degrees holes was posteriorly, whereas in the 100 degrees holes posterior deviation occurred in four cases, cranial in three cases, and in one case each caudal and anterior deviation occurred. In our opinion, the accuracy of fluoroscopy based navigation applied in the region of the proximal femur is sufficient and reproducible. This technique can be used for implant placement at the proximal femur in the future.

Equipment Design↗