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Biomedical subjects

E Mayr

Publications and source records attributed to E Mayr.

At least 19 recordsLinked to original sources

First results with the trochanter fixation nail (TFN): a report on 120 cases.

A complication rate between 4-18% for the conventional osteosynthesis of the proximal femur fracture continues to be unacceptable even if increasing age and co-morbidity of patients are taken into account. Therefore, new intramedullary techniques are under development, and we here report our results with the novel trochanteric fixation nail (TFN). During the study period (March 2003-February 2004) all patients with a trochanteric fracture Type A1-A3 (AO/ASIF classification) were eligible for the study, and 120 patients (mean age 81 years, range 47-100; male/female 1:4) subsequently enrolled. Most frequent was the (according to the AO classification) A.2.1. type of fracture (n=39) and the A.2.2. fracture (n= 39). Operation time from cut to stitch was 45 mins (minimal 21/maximal 194). Thirty-seven (31%) postoperative X-rays were classified as very good, 60 (50%) as good, 18 (15%) as satisfying and five (4%) as bad post-reposition results according to the Garden Alignment Index. The clinical results were documented by the time of hospital stay, postoperative mobilization and time of rehabilitation compared to the old social status. Time to hospital discharge was 17 days (9 /25). Overall complication rate was 7.5% (9 patients) with 5.8% [7] local wound infection; 1.6% [2] cutting out of the helical blade through the cortex of the femoral head. We had three (2.5%) hospital deaths in our patient group. We conclude that TFN is a safe and reliable technique. Compared with techniques like PFN and Gamma-nail, clinical results are excellent with less complications.

Aged↗

[Reduction of the amputation rate in bone and soft tissue sarcoma by interdisciplinary cooperation].

On the basis of three patients with bone and soft tissue sarcoma,we would like to illustrate the necessity of a well working inter-disciplinary cooperation of radiologists, internal oncologists, radiation therapists, orthopaedic surgeons and plastic surgeons. Functional extremity preservation in sarcoma patients can be achieved by a good interdisciplinary management without im-pairing the total prognosis of the patients. Patients with sarcoma should be treated in centres in which all specialised divisions are experienced and well trained in the treatment of tumour patients. Only then can a promising approach be achieved.

Adolescent↗

The effect of fixation and location on the stability of the markers in navigated total hip arthroplasty: a cadaver study.

In navigated total hip arthroplasty, the pelvis and the femur are tracked by means of rigid bodies fixed directly to the bones. Exact tracking throughout the procedure requires that the connection between the marker and bone remains stable in terms of translation and rotation. We carried out a cadaver study to compare the intra-operative stability of markers consisting of an anchoring screw with a rotational stabiliser and of pairs of pins and wires of different diameters connected with clamps. These devices were tested at different locations in the femur. Three human cadavers were placed supine on an operating table, with a reference marker positioned in the area of the greater trochanter. K-wires (3.2 mm), Steinman pins (3 and 4 mm), Apex pins (3 and 4 mm), and a standard screw were used as fixation devices. They were positioned medially in the proximal third of the femur, ventrally in the middle third and laterally in the distal portion. In six different positions of the leg, the spatial positions were recorded with a navigation system. Compared with the standard single screw, with the exception of the 3 mm Apex pins, the two-pin systems were associated with less movement of the marker and could be inserted less invasively. With the knee flexed to 90 degrees and the dislocated hip rotated externally until the lower leg was parallel to the table (figure-four position), all the anchoring devices showed substantial deflection of 1.5 degrees to 2.5 degrees . The most secure area for anchoring markers was the lateral aspect of the femur.

Arthroplasty, Replacement, Hip↗

Uncompromised quality of the cement mantle in Exeter femoral components implanted through a minimally-invasive direct anterior approach. A prospective, randomised cadaver study.

A complete cement mantle is important for the longevity of a total hip replacement. In the minimally-invasive direct anterior approach used at the Innsbruck University hospital, the femoral component has to be inserted into the femoral canal by an angulated movement. In a cadaver study, the quality and the extent of the cement mantle surrounding 13 Exeter femoral components implanted straight through a standard anterolateral transgluteal approach were compared with those of 13 similar femoral components implanted in an angulated fashion through a direct anterior approach. A third-generation cementing technique was used. The inner and outer contours of the cement mantles was traced from CT scans and the thickness and cross-sectional area determined. In no case was the cement mantle incomplete. The total mean thickness of the cement mantle was 3.62 mm (95% confidence interval 3.59 to 3.65). The mean thickness in the group using the minimally-invasive approach was 0.16 mm less than that in the anterolateral group. The distribution of the thickness was similar in the two groups. The mean thickness was less on the anteromedial and anterolateral aspect than on the posterior aspect of the femur. There is no evidence that the angulated introduction of Exeter femoral components in the direct anterior approach in cadavers compromises the quality, extent or thickness of the cement mantle.

Arthroplasty, Replacement, Hip↗

First clinical and biomechanical results of the Trochanteric Fixation Nail (TFN).

Conventional osteosynthesis of proximal femur fractures is still affected by serious complication rates between 4-18%, even though advanced implant modifications and surgical techniques are common practice. In terms of increasing age and co-morbidity of patients this complication ratio is expected to increase even further in the immediate future. One major reason for implant failure is the decreasing stability potential of the implant due to a loss in mechanical properties of cancellous bone. Therefore, efforts in new intramedulary techniques specifically focus on the load bearing characteristics of the implant by developing new geometries to improve the implant-tissue interface. This investigation discusses first clinical results of the trochanteric fixation nail TFN (145 patients) and a biomechanical analysis of the blade/femur head interaction under different static loading conditions. The TFN shows promising performance in first clinical results. In the clinical study the overall complication rate was significantly lower compared to other similar osteosynthesis. For the investigation of the biomechanical stability of the helical TFN blade the following experiments were performed: Analysis of the axial load required for insertion of the blade by free rotation; measurement of the corresponding rotation angle for total insertion (32 mm) (n = 8); pull-out forces with suppressed rotation (n = 4); loads for rotational overwinding of the implant in the fully inserted condition (n = 4). All investigations were performed on human femoral heads. The bone mineral densities of the specimens were detected by QCT-scans. Prior to cadaveric testing the experimental set-up was validated (n = 8) by the use of synthetic foam blocks (Sawbone).

Aged↗

Contamination during removal of cement in revision hip arthroplasty. A cadaver study using ultrasound and high-speed cutters.

Instruments used in surgery which rotate or vibrate at a high frequency can produce potentially contaminated aerosols. Such tools are in use in cemented hip revision arthroplasties. We aimed to measure the extent of the environmental and body contamination caused by an ultrasound device and a high-speed cutter. On a human cadaver we carried out a complete surgical procedure including draping and simulated blood flow contaminated with Staphylococcus aureus (ATCC 12600). After cemented total hip arthroplasty, we undertook repeated extractions of cement using either an ultrasound device or a high-speed cutter. Surveillance cultures detected any environmental and body contamination of the surgical team. Environmental contamination was present in an area of 6 x 8 m for both devices. The concentration of contamination was lower for the ultrasound device. Both the ultrasound and the high-speed cutter contaminated all members of the surgical team. The devices tested produced aerosols which covered the whole operating theatre and all personnel present during the procedure. In contaminated and infected patients, infectious agents may be present in these aerosols. We therefore recommend the introduction of effective measures to control infection and thorough disinfection of the operating theatre after such procedures.

Aerosols↗

Parasite removal by natural wastewater treatment systems: performance of waste stabilisation ponds and constructed wetlands.

Parasite removal and low cost systems for wastewater treatment have become increasingly important requirements in developed and developing countries to safeguard public health from wastewater-associated intestinal diseases. Pilot and field-scale ponds and wetlands in Brazil and Egypt have been investigated for the fate and removal of eggs of human intestinal parasites from domestic wastewater. In northeast Brazil, parasite removal was investigated for a series of five waste stabilisation ponds treating raw wastewater. In Egypt, parasite removal was studied for Gravel Bed Hydroponic constructed wetlands treating partially treated wastewater. Influents to ponds and wetlands contained a variety of parasite helminth eggs (e.g. Ascaris, hookworm, Trichuris, and Hymenolepis spp.). The ponds consistently removed parasite eggs though rate of removal by individual ponds may have been related to influent egg numbers and extent of short-circuiting. Parasite eggs were reduced on average by 94% and 99.9% in the anaerobic and facultative ponds respectively. No eggs were found in effluent from the second maturation pond. In the wetland system, parasite removal varied with reedbed length. The majority of parasite eggs were retained within the first 25 m. Parasite eggs were reduced on average by 98% after treatment in 50 m beds and completely removed after treatment in 100 m beds.

Animals↗

[Tibial fractures].

Explore the source record for details and available documents.

Anti-Bacterial Agents↗

[Focal myositis--an indication for surgery? A case report].

This case report describes focal myositis, a rare inflammatory pseudotumorous disease previously not mentioned in the surgical literature. Most often a single muscle of the upper or lower extremity is affected. Usually the diagnostic process and treatment require a long time. We present a useful diagnostic cascade and a surgical therapy, which allows the histological differentiation between malignant and inflammatory disease. Even after partial resection of the tumor, the prognosis of focal myositis is excellent.

Diagnosis, Differential↗

[Is low intensity ultrasound effective in treatment of disorders of fracture healing?].

This prospective consecutive study judges the effectiveness of pulsed low-intensity ultrasound for treatment of boney healing disorders. 86 out of 100 treatments were successful. Although in these 100 cases 64 delayed unions and 36 nonunions were enrolled ultrasound therapy was performed as an alternative to the indicated operation in every case. Excluding ten cases of ununited fractures of the scaphoid no additional therapy was performed in any case. Stratifying the data no significant differences in healing rate and treatment time were observed between delayed unions and non-unions and between atrophic and hypertrophic healing disorders. Judging the healing rate of 86% one has to take into consideration that according to our in- and excluding criteria we had a preselected sample of patients. Nevertheless the effectiveness of pulsed low-intensity ultrasound for treatment of disorders of the fracture repair process is evident.

Adult↗

Retrograde injection of a nutrient vein with cement in cemented total hip arthroplasty.

An 80-year-old woman received a cemented total hip arthroplasty. The surgery was performed without intraoperative complications. Postoperative radiographs and a computed tomography scan revealed a nutrient vein perforating the femur, which was retrogradely filled with cement. An abdominal and thoracic computed tomography scan showed no further dissemination of cement.

Aged↗

[Hip replacement after failed internal fixation in patients with proximal femur fracture--a simple procedure?].

Between January 1995 and December 2000 we operated on 1 437 patients with fractures of the proximal femur. In 789 cases an osteosynthesis was performed and in 648 cases a prosthesis was implanted. In the group of patients with primary osteosynthesis we stabilized 89 fractures with screws, in 319 patients a dynamic hip screw (DHS) and in 381 patients a Proximal-Femurnail (PFN) were implanted. Because of major complications we had to reoperate on 42 patients (5.3 %) with primary osteosynthesis. For analysis of this high complication rate we studied the fracture type, the type of complication, the operation time, the primary and secondary implant type and the time of postoperative mobilisation in this group of 42 patients. We saw 27 type A and 15 type B fractures, according to the AO classification. In the patient group with complications 4 times a primary screw stabilisation was done, 22 dynamic hipscrews (DHS) and 16 proximal femurnails (PFN) were implanted. After changing the primary osteosynthesis into 15 hemiprostheses and 26 total prostheses of the hip, we found in over 30 % major complications. A change of the procedure after primary osteosynthesis has to be regarded as a more difficult operation than the primary implantation of a prosthesis.

Aged↗

Environmental and body contamination through aerosols produced by high-speed cutters in lumbar spine surgery.

STUDY DESIGN: A cadaver study to evaluate contamination in the operating room through the use of a high-speed bone cutter. OBJECTIVES: To determine the grade of contamination of animate and inanimate objects through an aerosol intraoperatively, produced by a high-speed cutter during lumbar laminectomy. SUMMARY OF BACKGROUND: In spinal surgery, high-speed cutters are used that produce an aerosol consisting of a mixture of irrigation solution, blood, and tissue debris. Such aerosols can be contaminated with potential pathogens. The surgical personnel and the environment are therefore exposed to a contamination risk. METHODS: Laminectomies at three points (L2-L4) were performed on a human cadaver using a high-speed cutting device. The aerosol produced by the irrigation solution was contaminated with Staphylococcus aureus ATCC 12600. To detect the contamination of the environment and of the surgical team, surveillance cultures were used. RESULTS: By air sampling, staphylococci were detected in the operating room at an extension of 5 by 7 m. The surgical team showed extensive face and body contamination with S. aureus. Despite protection by a barrier drape, similar contamination was observed on both the cadaver's head and the anesthesiologist. CONCLUSIONS: The use of high-speed cutters in spinal surgery produces an aerosol that can be contaminated with blood-borne pathogens from infected patients. This aerosol is spread over the whole surgical room and contaminates the room and all personnel present. It is therefore critical to ensure that effective infection control measures are performed, not only by the surgeons but by everyone present in the operating room. The room itself must be sufficiently disinfected after such procedures.

Aerosols↗

[Routine use of abdominal ultrasound and epigastric CT in polytrauma. Analysis oftherapeutic relevanc in 105 patients].

INTRODUCTION: A prospective analysis was done to determine the frequency of therapy relevance of abdominal computed tomography (CT) in multiple trauma patients in comparison to abdominal ultrasound (US). METHODS: We recorded all multiple trauma patients in the emergency room (n = 248) from August 1996 to July 1997 with an evaluation form and performed abdominal CT subsequent to US whenever the patient was hemodynamically stable and not in need of immediate surgery (n = 105). We documented the results of both methods and their impact on acute therapy. RESULTS: In 27 of 105 patients (25.7%) therapy management was influenced by both either US or CT. 76 patients (72.4%) showed normal US findings, followed by a CT which showed additional findings with therapeutic relevance in five patients (6.6%). Twenty-nine patients (27.6%) showed abnormal US findings. Compared to the therapeutic procedures proposed after the use of US the subsequently performed CT led to a change in therapy in 12 patients (41.4%). CONCLUSION: We conclude that if US is normal, additionally performed CT of the abdomen provides information of therapeutic relevance in only a limited number of cases. If US is abnormal, CT will have an important impact on therapy in a high number of patients.

Abdominal Injuries↗

Contamination risk of the surgical team through ROBODOC's high-speed cutter.

During cutting of the femoral cavity in the ROBODOC procedure, an aerosol cloud of irrigation fluid, blood, and tissue debris was seen. This cloud potentially is contaminated with bacterial and viral vectors, which is an infection risk for the surgical team. A flat and a ball cutter were tested in four standard situations macroscopically with a colored solution. In a second experiment, the cutter was exposed to a fluid contaminated with Staphylococcus aureus, and bacterial room contamination was detected using standard cultures. The aerosol cloud was seen in a 6 x 3.6-m area. Extension and concentration varied, depending on the irrigation situation. ROBODOC's high-speed cutter produces an aerosol cloud in an area in which all members of the surgical team are affected. Sufficient protection is necessary for everyone in the operating room.

Equipment Contamination↗

Radiographic results of callus distraction aided by pulsed low-intensity ultrasound.

OBJECTIVES: To determine whether pulsed low-intensity ultrasound (frequency of 1.5 megahertz, pulsed by one kilohertz, signal burst width of 200 microseconds, intensity of thirty milliwatts per square centimeter, and daily treatment time of twenty minutes per day) stimulates regenerate maturation after callus distraction. DESIGN: Prospective, controlled animal trial. METHODS: Operatively, we created a fifteen-millimeter defect in the right metatarsus of eighteen female mature merino sheep. A segmental transport was begun on Day 5 using a high-stiffness experimental ring fixator. The distraction rate was one millimeter per day divided into two increments of 0.5 millimeters each. On Day 21 after the operation, distraction was finished and the maturation period started and lasted until Day 84 after operation. During this period, Group 1 was treated with a daily twenty-minute low-intensity ultrasound stimulation (frequency of 1.5 megahertz, pulsed by one kilohertz, signal burst width of 200 microseconds, intensity of thirty milliwatts per square centimeter). Group 2 had no stimulation. Animals bore full weight. Plain radiographs in the anteroposterior view were taken every two weeks during the maturation period. After the animals were killed on Day 84, anteroposterior and lateral high resolution radiographs and computed tomography (CT) scans of the regenerate were performed. For each plain and high resolution radiograph, two different relationships (callus relation, the ratio of the amount of periosteal callus to the size of the space between the proximal fragment and transported segment; and interzone relation, the ratio of the fibrous callus interzone to the size of the new formed callus) were calculated. Using CT scan, callus area, bone density, and bone mineral content were evaluated. RESULTS: The results of interzone relation (both views) and callus relation (lateral view) in high-resolution radiographs and bone mineral content in CT indicate a significantly accelerated maturation of the regenerate in the ultrasound stimulated group even when a Bonferroni-Holm adjustment was used for multiple testing. CONCLUSION: Pulsed low-intensity ultrasound appears to stimulate the healing processes in the regenerate in this animal model and may have applicability in clinical practice.

Animals↗