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Biomedical subjects

M Ogon

Publications and source records attributed to M Ogon.

At least 19 recordsLinked to original sources
PubMed2003

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↗
PubMed2002

[Surgical treatment of idiopathic scoliosis and juvenile kyphosis].

Indication for operative treatment of idiopathic scoliosis and juvenile kyphosis is mainly cosmetic. There is also a higher incidence of pain in scoliosis patients, and reduced pulmonary function in severe deformity, especially in severe deformities present at the age of 5 years (early onset). Scoliotic curves of less than 30 degrees will not progress in adults, whereas curves of 50-75 degrees will further progress a mean of 25 degrees during 40 years. Progression in adults with juvenile kyphosis is not well documented. Operative treatment aims to stop progression, to control spinal growth, or to perform correction and fusion by spinal instrumentation and bone grafts. These goals can be achieved either by an anterior, a posterior, or a combined approach. Correction principles are compression, distraction, derotation and translation. The forces applied by correction are transferred by fixation devices (pedicle screws, anterior screws, hooks, sublaminar wires) to the spine. The higher correction forces are, the higher is the correction achieved, but also the risk of fracture and torn out implants. Mobilisation reduces rigidity and allows to achieve a better correction with equal forces. The best mobilisation techniques are disc excision, facet joint removal, and techniques to mobilise the thorax.

Adult↗
PubMed2001

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↗
PubMed2001

Radiographic evaluation of cervical spine trauma. Plain radiography and conventional tomography versus computed tomography.

Different imaging modalities are available for the diagnosis of cervical spine injuries. There is a controversial discussion about whether plain radiography (PR), conventional tomography (CTO) or computed tomography (CT) should primarily be used. PR and CTO are more often available and less costly than CT. Especially in second-care hospitals, CT is not always available. The diagnostic work-up in these centres has to rely on conventional techniques. The aim of this study was to define the role of PR supplemented by CTO in the diagnosis of cervical spine trauma in comparison to CT. Twenty-five patients were identified who underwent plain radiography (PR), conventional tomography (CTO) and computed tomography (CT) for the diagnosis of a cervical fracture. In 19 patients a fracture of the cervical spine was identified. All images were reviewed by two independent observers to estimate the interobserver variability. The highest detection rate was achieved by CT (18/18 fractures detected for observer 1/2), followed by CTO (16/16 fractures) and then PR (15/14 fractures). When the detection rates of PR and CTO are combined, 18 fractures were detected by each of the observers. The results were analysed for the dens and the rest of the cervical spine independently. For PR and CTO the detection rates were lower for fractures of the dens than for the rest of the cervical spine. We conclude that the combination of PR and CTO accurately detects fractures of the cervical spine compared with CT. If a fracture of the dens is suspected, the patients should be referred to CT due to its superior accuracy in this region.

Adolescent↗
PubMed2001

Aerosols produced by high-speed cutters in cervical spine surgery: extent of environmental contamination.

High-speed cutters are used in the surgery of the cervical spine. Such high-speed devices can produce an aerosol cloud. As a patient can be a reservoir for pathogens, with aerosol-borne paths of transmission, such an aerosol has to be seen as a potential risk of infection for health care professionals present during the surgery and for patients if micro-organisms are transferred through the medical personnel. The study was performed in order to measure the extension of environmental and body contamination through contaminated aerosols produced by a high-speed cutter. Three laminectomies (C4-C6) were performed on an intact human cadaver with a high-speed 0.6-mm ball cutter. A complete surgical setup was arranged, including surgical draping and a barrier drape to the anesthesiologist's workplace. Body and environmental contamination was detected by the use of surveillance cultures. The irrigation solution was artificially contaminated with Staphylococcus aureus ATCC 12600. Following the surgery, staphylococci were detected in the operating room at an extension of 5x7 m. Everybody showed extensive face and body contamination with Staphylococcus aureus. The study showed that the use of high-speed cutters in surgery of the cervical spine produces an aerosol cloud that is spread over the whole surgical room and contaminates the theater and all personnel present. Such aerosols can be contaminated with pathogens if the patient was infected or colonized. Therefore, sufficient protective measures have to be recommended for everyone present in the operating room during such surgeries. In addition, efficient disinfection of the room and all mobile equipment is necessary after each surgery involving high-speed cutting devices.

Aerosols↗
PubMed2001

Footwear affects the behavior of low back muscles when jogging.

Use of modified shoes and insole materials has been widely advocated to treat low back symptoms from running impacts, although considerable uncertainty remains regarding the effects of these devices on the rate of shock transmission to the spine. This study investigated the effects of shoes and insole materials on a) the rate of shock transmission to the spine, b) the temporal response of spinal musculature to impact loading, and c) the time interval between peak lumbar acceleration and peak lumbar muscle response. It was hypothesised that shoes and inserts a) decrease the rate of shock transmission, b) decrease the low back muscle response time, and c) shorten the time interval between peak lumbar acceleration and peak lumbar muscle response. Twelve healthy subjects were tested while jogging barefoot (unshod) or wearing identical athletic shoes (shod). Either no material, semi-rigid (34 Shore A), or soft (9.5 Shore A) insole material covered the force plate in the barefoot conditions and was placed as insole when running shod. Ground reaction forces, acceleration at the third lumbar level, and erector spinae myoelectric activity were recorded simultaneously. The rate of shock transmission to the spine was greater (p < 0.0003) unshod (acceleration rate: Means +/- SD 127.35 +/- 87.23 g/s) than shod (49.84 +/- 33.98 g/s). The temporal response of spinal musculature following heel strike was significantly shorter (p < 0.023) unshod (0.038 +/- 0.021 s) than shod (0.047 +/- 0.036 s). The latency between acceleration peak (maximal external force) and muscle response peak (maximal internal force) was significantly (p < 0.021) longer unshod (0.0137 +/- 0.022s) than shod (0.004 +/- 0.040 s). These results suggest that one of the benefits of running shoes and insoles is improved temporal synchronization between potentially destabilizing external forces and stabilizing internal forces around the lumbar spine.

Acceleration↗
PubMed2001

Excessive heat generation during cutting of cement in the Robodoc hip-revision procedure.

The ROBODOC system is a promising new method for removing cement with high-speed milling. Heat is generated during the milling process. This study was designed to measure temperatures in the cutting area, and to assess the risk of heat injury and the effectiveness of irrigation. We measured temperatures at the bone-cement cutting area in three experimental settings, two involving the proximal area comprising a cement mantle, and one the distal cement plug beneath the prosthesis. Without cooling facilities, a mean temperature of 94 degrees C was measured in proximal areas. However, this could effectively be reduced below 70 degrees C with irrigation. In the area of the distal cement plug, we measured a mean temperature of 172 degrees C without irrigation. In this area, the integrated irrigation system with an additional high-flow irrigation system could not guarantee cooling to an acceptable temperature of below 70 degrees C since the irrigation stream was impeded by the cutter in the narrow cavity. We need an integrated irrigation device that guarantees continuous cooling at the cutting interface in front of the cutter.

Arthroplasty, Replacement, Hip↗
PubMed2001

Radiographic assessment in total knee arthroplasty.

Sixty-five total knee arthroplasties were evaluated by the Knee Society Radiological Evaluation System which was developed to encourage uniform reporting of the results of total knee arthroplasty. All patients were examined by three independent experienced radiologists 8.9 years after surgery (range, 3-16 years) to analyze the interobserver variability. For measurement of angles, high interobserver correlation was calculated for the prosthetic component angles and the femorotibial shaft angle. The comparison of the means indicated no significant differences except for the femorotibial shaft angle. For measurement of radiolucent lines, interobserver correlation was low for all components. The differences of the means were significantly different for all components. The results of interobserver variability of the patellar evaluation revealed high interobserver correlation for the patellar angle and for patellar subluxation and dislocation evaluation. For assessment of patellar mediolateral and superoinferior displacement, a low interobserver correlation was found. For radiographic assessment of total knee arthroplasty, the measurement of angles, including alpha, beta, femorotibial shaft angle, sagittal femoral and tibial component angle, patellar angle, and patellar subluxation and dislocation evaluation are recommended. The method of assessing radiolucent lines should be reconsidered.

Aged↗
PubMed2001

Fistula between a total hip arthroplasty and the rectum: a case report.

An 81-year-old man was referred to the authors for examination of the gastrointestinal tract. A proctoscopy revealed a draining sinus tract in the terminal rectum. Plain radiographs revealed a failed total hip arthroplasty that had migrated into the pelvis. Hip aspiration revealed an infection with bacteria commonly found in the gastrointestinal tract. A fistulogram confirmed a connection between the rectum and the hip replacement. The development of a fistula between the colon and the hip is extremely uncommon. A fistula between the hip and the rectum is a previously unreported complication of total hip arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2001

Radiologic abnormalities and low back pain in elite skiers.

Lumbar radiographs of 120 adolescent elite skiers were evaluated for radiologic abnormalities by two independent observers. All athletes had no symptoms before the study. Radiographs were taken before enrollment of the students in elite level training. To determine the clinical significance of these abnormalities, all athletes were observed prospectively during the subsequent 2-year period for development of low back pain under high performance training. Anterior end plate lesions, Schmorl's nodes, posterior end plate lesions, spondylolysis, scoliosis, and spina bifida occulta were found. The depth of anterior end plate lesions showed a two-peak distribution, with peaks at 11% and 22% and a valley at 18% vertebral body height. The overall low back pain incidence was 12.5%. Students with severe anterior lesions (greater than 18% vertebral body height, n = 25) had significantly more low back pain (incidence, 32%) than did students without severe anterior lesions (incidence, 7.4%). Accordingly, students with severe anterior lesions had a significantly higher risk of having low back pain develop. Moderate end plate lesions and other abnormalities were not related to an increased incidence of low back pain. Adolescent students of elite sports with severe lumbar anterior end plate lesions have an increased risk of having low back pain develop under high performance training.

Adolescent↗
PubMed2000

False aneurysm 14 years after total hip arthroplasty.

Many reports of complications after total hip arthroplasty have been published concerning typical orthopaedic problems. Relatively little attention has been paid to serious vascular injuries, such as the development of a false aneurysm. To our knowledge, 10 cases have been described in the English literature. The mean time interval between surgery and initial manifestation of the aneurysm was 9 months in these cases. Our patient developed first symptoms of a false aneurysm 14 years after surgery. A minimally invasive technique was used to cut the aneurysm from perfusion. Removal of the total hip arthroplasty was performed through a retroperitoneal and lateral approach.

Aged↗
PubMed2000

Glenohumeral osteoarthrosis after the Eden-Hybbinette procedure.

Thirty-six patients (36 shoulders) who underwent the Eden-Hybbinette procedure for recurrent anterior dislocation of the shoulder with an average followup of 15 years were evaluated. Evaluation consisted of radiographic assessment in a true anteroposterior view and an axillary lateral view of both shoulders, physical examination, and a questionnaire. Mild glenohumeral osteoarthrosis was present in 1/3 of the patients, and moderate and severe osteoarthrosis was evident in 1/2. There were no signs of osteoarthrosis in four shoulders. Function, as assessed by the Rowe score as modified by Young and Rockwood, was excellent or good in 27 shoulders and fair or poor in nine shoulders. The extent of osteoarthrosis was related to restriction of external rotation, length of followup, and function.

Adolescent↗
PubMed1999

Autogenic versus allogenic bone grafts in anterior lumbar interbody fusion.

Between 1987 and 1993, 94 consecutive patients with painful spondylolisthesis underwent combined anterior and posterior fusion. The average age at operation was 40 years (range, 16-65 years). Posterior fusion was performed in all patients using pedicle screw systems, and anterior fusion was accomplished with autogenic or allogenic bone grafts. Patients retrospectively were assigned to two groups. In Group 1, anterior fusion was performed with autogenic bone grafts harvested from the iliac crest (n = 65; 146 segments) and in Group 2 allogenic bone grafts were taken from femoral heads (n = 39; 86 segments). The incidence of pseudarthrosis was evaluated on lateral tomograms 24 months after surgery. The mean clinical followup time was 4 years (range, 3-8 years). Pseudarthrosis was found in seven fused levels (3%) managed with autogenic bone grafts (Group 1) and in seven patients (8%) managed with allogenic bone grafts (Group 2). This incidence of pseudarthrosis was not significantly different between the two groups. Considering the possible complications associated with harvesting iliac crest bone, the use of allogenic bone appears justified.

Adolescent↗
PubMed1999

Does arch height affect impact loading at the lower back level in running?

The purpose of this study was to evaluate the influence of the medial longitudinal arch height on the shock wave that repetitively reaches the lower back in running. Impact forces were measured simultaneously at the ground by a force plate and at the level of the low back, by means of an accelerometer, skin-mounted at the L3 spinal process. The medial longitudinal arch height was calculated as navicular height divided by foot length. Twelve healthy subjects ran barefoot and with an identical sport shoe at a constant speed. The sample size was divided equally into a low-arch and a high-arch group. Statistical analysis was performed by multivariate analysis of variance and Pearson's correlation. At low back level, there was a significantly lower acceleration amplitude and rate in the high-arch group (amplitude = mean, 1.74 g and SD, 0.94 g; rate = mean, 71.2 g/sec and SD, 58.0 g/sec) compared with the low-arch group (amplitude = mean 2.25 g and SD, 1.11 g; rate = mean, 111.5 g/sec and SD, 68.6 g/sec) (P < 0.001, each). At the ground, there was a slight negative correlation between arch height and initial loading rate in AP (-0.19; P < 0.01) and vertical (-0.22; P < 0.001) directions and a positive correlation between arch height and initial loading rate in the medial direction (0.22, P < 0.05). The results indicate that the high-arch foot is a better shock absorber with regard to the low back level than the low-arch foot.

Adult↗
PubMed1998

The impact of stressful life events on exacerbation of chronic low-back pain.

The impact of stressful life events on the development and onset of chronicity of low-back pain is not yet fully understood. Sixty-four consecutive patients with chronic low-back pain treated at the orthopedic out-patient unit of the Innsbruck University Hospital were investigated with regard to stressful life events. Patients were classified into two groups: one group consisting of patients whose pain had an organic etiology (n= 16), and another group consisting of those with pain of uncertain origin (idiopathic group, n=48). A method combining a semistructured interview with a self-assessment of the severity of stress caused by life events was employed for assessing the impact of such events on chronic low-back pain. In comparison to the patient group having organic causes of pain, the idiopathic group showed significantly more patients having at least one highly stressful event preceding the last substantial aggravation of pain (p=0.028). The latter group experienced significantly more exhaustion (p=0.016) and significantly more difficulties in active coping (p=0.011) when confronted with stressful life events. Stressful life events that arouse feelings of helplessness may contribute to the development of chronic idiopathic low-back pain. Our results emphasize the importance of investigating the subjective meaning and appraisal of stressful life events, taking into consideration both individual predisposition and psychosocial resources available to the patient. Finally, it is also important that the attending physician be aware of any life event that is particularly stressful for the patient so that psychosocial help be made available at the appropriate time.

Adult↗
PubMed1998

Predisposing factors for infection in spine surgery: a survey of 850 spinal procedures.

A retrospective survey of 850 spinal procedures was conducted to determine risk factors for postoperative spinal infection. Some 574 posterior and 276 anterior procedures were evaluated. Infections were classed as early (within 19 weeks postoperatively) and late (> or = 20 weeks postoperatively), as well as deep and superficial infections. Previously postulated risk factors (i.e., diabetes, corticosteroid therapy, previous spinal surgery, obesity, chronic infection, and smoking) were investigated. Furthermore, it was hypothesized that three additional factors: extended preoperative hospitalization, prolonged operation duration, and high blood loss were risk factors not previously considered. A postoperative infection was evident in 22 of 850 procedures (19 early/three late infections, four superficial/18 deep infections). Most infections (n = 21) occurred with posterior instrumentation. Previously described factors were proven as risk factors. Extended preoperative hospitalization (p < 0.04), high blood loss (p < 0.01), and prolonged operation time (p < 0.001) were additionally determined as risk factors. The results suggest that routine prophylactic antibiotics might be unnecessary in anterior surgery, whereas extended prophylactics should be considered in posterior instrumentation, especially when risk factors are apparent.

Adolescent↗