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Biomedical subjects

M Krismer

Publications and source records attributed to M Krismer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Pelvic tilt in neuromuscular disorders.

The pelvic tilt is part of a complex deformity in which both the spine and the hip are involved. By viewing the different planes and analyzing the deforming forces, four different types of pelvic tilt in combination with spinal and hip deformities can be identified. In spina bifida patients congenital deformities of the spine may add to the progression of scoliosis. Analyzing our own patients we found that certain types of pelvic tilt can be related to certain neuromuscular diseases. Moreover our results show that the pelvic tilt can be effectively corrected by spinal surgery, whereas no effect of hip surgery could be demonstrated.

Cerebral Palsy↗
PubMed2000

Comparison of migration in modular sockets with ceramic and polyethylene inlays.

This study compared migration in 73 cementless total hip arthroplasties (THAs) with either alumina ceramic (n = 23) or polyethylene (n = 50) inlays; prosthesis sockets and stems were identical except for the inlays. After 7 years of follow-up, 5 sockets (4 with ceramic and 1 with polyethylene inlays) had been revised an average of 63.3 months (range: 49-81 months) after implantation, and survival analysis showed a significantly higher revision rate for sockets with ceramic inlays (89 +/- 6%) versus polyethylene inlays (98.2 +/- 1.7%) (P = .032). Migration analysis of the first three postoperative years revealed significantly higher vertical migration in sockets with ceramic inlays (P = .047), in patients aged <60 years (P = .02), and in osteoporotic type C bone (A versus C, P = .0071 and B versus C, P = .0004).

Ceramics↗
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

Migration of the Duraloc cup at two years.

We carried out 71 primary total hip arthroplasties using porous-coated, hemispherical press-fit Duraloc '100 Series' cups in 68 consecutive patients; 61 were combined with the cementless Spotorno stem and ten with the cemented Lubinus SP II stem. Under-reaming of 2 mm achieved a press-fit. Of the 71 hips, 69 (97.1%) were followed up after a mean of 2.4 years. Migration analysis was performed by the Ein Bild Rontgen Analyse method, with an accuracy of 1 mm. The mean total migration after 24 months was 1.13 mm. Using the definition of loosening as a total migration of 1 mm, it follows that 30 out of 63 cups (48%) were loose at 24 months.

Adult↗
PubMed1999

The prediction of failure of the stem in THR by measurement of early migration using EBRA-FCA. Einzel-Bild-Roentgen-Analyse-femoral component analysis.

We report the ten-year results for three designs of stem in 240 total hip replacements, for which subsidence had been measured on plain radiographs at regular intervals. Accurate migration patterns could be determined by the method of Einzel-Bild-Roentgen-Analyse-femoral component analysis (EBRA-FCA) for 158 hips (66%). Of these, 108 stems (68%) remained stable throughout, and five (3%) started to migrate after a median of 54 months. Initial migration of at least 1 mm was seen in 45 stems (29%) during the first two years, but these then became stable. We revised 17 stems for aseptic loosening, and 12 for other reasons. Revision for aseptic loosening could be predicted by EBRA-FCA with a sensitivity of 69%, a specificity of 80%, and an accuracy of 79% by the use of a threshold of subsidence of 1.5 mm during the first two years. Similar observations over a five-year period allowed the long-term outcome to be predicted with an accuracy of 91%. We discuss the importance of four different patterns of subsidence and confirm that the early measurement of migration by a reasonably accurate method can help to predict long-term outcome. Such methods should be used to evaluate new and modified designs of prosthesis.

Acetabulum↗
PubMed1999

Accuracy of EBRA-FCA in the measurement of migration of femoral components of total hip replacement. Einzel-Bild-Röntgen-Analyse-femoral component analysis.

Several methods of measuring the migration of the femoral component after total hip replacement have been described, but they use different reference lines, and have differing accuracies, some unproven. Statistical comparison of different studies is rarely possible. We report a study of the EBRA-FCA method (femoral component analysis using Einzel-Bild-Röntgen-Analyse) to determine its accuracy using three independent assessments, including a direct comparison with the results of roentgen stereophotogrammetric analysis (RSA). The accuracy of EBRA-FCA was better than +/- 1.5 mm (95% percentile) with a Cronbach's coefficient alpha for interobserver reliability of 0.84; a very good result. The method had a specificity of 100% and a sensitivity of 78% compared with RSA for the detection of migration of over 1 mm. This is accurate enough to assess the stability of a prosthesis within a relatively limited period. The best reference line for downward migration is between the greater trochanter and the shoulder of the stem, as confirmed by two experimental analyses and a computer-assisted design.

Acetabulum↗
PubMed1999

Measurement of vertebral rotation: a comparison of two methods based on CT scans.

This study compared Ho's and Aaro's method to measure vertebral axial rotation in order to find the more accurate one. Two hundred fifty-nine CT scans were taken from 11 cadaver vertebrae. The scans were performed with vertebrae in neutral position and angulated up to 20 degrees in the sagittal and frontal plane to simulate kyphosis/lordosis and side bending. Axial rotation was measured according to both methods. The mean difference between true and measured values was 3.7 +/- 6.7 (95% confidence limit) (Ho's method) and 2.3 +/- 3.7 (Aaro's method), respectively. Correlation with true axial rotation was r2 = 0.66 (Ho's method) and r2 = 0.77 (Aaro's method). We recommend using Aaro's method as the more accurate measure of axial rotation in scoliotic vertebrae.

Cadaver↗
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

Different cup migration in rheumatoid arthritis and arthrosis: a radiographic analysis of 127 uncemented acetabular cups.

We compared retrospectively the radiographic migration profiles of 82 acetabular components in 61 patients having rheumatoid arthritis with those of 45 hips having arthrosis who underwent a standardized technique of cementless arthroplasty with the Zweymüller prosthesis (Alloclassic). We used a modification of Dickob's technique of digital migration analysis that corrects for magnification errors and horizontal pelvic tilt. The rheumatoid patients were stratified as having oligoarticular, polyarticular, or mutilating arthritis. The overall rate of acetabular loosening in rheumatoid hips after mean 88 (26-117) months was 4%. Loosening was seen only in cases with mutilating arthritis and acetabular protrusion, where the direction of cup migration was also clearly different from that detected in the other types of rheumatoid arthritis and in arthrosis. The different patterns of cup migration in cementless hip replacement for rheumatoid arthritis, depending on disease severity, is of importance when comparing outcome of total hip arthroplasty in rheumatoid patients.

Adult↗
PubMed1998

Comparison of spinal mobility after Harrington and CD instrumentation.

Of 229 patients, 15 pairs of patients with right thoracic idiopathic scoliosis (King III) and 15 pairs with combined thoracic and lumbar scoliosis (King II) were identified. Each pair consisted of one patient with Harrington and the other with Cotrel-Dubousset instrumentation. Pairs were comparable with regard to thoracic curve magnitude, and level of end and stable vertebrae. Minimum follow-up was 4 years postoperatively. Spinal mobility of patients in the coronal and sagittal plane, and axial rotation was measured with inclinometers. The differences between operatively treated groups are not significant. The more caudal instrumentation ends, the more reduced is spinal mobility in the coronal plane. Motion in operated patients is significantly reduced in comparison to a healthy reference group.

Adolescent↗
PubMed1997

Surgical treatment of neuropathic scoliosis: morphologic and functional outcome.

We evaluated the morphologic and functional outcome as well as the extent of satisfaction following surgical treatment in 41 patients with progressive neuropathic scoliosis. The mean follow-up time was 5.6 years (range 2.5-20 years), and follow-up rate was 97.6%. Posterior spine fusion was performed with new instrumentation techniques (Luque/Luque-Galveston, CD, ISOLA) in 29 patients, with extension onto the sacrum in 16 patients, and Harrington instrumentation in 12. In 20 patients we did an additional intervertebral disc excision and fusion. Mean correction of the thoracic spine deformity, as assessed by comparing the Cobb angles on pre- and postoperative X-rays, was 53%, and of the lumbar spine 55.2%, in patients classified as Lonstein I. Scolioses classified as Lonstein II evidenced an average correction of 46.2%. Functional improvement according to the Rancho-Los Amigos scheme could be demonstrated in 20 patients. Seventeen patients remained unchanged, whereas 4 patients showed deterioration. Cosmetic results were rated as excellent by 25 patients, good by 7, and poor by 1. For 8 patients the appearance was unimportant. Pain relief was experienced in all cases (n = 4) of the preoperative low-back or abdominal pain. The major complications were deep wound infection in 3 patients which led to revision surgery, and removal of instrumentation in 1 patient.

Adolescent↗
PubMed1997

Results of the Müller acetabular reinforcement ring in revision arthroplasty.

Between April 1984 and December 1987 a Müller acetabular reinforcement ring was employed in 98 revision cases (94 patients). Twenty-two patients died before follow-up evaluation. Forty-seven (66%) of the remaining 72 patients (49 of 75 hips) were examined after a mean of 6.4 years (range 5-9 years). Excluding those who died, the postoperative outcome of 69 patients is known. Migration was measured according to Sutherland by means of a digitising table. Cup position was determined by a new angle (beta) between the sacroiliacal line and a reference line. The reference line connects the centre of the femoral head with the intersection between the sacroiliacal and obturator lines. Aseptic and septic loosening required revision surgery in 2 cases each (4%). The postoperative beta angle showed a high correlation with migration (P = 0.001) as well as with radiolucencies (P = 0.001). In cases which required further revision, beta amounted to 44 deg (craniolateral position), and in stable cases up to 60 deg. A lateral and cranial position of a Müller acetabular reinforcement ring leads to high loosening rates. The beta angle accurately describes cup position, and its postoperative value is highly predictive for loosening.

Acetabulum↗
PubMed1997

[Biomechanics of lumbar instability].

Several authors have tried to define segmental lumbar instability. Their definitions: increased antero-posterior translation, pathologic coupled motion, increased neutral zone, pathologic instantaneous center of rotation describe some mechanic findings occurring in the aging spine. However, there is no evidence that they help to differentiate the pathologic entity of segmental lumbar instability from the normal aging process. Dynamic explanation models are promising but at the moment they cannot be used clinically for diagnosis of instability as well. The most important structure to maintain lumbar stability is the intervertebral disc. In the third and fourth decade, more than 50 percent of specimen show peripheral tears of the anulus. It was shown in animal experiments that these tears develop to radial tears, which are accompanied by nuclear volume loss and decreased height. The facets degenerate one or two decades later. Corresponding with the loss of discal function, they increasingly contribute to spinal stability. In conclusion, the concept of lumbar segmental instability is not very helpful in clinical practise. It is recommended to base the decision of lumbar fusion on a painful degenerated disc, and additional findings promising a good result.

Animals↗
PubMed1997

[Minimally invasive approach and surgical procedures in the lumbar spine].

The history of minimally invasive lumbar spine surgery began in 1963 with the introduction of chemonucleolysis. Like this technique, the later development of mechanical nucleotomy and lasernucleotomy aimed primarily at reduction of the disc pressure. Miniature optical systems offered the opportunity for more specific decompression by discoscopy or, more recently, by transforaminal epiduroscopy. Initially, nucleotomy was the only feasible minimally invasive procedure. In recent years, however, minimally invasive spinal fusion became possible due to the development of new devices (Cages) and advanced transperitoneal (laparoscopic) and retroperitoneal approaches.

Decompression, Surgical↗
PubMed1997

[Single-image roentgen analysis for the measurement of hip endoprosthesis migration].

A method to determine migration of hip endoprostheses is described. Migration is measured by means of standard AP radiographs and therefore can also be evaluated in retrospective studies. Measurement is conducted in X-ray studies displayed on a computer screen. Enhancement of bony structures by application of filters is available. The developed software can be used with common commercially available computers and X-ray scanners, and does not require special hardware. Several methods to determine accuracy are described. The accuracy of the described method is about 1 mm (95% confidence limit), which compares favourably with other methods, but is less accurate than roentgen stereophotogrammetry. For other methods, accuracy was not determined adequately. Two years after implantation, revision within the first 10 years of follow-up can be predicted with a sensitivity and specificity of more than 80%.

Acetabulum↗