PubMed Health⌕ Search

Biomedical subjects

M Krismer

Publications and source records attributed to M Krismer.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Advantages and disadvantages of retro- and transperitoneal approach for fusion of the presacral intervertebral disk].

In a retrospective study, we evaluated 180 patients treated for painful spondylolisthesis with combined anterior and posterior fusion. Group I included 90 patients treated by anterior fusion with the transperitoneal approach. Group II included 90 patients operated on with a retroperitoneal approach. Group II showed a higher incidence of pseudarthrosis L5/S1 (4%), tear of the common iliac vein (1%), postsympathectomy syndrome (4%) and reversible L4 nerve-root lesion (3%). On the basis of our findings, we recommend the transperitoneal approach for anterior interbody fusion L5 to S1 or L4 to S1.

Adolescent↗
PubMed1997

[Lumbar fusion in adults--dorsal or combined ventral/dorsal approach?].

A retrospective study was conducted to compare the results of posterior with combined anterior/posterior lumbar fusion in adults. Seventy-six consecutive posterior cases fused with pedicle screws and 46 combined cases were included and followed for at least 2 years. Subjective assessment was based on the Visual Analogue Scales, Waddel Disability and Impairment Score and the GBB for objective quantification of complaints. Furthermore, a thorough clinical examination was done and X-rays including flexion/ extension radiographs, were taken. Questions were asked about the occupational status as well. Pain decreased significantly more in the combined cases than in the posterior fusion cases. In one case a lesion of the common iliac vein occurred during a retroperitoneal approach. Only about half the patients working preoperatively returned to work again. In conclusion, the benefit of better pain relief after combined fusion must be regarded in relation to a higher complication rate due to a second approach.

Adult↗
PubMed1997

AP-translation in the proximal disc adjacent to lumbar spine fusion. A retrospective comparison of mono- and polysegmental fusion in 120 patients.

120 consecutive patients with painful spondylolisthesis underwent combined anterior and posterior fusion. Patients were divided retrospectively into two groups. In group I, 46 patients were treated with monosegmental fusion. In group II, 74 had polysegmental fusion. The mean follow-up time was 3 (2-7) years. Anterior posterior (AP)-translation in the first disc superior to fusion was measured according to Wiltse and Winter (1983). In group I, 3 and in group II, 10 patients developed an AP-translation of more then 3 mm in the disc adjacent to the fusion. AP-translation correlated with the number of fused segments and the follow-up time.

Adolescent↗
PubMed1996

Comparison between single-screw and triangulated, double-screw fixation in anterior spine surgery. A biomechanical test.

STUDY DESIGN: The advantage to fixation strength of triangulated, double-screw fixation compared with that of single-screw instrumentation in anterior spine surgery was evaluated by in vitro testing. OBJECTIVES: To compare the fixation strength of single-screw instrumentation with ventral derotation spondylodesis screws with the fixation strength of triangulated, double-screw instrumentation with Cotrel-Dubousset-Hopf screws. Resistance against pull-out load and against load perpendicular to the axis of the screws was evaluated. To avoid the bias caused by different screw design, the pull-out strength of single screws of both devices was compared first. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, no study comparing anterior single with triangulated screws has been published. METHODS: A pull-out test was performed when one vertebra in each spine specimen was instrumented with a ventral derotation spondylodesis screw, one with an isolated Cotrel-Dubousset-Hopf screws, and one with two triangulated, Cotrel-Dubousset-Hopf screws linked by a Cotrel-Dubousset-Hopf block. Load perpendicular to the axis of the screw was applied on the bone-device interface after instrumentation of further specimens with ventral derotation spondylodesis and triangulated, Cotrel-Dubousset-Hopf devices. RESULTS: Use of isolated Cotrel-Dubousset-Hopf screws compared with ventral derotation spondylodesis screws showed no significant differences in pull-out strength. The use of triangulated, double-screw fixation with Cotrel-Dubousset-Hopf screws led to a significant 79% increase in resistance against pull-out and a 73% increase in resistance against load perpendicular to the screw axis compared with the resistance produced using ventral derotation spondylodesis single-screw instrumentation. CONCLUSION: In anterior surgery, fixation of the vertebra-device interface can be improved considerably by application of two triangulated screws.

Aged↗
PubMed1996

The contribution of anulus fibers to torque resistance.

STUDY DESIGN: Anulus fibers of the intervertebral disc oriented in one direction were dissected, and oppositely directed fibers were left intact as a result of a newly developed dissection method. Motion segments were dissected by this way, and motion segments after bilateral facetectomy were loaded in torsion and compared with each other. OBJECTIVES: To assess the contribution of facets and anulus fibers to torque resistance. SUMMARY OF BACKGROUND DATA: Mathematical models predict that torsional stress is transmitted only to those collagene fibers of the anulus that are angled in the direction of the applied torque. Torsion and forward bending or torsion and compression are likely to cause anulus damage. No experimental study that we are aware of has confirmed that anulus fibers are the main structure to resist against torque. METHODS: Pure axial rotation moments were applied on 12 lumbar motion segments. The six components of motion were recorded. Six motion segments were investigated intact after dissection of anulus fibers directed in one direction and after additional bilateral facetectomy. In six motion segments, bilateral facetectomy was performed before anulus dissection. RESULTS: With the application of an axial rotation moment of 8.5 Nm to the left, axial rotation increased 2 degrees after dissection of disc fibers in one direction, and 1.2 degrees after bilateral facetectomy (P = 0.002). In the opposite direction, there were no differences. After both injuries, axial rotation was 7.6 degrees to the left (direction of fiber dissection) and -3.3 degrees to the right (P = 0.0005). CONCLUSION: In lumbar motion segments without degeneration, anulus fibers restrict axial rotation more than the facets.

Adult↗
PubMed1996

Biomechanical properties of the human tibia: fracture behavior and morphology.

Standardized biomechanical dynamic load tests were performed to obtain fundamental information on the fracture behavior and morphology of the human tibia. After preparation, the specimens (n = 32) were loaded to breakage by ventral (one side alternately), dorsal, medial or lateral loading on a servo-hydraulic testing machine (Walter und Bai, Löhningen, Switzerland). Primary and secondary fracture lines and fissures were marked differently on the three surfaces of the tibia specimens. They were then videoscanned and digitized on a flatbed scanner to give two-dimensional fracture-line images. Load limits were 2475 to 12,206 Newton. The study revealed both direct fracture patterns with the fracture lines originating from the opposite site of impact, and indirect fracture patterns originating from the distal third of the specimens. Direct fractures occurred in 46% of the specimens after ventral loading, in 80% after medial or lateral loading, and in 100% after dorsal loading. Ventral, medial or lateral loading frequently produced direct wedge fractures of the Messerer type. Dorsal loading resulted in different direct patterns characterized by transverse fractures with longitudinal fissures at the impact site of the loading stamp. Direct transverse fractures also often showed a wedge-shaped pattern due to additional fissures. These were, however, identifiable only after maceration of the specimens and should receive closer attention in forensic practice.

Adolescent↗
PubMed1996

The possibility of creating lordosis and correcting scoliosis simultaneously after partial disc removal. Balance lines of lumbar motion segments.

STUDY DESIGN: The feasibility of correcting scoliosis and creating lordosis simultaneously in the thoracolumbar and lumbar spine by anterior instrumentation was investigated by in vitro testing. OBJECTIVES: To evaluate the vertebral zones in which a compressive load applied in a motion segment creates side bending and lordosis in intact motion segments and after partial disc removal. SUMMARY OF BACKGROUND DATA: Most investigators have observed a kyphogenic effect of anterior scoliosis instrumentation and recommended dorsal placement of screws and the use of wedge grafts, although wedge grafts were not used routinely by all surgeons. METHODS: Zones of lordosization and side bending were determined by evaluation of balance lines between extension-flexion and side bending, respectively, by axial loading on ligamentous human motion segments with intact discs and after partial disc removal. RESULTS: In lumbar motion segments with intact discs, it is possible to achieve ipsilateral side bending and lordosization by anterior instrumentation. After partial disc removal, the balance line between extension and flexion runs through the ipsilateral pedicle, and, therefore, a compressive load between the vertebral bodies always creates kyphosis. CONCLUSIONS: After partial disc removal, it is not possible to create lordosis and correction of scoliosis simultaneously by ipsilateral anterior instrumentation without the use of intervertebral wedge grafts.

Adult↗
PubMed1996

Axial rotation measurement of scoliotic vertebrae by means of computed tomography scans.

STUDY DESIGN: This study evaluated the preconditions for exact axial rotation measurement and the possibility for other parameters to measure axial rotation and mechanical torsion. OBJECTIVES: Quality criteria for axial rotation measurement in computed tomography scans are not established yet. Criteria should be found to improve axial rotation measurement. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, no systematic analysis of the errors of axial rotation measurement based on computed tomography scans has been performed. METHODS: Axial rotation was measured in 259 computed tomography scans of 11 cadaveric vertebrae from scoliotic specimens. The sagittal axial rotation measurement angle of Aaro and Dahlborn and a new rotation parameter were measured with a pencil and ruler. Five landmarks were digitized and consequently five axial rotation parameters were computed. The influence of insufficient visualization of bony landmarks, mechanical torsion of the vertebra itself, and oblique position of the vertebra was evaluated. RESULTS: Accuracy is considerably improved in central computed tomography scans (same distance to the top and bottom of the vertebral body) due to good visualization of landmarks and reduction of effects of mechanical torsion. The oblique vertebral position causes more errors. One mechanical torsion parameter with sufficient reliability is identified. CONCLUSION: The sagittal axial rotation measurement method of Aaro and Dahlborn is superior to other techniques of measurement. It can be improved considerably if computed tomography scans fulfill certain quality criteria.

Anthropometry↗
PubMed1996

The effect of ultrasonographic screening on the incidence of developmental dislocation of the hip.

The effect of ultrasonographic screening and treatment with a Pavlik harness on the incidence of developmental dislocation of the hip has been studied retrospectively. Observations were made at three different consecutive periods; in the first, clinical screening was carried out, in the second, ultrasonography was added for children up to 3 months of age, and in the third ultrasonography was used within the first few days of birth. A significantly decreased dislocation rate was demonstrated in each group, suggesting that early ultrasonography was of value in the early detection of dislocation.

Austria↗
PubMed1996

Early migration predicts late aseptic failure of hip sockets.

We report a prospective, stratified study of 60 PCA-cups and 60 RM-polyethylene cups which have been followed for a median time of 90 months, with annual radiography. The radiological migration of cups was measured by the computer-assisted EBRA method. A number of threshold migration rates from 1 mm in the first year to 1 mm in five years have been assessed and related to clinically determined revision rates. A total of 28 cups showed a total migration of 1 mm or more within the first two years; 13 of these cups have required revision and been exchanged. The survival curves of cups which had previously shown early migration were considerably different from those without early migration. For cups with a migration of less than 1 mm within the first two years the mean survival at 96 months was 0.96 +/- 0.02; for migrating cups, it was 0.63 +/- 0.11 (log-rank test, p=0.0001; chi-square value=39.4). Early migration is a good predictor for late loosening of hip sockets.

Aged↗
PubMed1995

EBRA: a method to measure migration of acetabular components.

In orthopedics there is a demand for determining migration of hip sockets by evaluation of standard radiographs. In this case problems are caused mainly by changing pelvis positions on the X-ray table at successive exposures. A method (EBRA) is described that evaluates standard AP radiographs without requiring additional means at exposure (e.g. ball markers). Simulating the spatial situation it computes parameters of longitudinal and transverse migration of prosthetic cup and femoral head. A comparability algorithm using a grid of transverse and longitudinal tangents of the pelvis contour divides serial radiographs into sets of comparable ones. Comparability of serial radiographs takes place if the distances of corresponding grid lines do not transcend a given limit L. Migration is measured only between comparable radiographs. Different studies are described concerning the interdependence of pelvis rotations and changes of the grid lines, the degree of pelvis rotations appearing in practice, the choice of the limit L, the properties of the comparability algorithm and the accuracy of EBRA. The 95% confidence limits for EBRA results are 1.0 mm for longitudinal and 0.8 mm for transverse migration.

Arthrography↗
PubMed1995

Recurrence of infection after revision of infected hip arthroplasties.

We performed revision surgery for infected arthroplasty in 98 hips (96 patients). In 28 hips infection persisted. Of the remaining 70 hips, 61 (87%) were reviewed after a mean interval of 5.9 years (1 to 17). Infection occurred in 10% of these after three years and in 26% after ten years. The infection rate after initially successful revision for septic arthroplasty is higher than after revision for aseptic loosening and the risk of developing infection continues for many years.

Aged↗
PubMed1994

A prospective study of the migration of two acetabular components. PCA versus RM cups.

Fifty-nine PCA cups and 61 hydroxyapatite-coated RM cups were included in a prospective randomised study with a mean follow up of 5.2 years. Clinical evaluation revealed better results with the RM cup. Radiological criteria of loosening could be applied only with considerable restrictions as different parameters were assessed: progressively loosened beads in PCA cups and faded contour in RM cups. Migration was measured by a computer assisted method (EBRA). PCA cups showed significantly more longitudinal migration 2 years after operation and subsequently. High migration values correlated with a limp. Loosening as defined by migration was of clinical relevance, could be measured early and predicted the survival rate.

Activities of Daily Living↗
PubMed1994

Acetabular development following early treatment of hip dysplasia by Pavlik harness.

One hundred sixty-two neonates with sonographically diagnosed developmental dysplasia of the hip (200 hips) according to the method of Graf were treated with a Pavlik harness until sonographic maturation was reached. Eight patients (12 hips) treated with closed reduction and retention in a bilateral hip spica cast were included. When the children started to walk their acetabular indices were assessed and demonstrated low-grade dysplasia in 26% and high-grade dysplasia in 6% according to the criteria of Tönnis and Brunken. We discuss the current sonographic criteria defining treatment-induced normalization and the adequacy of the length of treatment. We conclude that despite normal values at the end of treatment dysplasia may develop, which necessitates further radiological monitoring of all hips initially rated at risk on sonography. When to end monitoring, however, remains to be determined.

Acetabulum↗
PubMed1994

[The value of MRI in the preoperative assessment of scoliosis].

Clinical and radiological data of 48 patients with scoliosis who underwent routine MRI were reviewed to elicit the value of MRI in the preoperative assessment of complex spine deformities. Because of its high diagnostic sensitivity MRI gives a new insight into the true incidence of spinal cord pathology in scoliosis. Moreover, it identifies clinically unsuspected dysraphia in a surprisingly high percentage of neurologically asymptomatic patients with left-sided scoliosis. Exact planning of operative interventions is facilitated by the comprehensive diagnostic information gained through MRI. Furthermore, MRI generally allows one to refrain from invasive, high-irradiation techniques such as myelography and contrast-enhanced CT. On the basis of the presented investigational data, routine use of MRI is conclusively recommended in patients with congenital or idiopathic left-sided scoliosis.

Adolescent↗
PubMed1993

[Results of ultrasonographic screening. An epidemiological study].

The possible influence of early harness treatment for hip dysplasia--a treatment made possible by hip sonography according to Graf--on the incidence of hip luxations was examined in an epidemiological study. In a region with 8,000 births per year three periods were investigated: the pre-ultrasonographic era with 19 luxations per year (2.2/1000), the introductory era with 11 (1.3/1000) and the last period with 6 luxations so far (0.8/1000). A diagnosis can now be made at an earlier time due to the possibility of viewing the hip with sonography, a fact which significantly reduces the amount of hip luxations (pre-ultrasonographic era versus screening era: P = 0.00002), verified by the significant decrease in open and closed reductions.

Age Factors↗