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Biomedical subjects

W Schlickewei

Publications and source records attributed to W Schlickewei.

At least 19 recordsLinked to original sources

Injury reduction by the airbag in accidents.

Today an increasing number of automobiles are being equipped with additional passive safety devices: driver and passenger airbags. To examine the efficiency of the airbag in real road traffic accidents, a collective study was conducted from 181 traumatology centres throughout Germany. The inquiry was answered by 81 per cent of the medical centres contacted. From the evaluation of 122 accident victims in 1993 who were protected with an airbag the following was concluded. The patients treated in surgical and in traumatological departments suffered predominantly superficial injuries of the head, cervical vertebra and thorax. Some of these chiefly superficial wounds, such as abrasions and bruises, were initiated by contact with the airbag. It is remarkable that 72.1 per cent of the airbag-protected patients suffered a maximum of MAIS 2. What is also notable is the continuing high number of patients suffering from severe injuries (AIS 3+) of the lower extremities.

Abbreviated Injury Scale

[Pelvic fractures: epidemiology, therapy and long-term outcome. Overview of the multicenter study of the Pelvis Study Group].

Pelvic fractures are rare injuries (3-8%) when compared to fractures in other body regions. They are accompanied by high mortality (5-20%), and the survivors suffer from severe pain and pelvic-related handicaps. The German Pelvic Group (German Chapter of the AO-International & German Trauma Society) started a prospective multicenter study, including ten major trauma centers for collecting a high number of data in a short period of time (1991-1993). All pelvic injuries were documented consecutively using a special set of evaluation sheets. The study closed with 1,722 patients. A 2-year follow-up was completed for 486 patients injured in 1991 and 1992 after type B and C injuries, complex pelvic trauma, acetabulum fractures and a random 25% of A-type injuries (overall follow-up rate 73%). The follow-up included special "out-come" criteria. Of the pelvic ring injuries without significant peripelvic soft tissue involvement, 63.6% were A-type fractures, 21.0% B-type injuries and 15.5% C-type injuries. The rate of operative stabilization was 3.9% after A-type injuries, 37.3% after B-type injuries and 54.3% after C-type injuries. In isolated acetabular fractures ORIF was performed in 38.6%. The total lethality was 7.9% with a significant difference between "complex" pelvic trauma (21.3%) and patients without concomitant peripelvic injuries (7.2%). In 0.9% the pelvic injury was reported as the main cause of death. Pain at follow-up was observed in every classification group, the rate of completely "pain-free" patients being 55% after A-type, 41% after B-type and 27% after C-type fractures. Malfunction of micturia was reported by 7.6% of all patients, sexual malfunction by 11.6% of the males ("erectile dysfunction") and 2.2% of the female ("dysparneuria"). Scaled by the recently developed "outcome score", the radiological result showed anatomical healing after 90.8% of the B-type and 74.6% of the C-type injuries. On the other hand, the clinical result was rated as good or excellent in only 70% of the B-type and 54% of the C-type injuries. Although progress in indications and treatment techniques has shown improved radiological results after unstable pelvic ring injuries when compared to earlier studies, the clinical result still remains unsatisfactory. Further analyses and studies must be conducted to identify the prognostic factors for the late sequelae. Whether it is possible influence these factors by additional surgical intervention cannot be answered at present.

Acetabulum

[Reconstruction of open width of the spinal canal by internal fixator instrumentation and remodeling].

In 106 cases of unstable vertebral fractures treated with the ASIF internal fixator, the degree of restoration of the spinal canal could be studied in detail. Computer-aided planimetry was used to measure the area of the spinal canal. Three series could be studied, where the postoperative CT scans had been performed at different times. The first series of 58 cases had the CT scans taken immediately after surgery; the initial mean traumatic narrowing of the spinal canal had been 42.8%, but after surgery it was only 25.2%. The second series consisted of 74 CT scans performed after implant removal. At this time, a residual defect of only 3.7% was observed. In a third series 31 cases could be analysed where CT scans obtained both directly after surgery and after implant removal were available. This confirmed the first two series insofar as it demonstrated the existence of a further mechanism, i.e. remodeling, that served to increase the degree of restoration of the spinal canal. This biological-functional process operates to approximately the same degree at each fracture level, demonstrated by the almost parallel course of the graph showing reduction plus internal fixation and remodeling. In summary, the remaining deficit of 25% after surgery is restored almost to normal through remodeling and can be neglected, provided there is no neurologic damage.

Adolescent

[Protective air bags in traffic accidents. Change in the injury pattern and reduction in the severity of injuries].

The effectiveness of air bags, drivers-side and passenger-side, as an additional passive safety system in motor vehicles was tested in a collective study in which 47 trauma centers in Germany participated. The inquiry was answered by 80% of 181 hospitals. The evaluation of a total of 119 air bag-protected patients involved in accidents, who were treated in German trauma centers in the year 1993 shows predominant minor injuries on the head-, cervical- and thorax-region. Some patients had superficial injuries caused by air bag in their face and chest area, such as abrasions and contusions. It is notable, that a large number of patients continue to suffer severe injuries (AIS 3+) in their lower extremities. The trend of the industry to equip more and more vehicles with air bags must be sustained. According to manufacturer statements, in 1994 already more than 60% of all mass produced vehicles in Germany will be provided with this modern passive safety system.

Abdominal Injuries

Ligamentotaxis with an internal spinal fixator for thoracolumbar fractures.

We assessed narrowing of the spinal canal in 39 burst fractures and fracture-dislocations of thoracolumbar vertebrae treated by the AO Internal Spinal Fixator, using CT preoperatively and at various stages postoperatively. Computer-aided planimetry was used to measure the narrowing, and its restoration shortly after instrumentation, or at 15 months. The mean initial reduction of canal area was to 63.7% +/- 18.8% of normal; this was restored to a mean of 95.4% +/- 21.2% of normal when measured either soon after surgery or at 15 months (p < 0.001 for both groups). There was more improvement in cases assessed later. For fractures from D12 to L3, the mean canal area was restored to 99.4% of normal; but at L4 or L5 the mean restitution was to only 60.9% (p < 0.05). We found no correlation between preoperative loss of area and amount of restoration, or severity of neurological deficit. Nor was there any correlation between the delay before surgery and the improvement achieved. The mechanism of fracture reduction appears to be a combination of distraction ligamentotaxis and forced hyperextension.

Adolescent

Influence of humate on calcium hydroxyapatite implants.

Implanted bovine apatite is highly osteoconductive, since it serves the host tissue as a "guide-line" for the deposition of newly developing bone tissue. It is well tolerated, but it showed no signs of being resorbed during the course of the experiment. Previous impregnation of the bovine hydroxyapatite with a low molecular humate substance obviously encourages its resorption. This is most easily explained by the known ability of humate to induce the activation of leucocytes. The occasional over-resorption of the apatite is dependent (1) upon the preparation of the implant (granulate) and (2) the local concentration of the humate. Future research is being directed towards the production of a satisfactorily usable form of humate and apatite and the investigation of its HIV blocking action on heterologous cancellous bone.

Animals

Hip dislocation without fracture: traction or mobilization after reduction?

In all, 41 patients with traumatic dislocation of the hip, without associated acetabular or femoral fracture, were treated by two different methods after closed reduction, performed on average 2 h after injury. Patients in group A (N = 20) were subjected to skeletal traction for 2 weeks, followed by non-weight bearing for 3 months. Those in group B (N = 21) were mobilized a few days (average 9 days) after injury and allowed partial weight bearing. They were fully weight bearing at 3 months. The 31 patients were followed up for an average of 7.6 years and showed comparable long-term results in both groups. No early complications occurred in group B. There were no cases of avascular necrosis in either group. There were three cases of post-traumatic arthritis in group A and one in group B, and two cases each of heterotopic ossification. Early mobilization was concluded to be a safe and more comfortable method of after-treatment. Earlier return to work was a significant benefit in Group B.

Adolescent

[Metal abrasion as an imaging artefact in nuclear spin tomography].

Eighteen patients with vertebral body fractures that had been stabilized by an internal spinal skeletal fixation system were prospectively examined by magnetic resonance (MR) imaging between February 1989 and November 1990 at the Department od Diagnostic Radiology of the University Hospital Freiburg 3-7 days after removal of the metallic implants. In most cases imaging artifacts in the paraspinal extensor muscles were evident on MR studies. These were found especially in the region of the previous site of the metal clip jaw bearing. In a few cases artifacts were also present within the vertebral body and/or vertebral arch, but only if the vertebral body had been surgically reconstructed by transpedicular spongiosa implantation. None or only minor artifacts by abrasion of metal were detected if the (modified Schanz's) screws appeared to be tight at surgical removal of the implants. Therefore, marked metal artifacts on MR imaging retrospectively indicate a chronic straining of the implants, which has been shown to be a risk factor for implant loosening. Additional in vitro studies with powdered metallic alloy showed that as little as 1 mg of metal could be detected as artifacts in routine spin-echo sequences. When the metallic pieces were large enough to be seen on conventional radiographs or computed tomograms, they caused severe, distorting artifacts on MR imaging. It is concluded that MR imaging is the method of choice for detection of small amounts of metal.

Adult