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Biomedical subjects

L Kinzl

Publications and source records attributed to L Kinzl.

At least 37 records · Page 2Linked to original sources

[Operative results of treatment of intraarticular calcaneus fractures with the "low contact plate"].

Calcaneus fractures are a major cause of accident- related invalidity. Long-term results are unsatisfactory with various therapy concepts as reported in the literature. Objective of this study is the long-term clinical and radiological outcome of a patient group treated with a low contact plate. Subjective assessment of function by the patient was an important evaluation criterion. From 01/92 to 12/98 a total of 182 patients with 209 calcaneus fractures were treated. Out of them 95 patients with 109 calcaneus fractures had a follow-up over a period ranging from 6 to 88 months (average 37.9 months). Severe impairment of walking was reported by 34.7 % of the patients. Severe impairment for work was declared by 68.4 % of the patients. 74.7 % of the patients complained middle or severe burden-pain. 64.3 % of the patients felt their quality of life impaired. After the injury 75.8 % of the patients were still employed. Arthrosis of the inferior ankle joint was found in 91.5 % of the cases. Within this collective three patient groups were formed with different follow-up periods to evaluate the temporal course, showing no significant differences. Frequently good functional and subjective results cannot be expected even with standardized operative procedures.

Adolescent↗

Thoracolumbar fracture stabilization: comparative biomechanical evaluation of a new video-assisted implantable system.

Minimally invasive techniques for spinal surgery are becoming more widespread as improved technologies are developed. Stabilization plays an important role in fracture treatment, but appropriate instrumentation systems for endoscopic circumstances are lacking. Therefore a new thoracoscopically implantable stabilization system for thoracolumbar fracture treatment was developed and its biomechanical in vitro properties were compared. In a biomechanical in vitro study, burst fracture stabilization was simulated and anterior short fixation devices were tested under load with pure moments to evaluate the biomechanical stabilizing characteristics of the new system in comparison with a currently available system. With interbody graft and fixation the new system demonstrated higher stabilizing effects in flexion/extension and lateral bending and restored axial stability beyond the intact spine, as well as having comparable or improved effects compared with the current system. Because of this biomechanical characterization a clinical trial is warranted; the usefulness of the new system has already been demonstrated in 45 patients in our department and more than 300 cases in a multicenter study which is currently under way.

Biomechanical Phenomena↗

Relevance of primary reduction for the clinical outcome of femoral neck fractures treated with cancellous screws.

INTRODUCTION: Femoral head-preserving treatment for femoral neck fractures with cancellous screws is a method widely performed, but its success depends on the quality of primary reduction. The goal of our study was to evaluate the relevance of reduction quality on the clinical outcome. PATIENTS AND METHODS: We retrospectively analyzed the postoperative reduction result of 39 patients. The angular rotation and the inferior displacement of the proximal fracture fragment were digitally assessed from AP radiographs. The clinical outcome was recorded by a follow-up after a mean 5.5 years. RESULTS: Unsuccessful healing was observed in eight patients, femoral head necrosis in three patients, non-union in two patients, implant loosening in one patient, and posttraumatic arthritis in two patients, all resulting in the need for a total hip replacement. This clinical course was strongly associated with a primary reduction in varus position, whereas reduction in anatomic or valgus angulation had no negative effect on the clinical outcome. An inferior offset was no negative predictor for successful healing. CONCLUSION: We conclude that a non-anatomic reduction in varus angulation significantly increases the risk of healing failure and therefore should be avoided. Reduction in valgus position should be performed if secondary redislocation is imminent.

Adult↗

Influence of diclofenac (group of nonsteroidal anti-inflammatory drugs) on fracture healing.

INTRODUCTION: Nonsteroidal antirheumatics (NSAR; NSAID) are often used in patients with fractured bones for analgetic reasons. This animal experiment was performed to determine the influence of NSAR on the process of fracture healing. As an alternative, tramadol, the centrally acting analgetic without peripheral effects, was included in this experiment. MATERIALS AND METHODS: Wistar rats were operated on by a transverse osteotomy of the proximal tibia of the left leg. The fracture was stabilized by intramedullary nailing (healing period 21 days). All drugs were applied orally twice a day. The animals were divided into four groups with 10 rats each: Group 1 was treated with placebo (P), group 2 with tramadol (T; 20 mg/kg body weight/day), group 3 with diclofenac sodium (DS; 5 mg/kg bw/day) for 7 days followed by 14 days of placebo, group 4 with diclofenac sodium (DL; 5 mg/kgbw/day) over 21 days. On day 21 the rats were killed, and each leg was examined by X-ray, then the tibia was examined by CT scan, three-point bending, and histology. RESULTS: The results of CT and three-point bending showed that rats treated by diclofenac presented with delayed fracture healing compared with those treated by placebo or tramadol. Bone density in CT was highest in group 1 (mean 611.4+/-50.1 mg/ml), followed by group 2 (mean 542.5+/-29.5 mg/ml). Groups 3 (mean 411+/-34.0 mg/ml; p=0.006) and 4 (mean 395.2+/-15.4 mg/ml; p=0.009) were significantly lower. The stability of the bones, as measured by the breaking force ( F(max)), was highest in group 1 (mean 45.8+/-19.0 N), followed by group 2 (mean 39.0+/-7.9 N; NS); group 3 (mean 20.6+/-7.8 N; p=0.01) was significantly lower than the placebo animals, followed by group 4 (mean 26.5+/-8.3 N; p=0.03). Similar results were shown for bending stiffness: group 1 (mean 1404.6+/-611.4 Nmm/mm), group 2 (mean 1033.2+/-232.1 Nmm/mm; NS), group 3 (mean 564.2+/-457 Nmm/mm; p=0.045), and group 4 (mean 494.8+/-340.2 Nmm/mm; p=0.028). There were no significant differences between groups 1 and 2 and between groups 3 and 4, respectively. Diclofenac serum levels on day 21 in rats with long-term diclofenac application (mean 301.4+/-83.3 ng/ml) were comparable to those in humans. CONCLUSION: Oral application of diclofenac significantly delayed fracture healing in rats. This effect might be comparable to other NSAR and fracture healing in humans.

Analgesics, Opioid↗

[Prediction of mortality, mobility and admission to long-term care after hip fractures].

INTRODUCTION: Surgical treatment, discharge planning and rehabilitation procedures are rarely based upon defined assessment procedures. It might therefore be useful to develop simple and reliable screening tools to identify patients for early discharge, intensified rehabilitation and limited treatment. PATIENTS AND METHODS: 234 patients were initially contacted. From these 217 gave informed consent. The reported study included the 134 home dwelling elderly. All patients could be contacted or died after six month. Thus,data from more than 90% could be used for the analysis. The six month mortality was 10%. A population based cohort of elderly patients referred to five local hospitals was tested. Mortality, institutionalisation and mobility were defined as major outcome criteria. Only information that was available during the first week of treatment was used in the model. Predictors expressed as odd ratios (OR) were calculated using logistic regression with variable selection. RESULTS: The most important predictors for institutionalisation were age, inability to eat without assistance, postoperative night time confusion, stroke history, cognitive deficit and fear of falling. Outdoor mobility was strongly associated to the preoperative ADL performance measured as the Barthel-Index, history of malignancy and fear of falling. Six month mortality was associated with male sex, the Barthel-Index and fear of falling. DISCUSSION: It seems feasible to improve postoperative resource allocation by predictor led stratification. This need to be tested in intervention trials under the specific condition of the German health care system.

Activities of Daily Living↗

[Occupational disease 2108. Degenerative changes of the cervical spine as a causality criterion in the assessment of discogenic diseases according to BeKV 2108].

With the second amendment to the Ordinance on Occupational Diseases (BeKV) of 18 December 1992, discogenic diseases of the spine are included in the disease register of occupational diseases for the first time. If occupations that impose stress on the spine have been practised for many years, the possibility exists of recognizing degenerative diseases as an occupational disease. In assessment practice, the radiological data on the spine exposed to stress is compared with that of regions which are remote from the stress (cervical/thoracic spine). This pattern of the distribution of degenerative disease is then used as the basis for determining a causal relationship between the occupation causing the stress and disease of the axial skeleton. The pattern of degeneration of the cervical spine was investigated in two groups, one with ( n =153) and one without ( n =333) occupations that impose stress on the lumbar spine. A cumulative score of degenerative changes was elaborated and presented as a new classification. No differences were found between the groups with regard to either the frequency of occurrence, segmental distribution or severity of disease. In both groups, degenerative changes correlated with age. The prevailing assessment practice is discussed on the basis of these data.

Adult↗

[Quality of life after surgical treatment of osteitis].

Although many studies have measured the functional outcome after surgical treatment of osteomyelitis, there have been few published attempts to evaluate the long-term quality of life. We therefore undertook this study to assess the quality of life in a large patient population after operative treatment for this condition. All patients who underwent operative treatment for osteomyelitis from 1993 until 1997 at our institution were included in the study. The patients were assessed with a questionnaire which contained the SF-36 (German version) and questions about the activity and history of the illness. The result was compared to the data set from a standard population. Of the 502 patients, 345 (69%) returned questionnaires for evaluation. The infection was inactive in 301 (88%). Compared to a standard population, the investigated patients showed a significant reduction in their overall psychological well being and physical functional capacities. Surgical treatment was able to inactivate the infection in 88% of the patients. Because of persistent deficits, the psychological well being and physical functional capacities are reduced compared to a standard population.

Adolescent↗

[Radiation dosage in orthopedics -- a comparison of computer-assisted procedures].

Since the 1990s, computer-assisted methods have been well-established in the field of orthopedics and traumatology. In addition to the proven improvement in the field of surgical precisioncompared with conventional techniques, the decrease in the amount of emitted ionizing radiation inside of the operating room was cited to constitute an additional major advantage of computer-based navigation. The goal of this study was to quantify X-ray dose values exposed during both conventional methods and computer-assisted procedures, the latter being performed using a C-arm device SIREMOBIL Iso-C3D (Siemens Medical Solutions). The clinical measurements were supplemented by laboratory experiments using a pinpoint ionization chamber placed inside a standard lucite phantom. The clinical part of the study investigated the application of new, i.e. computer assisted, techniques in comparison with conventional procedures on in total 42 patients experiencing surgery either on their lower extremities (n = 14) or on the spine (n = 28). The techniques applied were: (1) conventional surgical procedure, (2) CT-based navigation, (3) C-arm navigation, and (4) Iso-C3D-navigation. The main focus of the clinical evaluation was the determination of radiation dose values by means of thermoluminescence dose meters, accompanied by the registration of the operation times of the X-ray tube during a surgical intervention. The conclusions from the clinical studies are in agreement with the results from the laboratory measurements. Computer-assisted techniques led to a significant reduction in X-ray dose exposure and drastically shortened irradiation times. The most pronounced decrease in the emission of ionizing radiation was achieved in case of the Iso-C3D-navigation, which has only recently been introduced into clinical practice, i.e. during runtime of this study.

Humans↗

[Fatal outcome after multiple trauma. The thoracic injury as the decisive factor].

In patients suffering from multiple injury, chest trauma is often the main cause of fatality. A case report is given and the literature reviewed.A 49 years old motorcyclist hit a car frontally in a road accident. After primary stabilization and first clinical care, he was transferred to our trauma centre because of severe chest injury, suspected pericardial effusion and lesion of the thoracic aorta. Initial diagnostics (plain radiographs, CT scan of thorax, abdominal ultrasound, echocardiography) showed left-sided serial rib fractures, a fracture of the left scapula, a hematopneumothorax left-sided, bilateral lung contusion, a small pneumothorax of the right side, a minimal pericardial effusion and a small splenic hematoma. The patient was treated in the intensive care unit, and the situation was initially stable. After 12 h, respiration deteriorated and a bronchoscopy showed filling of the airways with mucous fluid. The CT scan showed a worsening of the pulmonary damage and increasing pericardial fluid compression. A pericardiotomy was carried out, but the situation remained unstable. The patient was treated with invasive ventilation (PEEP>10, FiO2>0,5). Sudden severe bleeding out of left lower lobe was managed by thoracotomy and lobectomy. The patient remained unstable and died 95 h after the accident. This case shows that the severity of chest trauma does not necessarily correlate with the initial clinical and radiological findings. Even with all diagnostic and therapeutic procedures, a fatal outcome could not be prevented. This demonstrates the role of chest injury as a major and unforeseeable cause of death in multiple trauma patients.

Accidents, Traffic↗

[Navigation of tumors and metastases in the area of the thoraco-lumbar spine].

In this clinical feasibility study, CT-based verification of the efficacy of navigated decompression and pedicle screw placement in patients who had tumor-related posterior surgery was demonstrated. Eighty-six percent of the pedicle screws were positioned centrally in the bone without perforation; in all patients accurate decompression was seen. The accuracy of transpedicle screw implantation postoperatively was investigated with CT. In contrast to other published studies, no postoperative neurologic deterioration was seen in the patients as a result of using computer-aided surgical procedures. At the same time we were able to achieve complete decompression of the neural structures for radiologic and neurologic findings. Because of inaccurate registration, it was not possible to use computer-aided implantation surgery for 15% of the pedicles and, therefore, a conventional fluoroscopic approach was used. Our initial results indicate that computer-aided frameless navigation of tumor surgery of the spine is a safe technique which improves surgical performance during posterior decompression and transpedicle stabilization. In addition, CAS surgery improved the intraoperative information about the tumor and the current surgical intervention during decompression. Nevertheless the technique should be used only by experienced surgeons who can, if required, continue the operation using conventional techniques. Furthermore, the surgeon should have a complete theoretical understanding of the navigation system to minimize possible misinterpretation of computer guidance information.

Bone Screws↗

[Precision of navigation-assisted surgery of the thoracic and lumbar spine].

The goal of these studies was to evaluate the accuracy of in vivo and in vitro application of CT- and C-arm-based navigation at the thoracic and lumbar spine. With CT based navigation, 82 pedicle screws were consecutively inserted, 53 into the thoracic and 29 into the lumbar spine. Seven (13%) perforations were detected at the thoracic spine and two (7%) at the lumbar spine. Additionally, minor perforations below the thread depth were seen in six (11%) thoracic and in two (7%) lumbar instrumentation. With C-arm-based navigation, 74 screws were consecutively placed into 38 thoracic and 36 lumbar pedicles. Perforations were noted in ten (26%) thoracic and four (11%) lumbar implants. Minor perforations were observed in another nine (24%) thoracic and ten (28%) lumbar pedicles. The observer-independent and standardized in vitro study based on a transpedicular 3.2-mm drill hole aiming a 4-mm steel ball in a plastic bone model showed pedicle perforations of the drill canal only in thoracic vertebrae, 1 of 15 in CT-based and 3 of 15 in C-arm navigation. The quantitative calculation of the smallest distance between the central line through the drill canal and the center of the steel ball resulted in 1.4 mm (0.5-4.8 mm) for the CT-based navigation at the thoracic spine and in 1.8 mm (0.5-3 mm) at the lumbar spine. For the C-arm based navigation the distance was 2.6 mm (0.9-4.8 mm) for the thoracic spine and 2 mm (1.2-3 mm) for the lumbar spine. In our opinion, the clinical results of the comparative accuracy of CT- and C-arm-based navigation in the present study showed moderate advantages of the CT-based technique in the thoracic spine, whereas CT- and C-arm based navigation had comparable perforation rates at the lumbar pedicle. The results of the experimental study correlated with the clinical data.

Bone Plates↗

Guidelines for the intramuscular positioning of EMG electrodes in the semispinalis capitis and cervicis muscles.

The objective of the study was to establish guidelines for the application of fine-wire or needle electrodes in the semispinalis cervicis and semispinalis capitis muscles. First of all, measured data for the puncture angle and puncture depth of each muscle were determined in CT scans. Using a regression approach, a model relation of these data with the neck circumference was established. This made it possible to accurately determine the puncture angle and puncture depth on the basis of the known neck circumference. In a further step, the neck muscles of seven human cadavers were punctured with wires in order to check the workability of these guidelines. At the same time, the wires' positions in relation to important structures (nerves, vessels) were studied. Both muscles can be punctured with a high degree of reliability. However, when puncturing the semispinalis cervicis muscle, one has to pass through a layer that contains vessels, nevertheless the risk of injury is regarded as very small. The technique enables intramuscular EMG measurements of the two muscles in manifold clinical problems.

Electrodes↗

[Osteotomies in malalignments of the lower extremities].

The surgical correction of malalignments of the lower extremities is a very demanding procedure. It requires extensive knowledge of: (1) fundamental lower extremity biomechanics, (2) various diagnostic modalities, and (3) methodology for multidimensional preoperative planning. Despite advanced techniques in diagnostics and surgery, the history of the patient and a physical examination are still the first steps in the diagnostic chain. The knowledge of the method-dependent normal values, their physiological range and intra-individual differences are a prerequisite. In posttraumatic deformities, the healthy leg is a good reference for the patient's geometric orientation. As a rule, values differing by three times the standard deviation or more are good indications for an operation. These are 15 and 12 mm for the upper and lower leg, 18 and 15 mm for the whole leg and only 3 degrees mm for the mechanical leg axis measured using computer tomography and long standing x-rays, respectively. The indication for surgical correction is not only based on geometric data. The patient's functional needs, symptoms, complaints and compensation possibilities must also be taken into account. The lower extremities have to be assessed in a psychosocial context. Among the huge number of possible surgical techniques, the procedure best suited for the patient has to be selected. This requires extensive knowledge and advanced technical skills from the treating orthopaedic surgeon. In supracondylar or high tibial osteotomies for the treatment of medial arthritis of the knee joint, the patient should be informed of the long term prognosis and endoprosthetic alternatives. Today, percutaneous epiphysiodesis is a very reliable and minimally invasive surgical technique for correcting the length and axis of the lower extremity in children between 10 and 14 years. With well planned epiphysiodesis procedures, it is often possible to avoid complex osteotomies in younger patients.

Adolescent↗

[Time optimized modern shock room management using digital techniques].

Emergency room management means time management. A time and four color based algorithm is described to improve workflow, follow up of diagnostic procedures and initial treatment. As a result introducing the time based interdisciplinary emergency algorithm within 60 minutes all necessary treatment and diagnostic procedures were completed. This algorithm is an effective tool to improve emergency room treatment.

Algorithms↗

[Costs for acute, stationary treatment of polytrauma patients].

Are the costs required for a polytraumatised patient sufficiently paid by the health care companies?The study population consisted of 71 polytrauma patients. The treatment-costs were calculated and compared with the reimbursements. The mean patient age was 38.0 years with a mean injury severity score (ISS) of 23.0 points. The mean duration of hospitalisation was 25.9 days and the mean calculated cost per patient was Euro 21,866.30. The reimbursement was only Euro 16,863.03/patient. This leads to a financial deficit of approximately Euro 5,000/patient (Euro 167/polytrauma patient/hospital day) and nearly Euro 355,000 for all patients during the period of 1 year. The introduction of the DRG system endangers the high standard of polytrauma treatment because of insufficient reimbursement.It is necessary to consider the implementation of an additional polytrauma-reimbursement based on the injury severity and duration of hospitalisation. The concentration of the patients in trauma centres, where the optimum of therapy is guarantied, leads in these hospitals to a continuously increasing deficit. The latter may be deleterious for the concept of "trauma centers" in the future.

Adult↗

[MAC-TL twin screw. A new thoracoscopic implantable stabilization system for treatment of vertebral fractures--implant design, implantation technique and in vitro testing].

Due to the lack of an appropriate instrumentation system for minimally invasive procedures to treat spinal fracture, a new thoracoscopically implantable stabilization system was developed. This report describes the new implant design and implantation technique. In a biomechanical in vitro study, an anterior corpectomy model representing the worst case of burst fracture instability was simulated, and the primary stability parameters of the new system were evaluated in comparison to a dorsal stabilization system. With the interbody graft and fixation, the new system demonstrated higher stabilizing effects in flexion/extension and lateral bending and restored axial stability beyond the intact spine and the dorsal stabilization system. Considering all the advantages of the endoscopic procedure and this biomechanical characterization, the clinical trial is warranted; its usefulness has been demonstrated in more than 150 cases in a multicenter study to date.

Aged↗