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Biomedical subjects

G Muhr

Publications and source records attributed to G Muhr.

At least 109 records · Page 6Linked to original sources
PubMed2000

[Fatal soft tissue infections after arthroscopy of the knee joint. A diagnostic or therapeutic problem?].

After detection of a bacterial infection of the joint, an absolute indication for intervention is given. Systemic antibiotic drug therapy is indicated and drainage of the joint has to be performed immediately. The following therapeutic algorithm regimen is a proven remedy in treating pyoarthrosis of the knee joint: During the initial period, the infection can be controlled by arthroscopic irrigation and systemic antibiotic therapy. Depending on the progredient findings or if the symptoms persist, curing the joint by open synovectomy is the next step of treatment. If open joint revision including synovectomy is not performed or is performed too late, there will be a threat of irreversible damage of the afflicted joint up to septic spread endangering the patient's life. We report on two patients suffering from generalized sepsis resulting in death after delayed therapy for knee joint infection. Regarding the presented cases, it can be concluded that indication to early surgical joint debridement including open synovectomy of the knee is still rarely seen after development of pyoarthritis.

Algorithms↗
PubMed2000

[Fracture management in the aged].

Fracture care in a geriatric population should lead to a mobilisation with full weight bearing as soon as possible after the accident. Osteoporosis and associated preexisting disease influences the kind of fracture care as well as the social situation. A retrospective analysis of 888 consecutive patients from 1994 to 1998 showed that the fracture risk for a second independent bony lesion was 5.2% in this population with a mean age of 83.4 years (75 y-97.2 y). 946 fractures were treated operatively with a overall reoperation rate of 10%. 3.1% were soft tissue revisions due to infection, 2.0% were because of implant failure in connection with a deep infection and 5.2% of the reoperation were indicated because of implant failure alone. Distribution of complications showed the advantage of closed, indirect reduction and intramedullary devices and primary hemiarthroplasty in femoral and humeral head fractures.

Aged↗
PubMed2000

[Femoral neck fracture. Osteosynthesis or which endoprosthesis is indicated?].

Femoral neck fractures are frequent fractures of the elderly. They can be treated by the use of dynamic hip screws, lag screws, bipolar hemi-protheses or total hip replacement. The results are markedly influenced by the timing of the operation and the choice of the implant. Using the Garden classification of femoral neck fracture we demonstrate a different therapeutic approach according to Garden stadium I-IV.

Aged↗
PubMed2000

Effects of single-dose versus fractionated irradiation on the suppression of heterotopic bone formation--an animal model-based follow-up study in rats.

The histological and enzymatic effects of single-dose irradiation of 7 Gray (Gy) versus fractionated irradiation of 5 x 2 Gy on the suppression of heterotopic ossification were examined over a period of 60 days in adult male Wistar rats (n = 57). The standardized osteogenesis model system in rats 19, 10, 11, 16, 19] was used for this purpose. The course of developing ossifications was documented quantitatively and qualitatively by means of quantitative computed tomography/osteodensitometry and digital luminescence radiography. Assessment of the activities of the enzymes alkaline and acid phosphatase throughout the experiment as well as characterization of the isoenzyme of alkaline phosphatase (AP) in connection with histological observations displayed a metaplasia of the ingrowing connective tissue into bone-typical cells during osteoinduction. Thus, the increase of AP is the first sign of a functional transformation of mesenchymal stem cells into chondroid bone cells. The increase in the acid phosphatase level with a maximum of activity between the 15th and 30th day (according to the respective treatment group) is highly suggestive of a remodeling process paralleling incipient chondroclast and osteoclast activity. In the animal groups undergoing irradiation, the above-mentioned increase of enzymes occurred after a delay. Furthermore, the maximum values observed were lower than those in the group not undergoing irradiation. Both findings were more manifest in the animal group which underwent 5 x 2 Gy of radiation than in the group which underwent single-dose irradiation of 7 Gy. Radiation suppresses matrix-induced osteogenesis. The histological and enzymatic course of this process was unchanged in the animals which did not undergo irradiation. However, it was quantitatively reduced and accompanied by a retardation of osteogenesis. Both effects were again reduced with fractionated irradiation of 5 x 2 Gy, which is theoretically dose-equivalent to a 1 x 7 Gy application. Histological examinations revealed damage to the migratory, proliferating mesenchymal stem cell population by irradiation doses which had relatively small effects on preosteoblasts, osteoblasts, chondroblasts and other specialized cell forms. Therefore, it may be concluded that the smaller degree of heterotopic ossification in the irradiated groups was due to damage of and a decrease in the number of mesenchymal stem cells at the implant site. Our results stress the necessity of instituting postoperative irradiation therapy as early as possible to prevent heterotopic ossification. In view of experimentally proven better effects, fractionated irradiation has to be preferred to a dose-equivalent single-dose radiation, especially considering the fewer side-effects noted with fractionated irradiation.

Acid Phosphatase↗
PubMed2000

Fixation of proximal tibia fractures by a retrograde nail: a biomechanical investigation.

Surgical treatment of proximal tibial fractures requires open reduction and internal fixation. The operative exposure causes additional soft-tissue injury and reduces the blood supply to the bone. A cephalograde tibial nail should offer comparable mechanical stability without these disadvantages. We compared the stability of both osteosyntheses in a fracture model with 12 fresh-frozen cadaver bones. While both implants exhibited comparable stiffness under sagittal loading, the plate had a higher rotational and varus stiffness. Despite this higher stiffness, rotational displacements at the fracture gap were nearly twice as large for this implant during loading. We conclude that the retrograde nail provides similar mechanical stability to plate fixation for proximal tibial fractures, while the closed reduction and soft-tissue preservation of this new technique are definite advantages.

Biomechanical Phenomena↗
PubMed2000

Traumatic spondylolisthesis of the axis: treatment rationale based on the stability of the different fracture types.

Thirty-nine consecutive patients, 22 male and 17 female with an average age of 37.6 years, with traumatic spondylolisthesis of the axis were reviewed. The cause of injury in 75% of the patients was a road traffic accident. The fractures were classified according to Effendi et al., the type II fractures were further divided into three subgroups: flexion, extension and listhesis injuries. There were 10 type I (25.7%) and 29 type II fractures (74.4%); of these, 12 (30.8%) were classified as flexion-type, 2 (5.1%) as extension-type and 15 (38.5%) as listhesis-type. We did not identify any case of type III injury. Overall, 43.5% of the patients had sustained a significant head or chest trauma, with the highest incidence for type II listhesis injuries. Significant neurological deficits occurred in four patients (10.3%); in all four,the fracture was classified as a type II listhesis. All ten type I injuries were successfully treated with a cervical orthosis. Ten of the 12 type II flexion injuries demonstrated significant angulation. Two were treated with internal stabilisation, in seven with a halo device and one with a minerva plaster of Paris (PoP). Healing was uneventful in all ten patients. For the remaining two stable type II flexion injuries, application of a hard collar was adequate, as was the case for the two stable type II extension injuries. Six of the 15 type II spondylolisthesis injuries underwent primary internal stabilisation, and healing was uneventful in all cases. In four (44.4%) of the nine injuries that were primarily treated with a halo device/minerva PoP, secondary operative stabilisation had to be performed. The classification of Effendi et al. provides a complete description of the different fractures. However, further distinction of the type II injuries regarding their stability is mandatory. Type II spondylolisthesis injuries are unstable, with a high number of associated injuries, a great potential for neurological compromise and significant complications associated with non-operative treatment. The majority of type II extension and type II flexion injuries can be successfully treated with nonrigid external immobilisation.

Adult↗
PubMed2000

Ultrasound and bronchoscopic controlled percutaneous tracheostomy on trauma ICU.

Tracheostomy is a common surgical procedure performed in long-term ventilated patients in intensive care. Since the role of percutaneous dilatational tracheostomy (PDT) on Intensive Care Unit (ICU) has become steadily more important in the last few years, a prospective study was started to evaluate the economic efficiency and to show the minimization of the complication rate of this procedure. In 72 patients we performed PDT as a bedside procedure. Initially the thyroid gland and the subcutaneous vessels were studied by ultrasound in every patient. The puncture of the trachea, the dilatational procedure and the insertion of the tracheal cannula were executed under bronchoscopic monitoring. Finally, a bronchoscopic control view followed via the new cannula to detect intratracheal complications. Mechanical ventilation was maintained during the procedure and controlled by continuous pulse oximetry. According to prior ultrasound findings the place to puncture the trachea was changed in 24% of the patients, in one case tracheostomy was performed as an open conventional procedure. The following complications could be observed: one case involving perforation of a cartilaginous ring, one case with venous bleeding of a small subcutaneous vein and two cases with punctures of the bronchoscope. There were no cases of miscannulation, penetration of the posterior tracheal wall or major bleeding requiring intervention or conversion. The followup study revealed that there was no sign of further complications in any patient. In addition, cost analysis demonstrated that there was a significant economical advantage of PDT in comparison with open standard tracheostomy. Standardized ultrasonographically and bronchoscopically controlled PDT turns out to be a safe, simple and cost effective bedside procedure on ICU. Because of ultrasound examination performed before the procedure, and bronchoscopic surveillance during the procedure, safety of this procedure can be enhanced, thus minimizing the rate of complications.

Adult↗
PubMed2000

[Pattern of injuries and prophylaxis in paragliding].

This study will present trends and recommendations to increase active and passive safety in paragliding on the basis of current state-of-the-art equipment and typical patterns of injury. This German-Swiss teamwork presents data of 55 male and 9 female patients treated after paragliding accidents between 1994 to 1998 respectively 1996 to 1998. 43.7% of the pilots presented with multiple injuries, 62.5% suffered spinal fractures and 18.8% pelvic fractures. 28.4% of the injured pilots were admitted with injuries of the lower extremities mainly affecting the tarsus or the ankle joint. Only three patients with single injuries could be treated in an ambulatory setting. 54.0% of the injuries left the patients with lasting functional residues and complaints. Main causes of accidents were either pilot error in handling the paraglider or general lack of awareness about potential risk factors. 46.0% of injuries occurred during landing, 42.9% of injuries during the flight and another 11.1% of injuries during starting procedures. With noticeable enhanced performance sails of the beginners and intermediate level are increasingly popular. Protective helmets and sturdy footwear reaching above the ankle joint are indispensable pieces of equipment. The use of protective gloves is highly recommended. Back protection devices of the new generation provide the best passive prophylaxis for the pilot against pelvic and spinal cord injuries. This area hold the most promise for increasing safety and reducing risk of injury in future, apart from using beginners and intermediate wings. After acquisition of the pilot license performance and security training provide the best preparing to master unforeseeable situations.

Accident Prevention↗
PubMed1999

[Supination trauma. A classic case].

Sprains in the lateral ligaments of the ankle produce the most common ligamentous injuries of the human body. The mechanism of injury is complex, while supination represents the main component of foot movement. Classifying lateral ankle ligament injuries, many authors use a system of three degrees, which includes mild, moderate and severe sprains. Despite this scientific categories, in our opinion is the differentiation between elongation and complete ruptures of practical relevance. Under a biomechanical point of view, ligamentous trauma of the lateral ligaments lead to acute antero-lateral rotational instability (ALRI). Following the retrospective clinical study of Zwipp with 1,235 patients, in 70% of complete disruptions, the anterior talo-naviculare and fibulocalcanear ligaments are involved together. Syndesmotic injuries have been reported at a rate up to 10% of ankle sprains with deltoid ligaments at 2.5%. Rarely, the classic ankle sprain leads to injuries which affect the foot on a so called "supination fracture line". A rate of 7.4% is reported for these accompanying injuries. Therefore, clinical examination of ankle sprains should not only address on the distal tip of the fibula. Critical bony and ligamentous structures like the fifth metatarsal base, the calcaneo-cuboideal ligament, the ligaments of the anterior calcaneal process, the talus and syndesmotic ligaments have to be screened for pain and swelling. In our opinion, careful clinical examination and plain radiographs in two plains are sufficient for diagnosing ankle sprains and functional therapy.

Acute Disease↗
PubMed1999

[In Process Citation]

Mechanical ventilation is a well-established strategy in intensive care medicine. ICU trauma patients require analgesia, and sedation mostly consists of benzodiazepines and opioids with increasing doses over time. The weaning period is complicated by the withdrawal syndrome, showing tachycardia, hypertonia, tachypnea and restlessness. Although treatment with clonidine can influence these symptoms, tachypnea still remains the main problem in weaning patients from mechanical ventilation. Adding sufentanil, an opioid with greater effects on analgesia than on respiratory depression compared with fentanyl, tachypnea can be reduced to normal frequency. In this way weaning management can be managed more easily for the benefit of both, the patient and physician. In comparison with a group of 50 patients treated with clonidine alone, 72 patients treated with clonidine/sufentanil showed a shorter period from the start of spontaneous ventilation until extubation (4.8 vs 7.6 days) and until discharge from the ICU (7.7 vs 12.4 days). The number of reintubations caused by respiratory exhaustion decreased from 16.0 to 2.8%.

Journal Article↗
PubMed1999

[Prophylactic surgery of the musculoskeletal system].

Prophylactic surgery on the musculoskeletal system has a wide range of indications, for example posttraumatic or non-traumatic malalignment of the lower extremities, joint instabilities or bony lesions with the risk of fracture and secondary malignant change. The goals of treatment include pain relief, improved function and redistribution of the physiological mechanical forces. Clinical experience over the past three decades has defined the current role of realignment of the lower limbs. Recent technological advances have further improved the surgical ability to assess and select patients who are candidates for realignment osteotomy or joint stabilization.

Humans↗
PubMed1999

[Biomaterials in the skeletal system].

The increasing number of biomaterials for the skeletal system requires mote and move their distinct clinical application. To guarantee useful therapeutic results the characteristics of the biomaterials have to be matched with the characteristics of the implantation site. Recently developed biodegradable polymers with a slow degradation process and longer stability are being increasingly clinically applied with a low complication rate. The development of new remodelable bone cements for bone-defect filling revives the idea of cement-metallic implant constructs. Finally, recombinant human bone growth factors are currently under controlled clinical examination with first promising results. Long-term results allowing common clinical use of these factors are still to be expected.

Biocompatible Materials↗
PubMed1999

[Results of posttraumatic elbow arthrolyses: a prospective study].

INTRODUCTION: Posttraumatic stiffened joints are mostly well restored by means of operation, however, the range of motion remains restricted by secondary soft tissue shrinking and scarring. Conservative treatment yields only limited success rates. Open arthrolysis is a useful tool in regaining function; in postoperative treatment, immediate passive mobilization and prevention of heterotopic ossification are most important. METHODS: Sixty-nine patients were arthrolyzed on average 25.3 months post trauma, with an average of 1.5 previous operations (range 0-8) and a follow-up period of 14.7 months. RESULTS: By means of the open arthrolysis, an increase in range of motion for flexion and extension of 62.3 degrees (preoperative 38.4 degrees, postoperative 87.9 degrees, at follow-up 100.7 degrees ) and 29.3 degrees for pro- and supination was achieved on average. The highly important range of motion between 0-30 degrees and 110 degrees was accomplished in 78.2 % of the patients. We analyzed the postoperative management including irradiation, pharmacological ossification prophylaxis with indomethacin and immediate passive motion. Whenever the time to arthrolysis exceeded 9 months, clearly worse results were obtained, thus we measured a difference in the correlated increase of motion from 54.3 % - 34.6 %. Comparisons of our results with German (after Blauth and Hipp) and French (after Cauchoix and Deburge) standard follow-up forms are made, and the rehabilitation program is underlined and explained. Another task of this study was to discuss the complication rate.

Adolescent↗
PubMed1999

[Transport-fixator for reconstructive surgery of the extensor apparatus of the knee joint].

Operative repair in ruptures of the extensor mechanism of the knee joint mostly requires additional external or internal fixation by plaster, transfer of tendons or encircling wires. Reconstruction of initially undiagnosed ruptures has to solve the problems of fixed proximal or distal migration of the patella and tendenous shortening. This can be performed with a tibiopatellar external fixator which allows gradually reduction of the patella in an anatomical position before operative reconstruction by suturing or reinsertion. During this period as well as a post-operative protection this fixator enables patients to maintain motion of the knee joint and full weightbearing. This technique can avoid poor functional results caused by long periods of immobilisation and is helpful in patients with marked displacement of the patella and inability to manually reduce the patella distally when delayed repair is necessitated.

Adult↗
PubMed1999

[Pediatric forearm fractures: indications, technique, and limits of conservative management].

Although several "minimal invasive" techniques for the operative management of pediatric forearm fractures have been developed recently, conservative treatment still remains the option with the lowest risk for small patients. We present the results of our clinical and radiological follow-up after an average of 52.4 months (4-112) in 102 pediatric patients. All fractures were treated conservatively. There were 68 fractures (66.7 %) of the distal third of the forearm, 30 fractures (29.4 %) of the midshaft area, and four fractures (3.9 %) in the proximal third of the shaft. Greenstick fractures were seen in 58 cases (56.8 %), complete fractures with displacement of both corticalices in 26 patients (25.5 %), and folding fractures in 18 cases (17.7 %). With the exception of one fracture with the necessity of remanipulation after redisplacement in the cast, all fractures healed uneventfully without any further intervention. Functional results were excellent with a free range of motion of the wrist and elbow and without any signs of muscular atrophy in 96 children (94.1 %) at the time of follow-up. Six patients, however, showed a significant loss of forearm rotation of an average of 25 degrees (15 degrees -50 degrees ). In four of these six patients, the fracture had been situated in the proximal and midshaft area. Thus, two out of four fractures of the proximal forearm (50.0 %) showed a poor functional outcome. On the basis of our data we recommend conservative management for (closed) pediatric fractures of the distal and midshaft area. Operative treatment is indicated in forearm fractures close to the elbow.

Adolescent↗