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Biomedical subjects

G Lob

Publications and source records attributed to G Lob.

At least 37 records · Page 2Linked to original sources

Fixation of osteotomies of the distal femur with absorbable, self-reinforced, poly-L-lactide plates. An experimental study on rabbits.

Osteotomies of the distal femur were fixed with two self-reinforced poly-L-lactic acid (SR-PLLA) plates and metallic screws placed through the plates on each side of the femur in 23 adult rabbits. They were followed-up after 3, 6, 12 and 24 weeks. After killing, radiological, histological, microradiographic and oxytetracycline fluorescence studies were performed. Except for one histologically confirmed fibrotic non-union at 24 weeks, the osteotomies healed, including one involving a rabbit which had suffered an ipsilateral femoral shaft fracture of unknown cause. No malformations were observed, and the macroscopically detected swelling was a normal postoperative reaction. This study showed that SR-PLLA plates implanted on both sides on the bone are suitable for the fixation of weight-bearing cancellous bone osteotomies in rabbits.

Absorption↗

Intraosseous plating with absorbable self-reinforced poly-L-lactide plates in the fixation of distal femoral osteotomies on rabbits.

Osteotomies of distal femur were fixed by intraosseous self-reinforced poly-L-lactic acid (SR-PLLA) plates in 29 adult rabbits. The follow-up times were from 3 to 24 weeks. After sacrifice, radiological, histological, microradiographic, and oxytetracycline fluorescence studies were performed. Although radiographically no redisplacements were found, in 12 weeks two fixations were broken and a fibrotic nonunion was observed in one case. At 24 weeks full bone consolidation was seen in all except one osteotomy. No foreign-body reactions were observed. The present article is the first report on successful application of absorbable plates for intraosseous fixation of weight-bearing bone osteotomies. The present investigation demonstrated that the SR-PLLA plates were suitable for the fixation of cancellous bone osteotomies in rabbits.

Animals↗

[Current issues regarding fracture treatment in elderly patients].

According to demographic studies in Germany about 95,000 proximal femur fractures (PFF) in patients aged over 65 will occur in the year 2030; that means around 40% more than in 1995 (n = 68,233). These injuries lead to very high socio-economic costs and only PFF therapy with a rapid full-recovery could be a useful solution. At present PFF treatment consists mainly of operative osteosynthesis with a mortality rate of only 4% (own study of 100 patients). In contrast, the long-term efficiency of PFF therapy is poor because statistically nearly every second patient requires partial or full-time help. Clearly, postoperative training is, as yet, insufficient. But only a complete PFF therapy (operation and intensive postoperative physiotherapy, ergotherapy and geriatrics) can improve the long-term results, thereby reducing costs and social problems which would otherwise only worsen in the future.

Activities of Daily Living↗

Thoracoscopic repair of thoracic spine trauma.

Modern concepts of treating thoracic and lumbar spinal trauma are based on posterior transpedicular fixation techniques which confer angular stability and instrument only a few levels of the spine. In addition, to prevent secondary losses in postoperative reduction of kyphotic deformities, transpedicular resection of torn discs, and inter- and intracorporeal bone grafting are included in the repair procedures for the entire damaged motion segment. However, due to the small size of the pedicles, a transpedicular approach to the injured vertebral body is not possible in the upper thoracic spine. Patients whose thoracic spine trauma is not serious enough to require ventral instrumentation through open thoracotomy, but who present with an unstable vertebral fracture, may profit from additional ventral bone grafting to stabilize the fracture. The present study examined the feasibility of thoracoscopic ventral bone grafting in seven patients with unstable fractures of the upper thoracic spine. For primary repair, we stabilized the fracture by using posterior transpedicular screw systems (rods or plates). Simultaneously, spongiosa was harvested from the posterior iliac crest and deepfrozen. Repair was completed a few days later via a ventral thoracoscopic approach. The main location of the ventral osseous defect was identified by intraoperative radiology. After mechanical removal of destroyed connective tissue and disc material, fusion was performed using the previously harvested spongiosa, which was placed into the intervertebral disc space and the anterior osseous defect. Our results show thoracoscopic bone grafting to be technically possible and associated with low morbidity, with a potential of yielding satisfactory long-term results.

Adult↗

Posterior stabilization of C2 metastases by combination of atlantoaxial screw fixation and hook plate.

A new technique for the stabilization of metastatic cervical instability of the axis and/or neighboring vertebrae at lower levels is described. By a combination of the transarticular screw fixation C1/2 (Magerl) with the hook plate technique (Magerl) (or facultatively with a 1/3 tubular or 3.5 mm dynamic compression plate) from a posterior approach, the risks and stresses on the patient of a transoral or a combined extended technique are avoided, creating a proven biomechanically stable situation. The new technique is particularly helpful in those patients with a rapid progression of their malignant disease in whom local tumor growth is not expected to compress the spinal cord, and palliative stabilization of the unstable upper cervical spine can avoid neurological deficits or alleviate pain syndromes at a minimized morbidity due to surgery. The new technique has been successfully applied in a limited clinical series of four patients with metastasis of the cervical spine, resulting in substantial improvement of the general condition and cervical pain syndrome and stability of the assemblage during the observation period (4-9 months).

Adult↗

Analysis of morphology and gait function after intraarticular calcaneal fracture.

Open reduction and internal fixation is suggested by an increasing number of investigators as preferable treatment of displaced intraarticular calcaneal fractures. Assuming that quasianatomical reduction coincides with adequate function, many surgeons rely on morphological parameters (standard radiography, computed tomography) to demonstrate the effectiveness of surgery by achieving an optimum restoration of calcaneal geometry and joint surfaces. In order to correlate morphologic parameters and functional assessment, a prospective study was performed on 45 patients after surgical treatment of intraarticular calcaneal fractures using standard radiographic and computed tomographic scores, clinical evaluation, and gait analysis (dynamic pedography). Mean follow-up time after reconstruction was 23 months (range 18-50). Although clinical evaluation and assessment of gait function corresponded well with each other, radiographic scores showed a poor to moderate correlation with functional evaluation (r = 0.29-0.62); this was probably due to the missing analysis of soft tissue parameters. The comparison of clinical results and gait parameters with the individual radiographical parameters allowed us to identify those factors, with the greatest influence seen on the functional prognosis (i.e., calcaneal width, arthrosis in the neighboring joints). Morphologic analysis after calcaneal reconstruction based on radiographic techniques cannot predict subsequent function or substitute for functional assessment. However, it does allow for practical conclusions for surgical strategy in primary osseous reconstruction or secondary corrections.

Activities of Daily Living↗

[Surgical treatment strategies in femoral metastases].

Because of the increasing survival-time of tumor-patients bone metastasis is becoming an important subject in surgery. In the case of osteolysis of the femur a concept of treatment in consideration of various localisations is presented. In 81 patients with pathological fractures of the femur or osteolysis in this region from January 1987 to June 1992 96 stabilizing operations were performed. Almost one half of the patients suffered from breast carcinoma followed by hypernephroma, Plasmocytoma, bronchial-carcinoma and prostate-carcinoma. The average survival time after stabilization of the femur was 8.3 months. After the operation the condition of the patients improved on an average by 0.64 units of the modificated Karnowsky-Index. Surgical treatment of osteolysis in the femur is indicated either in pathological fractures or if instability is imminent. Moreover patients who suffer from severe pain should also receive palliative surgery. With regard to the site of the lesion various types of endoprostheses and osteosynthesic devices can be used. If the femoral neck or the intertrochanteric region is affected arthroplasty with cemented endoprosthesis may be performed. In subtrochanteric osteolysis long and thin endoprosthesis can be used as well as Gamma-nails. Pathological fractures in the shaft of the femur should be treated with intramedullary static locked nails, which can be strengthened by supplementary lateral plates. If the distal metaphysis of the femur is involved compound osteosynthesis with methylmethacrylate and dynamic condylar screws or angle plates can be used.

Female↗

Injuries in paragliding.

In a retrospective study, 376 paragliding accidents have been analysed. Leg injuries were most common, but a large number of spinal injuries also occurred. The causes were either misjudgement by the pilot or the influence of weather and terrain. Improvements in the instructor's knowledge and the pilot's training could have prevented most of the accidents. Analysis of the mechanisms of the crashes and the pattern of trauma help to produce an efficient approach to diagnosis and treatment.

Accidents, Aviation↗

[Experiences with the isoelastic prosthesis in treatment of humerus metastases].

39 patients with pathological fractures of the humerus were treated by isoelastic polyacetal endoprosthesis. Ten patients received a humeral-head-prosthesis and 32 a prosthesis of the humeral-shaft. The average survival time was nine months. Three times within the first group of twelve patients fracture of the cone of the prosthesis occurred. Therefore an additional stabilization of the contact zone between bone and prosthesis by plate-osteosynthesis was performed in the following 20 operations, preventing breakage of the material. In contrast to the conventional posterior approach to the humeral-shaft we chose a ventrolateral approach between the biceps and triceps muscle. This technique is less traumatic and leads to a shorter operation time. In patients with pathological humeral fractures a conception of treatment is demonstrated which provides an immediate stability by using endoprostheses to preserve the quality of life of oncological patients.

Bone Neoplasms↗

Anterior transpedicular instrumentation of the lumbar spine: an anatomical study.

Lumbar burst fractures or massive tumorous destruction of the lumbar spine generally require a combined anterior-posterior surgical approach for adequate decompression and stabilization. Anatomical studies in 10 adult cadavers with 100 pedicle screw placements from a single strictly anterior approach showed that this new method represents a safe and promising way for stable lumbar spine instrumentation, avoiding the risks of a bilateral approach. The technique provides a stability comparable with bilateral instrumentation. Exact knowledge of the geometry of the corresponding vertebral bodies and the spinal canal by computed tomography scanning is a prerequisite for this surgical technique. First clinical applications using this technique reconfirm the experiences of the anatomical study.

Adult↗

[Extension-distraction injury of the lumbar spine in Bechterew's disease].

Back-pain following trauma of the vertebral column in patients suffering from Bechterew's disease should be examined carefully. Instable spine fractures in those patients are recommended to be treated surgically to avoid the specific risks of long-time immobilisation. Further on surgical therapy eventually allows an intraoperative correction of the kyphosis angle. Due to the particular pathological alterations of the spine in Bechterew's disease a long-distance intervertebral fusion will usually be necessary. Therefore, internal stabilisation is proposed as therapy of choice.

Adult↗

Compartment syndrome of the foot after intraarticular calcaneal fracture.

Seventeen patients with a total of 21 intraarticular calcaneal fractures were examined at up to 30 days after trauma for the development of tissue pressure in the central plantar muscle compartment. Twelve patients had a significant increase in tissue pressure with values greater than 30 mmHg because of primary fracture hematoma or interstitial fluid accumulation. This increase in pressure persisted for three to five days after trauma, so that ischemic damage to the short plantar foot muscles had to be suspected. Plantar muscle scarring and claw-toe formation were observed in seven patients with a total of 11 fractures during a mean observation period of 18 months. The plantar aponeurosis, which forms the constricting fascial envelope of the plantar muscles, is the anatomic structure responsible for the compartment syndrome that may develop after calcaneal fracture. Therefore, to avoid functional deficit, plantar compartmental pressures should be regularly measured after calcaneal fracture. Significantly increased plantar tissue pressure greater than 30 mmHg should be relieved by longitudinal incision of the plantar aponeurosis, preferably by a plantar incision as soon as the diagnosis is made.

Adolescent↗

[Hanggliding--the Icarus syndrome].

Parasailing is a new sport resulting in an increasing number of severe injuries. The analysis of 152 accidents reveals typical trauma mechanisms for the different flight positions. 87 patients (57%) had their crash during the landing approach. 68 pilots (45%) were affected during their primary training course. Spine lesions were found in 30 patients. Lower limb injuries occurred in 44 cases. Detailed trauma evaluation can give a clue for systematic prophylaxis.

Accidents, Aviation↗

The influence of bacterial contaminations on the biodegradation of PLA implants.

Metal implants employed in orthopaedic surgery have certain disadvantages. Intensive research work is therefore being done in the field of biodegradable implants, the behavior of which in the case of possible contamination or infection at the operation site has not yet been studied. In-vitro experiments on PLA-test bodies were performed to clarify the influence of bacteria on the polymer degradation. The investigated parameters were germ growth, course of the pH-value of the culture media, bending stiffness of the PLA-test bodies and the decrease in their molecular weight. The experiments performed did not demonstrate an accelerated degradation of PLA specimen in vitro incubated in different bacterial contaminated media. Therefore bacterial contamination may possibly not lead to a premature collapse of the PLA used in connection with fracture treatment by biodegradable osteosynthesis implants.

Bacterial Infections↗

[Tendon rupture in chronic kidney insufficiency--"uremic tendonopathy"? A literature-supported documentation of 3 cases].

This is a report on three cases with spontaneous ruptures of major tendons of the lower extremities. In two cases ruptures occurred in the quadriceps tendon, one of them bilaterally, and in one case in the Achilles' tendon. All patients suffered from chronic renal failure and were treated by long-term hemodialysis. Coincidentally secondary hyperparathyroidism was noticed twice. The pathophysiological relation between chronic renal failure and spontaneous tendon rupture is still unknown. An "uremic tendopathy" is discussed.

Achilles Tendon↗

[Causes and pathophysiology of infection of the knee joint].

The origin of an infection of the knee joint can be of an endogenous/hematogenous nature or, in posttraumatic cases, of an exogenous nature. Hematogenous infections are found mostly in children, but also in patients with reduced immune functions, e.g. after organ transplantations. Posttraumatic joint infections are caused by open injuries, intraarticular injections, operations, or they can be transmitted from the surroundings. They are relatively rare after accident surgery and orthopedic surgery. Two statements are of special importance for pathophysiology: 1. An intraarticular infection will lead to lesions of the hyaline cartilage within a period of 24 to 48 hours. 2. The substrate exchange is reduced by the reflex immobilization which will result in a additional damage to the cartilage.

Arthritis, Infectious↗