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Biomedical subjects

P Patka

Publications and source records attributed to P Patka.

At least 55 records · Page 3Linked to original sources
PubMed1996

The burst phenomenon, an animal model simulating the long-term tissue response on PLLA interlocking nails.

In this in vivo study, low-molecular-weight as-polymerized PLLA powder was placed in the medullary cavity of a porcine femur in order to study the tissue reaction on predegradated PLLA. An attempt was made to simulate the long-term degradation of a large PLLA implant. This phase can be characterized by the release of PLLA particles and acid compounds from a heterogeneously degrading PLLA implant into the surrounding tissues. The clinical consequences and tissue response were studied. The clinical recovery of the experimental animals was favorable. No signs of clinical inflammation could be detected during the eight-week follow-up period. Histological analysis of the bone/PLLA interface showed signs of a mild inflammatory tissue response.

Animals↗
PubMed1996

Effect of (poly)-L-lactic acid on the proliferation and differentiation of primary bone cells in vitro.

A previous study has shown bone formation around poly-L-lactic acid (PLLA) wire in vivo. However, it is still unknown how bone cells are stimulated to form bone around PLLA wire. The effect of PLLA on primary bone cells in vitro is the subject of this study. Osteoprogenitor and osteoblastic cells derived from neonatal mouse calvaria were cultured after addition of PLLA wire or L-lactide to the culture medium. Alkaline phosphatase (AP) activity, as a parameter of bone cell differentiation, and DNA content, to assess cell growth were measured. In osteoblast-enriched cell cultures PLLA wire did not affect DNA content, but AP activity was increased by 28%. In osteoprogenitor-enriched cell cultures PLLA wire decreased DNA content by 10%, but AP activity of the cells was not affected. L-Lactide enhanced the DNA content of osteoblastic cell cultures at 0.1 mM by 19%, but not at higher concentrations, and did not affect cell differentiation. In osteoprogenitor cell cultures, L-lactide had no effect at all. These results indicate that the proliferation and differentiation of bone cells in vitro can be modulated by PLLA, dependent on their stage of differentiation. L-Lactide at concentrations up to 10 mM did not adversely affect cell growth or differentiation, while PLLA wire upregulated the expression of the osteoblastic phenotype. These data support the observation of newly formed bone around poly-lactic acid wire in vivo in other the studies.

Alkaline Phosphatase↗
PubMed1995

Tissue reaction on PLLA versus stainless steel interlocking nails for fracture fixation: an animal study.

In order to develop a biodegradable interlocking nail for fracture fixation, polylactic acid (PLLA) rods were implanted in the femoral bone of young pigs. A midshaft osteotomy was performed in order to mimic a fracture. The tissue response to PLLA rods versus stainless steel rods was studied after 1 and 3 months of implantation. Fracture-healing characteristics and chemical and mechanical properties of the PLLA rods were studied after explantation. Mechanical properties deteriorated during implantation and chemical properties changed significantly in 1 and 3 months of implantation. PLLA and stainless steel induced a similar tissue reaction during the studied implantation time of 3 months.

Animals↗
PubMed1995

Surgical treatment of liver injury with an absorbable mesh: an experimental study.

Uncontrollable bleeding remains a life-threatening problem in severe liver injury. The application of an absorbable mesh has been reported in a small number of patients. To evaluate an absorbable mesh wrap in standardized conditions, we performed an experimental study in 14 female pigs. A standard liver laceration imitating a blunt injury grade IV (Liver Injury Scale of the American Association for the Surgery of Trauma) was made in all animals. Heparin was administered to mimic coagulopathy. After randomization, seven animals received a polyglycolic acid (Vicryl) mesh wrap to control bleeding. Seven animals served as controls. Six of seven animals with a mesh wrap survived. Six of seven animals in the control group died (p = 0.02, Fisher's exact test). Intrahepatic pressures in the treated group varied from 3 to 55 mm Hg. Liver function tests in surviving animals were temporarily elevated. Necropsy at 2 weeks demonstrated adhesions to the wrapped lobe, but no hematoma, free bile, or abscess. Histologic examination showed a foreign-body reaction to the mesh and necrotic parts in the liver. It is concluded that an absorbable mesh wrap can effectively control bleeding from severe liver injury and improve survival in an animal model, although it may cause some damage to liver tissue.

Animals↗
PubMed1995

Closed fracture healing: a rat model.

A rat model for the study of closed fracture healing is described. Standard closed tibial fractures were produced with specially designed pliers in 24 rats. All fractures were located in the middle third of the tibia and healed without complications as delayed union, infection or soft tissue problems. The average angle of the fracture line with the axis of the tibia on lateral view was 80 +/- 2 degrees (SEM). The model is considered to be suited for the study of closed fracture healing processes. Closed intramedullary fracture fixation, can also be evaluated in this model.

Animals↗
PubMed1994

[Reliability of registration of multi-trauma patients].

OBJECTIVE: Evaluation of the reliability of diagnostic codification by the Medical Codification Department (MCD) as a method of national hospital identification of multiple injury patients and description of epidemiology and mortality among the multiple injury group studied. DESIGN: Prospective/retrospective and descriptive. SETTING: Free University Hospital, Amsterdam. METHOD: The injuries of 207 severely injured patients presented at the Accident and Emergency department during the year 1992, were coded as an Injury Severity Score (ISS). Those having an ISS > or = 18 were reviewed on cause and outcome of the injury. The diagnose for codification (International Classification of Diseases-9 Clinical Modification) of the MCD, from which an Abbreviated Injury Score (AIS) and the ISS can be calculated, was evaluated. RESULTS: 24 out of the 207 severely injured patients were transferred to other hospitals after stabilisation because of lack of room. Of the remaining 183 patients 124 had an ISS > or = 18.44 (35%) patients died during their stay in hospital. 21 (48%) of them died within 2 hours. 28 (64%) multiple injury patients died during the first 24 hours after admission. Neurological damage was the main cause of death (59%), followed by exsanguination (30%). A traffic accident was the cause of the injuries in 61% and a fall or jump in 27%. The mean ISS of these patients was 29 and the maximum score was 66. Head and neck injuries were present in 80% of the patients. The codification of brain damage by the MCD resulted in several mistakes. Brain damage in multiple injury cases results in a high AIS. Since the ISS is calculated by multiplication of AIS values, small differences in AIS create considerable variations in ISS. CONCLUSION: Multiple injury patients need fast and adequate help because of the high mortality, especially in the first 24 hours. The diagnostic codification of the MCD was found not reliable enough to be used for a hospital identification and registration of multiple injury patients.

Abbreviated Injury Scale↗
PubMed1994

Long-term in vivo study of plasma-sprayed coatings on titanium alloys of tetracalcium phosphate, hydroxyapatite and alpha-tricalcium phosphate.

In order to study the interaction of calcium phosphate coatings with bone tissue, coated titanium plugs of standard size were implanted in dog femora. The bone bonding and bone formation of hydroxyapatite, alpha-tricalcium phosphate (alpha-TCP) and tetracalcium phosphate plasma-sprayed coatings were evaluated by mechanical push-out tests and histological observations after 3, 5, 15 and 28 months of implantation. During this time all coating types degraded. alpha-TCP showed the most significant degradation after 3 months of implantation. Hydroxyapatite and tetracalcium phosphate showed significant signs of degradation after about 5 months of implantation. All coatings showed a small increase in bone bonding after 5 months of implantation. In general, all types of implants showed similar bone response, some bone contact and several remodelling lacunae along the surfaces after long-term implantation.

Alloys↗
PubMed1994

Loss of bone in the proximal part of the femur following unstable fractures of the leg.

We evaluated the subsequent loss of bone from the proximal part of the ipsilateral and contralateral femora and from the lumbar spine of seven men and nine women who had a fracture of the tibia. The average age was sixty years. All of the fractures were unstable, and the involved leg bore no weight for an average of eight weeks. The bone mineral density was measured with dual-energy x-ray absorptiometry of the lumbar spine and of the femoral neck and the trochanteric region of both hips immediately after the fracture, after the period of immobilization, and at approximately three, six, and twelve months after the fracture. During the period of immobilization, the bone mineral density of the trochanteric region decreased an average of 9 +/- 7 per cent on the side of the fracture, compared with the value immediately after the fracture, but there was no change on the contralateral side (p < 0.01). At twelve months, the average decrease in the trochanteric area was 15 +/- 10 per cent on the side of the fracture, compared with the value immediately after the fracture, but again there had been no change on the uninjured side (p < 0.01). The bone mineral density of the femoral neck on the side of the fracture had decreased 6 +/- 6 per cent at twelve months, compared with a decrease of 2 +/- 4 per cent on the uninjured side (p < 0.05). The bone mineral density of the lumbar spine decreased only during the period of unloading of the fractured leg (1 +/- 2 per cent, p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

[Cost effectiveness of preventive antibiotic administration for lowering risk of infection by 0.25%].

Antibiotic prophylaxis in closed fractures is cost-effective if the risk of a deep infection is reduced by 0.25%. This control study was undertaken to assess the cost-effectiveness of prophylaxis of postoperative infections after surgical treatment of closed fractures. The costs for 16 patients with infections (8 with deep infections, 8 with superficial infections) were investigated and compared with the costs for 16 similar but non-infected patients with special reference to length of hospital stay, antibiotics and surgery. The data were collected from the trauma department of the University Hospital of the Free University in Amsterdam. Costs in the group of 8 patients with superficial wound infection were not substantially higher than those for their non-infected controls. The occurrence of a deep infection meant costs an average of DFL 35,224 higher than an uneventful postoperative course. On the basis of these results, antibiotic prophylaxis of postoperative wound infections is cost-effective if it reduces the risk of deep wound infections by about 0.25%.

Adult↗
PubMed1994

Hemiarthroplasty in elderly, debilitated patients with an unstable femoral fracture in the trochanteric region.

The purpose of this study was to evaluate the results of patients with an unstable fracture in the trochanteric region who were treated by hemiarthroplasty. During a 10-year period, 154 of the 308 patients with a trochanteric fracture treated in our hospital had an unstable fracture. In patients with severe comminution and osteoporosis an endoprosthesis was inserted: 5 patients with a subtrochanteric and 17 with a pertrochanteric fracture. Ten patients suffered from central nervous system diseases, and in 10 patients cardiovascular or pulmonary disorders were diagnosed. Pre- and postoperative ambulation levels were classified. Seventeen patients (77%) achieved full weight-bearing mobilization. Five patients never walked again (23%): 2 patients died in the first month (9%). It is concluded that for elderly and debilitated patients with an unstable trochanteric fracture, hemiarthroplasty is an acceptable alternative to osteosynthesis.

Activities of Daily Living↗
PubMed1993

[Antibiotic prophylaxis in closed fractures is cost-effective if the possibility of a deep infection decreases through this by 0.25%].

This patient-control study was undertaken to assess the cost-effectiveness of prophylaxis of postoperative infections after surgical treatment of closed fractures. The costs of 16 patients with an infection (8 with deep infections, 8 with superficial infections) were investigated and compared with the costs of 16 similar noninfected patients for the parameters hospital stay, antibiotics and surgery. The data were collected from the trauma department of the University Hospital of the Free University of Amsterdam. There were no substantial extra costs in the group of the 8 patients with superficial wound infection compared with their noninfected controls. The mean extra costs for a deep infection in the other 8 patients were Dfl 35,224.-. Considering these results, antibiotic prophylaxis of postoperative wound infections is cost-effective, if it leads to a decrease of the risk of deep wound infections by about 0.25%.

Anti-Bacterial Agents↗
PubMed1993

Scoring multitrauma patients: which scoring system?

Two methods of estimating the severity of injury and evaluating outcome, the Injury Severity Score (ISS) and the Polytrauma-Schlussel (PTS), were evaluated. The records of 37 victims of multiple injuries were assessed retrospectively by nine trauma surgeons using both methods of scoring. The agreement among the users was calculated by standard deviation. The standard deviation (SD) among users was smaller for the PTS (4.1) than for the ISS (6.2). Each method of scoring comprises six components contributing to the total score. The three highest scoring components of the ISS were first squared and then summated, the sum being the total ISS score. All the PTS categories were summated. Comparison of the SD for each of the components was not possible. However, the category or categories which mostly influenced the standard deviation could be indicated. For the ISS these were the circulation and central nervous system and for PTS, the limbs. We prefer the Polytrauma-Schlussel method because this takes account of age, needs revision of only one category and gives more consistent results among users.

Accidents, Traffic↗
PubMed1992

Vascular injury from external fixation: case reports.

The incidence of vascular injury from external fixation of fractures was studied retrospectively in two surgical departments during the period 1985-1990. A total of 1231 fractures of the lower limb were treated. External fixation was used in the initial stabilization of 28 femoral and 93 tibial fractures. In this series of 121 fractures four iatrogenic vascular injuries were seen: two arterial thromboses with distal ischemia and two incidents of the formation of a false aneurysm with bleeding along a pin. The diagnosis was made by angiography. Surgical intervention was necessary in all four cases. In one patient the injury resulted in amputation of the distal portion of the foot.

Adult↗
PubMed1992

Retrosternal dislocation of the clavicle.

Retrosternal dislocation of the clavicle is an uncommon injury which may affect the mediastinal structures in a life-threatening way. Therefore, computed tomography is mandatory. Manipulation in the acute situation is the treatment of choice. In case of failure or old dislocation, open reduction with stabilization of the joint is required. The literature on this subject has been reviewed and an additional two cases are reported.

Adult↗
PubMed1991

Plasma-sprayed coatings of tetracalciumphosphate, hydroxyl-apatite, and alpha-TCP on titanium alloy: an interface study.

In order to study the interaction of calcium phosphate coatings with bone tissue, coated titanium cylinders with a standard size were implanted in dog femora. Coatings were made by plasma spraying powders of hydroxylapatite, beta-whitlockite, and tetracalciumphosphate particles. The plasma spraying process turns beta-whitlockite into alpha-TCP. Bone bonding and bone formation were evaluated by mechanical push-out tests and histological observations. Hydroxylapatite and tetracalciumphosphate coatings show an interface strength after 3 months of implantation of 34.3 +/- 6.5 MPa and 26.8 +/- 3.9 MPa, respectively, while alpha-TCP and blanco titanium lead to an interface strength of 10.0 +/- 3.5 MPa and 9.7 +/- 1.3 MPa, respectively. Histological examinations revealed that hydroxylapatite and tetracalciumphosphate give rise to an excellent bone formation, while alpha-TCP and blanco titanium evoked remodeling and less bone contact.

Alloys↗