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Meir Nyska

Publications and source records attributed to Meir Nyska.

At least 19 recordsLinked to original sources
PubMed2006

Gentamicin extended release from an injectable polymeric implant.

Gentamicin sulfate, a potent antibiotic agent, is currently used for treatment of osteomyelitis mainly by intravenous injection with a long-term indwelling catheter, local implant of antibiotic containing polymethylmethacrylate beads or calcium phosphate (bone cements). Searching for more effective treatments, this study was designed to evaluate biodegradable injectable gelling polymeric devices for the controlled release of gentamicin sulfate in the treatment of invasive bacterial infections. Gentamicin sulfate was incorporated in poly(sebacic-co-ricinoleic-ester-anhydride P(SA-RA)) paste at 10-20% w/w and its release in buffer solution was monitored. The in vitro activity of the formulations was determined against Staphylococcus aureus. A constant release of active gentamicin for over 28 days was found. The stability of the formulation was determined under different storage conditions. The formulations were stable to sterilization by gamma-irradiation and long term storage under freezing. The toxicity of the polymer and the formulations with gentamicin was examined by subcutaneous injection to rats. Four weeks after implantation, histopathological examination of the tissues surrounding the implant showed no inflammation. A preliminary study revealed positive effect of gentamicin containing P(SA-RA) on established osteomyelitis in a rat model. In conclusion this study suggests that poly(sebacic-co-ricinoleic-ester-anhydride) 3:7 loaded with 10%-20% gentamicin sulfate, might be used as an injectable biodegradable device for in situ treatment of osteomyelitis induced by S. aureus.

Animals↗
PubMed2006

The effect of muscle fatigue on in vivo tibial strains.

Stress fracture is a common musculoskeletal problem affecting athletes and soldiers. Repetitive high bone strains and strain rates are considered to be its etiology. The strain level necessary to cause fatigue failure of bone ex vivo is higher than the strains recorded in humans during vigorous physical activity. We hypothesized that during fatiguing exercises, bone strains may increase and reach levels exceeding those measured in the non-fatigued state. To test this hypothesis, we measured in vivo tibial strains, the maximum gastrocnemius isokinetic torque and ground reaction forces in four subjects before and after two fatiguing levels of exercise: a 2km run and a 30km desert march. Strains were measured using strain-gauged staples inserted percutaneously in the medial aspect of their mid-tibial diaphysis. There was a decrease in the peak gastrocnemius isokinetic torque of all four subjects' post-march as compared to pre-run (p=0.0001), indicating the presence of gastrocnemius muscle fatigue. Tension strains increased 26% post-run (p=0.002, 95 % confidence interval (CI) and 29% post-march (p=0.0002, 95% CI) as compared to the pre-run phase. Tension strain rates increased 13% post-run (p=0.001, 95% CI) and 11% post-march (p=0.009, 95% CI) and the compression strain rates increased 9% post-run (p=0.0004, 95% CI) and 17% post-march (p=0.0001, 95% CI). The fatigue state increases bone strains well above those recorded in rested individuals and may be a major factor in the stress fracture etiology.

Adult↗
PubMed2006

Scoring systems for evaluating ankle function.

Each of the seven systems described has advantages and drawbacks that consist of ease or difficulty of application, accuracy, validity, and availability. This article should contribute to make these systems better known and easier to apply, and thus, will encourage their use in clinical practice. [Fig.: see text].

Ankle↗
PubMed2005

The role of sonography in detecting radial head subluxation in a child.

Injuries around the elbow joint in children can be difficult to diagnose on the basis of findings on physical examination and radiographs. We present the case of a 4-year-old girl with a probable subluxation of the radial head, based on the findings on physical examination and radiographs. Radiography raised the possibility of a radial head subluxation. Sonography demonstrated displacement of the cartilaginous head of the radius away from the capitellum in the affected elbow. The child underwent corrective surgery. During fluoroscopy, results of an ulnar stress test were positive for lateral ligament tears. The patient's arm was put in a cast for 6 weeks. At 1-year follow-up, the patient had full range of motion of the elbow without pain. We present the findings of sonographic studies used to confirm the diagnosis.

Accidental Falls↗
PubMed2005

2-Butoxyethanol female-rat model of hemolysis and disseminated thrombosis: X-ray characterization of osteonecrosis and growth-plate suppression.

We recently proposed a chemically induced rat model for human hemolytic disorders associated with thrombosis. The objective of the present investigation was to apply a noninvasive, high-magnification X-ray analysis, the Faxitron radiography system, to characterize the protracted bone damage associated with this 2-butoxyethanol model and to validate it by histopathology. Groups of female Fischer 344 rats were given 0, 250, or 300 mg of 2-butoxyethanol/kg body weight daily for 4 consecutive days. Groups were then sacrificed 2 hours or 26 days after the final treatment. The treated animals displayed a darkened purple-red discoloration on the distal tail. Histopathological evaluation, including phosphotungstic acid-hematoxylin staining of animals sacrificed 2 hours after the final treatment, revealed disseminated thrombosis and infarction in multiple organs, including bones. The Faxitron MX-20 specimen radiography system was used to image selected bones of rats sacrificed 26 days posttreatment. Premature thinning of the growth plate occurred in the calcaneus, lumbar and coccygeal vertebrae, femur, and ilium of the treated animals. Areas of decreased radiographic densities were seen in the diaphysis of the femur of all treated animals. The bones were then examined histologically and showed a range of changes, including loss or damage to growth plates and necrosis of cortical bone. No thrombi were seen in the animals sacrificed at 30 days, but bone and growth plate changes consistent with prior ischemia were noted. The Faxitron proved to be an excellent noninvasive tool that can be used in future studies with this animal model to examine treatment modalities for the chronic effects of human thrombotic disorders.

Animals↗
PubMed2005

The medial longitudinal arch as a possible risk factor for ankle sprains: a prospective study in 83 female infantry recruits.

BACKGROUND: Ankle sprains are frequent, especially in athletes, soldiers, or others who perform high levels of physical activity. Although prevention is a primary goal, little is known about the risk factors. We evaluated the association of the structure of the medial arch of the foot to the occurrence of acute and recurrent ankle sprains in 83 female infantry recruits. We found no previous studies on ankle sprains in women in the English literature. METHODS: Arch height was quantified using the Chippaux-Smirak index, and each arch was classified as high, normal, or low. Retrospective data were obtained from questionnaires in which the soldiers noted whether or not they had had ankle sprains in the past, the grade of the sprain, and recurrence. Prospective data were accumulated in the 4 months of basic training, during which time every ankle sprain was documented and classified according to its grade and cause. RESULTS: The retrospective data showed more frequent ankle sprains in the low arch group than in the normal arch group, mainly in the right foot (RR of 2.9, p <0.05). Recurrent sprains studied retrospectively also showed that more sprains occurred in the low arch group than in the normal arch and high arch groups (RR of 10.3, p <0.05). The prospective data suggested a pattern toward the same outcome (50% in the low arch as opposed to 36% in the normal arch group, RR, 1.3), but with no statistical significance. CONCLUSIONS: We concluded that a low arch of the foot might be a risk factor for ankle sprains. However, our study consisted of a relatively small population, and further studies are needed.

Acute Disease↗
PubMed2005

Isokinetic strength and endurance after percutaneous and open surgical repair of Achilles tendon ruptures.

BACKGROUND: Reports on complete spontaneous Achilles tendon ruptures and associated treatment have become more frequent in the literature in the past two decades, as has the request for treatments that enable the finest possible functional recovery. The best available treatment is a matter of considerable controversy in the literature. The purpose of this study was to compare the isokinetic strength and endurance of the plantarflexor muscle-tendon unit in subjects who sustained rupture of the Achilles tendon and underwent either open surgery or closed percutaneous repair of the Achilles tendon. METHODS: Twenty patients (18 males, 2 females) with spontaneous ruptures of the Achilles tendon were included in this study. Ten patients were treated by open surgery, and 10 patients were treated percutaneously. All patients had ruptured their Achilles tendon more than 6 months before the study, and all of the ruptures occurred 3.5 years or less before the day of the testing. All patients underwent an oriented physical examination. An isokinetic Biodex dynamometer (Biodex Medical System, Shirley, NY) was used to measure ankle joint angle, and in plantarflexion to calculate the torque at the ankle joint (Newton/meter), and the average work (jouls) for both maximal power and endurance. Each measurement was compared to the normal ankle. RESULTS: Biodex dynamometer evaluations at 90 deg/sec demonstrated a significant difference of maximal voluntary plantarflexor torque, endurance performance and range of motion at the ankle joint between the involved and uninvolved sides in patients treated by either mode of treatment. Yet, no statistically significant differences were revealed for the parameters mentioned above between the subjects that were treated either percutaneously or by an open surgery. CONCLUSIONS: In functional terms, the biomechanical outcomes of open surgery and percutaneous repair for acute ruptures of the Achilles tendon are both effective.

Achilles Tendon↗
PubMed2005

Ipsilateral fibular transfer for a large tibial defect caused by a gunshot injury: case report.

Segmental bony defects in open fractures of the tibia are bridged with bone grafting, free vascularized fibular grafts, or an external ring fixator. A 33-year-old man sustained a gunshot injury to his left leg, resulting in Gustillo type IIIB open fractures of the tibia and fibula. The tibia had a segmental massive defect of 19 cm in the midshaft. Debridement and immediate application of an Ilizarov external fixator were performed. The midportion of the ipsilateral fractured fibula served as a bridging vascularized graft for the tibial defect. Good bony union and fibular hypertrophy were obtained. Use of a fractured fibula from a zone previously injured by a gunshot has not been reported. This case demonstrates the successful transfer of a fractured fibula for the bridging of an ipsilateral tibial defect caused by a gunshot injury.

Adult↗
PubMed2004

Motion-based tendon diagnosis using sequence processing of ultrasound images.

Degenerative or pre-degenerative processes in the tendon, which could lead to a spontaneous rupture, are well known problems, especially among athletes. Existing non-invasive diagnostic methods are mainly based on subjective analysis of static images of the tendon, but in many cases the degeneration cannot be diagnosed in time. Combining a set of existing image processing techniques, a tool for tracking the in vivo motion of a tendon imaged with dynamic ultrasound was implemented. A group of subjects that had undergone a degenerative rupture of their Achilles tendon, one subject with a traumatic rupture, and a group of control subjects were all tested. Using the motion information that was obtained from both tendons of all subjects, we developed an automatic test that examines the symmetrical properties of the tendon's motion, and defined a negative asymmetry property that could be quantified as a score. This score was found to be significantly more enhanced in the post-operative tendons (18.0 +/- 9.0) than in the contra-lateral healthy tendons of the same subjects (3.9 +/- 4.6). In the single traumatic rupture subject, this effect was not found (0.0). This leads us to believe that the negative asymmetry of tendon motion may be associated with degenerative or pre-degenerative processes in the tendon. Also, the mean degree of negative asymmetry in the healthy tendons of post-operative subjects (3.9 +/- 4.6) was found to be higher than that of healthy tendons of the control group (1.5 +/- 1.8). This finding may be associated with the fact that tendons that are contra-lateral to spontaneously ruptured tendons have a higher risk of developing degenerative processes. The method presented here is objective, low-cost, non-invasive and possibly more sensitive than existing non-invasive techniques.

Achilles Tendon↗
PubMed2003

2-Butoxyethanol enhances the adherence of red blood cells.

We recently presented a unique, chemically-induced rat model of hemolytic anemia and disseminated thrombosis. In this 2-butoxyethanol (BE)-induced model the organs developing infarction are comparable to those seen in human diseases, characterized by hemolysis and thrombosis (e.g., thalassemia, sickle-cell disease, paroxysmal nocturnal hemoglobinuria, disseminated intravascular coagulation, thrombotic thrombocytopenic purpura, and hemolytic uremic syndrome). Red blood cells (RBCs) have special flow properties, namely, self-aggregability, deformability, and potential adherence to endothelial cells (ECs) of the blood vessel wall, which are essential for adequate blood flow and tissue perfusion; their alteration facilitates circulatory disorders. To examine the possible contribution of alterations in RBC flow properties to the observed thrombosis in the present investigation we determined the BE-induced changes in adherence, aggregability, and deformability of RBCs from male and female Fischer F344 rats exposed to two, three, or four daily doses of BE at 250 mg BE/kg body weight. Control animals were treated with the vehicle alone. Blood was taken on days 2, 3, 4, and 29. The administration of BE did not affect the RBCs aggregability but markedly enhanced their adherence to extracellular matrix; such enhancement was correlated with adherence to cultured ECs. RBC/EC interaction has been shown to be a potent catalyst of vascular occlusion in hemolytic hemoglobinopathies; thus the enhanced RBC adherence to EC is a likely mechanism by which thrombosis and organ infarct are induced in BE-treated rats.

Administration, Oral↗
PubMed2003

Ocular expression of vascular cell adhesion molecule (VCAM-1) in 2-butoxyethanol-induced hemolysis and thrombosis in female rats.

We demonstrated previously that exposure of rats to 2-butoxyethanol (BE) was associated with morphological changes in red blood cells, hemolytic anemia, and disseminated thrombosis and infarction in different organs including the eyes. In order to elucidate the mechanism of thrombosis formation, we examined in this study the histology and immunohistochemical expression of vascular cell adhesion molecule-1 (VCAM-1), endothelial intercellular adhesion molecule-1 (ICAM-1), and P-selectin in the eyes of the female F344 rat exposed to 2, 3, or 4 daily doses of BE/250 mg/kg body weight. In this BE hemolysis and thrombosis model, positive VCAM-1 expression occurred only in eyes of rats exposed to 3 and 4 doses and was localized in the iris (epithelium lining the posterior surface, anterior mesenchymal epithelium), ciliary processes (lining epithelium, stromal cells), and retina (hypertrophic retinal pigment epithelium). Only weak immunolabeling was seen in eyes exposed to 2 doses. The appearance of VCAM-1 immunostaining correlated with the development of thrombosis located in the same structures. No change in ICAM-1 or P-selectin expression was seen. This immunolabeling distribution suggests that VCAM-1 functions in the pathogenesis of BE-related thrombosis by promoting adhesion of erythrocytes to the endothelium.

Animals↗
PubMed2003

The second hip fracture--an analysis of 84 elderly patients.

OBJECTIVES: Evaluation of patients with a second hip fracture, which means a fracture of the contralateral hip. DESIGN: Retrospective database analysis. SETTINGS: Academic teaching hospital. PATIENTS: All patients who were admitted for their second hip fractures between November 1999 and September 2001 and had their first hip fracture treated in our institution. INTERVENTION: In this study, we epidemiologically analyzed the fracture types, the interval between the two fractures, general status of the patients, type of operation performed, and the postfracture independence level. RESULTS: This survey comprises 84 patients (65 females and 19 males). Their ages ranged from 57 to 91 years (mean: 79) and 58 to 93 years (mean: 82) for the first and the second operation, respectively. The interval between the operations ranged from 2 to 297 months (mean: 35 months, median: 30 months). Twenty-three patients had subcapital fractures in both hips. In 54 patients, bilateral intertrochanteric fractures were noted. Only 7 patients had a previous subcapital fracture and a second intertrochanteric fracture. The general status of the patients' health was defined by the number of pre-existing major medical conditions and was found to be between 0 and 4 (mean: 2.15). Thirty-two patients (38%) had additional fractures somewhere between 1 and 8 years prior to the hip fracture (vertebra, proximal humerus, or distal radius). Sixty-eight and 56 out of the 84 patients reached the same mobility status after the first and second operation, respectively. CONCLUSIONS: A tendency was found for the second hip fracture to be of the same type as the previous one. Most patients showed a good potential for rehabilitation and for maintaining their prefall functional level.

Activities of Daily Living↗
PubMed2003

The Ludloff metatarsal osteotomy: guidelines for optimal correction based on a geometric analysis conducted on a sawbone model.

Ideally, osteotomy for hallux valgus deformities corrects varus angle and pronation, while minimizing elevation, depression, and shortening. We used a serial linkage tracking device to evaluate five variations of the Ludloff osteotomy, a stable proximal metatarsal osteotomy that incorporates an oblique dorsal to plantar cut and a lateral swing or pivoting correction of the dorsal fragment. A neutral osteotomy (perpendicular to the sagittal plane) yielded the greatest correction (14 degrees) but with shortening (average, 2.85 mm), elevation (average, 1.36 mm), and additional pronation (average, 1.88 degrees). The same osteotomy angled 10 degrees plantarly with 8 degrees of correction produced an average of 1.57 degrees of supination, 1.22 mm of depression and, 0.54 mm of shortening. Additional plantar inclination (20 degrees) and angular correction (16 degrees) yielded increased depression, supination, and shortening. The current findings provide guidelines to achieve the desired correction and rotation and suggest that optimal results can be obtained by performing this osteotomy angled 10 degrees plantarly with a correction of 8 degrees to 16 degrees.

Hallux Valgus↗
PubMed2003

Outcome of resection of a symptomatic os trigonum.

BACKGROUND: While an os trigonum at the posterolateral aspect of the talus is usually asymptomatic, this inconsistently present accessory bone has been associated with persistent posterior ankle pain, which has been described as the os trigonum syndrome. We present the clinical results of excision of the os trigonum through a posterolateral approach and report several factors affecting the clinical outcome. METHODS: During a five-year period from 1994 through 1999, forty-one patients had a failure of nonoperative treatment of os trigonum syndrome and underwent excision of a symptomatic os trigonum. In all cases, the os trigonum syndrome was diagnosed on the basis of the history, physical examination, and radiographs. Postoperatively, the patients were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. A questionnaire was used to evaluate the effect of several factors on the clinical outcome. RESULTS: The average duration of follow-up was forty-four months. The postoperative AOFAS score averaged 87.6 points. The thirty-three patients who had had symptoms for two years or less prior to the surgery had an average postoperative score of 90 points compared with 78 points for the eight patients who had had preoperative symptoms for more than two years (p = 0.011). Eight patients had sural nerve sensory loss, which was temporary in four and permanent in four. A superficial wound infection developed in one patient, and reflex sympathetic dystrophy developed in another. CONCLUSIONS: An os trigonum that is persistently symptomatic after a minimum three-month trial of nonoperative treatment can be excised through a posterolateral approach with highly satisfactory results. The main complication of this procedure is sural nerve injury.

Adolescent↗
PubMed2003

Economic consequences of operative delay for hip fractures in a non-profit institution.

This retrospective study evaluated the economic consequences of delaying hip fracture surgery in 191 elderly patients. Data was collected regarding fracture type, surgery, timing of surgery, background diseases, postoperative hospital stay, and complications. In addition, calculation of the drugs administered to the patients, cost of the surgery, blood transfusion, physiotherapy, laboratory examinations, radiographs, and any financial data were evaluated. Spending more resources for performing hip surgery within 48 hours is more cost-effective than delaying surgery past the third day.

Aged↗