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Biomedical subjects

A S Levy

Publications and source records attributed to A S Levy.

At least 19 recordsLinked to original sources

Effect of displacement of fractures of the greater tuberosity on the mechanics of the shoulder.

Using a dynamic biomechanical model of malunion of the shoulder, we have determined the change in deltoid force required for abduction with various combinations of superior and posterior displacement of fractures of the greater tuberosity of the humerus. We tested eight fresh human cadaver shoulders in a dynamic shoulder-testing apparatus during cycles of glenohumeral abduction from 0 degrees to 90 degrees. The greater tuberosities were osteotomised and stabilised to represent malunion with combinations of superior and posterior displacements of 1 cm and less. The peak force was measured for each displacement in each specimen and statistically compared with values of no displacement using a repeated-measures analysis of variance. The abduction force was significantly increased by 16% (p = 0.006) and 27% (p = 0.0001) by superior displacements of 0.5 cm and 1 cm, respectively, while combined superior and posterior displacement of 1 cm gave an increase in force of 29% (p = 0.001). While treatment criteria for acceptable residual displacement of the greater tuberosity are widely used, there is little information on the direct biomechanical effects of displacement on shoulder mechanics. Although the results of conservative treatment are influenced by a number of factors, including associated injuries, rehabilitation and the pre-existing function of the shoulder, our data suggest that small amounts of residual displacement may alter the balance of forces required to elevate the arm at the glenohumeral joint.

Adult↗

Ewing's sarcoma.

Patients with Ewing's sarcoma should be transferred to a comprehensive cancer center for evaluation and management when the diagnosis is suspected. Proper biopsy technique is essential to preserve all therapeutic options, including limb preservation surgery. In addition to conventional histologic examination, biopsy tissue must be obtained for molecular biology studies. Demonstration of the consistent chromosomal translocation associated with Ewing's sarcoma is essential for diagnosis, and the specific type of fusion transcript has prognostic implications. Treatment must be intimately coordinated among oncologist, surgeon, and radiation oncologist. Successful treatment requires systemic, multi-agent chemotherapy and local control. The primary tumor can be treated with surgery, radiation therapy, or a combination of the two. The choice of modality should be dictated by the age of the patient, location of the primary tumor, functional consequences of the intervention, and concern about late effects, especially secondary malignancy. Treatment of the patient who presents with clinically detectable metastatic disease or who relapses after initial therapy remains unsatisfactory and controversial.

Antineoplastic Agents↗

Neurologic injuries in skiers and snowboarders.

Neurologic injures are the leading cause of death and disability in skiing and snowboarding accidents, despite accounting for only a small fraction of injuries overall. Head injuries make up 3 to 15% of all skiing and snowboarding related injuries, spinal injuries account for 1 to 13%, and peripheral nerve injuries constitute less than 1% of reported injuries. Improvements in equipment and technology, especially advances in binding technology, have resulted in decreased injury rates on the slopes overall, but neurologic injury rates have not decreased, and in fact appear to be increasing as a percentage of overall injuries and in absolute numbers. With advances in technology and slope maintenance, skiers and boarders progress to higher skill levels and faster speeds more rapidly than ever before. Great efforts have been focused on reducing extremity injuries in skiers and snowboarders, but until recently very little attention has been given to neurologic injury prevention on the slopes. Hopefully with increased awareness and the growing popularity of ski/snowboard helmets, we will begin to see head injury rates (and maybe even spine injury rates) decrease among skiers and snowboarders.

Accident Prevention↗

Internal derangement of the knee after ipsilateral femoral shaft fracture: MR imaging findings.

OBJECTIVE: This study uses magnetic resonance (MR) imaging to delineate the types and frequencies of injuries seen in the knee after ipsilateral femoral shaft fracture. We also compare the results of the orthopedic knee examination with the MR findings. DESIGN AND PATIENTS: MR imaging of the ipsilateral knee was performed on 34 patients with closed femoral shaft fractures. Indications for knee MR imaging included knee pain at the time of fracture, soft tissue swelling or an effusion of the knee, or a positive knee examination under anesthesia. The patients had a mean age of 27 years and all were stabilized with intramedullary nails. Imaging was performed a mean time of 2.5 days after surgery. All patients had knee examinations done under anesthesia, and the MR results were compiled and compared with the clinical examinations. RESULTS: Ninety-seven percent of patients demonstrated knee effusions. Twenty-seven percent of patients demonstrated meniscal tears, with the posterior horn of the medial meniscus most frequently torn. The medial collateral ligament was the most frequent site of ligamentous injury (38%) followed by the posterior cruciate ligament (21%). Fifty percent of patients had injuries of the extensor mechanism. Bone bruises were noted in 32% of patients. Articular cartilage injuries were confined to the patella in four cases. One occult tibial plateau fracture and one meniscocapsular separation were seen. CONCLUSIONS: There is a common incidence of both ligamentous and meniscal injury to the knee after ipsilateral femoral shaft fracture. MR imaging can be useful in assessing the extent of injury, and may reveal findings unsuspected after clinical examination of the knee.

Adult↗

Cavernous angiomas of the cauda equina: case report and review of the literature.

BACKGROUND: Cavernous hemangiomas of the spine and spinal cord are relatively uncommon lesions that are being discovered more frequently because of the increased use of magnetic resonance imaging (MRI). We present a rare case of a symptomatic cavernous hemangioma of the cauda equina. CASE DESCRIPTION: A 49-year-old woman presented to our institution with the chief complaint of low back pain of acute onset. On physical examination the patient was found to be tender to percussion over the lumbar spine, had tenderness over the sciatic nerve, loss of pinprick sensation over the right lateral foot and loss of the Achilles' reflex on the right. In addition, she was found to have a large postvoid urinary bladder residual volume. MRI revealed a 20 mm x 11 mm nonenhancing, heterogenous mass obliterating the spinal canal at the L4 level. At operation, this lesion was found to be adherent to the nerve roots and was completely resected. Pathology revealed this lesion to be a cavernous angioma of the cauda equina. A review of the pertinent literature is presented. CONCLUSIONS: Cavernous hemangiomas of the cauda equina are extremely rare lesions that may present as low back pain, neurologic deficit, or as subarachnoid hemorrhage. They can be successfully treated with surgical excision.

Adult↗

Effect of a ketoacid-aminoacid-supplemented very low protein diet on the progression of advanced renal disease: a reanalysis of the MDRD feasibility study.

BACKGROUND: We reanalyzed the data of the Modification of Diet in Renal Disease (MDRD) feasibility study to ascertain the effects of ketoacid- and aminoacid-supplemented very low protein diets. METHODS: Sixty-six patients with advanced renal disease (Study B, baseline glomerular filtration rate (GFR) 7.5-24 ml/min/1.73 m2) were randomly assigned to a low protein diet (L, 0.575 g/kg/d), or a very low protein diet (0.28 g/kg/d) supplemented either with a ketoacid-aminoacid mixture (diet K) or with a mixture of essential aminoacids (diet J). Thirty patients with moderate renal disease (Study A, baseline GFR 25-80 ml/min/1.73 m2) were randomly assigned to a usual protein diet (M, 1.2 g/kg/d), diet L, or diet K. Mean follow-up was 14 months. RESULTS: In Study B, GFR decline differed among the three diets (p = 0.028). Pairwise comparisons showed that the mean +/- SE GFR decline in ml/min/mo in diet K [-0.250+/-0.072] was slower than in diet J [-0.533+/-0.074] (p = 0.008) despite similar achieved protein intakes. The mean GFR decline in diet L [-0.394+/-0.068] was intermediate between, and did not differ significantly from the rates of decline in the other two groups. In Study A, consistent with a hemodynamic effect, the mean GFR decline varied directly with the reduction in protein intake in diets M, L and K (p = 0.028) during the first four months of follow-up, but thereafter did not differ among the diet groups (p = 0.76). CONCLUSION: The study suggests that supplementation of a very low protein diet with the ketoacid-aminoacid mixture used in this feasibility study slowed the progression of advanced renal disease more than supplementation with an amino acid mixture.

Adult↗

Penetration of cryotherapy in treatment after shoulder arthroscopy.

Fifteen patients undergoing shoulder arthroscopy had indwelling temperature probes placed in the glenohumeral and subacromial spaces. All shoulders underwent diagnostic arthroscopy and debridement of the subacromial space. Cryotherapy was delivered to the shoulder via a Cryo/Cuff (AirCast, Summit, NJ) and temperatures were monitored for 90 minutes. Ten shoulders received cryotherapy and 5 were used as controls. Before cryotherapy, temperature averaged 34 degrees C in the glenohumeral joint and 31 degrees C in the subacromial space. No significant difference was seen between the temperatures recorded in the cold therapy and control groups for either the glenohumeral or subacromial space. In all cases, the subacromial space averaged 1 degree cooler than the glenohumeral joint at the conclusions of arthroscopy. These slowly equalized to an average of 35 degrees postoperatively. The present study shows that surface-applied cryotherapy does not penetrate either the glenohumeral joint or the subacromial space. Attention must be turned elsewhere to delineate how cryotherapy works.

Adult↗

The orthopedic and social outcome of open tibia fractures in children.

To determine whether the accepted principles of management of open tibia fractures apply to children, 40 consecutive open fractures of the tibial shaft in skeletally immature patients were retrospectively reviewed. Attempts were made to evaluate the functional and social impact of open tibia fractures in children. All open fractures were initially treated by rapid irrigation and debridement which was repeated every 48 hours until soft tissues stabilized. The average age was 10.1 years and average follow up was 26 months (range: 18 to 84). There were 16 grade I, 10 grade II, and 14 grade III open fractures. The grade III fractures were further subdivided into 6 grade IIIA, 7 grade IIIB, and 1 grade IIIC. The average time to union was 7.5 and 11.0 weeks in the grade I and II fractures respectively, with no infections and no delayed unions. In grade III fractures, the average time to union was 15 weeks, with 1 infection and 3 delayed unions. Bone grafting using autogenous iliac crest was performed on 2 patients. The children surveyed missed an average of 4.1 months of school and 33% had to repeat a year. Twenty-five percent of the children complained of nightmares involving the events of the accident. Chronic pain despite solid union was found in 30% of patients. Forty percent of those surveyed (7 grade III fractures) complained of a limp. The low incidence of soft tissue complications and infections in the study population supports applying in children the same basic soft tissue management principles of open fracture treatment as used in adults. While bone stabilization options are limited in children, the rate of successful union without adjunctive bone grafting is much higher than that of adults treated under similar protocols. Routine early iliac crest bone grafting is unnecessary. The prevalence of gait abnormality despite fracture union should be taken into account during the patient's rehabilitation. The extensive time missed from school and resulting scholastic setback should not be underestimated.

Adolescent↗

Consumer knowledge of foodborne microbial hazards and food-handling practices.

A national telephone survey was conducted of 1,620 randomly selected U.S. residents who spoke English, were at least 18 years old, and resided in households with kitchen facilities. Respondents were interviewed about their recognition of foodborne pathogens, foods at risk for transmitting infection, knowledge of safe food handling, and food-handling practices. One-third of the respondents who prepared meals reported unsafe food hygiene practices: e.g., they did not wash hands or take precautions to prevent cross-contamination from raw meat. Unsafe practices were reported more often by men, adults 18 to 29 years of age, and occasional food preparers than by women, persons 30 years old or older, and frequent food preparers. Respondents who identified a food vehicle for Salmonella spp. were more likely to report washing their hands and cleaning cutting boards after preparing raw meat and poultry. The results raise concerns about consumer food-handling practices. The influence of food safety training, food-handling experience, and age on food-handling practices should be studied further. Awareness of a food vehicle for Salmonella spp., for example, may indicate knowledge of the etiology of foodborne disease that promotes safe food handling. Understanding the factors associated with safe food handling will assist in development of effective safe-food instruction programs.

Adolescent↗

Subarachnoid neurocysticercosis with occlusion of the major intracranial arteries: case report.

Cysticercosis is the most common parasitic disease affecting the central nervous system. Stroke is a recognized complication of neurocysticercosis, occurring in 2 to 12% of cases, mostly in the form of small lacunar infarcts. We report a case of hemiparesis and aphasia in a 51-year-old Hispanic woman, which was secondary to complete occlusion of the left internal carotid and bilateral anterior cerebral arteries. Magnetic resonance imaging demonstrated the presence of enhancing subarachnoid material surrounding these occluded cerebral arteries, providing antemortem, noninvasive documentation of the inflammatory meningeal cysticercotic reaction that was presumably responsible for the occlusive arteritis causing the cerebral infarction. This represents the third reported case of internal carotid artery occlusion and the first reported case of anterior cerebral artery occlusion secondary to neurocysticercosis.

Brain Diseases↗

Tibia fractures produced from the impact of a baseball bat.

Forty-seven patients presented during a 1-year period with fractures of the extremities produced by the impact of a baseball bat. This represented an increase of fourfold in fractures associated with baseball bat trauma as compared with the previous year. Those patients with tibia fractures were retrospectively reviewed in terms of associated soft-tissue injuries, fracture pattern, and fracture healing. Potential force generated and kinetic energy transferred when a baseball bat strikes the tibia were calculated mathematically to provide correlation with clinical observations. Tibia fractures produced by baseball bats represented 10% of all tibia fractures presenting from July 1990-July 1991. Of these 11 tibia fractures, 3 developed compartment syndrome, necessitating fasciotomy and subsequent skin grafting, and 1 developed osteomyelitis, which eventually resulted in amputation. One patient had superficial skin blistering that required a delay in definitive fracture care of 11 days and subsequent skin grafting. There was one nonunion and three delayed unions requiring additional operative intervention. This incidence of compartment syndrome (27%) is nine times higher than the overall incidence, at this institution, of compartment syndrome (3%) in tibia fractures produced by other mechanisms. The maximum potential kinetic energy produced during the impact of a baseball bat is 515 kg/m2/s2: 25% higher than that produced by a 9-mm bullet fired at a distance of 6 ft (407 kg/m2/s2). The potential force transmitted from a bat to the tibia at the time of collision is 8,000 lb, three times that of the bullet (626 lb).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

The use of MRI in the diagnosis of occult hip fractures in the elderly: a preliminary review.

Establishing the diagnosis of a non-displaced hip fracture in an elderly patient can be a prolonged and costly procedure, involving hospital admission, several days of bed rest, and a bone scan 3 to 5 days later. The authors evaluated 10 hips in 10 patients with a questionable diagnosis of non-displaced hip fracture. Magnetic resonance imaging (MRI) soon after admission revealed four patients with acute hip fractures who were subsequently treated. The other six patients, whose scans were negative for either femoral neck or intertrochanteric fractures, were mobilized. The authors show that, through the use of an immediate MRI study of a questionable hip fracture, the prolonged recumbency and inherent costs associated with awaiting a positive bone scan can be avoided.

Aged↗

Weight control practices of U.S. adults trying to lose weight.

OBJECTIVE: To estimate the relative prevalence of different types and combinations of practices among weight-loss practitioners and to describe the relations between individual characteristics and various features of weight-loss regimens. DESIGN: A telephone survey of a random digit-dialed probability sample of adults in the continental United States who reported that they were trying to lose weight. PARTICIPANTS: A total of 1431 persons 18 years or older who were attempting to lose weight. MEASUREMENTS: Self-reports of a detailed inventory of more than 35 specific practices that might be used as part of a voluntary weight-loss plan, along with information about individual characteristics such as current weight, weight-loss history, demographic profile, motivations to lose weight, sources of information, and knowledge about diet and health. RESULTS: The average respondent had a current weight-loss attempt lasting from 5 to 6 months, had tried a similar plan before, and had averaged one attempt a year for the past 2 years. Seventy-one percent of women and 62% of men reported that they were both changing their diet and exercising more as part of a current weight-loss attempt. Frequently reported weight-loss practices included weighing oneself regularly (71% and 70% for women and men, respectively), walking (58% and 44%), using diet soft drinks (52% and 45%), taking vitamins and minerals (33% and 26%), counting calories (25% and 17%), skipping meals (21% and 20%), using commercial meal replacements, (15% and 13%), taking diet pills (14% and 7%), and participating in organized weight-loss programs (13% and 5%). Sex, education, and overweight status influenced the choice of a weight-loss practice. CONCLUSIONS: Individual approaches to weight-loss vary and are characterized by their duration and by their recurrent nature. Policy efforts should be directed toward increasing the long-term effectiveness of individual weight-loss plans.

Adolescent↗

The role of cold compression dressings in the postoperative treatment of total knee arthroplasty.

A prospective randomized study was performed to evaluate the role of cold compressive dressings in the postoperative treatment of total knee arthroplasty (TKA). Eighty consecutive unilateral and ten bilateral primary total knee replacements were evaluated in terms of blood loss, pain relief, and range of motion. Patients in the cold compression group demonstrated an average of 548 ml in suction drainage, whereas those in the control group averaged 807 ml. This resulted in an average 3.1 mg hemoglobin drop in the cold compression group and 4.7 mg in the control group. When body habitus and weight were taken into account in the cold compression group, an average total blood loss of 1298 cc was calculated, with 744 ml arising from soft tissue extravasation. The corresponding total blood loss calculated average was 1908 ml in the control group, with 1101 ml attributed to soft tissue extravasation. Total injectable morphine per kilogram per initial 48 hours averaged 0.53 mg in the cold compression patients and 0.69 mg in the control patients. In the cold compression knees, range of motion averaged 86 degrees before operation, 53 degrees on postoperative day (POD) 7, and 77 degrees on POD 14. In the control knees, range of motion averaged 88 degrees before operation, 44 degrees on POD 7, and 65 degrees on POD 14. The use of cold compression in the postoperative period of TKA results in a dramatic decrease in blood loss. In addition, mild improvements are seen in early return of motion and injectable narcotic pain needs in the postoperative period.

Aged↗

Treatment of open tibial fractures with Ender rods.

In a retrospective, nonrandomized study from 1980 until 1988, 43 patients with 46 open tibial fractures were treated with Ender rods. The configuration of each fracture was classified using the Orthopaedic Trauma Association's (OTA) tibial fracture guidelines, and the extent of soft-tissue damage was graded using the Gustilo classification of open fractures. The OTA classification was further divided into stable, unstable, and highly unstable fracture configurations. Ender rods were placed immediately into 90% of fractures; and within one week of initial injury in the remainder. Follow-up evaluation of four patients (six fractures) could not be completed. The average time to union was 22.1 weeks, and there was a low incidence of complications. Otherwise there was a 40% incidence associated with early rod removal. Most complications occurred in those fractures that had extensive soft-tissue damage, and minimal or no inherent axial stability (unstable and highly unstable OTA classes). Except for the above-noted complications, Ender rods provide effective fixation for open tibial fractures with some degree of axial and rotational stability. In fractures with minimal or no inherent axial stability (OTA Classes IIIC, D; IVA, B), and in Grade IIIB or IIIC open tibial fractures, Ender rods have a higher incidence of complications and should be used with caution.

Adult↗