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Biomedical subjects

L X Webb

Publications and source records attributed to L X Webb.

33 records · Page 2Linked to original sources

Unstable femoral shaft fractures: a comparison of interlocking nailing versus traction and casting methods.

Among 60 femur fractures not amenable to fixation by simple intramedullary nailing, 30 were treated with balanced skeletal traction followed by cast bracing or spica casting, and 30 were treated with closed interlocking nailing. The criteria for using an interlocking nail were fractures with less than 50% cortical contact or fractures with rotationally insecure purchase of the nail in either the proximal or distal fragment. In terms of fracture severity, patient age, injury severity, and clinical follow-up, the patient groups were similar. There were three open fractures in each group. The average hospital stay was 61 days for the traction group, and 19 days for the interlocking nail group (p less than 0.001). Time to clinical and radiographic union averaged 34 weeks with traction and casting and 18 weeks with interlocking nail fixation (p less than 0.001). Failure by the criteria of Johnson et al (2) occurred in 67% of the traction group and in 3% of the interlocking nail group (p less than 0.001). Minor complications were more common in the traction group. On the basis of this study and the experience of others, interlocking nail fixation appears to be the method of choice for managing unstable femoral shaft fractures.

Adolescent↗

Adhesive colonization of biomaterials and antibiotic resistance.

This study addresses the problem of antibiotic resistance in adhesive, biomaterial-centred infections. It is suggested that this anionic, extracapsular, polysaccharide slime produced by bacteria protects them from antibiotics and sequesters critical ions from the surface of biomaterials. Biofilm-enclosed bacteria on the surface of stainless steel substrata in a test chamber were challenged with incremental levels of tobramycin. In this setting, the minimum inhibitory concentration and minimum bactericidal level of tobramycin for Staphylococcus epidermis were well above normal.

Acrylic Resins↗

The crowded carpal sign in volar perilunar dislocation.

Three cases of volar perilunar dislocation were seen at North Carolina Baptist Hospital over a 6-year period. An important finding on anteroposterior radiographs was the overriding of proximal and distal carpal rows giving rise to the "crowded carpal" appearance. Review of the literature demonstrates this configuration in all illustrations of volar perilunar dislocation. Although some authors have noted its presence, the diagnostic significance of this finding has not, to our knowledge, been emphasized.

Adult↗

Total shoulder replacement.

In total shoulder replacement the result is highly dependent upon the integrity or reconstructability of the muscles, tendons, and capsule, as well as the experience of the surgeon. Stability and function of an unconstrained implant are a result of the interrelationship of critical factors such as humeral length, humeral and glenoid version, appropriate abductor tension, rotator cuff integrity, and capsular reconstruction. If these factors are not present and preserved, they must be reconstructed. The results obtained in this study are comparable to those previously published using similar shoulder arthroplasty systems. Total shoulder replacement must be considered a relatively new procedure, but results justify some optimism for the durability of this procedure.

Adult↗

Adhesive bacterial colonization of exposed traumatized tendon.

Recent studies of compromised or damaged tissues, as well as biomaterials, have shown that they provide a particularly fertile substratum for bacterial colonization. Colonization in these environments is mediated by a process of microbial adhesion to surfaces of the substrata. In this report, we present electron microscopic studies of a portion of damaged and infected tendon. These studies demonstrate colonies of bacteria surrounded by a ruthenium red-staining exopolysaccharide biofilm and adhesion to the surface of the tendon by means of an exopolysaccharide polymer. We suggest that this adhesive form of bacterial colonization may partially explain the resistance of exposed tendon to effective debridement by simple mechanical measures and to coverage with granulation tissue, partial-thickness skin grafts, and vascularized tissue grafts.

Adult↗

Bilateral rupture of the patella tendon in an otherwise healthy male patient following minor trauma.

A case of bilateral patella tendon rupture in an otherwise healthy 38-year-old man who sustained relatively minor trauma is presented. A flexion moment against a contracted or contracting quadriceps muscle is thought to have been the mechanism of injury. A survey of the literature yielded reports of three other cases of otherwise healthy patients who had had bilateral simultaneous disruption of the patella tendons.

Adult↗

Inhibition of bacterial adhesion by antibacterial surface pretreatment of vascular prostheses.

Polytetrafluoroethylene grafts were pretreated with oxacillin, with the cationic detergent benzalkonium, or with both substances, either at room temperature or at 90 degrees C. Inhibition zones ranging from 6.4 to 15.2 mm formed around all grafts incubated on Staphylococcus aureus-streaked agar plates except control disks and those treated with oxacillin. Treated grafts were exposed in vitro to S. aureus in high concentration, followed by distilled water lavage. The graft surface was then stained with ruthenium red to stain polysaccharides and studied by scanning and transmission electron microscopy. Colonization of the graft surface by adhesive bacteria was demonstrated in all cases, although it was less prevalent on grafts pretreated with benzalkonium bound at 90 degrees C.

Adhesiveness↗

Intramedullary nailing and reaming for delayed union or nonunion of the femoral shaft. A report of 105 consecutive cases.

One hundred five consecutive patients with a diagnosis of delayed union (61 patients) or nonunion (44 patients) of the femoral shaft from February 1968 to November 1983 were managed by intramedullary reaming and nailing. The procedure was accomplished by closed techniques in 82 of the cases. Adequate follow-up study was obtained in 101 patients; all but four showed clinical and radiologic union at an average of 20 weeks following the procedure, with an overall union rate of 96%. The four patients whose fractures failed to consolidate with this treatment had repeat procedures with placement of thicker nails, and all subsequently healed.

Adult↗

Nosocomial pulmonary infection: possible etiologic significance of bacterial adhesion to endotracheal tubes.

Biomaterials are essential for life support and monitoring of critically ill patients, but their use increases the risk of nosocomial infection. Of the various plastics used for life support and monitoring devices, polyvinylchloride is one to which bacteria most readily adhere. Through the use of qualitative culture techniques and scanning and transmission electron microscopy, we studied the surfaces of polyvinylchloride endotracheal tubes removed from 25 ICU patients, to determine if bacterial adhesion to those tubes was sufficient to provide a possible source for repeated contamination of the tracheobronchial tree. Of the surfaces studied, 16% were partially covered and 84% were completely covered by an amorphous bacteria-containing matrix. Some biofilm-enclosed bacterial aggregates projected from the matrix into the lumen of the tube. The mechanism by which endotracheal tubes repeatedly inoculate the lungs of intubated patients may prove to be dislodgment of such aggregates by suction apparatus.

Adult↗

Adherent bacterial colonization in the pathogenesis of osteomyelitis.

Direct scanning electron microscopy of material obtained during surgical debridement of osteomyelitic bone showed that the infecting bacteria grew in coherent microcolonies in an adherent biofilm so extensive it often obscured the infected bone surfaces. Transmission electron microscopy showed this biofilm to have a fibrous matrix, to contain some host cells, and to contain many bacteria around which matrix fibers were often concentrated. Many bacterial morphotypes were present in these biofilms, and each bacterium was surrounded by exopolysaccharide polymers, which are known to mediate formation of microcolonies and adhesion of bacteria to surfaces in natural ecosystems and in infections related biomaterials. The adherent mode of growth may reduce the susceptibility of these organisms to host clearance mechanisms and antibiotic therapy and thus may be a fundamental factor in acute and chronic osteomyelitis.

Acute Disease↗

Bacterial colonization of percutaneous sutures.

The direct electron microscopic examination of 15 sutures and 15 staples removed from 10 healed surgical wounds showed, on the intradermal portions, consistent colonization by bacteria growing in adherent biofilms. This clearly demonstrable bacterial colonization of biomaterials within the wound tract had not resulted in infection or perceptible inflammation in any of the wounds. These bacterial cells were of several morphotypes, including gram-positive cocci, and all specimens yielded cultures of the autochthonous (native) skin bacterium, Staphylococcus epidermidis. The bacteria within the wound tracts were enveloped by extracellular material that appeared on scanning electron microscopy to be a condensed amorphous residue and on transmission electron microscopy to be a fibrous extracellular matrix. We suggest that this mode of growth, in which the colonizing bacteria are enveloped in a copious exopolysaccharide glycocalix, protects the bacteria from host defense factors and accounts for their persistence on the suture surfaces until they are removed with the sutures.

Bacillus↗

Characterization of patients with high-energy lower extremity trauma.

PURPOSE: (a) to report the demographic, socioeconomic, behavioral, social, and vocational characteristics of patients enrolled in a study to examine outcomes after high-energy lower extremity trauma (HELET) and to compare them with the general population; (b) to determine whether characteristics of patients undergoing limb salvage versus amputation after HELET are significantly different from each other. DESIGN AND STUDY POPULATION: A prospective study of 601 patients admitted with high-energy lower extremity trauma to eight Level I trauma centers. PROCEDURES: Patients were evaluated during the initial hospitalization. They are being followed up for 24 months postinjury. Study patients are compared with the general population by using census information, population survey data, and published norms. Characteristics of patients undergoing limb salvage versus amputation are also compared. RESULTS: Most patients were male (77 percent), white (72 percent), and between the ages of twenty and forty-five years (71 percent). Seventy percent graduated from high school (compared with 86 percent nationally) (p < 0.05). One fourth lived in households with incomes below the federal poverty line, compared with 16 percent nationally (p < 0.05). The percentage with no health insurance (38 percent) was also higher than in the general population (20 percent) (p < .05). The percentage of heavy drinkers was over two times higher than reported nationally (p < 0.01). Study patients were slightly more neurotic and extroverted and less open to new experiences. When patient characteristics were compared for those undergoing amputation versus limb salvage, no significant differences were found among any of the variables (p > 0.05). CONCLUSION: In conclusion, LEAP patients differ in important ways from the general population. However, the decision to amputate verus reconstruct does not appear to be significantly influenced by patient characteristics.

Adolescent↗

Musculoskeletal injuries in theatrical dance students.

Three hundred and fifty-two injuries in 185 theatrical dance students at the North Carolina School of the Arts were diagnosed and treated from September 1981 through May 1982, the most recent academic year. The total number of dancers enrolled in the school was 218; thus, 84.9% of the dance students were evaluated for an injury by a physician, with 87.8% of the injuries sustained during dance. Approximately one-fourth of the dance-related injuries involved the foot or ankle. The injuries were usually not severe, and proved amenable to treatment by conservative measures.

Ankle Injuries↗