Citations

Background Laboratory studies suggest that nitrous oxide augments brain injury after ischemia or hypoxia. The authors examined the relation between nitrous oxide use and outcomes using data from the Intraoperative Hypothermia for Aneurysm Surgery Trial. Methods The Intraoperative Hypothermia for Aneurysm Surgery Trial was a prospective randomized study of the impact of intraoperative hypothermia (temperature = 33 degrees C) versus normothermia (temperature = 36.5 degrees C) in patients with aneurysmal subarachnoid hemorrhage undergoing surgical clipping. Anesthesia was dictated by a limited-options protocol with the use of nitrous oxide determined by individual anesthesiologists. All patients were assessed daily for 14 days after surgery or until hospital discharge. Neurologic and neuropsychological testing were conducted at 3 months after surgery. Outcome data were analyzed via both univariate tests and multivariate logistic regression analysis correcting for factors thought to influence outcome. An odds ratio (OR) greater than 1.0 denotes a worse outcome in patients receiving nitrous oxide. Results Outcome data were available for 1,000 patients, of which 373 received nitrous oxide. There was no difference between groups in the development of delayed ischemic neurologic deficit. At 3 months after surgery, there were no significant differences between groups in any outcome variable: Glasgow Outcome Score (OR, 0.84; 95% confidence interval [CI], 0.63-1.14; P = 0.268), National Institutes of Health Stroke Scale (OR, 1.29; 95% CI, 0.96-1.73; P = 0.087), Rankin Disability Score (OR, 0.84; 95% CI, 0.61-1.15; P = 0.284), Barthel Activities of Daily Living Index (OR, 1.01; 95% CI, 0.68-1.51; P = 0.961), or neuropsychological testing (OR, 1.26; 95% CI, 0.85-1.87; P = 0.252). Conclusions In a population of patients at risk for ischemic brain injury, nitrous oxide use had no overall beneficial or detrimental impact on neurologic or neuropsychological outcomes.

ABSTRACT We recently described a sonication technique for the diagnosis of prosthetic knee and hip infections. We compared periprosthetic tissue culture to implant sonication followed by sonicate fluid culture for the diagnosis of prosthetic shoulder infection. One hundred thirty-six patients undergoing arthroplasty revision or resection were studied; 33 had definite prosthetic shoulder infections and 2 had probable prosthetic shoulder infections. Sonicate fluid culture was more sensitive than periprosthetic tissue culture for the detection of definite prosthetic shoulder infection (66.7 and 54.5%, respectively; P = 0.046). The specificities were similar (98.0% and 95.1%, respectively; P = 0.26). Propionibacterium acnes was the commonest species detected among culture-positive definite prosthetic shoulder infection cases by periprosthetic tissue culture (38.9%) and sonicate fluid culture (40.9%). All subjects from whom P. acnes was isolated from sonicate fluid were male. We conclude that sonicate fluid culture is useful for the diagnosis of prosthetic shoulder infection.

ABSTRACT Capsular contracture is the most common and frustrating complication in women who have undergone breast implantation. Its cause and, accordingly, treatment and prevention remain to be elucidated fully. The aim of this prospective observational pilot study was to test the hypothesis that the presence of bacteria on breast implants is associated with capsular contracture. We prospectively studied consecutive patients who underwent breast implant removal for reasons other than overt infection at the Mayo Clinic from February through September 2008. Removed breast implants were processed using a vortexing/sonication procedure and then subjected to semiquantitative culture. Twenty-seven of the 45 implants collected were removed due to significant capsular contracture, among which 9 (33%) had ≥20 CFU bacteria/10 ml sonicate fluid; 18 were removed for reasons other than significant capsular contracture, among which 1 (5%) had ≥20 CFU/10 ml sonicate fluid ( P = 0.034). Propionibacterium species, coagulase-negative staphylococci, and Corynebacterium species were the microorganisms isolated. The results of this study demonstrate that there is a significant association between capsular contracture and the presence of bacteria on the implant. The role of these bacteria in the pathogenesis of capsular contracture deserves further study.

Background There have been few biomechanical studies to clarify which size of a glenoid defect is critical. However, those studies have assumed that the defect occurred anteroinferiorly. Recent studies have reported that the defect is located anteriorly rather than anteroinferiorly. Therefore, the effect of the anterior, not anteroinferior, glenoid defect on shoulder stability needs to be investigated. Hypothesis The anterior glenoid defect would have a similar effect on anterior shoulder stability as that of the anteroinferior glenoid defect. Study Design Controlled laboratory study. Methods Eight fresh-frozen cadaveric shoulders were used (mean age, 74 years). The specimen was attached to a shoulder-testing device with the arm in abduction and external rotation. An osseous defect was created stepwise with a 2-mm increment of the defect width. The stability ratio was used to evaluate joint stability. With a 50-N axial force, the translational force applied to the humeral head was measured by a force transducer. Results The stability ratio without a defect (32% ± 6%) significantly decreased after creating a 6-mm defect (17% ± 5%; P = .0001), which was equivalent to 20% of the glenoid length. Conclusion An osseous defect at 3 o'clock with a width that was equal to or greater than 20% of the glenoid length significantly decreased anterior stability. Clinical Relevance The results suggest that reconstruction of the glenoid concavity might be necessary in shoulders with an anterior glenoid defect of at least 20% of the glenoid length.

ASTM F23.40.04, Draft Test Method for the Resistance of Materials Used in Protective Clothing to Penetration by Synthetic Blood Using a Mechanical Pressure Technique, was evaluated and compared to three other barrier test methods that apply hydrostatic pressure to the liquid and fabric. The new instrument applies continuous mechanical pressure to the fabric and synthetic blood until penetration is visible, and the penetration pressure level is recorded. The barrier properties of 14 different surgical gown materials and control fabrics were measured using the new method and ASTM F 1670 and F 1671 and AATCC 127. Surgical gown materials reinforced with films, coatings, or membranes passed ASTM F 1670 and F 1671 and reached the highest pressure level attainable on the AATCC 127 and ASTM F23.40.04 tests. Single-layer and fabric reinforced gowns exhibited varying degrees of liquid resistance. The new method simulates the high mechanical pressures of short duration that occur during surgery. It deserves consideration as a standard.

Objective:To provide recommendations on the use of disease-modifying agents in the management of multiple sclerosis (MS) and to ensure that treatment will be available to those patients who may benefit.Methods:An initial draft of the consensus statement was prepared by the Steering Committee and amended in the light of written comments from a group of MS specialists. At a subsequent workshop, the wording of the consensus statement was discussed, modified if necessary, and the participants indicated their level of support using an electronic voting system. A new draft of the statement was then sent to a much larger group of international opinion leaders in MS for further comment.Results:A number of statements were agreed, which outline the criteria for consideration of disease-modifying therapy for MS and recommendations for treatment. Each statement was accepted completely, or with only minor reservations by 95% or more of those present at the workshop. Conclusions: Periodic reviews and modifications to the statement will be required, as new approaches to the treatment of MS and other therapeutic agents become available. Multiple Sclerosis (2002)8,19-23