Improved accuracy of K-wire positioning into the glenoid vault by intraoperative 3D image intensifier-based navigation for the glenoid component in shoulder arthroplasty.

INTRODUCTION: This article aimed to show that navigation, based on an intraoperative mobile 3D image intensifier, can improve the accuracy of central K-wire placement into the glenoid vault for glenoid component. HYPOTHESIS: The navigated k-wire placement is more accurate and shows a smaller deviation angle to the standard centerline compared to the classical "free hand technic". METHODS: In 34 fresh frozen sheep scapulae, 17 K-wire placements using the navigation (group 1) were compared with 17 using standard "face plane technique" (group 2). The relation to glenoid standard and alternative centerlines (CL) and the position within the glenoid vault were analyzed. RESULTS: In groups 1 and 2 the angle between the K-wire and standard CL was 2.2° and 4.7°, respectively (P=0.01). The angle between the K-wire and alternative CL was 14.4° for group 1 and 17.2° for group 2 (P=0.02). More navigated K-wire positions were identified within a 5mm corridor along the glenoid vault CL (52 vs. 39; P=0.004). DISCUSSION: Intraoperative 3D image intensifier-based navigation was more accurate and precise than standard K-wire placement. TYPE OF STUDY AND LEVEL OF PROOF: Basic science study, evidence level III.

New approaches for isolation of previously uncultivated oral bacteria.

A significant number of microorganisms from the human oral cavity remain uncultivated. This is a major impediment to the study of human health since some of the uncultivated species may be involved in a variety of systemic diseases. We used a range of innovations previously developed to cultivate microorganisms from the human oral cavity, focusing on anaerobic species. These innovations include (i) in vivo cultivation to specifically enrich for species actively growing in the oral cavity (the "minitrap" method), (ii) single-cell long-term cultivation to minimize the effect of fast-growing microorganisms, and (iii) modifications of conventional enrichment techniques, using media that did not contain sugar, including glucose. To enable cultivation of obligate anaerobes, we maintained strict anaerobic conditions in most of our cultivation experiments. We report that, on a per cell basis, the most successful recovery was achieved using minitrap enrichment (11%), followed by single-cell cultivation (3%) and conventional plating (1%). Taxonomically, the richest collection was obtained using the single-cell cultivation method, followed by minitrap and conventional enrichment, comprising representatives of 13, 9, and 4 genera, respectively. Interestingly, no single species was isolated by all three methods, indicating method complementarity. An important result is the isolation and maintenance in pure culture of 10 strains previously only known by their molecular signatures, as well as representatives of what are likely to be three new microbial genera. We conclude that the ensemble of new methods we introduced will likely help close the gap between cultivated and uncultivated species from the human oral cavity.

The hemodynamic effects of sotalol and quinidine: analysis by use of rest and exercise gated radionuclide angiography.

This placebo-controlled, double-blind trial compared the hemodynamic effects of sotalol and quinidine with the use of rest and exercise gated radionuclide angiography. Patients had frequent ventricular premature depolarizations (greater than or equal to 30 VPDs/hour) and depressed cardiac function (mean ejection fraction 43 +/- 15%). Resting left ventricular ejection fraction and stroke volume index increased (p less than .002, p less than .001, respectively) during sotalol therapy, associated with a concomitant fall in heart rate (p less than .001). Quinidine also increased mean left ventricular ejection fraction, but less so than did sotalol (p less than .05). Quinidine significantly decreased left ventricular end-diastolic (p less than .05) and end-systolic (p less than .002) volumes, but had no effect on stroke volume index or heart rate. Neither drug affected cardiac index. Quinidine resulted in no symptomatic deterioration in left ventricular function or serious arrhythmia aggravation. In contrast, five patients on sotalol developed either decompensated congestive heart failure (two patients), arrhythmia aggravation (two patients), or hypotension associated with bradyarrhythmia (one patient). These patients had a unique hemodynamic profile that can be used to identify patients likely to have a poor outcome on sotalol. This profile reflected a lack of cardiac reserve, characterized by an inability to increase stroke volume and cardiac output with supine bicycle exercise.