Plain radiograph assessment of spinal hardware.

The frequency and variety of spinal instrumentation has increased tremendously over the past 100 years, and imaging plays an important role in evaluating the postoperative spine. Although assessment of spinal hardware often involves a multimodality approach, plain radiographs are the most commonly used modality, given accessibility, cost, relatively low radiation dose compared with computed tomography, and provision of positional information. An approach to assessment of plain radiographs of the postoperative spine is discussed, and examples of common postoperative complications are provided, including infection, hardware failure, incomplete fusion, and junctional failure.

Ultrasound-guided interventional radiology in critical care.

Ultrasound-guided intervention is becoming an increasingly popular and valuable tool in the critical care setting. In general, image-guided procedures can expedite wait times and increase the accuracy, safety, and efficacy of many procedures commonly performed within intensive care units. In the intensive care unit setting, ultrasound has particular advantages over other imaging modalities such as computed tomography and fluoroscopy, including real-time visualization, portability permitting bedside procedures, and reduced exposure to nephrotoxic contrast agents. We review the technical and procedural aspects of a number of ultrasound-guided interventions appropriate for critical care patients. These include central venous catheter deployment, thoracentesis, paracentesis, and drainage of a wide variety of abscesses, and percutaneous nephrostomy, percutaneous cholecystectomy, and inferior vena cava filter placement. Although we believe ultrasound is significantly underutilized in critical care today, we anticipate that with the improvement of ultrasound technology and the innovation of new ultrasound-guided procedures, the role of ultrasound in the intensive care unit will continue to expand, with bedside ultrasound-guided interventions increasingly becoming the norm.

Biofilm formation and acyl homoserine lactone production in the Burkholderia cepacia complex.

Acyl homoserine lactone (acyl-HSL)-mediated gene regulation has been shown to influence biofilm formation in one Burkholderia cepacia cystic fibrosis isolate, but it is not known whether this relationship is a consistent feature of the several genomic species that make up the B. cepacia complex (BCC). We screened strains belonging to genomovars I to V of the BCC for biofilm formation on an abiotic surface and for acyl-HSL synthesis. We determined that organisms from each of these genomovars were capable of biofilm formation. Similarly, acyl-HSL was synthesized by organisms from each of genomovars I to V, with most isolates producing octanoyl-HSL in greatest abundance. When biofilms were grown in Luria broth, acyl-HSL synthesis and biofilm formation appeared to be associated, but these phenotypes were independent when the biofilms were grown in basal salts containing citrate. Genomovar V strains synthesized the greatest quantities of acyl-HSL, and genomovar II and III-A strains elaborated the most abundant biofilms. Quorum sensing may play a role in BCC pathogenesis, but it may not regulate biofilm formation under all growth conditions.