Abdominal aortic injury during vertebroplasty.

STUDY DESIGN: Case report. OBJECTIVE: To describe an intraoperative complication occurring from abdominal aortic penetration during a vertebroplasty procedure for vertebral fractures on Th12 and L1. SUMMARY OF BACKGROUND DATA: A vertebroplasty is a minimally invasive and widely performed procedure in elderly and high-risk patients, although there is a risk of life-threatening complications including aortic injury. However, little is known about the treatment of iatrogenic aortic penetration occurring during a vertebroplasty. METHODS: An 80-year-old female underwent a scheduled vertebroplasty procedure. When the needle was advanced into the L1 vertebral body, arterial blood spurted out from the needle hub and fluoroscopic imaging revealed penetration of the aorta. To minimize bleeding, we depressed blood pressure and kept the needle in place. While vital signs were maintained, we prepared for blood transfusion and circulation monitoring and consulted a cardiothoracic surgeon and a cardiologist. Contrast medium injected via the needle revealed that a hematoma had formed to shift the aortic wall beyond the needle. Circulation was stable while pressure of the needle decreased, thus the hematoma was thought to have become coagulated and the needle was cautiously withdrawn. RESULTS: After placing the patient in a supine position, aortic angiography revealed no leakage around the aorta and she was transferred to the intensive care unit. On postoperative day 1, no leakage around the aorta was confirmed on computed tomographic scans and the patient was extubated. During the 2-year follow-up period, no arterial complication was observed. CONCLUSION: Conservative treatment is optional for accidental aortic penetration during a vertebroplasty when a tamponade effect is expected. In cases with circulatory collapse, when the tamponade effect seems insufficient or a free wall rupture is suspected, prompt removal of the needle and surgical repair should be considered. LEVEL OF EVIDENCE: 5.

Adsorption of water dimer on platinum(111): identification of the -OH···Pt hydrogen bond.

The fundamental structure of an isolated water dimer on Pt(111) was determined by means of a spectroscopic method using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Two water molecules on adjacent atop sites form a dimer through a hydrogen bond, and they rotate even at a substrate temperature of 5 K. Action spectroscopy using STM (STM-AS) for water dimer hopping allows us to obtain the vibrational spectrum of a single water dimer on Pt(111). Comparisons between the experiments and theory show that one of the OH groups of the acceptor water molecule points toward the surface to form an -OH···Pt hydrogen bond.

Different antithrombotic properties of factor Xa inhibitor and thrombin inhibitor in rat thrombosis models.

We compared the antithrombotic properties of a factor Xa inhibitor (DX-9065a) with those of a thrombin inhibitor (melagatran) in a rat disseminated intravascular coagulation model and a rat venous thrombosis model. Rat disseminated intravascular coagulation and venous thrombosis models were produced by injection of tissue factor and platinum wire placement, respectively. DX-9065a exerted antithrombotic effects dose dependently in both models. Melagatran was also effective in the venous thrombosis model, whereas it showed an aggravation in the disseminated intravascular coagulation model at low but not high doses. In the in vitro study, DX-9065a decreased the C(max) of the thrombin generation curve in plasma irrespective of whether protein C was present or not. However, melagatran increased the C(max) at low concentrations when protein C was present. This increase was not detected in protein C-deficient plasma. These results suggest that, unlike DX-9065a, melagatran in low doses aggravates disseminated intravascular coagulation by increasing thrombin generation, which may be partly due to suppression of negative feedback by activated protein C.