Management of an extended clivus fracture: a case report.

BACKGROUND: Clivus fractures are highly uncommon. The classification by Corradino et al. divides the different lesions in longitudinal, transverse and oblique fractures. Longitudinal types are associated with the highest mortality rate between 67 - 80%. Clivus fractures are often found after high velocity trauma, especially traffic accidents and falls. The risk of neurologic lesions is high, because of the anatomic proximity to neurovascular structures like the brainstem, the vertebrobasilar artery, and the cranial nerves. Longitudinal clivus fractures have a special risk of causing entrapment of the basilar artery and thus ischemia of the brainstem. CASE PRESENTATION: This lesion in our patient was a combination-fracture of the craniocervical junction with a transverse clivus fracture. In this case, the primary closed reduction of the clivus fracture and the immobilization with a halo device was the therapy of choice and led to consolidation of the fracture. CONCLUSION: Therapy advices and examples in the literature are scarce. We present a patient with a clivus fracture, who could be well treated by a halo device. Through detailed research of the literature a therapy algorithm has been developed.

Coronary artery bypass and superior vena cava syndrome.

Superior vena cava syndrome is the obstruction of the superior vena cava or its main tributaries by benign or malignant lesions. The syndrome causes edema and engorgement of the vessels on the face, neck, and arms, nonproductive cough, and dyspnea. We discuss the case of a 48-year-old obese diabetic woman who was admitted with unstable angina. She had previously been diagnosed with superior vena cava syndrome. Urgent coronary artery bypass grafting was necessary Although thousands of coronary artery bypasses are performed every year, there are not many reports on patients with superior vena cava syndrome who successfully undergo cardiopulmonary bypass and coronary artery grafting with an internal mammary artery as the conduit. The results of the case and alternative recommended methods are discussed.

Dopexamine maintains mesenteric blood flow during systemic hypoxemia in the neonatal piglet.

In adults, dopexamine is a specific dopaminergic and Beta2-adrenergic agonist; its effects in neonates are unknown. Ultrasonic flow probes were placed around the ascending and descending aorta and cranial mesenteric artery of 0- to 2-day-old and 2-week-old piglets. Animals of each age group (9 to 14 per group) were subjected to (1) dopexamine infusion (5 microg/kg/min); (2) 30 minutes of hypoxia (inspired oxygen content 0.12) followed by 30 minutes of reoxygenation; and (3) dopexamine infusion during hypoxia and reoxygenation. In both age groups dopexamine alone increased ascending aorta blood flow (cardiac output minus coronary artery blood flow), mildly decreased mean arterial pressure, and increased cranial mesenteric artery blood flow. Compared to baseline values, 30 minutes of hypoxia produced significant (P <0.05, analysis of variance) decreases in cranial mesenteric artery blood flow in 0- to 2-day-old (58 +/- 13 ml/min vs. 30 +/- 8 ml/min) and 2-week-old (125 +/- 18 ml/min vs. 60 +/- 11 ml/min) piglets. In all cases blood flow returned to baseline values after reoxygenation. In both animal groups treated with dopexamine before hypoxia, the decreases in cranial mesenteric artery blood flow were eliminated (47 +/- 5 ml/min vs. 44 +/- 6 ml/min in 0- to 2-day-old piglets; 140 +/- 27 ml/min vs. 117 +/- 18 ml/min in 2-week-old piglets). Dopexamine may prove to be of clinical benefit when neonates are threatened by hypoxemia-induced decreases in intestinal blood flow.

Mild preischemia hypothermia adversely affects postischemic myocardial function in the neonatal piglet heart.

BACKGROUND: During cardiac surgery, operative hypothermia has been shown to be beneficial in certain situations, although in children perioperative hypothermia has been associated with several physiologic alterations that have proven detrimental to their postoperative function. Little attention has been given to the effects of mild (34.5 degrees C) perioperative hypothermia on postischemic myocardial function in the pediatric population. It was hypothesized that mild hypothermia would be detrimental to postischemic ventricular function in the neonatal heart. METHODS: Neonatal (0-2 days old) piglets were subjected to mild perioperative hypothermia without rewarming (HT-only, n = 6), hypothermia followed by rewarming (HT-RW, n = 6), or continuous normothermia (NT, n = 8). The hearts were rapidly excised, suspended on an isolated perfusion apparatus, and allowed to spontaneously beat while being perfused with an asanguinous solution. All hearts were subjected to 20 min global, normothermic, zero-flow ischemia followed by 45 min oxygenated crystallite buffer reperfusion (I-R). RESULTS: Compared to that of NT piglets, there were significant (P < 0.05) reductions in recovery of left ventricular (LV) diastolic and systolic function following ischemia and reperfusion in HT-RW animals. When the hearts were rendered ischemic without first rewarming, the degree of myocardial dysfunction was not as severe. In contrast to the NT piglets, HT-RW animals demonstrated significant (P < 0.05) reductions in the final recovery of LV developed pressure (71 +/- 6 vs 105 +/- 6 in NT), LV rate pressure product (52 +/- 4 vs 102 +/- 9 NT), and LV end diastolic pressure (32 +/- 7 vs 3 +/- 1 in NT) following I-R. When compared to the HT-RW group, HT-only piglets did not exhibit significant differences in systolic function, although diastolic function was minimally altered initially as evidenced by the slight elevation of LV end diastolic pressure at 5 min, with reperfusion in the HT-only group (P < 0.05). CONCLUSIONS: In this newborn piglet model, mild hypothermia significantly reduces recovery of systolic and diastolic left ventricular function when followed by an episode of global myocardial ischemia-reperfusion only when the animals are returned to normothermia prior to the ischemic insult. When hypothermia is immediately followed by the ischemic event, left ventricular function is unaffected.

Clinical pharmacokinetics of methoxsalen and other psoralens.

The psoralen derivative methoxsalen and to a lesser extent some other furocoumarin congeners, including bergapten and trioxsalen, have acquired a place in the treatment of psoriasis and other dermatoses. They are inactive after oral or topical administration unless combined with irradiation with long-wave ultraviolet light (UVA). This combination is referred to as photochemotherapy or PUVA (psoralen plus UVA). Usually a standard dose of methoxsalen (0.5 to 0.7 mg/kg) is given 2 hours prior to irradiation, and the light dose is assessed individually. Differences in response are often due to the unpredictable pharmacokinetic behaviour of the drug. Reversed-phase high-performance liquid chromatography is the method of choice for determining methoxsalen concentrations in body fluids, but gas chromatography with electron capture detection and thin-layer chromatography with fluorescence densitometry also give favourable results. The absorption of methoxsalen, and hence clinical response, is affected by concomitant food ingestion and by differences in drug formulation. A liquid preparation in soft gelatin capsules or a microenema give higher and more rapidly appearing maximum serum concentrations (Cmax) than crystalline methoxsalen in tablets or capsules. With a standard dose of tablets, Cmax is in the range of 50 to 250 micrograms/L and appears between 1 and 2 hours after ingestion. The drug has a high, but variable, intrinsic metabolic clearance and is almost completely metabolised. Serum elimination half-life is in the order of 0.5 to 2 hours. There is a large interpatient variability in the clearance of methoxsalen (40 to 650 L/h); the relative distribution volume ranges between 1 and 9 L/kg. Concentrations in suction blister fluid (sbf) are approximately one-third of Cmax in serum and remain relatively constant as long as the plasma concentration exceeds the suction blister fluid level. Individuals with a high methoxsalen clearance and low Cmax usually show less biological sensitivity to PUVA (in terms of minimal phototoxic dose of UVA) than low-clearance patients and frequently a less favourable clinical response. Hence Cmax can be used for the purpose of therapeutic drug monitoring and, in practice, this may be determined by measuring serum concentrations at least at 1, 2, and 3 hours after ingestion. Bergapten is somewhat less active than methoxsalen but has similar pharmacokinetic characteristics. The bioavailability of trioxsalen is poor after oral intake and this drug is mainly administered topically.