Intraoperative blood loss in bimaxillary orthognathic surgery with multisegmental Le Fort I osteotomies and additional procedures.

Autologous blood donation is not currently recommended by most authors for routine bimaxillary osteotomies. There are few data about bimaxillary procedures with multisegmental maxillary osteotomies. Our aim was to investigate the effect of additional osteotomies and iliac crest grafts on operative blood loss. A total of 225 consecutive patients having bimaxillary multisegmental osteotomies during a three-year period (January 2006-January 2009) were examined to see if their haemoglobin concentration and packed cell volume were reduced. The influence of iliac crest grafts, additional osteotomies (genioplasty, malar osteotomy, iliac crest graft, anterior mandibular segmental osteotomy), operating time, age, and sex were assessed. Neither age nor sex influenced blood loss, whereas operating time correlated significantly with reductions in haemoglobin concentration and packed cell volume. Blood loss was significantly higher in the group who had additional procedures (p 0.001 for haemoglobin concentration and packed cell volume) than in the group who had no additional procedures, whereas there were no significant differences among the three subgroups who had additional procedures (additional osteotomies, iliac crest grafts, or both procedures). Four patients who had additional procedures required transfusion, whereas no blood was given in the group who had no additional procedures. Because the transfusion rate was so low, we could make no general recommendation for preoperative blood donation in such cases.

Accuracy of maxillary positioning in bimaxillary surgery.

The aim of the study was to investigate the accuracy of a modified pin system for the vertical control of maxillary repositioning in bimaxillary osteotomies. The preoperative cephalograms of 239 consecutive patients who were to have bimaxillary osteotomies were superimposed on the postoperative films. Planned and observed vertical and horizontal movements of the upper incisor were analysed statistically. The mean deviations of -0.07 mm (95% confidence intervals (CIs) -0.17 to 0.04 mm) for the vertical movement and 0.12 mm (95% CI -0.06 to 0.30 mm) for the horizontal movement did not differ significantly from zero. Comparison of the two variances between intrusion and extrusion of the maxilla did not differ significantly either (p=0.51). These results suggest that the modified pin system for vertical control combined with interocclusal splints provides accurate vertical positioning of the anterior maxilla in orthognathic surgery.

Intravenous brain-derived neurotrophic factor reduces infarct size and counterregulates Bax and Bcl-2 expression after temporary focal cerebral ischemia.

BACKGROUND AND PURPOSE: Pretreatment with intraventricular brain-derived neurotrophic factor (BDNF) reduces ischemic damage after focal cerebral ischemia. In this experiment we studied the effect of intravenous BDNF delivered after focal cerebral ischemia on neurological outcome, infarct size, and expression of proapoptotic and antiapoptotic proteins Bax and Bcl-2, respectively. METHODS: With the use of the suture occlusion technique, the right middle cerebral artery in rats was temporarily occluded for 2 hours. Thirty minutes after vessel occlusion, BDNF (300 microg/kg per hour in vehicle; n=12) or vehicle alone (n=13) was continuously infused intravenously for 3 hours. After 24 hours the animals were weighed and neurologically assessed on a 5-point scale. The animals were then killed, and brains underwent either 2,3,5-triphenyltetrazolium chloride staining for assessment of infarct volume or paraffin embedding for morphology and immunohistochemistry (Bax, Bcl-2). RESULTS: Physiological parameters (mean arterial blood pressure, PO(2), PCO(2), pH, body temperature, glucose) and weight revealed no difference between groups. Neurological deficit was improved in BDNF-treated animals versus controls (P:<0.05, unpaired, 2-tailed t test). Mean+/-SD infarct volume was 229.7+/-97.7 mm(3) in controls and 121.3+/-80.2 mm(3) in BDNF-treated animals (P:<0.05, unpaired, 2-tailed t test). Cortical infarct volume was 155.5+/-78.5 mm(3) in the placebo group and 69.9+/-50.2 mm(3) in the BDNF-treated group (P:<0.05, unpaired, 2-tailed t test). Subcortical infarct volume was 74.1+/-30.6 mm(3) in the placebo group and 51.1+/-26.8 mm(3) in the BDNF-treated group (P:=NS). Bax-positive neurons were significantly reduced in the ischemic penumbra in BDNF-treated animals (P:<0.05, unpaired, 2-tailed t test), whereas Bcl-2-positive neurons were significantly increased in this area (P:<0.001, unpaired, 2-tailed t test). CONCLUSIONS: This study demonstrates a neuroprotective effect of BDNF when delivered intravenously after onset of focal cerebral ischemia. As shown here, one possible mechanism of action of neuroprotection of BDNF after focal ischemia appears to be counterregulation of Bax/Bcl-2 proteins within the ischemic penumbra.