Three-Dimensional Evaluation of Implant Positioning in the Maxillary Sinus Septum: A Retrospective Study.

BACKGROUND: The aim of this study was to simulate implant placement in the maxillary sinus septum, as a potential alternative site to avoid sinus grafting. MATERIAL AND METHODS: One hundred partially or completely edentulous patients, with their maxillary sinus septum present in the edentulous region, were selected from the database of the Department of Maxillofacial Surgery, Cliniques Universitaires Saint Luc, Bruxelles, Belgium. Three-dimensional (3D) reconstructions were created using 3D planning software. 3D reconstructions were performed for each maxillary sinus. Using the software implant library, the implants that presented the best fit with the maxillary sinus septum and that followed the established inclusion criteria were selected. RESULTS: All of the implants were inserted in premolar and molar regions. Most implants were inserted in the position of the second molar (21 of 55) or in the position of the first molar (17 of 55). In all sites the most frequently used implant was 4 mm in diameter and 7 mm in height. The mean coronal angle for the implant was 80.19±17.13 degrees and the mean sagittal angle was 94.83±9.94 degrees. The septal height represents 38.13% of the total available bone height (ABH). The mean percentage of the septum used to insert the implants was 47.33±2.47%. The septum increased the available bone height by a mean value of 2.18±1.47 mm. In 45 cases, the septa did not permit implant placement. CONCLUSIONS: In completely edentulous patients, inserting implants in sinus septa does not exclude the need for sinus grafting, but in partially edentulous patients, this minimally invasive technique is an alternative to subantral augmentation.

[Hypothermia and cerebral protection after head trauma. Influence of blood gases modifications]. / Hypothermie et protection cérébrale après traumatisme crânien. Influence des gaz du sang.

The usefulness of therapeutic hypothermia is highly debated after traumatic brain injury. A neuroprotective effect has been demonstrated only in experimental studies: decrease in cerebral metabolism, restoration of ATP level, better control of cerebral edema and cellular effects. Despite negative multicenter clinical studies, therapeutic hypothermia is still used to a better control of intracranial pressure. However, important issues need to be clarified, particularly the level and duration of hypothermia, the depth and modalities of sedation. A clear understanding of blood gases variations induced by hypothermia is needed to understand the cerebral perfusion and oxygenation changes. It is essential to recognize and to use hypothermia-induced physiological hypocapnia and alkalosis under strict control of cerebral oxygen balance (jugular venous saturation or tissue PO(2)) and also to take into account the increased affinity of hemoglobin for oxygen. Management of post-traumatic intracranial hypertension using hypothermia, directed by intracranial pressure level, and consequently for long duration, is potentially beneficial but needs further clarification.

[Falsely elevated-bispectral index]. / Un indice bispectral étrangement élevé

We report a case of a falsely elevated-bispectral index (BIS) during a general anaesthesia combining remifentanil TCI, desflurane and nitrous oxide for an isolated-limb chemotherapy. During surgery, BIS increased and stabilized around 70, with neither residual neuromuscular blockade nor clinical sign of awareness. These high BIS values were attributed to high-electromyographic activity and electric artefacts, such as extracorporeal-circulation machine and tourniquet. At the end of the surgery, the BIS returned to expected values around 50. The patient did not complain of intraoperative recall. This case reminds us that the BIS has some limits as being sensitive to EMG or environment artefacts that should be eliminated before deepening anesthesia. To do so, a decision algorithm is proposed that may be used for all situations of surprising high BIS, taking into account the level of neuromuscular blockade, clinical response to orders and the presence of devices likely to induce electrical or mechanical artefacts.