Traitement des métastases cérébrales par radiochirurgie stéréotaxique : étude de 33 cas liés à un accident de « surexposition »

The consequences of a dosimetric radiosurgery accident are not the same as a conventional radiotherapy accident. The objective of this study was to estimate the clinical and radiological outcome of patients treated by radiosurgery for metastasis during the period of the overexposure accident that occurred in the Toulouse Radiosurgery Unit. Between April 2006 and March 2007, 33 patients with 57 metastases were treated in the Toulouse Radiosurgery Unit (Novalis^®, BrainLab). An initial error in the estimation of the scatter factors led to an overexposure to radiation. The median age was 55 years [range, 35-85]. Twenty-one patients (64%) harbored a single metastasis. The primary tumor location was lung (16 cases), kidney (nine cases), breast (four cases), and others (four cases). The mean tumoral volume was 3.2 cm³ [0.04-14.07]. The mean prescribed dose at the isocenter was 20 Gy [range, 10-23], the mean delivered dose was 31.5 Gy [range, 13-52], and the mean overdose was 61.2% [range, 5.6-226.8]. In order to evaluate the consequences of the overdose, three parameters were analyzed: a risk index using dose and volume, the volume of parenchyma that received more than 12 Gy, and the mean dose in a sphere of 20 cm³ surrounding the target volume. Median actuarial survival was 14.1 months, the survival rate was 79.4 % at six months, 59.1% at 12 months, and 27.2% at 24 months. The rate of tumor control was 80.7%. No morbidity was observed. There was no correlation between death and the parameters studied. The survival rates and times observed in our study of the patients treated for brain metastases by radiosurgery and overexposed were among the good results of the international literature. Deaths were not related to the overdose and no side effect was noted. This dosimetric accident has not had worse consequences in this population.     

Chirurgie arthroscopique de l’épaule et complications ischémiques cérébrales

The authors report three cases in which cerebral ischemia occurred during arthroscopic shoulder surgery performed in beach chair position under general anaesthesia and interscalene plexus block. Several similar cases have been published in the literature. This rare but extremely severe complication is related to the decrease in cerebral perfusion pressure (CPP). Monitoring of CPP in the beach chair position using the measurement of arterial pressure and taking into account the hydrostatic gradient is essential. Prevention includes correction of preoperative hypovolaemia, treatment of postural arterial hypotension, adequate installation of the patient's head, aggressive treatment of perioperative arterial hypotension (whatever the cause) and avoidance of deliberate perioperative arterial hypotension. Routine use of non-invasive monitoring of cerebral oxygenation has been advocated to avoid this accident but its usefulness has to be confirmed by clinical studies.     

Prise en charge anesthésique de l’accouchement des patientes porteuses d’une bicuspidie aortique. À propos de deux cas consécutifs

Cardiac diseases are the second cause of non-obstetrical death during pregnancy in France. Bicuspid aortic valve is the most frequent congenital cardiac disease but its characteristics are little known. We report two consecutive cases of pregnant patients with aortic bicuspidy, one with a severe aortic stenosis and one with a severe dilatation of the ascending aorta. We describe the anaesthetic management of delivery for these two cases and summarize the current recommendations for management of this condition during pregnancy.