OBJECTIVE: The most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT.
METHODS: CT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann\'s area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored.
RESULTS: The posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications.
CONCLUSIONS: Preoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann\'s triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.

OBJECTIVE: Benign paroxysmal positional vertigo is the most common peripheral vertigo disease. The aim of this paper is to review the results obtained with the different specific particle repositioning manoeuvres, evaluating the possible risk factors linked to a poorer prognosis.
METHODS: One hundred and seventy-six patients with a diagnosis of benign paroxysmal positional vertigo were reviewed retrospectively, of whom 150 had vertigo of the posterior canal, 20 had vertigo of the horizontal canal, 3 had vertigo of the superior canal, and 3 had a double vertigo. The Epley manoeuvre was used to treat the posterior and superior canals, and Lempert manoeuvre was used to treat the horizontal canal. An imaging study by nuclear magnetic resonance with gadolin was always used in refractory cases.
RESULTS: The Epley manoeuvre showed an efficacy of 74.6 and 100% at first attempt for posterior and superior canals respectively. The efficacy of the Lempert manoeuvre for the horizontal canal was 72.72% in the patients with canalolithiasis, and 58.33% in the patients with cupulolithiasis. The treatment of patients with more than one affected canal and a history of surgery in the previous month was more difficult.
CONCLUSIONS: Particle repositioning manoeuvres show a very high success rate, allowing better results in the treatment of the posterior canal. We need more studies to confirm the suspicion that surgery may be a factor of poorer prognosis.

The benign paroxysmal positional vertigo is the most common disease in the group of peripheral vertigo. It\'s characterized by vertiginous sensation triggered by the positional changes of the head and usually lasts less than one minute. It is most frequently seen in middle-aged patients (40-50 years old) and in up 50% of cases we do not know the cause, so we refer to them as idiopathic benign paroxysmal positional vertigo. Because of the high incidence of benign paroxysmal positional vertigo in general population, it is of utmost importance to be aware of the differential diagnosis and to be able to treat this pathology with efficacy, because in most cases we can achieve excellent results performing specific and simple maneuvers.