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The e-mémoires of the Académie Nationale de Chirurgie

Retrosigmoïd Approach Serving Ponto Cerebellar Angle Pathologies: Microscope and Endoscope are Both Useful for a Minimal Invasive Procedure

BAZIN A | CHAYS A

Seance of wednesday 20 november 2019 (L'endoscopie au service de la chirurgie dans l'angle ponto-cérébelleux)

DOI number : 10.26299/zk5k-ww85/emem.2018.2.017

Abstract

Ponto Cerebellar Angle (PCA) pathologies are numerous, vestibular schwannomas (or acoustic neuromas) remaining the most frequent; but there are many other indications to reach this surgical area such as vestibular neurotomy in incapacitating Meniere's disease or vascular compressions as trigeminal neuralgia, facial spasm, etc…
In order to reach the PCA, surgeons may use three main approaches: the retrosigmoïd (RS) approach -originally the sub-occipital neurosurgical access-, the trans-labyrinthin (TL) approach described and used by the otologists ENT, and the sub-temporal approach. The RS approach is the only one which allows the treatment of all theses pathologies, owing to his very wide opening.
We describe the minimal invasive RS approach step by step as we have been practicing it in Reims for 15 years, with a mixed team of one neurosurgeon and one ENT surgeon; the entire procedure is performed with the two practitioners present, from the patient's positioning until the end of the procedure. Reduction of the bone opening is facilitated by endoscopy, and it gives also a perfect view of vascular conflicts; it is therefore a useful complement of microscopic view.
In our practice, it is a safe technic, quickly performed (less than an hour) which leads to all PCA structures: vessels –vertebral artery, the three cerebellar arteries- and the nerves from the IVth to the XIIth. Unlike the trans-labyrinthin approach, RS respects the vestibular and acoustic structures of inner ear; this is very important in small neuromas and all other functional indications.
During the last 15 years, we have performed surgery on more than 800 patients wi