Surgical approach to the posterior fossa in children, including anesthetic considerations and complications: The prone and the sitting position. Technical note.

INTRODUCTION: Medulloblastoma (MB) in children is, in most cases, a midline lesion located in the posterior fossa, with a high tendency to invade the fourth ventricle (and sometimes its floor). METHODS: In this technical note, we present both the sitting and the prone position for children with medulloblastoma. These positions will be described together by deliberately deciding not to oppose one against the other. The park bench position, seldom used in pediatric neurosurgery is not described here. The latter procedure can be useful, however, for MB located more laterally or within the cerebellopontine angle. RESULTS: The aim of this technical note is to provide the reader with a step by step procedure (from installation to closure), at least from the author's point of view. A special focus regarding anesthetic considerations is also provided. This anesthesia requires perfect coordination and communication between both the anesthetic and surgical teams. Complications of posterior fossa surgery are mentioned as well. Some of the advantages and disadvantages of each positions are mentioned. CONCLUSION: Only careful installation, respect of certain surgical principles (careful attention of the vermis and dentate nuclei for example), knowledge of anatomy, closure and perioperative monitoring, screening and immediate correction of potentially devastating complications will enable surgeons to obtain the best results from their surgery.

The relationship between spontaneous cerebrospinal fluid leak and idiopathic intracranial hypertension.

Surgical treatment of spontaneous cerebrospinal fluid (CSF) leak is now performed by ENT surgeons, endonasal endoscopy being preferred to craniotomy as less invasive. However, it is often the symptom of underlying idiopathic intracranial hypertension, which lies outside the traditional sphere of ENT competence. Surgery is a necessary step, but should not obscure the need to treat the underlying pathology. This treatment is complex, and requires multidisciplinary team-work between otorhinolaryngologist, ophthalmologist, neurologist, neurosurgeon, radiologist, dietician, endocrinologist and psychotherapist. The present update details this multidisciplinary management to which the ENT surgeons must be attentive before and after spontaneous CSF leak repair.

Optic pathway tumor in children: Toward a new classification for neurosurgical use.

OBJECT: Optic pathway tumors (OPT) represent a challenge for pediatric neurosurgeons. Role of surgery is debated due to the high risk of iatrogenic damage, and in lasts decades it lost its importance in favor of chemotherapy. However, in some cases surgery is necessary to make biomolecular and histological diagnosis, to manage intracranial hypertension (IH) and to cooperate with medical therapies in controlling tumor relapse. With the aim to standardize selection of surgical OPT cases, we propose a simple, practical and reproducible classification. METHODS: We retrospectively analyzed data of 38 patients with OPT treated at our institution (1990-2018). After careful analysis of MRI images, we describe a new classification system. Group 1: lesion limited to one or both optic nerve(s). Group 2: chiasmatic lesions extending minimally to hypothalamus. Group 3: hypothalamo-chiasmatic exophitic lesions invading the third ventricle; they can be further divided on the base of concomitant hydrocephalus. Group 4: hypothalamo-chiasmatic lesions extending widely in lateral direction, toward the temporal or the frontal lobes. Patients' data and adopted treatment are reported and analyzed, also depending on this classification. RESULTS: Twenty children were operated on for treatment of OPT during the study period. Permanent clinical impairment was noted in 5 (25%) of operated patients, while visual improvement was noted in 1 patient. OS rate was 100% at 5 years, with a median follow up of 9 years (ranging from 2 to 23). Prevalence of intracranial hypertension and proportion of first-line surgical treatment decision were significantly higher in groups 3-4 compared to groups 1-2 (P<0.001 for both tests). CONCLUSION: Surgery can offer a valuable therapeutic complement for OPT without major risk of iatrogenic damage. Surgery is indispensable in cases presenting with IH, as in groups 3 and 4 lesions. Eligibility of patients to surgery can be based on this new classification system.