title: The lateral infratrigeminal transpontine window to deep pontine lesions.
abstract: OBJECTIVE
  Surgery of brainstem lesions is increasingly performed despite the fact that surgical indications and techniques continue to be debated. The deep pons, in particular, continues to be a critical area in which the specific risks related to different surgical strategies continue to be examined. With the intention of bringing new knowledge into this important arena, the authors systematically examined the results of brainstem surgeries that have been performed through the lateral infratrigeminal transpontine window.
  
  
  METHODS
  Between 1990 and 2013, 29 consecutive patients underwent surgery through this window for either biopsy sampling or for removal of a deep pontine lesion. All of this work was performed at the Department of Neurosurgery of the Istituto Nazionale Neurologico "Carlo Besta", in Milan, Italy. A retrospective analysis of the findings was conducted with the intention of bringing further clarity to this important surgical strategy.
  
  
  RESULTS
  The lateral infratrigeminal transpontine window was exposed through 4 different approaches: 1) classic retrosigmoid (15 cases), 2) minimally invasive keyhole retrosigmoid (10 cases), 3) translabyrinthine (1 case), and 4) combined petrosal (3 cases). No deaths occurred during the entire clinical study. The surgical complications that were observed included hydrocephalus (2 cases) and CSF leakage (1 case). In 6 (20.7%) of 29 patients the authors encountered new neurological deficits during the immediate postoperative period. All 6 of these patients had undergone lesion removal. In only 2 of these 6 patients were permanent sequelae observed at 3 months follow-up. These findings show that 93% of the patients studied did not report any permanent worsening of their neurological condition after this surgical intervention.
  
  
  CONCLUSIONS
  This retrospective study supports the idea that the lateral infratrigeminal transpontine window is both a low-risk and safe corridor for either biopsy sampling or for removal of deep pontine lesions.
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferroli
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Marco
authors.initials: M
authors.lastname: Schiariti
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Roberto
authors.initials: R
authors.lastname: Cordella
authors.affiliation: Neuroradiology, Fondazione IRCCS Istituto Neurologico "Carlo Besta"; and.
authors.forename: Carlo
authors.initials: C
authors.lastname: Boffano
authors.affiliation: Neuroradiology, Fondazione IRCCS Istituto Neurologico "Carlo Besta"; and.
authors.forename: Simone
authors.initials: S
authors.lastname: Nava
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Emanuele
authors.initials: E
authors.lastname: La Corte
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Claudio
authors.initials: C
authors.lastname: Cavallo
authors.affiliation: Unit of Human Pathology, Department of Health Sciences, San Paolo Hospital Medical School, University of Milano, Milan, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Bauer
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Melina
authors.initials: M
authors.lastname: Castiglione
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Morgan
authors.initials: M
authors.lastname: Broggi
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Francesco
authors.initials: F
authors.lastname: Acerbi
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Broggi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000473:pathology / Q000601:surgery*; D020295:Brain Stem Neoplasms / Q000473:pathology / Q000601:surgery*; D002648:Child; D005260:Female; D006392:Hemangioma, Cavernous / Q000473:pathology / Q000601:surgery*; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000379:methods*; D011149:Pons / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: CMAP = compound muscle action potential; CN = cranial nerve; DTI = diffusion tensor imaging; GTR = gross-total resection; MEP = motor evoked potential; SSEP = somatosensory evoked potential; STR = subtotal resection; brainstem; diagnostic and operative techniques; fiber tractography; lateral approach; mRS = modified Rankin Scale; pons; transpontine approach