Transmastoid presigmoid retrolabyrinthine approach for removal of pontine cavernous malformation: how I do it.

BACKGROUND: Bleeding of brainstem cavernous malformations (BSCM) cause high morbidity and should be treated surgically whenever possible. METHOD: We present a 56-year-old man, who was diagnosed with a BSCM at right pons, which caused functional impairments of dorsal column, spinothalamic tract, cochlear nucleus, and middle cerebellar peduncle. A transmastoid presigmoid retorlabyrinthine approach via the lateral pontine zone (LPZ), with an assistance of imaging guidance and intraoperative neurophysiological monitoring, was performed to completely resect the BSCM. The patient recovered despite a transient worsening of cerebellar sign and hemiparesthesia for 1 week, without surgical complications. CONCLUSIONS: A transmastoid presigmoid retrolabyrinthine approach through LPZ is safe and effective for lateral pontine BSCM resection.

Individual cerebrocerebellar functional network analysis decoding symptomatologic dynamics of postoperative cerebellar mutism syndrome.

Introduction: Postoperative cerebellar mutism syndrome (pCMS) consists of three types of symptoms (motoric, linguistic, and neurobehavioral) in patients with posterior fossa pathologies. The evolutional mechanism of this high cognitive syndromic complex from cerebellar origin remains unconfirmed. Previous studies analyzing CMS patients mostly focused on the association between structural abnormalities that occur during CMS, of which proximal efferent cerebellar pathway (pECP) injury appears to be the most common pathogenesis. However, structural imaging may not be sensitive enough to determine the dynamic course of CMS, since the symptomatology is primarily an output of cerebral operation. Method: We took a network approach in a child during her course of development and recovery of the pCMS. On the other hand, a network neuroscience approach using a mathematical model to extract information from functional imaging to generate interregional connectivity provides abundant evidence that the cerebellum is influential in modulating cerebral functions. Result: This study applied a network approach to children with pCMS. An individual cerebrocerebellar functional network analysis using graph theory was then performed to determine the network dynamics during CMS. Cross-validation of clinical neurophysiology and functional neuroscience suggested the critical role of the pECP within CMS from the network analysis. Conclusion: The employed approach was therefore useful in determining the complex clinical symptoms using individual functional network analysis, which bridges the gap between structural neuroimaging and clinical neurophysiology.