Medial-tonsillar telovelar approach for resection of a superior medullary velum cerebral cavernous malformation: anatomical and tractography study of the surgical approach and functional implications

Acta Neurochir (Wien). 2021 Mar;163(3):625-633. doi: 10.1007/s00701-020-04418-2. Epub 2020 Jun 10.

Abstract

Background: Superior medullary velum cerebral cavernous malformations pose a challenge in terms of appropriate microsurgical approach. Safe access to this deep location as well as preservation of surrounding anatomical structures, in particular the superior cerebellar peduncle just lateral to the superior medullary velum and the dentate nuclei, is paramount to achieve a good functional outcome.

Methods: Cadaveric dissections provide useful knowledge of the normal anatomy while tractography allows a better understanding of the individual anatomy in the presence of a lesion. The medial-tonsillar telovelar approach provides a feasible corridor for accessing superior velum cerebral cavernous malformations without compromising the fibres contained in the superior cerebellar peduncle. The major cerebellar efferents-cerebello-rubral, cerebello-thalamic and cerebello-vestibular tracts-and afferents, anterior spinocerebellar, tectocerebellar and trigeminocerebellar tracts, within the superior cerebellar peduncle are preserved, and the dentate nuclei are not affected.

Results and conclusion: A retraction-free exposure through this natural posterior fossa corridor allows the patient with the anatomical and functional subtract to make a good functional recovery by minimizing the risk of a superior cerebellar syndrome, ataxia, tremor and dysmetria; decomposition of movement in the ipsilateral extremities, nystagmus and hypotonia; or akinetic mutism, reduced or absent speech with onset within the first post-operative week.

Keywords: Cerebral cavernous malformation; Superior cerebellar peduncle; Superior medullary velum; Tractography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cadaver
  • Cerebellar Diseases / prevention & control
  • Cerebellum / anatomy & histology
  • Cerebellum / diagnostic imaging
  • Cerebellum / surgery
  • Diffusion Tensor Imaging / methods*
  • Fourth Ventricle / anatomy & histology
  • Fourth Ventricle / diagnostic imaging
  • Fourth Ventricle / surgery
  • Hemangioma, Cavernous, Central Nervous System / surgery*
  • Humans
  • Natural Orifice Endoscopic Surgery / adverse effects
  • Natural Orifice Endoscopic Surgery / methods*
  • Neurosurgical Procedures / adverse effects
  • Neurosurgical Procedures / methods*
  • Postoperative Complications / prevention & control