Anatomical Step-by-Step Dissection of Midline Suboccipital Approaches to the Fourth Ventricle for Trainees: Surgical Anatomy of the Telovelar, Transvermian, and Superior Transvelar Routes, Surgical Principles, and Illustrative Cases

Danielle D. Dang; Julian S. Rechberger; Luciano C.P.C. Leonel; Hana Hallak; Stephen Graepel; Michael J. Link; David J. Daniels; Maria Peris-Celda

doi:10.1055/a-2018-4745

Journal of Neurological Surgery Part B: Skull Base, Table of Contents

J Neurol Surg B Skull Base 2024; 85(02): 172-188
DOI: 10.1055/a-2018-4745

Original Article

Anatomical Step-by-Step Dissection of Midline Suboccipital Approaches to the Fourth Ventricle for Trainees: Surgical Anatomy of the Telovelar, Transvermian, and Superior Transvelar Routes, Surgical Principles, and Illustrative Cases

Authors

Danielle D. Dang‡^*

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

²Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, United States
Julian S. Rechberger‡^*

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

²Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, United States
Luciano C.P.C. Leonel

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

²Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, United States
Hana Hallak

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

²Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, United States
Stephen Graepel

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States
Michael J. Link

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

²Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, United States

³Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, United States
David J. Daniels^**

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States
Maria Peris-Celda^**

¹Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States

²Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Mayo Clinic, Rochester, Minnesota, United States

³Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, United States

Abstract

Introduction Safe, effective access to the fourth ventricle for oncologic resection remains challenging given the depth of location, restricted posterior fossa boundaries, and surrounding eloquent neuroanatomy. Despite description in the literature, a practical step-by step dissection guide of the suboccipital approaches to the fourth ventricle targeted to all training levels is lacking.

Methods Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic visualization. Dissections of the telovelar, transvermian, and supracerebellar infratentorial-superior transvelar approaches were performed by one neurosurgery resident (D.D.D.), under guidance of senior authors. The dissections were supplemented with representative clinical cases to highlight pertinent surgical principles.

Results The telovelar and transvermian corridors afford excellent access to the caudal two-thirds of the fourth ventricle with the former approach offering expanded access to the lateral recess, foramen of Luschka, adjacent skull base, and cerebellopontine angle. The supracerebellar infratentorial-superior transvelar approach reaches the rostral third of the fourth ventricle, the cerebral aqueduct, and dorsal mesencephalon. Key steps described include positioning and skin incision, myofascial dissection, burr hole and craniotomy, durotomy, the aforementioned transventricular routes, and identification of relevant skull base landmarks.

Conclusion The midline suboccipital craniotomy represents a foundational cranial approach, particularly for lesions involving the fourth ventricle. Operatively oriented resources that combine stepwise neuroanatomic dissections with representative cases provide a crucial foundation for neurosurgical training. We present a comprehensive guide for trainees in the surgical anatomy laboratory to optimize familiarity with fourth ventricle approaches, mastery of relevant microsurgical anatomy, and simultaneous preparation for learning in the operating room.

Keywords

fourth ventricle - brain tumor - posterior fossa - skull base - superior transvelar approach - suboccipital craniotomy - supracerebellar infratentorial - telovelar - transvermian

Full Text

References

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