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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 CasesFunding The Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program within which this work was completed received the funding from Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota, Joseph and Barbara Ashkins Endowed Professorship in Surgery and Radiology, Mayo Clinic, Rochester, Minnesota and Charles B. and Ann L. Johnson Endowed Professorship in Neurosurgery, Mayo Clinic, Rochester, Minnesota.
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.
Keywordsfourth ventricle - brain tumor - posterior fossa - skull base - superior transvelar approach - suboccipital craniotomy - supracerebellar infratentorial - telovelar - transvermian
* These authors contributed equally to the article and are first co-authors.
** These authors are senior co-authors.
Received: 28 November 2022
Accepted: 17 January 2023
Accepted Manuscript online:
24 January 2023
Article published online:
24 February 2023
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- 1 Jean WC. Skull Base Surgery: Strategies. 1st ed. New York, NY: Thieme Publisher; 2019: 455
- 2 Louis DN, Perry A, Wesseling P. et al. The 2021 WHO Classification of Tumors of the Central Nervous System: a summary. Neuro-oncol 2021; 23 (08) 1231-1251
- 3 Matsushima T, Rhoton Jr AL, Lenkey C. Microsurgery of the fourth ventricle: Part 1. Microsurgical anatomy. Neurosurgery 1982; 11 (05) 631-667
- 4 Rhoton Jr AL. Cerebellum and fourth ventricle. Neurosurgery 2000; 47 (3, Suppl): S7-S27
- 5 Mussi AC, Matushita H, Andrade FG, Rhoton AL. Surgical approaches to IV ventricle–anatomical study. Childs Nerv Syst 2015; 31 (10) 1807-1814
- 6 Ezer H, Banerjee AD, Bollam P, Guthikonda B, Nanda A. The superior transvelar approach to the fourth ventricle and brainstem. J Neurol Surg B Skull Base 2012; 73 (03) 175-182
- 7 Leonel LCP, Carlstrom LP, Graffeo CS. et al. Foundations of advanced neuroanatomy: technical guidelines for specimen preparation, dissection, and 3D-photodocumentation in a surgical anatomy laboratory. J Neurol Surg B Skull Base 2021; 82 (Suppl. 03) e248-e258
- 8 Deshmukh VR, Figueiredo EG, Deshmukh P, Crawford NR, Preul MC, Spetzler RF. Quantification and comparison of telovelar and transvermian approaches to the fourth ventricle. Neurosurgery 2006;58(4, Suppl 2):ONS-202–ONS-206, discussion ONS-206–ONS-207
- 9 Grill J, Viguier D, Kieffer V. et al. Critical risk factors for intellectual impairment in children with posterior fossa tumors: the role of cerebellar damage. J Neurosurg 2004; 101 (2, Suppl): 152-158
- 10 Rekate HL, Grubb RL, Aram DM, Hahn JF, Ratcheson RA. Muteness of cerebellar origin. Arch Neurol 1985; 42 (07) 697-698
- 11 Matsushima T, Fukui M, Inoue T, Natori Y, Baba T, Fujii K. Microsurgical and magnetic resonance imaging anatomy of the cerebello-medullary fissure and its application during fourth ventricle surgery. Neurosurgery 1992; 30 (03) 325-330
- 12 Tanriover N, Ulm AJ, Rhoton Jr AL, Yasuda A. Comparison of the transvermian and telovelar approaches to the fourth ventricle. J Neurosurg 2004; 101 (03) 484-498
- 13 Tomasello F, Conti A, Cardali S, La Torre D, Angileri FF. Telovelar approach to fourth ventricle tumors: highlights and limitations. World Neurosurg 2015; 83 (06) 1141-1147
- 14 Dandy W. The brain. Practice of surgery. Hagerstown, MA: WF Prior; 1966: 452-458
- 15 Bastian AJ, Mink JW, Kaufman BA, Thach WT. Posterior vermal split syndrome. Ann Neurol 1998; 44 (04) 601-610
- 16 Holmes G. The Croonian Lectures on the clinical symptoms of cerebellar disease and their interpretation. Lecture II. 1922. Cerebellum 2007; 6 (02) 148-153 , discussion 141
- 17 Ziyal IM, Sekhar LN, Salas E. Subtonsillar-transcerebellomedullary approach to lesions involving the fourth ventricle, the cerebellomedullary fissure and the lateral brainstem. Br J Neurosurg 1999; 13 (03) 276-284
- 18 Pollack IF, Polinko P, Albright AL, Towbin R, Fitz C. Mutism and pseudobulbar symptoms after resection of posterior fossa tumors in children: incidence and pathophysiology. Neurosurgery 1995; 37 (05) 885-893
- 19 Frazier CH. Remarks upon the Surgical Aspects of Tumors of the Cerebellum. New York, NY: AR Elliott Publishing Company; 1905
- 20 Dailey AT, McKhann II GM, Berger MS. The pathophysiology of oral pharyngeal apraxia and mutism following posterior fossa tumor resection in children. J Neurosurg 1995; 83 (03) 467-475
- 21 Van Calenbergh F, Van de Laar A, Plets C, Goffin J, Casaer P. Transient cerebellar mutism after posterior fossa surgery in children. Neurosurgery 1995; 37 (05) 894-898
- 22 Law N, Greenberg M, Bouffet E. et al. Clinical and neuroanatomical predictors of cerebellar mutism syndrome. Neuro-oncol 2012; 14 (10) 1294-1303
- 23 Tamburrini G, Frassanito P, Chieffo D, Massimi L, Caldarelli M, Di Rocco C. Cerebellar mutism. Childs Nerv Syst 2015; 31 (10) 1841-1851
- 24 Matsushima T, Abe H, Kawashima M, Inoue T. Exposure of the wide interior of the fourth ventricle without splitting the vermis: importance of cutting procedures for the tela choroidea. Neurosurg Rev 2012; 35 (04) 563-571 , discussion 571–572
- 25 Mussi AC, Rhoton Jr AL. Telovelar approach to the fourth ventricle: microsurgical anatomy. J Neurosurg 2000; 92 (05) 812-823
- 26 Tomasello F, Conti A, Angileri FF, Cardali S. Telo-velar approach to fourth-ventricle tumours: how I do it. Acta Neurochir (Wien) 2015; 157 (04) 607-610
- 27 Matsushima K, Yagmurlu K, Kohno M, Rhoton Jr AL. Anatomy and approaches along the cerebellar-brainstem fissures. J Neurosurg 2016; 124 (01) 248-263
- 28 Matsushima T, Rhoton Jr AL, de Oliveira E, Peace D. Microsurgical anatomy of the veins of the posterior fossa. J Neurosurg 1983; 59 (01) 63-105
- 29 Jean WC, Abdel Aziz KM, Keller JT, van Loveren HR. Subtonsillar approach to the foramen of Luschka: an anatomic and clinical study. Neurosurgery 2003; 52 (04) 860-866 , discussion 866
- 30 Zaheer SN, Wood M. Experiences with the telovelar approach to fourth ventricular tumors in children. Pediatr Neurosurg 2010; 46 (05) 340-343
- 31 Han S, Wang Z, Wang Y, Wu A. Transcerebellomedullary fissure approach to lesions of the fourth ventricle: less is more?. Acta Neurochir (Wien) 2013; 155 (06) 1011-1016
- 32 Yaşargil MG, Abdulrauf SI. Surgery of intraventricular tumors. Neurosurgery 2008;62(6, Suppl 3):1029–1040, discussion 1040–1041
- 33 Tubbs RS, Wellons III JC, Salter G, Oakes WJ. Fenestration of the superior medullary velum as treatment for a trapped fourth ventricle: a feasibility study. Clin Anat 2004; 17 (02) 82-87
- 34 Dammers R, Delwel EJ, Krisht AF. Cavernous hemangioma of the mesencephalon: tonsillouveal transaqueductal approach. Neurosurgery 2009;64(5, Suppl 2):296–299, discussion 299–300
- 35 Farrokhi MR, Ghaffarpasand F, Taghipour M, Derakhshan N. Transventricular transvelar approach to trochlear nerve schwannoma: novel technique to lesions of inferior pineal region. World Neurosurg 2018; 114: 274-280