the SKUBA meningioma CLASSIFICATIon

Petroclival meningioma (PCM)

PCMs originate at or medial to the skull base foramina of cranial nerves V through XI, extend to the tentorium, and have their primary base at the petroclival fissure (PCF). [1,2,3,4,5,6,7,8,9,10,11] Anatomically, this encompasses the upper two-thirds of the clivus, lateral to the midline, including the posterior clinoid processes and dorsum sellae, down to the jugular foramen. It excludes meningiomas emanating from the lower third of the clivus, medial to the hypoglossal canal. [5,6] PMCs can be subdivided into the following types: [7]

  • PCp type: Posterior. PCMs are localized almost exclusively in the PCF with no or minimal extension into the Meckel cave. They bulge into the cerebellopontine angle without supratentorial extension.
  • PC type: PCMs with supra- and subtentorial growth, extending below the internal acoustic meatus and invading the Meckel cave and the posterior portion of the cavernous sinus.
  • PCm type: Middle, sphenopetroclival. PCMs straddling the petrous ridge but prevalently extending into the middle cranial fossa, with invasion of the anterior cavernous sinus.
  • PC+ type: types PC and PCm. Large PCMs occupying both the PCF and the middle cranial fossa with supra- and subtentorial extension and extension below the internal acoustic meatus. The PCMs also invade both the posterior and anterior portions of the cavernous sinus.


Vascularisation

PCMs get their blood supply from the branch of the meningohypophyseal trunk branch of the ICA, the subarcuate artery branch of the AICA, the medial clival artery branch of the cavernous carotid, the jugular branch of the occipital artery and/or from the jugular branch of the ascending pharyngeal artery. [12]


Cranial Nerve Involvement

PMCs tend to dislocate the CNs III, IV upwardly; the CNs V, VII, VIII, IX, X, XI posteriorly and laterally; the CN VI medially ; and the brainstem medially and posteriorly. [1,3,13]

  1. Beer-Furlan A, Vellutini EA, Gomes MQT, Cardoso AC, Prevedello LM, Todeschini AB, Prevedello DM. Approach Selection and Surgical Planning in Posterior Cranial Fossa Meningiomas: How I Do It. J Neurol Surg B Skull Base. 2019 August. 80(4). 380-391.
  2. Mastantuoni C, Cavallo L, Esposito F, d’Avella E, de Divitiis O, Somma T, et al. Midline Skull Base Meningiomas: Transcranial and Endonasal Perspectives. Cancers (Basel). June 2022. 14(12).2878.
  3. Ramina R. Fernandes YB. Coelho Neto M. Da Silva LFM Jr. Samii’s essentials in Neurosurgery. Second Edition. Chapter 19: Petroclival Meningiomas: Diagnosis, treatment, and Results. 199-216. Berlin, Heidelberg. Springer. 2014.
  4. Couldwell W, Weiss M. Surgical Approaches to Petroclival meningioas Part I: Upper and Midclival Approaches. Contemporary Neurosurgery. 1994. 16(12). 1-6.
  5. Couldwell W, Fukushima T, Giannotta S, Weiss M. Petroclival meningiomas: surgical experience in 109 cases. J Neurosurg. January 1996. 84(1). 20-28.
  6. McElveen Jr JT, Dorfman BE, Fukushima T. Petroclival tumors: a synthesis. Otolaryngol Clin North Am. 2001 December. 34(6). 1219-1230.
  7. Sassun T, Ruggeri A, Delfini R. True Petroclival Meningiomas: Proposal of Classification and Role of the Combined Supra-Infratentorial Presigmoid Retrolabyrinthine Approach. World Neurosurg. December 2016. 96. 111-123.
  8. Almefty R, Dunn I, Pravdenkova S, Abolfotoh M, Al-Mefty O. True petroclival meningiomas: results of surgical management. J Neurosurg. January 2014. 120(1). 40-51.
  9. Wayhs S. Lepski G, Frighetto L, Isolan G. Petroclival meningiomas: Remaining controversies in light of minimally invasive approaches. Clin Neurol Neurosurg. January 2017. 152. 68-75.
  10. Maurer A, Safavi-Abbasi S, Cheema A, Glenn C, Sughrue M. Management of Petroclival Meningiomas: A Review of the Development of Current Therapy. J Neurol Surg B Skull Base. October 2014. 75(5). 358-367.
  11. Altieri R, Samashima T, Pacca P, Crobeddu E, Garbossa D, Ducati A, Zenga F. Detailed anatomy knowledge: first step to approach petroclival meningiomas through the petrous apex. Anatomy lab experience and surgical series. Neurosurg Rev. April 2017. 40(2). 231-239.
  12. The Rhoton Collection. [Internet]. Available from: http://rhoton.ineurodb.org/?page=21899. Accessed 6th October 2023.
  13. Isolan G, Wayhs S, Lepski G, Dini L, Lavinsky J. Petroclival Meningiomas: Factors Determining the Choice of Approach. J Neurol Surg B Skull Base. August 2018. 79(4). 367-378.