Acta Neurochirurgica

, Volume 156, Issue 2, pp 403–408 | Cite as

The relationship between nervus intermedius anatomy, ultrastructure, electrophysiology, and clinical function. Usefulness in cerebellopontine microsurgery

  • Alex Alfieri
  • Stefan Rampp
  • Christian Strauss
  • Julius Fleischhammer
  • Jens Rachinger
  • Christian Scheller
  • Julian Prell
Clinical Article - Neurosurgical Anatomy



Although previous studies have described the clinical features of the nervus intermedius (NI), no attempt has yet been made to describe the relationship between the ultrastructural and electrophysiological characteristics of the nervus intermedius and its motor competence.


In this study, we analyzed the intraoperative electrophysiological response obtained during vestibular schwannoma surgery. The ultrastructure was studied using electron microscopy.

Materials and Methods

Thirty-six consecutive patients underwent microsurgery for vestibular schwannoma with cerebellopontine angle tumors. The patients were extensively monitored intraoperatively. Selective stimulation of the nervus intermedius was attempted in all cases. The patients were then examined postoperatively and followed for a minimum of 1 year. Forty-three isolated human brainstems were analyzed to collect the ultrastructural NI data.


We found a correlation between the NI motor responses in the perinasal and perioral regions and the ultrastructure characteristics, with few (0.5 %) but large myelinated motor fibers (diameters >12 μm). Both characteristics are consistent with the clinical observation of transient weakness of the levator anguli oris muscle. These observations indicate a relationship between the intraoperative electrophysiological identification of the NI nervus intermedius and its clinical and ultrastructural characteristics.


Identifying the NI in the deformed anatomy of tumors could provide a fixed landmark during cerebellopontine surgery and help prevent damage of the facial nerve.


Facial nerve Acoustic neuroma Vestibular schwannoma Cerebellopontine surgery Intraoperative neuromonitoring Electron microscopy 



Drs. Alfieri and Rampp contributed equally to the study. We are grateful to Mr. Heine and Dr. Litvak for their remarkable contribution to this study. The patient authorized the publication of the images.

Conflicts of interest



Wilhelm Roux Foundation, Martin Luther University Halle-Wittenberg, Germany


  1. 1.
    Alfieri A, Fleischhammer J, Peschke E, Strauss C (2012) The nervus intermedius as a variable landmark and critical structure in cerebellopontine angle surgery: an anatomical study and classification. Acta Neurochir 154(7):1263–1268PubMedCrossRefGoogle Scholar
  2. 2.
    Alfieri A, Fleischhammer J, Prell J (2011) The functions of the nervus intermedius. AJNR 32(7):E144PubMedCrossRefGoogle Scholar
  3. 3.
    Alfieri A, Strauss C, Prell J, Peschke E (2010) History of the nervus intermedius of Wrisberg. Ann Anat 192(3):139–144PubMedCrossRefGoogle Scholar
  4. 4.
    Ashram YA, Jackler RK, Pitts LH, Yingling CD (2005) Intraoperative electrophysiologic identification of the nervus intermedius. Otol Neurotol 26(2):274–279PubMedCrossRefGoogle Scholar
  5. 5.
    Irving RM, Viani L, Hardy DG, Baguley DM, Moffat DA (1995) Nervus intermedius function after vestibular schwannoma removal: clinical features and pathophysiological mechanisms. Laryngoscope 105(8 Pt 1):809–813PubMedCrossRefGoogle Scholar
  6. 6.
    Manzano GM, Giuliano LM, Nobrega JA (2008) A brief historical note on the classification of nerve fibers. Arq Neuropsiquiatr 66(1):117–119PubMedCrossRefGoogle Scholar
  7. 7.
    Myrseth E, Moller P, Pedersen PH, Lund-Johansen M (2009) Vestibular schwannoma: surgery or Gamma knife radiosurgery? A prospective, nonrandomized study. Neurosurgery 64(4):654–661PubMedCrossRefGoogle Scholar
  8. 8.
    Ozer FD, Duransoy YK, Camlar M (2009) Atypic geniculate neuralgia: atypic anatomic correlation of cranial nerve roots and AICA. Acta Neurochir 151(8):1003–1004PubMedCrossRefGoogle Scholar
  9. 9.
    Park SH, Lee KY, Hwang SK (2013) Nervus intermedius dysfunction following Gamma Knife surgery for vestibular schwannoma. J Neurosurg 118(3):566–570PubMedCrossRefGoogle Scholar
  10. 10.
    Prell J, Rampp S, Rachinger J, Scheller C, Naraghi R, Strauss C (2008) Spontaneous electromyographic activity during microvascular decompression in trigeminal neuralgia. J Clin Neurophysiol 25(4):225–232PubMedCrossRefGoogle Scholar
  11. 11.
    Prell J, Rachinger J, Scheller C, Alfieri A, Strauss C, Rampp S (2010) A real-time monitoring system for the facial nerve. Neurosurgery 66(6):1064–1073PubMedCrossRefGoogle Scholar
  12. 12.
    Prell J, Rampp S, Romstock J, Fahlbusch R, Strauss C (2007) Train time as a quantitative electromyographic parameter for facial nerve function in patients undergoing surgery for vestibular schwannoma. J Neurosurg 106(5):826–832PubMedCrossRefGoogle Scholar
  13. 13.
    Rampp S, Rachinger J, Scheller C, Alfieri A, Strauss C, Prell J (2012) How many electromyography channels do we need for facial nerve monitoring? J Clin Neurophysiol 29(3):226–229PubMedCrossRefGoogle Scholar
  14. 14.
    Rhoton AL Jr, Kobayashi S, Hollinshead WH (1968) Nervus intermedius. J Neurosurg 29(6):609–618PubMedCrossRefGoogle Scholar
  15. 15.
    Sachs E Jr (1968) The role of the nervus intermedius in facial neuralgia. Report of four cases with observations on the pathways for taste, lacrimation, and pain in the face. J Neurosurg 28(1):54–60PubMedCrossRefGoogle Scholar
  16. 16.
    Samii M, Gerganov VM, Samii A (2010) Functional outcome after complete surgical removal of giant vestibular schwannomas. J Neurosurg 112(4):860–867PubMedCrossRefGoogle Scholar
  17. 17.
    Scheller C, Rachinger J, Prell J, Kornhuber M, Strauss C (2008) Schwannoma of the intermediate nerve. J Neurosurg 109(1):144–148PubMedCrossRefGoogle Scholar
  18. 18.
    Stripf T, Braun K, Gouveris H, Stripf EA, Mann WJ, Amedee RG (2007) Influence of different approaches to the cerebellopontine angle on the function of the intermediate nerve. J Neurosurg 107(5):927–931PubMedCrossRefGoogle Scholar
  19. 19.
    Tubbs RS, Mosier KM, Cohen-Gadol AA (2012) Geniculate neuralgia: clinical, radiologic, and intraoperative correlates. World Neurosurg 79(5–6):763–767PubMedGoogle Scholar

Copyright information

© Springer-Verlag Wien 2013

Authors and Affiliations

  • Alex Alfieri
    • 1
  • Stefan Rampp
    • 2
  • Christian Strauss
    • 2
  • Julius Fleischhammer
    • 2
  • Jens Rachinger
    • 2
  • Christian Scheller
    • 2
  • Julian Prell
    • 2
  1. 1.Neurosurgery and Spinal SurgeryNeuruppinGermany
  2. 2.Department of NeurosurgeryMartin Luther University Halle-WittenbergHalle (Saale)Germany

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