Child's Nervous System

, Volume 34, Issue 9, pp 1745–1752 | Cite as

Surgical anatomy of lateral recess in paediatric auditory brainstem implant patients and its clinical correlates including grades of flocculus

  • Shyam Sundar KrishnanEmail author
  • Pulak Nigam
  • Poonam Mohanty
  • Madabhushi Chakravarthy Vasudevan
  • Mohan Kameswaran
Original Paper



Auditory brainstem implant (ABI), a standard technique in treatment of profound sensorineural hearing loss in patients with neurofibromatosis 2, is now being increasingly employed in children with congenital bilateral sensorineural hearing loss, as in Michele’s deformity. A detailed knowledge of the relevant surgical anatomy of the lateral recess and its anatomical landmarks including the flocculus, the choroid plexus and the root entry zones of facial-vestibulocochlear and glossopharyngeal-vagus nerve complexes and their anatomical variants is mandatory, as it is the conduit for electrode array placement. The placement of electrode may be eased or impeded by these variations.

Materials and methods

Thirty-two children with congenital bilateral hearing loss underwent surgery through retromastoid suboccipital approach for placement of auditory brainstem implant. The preoperative anatomy was reviewed in detail during procedure and again later in the operative videos.


The flocculus was classified into four grades based on its anatomy and relations. Among these, grade II (11 children) was the commonest while grade IV (five children) was least common. Choroid plexus was variable in size across grades of flocculus. Difficulty in defining the anatomy was significantly more (p value = 0.003) in the group with higher grade flocculus (grade III and IV) than in lower grade flocculus (grade I and II).


The flocculus in these patients is classifiable into one of the four grades and the surgical nuances such as difficulty in defining the anatomy for placement of ABI are dependent on the characteristics exhibited by the floccular anatomy and relations.


Flocculus Lateral recess Choroid plexus Auditory brainstem implant 


Compliance with ethical standards

Conflict of interest

All authors certify that they have no affiliations with or involvement in any organisation or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licencing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (Institutional Ethics Committee, Voluntary Health Services Multi-speciality Hospital & Research Centre, Chennai) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


  1. 1.
    Goyal S, Krishnan SS, Kameswaran M, Vasudevan MC, Ranjith, Natarajan K (2017) Does cerebellar flocculus size affect subjective outcomes in pediatric auditory brainstem implantation. Int J Pediatr Otorhinolaryngol 97:30–34. CrossRefPubMedGoogle Scholar
  2. 2.
    Friedland DR, Wackym PA (1999) Evaluation of surgical approaches to endoscopic auditory brainstem implantation. Laryngoscope 109:175–180CrossRefPubMedGoogle Scholar
  3. 3.
    Colletti V, Fiorino FG, Carner M, Giarbini N, Sacchetto L, Cumer G (2000) Advantages of the retrosigmoid approach in auditory brain stem implantation. Skull Base Surg 10:165–170CrossRefPubMedPubMedCentralGoogle Scholar
  4. 4.
    Blanchfield BB, Feldman JJ, Dunbar JL, Gardner EN (2001) The severely to profoundly hearing-impaired population in the United States: prevalence estimates and demographics. J Am Acad Audiol 12:183–189PubMedGoogle Scholar
  5. 5.
    Carney AE, Moeller MP (1998) Treatment efficacy: hearing loss in children. J Speech Lang Hear Res 41:S61–S84CrossRefPubMedGoogle Scholar
  6. 6.
    Froehlinger VJ, Alexander Graham Bell Association for the Deaf (1981) Today’s hearing-impaired child—into the mainstream of education: a practical guide for preschool and elementary teachers, parents, and administrators. Alexander Graham Bell Association for the Deaf, Washington, D.CGoogle Scholar
  7. 7.
    Fayad JN, Otto SR, Brackmann DE (2006) Auditory brainstem implants: surgical aspects. Adv Otorhinolaryngol 64:144–153. PubMedCrossRefGoogle Scholar
  8. 8.
    Brackmann DE, Hitselberger WE, Nelson RA, Moore J, Waring MD, Portillo F, Shannon RV, Telischi FF (1993) Auditory brainstem implant: I. Issues in surgical implantation. Otolaryngol Head Neck Surg 108:624–633. CrossRefPubMedGoogle Scholar
  9. 9.
    Colletti V, Shannon R, Carner M, Sacchetto L, Turazzi S, Masotto B, Colletti L (2007) The first successful case of hearing produced by electrical stimulation of the human midbrain. Otol Neurotol 28:39–43. CrossRefPubMedGoogle Scholar
  10. 10.
    Dobelle WH, Stensaas SS, Mladejovsky MG, Smith JB (1973) A prosthesis for the deaf based on cortical stimulation. Ann Otol Rhinol Laryngol 82:445–463. CrossRefPubMedGoogle Scholar
  11. 11.
    Edgerton BJ, House WF, Hitselberger W (1982) Hearing by cochlear nucleus stimulation in humans. Ann Otol Rhinol Laryngol Suppl 91:117–124PubMedGoogle Scholar
  12. 12.
    Eisenberg LS, Maltan AA, Portillo F, Mobley P, House WF (1987) Electrical stimulation of the auditory brain stem structure in deafened adults. J Rehabil Res Dev 24:9–22CrossRefPubMedGoogle Scholar
  13. 13.
    Heller JW, Brackmann DE, Tucci DL, Nyenhuis JA, Chou CK (1996) Evaluation of MRI compatibility of the modified nucleus multichannel auditory brainstem and cochlear implants. Am J Otol 17:724–729PubMedGoogle Scholar
  14. 14.
    Lim HH, Lenarz T, Anderson DJ, Lenarz M (2008) The auditory midbrain implant: effects of electrode location. Hear Res 242:74–85. CrossRefPubMedGoogle Scholar
  15. 15.
    Merkus P, Di Lella F, Di Trapani G et al (2014) Indications and contraindications of auditory brainstem implants: systematic review and illustrative cases. Eur Arch Otorhinolaryngol 271:3–13. CrossRefPubMedGoogle Scholar
  16. 16.
    Otto SR, Brackmann DE, Hitselberger WE, Shannon RV, Kuchta J (2002) Multichannel auditory brainstem implant: update on performance in 61 patients. J Neurosurg 96:1063–1071. CrossRefPubMedGoogle Scholar
  17. 17.
    Portillo F, Nelson RA, Brackmann DE et al (1993) Auditory brain stem implant: electrical stimulation of the human cochlear nucleus. Adv Otorhinolaryngol 48:248–252PubMedGoogle Scholar
  18. 18.
    Schwartz MS, Otto SR, Brackmann DE, Hitselberger WE, Shannon RV (2003) Use of a multichannel auditory brainstem implant for neurofibromatosis type 2. Stereotact Funct Neurosurg 81:110–114CrossRefPubMedGoogle Scholar
  19. 19.
    Simmons FB, Mongeon CJ, Lewis WR, Huntington DA (1964) Electrical stimulation of acoustical nerve and inferior colliculus. Arch Otolaryngol Chic Ill 79:559–568CrossRefGoogle Scholar
  20. 20.
    Cai S, Ma W-LD, Young ED (2009) Encoding intensity in ventral cochlear nucleus following acoustic trauma: implications for loudness recruitment. J Assoc Res Otolaryngol 10:5–22. CrossRefPubMedGoogle Scholar
  21. 21.
    Colletti V, Shannon R, Carner M, Veronese S, Colletti L (2009) Outcomes in nontumor adults fitted with the auditory brainstem implant: 10 years’ experience. Otol Neurotol 30:614–618. CrossRefPubMedGoogle Scholar
  22. 22.
    Colletti V, Shannon RV (2005) Open set speech perception with auditory brainstem implant? Laryngoscope 115:1974–1978. CrossRefPubMedGoogle Scholar
  23. 23.
    Grayeli AB, Kalamarides M, Bouccara D, Ambert-Dahan E, Sterkers O (2008) Auditory brainstem implant in neurofibromatosis type 2 and non-Neurofibromatosis type 2 patients. Otol Neurotol 29:1140–1146. CrossRefPubMedGoogle Scholar
  24. 24.
    Lim HH, Lenarz M, Lenarz T (2009) Auditory midbrain implant: a review. Trends Amplif 13:149–180. CrossRefPubMedPubMedCentralGoogle Scholar
  25. 25.
    Sanna M, Di Lella F, Guida M, Merkus P (2012) Auditory brainstem implants in NF2 patients: results and review of the literature. Otol Neurotol 33:154–164. CrossRefPubMedGoogle Scholar
  26. 26.
    Schwartz MS, Otto SR, Shannon RV, Hitselberger WE, Brackmann DE (2008) Auditory brainstem implants. Neurother J Am Soc Exp Neurother 5:128–136. CrossRefGoogle Scholar
  27. 27.
    Siegbahn M, Lundin K, Olsson G-B, Stillesjö F, Kinnefors A, Rask-Andersen H, Nyberg G (2014) Auditory brainstem implants (ABIs)—20 years of clinical experience in Uppsala, Sweden. Acta Otolaryngol (Stockh) 134:1052–1061. CrossRefGoogle Scholar
  28. 28.
    Colletti V, Carner M, Miorelli V, Guida M, Colletti L, Fiorino F (2005) Auditory brainstem implant (ABI): new frontiers in adults and children. Otolaryngol Head Neck Surg 133:126–138. CrossRefPubMedGoogle Scholar
  29. 29.
    Komune N, Yagmurlu K, Matsuo S, Miki K, Abe H, Rhoton AL Jr (2015) Auditory brainstem implantation: anatomy and approaches. Neurosurgery 11:306–321. CrossRefPubMedGoogle Scholar
  30. 30.
    Johal J, Paulk PB, Oakes PC, Oskouian RJ, Loukas M, Tubbs RS (2017) A comprehensive review of the foramina of Luschka: history, anatomy, embryology, and surgery. Childs Nerv Syst 33:1459–1462. CrossRefPubMedGoogle Scholar
  31. 31.
    Matsushima T, Rhoton AL, Lenkey C (1982) Microsurgery of the fourth ventricle: part 1. Microsurgical anatomy. Neurosurgery 11:631–667CrossRefPubMedGoogle Scholar
  32. 32.
    Seki Y, Samejima N, Kumakawa K, Komatsuzaki A (2003) Subtonsillar placement of auditory brainstem implant. Acta Neurochir Suppl 87:85–87PubMedGoogle Scholar
  33. 33.
    Shofner WP, Young ED (1985) Excitatory/inhibitory response types in the cochlear nucleus: relationships to discharge patterns and responses to electrical stimulation of the auditory nerve. J Neurophysiol 54:917–939CrossRefPubMedGoogle Scholar
  34. 34.
    Bento RF, Brito Neto RV, Tsuji RK et al (2008) Auditory brainstem implant: surgical technique and early audiological results in patients with neurofibromatosis type 2. Braz J Otorhinolaryngol 74:647–651CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Shyam Sundar Krishnan
    • 1
    Email author
  • Pulak Nigam
    • 1
  • Poonam Mohanty
    • 1
  • Madabhushi Chakravarthy Vasudevan
    • 1
  • Mohan Kameswaran
    • 2
  1. 1.Dr. Achantha Lakshmipathi Neurosurgical Centre, Post Graduate Institute of Neurological SurgeryVoluntary Health Services Multi-Speciality Hospital & Research CentreChennaiIndia
  2. 2.Madras ENT Research FoundationChennaiIndia

Personalised recommendations