Abstract
Background
An anomalous subarcuate loop (SL) of the anteroinferior cerebellar artery (AICA) is a rare anatomic variation, which increases the complexity and risk of vestibular schwannoma (VS) removal. However, preoperative diagnosis of this anomaly remains difficult. The aim of this study was to report three types of anomalous SLs encountered during VS removal and to describe the “Deep Subarcuate Fossa (SF)” sign and its significance in the diagnosis and treatment of an osseous-penetrating SL.
Methods
We prospectively observed 963 patients with newly/recently diagnosed VS who underwent surgical treatment performed by the senior author (P.Z.) from 2012 to 2021 and identified 16 patients with an anomalous SL. The SF was retrospectively measured on preoperative thin-slice temporal bone computed tomography in 963 patients.
Results
Three types of anomalous SLs were encountered during VS removal: the apex of the SL was embedded in the dorsal tumor capsule (type I, 1 case), the dura (type II, 8 cases), or the dura and bone (type III, 7 cases) surrounding the SF. The depth of the SF in 7 patients with a type III anomalous SL ranged from 2.3 to 7.0 mm (3.56 ± 1.56 mm), which was significantly larger than that in 845 patients without an osseous-penetrating SL (1.23 ± 0.43 mm) (p = 0.008). When the depth of the SF exceeded 2 mm, the sensitivity and precision of the diagnosis of a type III anomalous SL were 100% (7/7) and 31.8% (7/22), respectively.
Conclusion
Three types of anomalous SLs may be encountered during VS removal, and AICA displacement is recommended before tumor removal. The “Deep SF” sign may indicate the existence of a type III anomalous SL and it can predict the depth of the AICA in the bone and guide the drilling of the bone around the vessel loop.
Similar content being viewed by others
Abbreviations
- 3D:
-
Three-dimensional
- AICA:
-
Anteroinferior cerebellar artery
- CPA:
-
Cerebellopontine angle
- CT:
-
Computed tomography
- IAM:
-
Internal acoustic meatus
- MRI:
-
Magnetic resonance imaging
- SA:
-
Subarcuate artery
- SC:
-
Subarcuate canaliculus
- SF:
-
Subarcuate fossa
- SL:
-
Subarcuate loop
- SSC:
-
Superior semicircular canal
- VS:
-
Vestibular schwannoma
References
American Academy of Otolaryngology-Head and Neck Surgery Foundation, INC (1995) Committee on Hearing and Equilibrium guidelines for the evaluation of hearing preservation in acoustic neuroma (vestibular schwannoma). Otolaryngol Head Neck Surg 113:179–180. https://doi.org/10.1016/S0194-5998(95)70101-X
Campero Á, Rasmussen J, Diloné J, Ajler P, Elizalde RL (2018) Fresado de la fosa subarcuata para liberar la arteria cerebelosa anteroinferior en una cirugía de un Schwannoma vestibular [Drilling of the subarcuate fossa to release the anterior inferior cerebellar artery in a surgery of a vestibular Schwannoma]. Surg Neurol Int 9:S66–S72. https://doi.org/10.4103/sni.sni_219_18
Candanedo C, Spektor S (2019) CPA epidermoid cyst with rare anatomic variant: anterior inferior cerebellar artery embedded in the subarcuate fossa: operative video and technical nuances. J Neurol Surg B Skull Base 80:S323–S324. https://doi.org/10.1055/s-0038-1675165
Cheng CY, Shetty R, Martinez V, Sekhar LN (2019) Microvascular decompression of facial nerve and pexy of the left vertebral artery for left hemifacial spasm: 3-dimensional operative video. Oper Neurosurg (Hagerstown) 16:E2–E3. https://doi.org/10.1093/ons/opy058
Gannon PJ, Eden AR, Laitman JT (1988) The subarcuate fossa and cerebellum of extant primates: comparative study of a skull-brain interface. Am J Phys Anthropol 77:143–164. https://doi.org/10.1002/ajpa.1330770202
Goel A, Sekhar LN (1991) Anomalous subarcuate loop. Technical note. J Neurosurg 75:985–986. https://doi.org/10.3171/jns.1991.75.6.0985
Hilding DA (1987) Petrous apex and subarcuate fossa maturation. Laryngoscope 97:1129–1135. https://doi.org/10.1288/00005537-198710000-00001
House JW, Brackmann DE (1985) Facial nerve grading system. Otolaryngol Head Neck Surg 93:146–147. https://doi.org/10.1177/019459988509300202
Martin RG, Grant JL, Peace D, Theiss C, Rhoton AL Jr (1980) Microsurgical relationships of the anterior inferior cerebellar artery and the facial-vestibulocochlear nerve complex. Neurosurgery 6:483–507. https://doi.org/10.1227/00006123-198005000-00001
Maślanka M, Skadorwa T, Ciszek B (2018) Postnatal development of the subarcuate fossa and subarcuate canaliculus—a computed tomographic study. Surg Raiol Anat 40:1111–1117. https://doi.org/10.1007/s00276-018-2045x
Proctor B (1983) The petromastoid canal. Ann Otol Rhinol Laryngol 92:640–644. https://doi.org/10.1177/000348948309200621
Rasmussen J, Plou P, Campero Á, Ajler P (2020) A classification for the anterior inferior cerebellar artery-subarcuate artery complex based on the embryological development. J Neurol Surg B Skull Base 81:536–545. https://doi.org/10.1055/s-0039-1692474
Salgado-Lopez L, Leonel LCP, Aydin SO, Peris-Celda M (2020) Surgical anatomy of the labyrinthine and subarcuate arteries and clinical implications. World Neurosurg 141:e880–e887. https://doi.org/10.1016/j.wneu.2020.06.083
Tanriover N, Rhoton AL Jr (2005) The anteroinferior cerebellar artery embedded in the subarcuate fossa: a rare anomaly and its clinical significance. Neurosurgery 57:314–319. https://doi.org/10.1227/01.neu.0000166677.70797.5e (discussion 314–319)
Tatagiba MS, Evangelista-Zamora R, Lieber S (2018) Mobilization of the anterior inferior cerebellar artery when firmly adherent to the petrous dura mater—a technical nuance in retromastoid transmeatal vestibular schwannoma surgery: 3-demensional operative video. Oper Neurosurg (Hagerstown) 15:E58–E59. https://doi.org/10.1093/ons/opy052
Tekdemir I, Aslan A, Elhan A (1999) The subarcuate canaliculus and its artery—a radioanatomical study. Ann Anat 181:207–211. https://doi.org/10.1016/S0940-9602(99)80009-0
Warren DT, Warren MD, Malfair D, Akagami R (2010) An incidence of anteroinferior cerebellar artery/posteroinferior cerebellar artery anatomic variants penetrating the subarcuate fossa dura: operative technique and identification with 3-dimensional fast imaging employing steady-state acquisition magnetic resonance imaging. Neurosurgery 66:199–203. https://doi.org/10.1227/01.NEU.0000369661.83373.33 (discussion 204)
Yamakami I, Kubota S, Higuchi Y, Ito S (2019) Challenging anterior inferior cerebellar artery in retrosigmoid vestibular schwannoma removal. World Neurosurg 121:e370–e378. https://doi.org/10.1016/j.wneu.2018.09.111
Acknowledgements
The authors thank Huijie Shen for providing the artwork and Jiawen Zhang and Dongdong Wang for help with measuring the width and depth of the SF. The authors also thank Angela Morben, DVM, ELS, from Liwen Bianji (Edanz) (www.liwenbianji.cn) for editing the English text of a draft of this manuscript.
Funding
This study was funded by the Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (CIFMS, 2019-I2M-5-008) and the Clinical Research Plan of Shanghai Hospital Development Center (No.SHDC2020CR1049B).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Ethics approval
All procedures performed were in accordance with the ethical standards of the Huashan Hospital Institutional Review Board (HIRB: KY2020-065) and with the 1964 Helsinki declaration and its later amendments. Informed consent was obtained from all individual participants included in the study.
Conflict of interest
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
This article is part of the Topical Collection on Tumor - Schwannoma
Supplementary Information
Below is the link to the electronic supplementary material.
Supplementary file2 Displacement of a type I anomalous SL encountered during removal of a left-sided vestibular schwannoma (Case 5) (MP4 60140 KB)
Supplementary file3 Displacement of a type III anomalous SL encountered during removal of a left-sided vestibular schwannoma (Case 9) (MP4 80842 KB)
Rights and permissions
About this article
Cite this article
Xu, M., Xu, J., Chen, M. et al. The “Deep Subarcuate Fossa” sign and three types of anomalous subarcuate loops encountered during vestibular schwannoma removal. Acta Neurochir 164, 2483–2490 (2022). https://doi.org/10.1007/s00701-022-05288-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00701-022-05288-6