Evaluation of Variations of the Chorda Tympani Nerve Originating from The Facial Nerve on High Resolution CT
Abstract
Objective: The aim of this study is to define the anatomical variations of the chorda tympani nerve originating from the facial nerve on high resolution CT (HRCT).
Method: A retrospective study of 100 patients who underwent temporal bone HRCT imaging in Duzce University, Department of Radiology. Individuals with normal bone structure at least on one side, were included in the study. Multiplanar reconstruction images were created then chorda tympani was imaged and measurements were performed.
Results: Thirty-seven bone were excluded. When the originating localizations of the chorda tympani from the facial nerve were examined, 19(11.7%) anterior, 85(52.1%) anterolateral, 55(33.7%) lateral and 4(2.5%) posterolateral origins. The distance from the origin of the chorda tympani to the stylomastoid foramen was measured as 3.7±1.6 mm. The originating angle of the chorda tympani from the facial nerve was measured as 28.2±10.7º. The widest distance between the chorda tympani and the mastoid segment of the facial nerve was measured as 2.3±0.6mm. The furthest distance between the mastoid segment of the facial nerve and chorda tympani is inversely correlated with the distance between chorda tympani
and stylomastoid foramen. The angle of originating chorda tympani from facial nerve is directly correlated with the distance between chorda tympani and stylomastoid foramen. The ratio of extratemporal branching of chorda tympani is %2.4.
Conclusions: The chorda tympani can be clearly seen on axial and reformat images on HRCT. Preoperative evaluation of the chorda tympani nerve might help to plan the surgical approach and thus prevent iatrogenic injury during middle ear surgery
Keywords
Chorda Tympani Facial Recess High Resolution CT Facial Nerve Posterior Tympanotomy Temporal Bone
References
- 1- McManus LJ, Stringer MD, Dawes PJ. Iatrogenic injury of the chorda tympani: a systematic review. J Laryngol Otol. 2012;126(1):8–14.
- 2- Choi N, Ahn J, Cho YS. Taste changes in patients with middle ear surgery by intraoperative manipulation of chorda tympani nerve. Otol Neurotol. 2018;39(5):591–6.
- 3- Erovic BM, Chan HH, Daly MJ, Pothier DD, Yu E, Coulson C, et al. Intraoperative cone-beam computed tomography and multi-slice computed tomography in temporal bone imaging for surgical treatment. Otolaryngol Head Neck Surg. 2014;150(1):107–14.
- 4- Singh D, Hsu CC, Kwan GN, Bhuta S, Skalski M, Jones R. High-resolution CT study of the chorda tympani nerve and normal anatomical variation. Jpn J Radiol. 2015;33(5):279–86.
- 5- Parlier-Cuau C, Champsaur P, Perrin E, Rabischong P, Lassau JP. High-resolution computed tomography of the canals of the temporal bone: anatomic correlations. Surg Radiol Anat. 1998;20(6):437–44.
- 6- Jeon EJ, Oh SH, Kim JH, Lee HS, Lee DS, Chung JW. Surgical and radiologic anatomy of a cochleostomy produced via posterior tympanotomy for cochlear implantation based on three-dimensional reconstructed temporal bone CT images. Surg Radiol Anat. 2013;35(6):471–5.
- 7- Kim CW, Kwon OJ, Park JH, Park YH. Posterior tympanotomy is a riskier procedure in chronic otitis media than in a normal mastoid: a high-resolution computed tomography study. Surg Radiol Anat. 2016;38(6):717–21.
- 8- Wang L, Yang H, Wu H, Jiang H. Cochlear implantation surgery in patients with narrow facial recess. Acta Otorhinolaryngol Ital. 2013;133(9):935–8.
- 9- Fujita S, Nishizawa S, Yagihashi T, Tohma H. Postnatal developmental changes in facial nerve morphology. Eur Arch Otorhinolaryngol. 1994;251(7):434–8.
- 10- Zou T, Xie N, Guo M, Shu F, Zhang H. [Title in original language]. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2012;26(10):445–8.
- 11- Low WK. Surgical anatomy of the facial nerve in Chinese mastoids. ORL J Otorhinolaryngol Relat Spec. 1999;61(6):341–4.
- 12- Kulczyński B, Woźniak W. Variation of the origin and course of the chorda tympani. Folia Morphol. 1977;37(3):237–41.
- 13- Muren C, Wadin K, Wilbrand HF. Anatomic variations of the chorda tympani canal. Acta Otorhinolaryngol. 1990;110(3–4):262–5.
- 14- Kullman GL, Dyck PJ, Cody DTR. Anatomy of the mastoid portion of the facial nerve. Arch Otolaryngol. 1971;93(1):29–33.
- 15- Calli C, Ugur MB, Onur E, Adanir S, Ozturk E, Karatas A, et al. Measurements of the facial recess anatomy: implications for sparing the facial nerve and chorda tympani during posterior tympanotomy. Ear Nose Throat J. 2010;89(10):490.
- 16- Shin KJ, Lee SH, Kim SS, Kim SW, Kim JY, Cho JH, et al. Three-dimensional study of the facial canal using microcomputed tomography for improved anatomical comprehension. Anat Rec. 2014;297(10):1808–16.
Korda Timpani’nin Fasiyal Sinirden Çıkış Varyasyonlarının Yüksek Çözünürlüklü BT’ de Değerlendirilmesi
Abstract
Amaç: Bu çalışmanın amacı, fasiyal sinirden köken alan korda timpani sinirinin anatomik varyasyonlarını yüksek çözünürlüklü BT' de (HRCT) tanımlamaktır.
Yöntem: Düzce Üniversitesi Radyoloji Anabilim Dalı' nda temporal kemik HRCT görüntülemesi yapılan 100 hastanın görüntüleri retrospektif olarak değerlendirildi. En azından bir tarafta normal temporal kemik yapısına sahip bireyler çalışmaya dahil edildi. Multiplanar rekonstrüksiyon görüntüleri oluşturulduktan sonra korda timpani görüntülendi ve ölçümler yapıldı.
Bulgular: 200 temporal kemikten 37'si çalışma dışında tutuldu. Korda timpaninin fasiyal sinirden çıkış lokalizasyonları incelendiğinde, 19 (%11,7) anterior, 85 (%52,1) anterolateral, 55 (%33,7) lateral ve 4 (%2,5) posterolateral orijinliydi. Korda timpaninin orijini ile stilomastoid foramen arası mesafe 3.7±1.6 mm olarak ölçüldü. Korda timpaninin fasiyal sinirden çıkış açısı 28.2±10.7º olarak ölçüldü. Korda timpani ile fasiyal sinirin mastoid segmenti arasındaki en geniş mesafe 2.3±0.6 mm olarak ölçüldü. Fasiyal sinirin mastoid segmenti - korda timpani arasındaki en uzak mesafe ile korda timpani - stilomastoid foramen arasındaki mesafe ters orantılıdır. Korda timpaninin fasiyal sinirden çıkış açısı, korda timpani ile stilomastoid foramen arasındaki mesafe doğrudan ilişkilidir. Korda timpaninin ekstratemporal dallanma oranı %2,4'tür.
Sonuç: Korda timpani, HRCT' de aksiyel ve reformat görüntülerde açıkça görülebilir. Korda timpaninin operasyon öncesi değerlendirilmesi, cerrahi yaklaşımı planlamaya ve böylece orta kulak cerrahisi sırasında iatrojenik yaralanmayı önlemeye yardımcı olabilir.
Keywords
Korda Timpani Fasiyal Reses Yüksek Çözünürlüklü BT Fasiyal Sinir Posterior Timpanotomi Temporal Kemik
References
- 1- McManus LJ, Stringer MD, Dawes PJ. Iatrogenic injury of the chorda tympani: a systematic review. J Laryngol Otol. 2012;126(1):8–14.
- 2- Choi N, Ahn J, Cho YS. Taste changes in patients with middle ear surgery by intraoperative manipulation of chorda tympani nerve. Otol Neurotol. 2018;39(5):591–6.
- 3- Erovic BM, Chan HH, Daly MJ, Pothier DD, Yu E, Coulson C, et al. Intraoperative cone-beam computed tomography and multi-slice computed tomography in temporal bone imaging for surgical treatment. Otolaryngol Head Neck Surg. 2014;150(1):107–14.
- 4- Singh D, Hsu CC, Kwan GN, Bhuta S, Skalski M, Jones R. High-resolution CT study of the chorda tympani nerve and normal anatomical variation. Jpn J Radiol. 2015;33(5):279–86.
- 5- Parlier-Cuau C, Champsaur P, Perrin E, Rabischong P, Lassau JP. High-resolution computed tomography of the canals of the temporal bone: anatomic correlations. Surg Radiol Anat. 1998;20(6):437–44.
- 6- Jeon EJ, Oh SH, Kim JH, Lee HS, Lee DS, Chung JW. Surgical and radiologic anatomy of a cochleostomy produced via posterior tympanotomy for cochlear implantation based on three-dimensional reconstructed temporal bone CT images. Surg Radiol Anat. 2013;35(6):471–5.
- 7- Kim CW, Kwon OJ, Park JH, Park YH. Posterior tympanotomy is a riskier procedure in chronic otitis media than in a normal mastoid: a high-resolution computed tomography study. Surg Radiol Anat. 2016;38(6):717–21.
- 8- Wang L, Yang H, Wu H, Jiang H. Cochlear implantation surgery in patients with narrow facial recess. Acta Otorhinolaryngol Ital. 2013;133(9):935–8.
- 9- Fujita S, Nishizawa S, Yagihashi T, Tohma H. Postnatal developmental changes in facial nerve morphology. Eur Arch Otorhinolaryngol. 1994;251(7):434–8.
- 10- Zou T, Xie N, Guo M, Shu F, Zhang H. [Title in original language]. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2012;26(10):445–8.
- 11- Low WK. Surgical anatomy of the facial nerve in Chinese mastoids. ORL J Otorhinolaryngol Relat Spec. 1999;61(6):341–4.
- 12- Kulczyński B, Woźniak W. Variation of the origin and course of the chorda tympani. Folia Morphol. 1977;37(3):237–41.
- 13- Muren C, Wadin K, Wilbrand HF. Anatomic variations of the chorda tympani canal. Acta Otorhinolaryngol. 1990;110(3–4):262–5.
- 14- Kullman GL, Dyck PJ, Cody DTR. Anatomy of the mastoid portion of the facial nerve. Arch Otolaryngol. 1971;93(1):29–33.
- 15- Calli C, Ugur MB, Onur E, Adanir S, Ozturk E, Karatas A, et al. Measurements of the facial recess anatomy: implications for sparing the facial nerve and chorda tympani during posterior tympanotomy. Ear Nose Throat J. 2010;89(10):490.
- 16- Shin KJ, Lee SH, Kim SS, Kim SW, Kim JY, Cho JH, et al. Three-dimensional study of the facial canal using microcomputed tomography for improved anatomical comprehension. Anat Rec. 2014;297(10):1808–16.
Details
| Primary Language | English |
|---|---|
| Subjects | Health Services and Systems (Other) |
| Journal Section | Articles |
| Authors | |
| Publication Date | June 17, 2025 |
| Submission Date | November 6, 2024 |
| Acceptance Date | May 15, 2025 |
| Published in Issue | Year 2025 Volume: 17 Issue: 2 |
