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

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

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