Evidence map›Paper›PMID 39495299›Full record

Observational studyEuropean archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery2025

Prevalence and characteristics of facial nerve bifurcation in the mastoid segment: a retrospective analysis using temporal bone CT scans.

Masato Suzuki, Ryoukichi Ikeda, Iori Kusaka, Aya Katsura, Jun Suzuki, Kiyoto Shiga

Abstract readObservational Study
PubMed Publisher
In one paragraph

Observational study in European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Radiologic detectability and anatomic course of Arnold's nerve on temporal bone HRCT: A cross-sectional study.European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery · 2026
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Masato SuzukiDepartment of Otolaryngology-Head-Neck Surgery, Iwate Medical University School of Medicine, 2-1-1 Idai dori, Yahaba, Iwate, 028-3695, Japan.
Ryoukichi IkedaDepartment of Otolaryngology-Head-Neck Surgery, Iwate Medical University School of Medicine, 2-1-1 Idai dori, Yahaba, Iwate, 028-3695, Japan. ryoukich@hotmail.com.ORCID http://orcid.org/0000-0003-0076-6092
Iori KusakaDepartment of Otolaryngology-Head-Neck Surgery, Iwate Medical University School of Medicine, 2-1-1 Idai dori, Yahaba, Iwate, 028-3695, Japan.
Aya KatsuraDepartment of Otolaryngology-Head-Neck Surgery, Iwate Medical University School of Medicine, 2-1-1 Idai dori, Yahaba, Iwate, 028-3695, Japan.
Jun SuzukiDepartment of Otolaryngology-Head and Neck Surgery, Tohoku University Hospital, Sendai, Japan.
Kiyoto ShigaDepartment of Otolaryngology-Head-Neck Surgery, Iwate Medical University School of Medicine, 2-1-1 Idai dori, Yahaba, Iwate, 028-3695, Japan.

Funding

Japan Society for the Promotion of Science London 23K08993
6 · The paper itself

Abstract

purposeTo investigate the prevalence and characteristics of bifurcation of the facial nerve (FN) in the mastoid segment using temporal bone CT scans.

methodsA total of 970 cases (1931 ears) of temporal bone CT scans were reviewed, including 463 females and 498 males, aged 1 to 95 years (interquartile range: 20-69 years). CT imaging with multiplanar reconstruction (MPR) was used to identify and evaluate the bifurcation of the FN. Cases showing branching were confirmed by consensus among three physicians.

resultsWe identified 10 cases (10 ears) with facial nerve branching in the vertical segment, yielding an incidence rate of 0.52% (10/1931 ears). Every cases were unilateral, predominantly on the left side. Age analysis revealed 1 case (0.22%) in individuals under 20 years and 9 cases (0.61%) in those over 20 years. Bifurcation generally occurred near the middle to lower vertical segment, with the closest proximity to the second genu observed in a 15-year-old patient.

conclusionsBifurcation of the FN in the mastoid segment, though rare, can be encountered in otologic surgery. Detailed preoperative imaging evaluations are crucial for surgical planning to minimize the risk of nerve damage. Our findings emphasize the importance of recognizing anatomical variations in the FN for improving surgical outcomes and patient safety.

Indexed as

Facial NerveMastoidTomography, X-Ray ComputedAdolescentAdultAgedAged, 80 and overAge DistributionBiological Variation, IndividualChildChild, PreschoolFemaleHumansIncidenceInfantMaleElectroneurographyFacial nerve palsyFacial nerve pathwayHouse-Brackmann gradeMiddle ear surgery

Identifiers

PMID39495299

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.