Postnatal Morphometric Development and Variability of the Posterior Canaliculus: An Analysis in a Japanese Population Using Photon-Counting Detector Computed Tomography

Postnatal Morphometric Development and Variability of the Posterior Canaliculus: An Analysis in a Japanese Population Using Photon-Counting Detector Computed Tomography | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Postnatal Morphometric Development and Variability of the Posterior Canaliculus: An Analysis in a Japanese Population Using Photon-Counting Detector Computed Tomography Hiroshi Sakaida, Yasutaka Ichikawa, Akio Yamazaki, Hajime Sakuma This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7391399/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 06 Oct, 2025 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted 9 You are reading this latest preprint version Abstract Objective The posterior canaliculus (PC) is a critical landmark in otologic surgery, but a quantitative in vivo characterization of its postnatal development is lacking. This study aimed to utilize the ultra-high spatial resolution of photon-counting detector computed tomography (PCD-CT) to conduct a definitive in vivo morphometric analysis of the PC's length and its spatial relationship to the facial nerve (FN) across a wide age range in a Japanese population, characterizing its developmental trajectory and variability. Methods This retrospective, cross-sectional study analyzed temporal bone PCD-CT scans from 128 consecutive Japanese patients (265 sides), aged 0 to 59 years. Using multiplanar reconstructions, the length of the PC and the distance between the PC and the mastoid segment of the FN (PC-FN distance) at the level of the tympanic entry were measured. The relationships between these parameters and age were analyzed using locally estimated scatterplot smoothing (LOESS). Results The mean PC length was 8.31 ± 2.50 mm (range: 2.59–14.58 mm), and the mean PC-FN distance was 2.80 ± 0.74 mm (range: 1.01–6.18 mm). LOESS analysis revealed a distinct developmental trajectory: PC length increased progressively from birth, plateauing around age 20, with the most rapid growth occurring in the first year of life. Conversely, the PC-FN distance decreased from birth, stabilizing around age 9. Both parameters exhibited significant inter-individual variability, particularly in the pediatric cohort. Notably, the PC was unidentifiable in 14 temporal bones, all from patients under 10 years old (mean age: 2.3 years). Conclusion This study provides the first in vivo quantitative evidence of the PC's postnatal morphogenesis, demonstrating significant elongation and a concurrent narrowing of the facial recess during childhood. This dynamic anatomical development, coupled with high individual variability, defines a "high-risk window" in pediatric otologic surgery. The findings underscore the necessity of preoperative high-resolution imaging for patient-specific surgical planning and highlight the transformative capability of PCD-CT in micro-anatomical research. posterior canaliculus chorda tympani nerve facial nerve photon-counting detector computed tomography Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 06 Oct, 2025 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted Editorial decision: Revision requested 05 Sep, 2025 Reviews received at journal 27 Aug, 2025 Reviewers agreed at journal 25 Aug, 2025 Reviewers agreed at journal 23 Aug, 2025 Reviewers agreed at journal 18 Aug, 2025 Reviewers invited by journal 18 Aug, 2025 Editor assigned by journal 18 Aug, 2025 Submission checks completed at journal 18 Aug, 2025 First submitted to journal 17 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7391399","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":505127693,"identity":"c5fe90e3-1d9d-4bf3-9a98-589db3ae92b8","order_by":0,"name":"Hiroshi Sakaida","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAklEQVRIiWNgGAWjYBACAwYGZiDJzMAP5EiAEQSwEdYi2UCaFiA2OICkHi8w5z/82OBHgbW88bXDB28w5ljIMUgkMH74wcCXh0uL5Yw048Qeg3TDbbfTki0Yt0kYA7UwS/YwsBXjdNgNBuMDPAaHGbfdzjGTAGpJ3H8jgUEa6JfEBlxazh//fPCPwWH7zbPzv4G01DcAbfmNV8uBHONkoC2JG6Rz2EBaEoAOY8Nvy42cYmMZg/TkGbfTjC0St0kYNvA8bLPsMcDjl/PHN0u++WNt2z87+eGNj9vq5BnYkw/f+FFxDGeIoYIEMMkIdJLBsQTitCCBGtK1jIJRMApGwXAFAPPDUB6CCJ8nAAAAAElFTkSuQmCC","orcid":"","institution":"Mie University","correspondingAuthor":true,"prefix":"","firstName":"Hiroshi","middleName":"","lastName":"Sakaida","suffix":""},{"id":505127694,"identity":"40d36175-aeab-41cf-94ac-4418022e07c5","order_by":1,"name":"Yasutaka Ichikawa","email":"","orcid":"","institution":"Mie University","correspondingAuthor":false,"prefix":"","firstName":"Yasutaka","middleName":"","lastName":"Ichikawa","suffix":""},{"id":505127695,"identity":"d4e8c7c7-062e-471c-a4d2-bc1c0ce7b6d9","order_by":2,"name":"Akio Yamazaki","email":"","orcid":"","institution":"Mie University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Akio","middleName":"","lastName":"Yamazaki","suffix":""},{"id":505127696,"identity":"346ac873-eb54-4dd4-bcd9-26efeb039c34","order_by":3,"name":"Hajime Sakuma","email":"","orcid":"","institution":"Mie University","correspondingAuthor":false,"prefix":"","firstName":"Hajime","middleName":"","lastName":"Sakuma","suffix":""}],"badges":[],"createdAt":"2025-08-17 09:08:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7391399/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7391399/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00276-025-03733-6","type":"published","date":"2025-10-06T15:58:04+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":93419775,"identity":"c88604bc-6214-4a49-8674-9fae96176c5b","added_by":"auto","created_at":"2025-10-13 16:07:24","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":795083,"visible":true,"origin":"","legend":"","description":"","filename":"MaintextPCSurgicalandradiolgicanatomy.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7391399/v1_covered_a0843f63-830b-4f93-9ea8-134d27d5d5b5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Postnatal Morphometric Development and Variability of the Posterior Canaliculus: An Analysis in a Japanese Population Using Photon-Counting Detector Computed Tomography","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"posterior canaliculus, chorda tympani nerve, facial nerve, photon-counting detector computed tomography","lastPublishedDoi":"10.21203/rs.3.rs-7391399/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7391399/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e\u003cp\u003eThe posterior canaliculus (PC) is a critical landmark in otologic surgery, but a quantitative in vivo characterization of its postnatal development is lacking. This study aimed to utilize the ultra-high spatial resolution of photon-counting detector computed tomography (PCD-CT) to conduct a definitive in vivo morphometric analysis of the PC's length and its spatial relationship to the facial nerve (FN) across a wide age range in a Japanese population, characterizing its developmental trajectory and variability.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThis retrospective, cross-sectional study analyzed temporal bone PCD-CT scans from 128 consecutive Japanese patients (265 sides), aged 0 to 59 years. Using multiplanar reconstructions, the length of the PC and the distance between the PC and the mastoid segment of the FN (PC-FN distance) at the level of the tympanic entry were measured. The relationships between these parameters and age were analyzed using locally estimated scatterplot smoothing (LOESS).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe mean PC length was 8.31\u0026thinsp;\u0026plusmn;\u0026thinsp;2.50 mm (range: 2.59\u0026ndash;14.58 mm), and the mean PC-FN distance was 2.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74 mm (range: 1.01\u0026ndash;6.18 mm). LOESS analysis revealed a distinct developmental trajectory: PC length increased progressively from birth, plateauing around age 20, with the most rapid growth occurring in the first year of life. Conversely, the PC-FN distance decreased from birth, stabilizing around age 9. Both parameters exhibited significant inter-individual variability, particularly in the pediatric cohort. Notably, the PC was unidentifiable in 14 temporal bones, all from patients under 10 years old (mean age: 2.3 years).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThis study provides the first in vivo quantitative evidence of the PC's postnatal morphogenesis, demonstrating significant elongation and a concurrent narrowing of the facial recess during childhood. This dynamic anatomical development, coupled with high individual variability, defines a \"high-risk window\" in pediatric otologic surgery. The findings underscore the necessity of preoperative high-resolution imaging for patient-specific surgical planning and highlight the transformative capability of PCD-CT in micro-anatomical research.\u003c/p\u003e","manuscriptTitle":"Postnatal Morphometric Development and Variability of the Posterior Canaliculus: An Analysis in a Japanese Population Using Photon-Counting Detector Computed Tomography","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-26 12:45:12","doi":"10.21203/rs.3.rs-7391399/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-05T09:54:24+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-27T07:39:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"220551071397730726637791388923191677989","date":"2025-08-25T08:19:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"332795363277039523756139764610750971023","date":"2025-08-23T20:35:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"137680544672026469048997006488947833126","date":"2025-08-18T16:54:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-18T16:49:38+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-18T13:18:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-18T08:40:43+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surgical and Radiologic Anatomy","date":"2025-08-17T08:52:07+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"1a296215-0510-4e75-9e62-87ce2372f115","owner":[],"postedDate":"August 26th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-10-13T16:02:24+00:00","versionOfRecord":{"articleIdentity":"rs-7391399","link":"https://doi.org/10.1007/s00276-025-03733-6","journal":{"identity":"surgical-and-radiologic-anatomy","isVorOnly":false,"title":"Surgical and Radiologic Anatomy"},"publishedOn":"2025-10-06 15:58:04","publishedOnDateReadable":"October 6th, 2025"},"versionCreatedAt":"2025-08-26 12:45:12","video":"","vorDoi":"10.1007/s00276-025-03733-6","vorDoiUrl":"https://doi.org/10.1007/s00276-025-03733-6","workflowStages":[]},"version":"v1","identity":"rs-7391399","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7391399","identity":"rs-7391399","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}