Evidence map›Paper›PMID 42298237›Full record

SynthesisLangenbeck's archives of surgery2026

Surgical anatomy of the recurrent laryngeal nerve: a systematic review and meta-analysis of variants.

Properzi Luca, Vipul D Yagnik, Matteucci Matteo, Filippo Sabatini, Bruno Cirillo, Antonio Pesce, Francesco Brucchi, Sara Luricella, Gianlorenzo Dionigi, Vito D'Adrea and 3 more

Abstract readSystematic ReviewMeta-Analysis
In one paragraph

Synthesis in Langenbeck's archives of surgery, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing 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

0 citing papers in PubMed.

No citing paper in PubMed yet.

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

13 authors.

Properzi LucaDipartimento di Chirurgia Generale e Digestiva, Università degli Studi di Perugia, Ospedale "Santa Maria", Terni, Terni, Italy. luca.properzi@yahoo.it.
Vipul D YagnikDepartment of Surgery, Banas Medical College and Research Institute, Palanpur, Gujarat, India.ORCID http://orcid.org/0000-0003-4008-6040
Matteucci MatteoDepartment of Medicine and Surgery, University of Milan, Milan, Italy.
Filippo SabatiniDipartimento di Chirurgia Generale e Digestiva, Università degli Studi di Perugia, Ospedale "Santa Maria", Terni, Terni, Italy.
Bruno CirilloDepartment of Surgery, Sapienza University, Viale del Policlinico 155, Rome, 00161, Italy.
Antonio PesceDepartment of Surgery, Azienda Unità Sanitaria Locale Ferrara, University of Ferrara, Lagosanto, FE, Italy.
Francesco BrucchiUniversity of Milan, Milan, 20122, Italy.
Sara LuricellaColorectal Surgery Division, Department of Surgery, Fondazione IRCCS Istituto Nazionale Dei Tumori, Milan, 20133, Italy.
Gianlorenzo DionigiDivision of Surgery, Istituto Auxologico Italiano IRCCS (Istituto Di Ricovero E Cura a Carattere Scientifico), Via Giuseppe Mercalli, 30, Milan, 20122, Italy.
Vito D'AdreaDepartment of Surgery, Sapienza University of Rome, Rome, Italy.
Marco ArticoDepartment of SensoryOrgans, Sapienza University, Rome, 00161, Italy.
Flavio ForteUrology Department of M.G, Vannini Hospital and Science Department of Roma Tre University, Rome, Italy.
Roberto CirocchiDipartimento di Chirurgia Generale e Digestiva, Università degli Studi di Perugia, Ospedale "Santa Maria", Terni, Terni, Italy.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundInjury to the recurrent laryngeal nerve (RLN) remains a significant concern in thyroid surgery. The inferior thyroid artery (ITA) is frequently used as a landmark. Yet, the RLN-ITA relationship shows substantial anatomical variability, and the non-recurrent laryngeal nerve (NRLN) represents a rare but high-risk variant. This systematic review and meta-analysis quantified the prevalence of RLN-ITA topographic patterns and NRLN occurrence. MATERIALS AND

methodsA PRISMA-compliant search was performed across major databases up to May 1, 2025. Eligible studies included intraoperative, cadaveric, or mixed anatomical series reporting extractable numerical data on RLN-ITA relationships (anterior, posterior, interposed) and/or NRLN prevalence, using the hemisoma as the unit of analysis. Study quality was assessed with the AQUA tool. Proportions were pooled using Freeman-Tukey double arcsine transformation under a random-effects model with REML estimation. Heterogeneity was quantified with I², τ², and Cochran's Q, and prespecified subgroup analyses were conducted by study setting.

resultsSixty studies (1973-2025) comprising 9,032 patients and 14,820 hemisomas were included. Fifty-seven studies contributed 14,169 hemisomas to the RLN-ITA synthesis. Crude proportions were posterior 54.43% (7,712/14,169), anterior 27.11% (3,841/14,169), and interposed 18.46% (2,616/14,169). Random-effects pooling confirmed a posterior course as the most frequent configuration (~ 52%, 95% CI ~ 46-58%), followed by anterior (~ 30%, 95% CI ~ 24-36%) and interposed (~ 18%, 95% CI ~ 15-21%), with very high heterogeneity (I² > 97%). Subgroup analyses of intraoperative (30 studies; 10,376 hemisomas) and cadaveric (25 studies; 3,589 hemisomas) series yielded similar distributions, with persistently high heterogeneity (I² > 94%). Across all studies, 39 NRLNs were identified, all on the right side, corresponding to a prevalence of 0.78% among right hemisomas (n = 4,974); no left-sided NRLNs were reported.

conclusionThe RLN most commonly courses posterior to the ITA, but anterior and interposed variants are sufficiently frequent to mandate systematic intraoperative verification before vessel ligation. The NRLN is rare and exclusively right-sided in available data, yet clinically significant due to its high injury risk. Marked between-study heterogeneity highlights the need for standardized definitions and side-specific reporting in future anatomical research.

Indexed as

Anatomic VariationRecurrent Laryngeal NerveRecurrent Laryngeal Nerve InjuriesThyroidectomyThyroid GlandHumansInferior thyroid arteryNon-recurrent laryngeal nerveRecurrent laryngeal nerve

Identifiers

PMID42298237
PMCPMC13582130

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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.