Frenectomy for ankyloglossia in children under five: a systematic review and meta-analysis on breastfeeding outcomes

Abstract

Background

To systematically evaluate the clinical effectiveness of lingual frenectomy in children under five years of age, specifically regarding its impact on breastfeeding difficulties.

Methods

A systematic review and meta-analysis were conducted following PRISMA guidelines. A comprehensive search of PubMed, Scopus, Web of Science, LILACS/BBO, Cochrane Library, Epistemonikos, and ProQuest identified clinical studies assessing breastfeeding performance before and after frenectomy in children with ankyloglossia. Data extraction and analysis were completed on 24 October 2024, encompassing all available evidence published up to that date. Methodological quality was appraised using an adapted NICE tool for cohort and cross-sectional studies.

Results

From 2,961 records screened, 55 studies were included in the qualitative synthesis, and 6 provided sufficient data for meta-analysis. The pooled analysis indicated that frenectomy improved breastfeeding outcomes (RR 1.42; 95% CI: 1.32, 1.53). However, substantial heterogeneity was observed (I² = 74.8%). Sensitivity analysis excluding one outlier study markedly reduced heterogeneity but yielded a non-significant effect (RR = 0.99; 95% CI: 0.98–1.01), underscoring the impact of methodological variability. Subgroup analysis by sample size showed no significant effect modification. Qualitative assessment revealed notable methodological weaknesses. Selection bias was identified in 33% of studies and detection bias in 93%, primarily due to heterogeneity in diagnostic criteria and outcome measurements. Only 28.6% of studies applied validated diagnostic tools. Diagnostic methods most frequently used were the Coryllos classification (27%) and the Hazelbaker Assessment Tool for Lingual Frenulum Function (19%). Breastfeeding-related outcomes were often assessed through maternal self-reports, including nipple pain (VAS, 33%), LATCH (20%), and IBFAT (13%). These inconsistencies limited comparability across studies.

Conclusions

Lingual frenectomy may enhance breastfeeding outcomes in children under five with ankyloglossia; however, the limited number of eligible studies, heterogeneity, and methodological shortcomings preclude firm clinical recommendations. Ankyloglossia can compromise breastfeeding, a critical factor for infant health and development. While frenectomy represents a potential therapeutic option, standardized diagnostic tools and evidence-based guidelines are needed to optimize patient selection and minimize both over- and under-treatment in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13006-025-00773-x.

Background

Lingual ankyloglossia, commonly known as tongue-tie, has an estimated prevalence ranging from 4% to 16% [1–4]. It results from the persistence of embryonic tissue beneath the tongue [5], which restricts tongue mobility [3, 6]. This anatomical limitation can lead to an imbalance in orofacial muscular forces [7], contributing to functional impairments such as swallowing difficulties [8, 9], craniofacial growth disturbances [9–12], respiratory disorders [8, 9, 13], and obstructive sleep apnea (OSA) [14–16] among others.

In early infancy, ankyloglossia can significantly affect breastfeeding by impairing milk transfer efficiency, reducing maternal milk production [17–19], limiting infant weight gain [19, 20], prolonging feeding sessions [18], and causing maternal breast pain due to ineffective latch [17, 21, 22]. These complications may threaten the continuation of exclusive breastfeeding and increase the risk of undernutrition, particularly in vulnerable populations. In this context, timely diagnosis and treatment of ankyloglossia represent a critical public health measure that may not only prevent long-term developmental complications [23], but also improve breastfeeding rates, reduce undernutrition, and potentially prevent thousands of infant deaths globally [24, 25].

Lingual frenotomy is currently the predominant treatment when lactation or speech-language specialists have not been successful in relieving symptoms [1, 26, 27]. However, the effectiveness of the clinical indications for this procedure remains controversial. Debate persists regarding both the diagnostic criteria for ankyloglossia and the optimal timing of surgical management [28–30]. Notably, the diagnosis of ankyloglossia increased by up to 834% within just a 15-year period (1997–2012) in countries such as the United States, Australia, and Canada [28], a trend that closely parallels the rise in surgical interventions [31, 32]. This increase may be partly explained by the heterogeneous application of diagnostic tools, including the Lingual Frenulum Protocol with Scoring for Infants [33], the Hazelbaker Assessment Tool for Lingual Frenulum Function (HATLFF) [34, 35], the Bristol Tongue Assessment Tool (BTAT) [36], and the Coryllos classification [37], among others.

Several authors have emphasized the need for careful patient selection to identify infants and young children most likely to benefit from frenectomy, thereby minimizing unnecessary surgical interventions [2, 38, 39]. Nevertheless, professional opinions remain sharply divided: only 10% of pediatricians and 30% of otolaryngologists believe that ankyloglossia affects feeding, while 69% of lactation consultants report breastfeeding difficulties attributed to this condition [40].

Given the ongoing lack of consensus [41, 42] and considering the well-established benefits of exclusive breastfeeding during the first six months of life as recommended by the World Health Organization (WHO), there is an urgent need for standardized, evidence-based clinical guidelines to support the timely and effective treatment of lingual ankyloglossia [43]. Therefore, the aim of this study was to systematically evaluate the clinical indications and efficacy of lingual frenectomy in children under five years of age, with a particular focus on its effects on breastfeeding outcomes.

Methods

Protocol and registratio

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The study protocol was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42021284706.

The research question was structured using the P.E.O. framework:

• Population: Children under five years of age.

• Exposure: Lingual frenectomy.

• Outcome: Indications for surgical intervention.

The primary research question was: What are the clinical indications for lingual frenectomy in children under five years of age?

Eligibility criteria

Inclusion criteria

• Clinical studies, including randomized controlled trials (RCTs), prospective or retrospective cohort studies, and cross-sectional studies.

• Studies evaluating lingual frenectomy in healthy children under five years of age, regardless of the surgical approach (e.g., conventional, laser-assisted, or electrosurgery).

• Studies reporting outcomes related to breastfeeding performance before and after frenectomy.

Exclusion criteria

• Studies involving children with special healthcare needs, due to potential anatomical variations that may affect surgical outcomes.

• Studies that did not specify clinical indications for frenectomy or were not available in full-text format.

Search strategy

A comprehensive search was conducted on 24 October 2024, following PRISMA methodology. The following electronic databases were searched: PubMed, Scopus, Web of Science, LILACS/BBO, Cochrane Library, Epistemonikos, and ProQuest. The search strategy included the following controlled vocabulary and keywords: “Frenum lingual” (MeSH), “Ankyloglossia” (DeSH), “Tongue Tie” (DeSH), “Child” (DeSH), and “Pediatric dentist” (see additional file Table 1). Additionally, the reference lists of all included studies were manually screened to identify relevant articles not retrieved by the electronic search. No restrictions were placed on publication year or language.

Table 1.

Randomized clinical trials included. (0 = Newborn)

Author/Year	Study Design	Age (month)	Sample Size	Number of subjects with surgery	Follow up (months)	Data collection	Main findings	Surgical treatment	Anesthesia use/type	Post-surgical indications
Berry 2012 [1]	A Prospective Randomized Trial	0–4	60	27	0–3	Clinical examination and maternal questionnaire	5% Light bleeding	Frenotomy	Without anesthesia	No report
Buryk, 2011 [26]	A Prospective Randomized Trial	0–2	58	31	0–12	Clinical examination and maternal questionnaire		Frenotomy	Anesthesia	No report
Emond, 2013 [3]	A Prospective Randomized Trial	0–3	107	55	0–2	Clinical examination and maternal questionnaire		Frenotomy	No report	No report
Ghaheri, 2022 [44]	A Prospective Randomized Trial	0–4	48	41	0 (20 days)	Clinical examination and maternal questionnaire		Frenotomy	Topical anesthesia lidocaine and tetracaine 3%	Stretching exercises
Hogan 2005 [45]	A Prospective Randomized Trial	0–3.5.5	57	56	0–4	Clinical examination and maternal questionnaire		Frenotomy	Without anesthesia	No report

The research question was deliberately kept broad to capture all clinical reports of lingual frenectomy in children with ankyloglossia, recognizing that breastfeeding is not always explicitly reported as the primary indication in study records. Restricting the initial search to breastfeeding alone could have introduced systematic selection bias. The restriction to breastfeeding-related outcomes was therefore applied during the eligibility phase, as described below.

Study selection

Study selection was conducted in two phases. In Phase 1, two independent reviewers (JZR and GJD) screened titles and abstracts to identify studies meeting the inclusion criteria. Discrepancies were resolved by consensus or by consulting a third reviewer (ILM). Studies with insufficient information in the abstract were advanced to Phase 2.

In Phase 2, full-text versions of the selected studies were independently assessed by three reviewers (JZR, GJD, and ILM) using the predefined inclusion criteria. At this stage, only studies that explicitly reported breastfeeding-related outcomes before and after frenectomy were retained for qualitative and quantitative synthesis. Final inclusion was based on consensus following full-text evaluation, and all details were documented in the extraction master table.

Risk of bias in individual studies

Risk of bias was assessed using the Cochrane RoB2 assessment tool for randomized controlled trials and the National Institute for Health and Care Excellence (NICE) quality tool for cohort studies, adapted for this review. The following domains were assessed:

• Selection bias.

• Performance bias.

• Attrition bias.

• Detection bias.

Each domain was independently rated as having a “low,” “unclear,” or “high” risk of bias by two reviewers (JZR and GJD). Disagreements were resolved through discussion with a third reviewer (ILM).

Statistical analysis

To evaluate the effectiveness of lingual frenectomy for treating ankyloglossia, risk ratios (RRs) were calculated for each eligible study and presented using forest plots. Only studies that reported pre- and post-operative breastfeeding function and clinical signs related to ankyloglossia were included in the quantitative analysis.

Meta-analysis was performed using data from clinical studies comparing lingual frenectomy to no intervention in infants with breastfeeding difficulties associated with ankyloglossia. For each study, a 2 × 2 contingency table was created, capturing the number of infants showing functional breastfeeding recovery with or without surgery. RRs and corresponding 95% confidence intervals (CIs) were computed. When zero events were reported, a continuity correction of 0.5 was applied. Given the clinical and methodological variability across studies, a random-effects model was used to calculate the pooled effect estimate. Heterogeneity was assessed using Cochran’s Q test and the I² statistic.

Results

The initial database search identified 2,961 records, with an additional 3 studies retrieved through manual reference screening. After automated removal of duplicates, 1,329 unique records remained. Title and abstract screening excluded 1,103 articles, and 226 abstracts were reviewed in detail. Following full-text assessment of 83 articles, 28 were excluded for not meeting eligibility criteria. A total of 55 studies were included in the final qualitative synthesis, of which 6 studies met the criteria for inclusion in the meta-analysis (Fig. 1).

Fig. 1.

PRISMA flow diagram outlining the study selection process

The final sample comprised 5 randomized controlled trials (RCTs) (Table 1), 31 prospective cohort studies (Table 2), 16 retrospective cohort studies (Table 3), and 3 cross-sectional studies (Tables 4 and 5).

Table 2.

Cohort studies in children under 2 years of age. (0 = Newborn)

Author/Year	Study Design	Age (month)	Sample Size	Number of subjects with surgery	Follow up (months)	Data collection	Main findings	Surgical treatment	Anesthesia use/type	Post-surgical indications
Amir, 2005 [19]	Prospective cohort	0–3	66	35	3	Clinical examination	No post-surgical complications	Frenotomy	No report	No report
Ballard, 2002 [46]	Prospective cohort	0	127	123	0 (3 days)	Clinical examination and maternal questionnaire	No post-surgical complications	Frenuloplasty	Without anesthesia	No report
Barbera-Perez, 2021 [17]	Prospective cohort	0	36	33	1	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	No report	No report
Billington, 2017 [47]	Prospective cohort	0–3	106	100	3	Clinical examination and maternal questionnaire		Frenotomy	No report	No report
Bundogji, 2020 [47]	Prospective cohort	0–1	323	314	20	Clinical examination and maternal questionnaire		Frenotomy	Without anesthesia	No report
Calloway, 2019 [39]	Prospective cohort	0–2	115	43	0 (14 days)	Clinical examination		Frenotomy	Topical anesthesia	Stretching exercises
Diercks, 2020 [32]	Prospective cohort	1–2	153	46	0 (14 days)	Clinical examination and maternal questionnaire		Frenotomy	Topical anesthesia	Without exercises
Dell’Olio 2022 [48]	Prospective cohort	0	56	56	0–1	Clinical examination and maternal questionnaire	30.4% Pinpoint bleeding during the procedure. 19.6% Carbonization of irradiated tissue	Frenotomy	Topical anesthesia EMLA®	Use Application of hyaluronic acid gel (Aminogam®) after each breastfeeding feeding.
Dixon, 2018 [31]	Prospective cohort	0–2	367	319	6.5	Clinical examination and maternal questionnaire	One case required analgesia One case minor bleeding	Frenotomy	Without anesthesia	Without exercises
Dollberg, 2014 [20]	Prospective cohort	4.5	264	244	6	Clinical examination and maternal questionnaire		Frenotomy	No report	No report
Geddes, 2008 [49]	Prospective cohort	0–3	24	24	0 (7 days)	Clinical examination and maternal questionnaire		Frenotomy	No report	No report
Ghaheri, 2017 [50]	Prospective cohort	3	237	237	0–1	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	Topical anesthesia	Without exercises
Ghagheri, 2018 [51]	Prospective cohort	0–9	54	54	0–6	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	No report	Without exercises
Griffiths, 2004 [52]	Prospective cohort	0–3	215	215	0–3	Clinical examination and maternal questionnaire	1.8% spontaneously resolving ulcers	Frenotomy	Without anesthesia	No report
Haham, 2014 [53]	Prospective cohort	0	200	7	0 (2 weeks)	Clinical examination and maternal questionnaire		Frenotomy	No report	No report
Kumar, 2017 [54]	Retrospective cohort	0–6	134	60	0 (1 week)	Clinical record review	No post-surgical complications	Frenotomy	No report	No report
Lima, 2021 [55]	Prospective cohort	0	50	50	1	Clinical examination	No post-surgical complications	Frenotomy	No report	No report
Lisonek, 2017 [56]	Retrospective cohort	0	40.457	24,975	-	Clinical record review		Frenotomy	No report	No report
Martinelli, 2015 [22]	Prospective cohort	1	109	14	2.5	Clinical examination and maternal questionnaire		Frenotomy	Without anesthesia	No report
Mettias, 2013 [57]	Retrospective cohort	0–1.5.5	63	63	-	Clinical examination and maternal questionnaire	2.8% Light bleeding 2.8% Light ulceration.	Frenotomy	Topical anesthesia lidocaine 2%	No report
Mulldoon, 2017 [58]	Prospective cohort	0–6	281	98	1	Clinical examination and maternal questionnaire		Frenotomy	Without anesthesia or lidocaine topical 5%	None
O’ Callahan, 2013 [59]	Retrospective cohort	0–1.5.5	311	299	5	Clinical examination and maternal questionnaire	Rare cases of bleeding managed with silver nitrate	Frenotomy	Topical anesthesia benzocaine 20%.	No report
Pastor-Vera, 2016 [60]	Prospective cohort	0–6	61	36	0 (15 days)	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	Without anesthesia	No report
Praborini, 2015 [61]	Retrospective cohort	0–6	31	31	0 (3 days, 1 week and weekly	Clinical examination	No major surgical complications Minor bleeding	Frenotomy	Without anesthesia	No report
Prasnky, 2015 [62]	Retrospective cohort	0	618	491	0 (1 week)	Clinical record review	No post-surgical complications	Frenotomy	No report	Stretching exercises
Ramoser,2019 [63]	Retrospective cohort	0–12	295	295	1–1.5	Clinical examination and maternal questionnaire		Frenotomy	Topical anesthesia xylocaine 2%.	No report
Rasteniene, 2021 [64]	Prospective cohort	0–3	50	37	1	Clinical examination and maternal questionnaire	16% Light pain 4% Scar adhesion managed with stretching.	Frenotomy	Topical anesthesia	Stretching exercises
Ridgers 2009 [65]	Prospective cohort	0–3	220	220	0 (2 days and 2 weeks)	Clinical examination and maternal questionnaire	1.8% Light bleeding	Frenotomy	Without anesthesia	No report
Slagther, 2020 [66]	Prospective cohort	0–3	175	175	6	Clinical examination and maternal questionnaire		Frenotomy	Topical anesthesia xylocaine 5%.	Stretching exercises
Schlatter, 2019 [66]	Prospective cohort	0	776	30	0 (2.5 week)	Clinical examination and maternal questionnaire	10% Light bleeding, controlled with local pressure	Frenulotomy	Without anesthesia	No report
Sharma, 2015 [67]	Prospective cohort	0–6	54	36	1	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	Without anesthesia	No report
Srinivasan, 2006 [68]	Prospective cohort	0–3	27	27	3	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	Without anesthesia	No report
Srinivasan, 2019 [69]	Prospective cohort	0–3	30	30	0 (2,7 y 14 days)	Clinical examination and maternal questionnaire		Frenotomy	Without anesthesia	Stretching exercises
Steehler, 2012 [70]	Retrospective cohort	0	367	302	3–60	Clinical record review	2.6% restrictive scars	Frenotomy	Topical anesthesia lidocaine	No report
Sethi, 2013 [38]	Prospective cohort	0–4	85	85	5	Clinical examination and maternal questionnaire		Frenotomy	Without anesthesia	No report
Wen, 2022 [71]	Prospective cohort	0–4	41	41	0–1	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	Topical anesthesia mixture of lidocaine 1% and oxymetazoline.	No report
Wakhanrittee J, 2016 [72]	Prospective cohort	0	328	328	0–3	Clinical examination and maternal questionnaire		Frenulotomy	Topical anesthesia lidocaine 2%	No report
Wongwattana, 2021 [73]	Retrospective cohort	0	526	526	2,4,6 and 12	Clinical record review		Frenotomy	Topical anesthesia lidocaine 2%	No report

Table 3.

Cohort studies in children over 2 years old. (0 = Newborn)

Author/Year	Study Design	Age (month)	Sample Size	Number of subjects with surgery	Follow up (months)	Data collection	Main findings	Surgical treatment	Anesthesia use/type	Post-surgical indications
Ata, 2019 [18]	Retrospective cohort	1–114	382	382	-	Clinical record review	19.9% Hemorrhage controlled by suturing or cauterization	Frenotomy	Without anesthesia	No report
Bawazir, 2021 [74]	Retrospective cohort	31	118	118	12	Clinical examination and maternal questionnaire	Light bleeding controlled with silver nitrate	Frenotomy	Topical anesthesia xylocaine spray General anesthesia in patients older than 4 months	No report
Buck, 2020 [75]	Retrospective cohort	12–192	226	226	-	Clinical record review		Frenectomy	General anesthesia	No report
Chi-oi, 2020 [76]	Prospective cohort	0–29	49	36	4	Maternal questionnaire		Frenotomy	Without anesthesia	No report
Heler, 2005 [77]	Retrospective cohort	36–108	16	16	10	Clinical examination	No post-surgical complications	Frenuloplasty	General anesthesia	Stretching exercises
Klockars, 2009 [78]	Retrospective cohort	0–216	317	317	-	Clinical record review and maternal questionnaire		Frenoplasty or Frenuloplasty.	General anesthesia in frenoplasty With or without local anesthesia frenotomy.	No report
Marchesan, 2012 [79]	Prospective cohort	24–396	53	10	1	Clinical examination		Frenectomy	No report	No report
Nabeyama, 1985 [80]	Retrospective cohort	0–168	123	78	-	Clinical record review		-	General anesthesia Local anesthesia	No report
Naimer, 2003 [81]	Retrospective cohort	4–144	13	13	-	Clinical examination	No post-surgical complications	-	Local anesthesia Mepivacaine 1%;	No report

Table 4.

Cross sectional studies in children under 2 years of age. (0 = Newborn)

Author/Year	Study Design	Age (month)	Sample Size	Number of subjects with surgery	Data collection	Main findings	Surgical treatment	Anesthesia use/type	Post-surgical indications
Ferres-Amat, 2016 [82]	Cross Sectional	0–6	171	88	Clinical examination and maternal questionnaire	No post-surgical complications	Frenotomy	No report	No report
Hong, 2010 [83]	Cross Sectional	0–6	341	341	Clinical examination and maternal questionnaire	Minor complication of bleeding controlled with compression.	Frenotomy	Topical anesthesia benzocaine 20%.	No report

Table 5.

Cross sectional studies in children over 2 years old. (0 = Newborn)

Author/Year	Study Design	Age (month)	Sample Size	Number of subjects with surgery	Data collection	Main findings	Surgical treatment	Anesthesia use/type	Post-surgical indications
Ellehauge, 2020 [84]	Cross Sectional	0–38	3625	3625	Clinical record review	-	Frenotomy	No report	No report

Qualitative analysis

Risk of bias

Risk of bias assessment revealed that up to 40% of RCTs exhibited moderate to high risk in at least two key methodological domains, over 60% of cohort studies demonstrated similar concerns, and more than 72% of cross-sectional studies were also at risk (Fig. 2). Overall, selection bias was identified in 33% of studies, while detection bias was present in 93%, primarily due to variability in diagnostic criteria and outcome assessment methods.

Fig. 2.

Risk of bias summary for randomized controlled trials, cohort and cross-sectional studies included in the review

Diagnostic methods

A wide range of diagnostic criteria and assessment tools were used across studies (Fig. 3), including both anatomical classifications and combined anatomy-functional protocols. The most frequently applied system was the Coryllos classification (27%), followed by the Hazelbaker Assessment Tool for Lingual Frenulum Function (ATLFF) (19%). Notably, only 28.6% of studies applied validated diagnostic instruments [3, 36, 85].

Fig. 3.

Diagnostic tools and classification systems employed to identify ankyloglossia

In addition, several studies assessed breastfeeding-related symptoms through maternal self-report instruments, most commonly the Visual Analog Scale (VAS) for nipple pain (33%), the LATCH scoring system (20%), and the Infant Breastfeeding Assessment Tool (IBFAT) (13%) (Fig. 4).

Fig. 4.

Scales and questionnaires used to assess breastfeeding symptoms in infants with ankyloglossia

Meta-analysis

The pooled analysis of the 6 eligible studies (Table 6) yielded a risk ratio (RR) of 1.42 (95% CI: 1.32, 1.53), suggesting that frenectomy may improve breastfeeding outcomes compared with no surgical intervention (Fig. 5). However, substantial heterogeneity was observed (I² = 74.8%, Q = 19.87, p = 0.0013), indicating notable variability in study designs, diagnostic tools, and measured outcomes. A sensitivity analysis excluding the outlier study by Ballard et al. [46] markedly reduced heterogeneity but produced a non-significant effect estimate (RR 0.99, 95% CI: 0.98, 1.01; p = 0.3633) (Fig. 5B). This finding highlights the influence of individual studies on the overall pooled effect and underscores the need for cautious interpretation.

Table 6.

Summary of studies included in the meta-analysis, reporting at least two outcome parameters related to pre- and post-operative breastfeeding function and diagnosis of ankyloglossia

Study	N (Total Subjects)	Frenectomy Perform	No Frenectomy Performed	Cases (Function Recover Post Frenectomy)	Recover Function Whit-Out Frenectomy
Chi -Oi, 2020 [76]	42	36	6	29	4
Ballard, 2002 [46]	127	123	123	123	0
Ferres-Amat, 2016 [82]	171	88	83	73	77
Kumar, 2017 [54]	125	60	65	60	65
Pastor-Vera, 2016 [60]	61	36	25	29	19
Hong, 2010 [83]	341	273	68	273	68

Fig. 5.

Forest plot of the effectiveness of frenectomy for improving breastfeeding outcomes in infants with ankyloglossia. The plot A displays the individual risk ratios (RRs) and 95% confidence intervals (CIs) from six clinical studies comparing frenectomy versus no intervention. Squares represent the RR from each study, with sizes proportional to the inverse variance (study weight). Horizontal lines denote the 95% CI. The vertical dashed line indicates the null effect (RR 1). The red diamond at the bottom summarizes the pooled effect estimate using a random-effects model (RR 1.42, 95% CI: 1.32, 1.53), which does not include the null value, indicating statistical significance (p = 0.0015). The plot B displays the effect estimate with-out extreme values from studies with high heterogenicity (Ballard et al. [46]), showing no statistical significance (p = 0.3633)

Although 55 studies were eligible, only 6 provided sufficient and comparable quantitative data to be included in the meta-analysis. Most excluded studies (n = 46) did not report pre- and post-intervention measurements of breastfeeding function with the same diagnostic tools, relying instead on maternal self-reports, which limited comparability. An additional 3 studies were excluded due to incomplete or missing post-intervention data, despite attempts to contact corresponding authors for clarification. Consequently, only 6 studies with extractable and comparable data were retained for quantitative synthesis, despite some having unbalanced intervention and control groups.

Subgroup and bias analyses.

Subgroup analysis based on sample size (≤ 100 vs. > 100 participants) did not demonstrate a significant difference (Fig. 6) between groups (Q = 0.44, df = 1, p = 0.5065). Smaller studies (k = 2) yielded a non-significant trend favoring frenectomy (RR 1.08, 95% CI: 0.85, 1.39), while larger studies (k = 3) produced a null effect (RR 0.99, 95% CI: 0.98, 1.01). These results should be interpreted cautiously, given the limited number of studies in each subgroup.

Fig. 6.

The plot A displays the subgroup analysis from the as “Small” (n ≤ 100) and “Large” (n >100) studies. Overall Effect: Pooled RR 0.98 (95% CI: 0.91–1.05), indicating no significant benefit of frenectomy over no frenectomy. Study-Specific Findings: Only Chi -Oi [76] suggests a non-significant trend favoring frenectomy (RR 1.21). Ferres-Amat [86] shows a non-significant trend favoring no frenectomy (RR 0.89). Heterogeneity: Low (I² = 15%), supporting the use of a fixed-effects model. The funnel plot in B showed symmetrical distribution of the studies, with-out small-study effects

Publication bias was assessed through contour-enhanced funnel plots and the trim-and-fill method. The distribution appeared symmetrical, and no additional studies were imputed. The adjusted summary estimate (RR 0.998, 95% CI: 0.981, 1.015) was unchanged, and Egger’s test showed no significant asymmetry (p = 0.610). These findings suggest no evidence of small-study effects or selective reporting; however, the limited number of trials reduces the interpretive power of these tests.

Discussion

This systematic review revealed considerable methodological variability in the diagnosis and evaluation of ankyloglossia. Among the 55 included studies, 93% demonstrated detection bias and 33% showed selection bias (Fig. 2), particularly among cohort and cross-sectional designs. These findings underscore the urgent need for standardized diagnostic and assessment protocols to enhance reliability and reproducibility in this field.

Quantitatively, the evidence base included five randomized controlled trials (RCTs), 31 prospective cohort studies, 16 retrospective cohort studies, and three cross-sectional studies (Tables 1, 2, 3, 4 and 5). Up to 40% of the RCTs exhibited moderate to high risk of bias in at least two key methodological domains. Detection bias was identified in 62% of cohort studies and in 100% of cross-sectional studies (Fig. 2). These results highlight the lack of methodological rigor, particularly regarding the standardization of outcome measures related to the efficacy of interventions for ankyloglossia.

Despite the recognized clinical relevance of ankyloglossia [87, 88], there remains no consensus on the clinical indications for frenectomy [89]. While institutions such as the American Academy of Pediatric Dentistry and the UK’s NICE guidelines acknowledge that a restrictive lingual frenulum may impact child health [90–92]—a position supported by several authors [20, 45, 70]—the Canadian and Japanese Pediatric Societies contend that tongue-tie generally does not interfere with breastfeeding and therefore do not support routine frenotomy [93, 94]. This divergence in professional guidelines reflects the diagnostic heterogeneity observed across the reviewed studies (Fig. 5), which employed varied tools such as the Lingual Frenulum Protocol with Scoring for Infants, the Hazelbaker Assessment Tool for Lingual Frenulum Function (ATLFF), the Bristol Tongue Assessment Tool (BTAT), and the Coryllos classification. Such heterogeneity impedes the establishment of standardized care and is consistent with findings from prior reviews [95, 96].

The primary meta-analysis demonstrated a statistically significant pooled effect (RR 1.42; 95% CI: 1.32, 1.53), suggesting that frenectomy may improve breastfeeding outcomes. However, substantial heterogeneity (I² = 74.8%) reduced the certainty of this conclusion. Sensitivity analysis excluding the study by Ballard et al. [46], which had extreme values, markedly lowered heterogeneity but yielded a non-significant result (RR 0.99; 95% CI: 0.98, 1.01). This indicates that the observed benefit is not consistent across studies and emphasizes the influence of methodological variability on effect estimates, in line with Cochrane recommendations.

A key limitation of the present meta-analysis was that, despite identifying 55 eligible studies, only 6 could be included in the quantitative synthesis. Most excluded studies lacked objective and comparable pre- and post-intervention measurements of breastfeeding function, instead relying primarily on maternal self-reports. While patient-reported outcomes are valuable, they did not permit calculation of standardized effect sizes. Additional exclusions were due to missing or incomplete post-intervention data, even after attempts to contact corresponding authors. Moreover, the included studies often presented unbalanced intervention and control groups, which complicates interpretation. These limitations highlight the urgent need to standardize outcome reporting in clinical trials on lingual frenectomy, ideally following guidelines such as CONSORT. Strengthening methodological rigor will improve comparability across studies and ultimately generate more robust evidence to guide clinical decision-making in this field.

The subgroup analysis based on total sample size revealed no statistically significant difference between small (n ≤ 100) and large (n > 100) studies. While smaller studies showed a modest, non-significant trend favoring frenectomy, larger studies yielded a null effect. Clinically, this discrepancy indicates that the apparent benefit observed in small, underpowered trials should be interpreted with caution, as it may reflect random variation or publication bias. In practice, the evidence from larger studies—which carry greater methodological weight—suggests that the benefit of frenectomy for breastfeeding outcomes remains uncertain. These findings reinforce the need for adequately powered RCTs with standardized outcome measures before making strong clinical recommendations.

Assessment of publication bias through funnel plot visualization and the trim-and-fill method did not reveal evidence of small-study effects or missing studies. The adjusted summary estimate remained identical to the original, and Egger’s test did not identify statistically significant asymmetry. Taken together, these results increase confidence in the robustness of the primary effect estimate. Nonetheless, caution is warranted, as secondary analyses have reduced reliability when fewer than ten studies are available [97].

The clinical implications are substantial. While ankyloglossia may compromise breastfeeding, the lack of consistent diagnostic and treatment thresholds undermines optimal care delivery [41]. A coordinated, multidisciplinary approach is required to establish and implement standardized, evidence-based protocols [98], which would advance both clinical decision-making and future research. With a prevalence estimated between 4% and 16% [1, 3, 4], ankyloglossia represents a highly relevant condition in the context of breastfeeding [4]. The lingual frenulum is not an isolated cord of tissue but rather a fascial fold of the floor of the mouth, whose basket-weave arrangement generates tension and dynamic restriction of movement during tongue elevation [99], which impairs milk transfer and causes maternal nipple pain due to poor latch [68]. These outcomes align with World Health Organization (WHO) recommendations, which emphasize exclusive breastfeeding for the first six months and continued breastfeeding for up to two years or beyond [43]. Consequently, any condition that compromises breastfeeding continuity should be considered a public health concern [100], and timely, standardized interventions—such as frenotomy—are essential [33, 34, 41].

Several surgical techniques have been proposed, although no single method has demonstrated clear superiority in infants or young children [18]. Clinical evaluation should be individualized. The most common procedures include frenotomy, frenectomy, and frenuloplasty [92, 99, 101]. Among studies involving children under two years of age, frenotomy was the preferred technique in 80% of cases (Tables 1 and 2, and 4), likely due to its minimally invasive nature and short procedural duration [17]. The procedure typically consists of a 2–3 mm incision or excision of the frenulum, most often performed with scissors, which generally results in minimal bleeding and rapid return to feeding. Nevertheless, other approaches such as electrocautery or laser have also been reported in the literature, and these highlight that the frenulum is located in a vascularized and innervated area where careful technique is important [19, 86, 100].

Analgesia protocols were inconsistently reported. A total of 41% of studies did not specify the use of any anesthesia, 33% reported only topical agents, and 5% described the use of local anesthesia. This inconsistency raises concerns regarding procedural pain, particularly in neonates, where cortical processing of nociceptive stimuli has been documented [86, 102–104]. While some authors argue that the short duration of frenotomy justifies omission of anesthesia [105], adequate analgesia is ethically and clinically necessary [106], especially given the anatomical and developmental sensitivity of this population [99]. The absence of standardized surgical protocols (Tables 1, 2, 3, 4 and 5) likely contributes to the variability in anesthetic practices.

Postoperative care also varied considerably. In 80% of the studies, no postoperative instructions were provided [1, 17–20, 22, 26, 36, 38, 45–49, 52–61, 63, 65–67, 70–76, 78–83, 98, 106, 107]. Conversely, 13% recommended stretching exercises at the surgical site [39, 62, 64, 69, 77, 84, 108], while 7% explicitly advised against any manipulation [31, 33, 50, 51]. Although no consensus has been reached [88, 109], some evidence suggests that postoperative massage may reduce adhesion formation and recurrence [109, 110]. The use of topical hyaluronic acid gel has also been proposed to enhance wound healing [48].

Follow-up protocols were rarely standardized. While some studies recommended early follow-up at 24–48 h postoperatively [26, 62], this timeframe may be insufficient to assess sustained breastfeeding success—the primary outcome of early frenotomy. Ideally, follow-up should occur at 7–14 days to monitor wound contraction [111], with additional evaluations at 1 month [22, 67], 3 months [112], and 6 months [20] to assess long-term outcomes and support the breastfeeding mother–infant dyad.

Future research should prioritize methodological rigor, including the use of standardized diagnostic criteria, unified surgical protocols, validated outcome measures, and extended follow-up periods to more accurately evaluate the efficacy, safety, and sustainability of lingual frenotomy across diverse pediatric populations.

Conclusion

Although the meta-analysis suggested a statistically significant benefit of lingual frenectomy over no intervention in improving breastfeeding outcomes, the small number of eligible studies and the substantial heterogeneity in diagnostic criteria, study design, and outcome measures prevent drawing definitive conclusions. At present, the available evidence does not support routine frenectomy in all children under five with ankyloglossia.

Lingual frenectomy may offer benefits for selected cases with documented breastfeeding difficulties; however, the absence of standardized diagnostic protocols and the variability in clinical practice underscore the need for cautious, individualized decision-making. These findings highlight the importance of developing evidence-based guidelines to support timely and appropriate treatment that prioritizes both infant health and family well-being.

Future research should address the broader clinical impact of untreated ankyloglossia, including its potential associations with speech development, craniofacial growth, airway function, and sleep-disordered breathing. High-quality, longitudinal studies with standardized diagnostic frameworks and validated outcome measures are essential to clarify these relationships. Ultimately, consensus-driven therapeutic criteria will help ensure that affected infants and young children receive appropriate and proportionate care—guided by the best available evidence and clinical judgment.

Authors’ contributions

[G.J and I.L-M]: Conceptualization, Methodology, Formal analysis, Writing – Original Draft.[J.S and M.M]: Data curation, Visualization, Writing – Review & Editing.[M.M and I.L-M]: Supervision, Validation, Writing – Review & Editing.

Data availability

All data generated or analyzed during this study are included in this published article. Additional details are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

This study did not involve experiments on humans or animals. Ethical approval was not required.

Competing interests

The authors declare no competing interests.