Scope of the Review

This systematic review provides a review of potential benefits of treatments (surgical and nonsurgical) as well as harms associated with those therapies in individuals with ankyloglossia and tight labial frenulum (lip-tie) concomitant with ankyloglossia. We sought information on outcomes related to breast- and bottle-feeding and related to tongue-tie in later life (e.g., orthodontic and dental issues, speech, self-esteem).

Key Questions

We synthesized evidence in the published literature to address the following Key Questions (KQs):

KQ 1. What are the benefits of various treatments in breastfeeding newborns and infants with ankyloglossia intended to improve breastfeeding outcomes? Surgical treatments include frenotomy (anterior and/or posterior), frenuloplasty (transverse to vertical frenuloplasty), laser frenulectomy/frenulotomy, and Z-plasty repair. Nonsurgical treatments include complementary and alternative medicine therapies (e.g., craniosacral therapy), lactation intervention, physical/occupational therapy, oral motor therapy, and stretching exercises/therapy.

KQ 2a. What are the benefits of various treatments in newborns, infants, and children with ankyloglossia intended to prevent, mitigate, or remedy attributable medium- and long-term feeding sequelae, including trouble bottle-feeding, spilling and dribbling, difficulty moving food boluses in the mouth, and deglutition?

KQ 2b. What are the benefits of various treatments in infants and children with ankyloglossia intended to prevent, mitigate, or remedy attributable other medium- and long-term sequelae, including articulation disorders, poor oral hygiene, oral and oropharyngeal dysphagia, sleep disordered breathing, orthodontic issues including malocclusion, open bite due to reverse swallowing, lingual tipping of the lower central incisors, separation of upper central incisors, crowding, narrow palatal arch, and dental caries?

KQ 3. What are the benefits of various treatments for ankyloglossia in children through 18 years of age intended to prevent or address social concerns related to tongue mobility (i.e., speech, oral hygiene, excessive salivation, kissing, spitting while talking, and self-esteem)?

KQ 4. What are the benefits of simultaneously treating ankyloglossia and concomitant tight labial frenulum (lip-tie) in infants and children through age 18 intended to improve or remedy breastfeeding, articulation, orthodontic and dental, and other feeding outcomes? What are the relative benefits of treating only ankyloglossia when tight labial frenulum (lip-tie) is also diagnosed?

KQ 5. What are the harms of treatments for ankyloglossia or ankyloglossia with concomitant lip-tie in neonates, infants, and children through age 18?

Analytic Framework

Figure A depicts KQs 1, 4, and 5 within the context of the PICOTS (population, intervention, comparator, outcomes, timing, setting). The figure examines surgical and nonsurgical treatments in neonates and infants to improve breastfeeding outcomes. Intermediate outcomes include maternal nipple pain, ability to latch and maintain latch, tongue mobility, and aerophagia. Final outcomes include duration of breastfeeding, failure to thrive, infant weight gain, and oral and oropharyngeal dysphagia. Harms (KQ 5) may occur at any point after the intervention is received.

Figure A

Analytic framework for ankyloglossia in neonates and infants.

Figure B depicts KQs 2, 3, 4, and 5 within the context of the PICOTS. The figure examines surgical and nonsurgical treatments in infants and children with ankyloglossia (KQ 2, KQ 3) or ankyloglossia with concomitant lip-tie (KQ 4). The intermediate outcomes include maternal nipple pain and tongue mobility, and final health outcomes are articulation disorder, oral hygiene, oral and oropharyngeal dysphagia, orthodontic problems, psychological outcomes, and social concerns, including kissing. Harms (KQ 5) may occur at any point after the intervention is received.

Figure B

Analytic framework for ankyloglossia in infants and children through18 years of age.

Literature Search Strategy

A librarian employed search strategies provided in Appendix A of the full report to retrieve research on interventions for children with ankyloglossia. We searched MEDLINE^® via the PubMed^® interface, PsycINFO^® (psychology and psychiatry literature), the Cumulative Index of Nursing and Allied Health Literature (CINAHL^®) and Embase (Excerpta Medica Database). We limited searches to the English language and imposed no publication date restrictions. Our last search was conducted in August 2014. We manually searched reference lists of included studies and of recent narrative and systematic reviews and meta-analyses.

Inclusion and Exclusion Criteria

We developed criteria for inclusion and exclusion in consultation with a Technical Expert Panel (Table A).

Table A

Inclusion criteria.

Study Selection

Two reviewers independently assessed each abstract. If one reviewer concluded that the article could be eligible based on the abstract, we retained it for full-text assessment. Two reviewers independently assessed the full text of each included study. Disagreements were resolved by a senior reviewer.

Data Extraction and Synthesis

We extracted data from included studies into an evidence table that reports study design, descriptions of the study populations (for applicability), description of the intervention, and baseline and outcome data on constructs of interest. Data were initially extracted by one team member and reviewed for accuracy by a second. The final evidence table is presented in Appendix D of the full report.

We extracted outcomes for all included studies, and data are presented in summary tables and analyzed qualitatively in the text.

Quality (Risk-of-Bias) Assessment of Individual Studies

We used four tools to assess the quality of individual studies: the Cochrane Risk of Bias Tool for Randomized Controlled Trials;⁶ a cohort study assessment instrument based on questions and a tool for case series, both adapted from RTI Item Bank questions;⁷ and a four-item harms assessment instrument for cohort studies derived from the McMaster Quality Assessment Scale of Harms (McHarm) for Harms Outcomes⁸ and the RTI Item Bank.⁷ The tools are presented in Appendix E of the full report.

Quality assessment of each study was conducted by two team members independently. Discrepancies were adjudicated through discussion between the assessors to reach consensus or via a senior reviewer. The results of these tools were then translated to the Agency for Healthcare Research and Quality standard of “good,” “fair,” and “poor” quality designations, as described in the full report. Quality ratings for each study are in Appendix F of the full report.

Strength of the Body of Evidence

Two senior investigators graded the entire body of evidence using methods based on the “Methods Guide for Effectiveness and Comparative Effectiveness Reviews.”⁹ The team reviewed the final strength-of-evidence designation. Strength of evidence is assessed for a limited set of critical outcomes, typically those related to effectiveness of an intervention, and reported in comparative studies.

The possible grades were—

• High: High confidence that the evidence reflects the true effect. Further research is unlikely to change estimates.
• Moderate: Moderate confidence that the evidence reflects the true effect. Further research may change our confidence in the estimate of effect and may change the estimate.
• Low: Low confidence that the evidence reflects the true effect. Further research is likely to change confidence in the estimate of effect and is also likely to change the estimate.
• Insufficient: Evidence is either unavailable or does not permit a conclusion.

Applicability

Applicability describes issues related to how applicable (generalizable) the included studies are likely to be in practice. We assessed applicability by identifying potential population, intervention, comparator, outcome, and setting (PICOS) factors likely to affect the generalizability of results (i.e., applicability to the general population of children with ankyloglossia). For this particular review, the most likely factors that could affect applicability are the severity/degree of ankyloglossia, age range of participants, setting of intervention (e.g., newborn nursery, outpatient office), and provider (e.g., otolaryngologist, lactation consultant, dentist, pediatrician).

Article Selection

We identified 1,626 nonduplicative titles or abstracts with potential relevance, with 244 proceeding to full-text review (Figure 3 of the full report). We excluded 187 studies at full-text review, which yielded 57 published studies included in the review. We also included one unpublished thesis in our results; thus, the report summarizes data from 58 unique publications.

KQ 1. Benefits of Interventions To Improve Breastfeeding Outcomes

Twenty-nine studies addressed the benefits of surgical treatments intended to improve breastfeeding outcomes; there were no studies of nonsurgical treatments. These studies included five randomized controlled trials (RCTs) conducted in the United Kingdom (n = 3),^10-12 United States (n = 1),¹³ or Israel (n = 1)¹⁴ and one poor-quality retrospective cohort study conducted in the United States.¹⁵ We rated the RCTs as good,^10,11,13 fair,¹² and poor¹⁴ quality for outcomes related to breastfeeding effectiveness and maternal pain related to breastfeeding. One poor-quality retrospective cohort study and 23 case series also addressed outcomes of surgical treatment. We focused on RCTs of higher quality in this summary but noted that the lower quality studies typically reported improvements in breastfeeding effectiveness.

Two RCTs compared frenotomy to sham surgery,^{11, 13} one to usual care,¹⁰ and one to intensive lactation consultation,¹² and one used a crossover design to compare frenotomy followed by sham surgery to sham surgery followed by frenotomy, with assessment of breastfeeding after each order of intervention (i.e., frenotomy and sham).¹⁴ Similarly, the retrospective cohort study compared frenotomy to usual care.¹⁵ For all studies, sham comparison involved taking infants to an intervention room for the same amount of time as the infants receiving the procedure and then returning them to the mothers.

The earliest reported RCT used nonblinded maternally assessed breastfeeding effectiveness and reported that 96 percent of frenotomized infants had improved feeding within 48 hours, compared with 3 percent in the control group, but this study had significant limitations.¹² In a later RCT, mothers again self-reported improved breastfeeding among infants immediately after frenotomy (78% in the treated group vs. 47% in the comparison group; p <0.02).¹¹

Three RCTs used an observer to assess breastfeeding effectiveness. In all three, the observer was blinded to the treatment. Among these,^10,11,13 one reported improvement in breastfeeding effectiveness based on the Infant Breastfeeding Assessment Tool (IBFAT; score range, 0 [poor feeding] to 12 [vigorous and effective feeding]) score immediately postfrenotomy compared with sham treatment (mean, 11.6 ± 0.81 vs. 8.07 ± 0.86; p = 0.026).¹³ In contrast, in two of the three RCTs, the independent blinded observers did not detect a difference in breastfeeding improvement. Outcomes that failed to show a difference in these two RCTs included percent improvement (50% vs. 40%) immediately after intervention¹¹ and Latch, Audible swallowing, Type of nipple, Comfort, Hold (LATCH) and IBFAT change 5 days postintervention: LATCH change score median 1 (interquartile range [IQR], 0 to 2) versus median 1 (IQR, 0 to 2); p = 0.52 and IBFAT change score 0 (IQR, -1.8 to 1.0) versus 0 (IQR 0 to 1); p = 0.36.¹⁰

One RCT reported significant and immediate improvement in maternally reported nipple pain among frenotomized infants compared with sham treatment.¹³ Both remaining RCTs found nonsignificant reductions in maternally reported nipple pain between the frenotomy and sham groups at immediate¹¹ and 5-day¹⁰ postprocedure assessments. However, in the one study that assessed pain at 5 days (the longest followup), a large number of infants in the control group had crossed over to receive frenotomy before outcomes were assessed.¹⁰

Harms were rare and nonsignificant, and are discussed in more detail in KQ 5.

KQ 2a. Benefits of Treatments To Mitigate Feeding Sequelae

Three studies examined medium- and long-term benefits related to feeding outcomes and sequelae of various interventions for infants and children with ankyloglossia.^12,16,17 One was an RCT¹² (fair quality for feeding outcomes) and one was a poor-quality retrospective cohort study;¹⁶ the remaining study was a case series, so it provided no data for comparison.¹⁷

In one RCT that included bottle-fed infants, 76 percent had major problems with dribbling and 71 percent had “excess wind” (gas). Mothers reported significant improvement in bottle-feeding in all eight infants who received the frenotomy and in none of the nine who did not. The interval to ascertainment of the outcomes was not specifically reported, but outcomes were obtained within the first 4 weeks of life.¹²

The retrospective cohort study compared parent-reported (typically maternal) outcomes at age 3 years for three groups of children born in 2010: children who received frenotomy for tongue-tie (n = 71; frenotomy group); those whose parents were offered frenotomy for tongue-tie for their children but declined it (n = 15; no-frenotomy group); and children without ankyloglossia (n = 18; control group).¹⁶ The frenotomy group performed better than the no-frenotomy group at age 3 years on cleaning the teeth with the tongue, licking the outside of the lips, and eating ice cream, and did not differ significantly from the comparison group without ankyloglossia.

KQ 2b. Benefits of Treatments To Prevent Other Sequelae

Two cohort studies attempted to assess the effectiveness of frenotomy for preventing other sequelae,^16,18 and one RCT compared two surgical approaches to frenotomy.¹⁹ A speech- language pathologist measured speech outcomes in two studies,^18,19 with the third study using parental assessment.¹⁶ No studies included data related to sleep disordered breathing, occlusal issues, and dysphagia in nonbreastfeeding children.

Two poor-quality cohort studies^16,18 reported an improvement in articulation and intelligibility with ankyloglossia treatment, but benefits in word and sentence accuracy and intelligibility and fluent speech were unclear. The one poor-quality RCT comparing surgical methods reported improved articulation in patients treated with four-flap Z-frenuloplasty compared with horizontal-to-vertical frenuloplasty.¹⁹ Numerous noncomparative studies^20-26 reported a speech benefit after treating ankyloglossia; however, these studies primarily discussed modalities, with safety, feasibility, or utility as the main outcome rather than speech itself, and they provided no comparative data.

KQ 3. Benefits of Treatments To Prevent Social Concerns Related to Tongue Mobility

Only one poor-quality retrospective cohort study assessed outcomes related to social concerns other than speech in 3-year-old children who had received frenotomy as infants.¹⁶ The group that had received frenotomy had better parent-reported ability to clean teeth with tongue, lick outside of lips, and eat ice cream compared with untreated participants.

KQ 4. Benefits of Simultaneously Treating Ankyloglossia and Lip-Tie

We did not identify any studies addressing this question.

KQ 5. Harms of Treatments for Ankyloglossia or Ankyloglossia With Concomitant Lip-Tie in Neonates, Infants, and Children Through Age 18

In order to identify all possible harms, we sought harms from all comparative studies and case series that we identified as potentially providing effectiveness data, and we sought case reports of harms. With this approach, we examined harms information from 46 studies that reported that they had looked for harms, either reporting actual harms or specifically indicating that they found none. These included 6 RCTs, 1 cohort study, 25 case series, and 15 case reports. Most studies that reported harms information explicitly noted that no significant harms were observed (n = 17) or reported minimal harms. Among studies reporting harms, bleeding was most frequently reported. Bleeding was typically described as minor and limited. Reoperation was noted in seven studies. Few studies described the specific methods they used to collect harms data.

Key Findings

Most of the studies included in this review addressed outcomes related to breastfeeding (Table B). Overall, three good-quality^10,11,13 and one fair-quality¹² RCT assessed whether surgical treatment of ankyloglossia improved breastfeeding effectiveness. Maternally reported breastfeeding effectiveness was significantly improved in the treated group compared with the untreated group in both RCTs that evaluated it either as a primary¹² or secondary¹¹ outcome. Only one of three RCTs that used blinded independent observers found significantly improved breastfeeding effectiveness among frenotomized infants immediately postprocedure.¹³ A third RCT evaluated the mother's breastfeeding self-efficacy and found a significant improvement from baseline in the frenotomy group 5 days postprocedure.¹⁰ In all, some evidence suggests that maternally reported breastfeeding outcomes improved, but data are unavailable to assess the durability of effects.

Table B

Strength of evidence for studies addressing surgical approaches for ankyloglossia.

These same studies had disparate findings about whether frenotomy decreased maternal nipple pain during breastfeeding. Only the RCT performed on infants at 6 days of age showed a significant reduction in maternal pain.¹³ Those performed on infants a few weeks older did not report either an immediate¹¹ or 5-day¹⁰ reduction in pain. The difference between earlier frenotomy and later frenotomy on nipple pain may relate to cumulative trauma on the breast from several additional weeks with inefficient latch from tongue-tied infants.

We identified three studies examining feeding outcomes other than breastfeeding: one RCT,¹² one-poor quality retrospective cohort study,¹⁶ and one case series.¹⁷ Bottle-feeding and ability to use the tongue to eat ice cream and clean the mouth improved more in treatment groups in comparative studies. Bottle feedings to supplement breast feeding decreased over time in the case series.

Following breastfeeding outcomes, outcomes related to speech were most often reported in the ankyloglossia literature. Two poor-quality cohort studies^16,18 reported an improvement in articulation and intelligibility with ankyloglossia treatment, but benefits in word and sentence accuracy and intelligibility and fluent speech were unclear. One poor-quality RCT reported improved articulation in patients treated with Z-frenuloplasty compared with horizontal-to-vertical frenuloplasty.¹⁹ Numerous noncomparative studies reported a speech benefit after treating ankyloglossia; however, these studies primarily discussed modalities, with safety, feasibility, or utility as the main outcome, rather than speech itself.^23,26-28

Few studies addressed social concerns. One retrospective cohort study noted improvements in using the tongue to clean the teeth and for licking in the treatment group compared with untreated participants.¹⁶ In two comparative studies reporting on tongue mobility, mobility improved in treated patients.^18,19

Harms of surgical interventions included minor bleeding, which was typically self-limiting, and need for reoperation, which was rare. Minor bleeding is not an unexpected occurrence in this type of surgical intervention. Eighteen studies reported that no significant harms were observed.

Strength of Evidence

Applicability

Newborns referred for treatment of ankyloglossia were born primarily at tertiary-care centers and recognized as having difficulty with breastfeeding concomitant with ankyloglossia. The frenotomy procedure itself is not technically difficult and is likely performed similarly across birthing sites; however, the criteria by which the decision is made to perform frenotomy are less clear. Moreover, newborns of mothers not choosing to breastfeed may not be recognized as having and/or diagnosed with ankyloglossia, as breastfeeding difficulties were used as an indicator to evaluate for ankyloglossia. At minimum, the studies in this report apply only to infants with both ankyloglossia and feeding difficulties; data on ankyloglossia absent feeding difficulties were unavailable.

In these studies, various clinicians were involved in making the ankyloglossia diagnoses. However, assessment of breastfeeding difficulty and diagnostic criteria for ankyloglossia were not universally described. Lack of a consistent objective measure to define and classify this condition may limit the reproducibility of findings. Furthermore, the age of patients in these studies varied from a median of 6 days of age in one study¹³ up to a mean of 33 days of age (range, 6 to 115) in another study.¹¹ Applicability of findings to older infants cannot be gleaned from these data, nor can durability of results.

Frenotomy was the only intervention employed in the good-quality RCTs.^10,11,13 However, the specifics of the procedure were variably reported. The degree of posterior extension of the frenulum incision was not clearly defined and appears to be at the discretion and clinical expertise of the clinician. Also, the severity of the ankyloglossia was inconsistently reported, making interstudy generalizations difficult and, more importantly, limiting the broader applicability of findings.

The comparators used were sham surgery^11,13 and no intervention.¹⁰ Both “no intervention” and “sham surgery” are perhaps misnomers, however, since these infant-mother dyads underwent usual care, which could include, but is not limited to, lactation consultation, supportive care, and bottle-feeding advice.

The population studied in the question of benefit of ankyloglossia repair for social concerns included children and adults with wide variation in ages.

Research Gaps

A critical unknown at this point is a good description of the natural history of ankyloglossia by severity, including long-term risk of feeding, social, and speech production difficulties. Future studies should consider direct comparisons of alternative treatments, as currently available literature addressed only the comparison of frenotomy with sham. In order to conduct these studies, it would be helpful if the field could agree on a standardized approach to identifying and classifying ankyloglossia; this would also improve our ability to synthesize the data across studies.

Given variation in outcomes that may be associated with earlier versus later frenotomy, future studies should assess timing of frenotomy to determine whether more significant reduction in maternal pain is achievable by earlier treatment and whether mothers are more apt to breastfeed longer if the frenotomy is done earlier.

A significant gap in research is in understanding the durability of outcomes. Good-quality comparative studies evaluated breastfeeding effectiveness immediately^11,13 or within 5 days of frenotomy;¹⁰ however, none adequately assessed whether effectiveness and other outcomes (e.g., changes in maternal nipple pain) were maintained months or, if appropriate, years later. Longer term followup of both treated infants and controls is needed. Because of the paucity of available data on other feeding outcomes, this entire research question represents a gap and a potential area for future research.

Similarly, substantially more research is needed to consider whether treatment of ankyloglossia in infancy prevents future speech production difficulties, as well as whether treatment later in life with frenotomy leads to improvement when speech problems arise. To conduct this research effectively, methods for evaluating risk and presence of speech production difficulties will need to be standardized, and outcomes agreed on. Understanding of the natural history of speech concerns in children with ankyloglossia is lacking, as are comparative studies that use standardized measurement tools for speech outcomes.

No standard definitions of tongue mobility or established norms for mobility exist, and further research is needed to determine such parameters. Social concerns are difficult to measure objectively, so there will likely always be a subjective component to social outcomes. Larger studies that assess both treated and untreated individuals could provide useful data to minimize the potential bias found in the existing literature. Similarly, future research in objective measurement tools or validated self-report tools is needed.

Conclusions

A small body of evidence suggests that frenotomy may be associated with improvements in breastfeeding as reported by mothers, and potentially in nipple pain. However, with small, inconsistently conducted studies, strength of evidence is low to insufficient, preventing us from drawing firm conclusions at this time. Research is lacking on nonsurgical interventions, as well as on outcomes other than breastfeeding, particularly speech and dental outcomes. In particular, there is a lack of evidence on significant long-term outcomes, such as exclusive breastfeeding at 6 months of age or at 1 year of age, growth, and other measures of health outcomes. Harms are minimal and rare; the most commonly reported harm is self-limited bleeding. Future research is needed on a range of issues, including prevalence and incidence of ankyloglossia and problems with the condition. The field is currently challenged by a lack of standardized approaches to assessing and studying the problems of infants with ankyloglossia.