To reiterate, personally I am a supporter of this procedure but it is worthwhile to understand where naysayers are coming from.
So what data is out there currently?
The Holy Bible contains a passage that loosely could be interpreted to suggest tongue tie release:
"And looking up to heaven, he sighed, and saith unto him, Ephphatha, that is, Be opened. And straightway his ears were opened and the string of his tongue was loosened, and he spoke plain." (Mark 7:34-35) [link]Tongue tie release was considered controversial in ancient history with Aristotle (3rd century BC) and Paul of Aegina (7th century AD) being supportive, but Celus (1st century AD) and Galen (2nd century AD) arguing against. Even in the middle ages, the benefit of tongue tie release was controversial among midwives (who used their fingernail to cut the tongue tie) and surgeons (who used surgical instruments).
This controversy continues even into modern times. In the year 2000, in perhaps the largest survey of lactation consultants (n=350), speech language pathologists (n=400), ENTs (n=423), and pediatricians (n=425),
"69% of lactation consultants, but a minority of physician respondents, believe tongue-tie is frequently associated with feeding problems. 60% of ENTs, 50% of speech pathologists, but only 23% of pediatricians believe tongue-tie is at least sometimes associated with speech difficulties. 67% of ENTs versus 21% of pediatricians believe tongue-tie is at least sometimes associated with social/mechanical issues. Surgery is recommended at least sometimes for feeding, speech, and social/mechanical issues by 53, 74, and 69% of ENTs, respectively, but by only 21%, 29%, and 19% of pediatricians." [link]In terms of actual evidence-based research, only 20 studies were identified in a pubmed literature search summarized in a meta-analysis published in 2013.
"Of those, 15 studies were observational and 5 were randomized controlled trials. Tongue-tie division provided objective improvements in the following: LATCH scores (3 studies); SF-MPQ index (2 studies); IBFAT (1 study); milk production and feeding characteristics (3 studies); and infant weight gain (1 study). Subjective improvements were also noted in maternal perception of breastfeeding (14 studies) and maternal pain scores (4 studies). No definitive improvements in speech function were reported. The only significant adverse events were recurrent tongue-ties that required repeat procedures." (Abbreviations: IBFAT: infant breastfeeding assessment tool; LATCH: latch, audible swallowing, type of nipple, comfort, and hold; SF-MPQ: short-form McGill pain questionnaire.) [link]The meta-analysis went on to conclude that:
Ankyloglossia is a well-tolerated procedure that provides objective and subjective benefits in breastfeeding; however, there was a limited number of studies available with quality evidence. There are no significant data to suggest a causative association between ankyloglossia and speech articulation problems. Aspects of ankyloglossia that would benefit from further research are described, and recommendations for tongue-tie release candidacy criteria are provided... [procedure should be performed only] in newborns with significant ankyloglossia and associated breastfeeding problems who have failed conservative managementSummary
Just because quality data is lacking does not mean tongue tie release should not be performed. In fact, definitive research may not be possible given bias would be nearly impossible to eliminate. Parents and doctors will have preconceived notions of the kinds of pathology tongue tie may cause and understandably, parents can't help but desire a certain course of action rather than put their child into a randomized research situation. Even the intervention itself cannot be blinded as it will be clear to all which child underwent a tongue tie release or not.
The only truly unbiased participant in any future research attempted is probably the innocent child himself who has no preconceived notions beyond signals the parents may send.
Alternatively, more objective testing may need to be utilized to determine effectiveness or not. For example, breastfeeding improvement based on ultrasound measurements can be further developed and used as an objective test.
In the end, it takes a considered evaluation by all who is caring for the infant and ultimately, the parents need to decide whether tongue tie release is worth pursuing or not. From a parental perspective, what may be the most frustrating part of tongue tie evaluation is the potentially radically divergent opinions that may be proffered by lactation consultants, pediatricians, speech language pathologist, and ENTs.
I should also mention that even adults get tongue tie release performed due to symptoms felt secondary to an immobile tongue.
The effect of tongue-tie division on breastfeeding and speech articulation: a systematic review. Int J Pediatr Otorhinolaryngol. 2013 May;77(5):635-46. doi: 10.1016/j.ijporl.2013.03.008. Epub 2013 Mar 26.
Much Ado about Nothing: Two Millenia of Controversy on Tongue-Tie. Neonatology 2010;97:83–89
Ankyloglossia: controversies in management. Int J Pediatr Otorhinolaryngol 2000; 54: 123–131.
Frenulotomy for breastfeeding infants with ankyloglossia: effect on milk removal and sucking mechanism as imaged by ultrasound. Pediatrics. 2008 Jul;122(1):e188-94. doi: 10.1542/peds.2007-2553. Epub 2008 Jun 23.
Tongue movement and intra-oral vacuum in breastfeeding infants. Early Hum Dev. 2008 Jul;84(7):471-7. doi: 10.1016/j.earlhumdev.2007.12.008. Epub 2008 Feb 11.
Does frenotomy help infants with tongue-tie overcome breastfeeding difficulties? J Fam Pract. 2015 February;64(2):126-127.
Treatments for Ankyloglossia and Ankyloglossia With Concomitant Lip-Tie. Comparative Effectiveness Review Number 149
Treatment of Ankyloglossia for Reasons Other Than Breastfeeding: A Systematic Review. Pediatrics. 2015 May 4. pii: peds.2015-0660. [Epub ahead of print]