This is often referred to by parents as “opening the ear canal”. The purpose of opening the ear canal is to restore hearing by allowing outside sound to pass through the surgically opened channels to the middle and inner ear. To explain this procedure, let’s review the structure of a normal child’s ear. The normal ear consists of three major parts: the outer ear, the middle ear and the inner ear. The outer ear includes the auricle and the external auditory canal, and serves to pick up sound and transmit it to the middle ear. Sound waves are converted into mechanical vibrations in the eardrum (the division between the outer and middle ear). The auditory chain in the middle ear (the hamate, anvil and stapes from outside to inside) transmits the mechanical vibrations further to the inner ear. The inner ear perceives the vibrations, converts them into neural electrical signals, and transmits them to the brain, where they finally form the sense of hearing. In this process, the role of the external auditory canal, tympanic membrane and auditory chain is to conduct sound signals. Children with microtia usually have a narrow or even atretic external auditory canal, an undeveloped tympanic membrane, and a malformed or absent auditory chain. Abnormalities in any of these three parts of the external auditory canal, the tympanic membrane and the auditory chain can block the transmission of sound signals and cause deafness. In clinical practice, we find that malformations of the outer and middle ear often occur simultaneously: in most children, not only is the external auditory canal atretic, but also the tympanic membrane and the auditory chain are malformed. Probably, parents can also think of how the so-called external auditory canal and tympanoplasty is done: surgically, an external ear canal is opened and the tympanic membrane and the auditory chain are reconstructed at the same time. This is a simple procedure to imagine, but in practice it involves many complex surgical operations: What is the diameter of the external ear canal that needs to be opened on the bone plate? How to implant the skin? How to ensure the stability of the implanted auditory tuberosity? How to maintain the proper thickness of the reconstructed tympanic membrane? Among these techniques, the most difficult to control is the re-narrowing or atresia of the external ear canal after the surgery, that is, “the ear canal grows back”. The human body has some wonderful properties, such as the tendency of the human tissue to revert to its original structure (whatever it was at birth, there is always a tendency for it to grow back to the way it was at birth, no matter how much surgery or intervention is done later). This is also reflected after ear canal reconstruction in small-eared children: if a child is born without an external ear canal, I am able to make an external ear canal out of the child through surgery, but some reconstructed external ear canals slowly grow narrower and narrower, and the child loses hearing again. This is a process that usually takes 1.5 to 2 years. Of course, clinically we still have measures to open up the external ear canal and implant it during surgery so that it is less likely to narrow; or use a rigid ear mold after surgery to fill in the external ear canal to help expand it – but the tendency for the external ear canal to grow small and atretic again, still exists. It follows that external ear canal reconstruction – tympanoplasty (open ear canal), is usually only suitable for children who already have an external ear canal themselves (although it may be narrow or tiny), or for children with less severe atresia deformities themselves (score 7 or more). Such babies, we are aggressive in performing external ear canal reconstruction – tympanoplasty, because they have a reconstructed external ear canal that can be stable for a long time after surgery and the child’s reconstructed hearing can be maintained for a long time.