Figure 5The principle of membranous wall splinting is to stabilize and add rigidity in the case of membranous malacia and to also reconfigure the normal shape of the trachea in the case of cartilaginous malacia. Typically, in cases of membranous malacia, the trachea is of normal size (approximately 2.5 cm from side to side in the adult), and thus, the membranous wall is not redundant and is simply reinforced with sequential rows of mattress 4-0 sutures placed in a partial-thickness fashion through the membranous wall. Typically, 4 sutures are placed across the membranous wall, with the lateral sutures also catching a small bite of the lateral cartilaginous wall of the trachea. In cases of cartilaginous malacia, the membranous wall is usually rather redundant and needs to be plicated to reduce its width. The surgeon needs to estimate the degree of reduction in the width of the membranous wall that would recreate the D shape of the trachea. This can be done by pinching the middle of the membranous wall together and assessing the shape of the cartilaginous trachea until the desired shape and size are achieved. The distance between the lateral walls of the trachea is then measured and used to cut the appropriate size of the stabilizing material. We first used a polypropylene mesh for membranous wall stabilization, reasoning it was easy to use, was flexible, but did not stretch, and resisted infection. Most surgeons continue to use it. I no longer use it as I have had 2 patients develop late erosion of the mesh into the airway, which created a very difficult problem with no ready solution for these patients. I currently use extra thick acellular dermis with good medium-term results. We tried polytetrafluoroethylene (PTFE) once, but the patient developed fluid collections between the PTFE sheet and the membranous wall that caused obstruction of the airway. Whatever is used must be safe to provide stabilization of the airway for decades but not erode into either the esophagus or airway. Different sutures are used for fixing the splinting material to the membranous wall. These include 4-0 polypropylene and PDS sutures. Again, it is not clear what is the best suture material to use—permanent or temporary. It is not uncommon when attempting to place partial-thickness sutures that they are actually full thickness into the airway, thus potentially introducing bacteria next to the splint and a foreign body into the airway. PDS eventually dissolves, thus eliminating the foreign body in the airway issue but potentially would allow the repair to weaken and fall apart with time. I currently use PDS suture with good results but do not have 10-year follow-up yet.