Following are some of the possible risks associated with this procedure. When performed in a proper setting by an experienced professional, your risk of these complications is very low:
Bleeding: The tongue is an extremely vascular organ. When cut with a knife (scalpel), it may bleed excessively. Surgical tools such as electrocautery will be able to reduce the bleeding to an ooze, and may even stop it. If the split is performed with electrocautery rather than a knife, bleeding will be far less an most likely nominal.
Asymmetry: Unevenness between sides is a reality of the human body. When the tongue is unified, the unevenness between the sides of the tongue is seldom evident. However, once split, the unevenness may become more evident. This is true even in cases in which the tongue was perfectly split down the middle. Because all patients will have at least some degree of asymmetry (which is usually mild), it is best to expect this at the outset.
Salivary gland duct obstruction: The salivary glands sit in the floor of the mouth and deliver salivary fluid to the mouth in response to stimulation by food. That salivary fluid squirts into the mouth through the tiny ducts on either side of the frenulum (the little tether between the undersurface of the tongue and the floor of the mouth). Those tiny ducts are important because if they get obstructed, they may cause the entire salivary gland to get infected. That can be a serious problem. The tiny ducts can get obstructed if your surgeon attempts to split your tongue so deeply that the split is close to the ducts and causes scar tissue to form near the duct openings. This is one of the many reasons that each patient’s anatomy is the determining factor regarding the depth of split possible.
Regrowth: Your surgeon will presumably split your tongue as far back as anatomically possible based on the length and thickness of your tongue and the position of your submandibular ducts. Your surgeon will also presumably close the dorsal side to the ventral side along the split (see surgery to see how this is done). Even in spite of these steps, there is always at least some degree of “regrowth” which is healing together at the depth of the split. Typically regrowth is usually about 10%, no matter what you or your surgeon does.
Nerve damage: Some websites suggest that nerve damage is “likely” and in fact an “unavoidable” part of this procedure. This is absurd. The tongue is a midline structure. The splitting of the tongue, if performed properly, is accomplished along the midline of this midline structure. There are no nerves which cross the midline of the tongue, and no nerves at risk for damage. Whereas you will likely have temporary numbness along the split, the sensation here will be fully regained. With regard to motor nerves, the hypoglossal nerve, which moves the tongue, is nowhere near the split and is not at risk. So, the suggestion that there will be nerve damage following this procedure is absolutely unfounded. Anyone suggesting that nerve damage is a “typical” consequence of this procedure should not be performing tongue splitting.
Infection: Given the vascularity of the tongue, infection is nearly unheard of in this operation. The rate is so low that this should not be a significant concern of yours.