Submental loose skin - Would a single incision surgery be sufficient? (Photo)

Good question. The procedure you are looking for is called a Direct Necklift. Other than directly excising the waddle skin, it also involves suturing a thin muscle called the platysma along the front edge of the neck to create a smooth muscle surface on the front of the neck to prevent Platysmal bands. To see if you have these muscle bands, clench your jaw to expose as many of your lower teeth as possible. Note that the side walls of the waddle is actually made of muscle and not just skin. When you clench your jaw, instead of having a single waddle run down the middle, the two bands tent the skin out on the left and right side and the middle part goes up to form two muscle bands. The left and right muscle bands need to be sutures together like buttoning up a dress shirt. If you leave the sort unbuttoned and lean forward, the left and right side of the shirt will hang down not unlike the left and right platysma muscle bands. If you button the shirt and lean forward the front of the shirt stays smooth which is what we want for the front of the neck. The skin removal is also important, to remove the excess skin, but the foundation (deep work) is also very important. The incision is usually made irregular to prevent webbing at the junction of the chin and neck (cervicomental angle). Incisions healing across a joint that can bend ~90-120 degrees can result in a web not unlike the web of skin between your thumb and index finger. Thus a z-pasty or other pattern may be used to prevent that from happening.
Hope that helps. Keep doing your research. Good luck. Best, Dr. Yang

It would take much more than a single incision to help your problem. It would require lift pulls from both sides and maybe even a third incision for midline tightening. Your solution requires a face and neck lift.

The photographs demonstrate loose and inelastic skin in the face and neck, jowls, platysma muscle cords, and fat deposits located above and below the platysma muscle itself. At 61 years of age, you're going to require a lower face and neck lift procedure to address all of these facial changes of aging issues. This involves placement of one incision in front and behind each ear, and a small 1 inch incision underneath the chin.