Why is everyone so afraid of partial removal of problematic submandibular glands in fixing cobra neck deformity?

First off, the purpose of submandibular gland removal is not to fix a cobra deformity. If you don’t like the “flat appearance” of your neck, taking out the gland might make it worse. I don’t recall your previous photos.
Second, I wouldn’t say doctors are “afraid” of partial gland removal. It’s just a matter of risk benefit ratio and familiarity with the procedure. The safest way to take out a gland is by making a direct incision but it leaves a scar. The posterior facial artery is best identified with a wide exposure. However, to avoid a scar with a facelift, exposure is limited by going through the preauricular or the submental incision. To access the gland, the submental incision has to be slightly longer to avoid working in a hole. True access to the gland means going under the platysma or through it. Incising the platysma eithout good exposure increases the risk of marginal mandibular nerve injury and without good exposure increased risk of bleeding from the facial artery and posterior facial vein and thus a risk of post op hematoma. A post op arterial bleed in a neck with full skin elevation from a facelift can result in a bull neck which can be potentially serious. I don’t think dry mouth is a real complication. I’m well versed in total submandibular gland removal and never really see dry mouth.  There are six major submandibular glands to the area. To those who shave submandibular prominence shows on top of the platysma might just be shaving fat and weakening platysma muscle. Usually partial gland removal requires the proper risk benefit ratio to make it worthwhile, but it is a difficult approach and is not innocuous.

Cobra neck deformity usually is the result of over zealous resection of fat from the submental region in combination with platysma muscles not reapproximated during a necklift.  Removing the submandibular glands will not remedy these issues.  In terms of partial submandibular gland resection dry mouth is probably the least of the problems that can occur if not performed flawlessly.  Facial nerve injury is by far the number one potential complication and it can occur when the gland is removed with full surgical exposure.  

 Thank you for your question.    There are possible complications but the most important part is that the surgeon is familiar   with the surgery and you indeed need the surgery.

That can't tell you how often shaving the submandibular gland causes dry mouth because they do not measure it. The data we have is for patients who for various reasons have the gland removed.  The biggest problem with partial resection of the gland is that it is a very deep structure for cosmetic surgery with very important structures running through it. In particular, bleeding during the procedure can be very problematic. It is estimated that about 20% of patients will have a motor nerve weakness and or dry mouth after the procedure. Looking at your photos that you have posted, I see neither a prominent submandibular gland nor a cobra deformity.  Don't make surgeons fix problems you don't have.

One of the facial nerves run through this gland and it could be damaged. If this occurs you end up with a deformity of the lower lip. The side damage would not move. You need to see a board certified Plastic Surgeon not a facial plastic.

 A full set of pictures and in-person examination going to be required to make a determination about how best to proceed. The anatomy in the neck is extremely complicated which includes skin, muscles, and fatty deposits above and below the platysma muscle in addition to the submandibular glands. A partial resection of the submandibular glands can be accomplished along with a platysma plasty with permanent sutures to help with the cobra conformity.

doctors  will find reasons not to do things they don't want to do. Removing glands is something very few surgeons have been trained to do and most will find another excuse to continue not doing it. It is not an innocuous procedure and has potential big complications You should first ask if they do the procedure at all, it will save you time. It would also help if you send a picture