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Stuart Isaacson, MD: How about anatomical localization? How would you teach someone who doesn’t know how to inject the parotid with anatomical localization?

Richard M. Trosch, MD: With the parotid, these are the boundaries: The inferior boundary of the zygomatic arch down to the anterior edge of the sternocleidomastoid muscle, and then you have it from the mastoid process to the masseter. So it’s really kind of in here.

Stuart Isaacson, MD: It’s a big gland.

Richard M. Trosch, MD: It’s a big gland.

Stuart Isaacson, MD: Hard to miss, perhaps.

Richard M. Trosch, MD: It’s the largest gland. Submandibular lies in inner table of the mandible, and it’s really in the posterior third. So if you go between the chin and the angle of the mandible, you’ll find it in the posterior third, right up, and then the needle has to be pushed in and pushed up toward the inner table. And sublingual we don’t go after.

Stuart Isaacson, MD: Right. How deep do you put the needle in for the parotid gland?

Richard M. Trosch, MD: I use a ½-inch needle if I’m doing only parotid, and it’s not very deep, but it depends on the patient. Because depending on their weight, they may have a different amount of subcutaneous fat, so the subcutaneous layer can vary. That’s again where ultrasound comes in. If someone is very thin, it’s going to be very superficial. You don’t have to go very deep, but in someone who’s heavier, there may be a significant subcutaneous layer that you have to get through. If you’re too far in, you’re in the buccinator or the carotid potentially. And so again, that’s where ultrasound comes in: to let you know what the depth is. By the way, another plug for ultrasound: It’s getting cheaper. My first machine cost about $40,000. I just bought 1 a few months ago. It’s a better machine, and it’s $2000. So if people are not comfortable with an anatomic guidance, it’s a quick, easy procedure to learn, and it’s now fairly affordable.

Stuart Isaacson, MD: And you are offering to buy everyone an ultrasound machine.

Richard M. Trosch, MD: That’s right—and to teach them.

Stuart Isaacson, MD: In the studies, anatomical localization tended to rely on halfway between the angle of the jaw and the external meatus and then bisecting coming 1 finger breadth anterior and with a single injection. Do you use a single injection, or do you use more than 1 injection?

Richard M. Trosch, MD: I know sites that use up to 9 injections. I think 2 injections is common. I’m using a single injection.

Stuart Isaacson, MD: I use a single injection as well.

Richard M. Trosch, MD: I find that works well.

Stuart Isaacson, MD: Yeah. What are some of the adverse effects you talk to patients about when you inject them, to be aware that they could occur?

Richard M. Trosch, MD: When I’m injecting only the parotid, the real concern is dry mouth and what goes with that, which could be dental decay; they have thrush from that. There is a potential if you’re blind, you could hit the facial nerve. If you’re too deep, you could be down here in the carotid. But most of the injections are going to be in this area, so over the bone where carotid and buccinator are not really coming into play. If I’m going back here then I’m very careful to watch for the nerve, watch for the artery, so I don’t hit it. Dry mouth is the big issue. For the submandibular, swallowing is the problem— dysphagia. Even if you’re careful and you put the toxic injectable right in the middle of the submandibular, it doesn’t necessarily stay there, and it can diffuse to other surrounding structures and cause dysphagia.

Stuart Isaacson, MD: Do you involve the dentist at all? If they’re having all this saliva, it could affect their dental hygiene.

Richard M. Trosch, MD: I don’t typically, but I could see dentists doing this procedure for patients as well and certainly otolaryngologists are doing the procedure already. I see this botulinum toxic injectable being useful for a lot of specialties.