Ultrasound-guided Botulinum Toxin-A Injections: A Method of Treating Sialorrhea

The overall goal of this procedure is to provide a simple and reliable method to treat sialorrhea by botulinum toxin salivary gland injection, in order to obtain a long lasting efficacy, and a limited rate of minor side effects. This method can help neurologists and doctors involved in the treatment of sialorrhea to improve their salivary gland botulinum toxin injection technique. The main advantage of this method is that through ultrasound guidance, and simple rules of injection, it is possible to obtain reproducible and long lasting outcome in the treatment of sialorrhea, and limiting potential side effects.

Generally, individuals new to this method will struggle because the use of ultrasound guidance may appear challenging and time consuming. On the contrary, the easy ultrasound identification of the salivary gland and the possibility to inject the small submandibular gland led to the higher treatment success rate. Widening the therapeutic effect duration.

Begin by placing the patient on the ultrasound table in the supine position, with their neck extended. Use antiseptic to disinfect the skin in the area of the parotid and the submandibular glands. Next, turn on the ultrasound systems, and press the start/end button to begin the exam.

Press the probe button to select the high frequency probe. Then, press the patient button to enter the patient's first name, and last name. Press the depth button, and specify the depth of view to five centimeters.

Following that, press the focus button to select the maximum detail of two centimeters. Next, place the transducer under the mandible between the anterior and posterior bellies of the digastric muscle, in order to visualize the submandibular gland, which should appear as a hypoechoic area with homogenous echotexture, compared to the surrounding tissues. Finally, place the transducer below the external acoustic meatus, to visualize the parotid gland, which should also appear as a hypoechoic area with homogenous echotexture, compared to the surround tissues.

For the injection, acquire a 22 gauge needle, and use a lateral short access approach at the widest gland diameter to access the submandibular gland. Inject 25 IU of botulinum toxin, or boNT-A, into the upper submandibular quadrant. After the injection, slightly retract the needle and change the direction of the needle tip towards the lower submandibular quadrant.

Inject another 25 IU of boNT-A for a total of 50 IU in each submandibular gland. Dab any bleeding with steril gauze for one to two minutes. Next, for the parotid gland injection, identify two access sites midway between the external auditory canal, and the mandible angle, where one is in the cranial part of the gland, and the other in the caudal part of the gland.

Then, use the upper access site in the cranial part of the gland to inject 18 to 19 IU of boNT-A into the medial cranial quadrant. After the injection, slightly retract the needle without leaving the site of the cranial part of the gland, and change the direction of the needle tip towards the lateral cranial quadrant. Inject another 18 to 19 IU of boNT-A.

Next, use the lower access site in the caudal part of the gland to inject 18 to 19 IU of boNT-A into the medial caudal quadrant. Then, slightly retract the needle without leaving the site of the caudal part of the gland, and change the direction of the needle tip towards the lateral caudal quadrant. Inject a final 18 to 19 IU of boNT-A for a total of 75 IU boNT-A in the four parotid areas.

Finally, dab any residual bleeding with steril gauze. Keep the patient for one hour to monitor any potential adverse events. Notice, the drooling frequency and severity scale, or DFSS scores, showed a significant reduction in both variables from pre-treatment to one month after treatment.

The visual analog scale used, evaluated the patient's objective sufferance related to the sialorrhea, and showed higher scores, meaning an increase in overall comfort from pre-treatment to one month after treatment. Additionally, the need for daily saliva aspirations also lowered from pre-treatment to the one month follow up. Once mastered, the technique can be completed in about 15 minutes, if it is performed properly.

After watching this video, you should have a good understanding on how to place the transducer in order to visualize the submandibular and the parotid glands, and identify how to move the needle tip in order to treat the whole glandular tissue with the standard botulinum toxin dose. Don't forget, that working with needles can be dangerous. Precaution, such as the use of gloves and safety measures for removal and disposal of needle are always required, to reduce the risk of accidental injury and infectious diseases.