IDN block in patients with large tongues
The "classical" technique of performing an IAN block involves inserting the needle just anterior to the pterygomandibular raphe at a level in the middle of the occlusal plane at the height of the deepest concavity of the anterior border of the ramus from an angle aiming from the contralateral premolar region.
Multiple factors can hinder ideal placement of the needle including trismus, lack of hard and soft tissue landmarks, patient anxiety and a large tongue.
A large tongue tends to spread out over the occlusal surfaces of the lower teeth and move laterally and may actually block the site of injection in severe cases.it may also rise upwards especially if the patient is anticipating pain and hinder the correct angulation of the barrel of the syringe lying across the arch.
Rather than instruct the patient to move their tongue to the side which almost always causes them to spasm their tongue in random directions, attempt to have the patient's head in different positions. Sitting them up may allow the tongue to drop downwards towards the floor of the mouth in high tongue cases. Lying them back may allow the tongue to drop back if they are protruding however it also tends to allow the tongue to spread laterally. Turning their head to the contralateral side slightly may allow gravity to pull their tongue to one side.
If this fails, then your assistant can hold a mouth mirror or minnesota retractor to pull the tongue out of the way or depress the tongue. The floor of the mouth is a moveable object and the tongue can be compressed downwards in most circumstances. Sometimes in the obsese, this can be a challenge as the floor of mouth tends to be tense and the tongue quite large.
If this fails you can consider clueing the patient in on the difficulty of the procedure and ask them to move their tongue to one side. This can open up a small passage to allow injection however you will rarely have enough room for ideal angulation.If they move their tongue to one side and no space opens up then simply tell them to move it to the opposite side and see if that works. Have the needle ready to go and insert as soon as space opens up as they often can't hold this position for long.
Any combination of these techniques can allow you to insert the needle into the tissue. Once inside, you are not worried about injecting into the tongue and you can change the orientation of the barrel and use the syringe to compress against the tongue to the ideal angulation. Ensure you have at least a cm of the needle inserted or this sudden movement may cause bending of the needle in the tissue and make its removal difficult.
If the tongue is very large and the patient cannot reach the right position or other factors such as trismus are hindering proper needle placement and alternative technique is the Akinosi nerve block which avoids syring angulation over the tongue.
Multiple factors can hinder ideal placement of the needle including trismus, lack of hard and soft tissue landmarks, patient anxiety and a large tongue.
A large tongue tends to spread out over the occlusal surfaces of the lower teeth and move laterally and may actually block the site of injection in severe cases.it may also rise upwards especially if the patient is anticipating pain and hinder the correct angulation of the barrel of the syringe lying across the arch.
Rather than instruct the patient to move their tongue to the side which almost always causes them to spasm their tongue in random directions, attempt to have the patient's head in different positions. Sitting them up may allow the tongue to drop downwards towards the floor of the mouth in high tongue cases. Lying them back may allow the tongue to drop back if they are protruding however it also tends to allow the tongue to spread laterally. Turning their head to the contralateral side slightly may allow gravity to pull their tongue to one side.
If this fails, then your assistant can hold a mouth mirror or minnesota retractor to pull the tongue out of the way or depress the tongue. The floor of the mouth is a moveable object and the tongue can be compressed downwards in most circumstances. Sometimes in the obsese, this can be a challenge as the floor of mouth tends to be tense and the tongue quite large.
If this fails you can consider clueing the patient in on the difficulty of the procedure and ask them to move their tongue to one side. This can open up a small passage to allow injection however you will rarely have enough room for ideal angulation.If they move their tongue to one side and no space opens up then simply tell them to move it to the opposite side and see if that works. Have the needle ready to go and insert as soon as space opens up as they often can't hold this position for long.
Any combination of these techniques can allow you to insert the needle into the tissue. Once inside, you are not worried about injecting into the tongue and you can change the orientation of the barrel and use the syringe to compress against the tongue to the ideal angulation. Ensure you have at least a cm of the needle inserted or this sudden movement may cause bending of the needle in the tissue and make its removal difficult.
If the tongue is very large and the patient cannot reach the right position or other factors such as trismus are hindering proper needle placement and alternative technique is the Akinosi nerve block which avoids syring angulation over the tongue.
Aiming at the height of the sigmoid notch? Isn't that too high?
ReplyDeleteHi, yes you're right. I'm referring to the deepest concavity of the anterior border of the ramus of the mandible. The sigmoid notch refers to the vertical concavity between the condyle and the coronoid process. At uni, the anatomy lecturer called the anterior ramus notch the sigmoid notch and obviously that was wrong but stuck with me. That being said, The angulation of the needle should be midway between the occlusal planes on full opening and most people don't open wide enough for your blocks. So it would benefit you to aim at the level of the anterior ramus concavity with a slightly higher angle or just aim at a slightly higher needle isnertion point.
DeleteThanks for your comment