Removing salivary stone (sialolith) from the sublingual duct

 Yesterday I observed one of the OMFS at work remove a sialolith about 8mm diameter from a sublingual duct. He said it was quite rare to see such a large one make it so far distal down the duct. It was almost near the midline so had made it to the exit of the duct but was too large to escape. 

The aetiology is a calcification forms in the duct and gathers more calcium and phosphate as it travels down the duct and eventually becomes too large to escape and gets stuck. This stone was quite superficial and so was palpable intraorally. A very superficial mucosal incision was made not directly over the stone as scar tissue would form over the duct exit. He then used curved hemostats to blunt dissect the mucosa off the gland tissue and separate the gland tissue apart until the stone was located in the duct. Prior to the procedure starting he put in quite a lot of anaesthetic, a whole cartridge was put in underneath the stone's position causing quite a bit of swelling to the area. this caused hydrodissection of the sublingual gland and made the stone's position easier to feel and locate.

I was surprised to see how superficial the acini were to the tissue surface. As soon as he made his incision, gland tissue bulged out of the wound. It made me realise most of the time when I am giving a lingual infiltration in the area of the anterior teeth, I am injecting directly into this gland tissue. 

He preferred to use a non-rat tooth tweezer to hold the tissue edge open probably to avoid damaging the thin tissue surface. The tissue dissecting took the longest portion of the procedure as he had to open space to locate the stone in the duct. Once he had done this, he used his finger to push the stone more proximal away from the duct exit. This was because the incision was made proximal to the stone's position. When he had gotten the stone to a good position, he used the tweezers to get under the stone and pinched them under the stone to secure it in place. Then he used a scalpel to perform a ductotomy i.e open the wall of the duct to allow the stone to be extracted. He got the tweezers and held one side of the duct wall and gave this to the assistant to hold. Then he teased the stone out with the the hemostat. 

After the duct wall was incised and the stone was starting to mobilise, quite a lot of backed up saliva was leaking out proximal to the stone. The whole area was irrigated well with saline and suctioned up. There was very minimal bleeding as the only cuts made were in the thin mucosa at the tissue surface and the duct wall and all other manipulations were with blunt dissection.

Suturing was done with vicryl simple interrupted sutures. The tissue was extremely fragile and plenty of care had to be taken to not tear the tissue. I noticed that the initial bite of the suture was done by passing the needle through the mucosa but the second bite was done with the needle stationary and the tweezers were used to push the tissue through the needle. It was important that the needle only passed through mucosa and not pick up any glandular tissue or any of the duct. When tying the knots, he was very careful not to pull the wound edge either way, instead tightening the knot with equal pressure on both ends of the suture. The suture ends were cut very short for patient comfort. After the sutures were tied, he dried the saliva from the floor of mouth and then put pressure on the sublingual area to see if any saliva came out of the duct. If this fails to happen then the duct may have been picked up in the sutures and he would rather take the sutures out and redo it as suturing the duct would result in another blockage and a reformation of the sialolith. The duct if left alone will heal on it's own and doesn't need to be closed at all.