Are there any labs that will test breastmilk for silicone leakage after torn cohesive gel implants?

If you are that concerned and have ruptured implants, you should remove your implants regardless of what a lab tells you. At the end of the day you need to be comfortable and based on the current evidence there is negligible/ no evidence of silicone in the milk in patient with intact implants.  As a matter of fact, the medication given to treat baby colic has more silica gel which it is made of than anything they have ever noted in breast milk. But if you have leaking implants they should be removed whether you are or are not breast feeding.

Breast milk can be tested for the presence of silicone... but one study showed the amount of silicone in in formula is 10,000x more than that in breast milk with silicone implants.

You can have the breast milk sent to a pathology lab to look for refractory particles consistent with silicone. They will not be found and even if so they would be harmless.