Surgical microlaryngoscopy (surgery on the vocal cords) success rates depend very highly on the severity of the damage to your niece's cartialage, the amount of time that has passed (because of scarring), her individual healing abilities and other surrounding injuries.
It is possible that this will take more than one surgery because "reattachment" may mean that the structures are being repaired but she may still be unable to speak. The restoration of vibration to the margain of vocal fold (to help speaking abilities return) means that they will take a fat implantation and use the tunnel and fold technique in a future surgery.
Success rates are not readily availiable because of the rarity of the surgery and the degree that success will be specific to her case elements.
I wouldn't want to leave you with that, which doesn't sound very encouraging. What you can do (as part of your patient rights) is inquire to the hospital where she is being treated at as to the success rates of that specific hospital for these types of surgeries. Because you are a patient, you are also a consumer and it is your right to compare numbers and choose your best options.
The main telephone number for the Children's hospital of PA is(###) ###-#### They may be able to help you futhur if you contact the connelly resource center for families at 215-590-4YOU (4968).
You (and her parents) should never be left at a loss for understanding when dealing with these serious matters. Unfortunately sometimes, doctors and nurses will give you a lot of information at once that may be confusing or overwhelming. It is important to understand that as a patient with rights, you have the right to be informed and you should continue to conference with her doctor as many times as it takes to understand the full situation. You are not "bugging"anyone and it is their job to inform you. Her doctor is the one that knows her own situation and extent of injuries the best and will be able to provide the best information about her prognosis.
I wish you all the luck and hope she has a full recovery.