Very few. The goal of every operation is to safely accomplish the desired outcome. "mis" allows us to do this with much less pain than traditional surgery, but it should never be at the expense of less safety. Furthermore, the indications for surgery shouldn't change based on technique. A critical measure of competence is the number of prior options performed--be sure to ask your surgeon this question.
Exposure. More exposure to radiation if guided by imaging and less exposure of the site being operated on that could compromise results or lengthen the surgical time based on the problem being treated and on the skill and experience of the surgeon. Increased surgical time can create a higher risk of complications including infection.