Here's some info that I've gathered as a patient:
There are several methods of fixing a detached retina, including laser photocoagulation, cryotherapy, scleral buckling, pars plana vitrectomy, and pneumatic retinopexy. Technically, each of the procedures can be done independently of one another. However, depending on the extent of the detachment and other factors the retinal surgeon may choose to use a combination of the above procedures. Depending on your situation the combination may be for extra precautionary measures and/or a more successful outcome, but your surgeon should be able to answer this question. Since any treatment has its risks the doctor generally chooses the least riskiest procedure(s) that he/she thinks will be the most effective for you. It is best to talk to your doctor and make sure you understand why surgery is being performed, what the alternatives are to surgery if any, what risks the surgery poses, what the possible outcomes will be if you choose to not undergo sugery, etc. Lastly, make sure you take care of your other eye. Hope this helps.
is this an added precaution or is it needed for a succesfull procedure