Test sites are important to the success of some implants, including Zyderm, Zyplast, Koken and Fibrel because they minimize the risk of an allergic reaction. Most physicians perform two tests at approximately one month intervals. A small amount of the implant material is injected into the second layer of the skin on the inside of the arm. if the skin becomes inflamed and itchy at the test site then an allergic reaction has occurred. In this case, another type of implant material may be tried. If this is also unsuccessful then implant therapy as an option for the treatment of deep wrinkles may have to be abandoned.

Although Hylaforrn viscoelastic gel is in its infant stage as a soft tissue implant, it would appear from all reports that it does not require test sites as allergic reactions are very rare. Microlipid transfers do not require preimplant tests, because the implant consists of fat from another area of the same body.

Once it has been determined that an allergic reaction will not occur the physician can proceed with the implant therapy The selected material is injected into the second layer of the skin along the wrinkle. Depending on how deep the crease is, a second layer of implant solution may be required.

If Zyderm or Zyplast are used, the physician will overcorrect, raising the line of the crease above the surface of the skin. This compensates for the anesthetic within the implant solution and will flatten out within a short period of time as the local anesthesia wears off. Once the implant is in place the physician may massage the treated area to feather out the line of correction.

Gore Tex and SoftForm implants are not injected but threaded along the furrow or depression targeted for correction. A local anesthetic is used to numb the area before and tiny incisions are made at either end of the insertion line. A tunnel is then created through which the GoreTex or SoftForrn implant is threaded.