Collagen and Other Injectable Fillers 

Over the past 30 years, the methods available for the removal or improvement of acne scars and for the correction of wrinkle lines increased exponentially with the advent of new skin filler substances, improved techniques for elevating existing scars, and technology for abrading and resurfacing facial contours. Seemingly every month, a new and improved filling agent or laser, which will be the best of all available methods, becomes available. In the midst of these technological breakthroughs, the basic mechanisms remain the same. Three categories of techniques are presently available to improve acne scars: (1) scar removal and revision; (2) filling depressed scars; and (3) contouring the surface of scars.

Before and after images are below.

The goal for research and development in this field over the past 50 years has been the synthesis of the ideal filler substance for skin and soft-tissue augmentation. The ideal filling material has the following qualities:

• Physiologic - Incorporates itself with the body's tissues
• Simple procedure - Injectable
• Risk free - No complications or adverse effects
• Permanent - Does not degrade with time

This ideal has not been met but it has been the goal in creating all presently available materials.

Physiologic filling materials such as dermis, fascia, and fat have been used as autologous implants for many years, with specific surgical techniques used for each. These remain in use today but on the whole are cumbersome and complicated surgical operations with associated adverse effects and complications. Injectable filling materials included cutting oils, paraffin, and silicone, each with its own adverse effects and complications.

The first Food and Drug Administration (FDA)-approved injectable filling agent, bovine collagen, was approved in 1982 and remains the most commonly used product for skin and soft-tissue augmentation. In fact, Zyderm remains the criterion standard against which all new fillers are compared.

Thirty years ago, one either excised a scar or dermabraded the surface. Combinations of these two methods were beginning along with punch grafts and the use of autodermal grafts. The basic workup and evaluation of these scars remain essentially the same because these choices are available for the types of scars the clinician evaluates for improvement. This review discusses skin-filling agents available for scar correction.

Distensible cutaneous scars are best elevated with filling material. A distensible scar is defined as one that elevates to the surface when tension is placed on either side. This simple test allows the clinician to determine whether a particular scar is likely to respond to filling material. Fibrotic ice pick and fixed scars cannot be elevated because the scar tissue extends through to the subcutaneous tissue plane. Placing filling material in the dermis only elevates the surrounding skin and produces a donut effect, making the scar appear worse.

The ideal skin-filling agent is safe, physiologic, simple, and permanent. No known substance meets all of these criteria. Each of the available substances has adverse effects that detract from these properties, but all are the result of striving to perfect their qualities to fulfill these requirements. The list of injectable filling materials increases each month, with both synthetic and natural substances added. Other implant materials may be placed surgically.

Indications for collagen injection are acne scars, traumatic scars, photoaging, wrinkles, and gravitational rhytides.

Contraindications to this procedure include allergy to bovine collagen, allergy to lidocaine, pregnancy, or a collagen vascular disease such as dermatomyositis or polymyositis.