Indented surgical scars occur when the skin’s repair process results in a depression below the surrounding skin level. Dermatologists call this an atrophic scar, meaning the tissue volume is simply insufficient to fill the original wound. Understanding why this sinking happens is the first step toward correcting the contour and texture of the skin. The final look of any scar is determined by a complex biological process, and a lack of structural support pulls the skin surface downward.
Why Scars Sink: Collagen and Tissue Loss
The core reason a surgical scar sinks is the failure of the body’s natural healing cascade to provide adequate structural volume. During healing, the body attempts to replace lost tissue with a new matrix, primarily composed of collagen. An indented scar forms because the body either failed to produce enough new collagen or the organization of the new collagen fibers is inferior, leading to a volume deficit compared to the surrounding healthy skin.
Another major factor is the loss of underlying tissue, such as fat or muscle, which provided support before the injury. If the surgery resulted in the significant removal or destruction of this subcutaneous padding, the surface skin lacks a foundation. This lack of deeper tissue support causes the skin to collapse inward, creating the sunken appearance.
A mechanical reason for the indentation is the formation of fibrous bands, referred to as tethering, that pull the skin surface down. These bands are scar tissue that adheres the dermis to deeper, underlying structures like fascia or muscle. When the skin is pulled taut by these internal attachments, it creates a visible depression on the surface. This mechanical tension prevents the scar from rising to the level of the surrounding skin.
Distinguishing Indented (Atrophic) Scars
The sunken appearance places the surgical scar in the category of an atrophic scar. The defining characteristic is that it lies below the plane of the surrounding normal skin, creating a depression. This is distinct from other common types of scars formed by an overproduction of tissue.
For comparison, a raised scar is classified as either hypertrophic or keloid, both resulting from an excessive accumulation of collagen during healing. A hypertrophic scar is thick and elevated but remains contained within the original wound boundaries. A keloid scar is a more aggressive form of raised scarring where the tissue grows beyond the edges of the initial injury.
Recognizing that the scar is atrophic confirms the issue is a lack of volume, not an excess. This identification is important because effective treatments for a sunken scar are fundamentally different from those used to reduce raised scars. The goal of treatment for an atrophic scar is to elevate the depressed tissue and rebuild lost structural support.
Professional Treatment Options
Correcting an indented surgical scar typically involves clinical interventions aimed at physically elevating the depressed tissue and stimulating new collagen growth. One immediate and effective treatment is the use of injectable dermal fillers. These substances, often composed of hyaluronic acid, are injected beneath the scar to add volume and lift the depressed area. Fillers provide instant results but are temporary, requiring repeat treatments as the body metabolizes the material over several months to a year.
For scars firmly pulled down by internal fibrous attachments, a technique called subcision is employed. This procedure involves inserting a specialized needle or cannula beneath the skin and using a motion to manually break the tough, fibrous bands tethering the scar to the deeper tissue. Releasing these restrictive bands allows the skin to spring upward. The minor trauma also encourages the body to deposit new collagen in the space created, further improving the contour.
Laser resurfacing offers a non-invasive approach using focused light energy to improve the scar’s texture and color. Ablative lasers, such as CO2 or Er:YAG, create controlled micro-injuries in the skin, triggering a powerful wound-healing response that includes new collagen production. Stimulating collagen synthesis helps the laser gradually fill in the depression and blend the scar with adjacent skin over time. The best outcomes are often achieved by combining methods, such as subcision to release tethering, followed by filler injection for immediate volume, and laser treatments for long-term remodeling.