Efficacy of Laser Debridement on Pain and Bacterial Load in Chronic Wounds

Chronic wounds are a debilitating affliction, affecting a substantial portion of the population worldwide and incurring staggering healthcare economic costs (1,2). Included among chronic wounds are venous leg ulcers, which are known to cause considerable pain, and can impact patient quality of life, thereby complicating wound care (3). The exact pathophysiology and etiology of the prolonged course of chronic wounds are poorly understood, but are thought to be multi-factorial in nature. Given the exposure of chronic wounds to the environment, they harbor a diverse microbial flora. Specifically, there is evidence that biofilm produced by these microbes are a large contributor to their non-healing nature (4). Debridement is considered an integral part of wound management with its ability to remove necrotic tissue and bacterial biofilm, in addition to stimulating release of cytokines and growth factors that promote wound healing (5). However, sharp debridement, the gold standard in wound care, is often ineffective for painful wounds. The effect of lasers on wound healing have been well-studied both in in vitro and in vivo models. Beneficial effects of low-level laser therapy in wound healing in animal and human studies has been established. However, extrapolation of this data is limited by study design and light dosimetry (6). Laser energy used for surgical excision is a lesser-known debridement technique that has been largely limited to burn scar treatment (7,8,9,10). Lasers are electro-optical devices that emit a focused beam of intense monochromatic light in the visible and infrared radiation spectrums. Since their start in the 1960s, lasers have been successfully utilized in many fields of medicine. Lasers for wound debridement began in the 1970s, with the successful report of a continuous-beam carbon dioxide (CO2) laser used for skin graft preparation of infected decubitus ulcers (11). Laser debridement is based on the controlled vaporization of the superficial layers of the wound bed. This results in the removal of the tissue containing unwanted microbial and necrotic particles. The laser type and the number of passes performed determine the depth of tissue ablation (12). Unlike other methods dependent on the clinician's manual control, laser debridement is electronically controlled, improving precision and reducing the risk of healthy tissue damage. Advantages of laser debridement include precision and uniformity of tissue ablation, which reduces trauma to the wound bed, improving patient comfort. To reduce thermal damage to healthy tissue, several improvements in laser technology have been made over the years. By utilizing a pulsed-beam system, laser energy is delivered in high-power, rapid succession pulses, resulting in short duration and high temperature exposure of target tissue, thereby minimizing thermal injury. Erbium:YAG (Er:YAG) lasers, with a wavelength of 2940-nm are widely used in the dermatologic community for skin resurfacing, for anti-aging and acne-related purposes (13). Skin ablation with the erbium laser is very precise, and allows for accurate assessment of the resurfacing depth (12,14,15). Since Er:YAG laser energy has greater than twelve times more water absorption efficiency than CO2 lasers, water in the tissue is rapidly expanded to eject the charred debris from the wound surface without leaving behind a necrotic eschar (12,16,17). The Er:YAG laser provides distinct advantages in precise ablation control and the reduction of residual necrotic tissue burden with minimal procedural discomfort, making the Er:YAG laser the most suitable device for laser wound debridement. Preliminary studies demonstrate remarkable patient pain reduction after laser debridement, resulting in more thorough removal of necrotic tissue and biofilm/bacterial load. Additionally, the extent of laser debridement is determined by the laser settings, as opposed to the individual operator's dexterity and skill, thereby providing better control over the wound bed preparation, producing more predictable and reproducible outcomes.