In the normal healing process of trauma, collagen synthesis and degradation are eventually in balance. When this balance is disturbed or disrupted, it causes excessive collagen synthesis and deposition, forming collagen tissue masses called keloid, so keloid is a soft tissue benign tumor formed by massive proliferation of connective tissue after skin injury.
The keloid is initially pink or dark red, and then gradually forms a hard, irregularly bounded, smooth, shiny, capillary-dilated rubbery plaque that is clearly elevated above the skin surface and grows in a crabfoot pattern, often with typical pedunculated branches. It often occurs secondary to trauma, burns, scalds, earring irritation, injections, and after surgery. Keloid scars are often accompanied by itching, tingling and other discomforts that affect the patient’s quality of life. Large keloid scars that occur in the joint area can restrict limb movement and even affect work and life, and occurring on the face can be disfiguring.
The general treatments for keloid scars include physical therapy, surgery, medication and x-ray therapy, but all have their limitations and indications. The mechanism of treatment is that the isotope on the applicator releases beta radiation during the decay process, which acts on the collagen-producing fibroblasts in the scar tissue, and the fibroblasts are denatured by ionizing radiation, thus reducing the synthesis and deposition of collagen and achieving the purpose of treatment.
Generally, surgical excision with isotope dressing (commercial dresser strontium-90 or homemade dresser phosphorus-32) is more effective. For most scars with small scope, short disease period and good postoperative incision healing, surgical excision is performed first, and isotope dressing is performed the day after stitch removal. For scars with large scope, polymorphic damage, irregularity, long duration of disease, surface infection or breakage, poor healing of incision after surgery, and wired knot reaction, we should consider waiting for complete healing of incision before performing isotope dressing.
In addition, if superficial radiation has been used within 6 months, surgical excision and isotope dressing should not be performed at this time to avoid poor incision healing and radiation dermatitis.