Nd:YAG Laser Treatment of Keloids and Hypertrophic Scars.
Journal - Eplasty (United States )
Pathological cutaneous scars such as keloids and hypertrophic scars (HSs) are characterized by a diffuse redness that is caused by the overgrowth of capillary vessels due to chronic inflammation. Our group has been using long-pulsed, 1064-nm Nd:YAG laser in noncontact mode with low fluence and a submillisecond pulse duration to treat keloids and hypertrophic scars since 2006 with satisfactory results. The present study examined the efficacy of this approach in 22 Japanese patients with keloids (n = 16) or hypertrophic scars (n = 6) who were treated every 3 to 4 weeks. Treatment settings were as follows: 5 mm spot size diameter; 14 J/cm(2) energy density; 300 µs exposure time per pulse; and 10 Hz repetition rate. The responses of the pathological scars to the treatment were assessed by measuring their erythema, hypertrophy, hardness, itching, and pain or tenderness. Moreover, skin samples from 3 volunteer patients were subjected to histological evaluation and 5 patients underwent thermography during therapy. The average total scar assessment score dropped from 9.86 to 6.34. Hematoxylin and eosin staining and Elastica Masson-Goldner staining showed that laser treatment structurally changed the tissue collagen. This influence reached a depth of 0.5 to 1 mm. Electron microscopy revealed plasma protein leakage, proteoglycan particles, and a change in the collagen fiber fascicles. Further analyses revealed that noncontact mode Nd:YAG laser treatment is highly effective for keloids and hypertrophic scars regardless of patient age, the origin and multiplicity of scarring, the location of the scar(s), or the tension on the scar.
Visual and Pathologic Analyses of Keloid Growth Patterns.
Journal - Annals of plastic surgery
Keloids grow and spread not only vertically but also horizontally, although hypertrophic scars do not grow beyond the boundaries of the original injury. Clinically, we have encountered keloids with regular and irregular (untypical) shapes. As the characteristics of the irregular growth patterns of keloids have not been studied yet, we analyzed the irregular growth of keloids both visually and pathologically.A total of 220 keloid specimens, each from a different patient, were surgically removed and used in this study. Through visual analysis, the preoperative shapes of these 220 keloids were classified into those with a regular shape (R group) and those with an irregular shape (IR group). Moreover, we distinguished between cases that had received keloidectomy previously and those that had not. We also determined whether the keloids were recurrent keloids or not. In both the R and IR groups, keloid specimens were studied histologically to examine for infection.In the R group, there were 156 cases (70.9%; 55 males and 101 females with a mean age of 33.68 years). Three patients (1.9%) had infection and 2 patients (1.3%) had undergone keloidectomy previously. In the IR group, there were 64 cases (29.1%; 24 males and 40 females with a mean age of 45.27 years). Thirty patients (46.9%) had infection and 24 patients (37.5%) had undergone keloidectomy previously. Statistically, the rates of infection and keloidectomy were significantly different between the R group and the IR group.Severe infection or operative history may be the cause of irregularly shaped keloids. Thus, in the absence of significant infection or a surgical history, the shape of keloids may be determined uniquely by skin tension.
The relationship between keloid growth pattern and stretching tension: visual analysis using the finite element method.
Journal - Annals of plastic surgery (United States )
BACKGROUND: Keloids grow and spread horizontally, like malignant tumors, for reasons that remain unknown. Yet, stretching tension is clearly associated with keloid generation, as keloids tend to occur on high tension sites such as the anterior chest and scapular region. Thus, we analyzed the relationship between keloid growth patterns and stretching tension using a visualized finite element study. MATERIALS AND METHODS: Keloids, normal skin, and fat structures were reproduced using DISCUS software. The contours were transferred to ADINA analytical software to rebuild and mesh volumes. RESULTS: (1) High tension was observed at the edges, and not in the entire region, of stretched keloids. (2) Keloid centers were regions of low tension, which helps to explain the healing that generally occurs in the central regions of keloids. (3) Expansion of a keloid occurred in the direction in which it was pulled. (4) The "crab's claw"-shaped invasion occurred in response to increased stretching tension. (5) Skin stiffness in the circumference of a keloid was associated with greatly increased tension. (6) Fat hardness and thickness did not influence the amount of tension. (7) Adhesion with subcutaneous hard tissue greatly increased the tension in the keloid. CONCLUSION: These stretching results have advanced understanding of keloid formation under various conditions. Our results suggest that stretching tension is an important condition associated with keloid growth.
|ISSN : ||0148-7043|
|Mesh Heading : ||Cicatrix Humans Keloid Skin Tensile Strength Wound Healing physiopathology physiopathology physiology|
|Mesh Heading Relevant : ||Finite Element Analysis physiopathology|
Management of ear keloids.
Journal - Plastic and reconstructive surgery (United States )