The Effects of Z Plasty On Hypertrophic Scars

Abstract

Hypertrophic scar tissue has been observed to soften and thin following Z plasty without removal of any of the scar tissue. Histochemical studies of tissue before and after Z plasty showed that abnormally sulfated mucopolysaccharides were replaced by normal acid mucopolysaccahrides within 14 days. Collagen in hypertrophic scar appeared in nodules and fibers perpendicular to the surface of the skin rather than as long straight fibers parallel to the skin surface as normally seen. Elastic fibers were reduced and scar was relatively avascular. Following Z plasty the amount of collagen decreased and fibers were oriented in bundles at right angles to each other, parallel to the surface. When tissue was examined by electron microscopy collagen fibers showed marked variation in diameter. Microfibrils were increased and there were aggregates of fibrils with periodicity of 1500 to 1600 A. Following Z plasty, areas which previously contained only microfibrils now had unit collagen fibers with normal periodicity. Urinary excretions of hydroxyproline and hydroxylysine, amino acids found only in collagen, were increased following Z plasty, coinciding with the softening of the scar. Excretion of the disaccharide, glucosylgalactosylhydroxylysine, predominantly found in skin, increased following Z plasty, while excretion of the monosaccharide, galactosyl-hydroxylysine, predominant in bone collagen, remained constant. Amino acid composition of collagen, remained constant. Amino acid composition of collagen isolated from hypertrophic scars was similar to that present in skin and tendon, and unlike that in cartilage or infant dermis. Hydroxyproline content was slightly decreased and hydroxylysine content slightly increased compared to skin or tendon. Histochemical, ultrastructural and biochemical studies of the same specimens suggested that collagen with disordered fibril formation was present in the hypertrophic scar and was degraded following Z plasty. Changes in the molecule which occurred after synthesis of the protein core might be responsible both for the failure of normal maturation of the scar and for its sensitivity to degradative enzymes following Z plasty.

Mechanical load initiates hypertrophic scar formation through decreased cellular apoptosis

“…The relatively low resting tension of murine skin also suggested that the intrinsic forces in murine skin might not be sufficient to activate the processes that lead to human hypertrophic scarring. This, in addition to extensive clinical evidence (3,7,10), served as the rationale for using an external tension device to augment the biomechanical forces on murine skin and replicate the forces normally experienced by human skin in a murine model.…”

Drying stress and damage processes in human stratum corneum

“…1. Such damage can ultimately lead to tissue responses including inflammation, scarring and abnormal desquamation and further exacerbate the effects of skin disorders such as atopic dermatitis, ichthyosis vulgaris and chronic xerosis [8][9][10][11][12][13][14].…”

The Use of CO2 Fractional Photothermolysis for the Treatment of Burn Scars

“…Such procedures, however, require a more invasive operation and do not improve the existing superficial meshed pattern. 26,27 The fractional CO 2 laser is a relatively new modality that attempts to break up the tension across a hypertrophic wound, incite collagen turnover, and allow for a more "normal" wound healing process to take place. 10,14-17 Similar to a Z-plasty, the laser breaks up the thick, disorganized collagen fibrils that created the scar, allowing these regions to reheal in a more organized fashion.…”

“…10,14-17 Similar to a Z-plasty, the laser breaks up the thick, disorganized collagen fibrils that created the scar, allowing these regions to reheal in a more organized fashion. 16,26,27 Objective assessment of scars is notoriously difficult, and existing scales, such as the Vancouver scar scale, are difficult to standardize. Furthermore, the time course for scar maturation is inconsistent and dependent on multiple known and unknown variables.…”