Офтальмохирургия (Oct 2017)
CHOOSING FREE TRANSPLANTS FOR PLASTIC SURGERY OF THE SCAR-DEFORMED TISSUE OF EYELIDS AND IN THE PERIORBITAL AREA ON THE BASIS OF BIOMECHANICAL CRITERIA
Abstract
Purpose. The paper reports the results of a comparative study of strength-elastic properties of the skin of the upper and lower eyelids, eyebrows, conjunctiva as well as those of free transplants (excess skin of the upper eyelid, skin of the posterior surface of the auricle, the inner surface of the shoulder, the lip mucosa) in normal conditions and scar deformations. Material and methods. In the study 210 standard-size samples were cut from tissues removed during reconstructive plastic surgeries of traumas and burns of the eye and eye adnexa. In order to determine the biomechanical parameters, the samples were loaded until a rupture using the Autograph Universal Testing Machine (Shimadzu, Japan) and checked for the tension-deformation dependence. This dependence was used to calculate the elasticity modulus, the tensile strength, and the maximum longitudinal deformation of the examined tissue. Results. The obtained results revealed differences in strength-elastic parameters of the skin of the upper and the lower eyelids and also the eyebrow area. It was determined, that the elasticity modulus (E) of scardeformed skin in the eyebrow area (Е=6.3±2.1 MPa) was higher than that of the lower eyelid area (Е=4.3±0.8 MPa) and the upper eyelid area (Е=3.6±0.5 MPa). The elasticity modulus of the skin of the inner surface of the shoulder (Е=4.0±0.5 MPa) is close to that of the scar-deformed skin of the lower eyelid, while the value of E for the posterior surface of the auricle is close to that of the upper eyelid scar-deformed skin (Е=2.5±0.4 MPa). The maximum rigidity was found to characterize the conjunctiva with burn-induced scars (Е=3.8±2.0 MPa), while the minimum rigidity was displayed by the conjunctiva of eyes with traumatic lesions without scars (Е=0.7±0.2 MPa). The elasticity modulus of lip mucosa (E=2.2±0.3 MPa), close to the respective parameter of scar-deformed conjunctiva (Е=1.9±0.4 MPa), shows that, from the biomechanical point of views, this tissue can be regarded as fully suitable for plastic surgery of the conjunctiva. Conclusions. Matching biomechanical parameters of periorbital area tissues and free transplants should be considered when choosing the transplants and developing the treatment plan of reconstructive plastic surgeries of traumatic scar deformities of eyelids and the conjunctiva.
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