Mechanical behavior of chemically treated ostrich pericardium subjected to uniaxial tensile testing: influence of the suture

Abstract

The mechanical behavior of sutured ostrich pericardium was studied by uniaxial tensile testing. One hundred forty-four tissue specimens were assessed: 96 sutured samples (48 in which a centrally located suture was placed at an angle of 90 degrees with respect to the longitudinal axis, whereas in the remaining 48, a centrally located suture was placed at a 45 degrees angle to the longitudinal axis, in sets of 12 samples each, sewn with sutures made of Gore-Tex, nylon, Prolene, or silk), and 48 unsutured controls. Each group of 24 samples sewn at one angle or the other with the different suture materials was assayed together with a corresponding control group of 12 unsutured samples. The mean tensile strengths in the unsutured controls ranged between 30.16 MPa and 43.42 MPa, whereas those of the sutured sets ranged from 14.68 MPa to 21.91 MPa. The latter presented a statistically significant loss of resistance (p < 0.01) when compared with the unsutured tissue samples. The angle of the suture with respect to the longitudinal axis influenced the degree of shear stress produced by the suture, as well as the behavior of the different suture materials used. The set of samples sewn with Prolene appeared to be that most sensitive to changes in the angle of the suture, whereas tissue sewn at a 45 degrees angle with Gore-Tex presented lower shear stress values in comparison with samples in which the other three materials were used. A method of tissue selection based on morphological and mechanical criteria was used to ensure the homogeneity of the results in such a way that the coefficients of determination (R2) for the stress/strain curve fitting equation ranged between 0.888 and 0.995. This excellent fit made it possible, applying regression analysis, to predict the mechanical behavior of a specimen by determining that of a contiguous tissue sample. Thus, it should be possible, at least theoretically, to characterize the behavior of a specific region or zone of the biomaterial. In conclusion, ostrich pericardium exhibits strong resistance to rupture, even when sutured. The selection method used ensures the homogeneity of the samples and, thus, of the results. The angle of the suture with respect to the longitudinal axis, where the load is centered, determines the shear stress produced by the suture and the mechanical behavior of each suture material.

Changes in the Mechanical Properties of Chemically Treated Bovine Pericardium After a Short Uniaxial Cyclic Test

“…The need for new, safe bioprostheses requires the in‐depth study of the mechanical behavior of the biomaterial employed as well as its microstructure and the changes it undergoes when subjected to dynamic forces (11). It would also appear to be important to continue research with novel biomaterials that might guarantee greater mechanical resistance (19) and, finally, with innovative systems for the early detection of valve failure, such as the implantation of microsensors and nanofibers that could transmit the slightest variation in the hemodynamic behavior of a cardiac valve leaflet to an external receiver (20).…”

Mechanical strength of sutured block copolymers films for load bearing medical applications

“…The literature is mainly focused on examination of mechanical behaviour of sutured biological materials for cardiac bioprostheses, with leading contributions by Garcia Paez at al. [18][19][20][21][22][23][24]. There are no reports on tensile testing of sutured synthetic materials for soft polymeric cardiac prosthesis.…”

Mechanical resistance of a new biomaterial, ostrich pericardium, and a new method of joining tissues combining suturing and a biological adhesive

“…However, initial experimental studies demonstrated its high degree of resistance to rupture, tolerance to the suture, and acceptable homogeneity in terms of sample procurement and results. 1,2 On the other hand, current experience in the use of adhesives in medicine, and specifically in the field of cardiovascular surgery, is very limited. Their utilization in inert tissues, such as bioprostheses or implants, raises fundamental questions with regard to their mechanical resistance and stability over time.…”