Final answer:
Plain catgut is contraindicated for procedures that require suture strength retention for more than 21 days, as it is absorbed quickly by the body. For a longer duration of wound support, synthetic materials like PDS or polyglyconate are preferred.
Step-by-step explanation:
Plain catgut is the absorbable suture material contraindicated for procedures that require the suture to retain strength for longer than 21 days. Plain catgut is absorbed by the body relatively quickly.
Sutures are used to close wounds or surgical incisions, and different materials are chosen based on the requirements of the healing tissue. When a wound needs to be supported for a more extended period, as in deep tissue layers, long-lasting suture materials like polydioxanone (PDS) or polyglyconate are typically used. These synthetic materials are designed to maintain tensile strength for weeks to months and are absorbed by the body over a longer period.
Plain catgut, made from purified natural collagen fibers from the intestines of sheep or cows, loses most of its tensile strength within 21 days. The speed at which it is absorbed can be influenced by factors such as infection, the patient's digestive enzyme activity, and the exact nature of the tissue being repaired. Because of this rapid loss of tensile strength, plain catgut should not be used when continuous support is needed beyond three weeks after the surgical procedure.