Forces on sutures when closing excisional wounds using the rule of halves

To close elliptical excisions, surgeons commonly use the rule of halves which involves initially closing of the middle portion of the wound, followed by closure of the remaining halves. Understanding the forces required for suturing such wounds can aid excisional surgery planning to decrease complications and improve wound healing.

Following full thickness excision for removal of skin cancers, back wounds with 3:1 ratio of length-to-width were closed using the rule of halves. The force required to bring the wound edges into contact at the middle portion of the wound was measured, followed by the two bisected halves.

The average force to close the center of the wounds averaged 3.7 N and was six times larger than that of the bisected halves. The forces to close the bisected halves were consistently small, and essentially negligible (<0.5 N) for ~50% of the cases.

When planning excisional surgery to avoid complications such as tearing the dermis (cheese wiring), the use of special wound closure techniques (high tension and/or pully sutures, skin support or suture retention devices, etc.) should focus on the center suture only when using the rule of halves, as the remaining sutures require very low forces.