Final answer:
When the defect from a pilonidal cystectomy is too large to close, a wound vacuum-assisted closure (VAC) is typically used to promote healing and recovery.
Step-by-step explanation:
In a pilonidal cystectomy, when the defect is too large to close, a wound vacuum-assisted closure (VAC) is often used. This technique involves using vacuum-assisted drainage to remove blood or serous fluid from the wound or surgical site, which helps to speed up the recovery process. It is a common approach in situations where other suturing techniques like running subcuticular sutures, figure-of-eight sutures, or purse-string sutures are not feasible due to the size of the defect.