Which of the following is a known complication of wound healing?

A fistula is indeed recognized as a complication of wound healing. It is an abnormal connection that develops between two epithelial surfaces. This can occur when there is improper healing of a wound, often due to infection, inflammation, or inadequate tissue perfusion. Fistulas can lead to significant morbidity as they may allow for the unwanted passage of fluids or materials between different body cavities or organs, complicating both the healing process and the patient's overall condition.

Scab formation is part of the normal healing process, representing the body's way of protecting the underlying tissue while it heals. Hematomas and seromas are also complications but are more related to fluid collections; hematomas involve blood accumulation, while seromas involve clear serous fluid. While these can complicate healing, they do not represent the same type of abnormal connection that characterizes a fistula. Thus, recognizing fistula formation as a complication of wound healing highlights the importance of understanding the complexities involved in post-operative recovery and the potential for abnormal healing responses.