A clean-contaminated surgical wound is characterized by a controlled entry into a hollow viscus such as the respiratory, alimentary, or genitourinary tracts without unusual contamination. This implies that the surgical procedure involves opening these tracts under sterile conditions, minimizing contamination risk. In contrast, clean wounds have no entry into hollow viscera, contaminated wounds show gross spillage or inflammation, and infected wounds have the presence of pus. Controlled entry is key because it differentiates clean-contaminated from other wound classes and guides antibiotic prophylaxis and wound management.

Reference: Sabiston Textbook of Surgery, Townsend et al., 21st Edition.