Final answer:
Following a splenectomy, a unique risk is the increased chance of overwhelming post-splenectomy infection (OPSI) due to the loss of the spleen's immune functions.
Step-by-step explanation:
One unique post-operative risk following a splenectomy is an increased susceptibility to infections, particularly those caused by encapsulated bacteria such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. This heightened risk is due to the spleen's role in filtering bacteria and producing necessary antibodies to fight infections. Asplenic individuals, or those without a spleen, require vaccinations and prophylactic antibiotics to reduce the potential for severe infections, a condition known as overwhelming post-splenectomy infection (OPSI).