Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Values are presented as 95% confidence interval (CI).
a)Operative level including cervical, thoracic, lumbar, or more than one type of level; b)Bleeding volume including intra operative and postoperative blood loss.
