I found the answer in the CMS guidelines. Under B4 Body part,
B4.1b
If the prefix "peri" is combined with a body part to identify the site of the procedure, and the site of the procedure is not further specified, then the procedure is coded to the body part named. This guideline applies only when a more specific body part value is not available.
Examples: A procedure site identified as perirenal is coded to the kidney body part when the site of the procedure is not further specified.
A procedure site described in the documentation as peri-urethral, and the documentation also indicates that it is the vulvar tissue and not the urethral tissue that is the site of the procedure, then the procedure is coded to the vulva body part.
A procedure site documented as involving the periosteum is coded to the corresponding bone body part. O71.5 is correct.