Modifier 50 is applicable when:

Modifier 50 is specifically applicable when bilateral procedures are performed during the same session on both sides of the body. This means that when a single procedure is done on both sides, the use of Modifier 50 signals to the payer that the procedure was performed bilaterally. It allows for proper reimbursement that reflects the dual nature of the service provided.

In contexts where procedures are performed independently or simultaneously but only on one side, or where anesthesia is involved irrespective of the procedural location, Modifier 50 would not be applicable. The focus of this modifier is strictly on the bilateral nature of the procedure, which is what makes it the correct answer in this scenario.