is 22 appropriate?
I would caution against using the 22 modifier for a couple reasons. The first is that it will automatically trigger a manual review, and you will need to send medical records with your 2nd claim when requested. This additional work can take time, and delay payment of your claim for a relatively small procedure.
Also, by definition modifier 22 states "When the work required to provide a service is substantially greater than typically required, it may be identified by adding modifier 22 to the usual procedure code. Documentation must support the substantial additional work and the reason for the additional work (ie, increased intensity, time, technical difficulty of procedure, severity of patient's condition, physical and mental effort required)."
I would not say that simply removing another calculus is substantially extra work, makes the procedure more difficult or greatly increases time, technical difficulty of physical and mental effort.