It is a relatively common practice for a vein specialist to perform multiple procedures during one sitting. Having several procedures done simultaneously saves you the expense of paying the operating room and anesthesia costs more than once.
However, having too much done at one time can lead to complications. The decision to have multiple procedures done depends on which procedures are being done, the extent of the procedure, the operating time, and your age/health.
Ultimately, the physician decides whether or not it is appropriate to include more than one procedure in your operation.