"Because a lead array contains at least four to eight electrodes, the plural use of the term "electrodes" occurs in the descriptors of the peripheral nerve neurostimulator codes (64553-64565). The catheter or plate or paddle type of electrode array used in brain, spinal cord, sacral, and peripheral nerve stimulation all have multiple electrode contacts. Using present CPT coding convention, in spinal cord stimulation (codes 63650-63680), as an example, reporting is based on the number of electrode catheter or electrode plate or electrode paddle "arrays" inserted."
As you can see from the above CPT Assistant article, you can bill per lead. The thing that I have noticed is that you have make sure they are actually doing an incision to bill 64575 versus using 64555 which is done percutaneously. The times the doctors have performed these where I work they are performing in a way that is resembled with 64555.