One thing that is important to note before answering your question is that coding for transforminal epidurals/selective nerve root blocks differs from coding for Medial branch blocks/facet blocks.
For example if the physician states he did a Left L4 and Left L5 selective nerve root block. He is directing the needle between L4-L5 level at the L4 foramen and performing the injection where the nerve root exits. The same procedure would be performed at L5-S1 for accesing the L5 Foramen using fluoroscopy with both procedures this would be 64483 LT 64484 LT 77003.
But if the physician states I blocked the L4 medial branch/facet joint nerve and L5 dorsal ramus you are then looking at what medial branches innervate the corresponding facet joint, so then you think L4 and L5 innervate the L5-S1 joint so only 64493 would be coded.
In your example L5,S1,S2,S3---this hard to answer due to fact the last facet joint is L5-S1 so the nerves in the sacral area would not innervate that final facet joint. If the physician feels S1 provides innervation to L5-S1 this would still be included in medial branch L4, L5 dorsal ramus as only one cod even though L4,L5, S1 (medial) is listed.
yes the commas versus dashes are crucial in precerting to coding to post payment review . You have confirm that the op report is referring to the medial branches versus the anatomical locations where the injection were adminstered. Since there is 8th Cervical nerve, this makes the innervation below the C7 level, set up as the branch above and at the level providing innervation . Such as L1, L2 would innervate the L2-L3 joint (64493), then L2,L3 would innervate the L3-L4 joint, L3,L4 would innervate L4-L5 joint (64495). So you would see 4 medial branches blocked (4 needles) but in order to compliantly bill these procedures you count per joint level which would leave you with 3 levels. There is a current CPT Assistant article where this is describe I think Oct 10 and then Sept 04 is great article which you could order thru the AMA bookstore CPT Assistant back issues or get the CPT Assistant archives 1999-2010. This can be describe better and in greater detail. Reviewing CPT Assistant articles on facet joint coding and listening to webinars or go to seminars can make it more understandable and provide a more in depth analysis.