Mary,
Since this was a separate incision and the fusion is not subsequent I would report 22554 -59 for the additional fusion site. This follows the guidelines for modifier 59 since it is a separate incision and also follows CPT Assistant from November 2007 regarding procedures that are not subsequent. Although the question pertains to instrumentation, the same concept applies.
Question: What is the appropriate code to report if anterior instrumentation is inserted at vertebral segments C3-4 and additional instrumentation is inserted at C6-7, but vertebral segments C4-5 and C5-6 are not fused? Are the anterior instrumentation codes assigned strictly by the TOTAL number of spinal segments with instrumentation applied (ie, 22846) or is the appropriate code chosen based on the vertebral segments involved in each separate construct (ie, 22845, 22845 59)?
Answer: Anterior instrumentation codes 22845-22847 may be reported separately with modifier 59, Distinct procedural service, appended when the procedure involves the work of putting two separate plates in the spine at different locations. Therefore, in this clinical scenario, it would be appropriate to report CPT code 22845, Anterior instrumentation; 2-3 vertebral segments, for C3-4 and CPT code 22845 with modifier 59 for C6-7.