Neurosurgery Coding Alert

Along with the usual concerns of properly reporting multiple procedures and avoiding bundled codes, confusing medical terminology and the need for precise documentation make reporting nerve graft procedures (64885-64902) especially challenging. Careful communication between surgeon and coder and some basic instruction reduce the challenge considerably.

CPT describes nerve graft procedures by location, length and as "single strand" or "multiple strand (cable)" (see sidebar on page 59 for a complete list and definitions of applicable codes). The distinction between single- and multiple-strand grafting is fundamental to coding and requires a basic understanding of nerve anatomy.

The simplest analogy to a nerve is a telephone cable. If you cut a telephone cable you will see several individual color-coded strands of wire. Imagine that each strand within the cable further comprises several finer strands, much like woven rope or the multi-strand electrical cable that connects loudspeakers to your home stereo system. In the nerve, the finest strands (axons) combine to form larger parallel strands (nerve bundles, fascicles or funiculi), which are equivalent to the color-coded wires in a phone cable. The nerve bundles further combine to form the nerve.

Rather than splicing two ends of a cut nerve (neurorrhaphy), nerve grafts involve suturing a portion of nerve tissue, usually harvested from the sural nerve, into a gap caused, for example, by trauma or excision of neuroma (e.g., 28080, Excision, interdigital [Morton] neuroma, single, each) between the proximal and distal ends of a severed nerve. A single-strand graft describes a graft sutured end-to-end with the proximal and distal portions of the damaged nerve. Returning to the phone-cable analogy, the ends of the cable are joined, but the color-coded wires within the cable are not spliced together. The nerve is left to heal and re-establish the appropriate connections on its own.

During a multiple-strand or cable graft, the surgeon employs microsurgical techniques to rejoin the individual nerve bundles within the nerve, much like carefully splicing together the color-coded wires within the phone cable (except without the color-coding, and at a much finer scale). Because the graft is more precise, nerve regeneration and performance are generally improved when compared to the single-strand graft.

Note: For more information, visit: http://cal.nbc.upenn.edu/saortho/chapter_65/65mast.htm#surgtechniq.

Surgeons performing grafts should clearly describe the procedure as either single- or multiple-strand and specify the length placed for each nerve. Stating, "Repaired brachial plexus using sural nerve graft harvest" is not clear enough. Accusations of fraudulent coding and possible monetary penalties are at stake.

For example, the difference between 64890 (Nerve graft [includes obtaining graft], single strand, hand or foot; up to 4 cm length), with 27.16 relative value units (RVUs), and 64896 ( multiple strands [cable], hand or foot; more than 4 cm length), with 34.09 RVUs, is about $250. Yet, you can easily confuse the codes if the surgeon does not describe the procedure adequately. More appropriately, the surgeon might document, "Harvested 6-cm graft from sural nerve to repair brachial plexus. Nerve bundles individually joined under operating microscope." With this information, you can now confidently report 64898 (Nerve graft, multiple strands [cable], arm or leg; more than 4 cm length).

Note: Mention of the operating microscope is an indicator but not a guarantee of a multiple-strand graft. If documentation is unclear or does not give all pertinent information, check with the operating surgeon for clarification before assigning a code.

Add-on codes 64901 and 64902 describe each additional nerve graft, single and multiple strands, respectively. Therefore, if the surgeon repairs two or more nerves using grafts, report 64901-64902, as appropriate. Modifier -51 (Multiple procedures) or modifier -59 (Distinct procedural service) is not necessary with add-on codes, says Dari Bonner, CPC, CPC-H, CCS-P, a coding and reimbursement specialist for Xact Coding and Reimbursement Consulting Inc. in Port St. Lucie, Fla.

Also, 64901-64902 should be reported instead of modifier -50 (Bilateral procedure) to describe nerve grafts placed bilaterally (nerve graft codes include a "0" indicator in column "S" of the Physician Fee Schedule, indicating that modifier -50 is inappropriate). However, in those cases when nerve grafts are placed bilaterally, you may append modifiers -LT (Left side) and -RT (Right side) to differentiate the procedures and avoid accusations of "double billing," says Eric Sandham, CPC, compliance educator for Central California Faculty Medical Group, a group practice and training facility associated with the University of California at San Francisco in Fresno.

For instance, returning to the example of brachial plexus repair above, the surgeon places identical grafts on the right and left side. Correct coding is 64898-LT, 64902-RT. If the graft on the right is a single strand, you should report 64898-LT, 64901-RT.

CPT and Medicare specifically allow +69990 (Microsurgical techniques, requiring use of operating microscope [list separately in addition to code for primary procedure]), if performed, with 64885-64898. Because 69990 is also an add-on code, payers should reimburse for its full RVU value (5.9 RVUs, or about $214).