Even experienced coders can face a dilemma when trying to describe certain common procedures. Differentiating among procedures that may be bundled together and determining when a more extensive procedure code is more appropriate than a less extensive one are two common areas of confusion. A review of the following common coding errors is intended to help clarify these areas.
Osteotomy Codes
When complex spinal procedures are performed in areas of prior surgery, the
role of osteotomy codes (22206-22226) in spinal surgery may be considered.
The purpose of an osteotomy is to reconstitute an arthrosed joint to restore
mobility. The surgeon uses chisels or drills to separate vertebral segments
to restore motion, often followed by a new arthrodesis across the restored
joint after correction of the deformity. In 2008 a new series of posterior
osteotomy codes (22206-22208) was developed to reflect the work of three-column
posterior osteotomies performed for deformity correction. These codes require
bone resection of posterior elements (facets and pedicle) in addition to
anterior elements (vertebral body and disc space).
In contrast, the previous posterior osteotomy codes (22210-22216) described single-column osteotomy (posterior elements only). The common coding mistake involves using osteotomy codes for initial or re-exploration discectomy and arthrodesis, typically in the anterior cervical spine. For example, the surgeon describes using a chisel or drill to perform an osteotomy of bridging bone spurs to enter the disc space in order to perform a decompression in the spinal canal. Although the tools used may imply to the coder that an osteotomy has been performed, the fact that a discectomy was performed is evidence that an arthrosed joint was not present. Consequently, either an arthrodesis code alone (22554) or in combination with a decompression code (63075) for more extensive discectomy would best describe the procedure.
Corpectomy Codes
Another area of frequent error involves the use of corpectomy codes. According
to the AANS Coding Guide, the use of corpectomy codes (63081-63091) requires
resection of more than half of the vertebral body in the cervical spine and
more than one third of the vertebral body in the thoracolumbar spine. The
intent of corpectomy codes is to describe at least the resection of the central
portion of the vertebral body overlying the spinal canal from the superior
interspace down to the inferior interspace. The common coding mistake involves
using the corpectomy codes to describe partial vertebral body removal, typically
with a drill, during the performance of an anterior discectomy. In order
to achieve a working channel within a narrow interspace, the surgeon may
choose to remove the margins of the adjacent vertebral bodies to provide
sufficient room to access the spinal canal. Rather than the work reflecting
“two corpectomies,” it simply facilitates the anterior discectomy for decompression.
Several methods, including the operative note and examination of postoperative
imaging, can provide clues regarding the extent of vertebral body removal
to determine if resection thresholds have been achieved. The absence of an
anterior lumbar discectomy code has led some coders to mistakenly use the
anterior lumbar corpectomy code (63090) to describe an anterior lumbar discectomy
in preparation of the interspace for an anterior lumbar interbody fusion
(22558). Although uncommon, an anterior lumbar discectomy for decompression
should be coded with an unlisted code (64999).
Stereotactic Codes
Lastly, a common coding mistake occurs in the area of the stereotactic codes
(61720-61795 and 61863-61868). Since there are codes for navigational procedures
(61795) and for stereotactic head frame placement (20660), some coders will
use these codes in addition to the primary stereotactic procedure performed.
The code descriptor parenthetical for 20660 (that delineates a separate procedure)
is a clue that the code is typically bundled into other more extensive procedures.
The stereotactic series of procedures includes the work of stereotactic frame
placement, when used, as well as the work for navigation. Consequently, codes
20660 and 61795 should not be reported in addition to the primary stereotactic
procedure.
These are just a few examples of the subtle intricacies of neurosurgical coding. Beyond reading the code descriptors, resources such as the AANS and American Medical Association publications and courses as well as National Correct Coding Initiative edits can enhance understanding of the proper use of neurosurgical codes.
Gregory J. Przybylski, MD, chair of the AANS/CNS Coding and Reimbursement Committee, represents the AANS on the American Medical Association’s Relative Value Scale Update Committee. He instructs coding courses for the AANS and for the North American Spine Society. He is a member of the Practicing Physicians Advisory Council to the Centers for Medicare and Medicaid Services, and he is a consultant to United HealthCare and Humana Inc.