Spinal instrumentation, also known as spinal implants, devices or hardware is a surgical method of attaching the implants into the spinal region to restore the spinal stability. These implants are usually made of titanium, titanium-alloy, stainless steel or non-metallic devices. There are different types, shapes and sizes of spinal implants available in the market now to treat various spinal disorders in people of all ages and gender.
What is the purpose of Spinal Instrumentation?
Enhance the fusion process: The primary role of spinal instrumentation is to provide additional stability to the spine while helping the fusion set up. Usually the bones tend to fuse more effectively where there is little motion and instrumentation helps the fusion process by limiting the motion at the fused segment.
Restore spinal stability: When pathologic processes (example: tumor, infection, fracture) compromise spinal stability, spinal implants can restore stability.
Correction of spinal deformities: Spinal deformity is produced by variety of reasons like trauma, infection, degeneration and idiopathic reasons. Instrumentation is useful in achieving and maintaining spinal correction.
Components of a Spinal Implant:
A complete implant assembly is termed as a “Spinal construct”. Typically, spinal instrumentation construct consists of the following components:
- An anchor describes the portion of the implant or construct that is fixed to the bone.
- It includes pedicle screws, cables, and hooks.
2. Longitudinal members:
- The longitudinal members are the parts of the implant to which the anchoring devices are attached.
- It includes rods or plates.
- These are devices that connect anchors to the longitudinal members or connect two longitudinal members (cross-connectors).
- It includes lock screw connectors, circumferential grip connector and constrained bolt- plate connectors.
Washers and rod sleeves are notable accessories.
Types of Spinal Implants:
In general, the types of implants may be classified as fusion and non-fusion implants:
These are implants combined with bone graft.
Examples of fusion implants: rods, plates, screws, plates, interbody cages
These are implants used without bone graft.
Examples of non-fusion implants: growth sparing devices and artificial discs.
Growth sparing devices are used in patients, such as children, who have not reached skeletal maturity. Devices such as the Vertical Expandable Prosthetic Titanium Rib (VEPTR) may be used to treat scoliosis.
Coding Spinal Instrumentation:
When you start coding the spinal instrumentation procedures, you must definitely look for the terms plates, screws or rods to qualify for the instrumentation procedure performed. If any instrumentation or fixation was placed, then check whether it was posterior, anterior or intervertebral approach to pick up the correct codes.
Instrumentation is coded by “construct” type and by the number of levels or interspaces involved, along with the anatomical placement of the instrumentation.
It refers to the instrumentation attached to the back of the spine or vertebral segment. There are many different configurations of posterior instrumentation and are described as below with the corresponding codes:
Non-segmental instrumentation, posterior – 22840
Per CPT definition, the Non-segmental instrumentation is defined as “fixation at each ends of the construct and may span several vertebral segments without attachment to the intervening segments.” In simpler terms, it attaches to the spine at two points only, one at the top and the other at the bottom of the construct.
Example: Harrington rod technique
Segmental instrumentation, posterior: 22842 – 22844
Per CPT definition, the Segmental fixation is “defined as fixation at each end of the construct and at least one additional interposed bony attachment. In simpler terms, it attaches to the spine at three or more points, including the proximal and distal portions of the rod or other device, depending on the number of vertebral segments spanned.
- 3 to 6 vertebral segments – 22842
- 7 to 12 vertebral segments – 22843
- 13 or more vertebral segments – 22844
Internal spinal fixation by wiring of spinous processes – 22841
Pelvic instrumentation – 22848
It refers to the instrumentation attached to the front of the spine or vertebral segment, towards the front of the body. Depending on the number of vertebral segments spanned, anterior instrumentation is reported using the following codes:
- +22845 Anterior instrumentation; 2 to 3 vertebral segments
- +22846 Anterior instrumentation; 4 to 7 vertebral segments
- +22847 Anterior instrumentation; 8 or more vertebral segments.
As the codes are framed up with the term “vertebral segment”, you should be cautious in counting the vertebral segments. Most of the coders get confused with the term “vertebral segment and interspace”. Definition for both the vertebral segment and interspace is provided below to eliminate any confusion in the terminologies.
A vertebral “segment” represents a single complete vertebral bone with its associated articular processes and laminae. A vertebral “interspace” is the non-bony area between two adjacent vertebral bodies and it contains an intervertebral disc. For example, L3-L5 comprises of three vertebral segments and two interspaces.
Biomechanical devices: (synthetic cages, mesh):
Codes: 22853, 22854 and 22859
There are three codes listed as below to report the insertion of biomechanical devices. These codes typically differ in two aspects:
- Location of the device insertion (intervertebral disc space or the vertebral body defect) and
- WITH arthrodesis procedure or WITHOUT arthrodesis procedure.
Code 22853 is used to report the insertion of interbody biomechanical device to intervertebral disc space in conjunction with interbody arthrodesis, each interspace.
Code 22854 is used to report the insertion of intervertebral biomechanical device to vertebral body defect in conjunction with interbody arthrodesis, each contiguous defect.
Code 22859 is used to report the insertion of intervertebral biomechanical device to intervertebral disc space or vertebral body defect without interbody arthrodesis, each contiguous defect.
Happy learning! Happy coding!