Orthopedic Coding Alert

If your surgeons use the term "uniplane" or "multiplane" in their external fixation op reports, count yourself among a lucky few. But if you-re like most coders and have to search for a few clues to decide between 20690 and 20692, our experts have the answers you need.

Two basic types of external fixation exist today: uniplanar and ring fixation, says Bill Mallon, MD, orthopedic surgeon and medical director at Triangle Orthopaedic Associates in Durham, N.C.

Helpful: "Multiplane fixation and ring fixation are basically synonymous now," though there are exceptions, Mallon adds. "So if you see ring fixation mentioned, you should code for multiplane fixation."

Your coding differs for uniplane and multiplane fixation, says Leslie Follebout, CPC-ORTHO, coding department supervisor at Peninsula Orthopaedic Associates in Salisbury, Md.:

- Uniplane: You should report 20690 (Application of a uniplane [pins or wires in one plane], unilateral, external fixation system).

- Multiplane: You should report 20692 (Application of a multiplane [pins or wires in more than one plane], unilateral, external fixation system [e.g., Ilizarov, Monticelli type]).

Coders may find deciding between uniplanar and multiplanar codes to be tricky, Follebout says. But if you look for these clues in your op reports, you-ll be one step closer to choosing the proper code.

Code 20692's descriptor includes Ilizarov and Monticelli types as examples of multiplane external fixation systems, so if you see either of these terms, you should home in on 20692.

Ilizarov in focus: An Ilizarov system "looks like a series of bicycle wheels placed around the extremity (most often the leg), connected by thin wires," Mallon says.

"The Ilizarov device is still available, but most trauma companies make a variant of it. You can look for the term Ilizarov, or ring fixation, but it may go by another name," he says.

Hybrid tip: A hybrid is multiplanar because it combines a ring fixator and uniplanar fixator, Mallon says.

Other terms, such as "spanning," which means "goes across a joint," don't help you determine whether to use the uniplane or multiplane code.

Good news: There are a few more clues you can look for to keep you on the right track.

Surgeons use uniplane fixators almost exclusively for shaft fractures, especially midshaft tibia fractures, such as 823.20 (Fracture of tibia and fibula; shaft, closed; tibia alone) or 823.30 (- shaft, open; tibia alone), Mallon says.

Surgeons typically fix most intra-articular fractures in the leg with ring fixation, Mallon says. These fractures include tibial plateau (knee) (such as 823.00, Fracture of tibia and fibula; upper end, closed; tibia alone), tibial plafond (824.8, Fracture of ankle; unspecified, closed) or pilon (ankle), he says. The appropriate diagnosis may be 823.80 (Fracture of tibia and fibula; unspecified part, closed; tibia alone), 823.82 (- fibula with tibia), 823.90 (- unspecified part, open; tibia alone) or 823.92 (- fibula with tibia), based on the surgeon's documentation.

The pin the surgeon uses may point you in the right direction to choose between 20690 and 20692.

Uniplane fixators use thicker, more solid pins for fixation than multiplane fixators, Mallon says. Ring fixator pins are much narrower, and the surgeon places them under tension, he says. "So if you see the terms -thin wire- or -thin pin,- or see a description of -tensioning- the pins, this is almost certainly a ring, or multiplane, fixator," he says.

Don't miss: If you see the term "olive wire," you are definitely coding a ring fixator, Mallon says. The term refers to some of the thin wires that have a protruding end. Surgeons never use these wires with uniplane fixators, Mallon says.

"Uniplane fixators usually have the pin drilled into the bone, but not out of the opposite side of the extremity," Mallon says.

Surgeons drill ring fixator pins through the bone and out of the extremity's other side, he says.

When the femur or humerus requires external fixation, the surgeon is much more likely to choose uniplane fixation, Mallon says.

"Distal extremities are much more amenable to ring fixators. The tibia and forearm accept a ring fixator more readily," he adds.

The pelvis is an exception, though, Mallon says.

And coders may have particular difficulty with pelvic cases, Follebout says.

Example: Suppose the patient's fixation device allows the patient to lie flat -- which means it has no true rings -- but the bars do go up and cross over the pelvis.

Solution: The pelvis falls outside of the rule that ring and multiplanar fixation are synonymous, Mallon says. "The pelvis rarely gets true ring fixation, but almost any external fixation system placed on the pelvis must, by definition, be multi-planar," he says.

Remember, uniplanar means occurring in one plane -- the device is essentially straight and flat. Multiplanar means occurring in more than one plane, so if the device has bars going up (one plane) and across (another plane), the device is multiplanar.

Play it safe: CPT 2008 revised more than 50 fracture care codes- descriptors to allow you to report external fixation separately, so keeping 20690 and 20692 straight is more important than ever before. If you have any doubt about whether the surgeon applied a uniplanar or multiplanar device, ask for clarification.

Payoff: In 2008, the physician fee schedule assigns 20690 12.95 fully transitioned facility relative value units (RVUs). Code 20692 has nearly twice as many at 23.84, which adds up to several hundred more dollars in reimbursement. Medicare statistics show three times the number of allowed services for 20690 as for 20692, so be sure you don't miss any legitimate chance to report the multiplanar code.