Coding for Magnetically Controlled Spinal-Lengthening Device Procedures

Growing rod constructs have been used for decades to treat early-onset scoliosis (EOS) without creating a definitive posterior spinal fusion that would limit growth. Traditional growing rods typically involve small segment fusions proximally and distally to anchor the rods and a side-to-side or end-to-end connector in the middle of the construct to join the rods and allow for lengthening. Typically, patients return to the OR about every 6 months and the rods are lengthened manually.

More recently, growing rods with internal lengthening mechanisms have been developed. Instead of requiring a return to the OR, the devices can be lengthened with the use of an external remote control that changes the polarity of the internal magnet, causing it to spin and elongate. Magnetically controlled lengthening devices are approved by the FDA and are indicated for treatment of EOS in skeletally immature patients when a definitive fusion would result in an unacceptable loss of spinal height.

Coding guidance
Appropriate coding for insertion of growing rods remains controversial. An informal poll of surgeons who use magnetic lengthening devices found that many typically code using posterior spinal fusion and instrumentation codes from the Spinal Deformity section of the American Medical Association (AMA) Current Procedural Terminology (CPT) manual. Although commonly used, these codes are technically not correct.

The CPT guidelines state: “Select the CPT code of the procedure or service that accurately identifies the procedure or service performed. Do not select a CPT code that merely approximates the procedure or service provided. If no such specific code exists, then report the procedure or service using the appropriate unlisted procedure or service code. When using an unlisted code, any modifying or extenuating circumstances should be adequately and accurately documented in the medical record.”

AMA recently addressed appropriate coding for magnetically controlled growing rods in a CPT Assistant article from December 2022. It concluded that no code in the CPT manual appropriately describes the work involved with insertion of this type of construct. Therefore, the article recommended that surgeons use the unlisted code for spine surgery (22899) to document the work of inserting these devices.

There is no code in the CPT manual for lengthening of magnetically controlled growing rods in an outpatient or office setting using the external remote control. AMA also considered this issue and concluded that the unlisted spine code (22899) is appropriate. When performing a separate evaluation of the patient on the same day as lengthening of magnetically controlled growing rods, it is appropriate to report an Evaluation and Management (E/M) code for a follow-up office visit (e.g., 99212 to 99215) unless the visit is within the global period of the original insertion. If the lengthening is performed within the global period, the unlisted code should be appended with the 58 modifier, as this is a planned procedure. If the visit is beyond the global period, the visit code should be appended with a -25 modifier to indicate that significant and separately identifiable E/M was performed on the same day.

Unlisted codes, such as code 22899, have no associated work relative value units. Typically, surgeons are asked to provide CPT codes that are similar as references for unlisted codes and must negotiate reimbursement amounts with payers individually for each case.

Rod replacement and conversion to spine fusion
There are instances when growing rods reach their maximum lengthening potential and require replacement. Replacement can typically be done with new growing rod constructs if patients remain sufficiently skeletally immature or by conversion to a definitive posterior spinal fusion with instrumentation for more mature patients.

When exchanging growing rods, code 22849, Reinsertion of spinal fixation device, is appropriate to report. Note that although there are separate codes for removal of spinal instrumentation (e.g., codes 22850 and 22852), code 22849 for reinsertion of instrumentation also includes implant removal.

When converting growing rods to a definitive posterior spinal fusion, the appropriate posterior spinal fusion code (22800 to 22804) should be included based on the number of included vertebral segments, along with code 22849 for reinsertion of spinal implants.

It is hoped that one day there will be a consensus to allow for the creation of new codes specific to magnetically controlled lengthening devices to accurately describe the work involved and enable tracking of these services.

Kevin M. Neal, MD, MBA, is a member of the AAOS Coding, Coverage, and Reimbursement Committee; represents the Pediatric Orthopaedic Society of North America; and is a pediatric spine surgeon in Jacksonville, Florida.

R. Dale Blasier, MD, FAAOS, FACS, is an orthopaedic surgeon at the University of Arkansas for Medical Sciences in Little Rock, Arkansas. He is the current chair of the AAOS Committee on Coding, Coverage, and Reimbursement.

Matthew Hepler, MD, FAAOS, is a representative of the Scoliosis Research Society and a member of the AAOS Committee on Coding, Coverage, and Reimbursement.

Christopher Kauffman, MD, FAAOS, is a representative of the North American Spine Society and a member of the AAOS Committee on Coding, Coverage, and Reimbursement.