Ellipse Technologies, Inc. first developed what is now known as the MAGEC magnetic rod technology nearly 10 years ago. The device was originally cleared by the FDA as an intermedullary nail system for limb lengthening and was later adapted to treat pediatric spinal deformity in growing children.
The spine applications drew the attention of NuVasive, Inc. which acquired Ellipse Technologies in 2016 for up to $410 million. NuVasive, a pure player in the spine device industry at the time focused on continuing to develop the MAGEC rod for the pediatric scoliosis market. However, NuVasive’s newly formed orthopedic division, NuVasive Specialized Orthopedics, continued to develop a nail system and launched the updated Precice Stryde in 2018, similar to the original Precice nail, but capable of bearing weight.
Prior to the introduction of the magnetically controlled nail, the most common method of limb lengthening or salvage after osteotomy due to trauma or tumor resection was the use of the Ilizarov frame, an external fixator system.
For large defects, bone transport was necessary. In this procedure a standard intermedullary nail is inserted, a segment of healthy bone is cut and slowly moved along the nail to encourage growth across the gap. With an external fixator, wires are inserted through the skin and fixed to the bone to be moved and the frame.
A concern with external fixators is the zones of necrosis left by the wires as they are dragged through the skin as the frame is adjusted. This can leave scarring and possibly lead to infection. A more recent development is the use of balanced cable transport, a cable-to-nail system, which uses internal cables during the limb lengthening process and replacement with a nail at a later time. This option reduces some of the risks and scarring of the external wire method.
The Precice and Precice Stryde from NuVasive takes the process completely internal. The magnetically controlled intermedullary nail contains a gear system that can be turned with an external magnetic controller. The Precice Stryde swaps the titanium nail for stainless steel which allows for up to 5 times as much weight bearing, enough to allow a patient to walk even early in the healing process. Most surgeons still recommend using crutches, but patients are not restricted to a bed or wheelchair as they were previously. Early weight bearing may even contribute to faster bone healing.
OTW was able to recently speak to Stephen Quinnan, M.D., orthopedic surgeon and trauma specialist in Miami, Florida, about his experience with the NuVasive products. He was part of the design team that developed the nail and one of the surgeons who pioneered the balanced cable method, but still found great value in the Precice device.
With over 12 years of experience with external fixation, he has had a very good experience with the internal fixation method from NuVasive. He explained that the internal system offered by NuVasive is ideally suited for patients particularly at risk of infection, concerned with scarring, or have poor quality soft tissue surrounding the defect.
Patients still come for regular monitoring visits, but he finds that he has fewer visits and calls overall for patients with the Precice system. In his experience patients that used external fixation took up to 8 months to heal a defect, and by moving to internal fixation with the balanced cable method, or the Precice nail that time was reduced to 2-3 months depending on the size of the defect. Quinnan acknowledged that the surgical procedure to implant the nails is more technically challenging than using external fixation, but he believes that the benefit to the patient is well worth the training and additional cost of the internal system.
