Internal Fixation: Precice Plate
What is the Precice Plate?
The Precice Plate is a new (2020) implantable device for lengthening bones that was especially developed for young children. Dr. John Herzenberg and Dr. Shawn Standard of the International Center for Limb Lengthening were on the design team for NuVasive to develop the Precice Plate. Prior to this, the only implantable lengthening options were intramedullary rods, designed to go into the marrow cavity of long bones. For many younger children, this was impractical. Therefore, it became necessary to design an internal bone lengthening metal plate ideal for pediatric patients and patients with very small stature who need limbs lengthened. The Precice Plate can lengthen bones for a maximum of 3.5 to 4.5 cm (1.4 to 1.8 inches) depending on the size of the plate. Our center is one of the first in the world to offer surgery with this innovative device for limb lengthening.
What are the advantages of the Precice Plate?
Internal lengthening nails are physically too large to use inside the bones of very young children and even in some adults with very small stature who have slender bones. The nails cannot be used in some bones of some children who are still maturing, as they would damage the growth plates that enable children’s bones to naturally grow as they mature. This is especially an issue in the tibia. Young children (under eight years old) who needed limb lengthening due to a congenital condition, an injury or a bone defect could previously only be lengthened with an external fixator, a cumbersome metal scaffolding around the outside of the limb being lengthened. The only other option would be to wait until the children were older and their bones grew large enough to accommodate an internal nail, but that is not always in the best interest of the child. The Precice Plate was designed to be used in children as young as three or four years old.
Internal lengthening with a plate is less invasive and physically and socially disruptive for pediatric patients than the metal scaffolding of external fixators. Patients who are lengthened with internal devices have the added benefits of no danger from pin-site infections and a better cosmetic result than can be achieved with external lengthening. There are also less problems keeping the joints limber with physical therapy when the devices are internal.
How does the Precice Plate work?
The surgeon makes a cut in the bone that is to be lengthened called an osteotomy. The Precice Plate is then mounted with screws on the surface of the bone, avoiding potential damage to the child’s growth plate. Once implanted, the patient or caregiver uses a programmable external remote controller (ERC) that magnetically couples with the Precice Plate through the soft tissues to perform precise micro adjustments a few times per day. The surgeon will prescribe how many separate lengthening sessions need to be done each day and the amount of lengthening for each session. Typically, patients are asked to lengthen the bone 0.75 to 1 mm each day (0.03 to 0.04 inches; there are 25 mm in 1 inch).
For example, a patient could be asked to lengthen 0.25 mm during four different sessions throughout the day, which would result in a total of 1 mm of lengthening each day. Each session with the ERC would take about 2 minutes to lengthen the bone 0.25 mm. Four sessions would take a total of 8 minutes per day.
The ERC is placed on the limb and aligned over the implant. The strong magnets within the ERC couple with the magnetic motor inside the Precice Plate. The ERC’s magnets rotate, creating a magnetic field, which induces the magnet inside the plate mechanism to rotate, providing the power to turn a lengthening screw, which causes the device to distract (telescope). This process is very slow and cannot be felt by the patient. Thus, there is stretch of the newly forming bone, typically at a rate of 0.75-1.0 mm per day (0.03 to 0.04 inches; there are 25 mm in 1 inch). The ERC will stop when the patient has completed the correct amount of lengthening for that session.
Over the course of several months and from the comfort of their own home, the patient follows a custom lengthening schedule to gradually distract the Precice Plate, growing newly formed bone to a targeted length. Once the desired bone length is achieved, the plate can be removed.
What should be done to prepare for surgery?
Please visit our Before Surgery section for detailed information. During the visit with the doctor, ask for our guide to prepare for surgery. When planning for Precice surgery, you should also be aware of the following:
- Schedule any necessary MRI scans before surgery: The patient may not be allowed to have an MRI scan after the Precice Plate is applied. An MRI scan could de-magnetize the Precice Plate, making it unable to lengthen.
- Learn about the precautions that should be taken with the ERC: If any family members have a cardiac pacemaker, the ERC will need to be kept away from them. The magnet in the ERC could affect the functioning of some pacemakers. The magnet in the ERC can also adversely affect items such as credit cards, magnetic room keys and cell phones.
- Prepare for the ERC to be noisy: When the ERC is being used to lengthen, it is loud! Parents may want their children to become familiar with the sound before the surgery.
What happens after Precice Plate surgery?
After the Precice Plate is applied, the patient will generally stay in the hospital for 1 to 2 days, though it is possible to go home on the day of surgery in some cases. Our doctors prefer that the patient stays in the Baltimore area for at least the first 2 weeks after being discharged from the hospital. While using the ERC to lengthen the Precice Plate (called the distraction phase), the patient will need to return to the ICLL for postoperative visits approximately every 10 to 14 days. After the distraction phase of treatment is completed, the consolidation phase starts where the bone solidifies and heals. The patient will need to return to the ICLL or send X-rays every month until the bone is healed.
Physical or occupational therapy is critical during the distraction and consolidation phases of treatment. During therapy, the muscles, tendons and ligaments are stretched in order to ensure that the arm or leg will have full movement after treatment. Our doctors may or may not allow this to be done in the patient’s hometown, since some people need more specialized physical therapy, which is available at our center. If patients require specialized physical therapy, they will need to stay in Baltimore for that period of time. In many cases, we also prescribe special braces/splints. These are generally made for the patient during the week after surgery.
The patient will be allowed toe touch weight bearing or no weight bearing on the leg with the Precice Plate. The doctor will determine how much weight bearing is allowed on the leg based on patient age. If both legs will be lengthened, the patient will need to be in a wheelchair.
Please talk to the surgeon if the patient needs to visit the dentist for routine cleaning or dental surgery during treatment. After the Precice Plate is applied, special antibiotics may be necessary in order to have dental work.
When can the Precice Plate be removed?
Typically, the Precice Plate is removed after one year, but this can vary as the lengthened bone must be fully healed before considering removal. The removal procedure is an outpatient surgery, which means that the patient does not need to stay in the hospital overnight after the removal.
Video: “9-Year-Old Niko Can Run Without Pain Thanks to Baltimore Hospital’s New Limb Lengthening Technology”
This video features the story of our patient Nicolai, the very first child to be treated with the Precice Plate at the International Center for Limb Lengthening.