A Great Leap Forward in Spine and Limb Lengthening Surgeries

Every year thousands of children undergo limb length and scoliosis correction surgery as a result of congenital growth differentials in limbs or large side to side or (sagittal) curves of the spine.  During scoliosis spine surgery, doctors place long metal rods connected to the spine in an attempt to correct a curvature or to stop the curve from worsening or both. In some cases, the surgeon will wait until the patient is in his/her early teens to be sure most of the growing is completed before a correction is attempted.  In some more severe cases, the rods are placed much earlier in patients and are designed to “grow” in length along with the patient as they mature.

The “grow rods” are mechanical and require an additional procedure each time the rods are to lengthened to keep up with the growing spine.  During this procedure the surgeon will re-open the original surgical site and locate the junction of the telescoping rod.  Locking set screws are loosened and the rod is manually lengthened to again support the spine.  This procedure is done many times over the course of the patient’s treatment until the growing is finished.

As for limb length discrepancies, the surgery is very similar.  In the past, “external fixators” were placed on patients securing the lengthening device to the bone with screws or “pins” that are literally screwed into or drilled through the bone.  In this surgery, the bone is cut in the middle of the shaft and is lengthened over the course of time typically around 1mm per day using the external fixator to pull the bones apart.

Incidentally, this procedure was discovered by a Russian doctor name llizarov during WWII.  While treating wounded soldiers with bone defects he discovered the principals of bone lengthening and honed the process using bicycle rims and spokes as the distracting devices.

As you can imagine, these lengthening procedures cause a great hardship on the patient and the parents.  There are many potential complications including infections and mechanical failure of the distraction devices.   Doctors and medical device companies have long sought a better way and that is where Ellipse Technologies has succeeded.

Ellipse has developed both a spinal rod system and limb lengthening system that is completely internal to the patient.  Their implants include a drive system internal to the rod that is moved using magnets in the rod and an external magnetic field that is created using a handheld device and is activated through the skin to trigger the nail to lengthen.

The devices are implanted using traditional surgical procedures.  However, once implanted the patient typically will not require another surgery to lengthen the spinal rod, and the limb lengthening patients do not have any external devices protruding from the skin.  This is truly breakthrough medicine for both patients and parents.

by Tim Graves