The LimbplastX Limb Lengthening Surgical Procedure
Limb Lengthening Alternatives
rHGH – Recombinant Human Growth Hormone TreatmentPatients with short stature may have impacts related to psychosocial function, which has led to the use of growth hormone (GH) to augment final adult height. The results of treatment are variable depending on dosing, initial age of treatment, parental height, but overall have been modest with 4 cm average adult height gain with an average of 5 years of treatment. As patients reach skeletal maturity, growth hormone no longer becomes an option for height gain and adolescent and adult patients who feel limited by their height seek out other alternatives. Cost of growth hormone treatment is a large consideration and studies have shown that it equates to $90,000-$100,000 USD per inch of height gain.
Risks of GH treatment include intracranial hypertension, increased intraocular pressure, reduced insulin sensitivity, worsening of existing scoliosis, pancreatitis and potential long-term risks of diabetes and cancers.
Other Limb Lengthening Devices and Treatments• There are currently only 2 FDA approved implants for limb lengthening in the USA.
• Other implants and techniques exist world wide, however some have less reliable outcomes.
Other internal devices have issues with lengthening mechanisms requiring re-operation, in-accurate precision of modulating lengthening and more frequent rates of implant breakage.
Fitbone NailOver the last 3 decades, other fully implantable lengthening nails have been developed. Baumgart and Betz from Germany developed a motorized nail in 1991 (now called Fitbone). The Fitbone (Wittenstein, Igersheim, Germany) is a fully implantable lengthening nail whose mechanism is driven by an internal motor that requires an external transmitter. An antenna comes out of one end of the nail and is implanted subcutaneously. It is powered and controlled by radiofrequency and the lengthening is performed at night when the patient is in bed to mimic natural growth. Data are limited, as there are only 3 studies in the English literature that have reviewed a total of 37 implants, although they report good overall results. The series by Singh and colleagues reported that 3/24 nails in 2 patients required later bone grafting. They also had 2 implants that needed to be removed and exchanged for large diameter implants because the gears in the original nails were not strong enough to achieve distraction. Baumgart and colleagues reported that 2/12 nails had faulty motors that required reoperation and only 1 patient required a later bone graft procedure. The Fitbone is the only motorized nail available.
The Gradual Lengthening Nail: Albizzia / Guichet NailGuichet and Grammont from France, developed a telescopic nail in 1994 using a ratchet mechanism which rotated the 2 segments of the nail through the osteotomy and callus of the distraction gap. The Gradual Lengthening Nail also known as Albizzia (Depuy, Villerbuane, France) was later modified and released as the Betzbone and the Guichet nail for use by its 2 namesakes, respectively. It takes 20 degrees of rotation to move the ratchet one notch. Each notch is 1/15 of a millimeter. Many reports exist of patients suffering from severe pain and discomfort, which limit their ability to independently perform the lengthenings. In some cases, these patients required readmission to the hospital with general anesthesia and closed manipulation. In other reports, 12% of the lengthenings remained incomplete because the patients were simply unable to tolerate the pain of the manipulation.
The Intramedullary Skeletal Kinetic Distractor (ISKD) - REMOVED FROM MARKETUsing the same concept of lengthening by rotation through the callus, Cole developed a double-clutch mechanism to cause distraction. Only 3 to 9 degrees of rotation was required to cause the nail to lengthen. The Intramedullary Skeletal Kinetic Distractor (ISKD) (Orthofix Inc., McKinney, TX) was Food and Drug Administration (FDA) approved in 2001. It was recently removed from the market and is no longer available. As the lengthening was so easy to activate, and as there was no “governor” to the lengthening mechanism, the nail is free to lengthen at any rate. Too rapid distraction was a frequent complication. This was referred to as a “runaway nail” or “runaway lengthening.” Due to the uncontrolled lengthening rate and rhythm the ISKD had a very high complication rate. The nail would often lengthen at a rate that exceeded the ability for distraction osteogenesis of bone and histogenesis of soft tissues leading to many complications. Restriction of activities and bracing were required to try and prevent and control too rapid lengthening. Failure of bone formation required separate bone grafting procedure for deficient regenerate.
External-FixatorsExternal-fixators are fraught with complications including:
• pin-tract infections
• associated risk of deep infection
• neurovascular injuries
• prolonged treatment time until removal
• muscular and soft-tissue transfixation that lead to contractures and stiffness
• pain and discomfort
• refracture after removal of the fixators
• psychosocial burden
• requirement to perform daily pin cleaning
• physical awkwardness