An Extending Nail to Lengthen Bones

Lengthening the bone is required when a particular bone is not growing at the normal or satisfactory rate and there is a discrepancy between the lengths of the right and left limbs. The reasons for this are usually congenital or developmental (infection, injury, etc.)

When there is a significant difference between the length of the normal limb and that of its opposite, we weigh up the benefits of extension versus the risks. Smaller discrepancies can be balanced (during the growth period) by stopping the lengthening of the normal limb.

Bone-extending mechanisms were based, until recently, on “external stabilizers.” These solutions involved pins or nails inserted into the bone through the soft tissue, supported by an external structure. We make an incision in the short bone – in a place “easy” to extend – and a few days after the incision, we begin to stretch the limb using the external apparatus. A gap is created between the split bone parts and gradually filled with the new bone.

Now though, we use the PRECICE Intramedullary Limb Lengthening System for extending hips, shins and arms. It is operated by an external magnetic system (by the patient, every day). It offers a possible extension of 5-8cm. Inserting the nail is almost transdermal, with small incisions for the nail, the locking screws and for cutting the bone. It is all guided by X-ray screening. It involves 2-3 days in hospital and then the entire treatment is administered at home by the patient, as noted above. 

There are still limitations: the nail is only suitable for children over the age of 8, the extent of the lengthening is limited, it is difficult to repair coronal and sagittal distortion (we can perform a circular repair, but only a small angular repair). The external system is still difficult to program and Generation 3 was released in the summer of 2017. 

Advantages: apart from the obvious (everything is internal, electronic operation, the nail remains in the limb and prevents any breakage in the extension area), there is no permanent equipment or stock in the hospital. The set comes with the nail and an insertion system. The patient hires the operating system from the supplier. It requires short hospitalization and the DRG (Diagnosis-Related Group) is relatively high. 

But the most important thing is that for the patient, this is huge progress. It’s easy, electronic, painless and allows freedom of movement.