A momentous innovation in the surgical treatment of scoliosis was recently reported to our Facebook page. A mother wrote to tell us of her Marfan daughter who became the first patient in Europe to receive anterior vertebral body tethering (VBT), a straightening technique that involves fusionless surgery, thereby ensuring the continuing flexibility of the spine. This significant – universally and personally - operation was performed after much discussion and debate, and the “results have been great”, says mother. Meantime another young girl has since had the same operation. Whilst it may not be for everyone, and has yet to be seen from a long-term perspective, we’re excited about this new surgery. The purpose of this article is to put the new technique in the context of the old - a compare and contrast.
Scoliosis is a “sideways curvature of the spine”. It evolves genetically, or idiopathically – ie without known cause. A curve that emerges at a very young age can sometimes self-correct without treatment and this is known as early onset scoliosis. Curves that are more marked or continue to grow may need more concentrated treatment. Gender-wise, at the younger end, boys are affected slightly more than girls and the curve is often left-sided. Towards the upper end of the age range, the condition is more like adolescent idiopathic scoliosis, the curve is often right-sided and affects more girls than boys.
Knocked sideways by a diagnosis of scoliosis, patients diverge in their approach to treatment, according to the severity of the situation. The mildly affected can take a holistic path, reaping the healing benefits of exercise and external bracing, whilst others require surgical intervention, namely spinal fusion. Put crudely, this classical technique realigns and fuses together the curved vertebrae so that they form a single, solid bone. With the adjacent vertebrae melded together, the deformity is derotated and straightened. Now established as the classical approach this surgical technique has been enhanced over time by modern technology, with correspondingly improved results. Yet - and there’s always a yet – a price must be paid, namely the relative loss of mobility.
Anterior Vertebral Body Tethering Surgery for Idiopathic Scoliosis
Anterior Vertebral Body Tethering (VBT) offers a fusionless treatment option for skeletally immature patients with adolescent idiopathic scoliosis. It utilises patient growth to attain progressive scoliosis correction. The technique uses a braided polyethylene cord anchored to bone screws. The tether is applied to the convex curve at a given tension from low thoracic to high lumbar vertebrae, depending on the type of curve. It is inserted through a thoracoscopic approach.
Clinical follow-up data are sparse, however one-year, two-year, and four-year follow-up results indicate that the curve and rotation are reduced significantly. The complications affect up to 10% of patients and include partial lung collapse and pneumonia. However, no deaths have been reported. A small number return to the operative theatre to relieve the tension to avoid over-correction, at a later date.
These early results indicate that anterior VBT is a safe option for young patients, with minimal major complications. However, long-term follow-up will reveal the true benefits. There is always the option of classical fusion if the new technique does not correct the curve.
Summary prepared by Dr Anne Child for the Marfan Trust