[Growth-preserving instrumentation for early onset scoliosis]

Early onset scoliosis is defined as a spinal deformity originating in the first 10 years of life. Growth-preserving spinal instrumentation has therefore been designed to preserve growth of spine and chest wall and lungs to avoid serious pulmonary complications after early spine fusion. Indications, surgical technique and results of the vertical expandable prosthetic titanium rib (VEPTR) technique, traditional growing rods (TGR), and magnetically controlled growing rods (MCGR) will be described.

Indications for VEPTR are so-called mixed congenital deformities (type 3) associated with vertebral malformations in association with chest wall deformities, especially fused ribs. There are also indications for neuromuscular or syndromic early onset scoliosis with bilateral rib-to-ilium constructs. However, most of those deformities are currently treated with either GR or MCGR in most centers. GR and MCGR are currently the treatment of choice for the majority of early onset scoliosis.

There is no indication for growth-preserving strategies if the patients are mature or there is only little growth remaining. In these cases, final fusion should be performed.

While the VEPTR technique involves an extensive approach with muscular dissections to the thoracic cage including rib osteotomies and thoracotomies, treatment with TGR or MCGR is minimally invasive, only exposing proximal and distal anchor points, leaving most of the spine including the apex undisturbed.

Early mobilization is usually possible after 24-48 h. Braces may have to be prescribed for patients with osteopenia, noncompliance, or a risk to fall.

Since 2005, more than 200 patients were treated with the VEPTR technique, more than 200 patients with the MCGR technique, and about 30 patients with the TGR technique in our department. Complication rates are high with all techniques including the law of diminishing returns, autofusion, bone anchor-related complications like loosening or migration of implants, failure to distract and proximal junctional kyphosis. In our own series of 13 patients below age 3 years, VEPTR proved to be effective for mixed deformities. In other studies, we were able to show that physiological growth with MCGR can be maintained for 2-3 years but spinal growth declines after that period with acceptable complications. Complication rates in most studies are lower with MCGR compared to TGR and VEPTR. Therefore, it is currently the treatment of choice for most early onset scoliosis patients.