Thoracic Insufficiency Syndrome
VEPTR Expansion Thoracoplasty for Thoracic Insufficiency

Vertical Expandable Prosthetic Titanium Rib (VEPTR) expansion thoracoplasty was recently approved by the Food and Drug Administration for treatment of thoracic insufficiency syndrome in skeletally immature patients. Thoracic insufficiency syndrome (TIS) is usually associated with uncommon three-dimensional deformities of both the spine and rib cage. Several types of VEPTR based expansion thoracoplasties operations can be used for different types of deformities to gain chest volume for growth of the underlying lungs while indirectly correcting the scoliosis without spine fusion. VEPTR surgery is extensive, devices are placed under the scapula (shoulder blade) and are attached to the ribs near the neck and continue down to either the spine, or the ribs near the waist, this helps to stabilize the surgically expanded chest wall constriction (expansion thoracoplasty). To accommodate later growth, the devices are expanded twice a year in outpatient surgery through small incisions. Currently, there are a limited number of institutions offering VEPTR surgery. Your child's spine surgeon can advise whether your child's condition is appropriate for VEPTR treatment and provide referral information, if needed. Some centers are using the VEPTR device as a means to straighten the spine indirectly via the ribs and chest wall.

VEPTR surgery is based on the principle that lung growth and spine and rib cage (the thorax) growth are inter-dependent. The VEPTR is a expandable titanium chest wall implant that is attached to the ribs adjacent to the neck and may either extend down to attach to the lower part of the spine or down to the lower ribs of the rib cage. The type and number of devices needed are based on the particular deformity. The devices are made of titanium because the metal is bio-compatible, light and strong, yet does not interfere with MRI tests.

The first VEPTR expansion thoracoplasty was performed in 1989 to treat rib absence and congenital scoliosis. Other types of VEPTR expansion thoracoplasty procedures have been developed to address additional rare spine and chest wall deformities. An FDA multi-center study of VEPTR was concluded in 2005 and VEPTR is now FDA-approved for the treatment of thoracic insufficiency syndrome in skeletally immature patients (those younger than age 14 years for girls and 16 years for boys) under FDA Humanitarian Device Exemption.

Many serious spine and chest wall deformities have been treated with VEPTR procedures. For children with scoliosis and fused ribs, the fused ribs are cut apart and the constricted chest is lengthened to give room for growth of the underlying lungs, with indirect correction of the scoliosis. Chest wall defects, either from congenital absence of ribs or from chest wall tumor resection, can also be treated with VEPTR devices that are placed like a "picket fence" across the defect. Other severe deformities of the thorax such as severe narrowing or mixed defects of rib absence or rib fusion can also be addressed with VEPTR procedures.

Deformity of the spine and the chest wall may deplete volume available for lung growth. This may become an especially critical issue in the first years of life when the lung growth is very rapid due to addition of new lung cells. Without the symmetrical enlargement of the surrounding thorax with growth in the early years, it is unlikely that the underlying lungs can achieve their full potential growth. Failure to maintain optimal lung function may cause pulmonary health problems later in life. Children more than 5 years old can be tested with pulmonary function tests to determine their lung "vital capacity." Spinal surgery with fusion/instrumentation can correct the deformity of the spine, but at the expense of growth in height of the spine. If done early in life, spinal fusions that span a large portion of the thoracic (chest) spine will halt growth in the thoracic spine with effect on the volume of the chest. VEPTR surgery directly treats the volume depletion problems of the thorax of the growing child with indirect correction of the curve and allows for continued growth of both the spine and rib cage. Future studies are planned to compare VEPTR and growing rod treatments to see which deformities of spine and chest are best treated by each approach.

Treatment

A multi-specialty team, consisting of a pediatric orthopaedist or spine surgeon, a pediatric general surgeon or thoracic surgeon, and a pediatric pulmonologist, is best suited to evaluate your child in consideration for treatment by VEPTR expansion thoracoplasty. Entrance into a VEPTR program is a long-term commitment with both benefits and risks. The treatment strategy includes continued expansion of implanted devices until the child reaches skeletal maturity. If treatment is begun during the infant or toddler years, twice a year outpatient surgery for the expansion of devices may be needed for years afterwards to maintain the correction of the deformity and allow the spine to grow. The initial VEPTR implantation surgery may require an average hospital stay ranging from 10 – 14 days with several days immediately after surgery in the pediatric intensive care unit. Once implanted, the device expansion usually requires only an outpatient procedure, and the amount of post-operative discomfort is minimal. Usually by the afternoon of the day of the expansion surgery, patients are able to engage in play activity. The benefit of the long-term VEPTR treatment is to correct rib cage deformit and allow growth of the deformed spine to contribute volume to the thorax and the underlying lungs. During this long period, there will likely be problems and unexpected surgery. The complications of VEPTR treatment include a slow migration of the upper portion of the devices into the rib where it is attached. This usually does not cause any discomfort in children, and, when discovered on X-ray, the device is re-anchored to the rib during the scheduled expansion surgery. Infection and breakdown of the skin over devices also can occur, but these are treatable with a combination of antibiotics and standard surgical techniques. At the end of the treatment period, most VEPTR patients will probably go on to definitive spinal fusion by the time they become teenagers since maximum thoracic volume growth has been completed, but each case will require individual mutual decisions between family, the patient, and your spinal surgeon.

Treatment Steps

Hospital Referral

Referral to a hospital where there is a VEPTR multi-specialty evaluation team. The team will confirm the presence of thoracic insufficiency syndrome and analyze the three-dimensional deformity of the thorax. The evaluation includes history and physical examination, radiographs of both the spine and rib cage, and a CT scan of the chest and lower spine. CT scanners can be optimally tuned to minimize radiation exposure for pediatric patients. Children age 5 years and older can cooperate with pulmonary function studies to investigate further thoracic insufficiency syndrome. Other medically necessary tests may be added by the surgical team, based on a particular referral diagnosis of the child. In some medical centers, infant pulmonary function studies may also be available.

Once the evaluation is complete, all the specialists will meet to discuss the results from their particular viewpoint, and determine whether the thoracic insufficiency syndrome is the prime cause of the clinical problem, and, if so, how severe is it and whether it is getting worse. The decision to undergo surgery may vary from institution to institution, and each patient will be unique in their specific treatment.

VEPTR surgery may not be the best of course of treatment if other forms of treatment can address the problem equally as well or the VEPTR cannot technically be used (such as with patients without ribs, or whose bones are too weak), or if the skin of the patient is too thin to provide coverage for the implants.

At the time of the initial implant surgery the chest is reconstructed in an operation known as a thoracoplasty with the rib cage reconstructed to obtain the largest, most symmetrical volume possible for the underlying lungs. VEPTR devices are then placed to hold the reconstruction in alignment. X-rays and CT scans are repeated to note device position and correction of deformity. No external bracing is used after surgery. Within two weeks of surgery, most patients are up and moving around.

Follow-up

Your child will usually return within 6 months to have the devices expanded in out-patient surgery. X-rays will be taken before and after surgery. A CT scan may also be taken, but usually no more than once a year to monitor growth of the lungs, unless there is an acute medical concern that requires it. If your child is older than age 5 years, a pulmonary function test might be performed to monitor lung function. It is a simple test, requiring your child to blow into a small tube to study air flow. Your child probably can be discharged as early as the day after the procedure.

Once the devices are fully expanded, they will require a change-out to longer devices so that treatment can continue. This is like an expansion procedure, but may require longer incisions and recovery usually takes several days. Once your child reaches the age of 14 years, it is time to plan the last phase of the VEPTR treatment. For most children, this means a spinal fusion, sometimes with partial removal of the VEPTR devices.

Complications

If your child develops drainage from the wound, fever, and has an increase in pain, there may be an infection. You should notify your surgeon so that evaluation and treatment can be arranged. If you live a long distance from the hospital where the VEPTR procedure was performed, you may be instructed to be seen by your pediatrician or a local spine surgeon. Results of the evaluation would be forwarded to your VEPTR surgeon. Digital photographs of the wound are extremely helpful in these situations and can be e-mailed to your surgeon. Some infections are simple suture reactions, and respond to local wound care. More serious infections require both antibiotics and surgical drainage, and sometimes the device has to be temporarily removed to clear up the infection. The device can be re-implanted at a later date once the infection has resolved. Skin breakdown over the device, called skin slough, can be treated surgically. Slow migration of the devices upward into the ribs of attachment is usually picked up on X-ray's taken right before expansion procedures. Migration of the devices almost always causes no clinical problems and can be reseated during the expansion procedure through another limited incision.