 |
 |
 |
|
| home | CME | help | feedback | subscriptions | archive |
|
© 1996 The Journal of Bone and Joint Surgery, Inc. Extracorporeal Life Support in the Operative Treatment of Progressive Kyphoscoliosis. A Case Report*   , DALLAS, TEXASInvestigation performed at the Department of Orthopaedics, Texas Scottish Rite Hospital, and Children's Medical Center of Dallas, Dallas
Extracorporeal life support is a method of cardiopulmonary support that is based on modified cardiopulmonary bypass technology. The method is generally indicated when there is a reversible life-threatening lesion in either the cardiac or the pulmonary system. Extracorporeal life support may allow an overworked cardiopulmonary system to rest and mature in the neonatal period or it may provide time for recovery after the operative correction of a severe abnormality. The indications for this procedure and its use have been reported previously1,3,10,11. Extracorporeal life support is a more encompassing term for what has previously been called extracorporeal membrane oxygenation. Blood is pumped outside the body through an oxygenator before it is returned to systemic circulation. We report the use of extracorporeal life support in a child with severe progressive kyphoscoliosis who had pre-existing pulmonary hypoplasia of the left lung because of a congenital diaphragmatic hernia4,6,16. Anterior arthrodesis of the thoracic spine was possible with the intraoperative use of extracorporeal life support. This technique is an option for a select group of patients with severe cardiopulmonary problems who may not otherwise tolerate an intrathoracic operation.
The patient was born at full term with multiple anomalies that included a congenital diaphragmatic hernia on the left, congenital thoracic kyphoscoliosis, and coarctation of the aorta. The congenital diaphragmatic hernia caused respiratory distress on the first day of life, and the patient was managed with extracorporeal life support through cannulation of the right internal jugular vein and internal carotid artery. Reconstruction of the diaphragm was performed, and the patient was weaned from extracorporeal life support at the age of five days5,8,15. A coarctation of the aorta was discovered at that time and was repaired through a left thoracotomy. The left lung was underdeveloped because of the herniation of abdominal contents during the prenatal period, and the patient needed oxygen therapy at home after discharge from the hospital. At the age of eight months, a volvulus developed; it was released and a fundoplication for persistent gastroesophageal reflux was performed. When the patient was eleven months old, he had an inguinal herniorrhaphy bilaterally. By the age of fourteen months, the right kyphoscoliosis, which had measured 30 degrees from the ninth to the twelfth thoracic vertebra when the patient was seven months old, had progressed to 45 degrees. He had a right posterior hemivertebra, which was fused to the inferior portion of the tenth thoracic vertebra, but it was not thought to be the sole cause of the curve (Fig. 1). At that time, a magnetic resonance imaging study ruled out an intraspinal lesion. In an attempt to halt the progression of the curve and to allow for the possible correction of the kyphosis and scoliosis, a posterior spinal arthrodesis of the convex (right) side of the curve, involving an unknown number of levels, was performed. Postoperatively, the treating physician noted increased rotational deformity. An attempt to control the deformity with a thoracolumbrosacral orthosis was unsuccessful.
When he was two years and nine months old, the patient was first seen at our hospital for evaluation of the increasing spinal deformity. He was able to walk and was quite active, but he was chronically dependent on oxygen therapy administered at one liter per minute. On physical examination, he had a pectus excavatum and the left wall of the chest was dysplastic. He had a severe right thoracic kyphoscoliosis. There was no evidence of myelopathy or other neurological abnormalities. The right thoracic scoliosis measured 78 degrees from the fifth to the twelfth thoracic vertebra, and the radiograph of the chest demonstrated marked hypoplasia of the left lung with the left side of the thoracic cage of decreased size6,16. Pulmonary function testing revealed that the forced vital capacity was 36 per cent of the predicted value and the inspiratory capacity was 45 per cent of the predicted value. Two months later, the right thoracic scoliosis measured 90 degrees from the fifth to the twelfth thoracic level and was associated with a kyphosis of 50 degrees, centered at the tenth thoracic hemivertebra. The deformity in the region of the congenital hemivertebra had increased substantially. Because congenital diaphragmatic hernia, pulmonary hypoplasia, and congenital heart disease are known to be associated with progressive scoliosis6,7, we believe that the rapid increase in the number of involved vertebral levels and the magnitude of the curve was due to thoracogenic causes, specifically, pulmonary hypoplasia and the limited development of the thoracic cage. A secondary left lumbar curve measured 65 degrees, and the trunk was shifted three centimeters to the right (Figs. 2-A and 2-B).
The patient was managed with halo traction with fourteen pounds (6.4 kilograms) of weight for six weeks in an attempt to decrease the deformity before arthrodesis was performed. The right thoracic curve measured 65 to 68 degrees in traction and 80 to 85 degrees out of traction. The neurological status remained normal. The pulmonary status was clinically improved in the traction. Given the magnitude and progression of the kyphoscoliosis as well as the skeletal immaturity of the patient, anterior and posterior spinal arthrodesis was believed to be necessary. The goals of the anterior spinal procedure were to perform an anterior release for additional correction as well as anterior strut-grafting of the kyphosis and an arthrodesis to prevent an increase in the deformity due to continued growth of the anterior portion of the vertebra. However, the pulmonary status seemed to preclude a right anterior approach to the thoracic spine. The fact that the preoperative inspiratory capacity was 45 per cent of the predicted value suggested that the patient might need prolonged intubation and ventilatory support after a thoracotomy9. A three-year-old child may not be able to cooperate fully with pulmonary testing, however, and the results should be considered with that caveat13. In this case, extracorporeal life support was chosen as a method to support the patient during an anterior spinal procedure. Before the right thoracotomy was performed, when the patient was three years and four months old, arteriovenous extracorporeal life support was begun, with access through the iliac vessels. This was necessary as the right internal carotid and jugular vessels had been cannulated when the patient was an infant12. An anterior approach to the caudad part of the thoracic spine was performed with excision of the discs and rib-grafting from the seventh to the twelfth thoracic vertebra. He was maintained on extracorporeal life support with the use of a hollow-fiber oxygenator and the Carmeda Bio-Active Surface (Medtronic, Anaheim, California), which was developed in Stockholm, Sweden, for 104 minutes during the right anterior spinal approach and arthrodesis. He received anticoagulation therapy with heparin (total dose, 925 units) during the bypass, with the activated clotting time ranging from 202 to 225 seconds. With the right lung deflated, the oxygen saturation fell to less than 80 per cent when the extracorporeal life-support circuit was clamped. Flow rates of 600 to 820 milliliters per minute were required to maintain appropriate oxygenation. Once the right lung was reinflated, the patient was easily weaned from the extracorporeal life-support system. He was then turned prone, and posterior spinal arthrodesis was performed from the seventh thoracic to the first lumbar vertebra. Instrumentation was not implanted because of the small size of the child. Postoperatively, the patient remained intubated with ventilatory support for three days. He was extubated uneventfully, and the baseline oxygen therapy (one liter per minute) was resumed. For six months postoperatively, the patient was maintained in halo traction at home, with use of a halo-wheelchair and occasionally a halo-walker device. The scoliosis measured 42 degrees after the operation and 60 degrees in traction at the time that the halo was removed. At nine months postoperatively, the correction was maintained at 63 degrees. At the most recent follow-up examination, the patient remained able to walk and no longer had a chronic need for oxygen therapy.
The advances that have been made in perioperative cardiopulmonary support enabled this child with marked pulmonary hypoplasia to have anterior spinal release and arthrodesis at the thoracic level for progressive kyphoscoliosis. The right lung was deflated during the procedure to allow access to the convexity of the deformity. Because of the hypoplastic left lung, a residuum of the congenital diaphragmatic hernia, this patient had extracorporeal life support to oxygenate the blood during the thoracotomy and anterior spinal operation. Extracorporeal life support is a form of cardiopulmonary bypass that allows prolonged support of the heart and lungs. The blood circulates to an oxygenator and is returned to the body with freshly oxygenated hemoglobin. The blood flow is generally established through the internal carotid and jugular vessels as an arteriovenous system. Anticoagulation with heparin is generally necessary, and the activated clotting time is maintained at approximately 250 seconds when a membrane oxygenator is used3. The level of anticoagulation may be reduced by the use of heparin-coated tubing and oxygenating components2,14. This is a particular advantage for orthopaedic patients who have a potential for substantial bleeding. The temporary cardiopulmonary or pulmonary support that can be provided by extracorporeal life support is not curative. Rather, it is a supportive technique that allows intrinsic healing to take place or a corrective procedure to be performed1,10. It is expensive and few orthopaedic patients will need it. However, for patients who have limited pulmonary function and a progressive severe spinal deformity, such as the one described here, this procedure may be life-saving. We believed that an anterior approach to the thoracic spine was indicated for our patient, and extracorporeal life support provided oxygenation during the procedure and could have been used in the postoperative period if standard ventilatory methods had been insufficient.
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
  CiteULike  Connotea  Del.icio.us  Technorati What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Top
Introduction
Case Report
| home | CME | help | feedback | subscriptions | archive | site index |
|
Stanford University Libraries' HighWire Press (TM) assists in the publication of JBJS Online. |