Spinal Fusion For Idiopathic Scoliosis Research Articles

Efficacy and cost considerations of intraoperative autologous transfusion in spinal fusion for idiopathic scoliosis with predeposited blood.

One hundred five patients with adolescent idiopathic scoliosis who underwent posterior spinal instrumentation and fusion with predeposited autologous blood, with or without intraoperative autologous transfusion, were reviewed. To determine the benefit/nonbenefit of intraoperative autologous transfusion in diminishing the need for homologous blood and influencing post-operative hematocrit values in healthy adolescents undergoing spinal fusion for scoliosis. A steady increase in the use of intraoperative autologous transfusion in recent years has occurred without guidelines regarding which procedures and patient populations would be best served. Previous studies have failed to determine the cost effectiveness and actual reduction in homologous blood exposure attributable to intraoperative autologous transfusion in adolescents who have undergone preoperative phlebotomy. Fifty-five adolescents (intraoperative autologous transfusion group) who underwent posterior instrumentation and fusion for idiopathic scoliosis with the use of an intraoperative autologous transfusion device were compared to 50 patients (control group) who underwent the same procedure without the intraoperative autologous transfusion device. The average percent salvage of red blood cells by the intraoperative autologous transfusion device was 35%. The control group utilized significantly more of the predonated autologous blood than the intraoperative autologous transfusion group (1.34 units/case vs. 1.78 units/case, P < 0.05). Homologous blood usage was the same in both groups. Two patients in the intraoperative autologous transfusion group required nondirected homologous blood (total of four units), compared to three patients in the control group (total of four units) (P = 0.048). Using multiple regression analysis, the total number of transfusions was significantly correlated with the estimated blood loss and the duration of surgery in both groups. Postoperative hematocrit levels were slightly higher in the control group, but there was not a significant difference. The addition of intraoperative autologous transfusion to a preoperative phlebotomy program had no benefit on homologous blood exposure or post-operative hematocrit changes in this population. Blood requirements for this procedure can be met less expensively and more reliably by merely donating one's own blood.

Intrathecal opioids for hypotensive anaesthesia in children during posterior spinal fusion

Intra-operative bleeding during spinal fusion is a serious problem. Factors influencing the amount of blood loss include extent of dissection, numbers of vertebrae fused, decortication, surgical technique and length of surgery. Hypotensive anaesthesia and haemodilution have been used to decrease blood loss during spinal fusion surgery. Two homogenous groups with 40 patients each (ASA I or II) undergoing posterior spinal fusion for idiopathic scoliosis were compared prospectively. After the induction of anaesthesia, group A received 20 μg kg−1 of morphine mixed with 50 μg of sufentanil diluted with 2 cc of normal saline intrathecally. Group B had standard anaesthesia with inhalation and narcotic technique. Intra-operative blood loss was determined by weighing sponges, measuring suction drainage, and estimating the amount of blood loss in the surgical field. Blood pressure was monitored continuously with an intra-arterial line. Group A had considerably less blood loss than group B (27.5% of blood volume vs. 53.5% in group B; P<0.001). Data regarding age, surgical procedure, weight, and sex were similar in both groups. Use of intrathecal opioids resulted in significantly reduced blood pressures in group A (mean 50-55 mmHg). Lower blood pressures were probably a result of the local-anaesthesia-type action of opioid drugs on the autonomic system [1] causing reduced vascular resistance. The mean arterial pressure (MAP) in group B ranged from 60-70 mmHg. Haemodynamic responses were less variable in group A, with fewer MAPs above 55 mmHg. Mean blood loss was 911.37 mL in group A and 1897.79 mL in group B. This study supports the concept that reduction in arterial blood pressure could be due to the localanaesthesia-type effect of intrathecal opioids. Studies have shown that the compound action potential of isolated nerve preparations can be blocked when exposed to high concentration of fentanyl or sufentanil [2]. In this study blockade of A and C fibres seemed to be concentration-dependent. In conclusion, we feel that intrathecal opioids are a safe choice for producing hypotensive anaesthesia to reduce blood loss and the number of homologous transfusions during spinal fusion surgery.

Vertebral growth after posterior spinal fusion for idiopathic scoliosis in skeletally immature adolescents. The effect of growth on spinal deformity

We studied 29 girls and one boy with adolescent idiopathic scoliosis who were at Risser grade 0 at the time of posterior spinal fusion and were followed until maturity (mean 7.8 years). We used serial radiographs to measure the ratio of disc to vertebral height in the fused segments and to detect differential anterior spinal growth and assess its effect on scoliosis, vertebral rotation, kyphosis, and rib-vertebral-angle difference (RVAD). From one year after surgery to the latest review, the percentage anterior disc height decreased by nearly one-half and the percentage posterior disc height by nearly one-third in the fused segments (p < 0.001). There was a 4 degree increase in mean Cobb angle (p < 0.001), 11 patients (37%) having an increase of between 6 degrees and 10 degrees. There was a significant increase in mean apical rotation by 2 degrees (p = 0.003), and four patients (13%) had an increase of between 6 degrees and 16 degrees. There was little change in kyphosis. There was an increase in mean RVAD by 4 degrees (p = 0.003), seven patients (23%) showing a reduction by 1 degree to 7 degrees, and 11 (37%) increases of between 6 degrees and 16 degrees. Spinal growth occurs after posterior fusion in adolescents who are skeletally immature, as a result of continued anterior vertebral growth. There is some progression of scoliosis, vertebral rotation, and RVAD, but little change in kyphosis. The increase in deformity is not enough to warrant the use of combined anterior and posterior fusion. The findings are relevant to the management of progressive curves, the timing and extent of surgery, and the prognosis for progression of deformity in this group of patients.

The Cotrel-Dubousset System—Results in Spinal Reconstruction

Forty-seven patients were treated with spinal fusion and Cotrel-Dubousset instrumentation and were followed for an average of 28 months. Spinal procedures included: 1) posterior spinal fusion for idiopathic scoliosis (26 patients); 2) posterior pseudarthrosis repair (5 patients); 3) combined anterior/posterior fusion to the sacrum (6 patients); and 4) combined anterior/posterior osteotomies (10 patients). Group 1: Partial derotational correction was achieved for adolescent idiopathic scoliosis. Group 2: Successful pseudarthrosis repair was achieved in four patients. Group 3: A solid arthrodesis was obtained in two patients, whereas the other three patients underwent revision of sacral screw fixation for pseudarthrosis. One patient died postoperatively. Group 4: Pain relief and a balanced correction was achieved in all patients. The Cotrel-Dubousset system appears to be a versatile system and provides a wide range of possibilities for a variety of spinal problems.

Analysis of Lumbar Lordosis in Posterior Spine Fusions for Idiopathic Scoliosis

Previous reports are inconclusive regarding changes in the lumbar region after Harrington rod distraction and posterior spinal fusion for idiopathic scoliosis. The purpose of this study was to evaluate the effects of spinal fusion on the lumbar region, particularly the overall lumbar lordosis, the lumbar lordosis in and below the fused segment, the sacro-horizontal angle, and the sagittal plane alignment of the spine. Sixty-six patients under 21 years of age with idiopathic scoliosis who had spine fusion extending to the lumbar vertebrae using only Harrington distraction instrumentation were evaluated. The total lordosis, sacro-horizontal angle, and sagittal plane alignment remained relatively constant. The lordosis within the fusion decreased, and lordosis caudal to the fusion, including the last fused vertebra, increased as the lower hook placement site moved caudally.

Radicular Pain After Harrington Instrumentation

Three patients developed lumbar radicular pain after Harrington instrumentation and posterior spinal fusion for idiopathic scoliosis. They required a second surgical procedure for nerve root decompression. The presenting complaint after the initial procedure was persistent radicular and buttock pain. Subsequent evaluation revealed direct compression by the inferior hook. At surgery the inferior hook was noted to be encased in bone and had imploded into the canal after a stress fracture of the lamina. Removal of the entire Harrington instrumentation resulted in effective relief of nerve root compression and resolution of radicular pain. To avoid this occurrence the addition of a leg extension to a postoperative brace has been instituted for procedures involving instrumentation to L5 and occasionally to L4.

The effect on the lumbosacral spine of long spinal fusion for idiopathic scoliosis. A minimum 10-year follow-up.

The effect on the lumbosacral spine of long spinal fusion in adolescent idiopathic scoliosis was studied in 22 patients. The average duration of follow-up was 12.8 years. Corrections of the coronal curves through instrumentation were satisfactory. However, a kyphosis was produced at the fused segment of the lumbar spine in more than half of the cases. The unfused intervertebral spaces distally were hypermobile in extension, which probably indicated early disc degeneration. The incidences of back pain and radiological degeneration were found to be low. There was no relationship between back symptoms and type of employment, pregnancies or radiological degeneration. Preservation of normal lumbar lordosis during spinal fusions was emphasized.

The syndrome of inappropriate antidiuretic-hormone secretion following spinal fusion.

Ten adolescent and preadolescent patients who underwent posterior spinal fusion for idiopathic scoliosis or spondylolisthesis were examined for the presence or absence of the postoperative syndrome of inappropriate antidiuretic-hormone secretion. For each patient, levels of serum sodium, serum osmolality, urine sodium, urine osmolality, and serum antidiuretic hormone were obtained preoperatively and postoperatively. The investigation clearly showed that the syndrome occurred in each patient, with the level of serum antidiuretic hormone being highest within a few hours postoperatively. This resulted in a reduction of urinary output, the reduction being maximum on the day of operation and the output gradually rising to normal over the next three days. This syndrome and its associated low postoperative urinary output is common after spinal fusion and should be treated with restriction of fluids rather than administration of increased amounts of fluid.

Improved postoperative course following modified segmental instrumentation and posterior spinal fusion for idiopathic scoliosis.

Postoperative course following posterior spinal fusion was reviewed and compared for 31 patients who underwent Harrington distraction instrumentation and 30 patients who underwent modified segmental spinal instrumentation (SSI). The SSI patients, on average, received oral feedings 1 day earlier (p less than 0.046), walked 5 days earlier (p less than 0.001), and were discharged 5 days sooner (p less than 0.001) than patients undergoing Harrington distraction. Despite this more active postoperative course, the SSI patients did not require more analgesics or narcotics. When the hospital costs were compared, there was a savings of $2,825 for the average patient undergoing SSI.

THE PROGRESSION OF IDIOPATHIC SCOLIOSIS AFTER REMOVAL OF HARRINGTON INSTRUMENTATION FOLLOWING SPINAL FUSION

We have investigated the affect of removal of Harrington rods in 36 patients who had undergone successful spinal fusion for idiopathic scoliosis. In the curves in which further deterioration had taken place even though fusion had been achieved, there was a small improvement in both major and minor curves in the first six months after removal of the rod, followed by complete stabilisation of the curve. A similar tendency to stabilisation was noticed in the curves which had not shown deterioration. We conclude that regression of a curve which has fused following Harrington rod instrumentation occurs when the rod has not been placed according to optimum biomechanical principles. Removal of the rod then relieves the deforming stresses and allows the spine to stabilise.

The progression of idiopathic scoliosis after removal of Harrington instrumentation following spinal fusion.

We have investigated the affect of removal of Harrington rods in 36 patients who had undergone successful spinal fusion for idiopathic scoliosis. In the curves in which further deterioration had taken place even though fusion had been achieved, there was a small improvement in both major and minor curves in the first six months after removal of the rod, followed by complete stabilisation of the curve. A similar tendency to stabilisation was noticed in the curves which had not shown deterioration. We conclude that regression of a curve which has fused following Harrington rod instrumentation occurs when the rod has not been placed according to optimum biomechanical principles. Removal of the rod then relieves the deforming stresses and allows the spine to stabilise.

Fatal Fat Embolism After Spinal Fusion for Scoliosis

An adolescent girl who underwent Harrington instrumentation and spinal fusion for idiopathic scoliosis had the adult respiratory distress syndrome develop in the immediate postoperative period. Massive fat embolization to the lungs was present at postmortem examination, an apparently rare complication of this surgical procedure. This case emphasizes the necessity of maintaining a high index of suspicion. In any clinical setting that would place a patient at risk for fat emboli and illustrates the unreliability of many of the clinical and laboratory features frequently described as useful for establishing the diagnosis.