Extension of fusions to the pelvis in idiopathic scoliosis

STUDY DESIGN

Retrospective study of patients after extension of previous scoliosis fusions to the pelvis.

OBJECTIVE

To determine whether modern instrumentation and surgical techniques provide for increased fusion rates with fewer complications.

SUMMARY OF BACKGROUND DATA

Traditionally, long fusions to the pelvis in adults with idiopathic scoliosis have resulted in high complication rates, including pseudarthrosis.

METHODS

The hospital and clinic charts of 41 patients (40 female, 1 male) were reviewed 41 months (range: 24-116) after surgery for extension to the pelvis of previous scoliosis fusions. Thirty-nine of 41 had a combined anteroposterior fusion extension; two had posterior extension only. In 37 of 41 patients, Cotrel-Dubousset (CD) instrumentation was used; in two, Isola (Acromed Corp., Cleveland, OH), in one, TSRH; (Sofamor-Danek, Memphis, TN), and in one, Synergy (Cross Medical Products, Columbus, OH). Parameters analyzed were fusion rate, sagittal and coronal balance, lumbar lordosis, length of fusion extension, and distal fixation method.

RESULTS

Complications were seen in 30 of 41 patients. The pseudarthrosis rate was 37% (15/41) and was significantly related to the method of distal posterior fixation. With sacral fixation only, the rate was 53% (8/15), with iliac fixation only 42% (3/7), and with both iliac and sacral fixation 21% (4/19; P < 0.05). This was not correlated with fusion rate, and the length of fusion extension did not affect the pseudarthrosis rate or sagittal balance.

CONCLUSION

When fixed to the ilium and sacrum, modern instrumentation appears capable of maintaining sagittal balance with lower rates of pseudarthrosis when previous scoliosis fusions are extended to the pelvis. The complication rate remains significant.

Measurement accuracy in congenital scoliosis

BACKGROUND

The accuracy of measurement of curves in idiopathic scoliosis has been extensively studied; however, we know of only one article in the literature concerning the accuracy of measurement of curves in congenital scoliosis. That article stated that intraobserver variability was +/- 9.6 degrees and interobserver variability was +/- 11.8 degrees.

METHODS

Sixty-nine curves in fifty patients with congenital scoliosis were measured on two separate occasions by seven different observers with varying experience in curve measurement.

RESULTS

Mean intraobserver variance ranged from 1.9 degrees to 5.0 degrees, with an average of 2.8 degrees (95% confidence limit, +/- 3 degrees) for the seven observers. The interobserver variance was 3.35 degrees (95% confidence limit, 7.86 degrees).

CONCLUSIONS

It is possible to measure curves in congenital scoliosis with much greater accuracy than previously reported. In the clinical situation in which a skilled observer can measure two radiographs at the same time, an accuracy of +/- 3 degrees can be expected 95% of the time.

Breast cancer mortality after diagnostic radiography: findings from the U.S. Scoliosis Cohort Study

STUDY DESIGN

A retrospective cohort study was conducted in 5573 female patients with scoliosis who were referred for treatment at 14 orthopedic medical centers in the United States. Patients were less than 20 years of age at diagnosis which occurred between 1912 and 1965.

OBJECTIVES

To evaluate patterns in breast cancer mortality among women with scoliosis, with special emphasis on risk associated with diagnostic radiograph exposures.

SUMMARY OF BACKGROUND DATA

A pilot study of 1030 women with scoliosis revealed a nearly twofold statistically significant increased risk for incident breast cancer. Although based on only 11 cases, findings were consistent with radiation as a causative factor.

METHODS

Medical records were reviewed for information on personal characteristics and scoliosis history. Diagnostic radiograph exposures were tabulated based on review of radiographs, radiology reports in the medical records, radiograph jackets, and radiology log books. Radiation doses were estimated for individual examinations. The mortality rate of the cohort through January 1, 1997, was determined by using state and national vital statistics records and was compared with that of women in the general U. S. population.

RESULTS

Nearly 138,000 radiographic examinations were recorded. The average number of examinations per patient was 24.7 (range, 0-618); mean estimated cumulative radiation dose to the breast was 10.8 cGy (range, 0-170). After excluding patients with missing information, 5466 patients were included in breast cancer mortality analyses. Their mean age at diagnosis was 10.6 years and average length of follow-up was 40.1 years. There were 77 breast cancer deaths observed compared with the 45.6 deaths expected on the basis of U.S. mortality rates (standardized mortality ratio [SMR] = 1.69; 95% confidence interval [CI] = 1.3-2.1). Risk increased significantly with increasing number of radiograph exposures and with cumulative radiation dose. The unadjusted excess relative risk per Gy was 5.4 (95% CI = 1.2-14.1); when analyses were restricted to patients who had undergone at least one radiographic examination, the risk estimate was 2.7 (95% CI = -0. 2-9.3).

CONCLUSIONS

These data suggest that exposure to multiple diagnostic radiographic examinations during childhood and adolescence may increase the risk of breast cancer among women with scoliosis; however, potential confounding between radiation dose and severity of disease and thus with reproductive history may explain some of the increased risk observed.

Postoperative deep wound infection in adults after posterior lumbosacral spine fusion with instrumentation: incidence and management

The authors reviewed 817 instrumented lumbosacral fusions in adults and found an incidence of 3.2% deep wound infections. The primary focus of this study was the management of these infections, with particular attention to whether the implants needed to be removed. A consulting infectious disease specialist indicated that an acute infection of a low back fusion wound could not be healed without removal of the metallic implants. This opinion was in contrast to the authors' daily experience and prompted this study. The authors identified and reviewed 817 cases of instrumented posterior lumbosacral arthrodeses in adults. A detailed analysis of any case with a deep wound infection was performed and yielded and infection rate of 3.2% (26 patients). Of these, 24 achieved a clean, closed wound without removal of instrumentation through a protocol of aggressive debridement and secondary closure. Instrumentation removal is not necessary to obtain a clean, closed wound using an aggressive approach with early diagnosis, vigorous debridement in the operative room under general anesthesia, delayed primary or secondary closure, and appropriate antibiotic coverage.

The spine in diastrophic dysplasia. The surgical arthrodesis of thoracic and lumbar deformities in 21 patients

STUDY DESIGN

Retrospective chart and radiographic film review.

OBJECTIVES

To discern the deformity problems in diastrophic dysplasia and to report our results in surgical treatment.

SUMMARY OF BACKGROUND DATA

Due to the rarity of the problem, the literature is very scanty as to the indications for surgery or the best technique.

METHODS

Analysis of radiographic film for scoliosis, kyphosis, lordosis, and decompensation before surgery, after surgery, and at follow-up. Analysis of charts for complications and problems.

RESULTS

The most common deformity pattern was a double thoracic kyphosis (79 degrees/97 degrees) with a true kyphosis at the junction of the two scolioses (101 degrees). Combined anterior-posterior arthrodesis gave the best results.

CONCLUSIONS

Very severe deformity can occur in children with diastrophic dysplasia, even at a young age. Prompt anterior-posterior arthrodesis can prevent catastrophic deformity.

Complications associated with pedicle screws

BACKGROUND

The safety and the effectiveness of pedicle-screw instrumentation in the spine have been questioned despite its use worldwide to enhance stabilization of the spine. This review was performed to answer questions about the technique of insertion and the nature and etiology of complications directly attributable to the screws.

METHODS

We performed a retrospective review of all of the pedicle-screw procedures that were done by us from January 1, 1984, to December 31, 1993. We inserted 4790 screws during 915 operative procedures on 875 patients; 668 (76.3 percent) of the patients had a lumbosacral arthrodesis. The mean duration of follow-up was three years (range, two to five years). The accuracy of screw placement was assessed on intraoperative, immediate postoperative, and follow-up radiographs with use of a technique that was developed by one of us (F. D.); this technique has yet to be validated to determine the prevalence of various types of error.

RESULTS

Of the 4790 screws, 4548 (94.9 percent) had been inserted within the pedicle and the vertebral body. One hundred and thirty-four (2.8 percent) of the screws had perforated the anterior cortex, and this was the most common type of perforation. One hundred and fifteen (2.4 percent) of the screws were associated with complications that could be ascribed to the use of pedicle screws. The most common problem was late-onset discomfort or pain related to a pseudarthrosis or perhaps to the screws; this problem was associated with 1102 (23.0 percent) of the screws, used in 222 (24.3 percent) of the procedures. The symptoms necessitated removal of the instrumentation with or without repair of the pseudarthrosis. A pseudarthrosis was found during forty-six (20.7 percent) of the 222 procedures. Irritation of a nerve root occurred after nine procedures (1.0 percent) and was caused by eleven screws (0.2 percent); it was more commonly caused by medially placed screws. Three patients had residual neurological weakness despite removal of the screws. Twenty-five screws (0.5 percent), used in twenty procedures (2.2 percent), broke. The screws that broke were of an early design. A pseudarthrosis was found in thirteen of twenty patients who had broken screws. Sixteen of the twenty patients had an exploration; three of them were found to have a solid fusion, and thirteen were found to have a pseudarthrosis. The remaining four patients had evidence of a solid fusion on radiographs and had no pain.

CONCLUSIONS

There are few problems associated with the insertion of screws, provided that the surgeon is experienced and adheres to the principles and details of the operative technique. Our review revealed a low rate of postoperative complications related to pedicle screws. The problem of late-onset pain may be related to the implants or to the stiffness of the construct; however, it is difficult to accurately identify its exact etiology.

Congenital spine deformities: scoliosis, kyphosis, and lordosis

By definition, congenital spine deformities-scoliosis, kyphosis, and lordosis-are due to abnormal vertebral development. Thus, affected children tend to have a curvature noted much earlier in life than typical patients with idiopathic scoliosis. This early development of the deformity has resulted in a tendency for the young child with congenital deformities to receive less than optimal care. These curves must not be allowed to progress. In many cases, early fusion is necessary, which is preferable to allowing severe curves to develop.

A King type II curve pattern treated with selective thoracic fusion: case report with 44-year follow-up

The optimal surgical treatment of the King-Moe type II thoracic curve pattern is controversial. The issue of postoperative "decompensation" has arisen in conjunction with the use of third-generation instrumentation systems. This report presents the 44-year clinical and radiographic follow-up of a patient with a type II scoliosis treated with uninstrumented selective thoracic fusion using the criteria of King and Moe. The caudal extent of the fusion was defined by proper identification of the neutral and stable vertebra. At final follow-up, the patient remained well balanced and essentially pain free. Her level of function was "above average" for her age, as per SF-36 evaluation.

Congenital scoliosis with posterior spinal arthrodesis T2-L3 at age 3 years with 41-year follow-up. A case report

STUDY DESIGN

A case report.

OBJECTIVES

To document the long-term effects of early fusion for progressive congenital scoliosis.

SUMMARY OF BACKGROUND DATA

There is concern about fusion at an early age causing torso shortening and possible crankshaft phenomenon.

METHODS

A review of medical and radiologic records.

RESULTS

A 3-year old girl with progressive congenital scoliosis had posterior spinal arthrodesis in 1955. A pseudarthrosis was repaired at age 4, and at age 8 she had an osteotomy of the fusion mass because of bending of the fusion mass. In a follow-up 41 years after fusion, she has no back pain and no history of pulmonary problems. Despite the long fusion at a young age, her torso-to-leg ratio was remarkably good. The thoracic lordosis had improved to a normal thoracic kyphosis.

CONCLUSION

Early arthrodesis was life saving and caused no long-term problems. Because significant spinal growth has occurred by age 3, no adverse effects on torso-leg ratio with an early long arthrodesis, and in addition the crankshaft phenomenon is rare in congenital scoliosis.

Coronal and sagittal balance in surgically treated adolescent idiopathic scoliosis with the King II curve pattern. A review of 67 consecutive cases having selective thoracic arthrodesis

STUDY DESIGN

A retrospective study by an independent observer of a consecutive series of 67 cases of adolescent idiopathic scoliosis presenting with a King II curve pattern.

OBJECTIVES

To demonstrate the validity of a selective thoracic fusion as a treatment of King II curves with special attention to immediate postoperative and long-term trunk balance in the coronal and sagittal planes.

SUMMARY OF THE BACKGROUND DATA

The literature has been fairly controversial in terms of the recommended treatment of King II curve patterns in adolescent idiopathic scoliosis. The main confusion appears to be whether the thoracic curve alone or both curves should be instrumented and fused.

METHODS

Sixty-seven patients were identified as having had a selective posterior thoracic spine fusion with instrumentation between 1961 and 1994. None of these cases had a fusion of the lumbar spine. Preoperative radiographs were analyzed for determination of the appropriate fusion level using the criteria of the stable and neutral vertebra. Follow-up radiographs were evaluated for balance in the coronal and sagittal planes using the central sacral line on posteroanterior radiograph and the C7 sacral promontory line on lateral film.

RESULTS

At 2-year or greater follow-up, the unfused lumbar curve remained equal to or less than the corrected thoracic curve in 63 patients (94%). No patient required extension of fusion. Frontal plane balance analysis showed that 47 of the 67 patients had the T1 plumb line within 2 cm of the midline for an average decompensation of 8.7 mm. In no patient was the loss of balance greater than 3.8 cm. Sagittal plane balance analysis showed that only one patient had inferior junctional kyphosis greater than 10 degrees. This did not require extension of fusion. There were no cases of superior junctional kyphosis.

CONCLUSIONS

The concept of selective thoracic fusion in the King II curve pattern appears to be valid. These findings suggest that arthrodesis of the lumbar spine can be avoided when this pattern is properly diagnosed and appropriately treated. Proper identification of the stable and neutral vertebra and of the appropriate level of fusion are important to achieve good postoperative balance. Successful preservation of lumbar motion segments is important to long-term satisfactory outcome in adolescent idiopathic scoliosis.

The surgical correction of thoracic and lumbar hyperlordosis deformities

Images

Curve progression in Risser stage 0 or 1 patients after posterior spinal fusion for idiopathic scoliosis

A retrospective review was performed to determine "crankshaft" prevalence in 86 immature patients who underwent posterior spinal fusion for idiopathic scoliosis. Tanner stage, chronologic age, bone age, and epiphyseal status were used as maturity indicators. Overall, 62 (72%) patients progressed < or = 10 degrees, 18 (21%) patients progressed 11-15 degrees, and six (7%) patients progressed > or = 16 degrees in the coronal plane. Tanner I patients with open triradiate cartilage had the highest rate of crankshaft occurrence; nine (75%) of 12 patients progressed >10 degrees (p < 0.05). Fifty-two percent of Tanner I, 26% of Tanner II, 11% of Tanner III, and no Tanner IV patients progressed >10 degrees (p < 0.05). Cobb angle increases of >10 degrees degrees occurred in 54% of patients with open triradiate cartilage (p < 0.05) and in 48% of patients with open capital femoral epiphyses (p < 0.05). Anterior and posterior spinal fusion should be considered in prepubertal (Tanner I) patients with open triradiate cartilage.

Adult spinal deformity and respiratory failure. Surgical results in 35 patients

STUDY DESIGN

Retrospective chart and complementary study review.

OBJECTIVES

To describe the features of adult patients with spinal deformity and respiratory failure and to analyze the results of surgical treatment.

SUMMARY OF BACKGROUND DATA

Many authors have studied the relation between spinal deformities and cardiorespiratory failure, but there exists little information about the benefits of reconstructive surgery in severely compromised patients.

METHODS

The charts and complementary studies of 35 adult patients surgically treated between January 1, 1978, and December 31, 1994, were reviewed. The patients were 18 years old or older (average age, 36 years). They had spinal deformity of any etiology with respiratory insufficiency as evidenced by vital capacity of less than 60% of predictive normal, PaO2 less than 80 mm Hg, or PaCO2 more than 45 mm Hg. All had reconstructive spinal surgery in an attempt to improve their respiratory problem.

RESULTS

Seven patients died within the first postoperative year, and one patient was lost to follow-up at 6 months. The other 27 patients had a mean follow-up time of 72 months. The 34 patients were divided into three groups: good, fair, and poor evolution. The patients in the good evolution group had a better preoperative general condition, had more correction of their deformities, had more improvement in their respiratory function, and had fewer complications than those in the other groups. The patients in the poor evolution group were older, had more cardiac problems, and had less correction at surgery.

CONCLUSION

The results of surgery varied from extremely good to extremely bad. The seven patients who died within the first year had no benefit, but the 27 others did very well, usually gaining significant improvement of their respiratory function. Because the alternative to surgical correction is death, this study shows that, under the right circumstances, correction of spinal deformity and, therefore, correction of respiratory function can be life-saving.

The treatment of progressive kyphoscoliosis in camptomelic dysplasia

STUDY DESIGN

This study evaluated the different forms of treatment of camptomelic dysplasia, a rare form of short-limbed dwarfism.

OBJECTIVES

To determine the most efficacious form of management of spinal deformities in camptomelic dysplasia.

SUMMARY OF BACKGROUND DATA

The literature on treatment of spinal deformities in camptomelic dysplasia is sparse. One report advocates aggressive surgical treatment to prevent curve progression and prevent already compromised respiratory function.

METHODS

Eight patients with camptomelic dysplasia and progressive spinal deformity underwent a retrospective chart and radiographic review by an independent observer. Follow-up averaged 3 years and 9 months.

RESULTS

Five of eight patients initially were treated with bracing and six of eight patients eventually required surgery. Average initial kyphosis was 114 degrees and scoliosis 61 degrees, compared with 99 degrees kyphosis and 52 degrees scoliosis at follow-up. Complications included pseudarthrosis (50%) and neurologic problems (33%).

CONCLUSIONS

The authors advocate anterior/posterior uninstrumented fusion and halo cast immobilization postoperatively to prevent curve progression and avoid the potentially fatal sequelae associated with this disorder.

Magnetic resonance imaging evaluation of the adolescent patient with idiopathic scoliosis before spinal instrumentation and fusion. A prospective, double-blinded study of 140 patients

STUDY DESIGN

This was a prospective, double-blinded study of the magnetic resonance imaging findings in the neural axis of 140 neurologically normal typical adolescents with idiopathic scoliosis who were scheduled for scoliosis surgery.

OBJECTIVE

To detect the prevalence of spinal cord and neural axis abnormalities in this select population.

SUMMARY OF BACKGROUND DATA

No similar study exists, although a few related studies were published.

METHODS

Full-length neural axis magnetic resonance imaging studies were reviewed independently by two radiologists who specialize in the spine.

RESULTS

Only four patients had a definite abnormality-one a small thoracic syrinx and the other three with a Chiari malformation. None of these required neurosurgery. All 140 patients had their scoliosis surgery without necrologic compromise.

CONCLUSION

Routine magnetic resonance imaging evaluation of neurologically normal, typical adolescents with idiopathic scoliosis is not warranted, based on this study.

Complications of anterior spinal surgery in children

The purpose of this study was to document the medical and surgical complications of anterior spine surgery in children and to identify risk factors for complications. A retrospective chart review was conducted of 599 anterior procedures (24 anterior only, 300 staged anterior/posterior, 175 combined anterior/posterior procedures) performed between 1967 and 1991. Major complications occurred in 7.5% of procedures and minor complications in 33%. Risk factors for major complications were age > 14 years, male gender, kyphotic curve type, curve sizes > 100 degrees, vital capacity < 40% of predicted, and use of thoracotomy. Risk factors for minor complications were age > 14 years, curves > 100 degrees, vital capacity < 40% of predicted, and use of a staged procedure. Multivariate analyses of risk factors identified age > 14 years and curves > 100 degrees as the most significant risk factors for major complications and age > 14 years for minor complications. We concluded that anterior spinal surgery can be performed in children with an acceptable level of risk and that referral for surgery before 14 years of age and before the curve size progresses will significantly reduce the risk of complications.

Comparison of the use of supine bending and traction radiographs in the selection of the fusion area in adolescent idiopathic scoliosis

STUDY DESIGN

A study was done to evaluate the use of voluntary supine side bending radiographs and Risser table traction radiographs in adolescent patients undergoing posterior spinal fusion for idiopathic scoliosis.

OBJECTIVES

To compare the usefulness of supine side bending and traction radiographs in assessing curve flexibility and determining fusion levels in patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Supine side bending radiographs have been used in the preoperative evaluation of idiopathic scoliosis to determine curve flexibility and fusion area. Traction films have been used to determine the flexibility of large curves and neuromuscular curves where active side bending is not possible. No study to date has compared the use of these films in patients with adolescent idiopathic scoliosis undergoing surgery.

METHODS

Seventy-five patients with more than a 2-year follow-up period after surgery were included in this study. Preoperative radiographs included a standing posteroanterior and lateral film and both supine maximal voluntary side bending films and a traction film done on a Risser table. A preoperative review of these radiographs was done to determine curve flexibility and fusion levels. At follow-up evaluation, the patients were examined for any evidence of decompensation or "adding-on" of levels.

RESULTS

For curves less than 60 degrees, side bending radiographs showed greater curve correction than traction radiographs, whereas the opposite was true for curves greater than 60 degrees. For King I and II curves, side bending radiographs were superior for determination of lumbar curve flexibility and for distinguishing these two types of curves. On traction radiographs, the stable vertebra was 1.4 vertebral levels higher than on the standing film. When the fusion level was moved proximally because of the traction radiograph, decompensation or "adding-on" commonly occurred.

CONCLUSIONS

Supine bending radiographs are superior to traction radiographs for assessing curve flexibility except for curves more than 60 degrees. The selection of the distal extent of fusion based on the traction radiograph gave a large number of poor results. The selection of fusion levels in adolescent Idiopathic scoliosis is best determined by a combination of standing posteroanterior and lateral radiographs and the supine maximum voluntary bend films.

Paraplegia resulting from vessel ligation

STUDY DESIGN

This is a retrospective review of clinical records for evidence of paraplegia specifically resulting from segmental vessel ligation during anterior spinal surgery.

OBJECTIVES

To determine the precise risk rate, and to potentially identify risk factors.

SUMMARY OF BACKGROUND DATA

Although many authors have alluded to this risk, the exact risk rate and risk factors have never been identified.

METHODS

All patients having an anterior approach involving T1-L3 were reviewed. The two reviewers were not involved in any of the surgeries. The 1197 cases were consecutive from 1967 to 1991.

RESULTS

There were no paralyses.

CONCLUSIONS

There would appear to be virtually no risk to segmental vessel ligation provided: 1) vessel ligation is unilateral, 2) done on the convexity of a scoliosis, 3) ligated at midvertebral body level, and 4) hypotensive anesthesia is avoided. Soft clamping with somatosensory-evoked potential monitoring does not appear justified.

Reconstructive spine surgery in pediatric patients with major loss in vital capacity

Thirty-two pediatric patients with severe restrictive lung disease identified with vital capacities < 40% of predicted, who had undergone major reconstructive spine surgery, were reviewed. There were 18 boys and 14 girls, the mean age was 13 years (range, 7-17), and the mean vital capacity was 31% of predicted (range, 16-39%). Fifty-four procedures were performed, 13 posterior only, one of which was staged, and 19 anterior and posterior procedures, of which 15 were staged and four were sequential. The incidence of pulmonary complications (pneumonia, reintubation, pneumothorax, respiratory arrest, or the need for tracheostomy) was 19% (six patients), and only three patients required tracheostomy. The surgical and perioperative mortality rate was zero. Patients who had a thoracotomy or a thoracoabdominal approach had a significantly higher number of pulmonary complications. The use of preoperative decreased vital capacity as a measure of inoperability excludes the young patient most in need of surgical intervention. With improved preoperative, intraoperative, and postoperative techniques, careful monitoring, and the cooperation of pediatric pulmonologists and intensivists, reconstructive spine surgery can be performed in the pediatric patient with severe decreased vital capacity with very acceptable morbidity and mortality.

The surgical and medical perioperative complications of anterior spinal fusion surgery in the thoracic and lumbar spine in adults. A review of 1223 procedures

STUDY DESIGN

A retrospective review of 1223 thoracic and lumbar anterior spinal fusions was performed from 1969 through 1992.

OBJECTIVES

To document the incidence and specific types of perspective complications related to anterior spinal fusions.

SUMMARY OF BACKGROUND DATA

Despite the increased use of anterior spinal surgery, there has been little documentation of the specific types and frequencies of the complications associated with its use.

METHODS

All Minnesota Spine Center patients age 18 years or older who had anterior spinal fusions between the levels of T1 and S1 from August 1969 to June 1992 were reviewed for the occurrence of perioperative complications. Surgical approach and technique and associated comorbidity was recorded.

RESULTS

The risk of a complication was increased for patients over age 60 years, for women, and for patients with multiple preexisting health problems. Serious complications, such as death (0.3%), paraplegia (0.2%), and deep wound infection (0.6%) were rare. The complication rate for complications that were directly attributed to the anterior spinal surgery was 11.5%.

CONCLUSIONS

Anterior spinal fusion surgery is a safe procedure and can be used with confidence when the nature of a patient's spinal disorder dictates its use. Complications are often approach specific.

Segmental spinal dysgenesis. A disorder different from spinal agenesis

We reviewed the clinical and roentgenographic findings, treatment, and results for seventeen patients (six male and eleven female) who had segmental spinal dysgenesis, a disorder frequently confused with, but distinct from, lumbar and lumbosacral agenesis. The average age at the time of presentation to the Minnesota Spine Center or the Gillette Children's Hospital was two and a half years (range, newborn to twenty-one years), and the average duration of follow-up was eight years (range, five months to twenty-two years). At the time of the diagnosis, eight patients had neurological deficits: seven had a neurogenic bladder and four had weakness of the lower extremities. An average of 2.6 procedures (range, one to five procedures) was needed to obtain a solid fusion. Decompression of the stenotic canal was performed in ten patients, and it was followed by an improvement in neurological function in two of them. A solid fusion of the spine, arrest of the progressive kyphosis, and stabilization of neurological function were obtained in all patients. We recommend early anterior and posterior arthrodesis in patients who have segmental spinal dysgenesis, as the progressive kyphosis that inevitably develops often results in neurological deficits.

Excision of hemivertebrae and wedge resection in the treatment of congenital scoliosis

The results of anterior and posterior excision or wedge resection of a hemivertebra and arthrodesis of the spine were reviewed retrospectively for thirty-seven patients. The degree of correction that was obtained and maintained, the balance and alignment of the trunk, changes in pelvic obliquity, and associated complications were evaluated. The average age at the time of the operation was twelve years (range, six months to forty-two years). The average duration of follow-up was six years (range, two to nineteen years). The resection was at the mid-thoracic level in six patients, at the thoracolumbar level in nine, at the mid-lumbar level in seven, and at the lumbosacral level in seventeen. (Two patients had an excision of a hemivertebra at two levels.) Instrumentation was used in twenty-eight patients. Postoperatively, all patients were managed with a body cast, with a unilateral or bilateral pantaloon extension, for four to six months. The instrumentation allowed early walking and the use of a unilateral rather than a bilateral pantaloon extension. The index curve (the curve containing the hemivertebra) averaged 54 degrees (range, 18 to 132 degrees) preoperatively, 33 degrees (range, 0 to 105 degrees) postoperatively, and 35 degrees (range, 0 to 110 degrees) at the most recent follow-up evaluation. A measurable improvement in balance was achieved and maintained in nineteen patients. Pelvic obliquity did not change appreciably, as it was related primarily to limb-length inequality in this series. Complications included a temporary nerve-root lesion in seven patients, a permanent neurological deficit involving the first sacral nerve root in one patient, a pseudarthrosis in three patients, and a wound infection in three patients. Six patients had extension of the arthrodesis to include additional vertebrae.

Scoliosis secondary to rib resection

The case histories of 11 patients (five adults and six children) who presented with scoliosis after multiple rib resection for several disorders were reviewed. All 11 cases developed scoliosis with the convexity directed toward the side of the rib resection. The natural history of the scoliosis was progressive, and the younger the age at the time of rib resection, the more severe the progression. The rate of progression was greatest during the first 10 years after rib resection. The five patients who presented as adults were treated in several ways, only one requiring spine fusion. However, five of the six children required spine fusion to prevent progression of scoliosis.

The Milwaukee brace for the treatment of adolescent idiopathic scoliosis. A review of one thousand and twenty patients

We reviewed the medical records and roentgenograms of 1020 patients who had been managed for adolescent idiopathic scoliosis, between January 1954 and December 1979, with a Milwaukee brace; we wished to determine whether use of the brace had effectively altered the natural history of the disease. The findings were considered with respect to a previous study of 727 children who had had comparable curves and had not initially been managed with the brace but had been followed for progression of the curve, during the same time-span as that in the current study. Of those 727 patients, 558 (77 percent) had no progression of the curve. The average age of the 1020 patients at the time that treatment with the brace was begun was thirteen and one-half years (range, ten to seventeen years). None of the patients had received any other treatment, and all had been managed only by the physicians participating in this study. In both the current and the earlier series, the outcome was considered a failure if the curve had increased 5 degrees or more; in the patients in the current study, who were managed with the brace, the outcome was also considered a failure if operative intervention had been needed. Of the 1020 patients in the current series, 229 (22 percent) had operative intervention; this rate was higher in the patients who had a curve of more than 30 degrees at the time of bracing and in those who had a Risser sign of 0 or 1. The 791 remaining patients, who were managed with the brace only, had a mild improvement of 1 to 4 degrees at the time that use of the brace was discontinued (the difference being within the margin of error of measurement). With respect to curves of between 20 and 39 degrees, the rate of failure was lower in the current series of patients who had been managed with the brace than in the earlier series of patients who had not been thus managed but had been followed for progression. Progression of the curve was found to be related to the pattern and magnitude of the curve; the age of the patient at the time of presentation; the Risser sign; and, in girls, the menarchal status. We recommend that immature adolescents who have a curve of more than 25 degrees and a Risser sign of 0 be managed with a brace immediately, rather than after progression has been documented.

Deep venous thrombosis and pulmonary embolism after major reconstructive operations on the spine. A prospective analysis of three hundred and seventeen patients

We performed a prospective study of 317 patients in order to determine the prevalence of deep venous thrombosis after reconstructive operations on the spine; 126 of the patients were examined with duplex ultrasound assessments of the lower extremities to ensure that no asymptomatic thrombi were being missed. Thigh-high stockings and sequential pneumatic compression of the lower extremities were used, in all patients, for prophylaxis against venous thrombosis. No antiplatelet agents or anticoagulant medications were administered. There was no evidence of thrombosis on any of the duplex ultrasound studies. Subsequently, venous thrombosis developed and was treated successfully in one of the 126 tested patients and in one of the 191 untested patients, and a fatal pulmonary embolus developed in one of the untested patients. The over-all clinical prevalence of thrombotic complications was 0.9 per cent (three complications in 317 patients). All three of the patients who had clinical evidence of thrombosis had had an anterior lumbar procedure because of a degenerative disorder or trauma; however, we could not prove that this approach or these diagnoses were significant risk factors for thrombosis (p < 0.05). While it is possible that some thrombi may have escaped both clinical and ultrasonic detection, such thrombi apparently were not enough of a danger to warrant the use of intensive prophylactic procedures that are associated with more risk. On the basis of this prospective study, therefore, we think that routine screening for the detection of asymptomatic thrombosis in patients who have had a procedure on the spine is unwarranted.

The Galveston technique using Luque or Cotrel-Dubousset rods

The Galveston technique for pelvic fixation in long fusions to the sacrum in neuromuscular and adult scoliosis is an effective technique to help obtain a solid fusion. With careful technique and accurate rod bending, rod insertion, rod contouring, and wire tightening, excellent fixation is obtained that maximizes the fusion rate.

Analysis of the upper thoracic curve in surgically treated idiopathic scoliosis. A new concept of the double thoracic curve pattern

The authors reviewed 246 idiopathic scoliosis patients with the upper thoracic curve of more than 20 degrees. Group I (138 patients) had positive T1 tilt and a spinal fusion which was extended over both the upper and lower thoracic curve with the diagnosis of double thoracic curve. Group II (43 patients) had positive T1 tilt, but the fusion was limited to the lower thoracic curve. Group III (65 patients) had negative or neutral T1 tilt and the fusion was limited to the lower thoracic curve. The average age at operation was 15.9 years (range, 11.2-35 years) and the average length of follow-up was 4.8 years (range, 2-29.5 years). Positive T1 tilt did not correlate well with left shoulder elevation contrary to previous reports. The upper thoracic curve was more rigid than the lower curve in all groups and the lumbar curve was significantly more flexible than the upper and lower thoracic curves in all groups (P < 0.05). No significant difference in the flexibility of the upper thoracic curve was found between the groups regardless of the direction of T1 tilt. When only the lower curve was fused (groups II and III), progression of the upper thoracic curve was less than 5 degrees, and spontaneous correction of the unfused upper curve occurred in the majority of the cases following the supine bending study. Correction and fusion on the lower curve (groups II and III) aggravated shoulder imbalance of all patients with left shoulder elevation. Based on the findings of this study, the authors proposed that the diagnosis of idiopathic double thoracic patterns should be limited to those patterns which require fusion of both the upper and lower curves. This pattern of idiopathic scoliosis includes double thoracic curves with left shoulder elevation and/or a rigid upper thoracic curve.

Long-term evaluation of adolescents treated operatively for spondylolisthesis. A comparison of in situ arthrodesis only with in situ arthrodesis and reduction followed by immobilization in a cast

The medical records and radiographs of forty-two adolescents (twenty-three male and nineteen female) who had had a posterolateral spinal arthrodesis for spondylolisthesis between 1950 and 1986 were reviewed to assess the long-term outcome of this form of treatment. The average age of the patients at the time of the operation was fourteen years (range, seven years and nine months to seventeen years and eleven months). The duration of the clinical and radiographic follow-up ranged from two years to twenty-seven years and seven months. All patients had an in situ arthrodesis of the involved vertebrae. Eighteen patients had no additional intervention, and twenty-four patients had reduction and application of a cast. Use of the cast led to a decrease in sagittal translation of more than 5 per cent in eighteen patients and a decrease in lumbosacral kyphosis (the slip angle) of more than 5 degrees in fourteen patients. Of the patients who did not have a cast, eight had an increase in sagittal translation of more than 5 per cent and ten had an increase in lumbosacral kyphosis of more than 5 degrees. There were no neurological problems at the time of the initial operation or after the reduction maneuver. At the most recent clinical follow-up examination, thirty-eight patients had no complaints of low-back pain or any restriction of work-related or recreational activities. Persistent low-back pain and pain in the lower extremities limited the activities of the remaining four patients, two of whom had another operation to alleviate these symptoms.

Osteogenesis imperfecta. Radiographic classification, natural history, and treatment of spinal deformities

The natural history of the radiographic changes associated with osteogenesis imperfecta was recorded for sixty-four patients. Detailed clinical data regarding spinal deformities were available for forty-three patients. The patients could be placed in six well defined groups on the basis of a cluster of radiographic changes. The radiographic criteria used to classify patients who had osteogenesis imperfecta included the shape, dimensions, and appearance of the long bones; the presence of a trefoil pelvis and protrusio acetabuli; and the shape of the vertebrae. Patients can be classified more accurately if the dynamic nature of the radiographic changes is appreciated. Patients who had Type-A disease, a mild form of osteogenesis imperfecta, maintained the contours of the vertebrae. Most had straight long bones except for five patients who had mild bowing. Patients who had Type-B disease had bowed long bones with wide cortices. The pelvis had a normal contour. The vertebral bodies were biconcave, and kyphosis and scoliosis developed. Patients who had Type-C disease had thin, bowed long bones, and protrusio acetabuli developed around the age of ten years. Patients who had Type-D disease had the same findings as those who had Type-C disease, with the additional finding of cystic changes around the knee by the age of five years. The physes closed early, and the cysts disappeared around the age of fifteen. Patients who had Type-C or D disease had development of severe spinal deformities. Patients who had Type-E disease were totally dependent functionally, and spinal deformities developed at a very early age. The long bones appeared to have no cortex. Patients who had Type-F disease had complete disruption of the ribs, which was incompatible with survival. The natural history of scoliosis in the patients who had Type-B, C, D, or E disease was one of progression of the curve. Bracing used in the treatment of scoliosis in one patient who had Type-E disease and five patients who had Type-C disease was unsuccessful. Arthrodesis of the spine prevented progression of the spinal deformities in patients who had Type-A disease, but the results of the operation were variable in the remaining types of the disease.

Luque-Galveston procedure for correction and stabilization of neuromuscular scoliosis and pelvic obliquity: a review of 68 patients

Sixty-eight patients with neuromuscular spine deformity were treated by posterior spine fusion with Luque-Galveston instrumentation between 1982 and 1986. The minimum follow-up was 4 years. Diagnoses included cerebral palsy in 34 patients and other neuromuscular diseases in another 34 patients. The average age was 14 years. Twenty patients also had anterior spine fusion without instrumentation. Preoperatively the average scoliosis was 73 degrees and this was corrected to 33 degrees at final follow-up. The subgroup having anterior discectomy and fusion had a more severe scoliosis and pelvic obliquity, but the percent of correction was similar to that of the group with posterior reconstruction only. Twenty-four patients who had an associated significant sagittal plane deformity were corrected to a physiologic curvature. A postoperative thoracolumbosacral orthosis was used in 27 patients, and a molded seating orthosis was used in 18. Although the rate of complications was high (62%), most of them were minor. Instrumentation problems occurred in 14 patients (21%), only 4 of them having broken rods. There were no broken wires. Pseudarthrosis occurred in seven patients (10%). Three patients had minor neurologic deficits, all transient. The "windshield-wiper" sign was defined as any radiolucency of 2 mm or greater. Twenty-six patients had this sign at follow-up, and this group had a higher percentage of complications, but the existence of this sign did not necessarily indicate a problem.

Salvage and reconstructive surgery for spinal deformity using Cotrel-Dubousset instrumentation

Sixty consecutive patients who underwent Cotrel-Dubousset instrumentation as part of their reconstructive surgery (failure of previous surgery) were reviewed. The average follow-up was 3 years (range, 2-4.5 years). There were no deaths or major neurologic problems. Pseudarthrosis occurred in six patients, all of whom had long fusion to the sacrum; all six were successfully repaired. Cotrel-Dubousset instrumentation provides a far superior method of correction of deformity and internal fixation than that available previously.

Factors affecting fusion rate in adult spondylolisthesis

The authors examined factors affecting fusion rate in the surgical treatment of 89 consecutive adult patients with spondylolisthesis. Two factors significantly improved fusion rate: combined anterior and posterior fusion and rigid postoperative immobilization in the cast. In 65 patients with isthmic spondylolisthesis, the fusion rate was raised from 70% when posterior fusion alone was used to 88% when combined anterior and posterior fusion was used. In 20 patients with degenerative spondylolisthesis, frequent use of combined anterior and posterior fusion contributed to a high overall fusion rate of 95%. Among patients with isthmic spondylolisthesis, postoperative cast immobilization resulted in a higher fusion rate of 90% compared with a fusion rate of 63% obtained after brace immobilization.

Long scoliosis fusion to the sacrum in adults with nonparalytic scoliosis. An improved method

The first 17 adults with nonparalytic scoliosis having long fusion to the sacrum treated with the Luque-Galveston technique were reviewed. There were 3 men and 14 women. Their average age at the time of surgery was 47 years and the mean follow-up period was 42 months. There were no neurologic complications and no patient developed significant loss of lumbar lordosis. Fusion occurred in 88% of patients. Two patients developed pseudarthrosis, neither of whom had anterior fusion at the level of pseudarthrosis. The best results occurred in patients who had two-stage procedures, with initial anterior lumbar fusion to the sacrum without instrumentation followed by posterior segmental instrumentation with the Galveston technique of fixation to the pelvis.

Air embolism in spinal surgery

We present two cases of fatal venous air embolism that occurred in previously healthy adolescents during posterior spine fusion and instrumentation for scoliosis. Previously recorded cases in the literature have been rare and only briefly discussed. Air embolism has been a complication noted in the anesthesia and neurosurgical literature, occurring primarily in total hip patients and those patients undergoing neurosurgical procedures in a sitting position. An examination of the pathophysiology of air embolism in posterior spinal procedures would indicate the use of properly placed central lines and end-expiratory CO2 monitoring as the primary modes of detection and treatment considering the potentially fatal risk factors for spinal patients.

Adult idiopathic scoliosis treated with Luque or Harrington rods and sublaminar wiring

We reviewed the results of spinal arthrodesis that was performed, with sublaminar wires that were attached to either double L-shaped Luque rods or to a Harrington rod, in forty-two adults who had idiopathic scoliosis. The minimum length of follow-up was two years; the maximum, five years; and the average, three years. The average scoliosis measured 67 degrees preoperatively, was corrected to 37 degrees at operation, and was 44 degrees at the time of follow-up. The final correction averaged 34 per cent. A single Harrington rod and multiple sublaminar wires were used in thirty-one patients. Eighteen of the thirty-one patients had a posterior arthrodesis only and thirteen, a preliminary anterior arthrodesis followed by a posterior arthrodesis. Eleven patients had instrumentation with double L-shaped Luque rods; six of them had posterior arthrodesis only and five, a preliminary anterior arthrodesis followed by a posterior arthrodesis. One patient had neurological deficit that was related to the operation. Three patients had a pseudarthrosis, which was in the lumbar area in all of them. All three patients had had only a posterior operation. No statistically significant difference in the amount of final correction was demonstrated between the subgroups.

Breast cancer in women with scoliosis exposed to multiple diagnostic x rays

Although exposure to ionizing radiation is a recognized risk factor for breast cancer, the potential hazard from low-dose, fractionated exposures during early breast development has not been thoroughly evaluated. Women with scoliosis represent a valuable population for studying this issue because they are exposed to multiple diagnostic x rays during childhood and adolescence, times when the breast may be highly sensitive to the carcinogenic effects of radiation. A study was conducted of 1,030 women with scoliosis who were seen at four Minneapolis area medical facilities between 1935 and 1965. The average age at diagnosis was 12.3 years; 60% of the women had idiopathic scoliosis. Individual x-ray films were counted and the number per patient ranged from 0 to 618 films (mean, 41.5). On average, the x-ray exposures were given over an 8.7-year period. Ninety percent of the women were located, of whom over 92% responded to a mail questionnaire or telephone interview. The average period of observation was 26 years. Overall, 11 cases of breast cancer were reported, compared with six expected (standardized incidence ratio = 1.82, 90% confidence interval = 1.0-3.0). Excess risk increased with time since exposure and was highest among those followed for more than 30 years (standardized incidence ratio = 2.4). Risk also increased with the number of x rays and with the estimated radiation dose to the breast (mean, 13 rad). These data suggest that frequent exposure to low-level diagnostic radiation during childhood or adolescence may increase the risk of breast cancer.