Multisurgeon assessment of surgical decision-making in adolescent idiopathic scoliosis: curve classification, operative approach, and fusion levels.

STUDY DESIGN: A multisurgeon assessment of curve classification, selection of operative approach, and fusion levels via a case study presentation. OBJECTIVES: To evaluate the ability of a group of scoliosis surgeons, not involved in the development of a new classification system, to accurately choose the corresponding curve classification of adolescent idiopathic scoliosis (AIS) cases and to evaluate the variability in the selection of operative approaches and both proximal and distal fusion levels in accordance with the new classification system in operative adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Recent evaluations using the King method for classifying AIS has shown poor intraobserver and interobserver reliability. A new, comprehensive classification system of AIS has been developed, but the result of a scoliosis surgeon's ability to apply the objective classification is unknown. In the surgical treatment of AIS, there are three choices for the operative approach (anterior, posterior, or both) and multiple choices for the selection of fusion levels. METHODS: During an AIS roundtable discussion at a spinal surgery meeting, 28 scoliosis surgeons were presented seven cases of operative AIS via good quality slides. Standard preoperative radiographs and clinical photographs were presented, and the reviewers were asked to classify the cases by a new classification system, choose their preferred surgical approach, and classify both proximal and distal fusion levels. RESULTS: For the seven cases presented, 84% of the curve types, 86% of lumbar modifiers, and 90% of sagittal thoracic modifiers were classified by the reviewers as described in the new classification. The case study found widely variable operative approaches and fusion levels chosen by the reviewers. There was an average of five different proximal (range, 4-8) and four different distal (range, 3-5) fusion levels chosen by the reviewers for each case. CONCLUSIONS: This case study assessment found a relatively high rate (84-90%) of agreement in curve classification of the individual components of a new classification system of AIS. This suggests the ability of a group of scoliosis surgeons to identify the specific criteria necessary for this new classification system of AIS. In addition, the high variability in selection of both operative approach and fusion levels confirms the current lack of standardized treatment paradigms. This further reinforces the need for a method to critically and objectively evaluate these variable treatments to determine the "best" radiographic and clinical results.

Parents' and patients' preferences and concerns in idiopathic adolescent scoliosis: a cross-sectional preoperative analysis.

STUDY DESIGN: A multicenter cross-sectional study of parents' and patient's concerns and preferences regarding surgery for idiopathic scoliosis. OBJECTIVES: The purpose of this study was to analyze independently both the parents' and patients' assessments of upcoming surgery for idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: No group has recently reported querying patients and their parents regarding expectations, preferences, reasons, and concerns about and for surgical treatment of adolescent idiopathic scoliosis. METHODS: Ninety-one sets of parents and patients were separately asked to complete questionnaires regarding the patients' upcoming idiopathic scoliosis surgery. Patients' ages ranged from 9 to 18 years, and data were collected from four centers and seven surgeons (all active members of the Scoliosis Research Society) from April through December 1998. Thirty-nine questions covered concerns (n = 6), reasons for surgery (n = 14), expectations (n = 9), assessment of life as is (n = 5), and scar preference (n = 5). RESULTS: The greatest concern about the surgery expressed by both parents and patients was neurologic deficit. The least concern for both was location and appearance of the scar. The highest expectation and main reason for having the surgery was to reduce future pain and disability as an adult. Families would be either somewhat or very dissatisfied to spend the rest of life "as is." CONCLUSION: Although parents and patients had similar ratings and concerns, the parents' concerns were higher, and expectations were greater than the patients'.

Late-developing infection in instrumented idiopathic scoliosis.

STUDY DESIGN: This is a retrospective review of all patients requiring either Cotrel-Dubousset or Moss Miami rod removal. All initial spinal instrumentations were for adolescent idiopathic scoliosis from 1985 through 1994. Twenty-two patients who underwent rod removal for late-developing infection constitute the study group. OBJECTIVES: To determine the bacteriology and treatment of patients with late-developing infection after posterior spinal instrumentation for scoliosis. SUMMARY OF BACKGROUND DATA: There have been conflicting reports regarding this entity, some reporting a high percentage of positive cultures and others a low yield. The latter have attributed the entity to fretting corrosion. Much literature describes late appearance of infection with large foreign bodies (implants). Glycocalyx, a membrane that surrounds bacteria adjacent to surgical implants, results in poor antibiotic penetration, poor macrophage action, and difficulty in culturing bacteria. METHODS: One thousand two hundred forty-seven patients who underwent posterior instrumentation from 1985 through 1994 were reviewed. Those requiring implant removal were further studied. Those with late-developing infection (more than 1 year after the initial procedure) were further reviewed. Culture reports, presence of pseudarthrosis, and antibiotic regimen after implant removal were the primary parameters studied. RESULTS: Twenty-two patients (1.7%) experienced development of late infection a mean of 3.1 years after the initial procedure. In specimens from these patients cultured only 72 hours, only 1 of 10 was positive. Of those cultured for 7-10 days (the last 12) 11 were positive, usually for low-virulence skin organisms. After surgery, patients received antibiotics parenterally for 48 hours and orally for 7 days. All wounds were closed primarily. Four patients had pseudarthroses, two underwent revised procedures with titanium implants without signs of infection at more than 2 years' follow-up. CONCLUSIONS: Late-appearing infection with spinal instrumentation can be treated with device removal, primary skin closure, and short-term oral antibiotics. The infections affect soft tissue, not the bone.

Comparison of anterior and posterior instrumentation for correction of adolescent thoracic idiopathic scoliosis.

STUDY DESIGN: This was a prospective study of two cohort groups of patients (one group receiving anterior instrumentation and the other posterior instrumentation) receiving treatment for thoracic idiopathic scoliosis. OBJECTIVE: To present the 2-year postoperative results of a prospective multicenter study comparing the use of anterior instrumentation with that of posterior multisegmented hook instrumentation for the correction of adolescent thoracic idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Despite reports of satisfactory results, problems have been reported with posterior systems, including worsening of the lumbar curve after surgery and failure to correct hypokyphosis. Theoretically, the advantages of anterior instrumentation include prevention of lumbar curve decompensation by shortening the convexity of the thoracic curve. In addition, by removing the disc, better correction of thoracic hypokyphosis could be obtained. METHODS: Seventy-eight patients who underwent an anterior spinal fusion using flexible threaded rods and nuts (Harms-MOSS instrumentation, De Puy-Motech-Acromed, Cleveland, OH) were analyzed and compared with 100 patients who underwent posterior spinal fusion with multisegmented hook systems. Parameters of comparison included coronal and sagittal correction, balance, distal lumbar fusion levels, and complication. All patients had idiopathic thoracic curves of King Types II to V. The average age at surgery was 14 years in each group, the average preoperative curve 57 degrees, and the minimum duration of follow-up for all patients 24 months. All data were collected prospectively and analyzed via Epl into statistical analysis (Centers of Disease Control, Atlanta, GA). RESULTS: Average coronal correction of the main thoracic curve was 58% in the anterior group and 59% in the posterior group (P = 0.92). Analysis of sagittal contour showed that the posterior systems failed to correct a preoperative hypokyphosis (sagittal T5 to T12 less than 20 degrees) in 60% of cases, whereas 81% were normal postoperatively in the anterior group. However, hyperkyphosis (sagittal T5 to T12 greater than 40 degrees) occurred after surgery in 40% of the anterior group when the preoperative kyphosis was greater than 20 degrees. Postoperative coronal balance was equal in both groups. An average of 2.5 (range, 0-6) distal fusion levels were saved using the anterior spinal instrumentation according to the criteria used for determining posterior fusion levels in this study. Selective fusion of the thoracic curve (distal fusion level T11, T12, L1) was performed in 76 of 78 patients (97%) in the anterior group as compared with only 18 of 100 (18%) in the posterior group. Surgically confirmed pseudarthrosis occurred in 4 of 78 patients (5%) in the anterior group and in 1 of 100 patients (1%) in the posterior group (P = 0.10). Loss of correction greater than 10 degrees occurred in 18 of 78 patients (23%) in the anterior group and in 12 of 100 patients (12%) in the posterior group (P = 0.01). Implant breakage occurred in 24 patients (31%) of the anterior group and in only 1 patient (1%) of the posterior group. CONCLUSIONS: 1) Coronal correction and balance were equal in both the anterior and posterior groups, even though the anterior group had the majority of curves (97%) fused short or to L1, whereas only 18% were fused short or to L1 in the posterior group. 2) In the anterior group there was a better correction of sagittal profile in those with a preoperative hypokyphosis less than 20 degrees. However, hyperkyphosis (with a mean of 54 degrees) occurred in 40% of those in the anterior group with a preoperative kyphosis of more than 20 degrees. 3) An average of 2.5 lumbar levels can be saved with anterior fusion and instrumentation according to the criteria used for choosing posterior fusion levels in this study. 4) Using the 3.2-mm flexible rod in this study, loss of correction, pseudarthrosis, and rod breakage were unacceptably highe

Intraobserver and interobserver reliability of the classification of thoracic adolescent idiopathic scoliosis.

The system described by King et al. is the standard method for the classification of thoracic adolescent idiopathic scoliosis. Although it is widely used and referenced, its reliability and reproducibility among scoliosis surgeons are unknown. We used a scoliosis case-presentation format to examine the interobserver and intraobserver reliability of the classification of thoracic adolescent idiopathic scoliosis with the system of King et al. Eight active, current members of the Scoliosis Research Society reviewed twenty-seven full-length radiographs that had been made before operative correction of the scoliotic deformity. On the basis of these images, which included posteroanterior and lateral radiographs made with the patient standing as well as right and left forced-side-bending radiographs made with the patient supine, the reviewers assigned a type to each curve according to the classification system of King et al. Kappa coefficients were used to test statistical reliability. The mean interobserver reliability of the classification was only 64 per cent (range, 54 to 77 per cent) when the responses of seven of the reviewers were compared with those of one of the originators of the classification. The mean kappa coefficient was 0.49 (range, 0.27 to 0.73), which indicates poor reliability. When each reviewer's responses were compared with those of the other reviewers, the reliability was similarly poor (interobserver reliability, 55 per cent [range, 33 to 81 per cent] and mean kappa coefficient, 0.40 [range, 0.21 to 0.63]). Intraobserver reliability was evaluated in a trial in which five reviewers in a group setting were shown the same radiographs in a different order at two different viewings. Comparison of the results at the two viewings revealed a mean intraobserver reliability of 69 per cent (range, 56 to 85 per cent) and a mean kappa coefficient of 0.62 (range, 0.34 to 0.95), which indicates fair reliability. The current method of classification of adolescent idiopathic scoliosis does not appear to have sufficient intraobserver or interobserver reliability among scoliosis surgeons to portray curve types accurately. Thus, it may not help to guide treatment with use of modern spinal fixation methods.

Effect of wide posterior release on correction in adolescent idiopathic scoliosis.

Wide lumbar posterior release, consisting of partial excision of spinous process, excision of interspinous ligament and ligamentum flavum, and excision of facet in plane of facet from both outside and within the spinal canal has been employed to increase coronal correction and improve the production of lumbar lordosis (10). Adolescent idiopathic patients with fusion into the lumbar spine were studied. Pre- and postsurgical coronal and sagittal Cobb measurements as well bending measurements were done. Intraoperative biplanar radiographs were done after positioning, after lumbar rod placement, and finally after wide release and placement of the same rod. Statistical analysis was by paired Student's t-test. Significantly (p < 0.005), improved correction was attained in the coronal plane with release (76% vs. 64%). Total lordosis and instrumented segment lordosis was also significantly (p < 0.025) improved with release (12 degrees vs. 3 degrees). Coronal and sagittal plane correction in the lumbar spine is improved significantly with a wide posterior lumbar release.

A simple method for improving vertebral visualization on a scoliosis series lateral radiograph.

STUDY DESIGN: This technical note describe a method for improving vertebral body visualization on lateral scoliosis radiographs. OBJECTIVE: To improve vertebral column visualization on lateral radiographs. SUMMARY OF BACKGROUND DATA: The different density of the thoracic and abdominal cavities makes complete visualization of the vertebral column difficult on lateral radiographs. METHODS: An inexpensive, simple filter paper method was used to normalize the densities between adjacent body cavity and improve visualization of the vertebral column on a lateral scoliosis series radiograph. RESULTS: Use of a single-exposure, filter paper technique improved simultaneous visualization of the thoracic and lumbar vertebrae, compared with the standard single-exposure unfiltered technique. CONCLUSION: Accurate lateral vertebral visualization allows effective three-dimensional correlation of the sagittal plane deformity concurrent with the coronal plane deformity of scoliosis. Using a single-exposure, filter paper technique improves sagittal plane spinal visualization. Repeat radiographs and patients exposure are reduced by this technique.

Internal thoracoplasty. A new procedure.

STUDY DESIGN: The efficacy of performing a thoracoplasty from within the thoracotomy during anterior surgery for scoliosis was investigated. OBJECTIVES: Patients were prospectively studied to determine the possible complications and morbidity of the procedure, and were compared to a similar group of patients that previously underwent same-day anterior and posterior procedures for scoliosis, but without thoracoplasty. Description of the technique is presented. SUMMARY OF BACKGROUND DATA: The seven study patients had uneventful intra- and post-operative courses. For the posterior procedure (CD instrumentation), only morselized rib graft was used, obviating the need for iliac graft. RESULTS: There was no greater rate or additional types of complications in the study group compared to the control group, except one additional day of thoracotomy tube retention. CONCLUSIONS: When same day anterior and posterior procedures are to be performed for scoliosis, internal thoracoplasty is indicated, as a source of autogenous bone and for cosmesis.

Thoracolumbar osteotomy for postsurgical sagittal imbalance.

A prospective study of 12 patients with sagittal plane imbalance after multiple surgeries for scoliosis is reported. Reconstruction was attempted by posterior thoracolumbar junction osteotomy. Eighty-seven degrees of thoracic kyphosis (ending at L3) was improved to forty-one degrees (ending at T12). Lumbar lordosis was increased from 21 to 30 degrees, beginning at L1 afterward (L3 before). 8.7 cm posterior displacement of the sagittal weight-bearing axis was achieved. No permanent complications ensued. The procedure, without anterior surgery, corrects the deformity at the apical area. Cotrel-Dubousset instrumentation secured correction and fixation.

Spinal fusions to the pelvis augmented by Cotrel-Dubousset instrumentation for neuromuscular scoliosis.

Eighteen patients with spinal deformity secondary to a neuromuscular disorder were treated with posterior fusion using Cotrel-Dubousset instrumentation (CDI) to the pelvis. The mean frontal plane curve was 70 degrees preoperatively and 38 degrees postoperatively. The mean loss of correction was 3 degrees at an average follow-up of 28 months. Pelvic obliquity improved in nine patients from a preoperative mean of 22 degrees to 11 degrees at follow-up. Lumbar lordosis was maintained with preoperative and postoperative means of -36 degrees. Complications included perioperative hardware failure in one case and one late, deep infection. There were no neurologic complications, pseudarthroses, or rod breakage. Posterior spinal fusion with CDI to the pelvis is an effective treatment for patients with neuromuscular scoliosis.

Anterior and posterior spinal fusion. Staged versus same-day surgery.

Seventy-five patients who underwent combined anterior and posterior spinal fusion were compared to evaluate the results and safety of staged vs. continuous anterior and posterior spinal fusion. Thirty-five patients underwent two-stage anterior and posterior spinal fusion. The first stage consisted of anterior release; the second stage, which took place 7-10 days later, consisted of posterior spinal fusion and instrumentation. Forty patients underwent continuous anterior and posterior spinal fusion. This procedure consisted of anterior release followed by immediate posterior spinal fusion and instrumentation. The results show that 1) a continuous procedure is faster than the staged procedure; 2) there is less blood loss; 3) fewer days are spent in the hospital; and 4) better correction of the spinal deformity is achieved. Also, the complications were less frequent and less severe with the continuous procedure. It was concluded that the continuous procedure is safe and efficacious and has several advantages over the staged procedure.

Prevention of the crankshaft phenomenon.

Factors favoring development of the crankshaft phenomenon after posterior spinal fusion include immaturity and large residual deformity. Eight patients at high risk to develop the crankshaft phenomenon underwent periapical anterior growth arrest and fusion before posterior instrumentation and fusion. With follow-up to skeletal maturity, 0% developed crankshaft phenomenon. Anterior growth arrest and fusion before a posterior procedure is recommended in scoliosis patients at high risk to develop the crankshaft phenomenon.

Fusion levels and hook patterns in thoracic scoliosis with Cotrel-Dubousset instrumentation.

This study reports the results of treatment of adolescents with King Types 2, 3, and 4 idiopathic curves using Cotrel-Dubousset instrumentation. Imbalance was seen in Types 2 and 4 curves when distraction direction hook patterns crossing the thoracolumbar junction were employed. Imbalance was not seen when a modified hook pattern employing compressing forces across the thoracolumbar junction was employed. No imbalance was observed in Type 3 curves using the basic right thoracic curve hook pattern. In Type 4 curves, a second modified hook pattern is required to obtain improved correction and balance. The mechanism of production of imbalance is explained by a three dimensional analysis of the deformity and of the forces generated by the Cotrel-Dubousset system.

Cotrel-Dubousset instrumentation in neurofibromatosis spinal problems.

Cotrel-Dubousset (CD) instrumentation has been employed in 12 patients with neurofibromatosis with spinal deformity (ten regular scoliosis, one dysplastic kyphoscoliosis, and one multilevel laminectomy). The follow-up period averaged 33 months. In regular scoliosis frontal correction averaged 69%, axial derotation averaged 33%, and sagittal normalcy was produced without immobilization and without pseudoarthrosis. Successful arthrodesis was obtained in a dysplastic patient after initial failure via anterior concave struts and posterior CD instrumentation with immobilization. Stabilization and fusion of one patient with multiple-level thoracic laminectomy was achieved without immobilization. CD instrumentation is effective in the surgical management of neurofibromatous spinal abnormalities.

Cotrel-Dubousset instrumentation.

Cotrel-Dubousset Instrumentation (CDI) presents a diversified posterior implant system applicable in any situation requiring posterior spinal instrumentation. It acts in the three dimensions of the spine, frontal-sagittal-axial. Correct hook site selection and direction provide spinal balance in three dimensions. The double major idiopathic scoliosis is an appropriate model on which to learn the principles of usage of CDI Results of CDI in a wide variety of spinal pathology have been excellent. There is a learning curve for CDI, hook placement being the most significant. Pitfalls and complications can be avoided.

Composite measurement of scoliosis: a new method of analysis of the deformity.

A method of calculation of biplanar spinal deformity in which the frontal Cobb angle is added to the deviation from normal sagittal alignment is presented. Three equivalent groups of adolescent idiopathic scoliosis treated by different surgical methods are presented. When only the frontal Cobb method of comparison was used, results were similar. When the composite measurement that takes into account sagittal changes was used, the Harrington instrumentation group showed significantly poorer results than the Luque rod and Cotrel-Dubousset rod groups. The composite measurement, considering sagittal alignment, is a significantly more valid method of description of the scoliotic deformity and of comparison of treatment methods.

The Milwaukee brace in idiopathic scoliosis: evaluation of 123 completed cases.

The Milwaukee Brace, as evaluated in 123 completed cases, is effective in controlling and correcting mild to moderate idiopathic scoliotic curves. The factors contributing to more correction include dorsal location, younger patients at onset of treatment, more flexible curves, and most important cooperative patients and parents. Less severe curves also achieved greater correction. Loss of correction after brace discontinuance is negligible, due to the fact that weaning and discontinuance were based on the stability of correction after 24 unbraced hours. Patients cooperative with the wearing and exercise program can expect approximately 25 per cent correction in dorsal curves and 20 per cent correction in lumbar curves. Cosmetic improvement can be expected in the majority of patients. Complications are negligible.