Radiographic results of arthrodesis with Cotrel-Dubousset instrumentation for the treatment of adolescent idiopathic scoliosis. A five to ten-year follow-up study

Correction of thoracic adolescent idiopathic scoliosis with segmental hooks, rods, and Wisconsin wires posteriorly: it's bad and obsolete, correct?

STUDY DESIGN

Forty-four consecutive thoracic idiopathic adolescent curves surgically treated between 1995 and 1999 at one institution were analyzed. All were thoracic curves; there were no lumbar curves, double major curves, or triple major curves.

OBJECTIVES

To study the clinical and radiographic results for these 44 patients.

SUMMARY OF BACKGROUND DATA

There is currently ongoing discussion regarding the "best treatment" for right thoracic idiopathic scoliosis.

METHODS

Patients were administered preoperative and postoperative Scoliosis Research Society questionnaires. Radiographs were studied for coronal correction, sagittal correction, junctional deformities two segments above/two segments below, fusion status, loss of correction status, complications, and imbalance of curves above and below. Radiographic analysis was by two independent observers. All patients were treated with bilateral 5.5-mm CD Horizon (M-10) instrumentation. Corrective forces were translational and in situ contouring. An average of 10 hooks and 4 Wisconsin wires were used for an average of 14 fixation points per 11 segments. Follow-up was minimum 2 years to maximum 5 years, with an average of 3-year, 10-month follow-up.

RESULTS

All were out of bed on postoperative day 1; none was braced after surgery. The average preoperative thoracic curve was 56 degrees; the average ultimate postoperative curve was 31 degrees (P = 0.0001). In the sagittal plane T5-T12 averaged 22 degrees preoperation and 20 degrees postoperation. For the complete study group (n = 44), the Cobb measurement (P = 0.001) and apical vertebral translation of the lumbar curve (P = 0.001) below improved. For the false double major curve (n = 11) patterns, the unfused lumbar curve averaged preoperation 46 degrees and postoperation 27 degrees (P = 0.0001). There were no neurologic deficits, no wound infections, and no respiratory complications. In regards to the Scoliosis Research Society questionnaires, significant (P < 0.05) changes preoperative to ultimate postoperative were found for questions 3, 5, 11, and 14.

CONCLUSION

"Satisfactory" results were obtained in 44 patients treated with this technique. The complication rate was low and the fusion rate was high. Posterior treatment as described above produces reasonable and dependable results.

Patient and parental perception of adolescent idiopathic scoliosis before and after surgery in comparison with surface and radiographic measurements

STUDY DESIGN

This prospective 2-year follow-up study evaluated patients treated surgically for adolescent idiopathic scoliosis (AIS).

OBJECTIVE

To report parents' perception, patients' perception, and pain and disability before and after surgery and to examine their relationship to anthropometric, back surface, and radiographic measurements.

SUMMARY OF BACKGROUND DATA

No longitudinal studies have examined these factors and their interrelationships.

METHODS

Between 1995 and 1999, 39 AIS patients treated by anterior or posterior USS (Universal Spine System, Stratec, Oberdorf, Switzerland) instrumentation had complete prospective questionnaire, back surface, and radiographic appraisal.

RESULTS

The preoperative Visual Analogue Score (VAS) for pain-predominantly mild backache-was 24 mm (range, 0-78 mm), and the Oswestry Disability Index (ODI) score was 9.2% (0-44.4%). Patients and parents wanted surgery to correct spinal curvature, stop curve progression, and correct the rib-hump (thoracic) and hip and waist asymmetry (thoracolumbar curves). The maximum angle of trunk inclination correlated with VAS and with short-form McGill Pain Questionnaire scores for thoracic curves (P = 0.005, Spearman rank correlation coefficient). Apical vertebral translation correlated with short-form McGill scores and ODI for thoracolumbar curves (P < 0.006, Spearman rank correlation coefficient). Parents rated scoliosis problems more severely than did their children (P < 0.0001, repeated measures of multivariate analysis of variants). There was no change in body image, VAS, ODI, or short-form McGill scores by 2 years' follow-up. Parents and patients perceived scoliosis problems to be less by 2 years' follow-up (P < 0.0005, Wilcoxon matched-pairs signed ranks test). The preoperative surface asymmetry score correlated with the patients' grading of their rib-hump (P = 0.007).

CONCLUSIONS

Back pain incidence was higher than reported for healthy adolescents. Oswestry Disability Index was within normal adult limits. Pain varied by curve type, related to the maximum angle of trunk inclination and the maximum apical vertebral translation. After surgery, back pain and ODI were unchanged, but concerns regarding scoliosis were reduced.

Curve prevalence of a new classification of operative adolescent idiopathic scoliosis: does classification correlate with treatment?

STUDY DESIGN

A retrospective multicenter consecutive case review of operative adolescent idiopathic scoliosis.

OBJECTIVES

To define the curve prevalence of a large consecutive series of cases with operative adolescent idiopathic scoliosis as classified by a new system and to test the ability of this new classification system to correlate with regions of the scoliotic spine to be instrumented/fused.

SUMMARY OF BACKGROUND DATA

A new comprehensive, two-dimensional classification system, intended to be treatment based, has been developed. However, it has not been tested whether all presenting operative cases of adolescent idiopathic scoliosis are classifiable in a large consecutive series, nor has the prevalence of specific curve types been determined. In addition, it is unknown whether this classification is truly treatment based, as to whether it can correlate with regions of the spine to be instrumented/fused.

METHODS

A multicenter retrospective review of 606 consecutive operative cases of adolescent idiopathic scoliosis was performed. All cases were classified by a new triad classification system, which included the following: a curve type (1-6), a lumbar spine modifier (A, B, C), and a sagittal thoracic modifier (-, N, +). Prevalence of the individual three components of the system and the classification grouping of all three components together were performed. In addition, the authors assessed whether this system could correlate with regions of the spine that should be included in the instrumentation and fusion, based on exactly which regions were fused during the operative procedure.

RESULTS

All 606 cases were classifiable by this system. Prevalence of the six curve types noted was as follows: Type 1, main thoracic (n = 305, 51%); Type 2, double thoracic (n = 118, 20%); Type 3, double major (n = 69, 11%); Type 4, triple major (n = 19, 3%); Type 5, thoracolumbar/lumbar (n = 74, 12%); and Type 6, thoracolumbar/lumbar-main thoracic (n = 17, 3%). The five most common curve classifications noted were as follows: 1AN, 1BN, 2AN, 5CN, and 1CN, which accounted for 58% of all curve classifications noted. An average of 90% of the operative cases had surgically structural regions of the spine included in the instrumentation and fusion as predicted by the curve type.

CONCLUSIONS

A new comprehensive classification system for operative adolescent idiopathic scoliosis found all 606 consecutive cases of adolescent idiopathic scoliosis classifiable, with the Type 1, main thoracic curve pattern, the most common curve type found (51%). This new classification system appears to correlate with treatment of surgically structural regions of the spine fused in 90% of cases by the objective radiographic criteria used.

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.

Prospective radiographic and clinical outcomes and complications of single solid rod instrumented anterior spinal fusion in adolescent idiopathic scoliosis

STUDY DESIGN

Prospective clinical cases series.

OBJECTIVES

To prospectively evaluate outcomes and critically review radiographic results and complications associated with single solid rod anterior spinal fusions in adolescent idiopathic scoliosis with 2-year minimum follow-up (range, 2-6 years).

METHODS

Ninety consecutive patients at a single institution with thoracic (n = 43) or thoracolumbar/lumbar (n = 47) adolescent idiopathic scoliosis were treated by one of two surgeons with a similar anterior surgical technique using rib autograft, intradiscal structural (Harms) cages placed below T12, and anterior single solid rod convex compressive instrumentation. The patients were evaluated prospectively with the Scoliosis Research Society outcome instrument and upright radiographs before surgery and minimum 2-year follow-up. RESULTS (RADIOGRAPHIC): The average coronal correction of thoracic curves was from 55 degrees to 29 degrees (47%). The average correction of thoracolumbar/lumbar curves was from 50 degrees to 15 degrees (70%). In the sagittal plane, kyphosis was improved in thoracic fusions from 23 degrees to 30 degrees (T5-T12) and lordosis maintained in thoracolumbar/lumbar fusions at -58 degrees (T12-sacrum). Five patients (5.5%) developed a pseudarthrosis, four with implant failure. Three of five required a posterior fusion for a reoperation rate of 3.3%. The fourth and fifth patients were asymptomatic and appeared fused at the 2-year follow-up, with minimal loss of correction. Common risk factors for pseudarthrosis were smoking (4 of 5), weight >70 kg (4 of 5), and for thoracic pseudarthrosis, hyperkyphosis >40 degrees T5-T12 (2 of 3). RESULTS (CLINICAL OUTCOME): Scoliosis Research Society domain average scores were improved for function, pain, and self-image (P < 0.01). With the Scoliosis Research Society satisfaction domain, 88% responded that they were satisfied with their results and 89% would undergo the same treatment again. Four of five patients with pseudarthrosis did not have statistically significant lower final Scoliosis Research Society scores than those with solid fusions (93 vs. 97, P = 0.18).

CONCLUSION

Anterior instrumented fusions for adolescent idiopathic scoliosis using a single solid rod had good radiographic and clinical outcomes. Consideration should be given to alternate techniques in larger adolescents (>70 kg) with thoracic hyperkyphosis (>40 degrees ), and smoking should be avoided. Poor radiographic outcomes did not correlate with final Scoliosis Research Society scores.

Management of complex pediatric and adolescent spinal deformity

OBJECT

The authors sought to analyze prospectively the outcome of surgery for complex spinal deformity in the pediatric and young adult populations.

METHODS

The authors evaluate all pediatric and adolescent patients undergoing operative correction of complex spinal deformity from December 1997 through July 1999. No patient was lost to follow-up review (average 21.1 months). There were 27 consecutive pediatric and adolescent patients (3-20 years of age) who underwent 32 operations. Diagnoses included scoliosis (18 idiopathic, five nonidiopathic) and four severe kyphoscoliosis. Operative correction and arthrodesis were achieved via 21 posterior approaches (Cotrel-Dubousset-Horizon), seven anterior approaches (Isola or Kaneda Scoliosis System), and two combined approaches. Operative time averaged 358 minutes (range 115-620 minutes). Blood loss averaged 807 ml (range 100-2,000 ml). Levels treated averaged 9.1 (range three-16 levels). There was a 54% average Cobb angle correction (range 6-82%). No case was complicated by the patient's neurological deterioration, loss of somatosensory evoked potential monitoring, cardiopulmonary disease, donor-site complication, or wound breakdown. There was one case of hook failure and one progression of deformity beyond the site of surgical instrumentation that required reoperation. There were 10 minor complications that did not significantly affect patient outcome. No patient received undirected banked blood products. There was a significant improvement in cosmesis, and no patient experienced continued pain postoperatively. All patients have been able to return to their preoperative activities.

CONCLUSIONS

Compared with other major neurosurgical operations, segmental instrumentation for pediatric and adolescent spinal deformity is a safe procedure with minimal morbidity and there is a low risk of needing to use allogeneic blood products.

The low lumbar spine below Cotrel-Dubousset instrumentation: long-term findings

STUDY DESIGN

Retrospective review of long instrumented fusions down to the low lumbar spine for the treatment of adolescent idiopathic scoliosis.

OBJECTIVES

To evaluate whether the use of instrumentation systems that preserve the sagittal profile could reduce the incidence of early degenerative changes.

SUMMARY OF BACKGROUND DATA

Long fusions and distractive Harrington instrumentation in the surgical treatment of adolescent idiopathic scoliosis (AIS) are known to produce pain and degenerative changes in the free lumbar segments. Reports on the use of Cotrel-Dubousett instrumentation (CDI) confirm that the instrumentation maintains physiologic lumbar lordosis, but the evolution of the spine below the fusion is not addressed.

METHOD

Thirty-five patients with AIS and CDI were studied. Their spines were fused to L3 or lower, and they had a minimum follow-up of 10 years. Radiologic measurements were recorded from frontal and lateral radiographs. At the time of last examination, lateral flexion-extension dynamic radiographs and magnetic resonance imaging evaluated the health of the disks below the fusion. Clinical outcome was assessed with the Scoliosis Research Society instrument. A control group consisting of 35 peers without scoliosis served as a reference for the outcome questionnaire.

RESULTS

Surgery kept the sagittal profile in a physiologic range. All but two patients were satisfied with the results of surgery. There were no differences between patients and control group insofar as pain, self-image, general function, and daily activity were concerned. Eleven patients showed instability signs in dynamic radiographs and more than half of patients showed incipient degeneration on magnetic resonance images. These findings are similar to those found in the general population, according to the literature, and could evidence normal aging processes.

CONCLUSIONS

Cotrel-Dubousset instrumentation maintains the physiologic sagittal contour. Although there are some degenerative changes in magnetic resonance images and dynamic radiographs, the quality of life and daily activities of the patients after surgery are similar to those of a normal population of the same age.

The effect of variation in arm position on sagittal spinal alignment

STUDY DESIGN

A prospective radiographic analysis of sagittal alignment in patients with and without previous spinal fusion.

OBJECTIVES

To evaluate the effect of variation of arm position on the segmental, regional, and global sagittal radiographic spinal alignment. In addition, to determine whether spinal fusion has any influence on the effect of variation in arm position on the sagittal spinal alignment.

SUMMARY OF BACKGROUND DATA

Importance of segmental, regional, and global sagittal alignment has been widely promoted. However, no mention has been made of arm positioning during a lateral spinal radiograph and the resultant effects it may have on sagittal alignment and balance.

METHODS

Prospective evaluation of 40 consecutive patients with and 40 consecutive patients without a previous spinal fusion was performed. The patients had lateral long cassette radiographs performed in a standardized fashion with the first radiograph obtained with the patient's arms raised horizontally forward at 90 degrees of flexion at the shoulder, and the second radiograph obtained with arms raised horizontally forward at 30 degrees of flexion at the shoulder. Standard segmental, regional, and global sagittal alignments were measured and statistically compared.

RESULTS

In comparing group 1 (patients with spinal fusion) to group 2 (patients without spinal fusion), there was no statistically significant difference in segmental and regional sagittal alignments. However, positioning the arms at 90 degrees versus 30 degrees resulted in a negative shift of the sagittal vertical axis (SVA) in patients that was statistically significant (P = 0.038) for those with (-6 mm at 90 degrees vs +4 mm at 30 degrees ), but not (P = 0.119) for those patients without (-8 mm at 90 degrees vs -4mm at 30 degrees ) a previous spinal fusion.

CONCLUSIONS

Based on the findings in this study, the authors recommend positioning the arms at 30 degrees of forward flexion from the vertical when obtaining a long cassette lateral radiograph of the entire spine.

Comparison of single- and dual-rod techniques for posterior spinal instrumentation in the treatment of adolescent idiopathic scoliosis

STUDY DESIGN

Two groups of patients undergoing posterior spinal instrumentation and arthrodesis for treatment of adolescent idiopathic scoliosis were reviewed retrospectively.

OBJECTIVE

To compare intraoperative concerns (operative time and blood loss), complications, and outcome in patients undergoing single or double posterior rod instrumentation for treatment of adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

The current treatment of idiopathic scoliosis includes posterior spinal instrumentation and arthrodesis. The standard configuration is a rectangular construct of dual rods connected by cross-links. Use of a single rod with multiple fixation points has been proposed as an alternative method to decrease operative time and blood loss, and to avoid late deep infections.

METHODS

In this study, 21 patients underwent posterior instrumentation using a standard dual-rod construct, and 25 patients underwent posterior instrumentation using a solitary rod with multiple fixation points. Patients were assessed after a minimum 2-year follow-up period.

RESULTS

No significant differences were found in blood loss, operative time, or overall frequency of long-term complications. Although not statistically significant, the trend was toward implant prominence in the double-rod group and implant failure in the single-rod group. Implant failure occurred only in instrumentations extending into the lumbar spine. There was no statistical difference in curve progression.

CONCLUSIONS

Single-rod instrumentation and dual-rod constructs offered similar curve correction, blood loss, and operative time. However, single-rod instrumentation may be more prone to implant failure when extended into the lumbar spine.