Survivorship analysis of Cotrel-Dubousset instrumentation in idiopathic scoliosis

Repeat surgical interventions following "definitive" instrumentation and fusion for idiopathic scoliosis

STUDY DESIGN

A retrospective chart review was performed on all idiopathic scoliosis patients treated with instrumented spinal fusion over a 15-year period.

OBJECTIVES

To provide an experience from a single institution over a prolonged time period. The goal was to determine the frequency of repeat surgical interventions following the "definitive" spinal fusion surgery and identify the factors responsible for these reoperations.

SUMMARY OF BACKGROUND DATA

Instrumented spinal fusion remains the standard of care in the surgical management of idiopathic scoliosis. This surgery is considered a "definitive" procedure where, barring a complication, no additional surgical procedures are planned. Although many studies have reported the frequency of specific complications following spinal fusion, little information currently exists regarding the cumulative average of these repeat surgical interventions that occur following these "definitive" procedures.

METHODS

Surgical logs were reviewed on all patients who had an instrumented spinal fusion for idiopathic scoliosis from January 1988 through December 2002. All subsequent surgical interventions on these patients were then identified from the logs through December 2004. Pertinent information was gleaned from surgical logs and patient charts to provide details for these reoperations.

RESULTS

A total of 1,046 patients underwent an instrumented spinal fusion for idiopathic scoliosis: 809 had a posterior-only fusion, 228 had an anterior-only fusion, and 9 had a combined anterior/posterior spinal fusion. A total of 172 repeat surgical interventions were performed in 135 patients (12.9%). Of these 135 patients, 29 patients (21.5%) had two or more separate procedures performed. The most common reasons for reoperation were infection, symptomatic implant, and pseudarthrosis. Patients who had posterior fusions had a significantly higher rate of reoperation than patients who had anterior fusions (14.0% vs. 9.3%). Reoperations due to infections and symptomatic implants occurred with significantly higher frequency in the posterior spine fusion group compared with those with anterior spinal fusion. No differences in rates of reoperation for pseudarthrosis were noted between posterior and anterior fusion groups.

CONCLUSIONS

Repeat surgical interventions are relatively common following these supposedly definitive surgical procedures. The most common reasons for return to surgery are infection, symptomatic implant, and pseudarthrosis.

Fusionless surgery for scoliosis: 2-17 year radiographic and clinical follow-up

STUDY DESIGN

Descriptive case series.

OBJECTIVE

To determine whether fusionless, multiple vertebral wedge osteotomy can safely obtain correction of the deformity with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

To our knowledge, no such attempts to manage the AIS with fusionless, vertebral osteotomies have been reported.

METHODS

A total of 20 consecutive patients were treated since 1987. Deformity correction, complications, respiratory function, and patient-oriented outcome were investigated.

RESULTS

There were 20 patients (17 females and 3 males), including 19 with idiopathic and 1 with syringomyelia scoliosis, who underwent surgery at an average age of 16.4 years and were followed for 8.9 years (range 2-17) on average. There were no neurologic complications. One superficial wound infection necessitated debridement. There were 2 patients converted to posterior instrumentation surgery because of deterioration of the deformity. The average Cobb angle of 64.0 degrees before surgery was corrected to 48.2 degrees at 8.9 years after surgery. Decline of the pulmonary function test after surgery was not statistically significant. The patients' responses to questions about function and pain were favorable.

CONCLUSION

Deformity with AIS was safely corrected with fusionless, multiple vertebral wedge osteotomy.

Loss of coronal correction following instrumentation removal in adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective radiographic analysis of patients with adolescent idiopathic scoliosis (AIS) status after instrumentation removal.

OBJECTIVE

To evaluate the effect of instrumentation removal in surgically corrected AIS.

SUMMARY OF BACKGROUND DATA

Spinal instrumentation is occasionally removed for various reasons, most commonly for postoperative pain or infection, in surgically corrected AIS. The fate of instrumentation removal in adults has been previously reported with documented loss of sagittal alignment. However, to our knowledge, the long-term follow-up after instrumentation removal in AIS has not been reported.

METHODS

We retrospectively reviewed the preoperative, pre-instrumentation removal, postoperative following instrumentation removal, and latest follow-up radiographs of all patients with a primary diagnosis of AIS who underwent instrumentation removal after posterior spinal fusion. There were 21 patients (15 females, 6 males) from 2 institutions, at an average age of 14.8 years (range 9-19), who were originally treated between 1988 and 2002. Instrumentation removal occurred at an average of 2.4 years after surgery (range 8 months to 4 years, 2 months), with an average follow-up of 5.2 years (range 2-11). Fifteen patients underwent removal secondary to pain (2 of these with undetected infection) and 6 for known infection. Evaluation included coronal proximal thoracic, main thoracic, thoracolumbar/lumbar (TL/L), and sagittal T2-T5, T5-T12, T2-T12, T10-L2, T12-S1, and sagittal balance before surgery, before instrumentation removal, at immediate post-removal evaluation, and at latest follow-up.

RESULTS

There were 12 main thoracic curves (Lenke type 1), 6 double thoracic curves (Lenke type 2), and 3 double major curves (Lenke type 3) in the series. Average proximal thoracic curve was 19.7 degrees (range 5 degrees -35 degrees ), the main thoracic curve 63.3 (range 42 degrees -112 degrees ), and the TL-L curve averaged 31.4 degrees (range 17 degrees -53 degrees ). There was an immediate loss of approximately 4 degrees (range 0 degrees -8 degrees ) in the main thoracic curve and 6 degrees (range 1 degrees -15 degrees ) in the TL/L curve after removal, with continued settling of an additional 6 degrees (10 degrees total, P = 0.002) in the main thoracic curve, and 3 degrees in the TL/L curve (9 degrees total, P = 0.01). There was also a significant difference in the group that underwent instrumentation removal <2 years after surgery compared to >2 years (main thoracic curve 13 degrees vs. 7 degrees , P = 0.017; TL/L 11 degrees vs. 7 degrees , P = 0.036). There were no significant changes in sagittal curvature or sagittal balance in either group (P > 0.39).

CONCLUSIONS

Instrumentation removal in AIS is not always a benign process because the long-term follow-up of this cohort of patients shows a "settling" effect in the coronal plane of the main thoracic and TL/L curves after instrumentation removal. Interestingly, there was no change in the sagittal plane with time. Parents and patients should be counseled for this result when instrumentation removal is contemplated, and limited removal of focally symptomatic implants should be considered.

Safety and efficacy of Isola instrumentation and arthrodesis for adolescent idiopathic scoliosis: two- to 12-year follow-up

STUDY DESIGN

Retrospective case series including patient outcome assessment.

OBJECTIVE

To study the safety and efficacy of Isola instrumentation in comparison with similar series.

SUMMARY OF BACKGROUND DATA

Both the technique and technology used in the surgical treatment of adolescent idiopathic scoliosis continue to evolve, the common theme since the 1980s being provision of instrumentation stable and strong enough to eliminate the need for postoperative immobilization. The purpose of this study is to determine the safety and efficacy of a system deliberately integrating hook, wire, and screw anchors to deliver torsional and countertorsional corrective loads.

METHODS

A total of 185 consecutive patients, index patient included, were treated by posterior instrumentation and arthrodesis from January 1989 through December 2000. Safety was studied by complications, and reoperation type and occurrence. Effectiveness was studied by deformity correction and health-related quality of life questionnaire response. Variables affecting effectiveness were sought. A total of 179 patients (97%) had outcome assessment at an average of 6 years postoperative, and 176 had radiographic evaluation at an average of 5 years postoperative.

RESULTS

There were no deaths, spinal cord or nerve root problems, or acute posterior wound infections. Proven pseudarthrosis occurred in 4 patients (2.2%) and delayed deep wound infection in 2 patients (1.1%). The implant-related reoperation rate was 8% and was necessary more often in the first quarter of the series (17% vs. 4.6%, P = 0.0062). The largest Cobb angle averaged 62 degrees preoperative and 23 degrees at latest follow-up, 63% correction. The largest angle of trunk inclination averaged 16.7 degrees before surgery and 9.9 degrees at latest follow-up, a 39% correction (P < 0.0001). Eighty-eight percent of patients were satisfied or very satisfied with the outcome. The principal problems identified were the need for a stronger transverse connector, stable end-instrumented vertebrae foundations, and convex thoracic anchorage.

CONCLUSIONS

Isola instrumentation seems to be at least as safe and effective as other instrumentations being used for the surgical treatment of adolescent idiopathic scoliosis.