Safety and efficacy of Isola instrumentation and arthrodesis for adolescent idiopathic scoliosis: two- to 12-year follow-up.
METHODS
Retrospective case series including patient outcome assessment.


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


BACKGROUND
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.
Asher
Marc
M
Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, KS 66160-7387, USA. masher@kumc.edu
Lai
Sue Min
SM
Burton
Douglas
D
Manna
Barbara
B
Cooper
Andrew
A
D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D020516:Brachial Plexus Neuropathies / Q000209:etiology; D002648:Child; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D005767:Gastrointestinal Diseases / Q000209:etiology; D006801:Humans; D016268:Internal Fixators; D008297:Male; D010523:Peripheral Nervous System Diseases / Q000209:etiology; D011183:Postoperative Complications / Q000453:epidemiology; D011542:Pseudarthrosis / Q000209:etiology / Q000601:surgery; D011859:Radiography; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013478:Superior Mesenteric Artery Syndrome / Q000209:etiology / Q000601:surgery; D013530:Surgical Wound Infection / Q000453:epidemiology; D016896:Treatment Outcome