Adolescent idiopathic scoliosis (AIS) treated with arthrodesis and posterior titanium instrumentation: 8 to 12 years follow up without late infection

Abstract

Background: There are no data in the peer-reviewed literature regarding long term results in patients treated for AIS with a posterior titanium instrumentation. Therefore we assessed the outcome in 50 patients treated by titanium implant.

Methods: A total of 50 patients with a mean age of 16.6 years were treated. In all patients, titanium hooks and pedicle screws were used in combination. The demographic data and the pre- and post-operative radiographs of all 50 patients were re-examined, and 49 of the 50 patients (98%) attended a radiological and clinical follow up-examination on average 10.1 years post-operatively. The clinical results were recorded by means of the SRS 24 questionnaire.

Results: In the frontal plane, the mean pre-operative thoracic and lumbar curve had been 62.4 degrees and 43.5 degrees respectively, post-operatively the curves were reduced to 26.9 degrees and 16.3 degrees , resulting in a correction rate of 56.9% for thoracic and 62.5% for lumbar curve. At the follow up-evaluation, the Cobb angle of the thoracic and lumbar curve was 31.0 degrees and 21.3 degrees respectively, giving a final correction rate of 50.3% for thoracic, and 51.0% for lumbar curve. 7 of the 50 patients (14.3%) had undergo revision surgery for complications, but complete implant removal was necessary in only one case. Analysis of the SRS 24 questionnaire showed an average score of 95.8 points.

Conclusion: Posterior titanium instrumentation is a safe and effective procedure in the surgical correction of AIS. In this retrospective study with small patient number, it shows favourable long-term results; in particular, the loss of correction is low, no late infection occurred and there was a very high survival rate of the implant itself.

Figure 1

Instrumentation system WSI Titan, an over the top loading system with screws and hooks.

Figure 2

2A – 2D female patients; 15 years old at time of surgery; Curve: King 2, Instrumentation with titanium implant T5 to L2; SRS 24 questionaire at follow up: 98 of max. 120 points. 2A: Cobb preop: thoracic 61°, lumbal 46°, 2B: Cobb postop: thoracic 34°, lumbal 20° 2C: Cobb 15 months postop: thoracic 34°, lumbal 32° 2D: Cobb 101 months postop: thoracic 34°, lumbal 38°