SELECTIVE THORACIC FUSION IN AIS BY USING PEDICLE SCREW CONSTRUCTS (PS): WHICH

FACTORS INFLUENCE SPONTANEOUS LUMBAR CORRECTION ?

Azmi HAMZAOGLU, MD

Cagatay OZTURK, MD

Ahmet ALANAY, MD

Mehmet TEZER, MD

Selhan KARADERELER, MD

Ibrahim ORNEK, MD

Istanbul Spine Center

Florence Nightingale Hospital

Istanbul-TURKEY

INTRODUCTION

Although selective thoracic fusion has been a gold

standart treatment modality for Lenke type 1 curves,

there is controversy and not much information in the

literature about how much correction can safely be

done without causing decompensation by using

powerful PS and the factors which may affect the

behaviour of lumbar curve after the surgery.

To analyse Lenke type 1 curves treated by selective

fusion by using PS and to determine the critical factors

which may have influenced spontaneous correction in

lumbar spine.

Between 1995 and 2008, 128 (116 female and 12 male)

consecutive patients with Lenke type 1 curves who

underwent selective thoracic fusion by using PS

constructs were included.

PURPOSE

PATIENT SAMPLE

METHODS The rule for a safe amount of correction in main

thoracic curve was not to correct more than the

lumbar curve magnitude in the preoperative side

bending x-ray.

All patients had intraoperative under-table 35 inch x-

ray to apply the rule.

Preop, postop and follow-up x-ray images were

evaluated in terms of curve magnitudes and flexibility,

sacral tilt (more than 2°), lower instrumented vertebra

(LIV) and maturity.

RESULTS

Average age at the time of surgery was 15 years (range;

10 to 20) and follow-up was 50.6 (range; 24 to 136)

months.

The fusion stopped at stable vertebra in 81 patients, at

neutral vertebra in 31 patients and stable and neutral

vertebra which were the same in 16 patients.

RESULTS

Average correction rates at final follow-up for thoracic

curve was 79% while it was 68% for lumbar curve.

Spontaneous correction more than 5 degrees in lumbar

spine was observed in 34 (26%) patients while an

increase more than 5 degrees were observed in 13

(10%) patients.

RESULTS

Patients younger than age 14, with LIV being both

stable and neutral, with lumbar flexibility more than

60%, with no sacral tilt, risser sign < 2, and female

patients had more lumbar correction rates but the

differences were not significant (p>0.05).

RESULTS

When 5° change was put as a limit, there was a

tendency for deterioration in lumbar curve in patients

who had sacral tilt (p=0.098).

There was no coronal plane decompensation and

imbalance in any of the patients and no reoperation.

CONCLUSION

Correction rates over 70% can safely be obtained in

main thoracic curves by avoiding correction more

than the magnitude of lumbar curve in convex side

bending x-ray.

Lumbar curve may deteriorate during follow-up in

patients with sacral tilt.  

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