00098291

open access

Version of Record

Frontal and sagittal balance analysis of late onset idiopathic scoliosis treated with third generation instrumentation

English (英語)

The Kobe journal of the medical sciences

47(6)

231-253

Kobe University School of Medicine

2001-12

2006-07-15

As scoliotic curve is a rotational deformity, derotation maneuvre was used as thecorrective factor, but recent studies demonstrated spinal imbalance and decompensationproblems in patients treated with this method. This study evaluates 217 late onsetidiopathic scoliosis patients surgically treated with third generation instrumentation(Texas Scotish Rite Hospital System - TSRH) from September 1991 to November 1996with a minimum 2 years follow up. Preoperative and postoperative Cobb angles in thefrontal plane and thoracic kyphosis and lumbar lordosis angles in the sagittal plane aremeasured. The balance was analyzed clinically and radiologically by measurement of thelateral trunk shift (LT), shift of head (SH) and shift of stable vertebra (SS) in vertebralunit (VU). At final follow - up correction loss, infection and other complications weredocumented. Mean age of the patients was 14.8 ± 2.3 and mean follow up period 55.8 ±29.5 months. When all the patients were included, preoperative mean Cobb angles ofmajor curves in the frontal plane was 59.1° ± 20.7°. Major curves that were corrected by34.8 ± 20.5 % in the bending radiograms were achieved by 58.9 ± 19.5 % correctionpostoperatively. At the last control, 7.3° ± 6.4° of correction loss was recorded in majorcurves in the frontal plane. Also postoperative kyphosis angle and lumbar lordosisangles were 31.4° ± 11.6° and 30.6° ± 10.9° respectively. Postoperatively, a statisticallysignificant correction was obtained in LT, SH and SS values. None of the patients hadcomplete balance (SH: 0 VU, SS: 0 VU) preoperatively. Only 39.2 % of the patients hadclinically balanced curves (0 VU < SH < 0.5 VU and 0 VU < SS < 0.5 VU).Postoperatively, 47.9 % of the patients were found to be completely balanced, while43.8 % had a balanced curve. Overall 91.7 % of the patients had a trunk balance aftersurgical intervention. The remaining 8.3 % imbalanced curve rate raised up to 16.6 % atfinal follow up, but the loss of correction rates in SS and SH values were found to beinsignificant. The postoperative 'imbalance' problem was mostly seen in Type II andType IV curves. However, at final follow up, the imbalance problem due toovercorrection which became evident especially by 'shift of head' to opposite side wasseen in all types of curves. It is established that high correction rates can be obtained inscoliotic curves with third - generation instrumentation. No undue effects were observedin the uninstrumented lumbar curves. Thoracic sagittal contours of the hypokyphoticpatients were improved. Use of this instrumentation system causes minimal imbalanceproblems and with proper preoperative planning high correction rates can be achieved.

derotation

紀要論文