[Pulmonary function changes after operation in patients with severe scoliosis].

OBJECTIVE

To evaluate pulmonary function changes in patients with severe scoliosis undergoing anterior release, posterior segmental fixation and fusion, and convex thoracoplasty by resecting a short length of rib.

METHODS

From January 2006 to July 2007, 16 patients with severe scoliosis were treated with anterior release, posterior segmental fixation and fusion, and convex thoracoplasty by resecting a short length of rib. There were 6 males and 10 females with an average age of 16.9 years (range, 10-24 years). There were 1 case of Lenke 1 curve, 9 cases of Lenke 2 curve, and 6 cases of Lenke 4 curve. The preoperative Cobb angle was (104.8 +/- 10.9) degrees and the preoperative thoracic kyphotic angle was (30.0 +/- 4.2) degrees. The preoperative height of "razor back" deformity was (5.9 +/- 1.2) cm. Before operation, the actual value of forced vital capacity (FVC) was (2.04 +/- 0.63) L and that of forced expiratory volume in 1 second (FEV1.0) was (1.72 +/- 0.62) L. The percentage of actual values to expected ones in FVC was 70% +/- 16%, and that in FEV1.0 was 67% +/- 15%. All patients had pulmonary function tests before operation and 3, 6, 12, 24 months after operation.

RESULTS

All wounds healed by first intention. The Cobb angle at 24-month follow-up was (53.4 +/- 18.6) degrees and the correction rate was 49.0% +/- 15.3%. The thoracic kyphotic angle at 24-month follow-up was (34.0 +/- 2.4) degrees and the correction rate was 13.3% +/- 2.2%. The height of "razor back" deformity at 24-month follow-up was (2.2 +/- 0.8) cm. Compared with preoperative level, all these data showed significant differences (P < 0.05). At 3 and 6 months, the actual values of FVC and FEV1.0 declined, but no significant difference was found (P > 0.05). At 12 and 24 months, the actual values of FVC and FEV1.0 were close to the preoperative level (P > 0.05). The percentages of actual values to expected ones in FVC and FEV1.0 indicate continued improvement in pulmonary function from the postoperative 3 to 24 months follow-up. Compared with preoperative level, the percentages of actual values in FVC declined 19% 3 months postoperatively (P < 0.05) and 12% 6 months postoperatively (P < 0.05). The percentages of actual values to expected ones in FEV1.0 declined 16% 3 months postoperatively (P < 0.05), and 10% 6 months postoperatively (P < 0.05). The percentages of actual values to expected ones in FVC and FEV1.0 were close to the preoperative level 12 and 24 months after operation (P > 0.05).

CONCLUSION

In severe scoliosis patients who are treated with anterior release, posterior segmental fixation and fusion, and convex thoracoplasty by resecting a short length of rib, pulmonary function decreases obviously 3-6 months after operation. And it returns to the operative baseline 12-24 months after operation.