Prospective pulmonary function comparison following posterior segmental spinal instrumentation and fusion of adolescent idiopathic scoliosis: is there a relationship between major thoracic curve correction and pulmonary function test improvement?

STUDY DESIGN

Prospective clinical study.

OBJECTIVE

To investigate if a correlation exists between various parameters including major thoracic curve correction and postoperative pulmonary function test (PFT) improvement at 2 years postoperative following posterior segmental spinal fusion (PSSF) and instrumentation with iliac crest bone graft (ICBG).

SUMMARY OF BACKGROUND DATA

There are no studies available on the correlation between major thoracic curve correction and postoperative PFT improvement following PSSF and instrumentation with ICBG with a homogenous diagnosis, similar operation method, and similar age population.

METHODS

One hundred thirty-nine patients with adolescent idiopathic scoliosis (Lenke type 1-4), undergoing PSSF and instrumentation with ICBG at a single institution, were before surgery and 2 years after surgery prospectively evaluated in regard to PFTs, assessing forced vital capacity, and forced expiratory volume in 1 second. PFTs change at 2 years postoperative was compared by the various parameters including major thoracic Cobb curve correction and the types of instrumentation. We defined a significant clinical improvement as a 10% or more increase of percent predictive FEV1 value at 2 years postoperative.

RESULTS

PSSF and instrumentation with ICBG demonstrated statistically significant improvement of absolute and percent-predicted PFTs at 2 years postoperative. There was a significant clinical improvement in 31 patients (22%) at 2 years postoperative. Significant clinical improvement was related to thoracic pedicle screw instrumentation (vs. thoracic hook instrumentation, P = 0.030). Absolute amount of major thoracic Cobb correction, magnitude of the residual curve, correction percentage of the major thoracic Cobb, the number of fused vertebrae, Risser sign, and age at surgery did not demonstrate any significant positive or negative correlation (-0.3 <Pearson correlation coefficient <0.3).

CONCLUSIONS

Patients having a PSSF and instrumentation with ICBG statistically significant improvement of absolute and percent-predicted PFTs at 2 years postoperative. There was a significant clinical improvement in 31 patients (22%) at 2 years postoperative. A significant clinical improvement was related with thoracic pedicle screw instrumentation.