Effect of Lung Volume Reduction Surgery on Bony Thorax Configuration in Severe COPD: Roentgenographic (Plain Film) Data

This contrasts with the significant reductions in thoracic dimensions seen 3 months after LVRS. Table 5 demonstrates rib cage dimensions measured using plain CXRs preoperatively and 3 months after LVRS. Compared with baseline, there were significant reductions in AP diameter at the levels of the manubrium and at T7, but not at T11. There were also significant reductions in transverse diameter at T7 and at T11; however, no change was seen at the level of the manubrium. Although the magnitude of these changes is small, and similar to the changes between the baseline and preoperative values in Table 4, the larger number of patients evaluated at 3 months compared with baseline accounts for the significance of these changes.
Roentgenographic (Thoracic CT) Data
Table 6 demonstrates rib cage dimensions measured using thoracic CT scans preoperatively and 3 months after LVRS. Compared with baseline, there was no significant postoperative change in maximal transverse diameter at all levels measured. The AP diameter, on the other hand, decreased significantly at the level of the mid-to-lower thorax. Although there was no change at T4, there were significant AP diameter reductions demonstrated at the T6, T8, and T10 levels. canadian health&care mall

Correlations
To evaluate the clinical significance of the above findings, the described changes in thoracic dimensions after LVRS were correlated with physiologic parameters. Figure 3 shows a potential mechanism for postoperative change in thoracic dimensions, by demonstrating correlations between the percent change in total lung capacity and the percent change in AP diameter of the lower rib cage, measured using the plain CXR (at T11) and the CT scan (at T8 and T10). Significant positive correlations were found between the postoperative reduction in total lung capacity and the decrease in AP diameter of the lower rib cage, as measured by plain CXR (r = 0.57, p = 0.03), and as measured by CT at T8 (r = 0.69, p = 0.01) and at T10 (r = 0.64, p = 0.03).
Positive correlations were also found between the postoperative reduction in residual volume (RV) and the decrease in AP diameter of the lower rib cage (Fig 4), but did not quite reach statistical significance, as measured by plain CXR (r = 0.47, p = 0.07), and by CT at T8 (r = 0.48, p = 0.1) and at T10 (r = 0.36, p = 0.2).

Table 5—Rib Cage Dimensions Before and 3 Mo After LVRS (Using Plain CXR; N = 25)

ExaminationTime AP Diameter, cm Transverse Diameter, cm
M T7 T11 M T7 T11
Baseline 21.3 ± 3.0 24.2 ± 2.0 24.6 ± 3.1 22.5 ± 2.1 26.8 ± 1.9 29.9 ± 2.2
Postoperative 20.9 ± 3.2 23.3 ± 2.2 24.0 ± 3.1 22.7 ± 1.9 26.4 ± 1.7 29.5 ± 2.2
p value 0.06 0.0002 0.2 0.5 0.01 0.03

Table 6—Rib Cage Dimensions Before and 3 Mo After LVRS (Using Thoracic CT Scans; N = 14)

Rib Location R C L T AP
T4, cm
Pre-LVRS 12.6 ± 2.2 10.4 ± 1.5 12.6 ± 2.1 21.2 ± 1.9 35.6 ± 6.4
Post-LVRS 11.8 ± 2.4 10.1 ± 1.4 12.3 ± 2.1 20.8 ± 2.0 34.2 ± 5.7
p value 0.2 0.4 0.6 0.3 0.4
T6, cm
Pre-LVRS 16.9 ± 1.9 14.7 ± 2.0 17.2 ± 1.9 23.9 ± 1.4 48.8 ± 6.0
Post-LVRS 16.1 ± 1.7 14.0 ± 1.5 16.6 ± 1.9 23.6 ± 1.4 46.7 ± 5.4
p value 0.003 0.08 0.07 0.2 0.02
T8, cm
Pre-LVRS 18.7 ± 2.2 16.5 ± 2.1 19.0 ± 2.2 24.7 ± 1.9 54.2 ± 7.0
Post-LVRS 18.1 ± 2.1 15.9 ± 1.9 18.3 ± 2.3 24.9 ± 1.4 52.3 ± 6.5
p value 0.01 0.01 0.005 0.8 0.004
T10, cm
Pre-LVRS 18.5 ± 2.3 16.7 ± 2.5 18.7 ± 2.5 26.5 ± 1.8 53.8 ± 7.5
Post-LVRS 17.7 ± 2.5 16.0 ± 2.6 17.5 ± 2.9 26.3 ± 1.9 51.3 ± 8.0
p value 0.002 0.02 0.001 0.3 0.001

 

Figure 3. Correlations between the percent change in TLC after LVRS and the percent change in AP diameter of the lower rib cage, measured on CXR (at T11) and on CT scan (at T8 and T10). This demonstrates that the post-LVRS reduction in lower AP diameter is directly related to reduction in lung volume.Figure 3. Correlations between the percent change in TLC after LVRS and the percent change in AP diameter of the lower rib cage, measured on CXR (at T11) and on CT scan (at T8 and T10). This demonstrates that the post-LVRS reduction in lower AP diameter is directly related to reduction in lung volume.

Figure 4. Correlations between the percent change in RV after LVRS and the percent change in AP diameter of the lower rib cage, measured on CXR (at T11) and on CT scan (at T8 and T10). This demonstrates that the post-LVRS reduction in lower AP diameter is directly related to reduction in lung volume.Figure 4. Correlations between the percent change in RV after LVRS and the percent change in AP diameter of the lower rib cage, measured on CXR (at T11) and on CT scan (at T8 and T10). This demonstrates that the post-LVRS reduction in lower AP diameter is directly related to reduction in lung volume.

Category: COPD

Tags: bony thorax, COPD, emphysema, lung volume reduction surgery, thoracic diameters