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Communications to the Editor |

Blebs and/or Bullae Are of No Importance and Have No Predictive Value for Recurrences in Patients With Primary Spontaneous PneumothoraxBlebs and/or Bullae Are of No Importance and Have No Predictive Value for Recurrences in Patients With Primary Spontaneous Pneumothorax FREE TO VIEW

F. M. N. H. Schramel, MD, PhD, FCCP; P. Zanen, MD, PhD
Author and Funding Information

Affiliations: St. Antonius Hospital Nieuwegein, The Netherlands,  Prince of Wales Hospital Hong Kong, China

Correspondence to: F. M. N. H. Schramel, MD, PhD, FCCP, Department of Pulmonary Diseases, St. Antonius Hospital, PO Box 2500, 3430 CM Nieuwegein, The Netherlands; e-mail: antolong@knmg.nl



Chest. 2001;119(6):1976-1977. doi:10.1378/chest.119.6.1976-a
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To the Editor:

Sihoe et al (August 2000)1 described a study in which they tested the hypothesis that thoracic CT scanning could help to predict the probability of the occurrence of primary spontaneous pneumothorax (SP) by detecting lung bullae. Several studies have been performed concerning the possible relationship of blebs and/or bullae to the development of recurrent primary SP that do not confirm the conclusion of Sihoe et al.

Mitlehner et al2analyzed 35 patients with primary SP who underwent thoracic CT scans. The presence of blebs and/or bullae had no predictive value for recurrences during follow-up. Smit et al3studied 101 patients with first-time and recurrent SPs who underwent thoracic CT scans. In 12 patients, bilateral pneumothoraces occurred. The percentages of patients who had bullae among those with first-time SPs and recurrent SPs were not significantly different, nor was the percentage of bullae that occurred on the pneumothorax side significantly different compared to those occurring on the contralateral side. Janssen et al4 could not demonstrate differences in the presence of blebs and/or bullae during video-assisted thoracoscopy in patients with first-time or recurrent SPs.

In patients with COPD, bullae frequently can be detected. A study by Videm et al5in 303 patients with primary and secondary SPs showed no significant relationship between the recurrence rate of SPs and COPD. Independent risk factors for recurrence in 122 patients with primary SPs were reported as follows: pulmonary fibrosis detected on chest radiographs; physical characteristics; smoking behavior; and age.6

From these findings, one can conclude that the presence of blebs and/or bullae in patients with primary SPs has no predictive value for the future development of recurrences. Therefore, investigations to diagnose blebs and/or bullae should not influence the choice of treatment to prevent future recurrences.7 Obviously, Sihoe et al1 did not review the literature as stated above and therefore performed a study with a noninteresting study objective.

Sihoe et al1 showed a significant difference in the occurrence of contralateral SP between patients with or without contralateral blebs and/or bullae (p = 0.04). Table 1 shows the data in a 2 × 2 manner. The Pearsonχ 2 test was used. However, this test is only applicable when cells of the 2 × 2 table contain a minimum frequency, which was not the case in the study by Sihoe et al.,1 A zero value in one of the four cells invalidates the test. The results of the test are therefore questionable and may be biased. Other approaches to test for significance in a 2 × 2 table (eg, Fisher’s Exact Test) did not show significance.

The conclusions of Sihoe et al1 are based on an incorrect statistical analysis. Several other studies from the past have shown that blebs and/or bullae have no prognostic value in predicting future recurrences of SP and should not be used for selecting the right therapy. Therefore, we cannot agree with Sihoe et al1 that the detection of lung bullae by CT scanning in the contralateral lung in patients with primary SPs could have predictive value for the recurrence of SP and can be used to select patients for surgery.

Table Graphic Jump Location
Table 1. 2 × 2 Table Relating Recurrent SP to the Presence of Blebs and Bullae
Sihoe, ADL, Yim, APC, Lee, TW, et al (2000) Can CT scanning be used to select patients with unilateral primary spontaneous pneumothorax for bilateral surgery?Chest118,380-383. [CrossRef]
 
Mitlehner, W, Friedrich, M, Dissmann, W Value of computer tomography in the detection of bullae and blebs in patients with primary spontaneous pneumothorax.Respiration1992;59,221-227. [CrossRef]
 
Smit, HJ, Wienk, MA, Schreurs, AJ, et al Do bullae indicate a predisposition to recurrent pneumothorax?Br J Radiol2000;73,356-359. [CrossRef]
 
Janssen, JP, Schramel, FMNH, Sutedja, TG, et al Videothoracoscopic appearance of first and recurrent pneumothorax.Chest1995;108,330-334. [CrossRef]
 
Videm, V, Pilgram-Larsen, J, Ellingsen, O, et al Spontaneous pneumothorax in chronic obstructive pulmonary disease: complications, treatment and recurrences.Eur J Respir Dis1987;71,365-371
 
Lippert, HL, Lund, O, Blegvad, S, et al Independent risk factors for cumulative recurrence rate after first spontaneous pneumothorax.Eur Respir J1991;4,324-331
 
Schramel, FMNH, Postmus, PE, Vanderschueren, RGJRA Current aspects of spontaneous pneumothorax.Eur Respir J1997;10,1372-1379. [CrossRef]
 

Blebs and/or Bullae Are of No Importance and Have No Predictive Value for Recurrences in Patients With Primary Spontaneous Pneumothorax

To the Editor:

We thank Drs. Schramel and Zanen for their interest in our work. Many of the points they raised in their letter were almost identical to those of Dr. Marc Noppen1. For the sake of space, we will not repeat ourselves and readers are asked to refer to our reply to Dr. Noppen’s letter, in which several issues were fully addressed.

We are well aware of the studies cited by Drs. Schramel and Zanen in their letter, but we disagree that they amount to definitive proof that bullae are of no predictive value for the recurrence of primary spontaneous pneumothorax (PSP). In the article by Mitlehner and colleagues,2blebs or bullae could be found in 31 of 35 patients with PSP. On follow-up of 32 of the 35 patients for an average of 32 months, 8 patients (25%) had recurrences of PSP. Although there was no control group in this study, the recurrence rate was far higher than would have been expected from the general population. In an earlier article by Lesur and associates3 studying CT scan findings in patients with PSP vs healthy individuals matched for age, sex, and smoking habits, significantly more “emphysematous lesions” were found in the PSP group.

In the articles by Smit et al4and Janssen et al5 (Dr. Schramel was a coauthor of both articles), which looked at CT scan and video-assisted thoracoscopic findings in patients with PSP, no differences in the bulla morphology could be found in patients with first-time vs recurrent PSP. The authors argued, therefore, that bullae have no bearing on PSP recurrence. However, this conclusion seemed to be based more on their opinion than on evidence. There were no control groups or follow-up data in either study. This would be analogous to a cross-sectional study with a small cohort of smokers in which smoking habits were analyzed. If no significant correlation could be found between the amount of smoking and the presence of lung cancer, it could be concluded that smoking was not a cause of cancer!

Until more knowledge on the pathogenesis of PSP becomes available, the exact relationship between bullae and PSP is likely to remain controversial. Scientific knowledge is built up from small additive increments, and it is important that we should keep an open mind on this subject and allow new evidence to speak for itself.

References
Noppen, M CT scanning and bilateral surgery for unilateral primary pneumothorax?Chest2001;119,1293-1294
 
Mitlehner, W, Friedrich, M, Dissmann, W Value of computer tomography in the detection of bullae and blebs in patients with primary spontaneous pneumothorax.Respiration1992;59,221-227. [CrossRef]
 
Lesur, O, Delorme, N, Fromaget, JM, et al Computed tomography in the etiologic assessment of idiopathic spontaneous pneumothorax.Chest1990;98,341-347. [CrossRef]
 
Smit, HJ, Wienk, MA, Schreurs, AJ, et al Do bullae indicate a predisposition to recurrent pneumothorax?Br J Radiol2000;73,356-359. [CrossRef]
 
Janssen, JP, Schramel, FMNH, Sutedja, TG, et al Videothoracoscopic appearance of first and recurrent pneumothorax.Chest1995;108,330-334. [CrossRef]
 

Figures

Tables

Table Graphic Jump Location
Table 1. 2 × 2 Table Relating Recurrent SP to the Presence of Blebs and Bullae

References

Sihoe, ADL, Yim, APC, Lee, TW, et al (2000) Can CT scanning be used to select patients with unilateral primary spontaneous pneumothorax for bilateral surgery?Chest118,380-383. [CrossRef]
 
Mitlehner, W, Friedrich, M, Dissmann, W Value of computer tomography in the detection of bullae and blebs in patients with primary spontaneous pneumothorax.Respiration1992;59,221-227. [CrossRef]
 
Smit, HJ, Wienk, MA, Schreurs, AJ, et al Do bullae indicate a predisposition to recurrent pneumothorax?Br J Radiol2000;73,356-359. [CrossRef]
 
Janssen, JP, Schramel, FMNH, Sutedja, TG, et al Videothoracoscopic appearance of first and recurrent pneumothorax.Chest1995;108,330-334. [CrossRef]
 
Videm, V, Pilgram-Larsen, J, Ellingsen, O, et al Spontaneous pneumothorax in chronic obstructive pulmonary disease: complications, treatment and recurrences.Eur J Respir Dis1987;71,365-371
 
Lippert, HL, Lund, O, Blegvad, S, et al Independent risk factors for cumulative recurrence rate after first spontaneous pneumothorax.Eur Respir J1991;4,324-331
 
Schramel, FMNH, Postmus, PE, Vanderschueren, RGJRA Current aspects of spontaneous pneumothorax.Eur Respir J1997;10,1372-1379. [CrossRef]
 
Noppen, M CT scanning and bilateral surgery for unilateral primary pneumothorax?Chest2001;119,1293-1294
 
Mitlehner, W, Friedrich, M, Dissmann, W Value of computer tomography in the detection of bullae and blebs in patients with primary spontaneous pneumothorax.Respiration1992;59,221-227. [CrossRef]
 
Lesur, O, Delorme, N, Fromaget, JM, et al Computed tomography in the etiologic assessment of idiopathic spontaneous pneumothorax.Chest1990;98,341-347. [CrossRef]
 
Smit, HJ, Wienk, MA, Schreurs, AJ, et al Do bullae indicate a predisposition to recurrent pneumothorax?Br J Radiol2000;73,356-359. [CrossRef]
 
Janssen, JP, Schramel, FMNH, Sutedja, TG, et al Videothoracoscopic appearance of first and recurrent pneumothorax.Chest1995;108,330-334. [CrossRef]
 
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