Risk Factors for Pneumothorax after Transthoracic Needle Aspiration Biopsy

 

Imaging techniques used: both CT guided and fluroscopically guided

 

Needle size used: from 18 to 22 gauge

 

Risk factors associated with pneumothorax:

(1) emphysema

(2) traversing aerated lung

(3) size of the lesion

 

Risk Factor	Finding	Percent with Pneumothorax
emphysema	absent	35%
	present	49%
traversing aerated lung	no (on pleural surface)	15%
	yes	45-50%
size of lesion	0 - 1.0 cm	65%
	1.01 - 2.0 cm	57%
	2.01 - 3.0 cm	36%
	3.01 - 4.0 cm	35%
	4.01 - 5.0 cm	21%
	> 5 cm	13%

 

where:

• I would think that a smaller lesion would be less likely to be on the pleural surface, so crossing aerated lung is more likely.

• It looks as if there are 3 clusters for risk based on lesion size: 55-65%, 35-36% and 12-21%.

• The data does not appear to have been analyzed using univariate or multivariate analysis. Since the lowest rate of pneumothorax (13% for size > 5 cm) is less than 35% for emphysema absent, it would be interesting to look at the full data set to see if patients with small tumors predominated.

 

Findings not associated with pneumothorax rate:

(1) lesion location (which lobe)

(2) needle size

(3) number of pleural passes (smaller lesions probably take more passes)

(4) level of operator training

 

It would seem that several risk groups can be recognized:

(1) low risk (no risk factors) - no emphysema, size > 4 cm, no aerated lung passed

(2) high risk (all 3 risk factors) - emphysema, size <= 2 cm, aerated lung passed