Does needle gauge affect complication rates of computed tomography-guided lung biopsy?

Background: It has been thought a larger bore biopsy needle may yield a better sample for molecular testing, but this could potentially expose the patient to higher pneumothorax rates. This study aims to determine if a larger bore biopsy system results in more complications.

Methods: A total of 193 patients who underwent computed tomography (CT)-guided lung biopsy in a single tertiary center from 2013-2021 were evaluated retrospectively. Patients were divided into two groups, patients who underwent lung biopsy using the 17/18-gauge (18G) biopsy system and the 19/20-gauge (20G) biopsy system. Data recorded included biopsy needle gauge, nodule location and size, plug use, positioning, the length of the intraparenchymal tract, number of biopsy passes, pneumothorax, chest tube insertion, and admission.

Results: The mean age was 64.1±12.4 years. The median diameter of the lung nodules was 1.95 cm, and the median depth of the intraparenchymal needle tract was 2.7 cm. Pneumothorax was identified during the procedure by CT fluoroscopy or on post-procedural chest X-ray (CXR). The overall rate of pneumothorax among all patients was 35.2%, and 10.9% of the study population (i.e., 30.1% of patients with pneumothorax) required chest tube insertion. The rate of pneumothorax or chest tube insertion was not significantly different between patients who underwent lung biopsy using 17/18G or 19/20G biopsy system. Patients who developed pneumothorax were older, with smaller-sized pulmonary nodules and longer length of the intraparenchymal tract. The pathologic sensitivity of the 18G gun was higher than that of the 20G gun (93% sensitivity, 100% specificity vs. 79.5% sensitivity, 100% specificity). In the multivariate logistic regression fitted model, the length of the intraparenchymal tract was the only factor predictive of post-procedural pneumothorax and chest tube insertion. An intraparenchymal needle tract length of greater than 2 cm was identified to have the best threshold to predict pneumothorax [sensitivity: 73.5%; false positive rate: 57.6%; area under the curve: 66.27%].

Conclusions: Findings suggest similar rates of pneumothorax and chest tube insertion using small 19/20G vs. 17/18G biopsy systems. The 18G system was more sensitive compared to the 20G system in determining pathologic results. Increasing length of lung parenchyma needle tract and smaller lung nodules appear to be risk factors for pneumothorax. Physicians should plan on intraparenchymal tracts that are less than 2 cm to decrease the chance of pneumothorax.