Pneumothorax after CT-guided transthoracic lung biopsy: A comparison between immediate and delayed occurrence

Background In CT-guided transthoracic lung biopsy (CTLB), pneumothorax can occur as a late complication (delayed pneumothorax). The incidence, risk factors, and clinical significance of delayed pneumothorax are not well known. Objectives To compare the risk factors for immediate and delayed pneumothorax after CTLB and to know their clinical significance. Methods Images and medical records of 536 consecutive patients who underwent CTLB were reviewed. All biopsies were performed as inpatient procedures. Follow-up chest radiographs were obtained at least twice at 4 h after procedure and before discharge. Risk factors for immediate and delayed pneumothorax were assessed based on patient-, lesion-, and procedure-related variables. Rates of chest tube insertion were also compared. Results Pneumothorax developed in 161 patients (30.0%) including 135 (25.2%) immediate and 26 (4.9%) delayed cases. Lesion size was an independent risk factor for both immediate and delayed pneumothorax (OR = 0.813; CI = 0.717-0.922 and OR = 0.610; CI = 0.441-0.844, respectively). While emphysema, lower lobe location, and long intrapulmonary biopsy track were risk factors (OR = 1.981; CI = 1.172-3.344, OR = 3.505; CI = 2.718-5.650, and OR = 1.330; CI = 1.132-1.563, respectively) for immediate pneumothorax, upper lobe location and increased number of pleural punctures were independent risk factors (OR = 5.756; CI = 1.634-20.274 and OR = 3.738; CI = 1.860-7.511, respectively) for delayed pneumothorax. The rate of chest tube insertion was significantly (p< 0.001) higher in delayed pneumothorax. Conclusion Pneumothorax tends to occur immediately after CTLB in patients with emphysema, lower lobe lesion, and long intrapulmonary biopsy track. Further attention and warnings are needed for those with multiple punctures of small lesions involving upper lobes due to the possibility of delayed development of pneumothorax and higher requirement for chest tube drainage.