title: Delayed and recurrent pneumothorax after radiofrequency ablation of lung tumors.
abstract: BACKGROUND
  In daily clinical work, we often face delayed or recurrent pneumothorax after radiofrequency (RF) ablation for lung tumors, but a large study on this theme has not been done. Thus, we examined the rate of delayed or recurrent pneumothorax after RF ablation for lung tumors and the risk factors associated with its occurrence.
  
  
  METHODS
  This retrospective study was based on 194 consecutive sessions of percutaneous RF ablation of 220 lung tumors in 68 patients performed under CT fluoroscopic guidance at a single institution. Numerous variables were analyzed to the assess risk factors for delayed or recurrent pneumothorax.
  
  
  RESULTS
  Pneumothorax after RF ablation occurred in 82 of 194 ablation sessions (42.3%). Thirty-three of 82 sessions had either delayed pneumothorax (n = 20) or recurrent pneumothorax (n = 13). The other 49 sessions had nonprogressive pneumothorax. Only contact of the ground-glass opacity (GGO) that emerged around the ablated lesion with the pleura significantly correlated with the frequency of delayed or recurrent pneumothorax in comparisons between no pneumothorax vs delayed/recurrent pneumothorax and between nonprogressive pneumothorax vs delayed/recurrent pneumothorax. The mean (+/- SD) duration before confirmation of the presence or recurrence of pneumothorax was 24.0 +/- 66.4 h. Among the 33 sessions with delayed or recurrent pneumothorax, 4 subjects needed additional treatment.
  
  
  CONCLUSIONS
  Our results indicated that delayed or recurrent pneumothorax is relatively frequently encountered after RF ablation of lung tumors. Particular care must be taken with regard to the occurrence of delayed or recurrent pneumothorax when contact of a GGO with the pleura is seen after RF ablation.
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. Electronic address: rika442@koto.kpu-m.ac.jp.
authors.forename: Rika
authors.initials: R
authors.lastname: Yoshimatsu
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Yamagami
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Koshi
authors.initials: K
authors.lastname: Terayama
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miura
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Nishimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011030:Pneumothorax / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D011183:Postoperative Complications; D012008:Recurrence; D013997:Time Factors; D014057:Tomography, X-Ray Computed