title: Percutaneous radiofrequency ablation of hepatic tumors against the diaphragm: frequency of diaphragmatic injury.
abstract: OBJECTIVE
  To retrospectively determine the frequency of diaphragmatic injury when percutaneous hepatic radiofrequency (RF) ablation is performed adjacent to the diaphragm.
  
  
  METHODS
  Institutional Review Board approval was obtained for our HIPAA-compliant study. Informed consent for the ablation procedure and for use of related data for future research was obtained from each patient. A retrospective review was conducted of 215 patients undergoing percutaneous RF ablation of hepatic tumors. Twenty-nine patients (21 men and eight women; age, 41-89 years) were identified with tumors abutting the diaphragm. Episodes of right shoulder pain were recorded. A panel of radiologists blinded to the patients' clinical histories reviewed their imaging for evidence of diaphragmatic injury and ablation success. A generalized estimating equation model and the Fisher exact test were used for statistical analysis.
  
  
  RESULTS
  The 29 patients had a total of 33 tumors abutting the diaphragm. Tumor size was 1.3-5.5 cm (mean, 3.2 cm +/- 1.1). After ablation, five (17%) patients reported right shoulder pain. In four, pain was mild or moderate, with symptoms lasting 2-14 days (median, 5.5 days). Three of these showed diaphragmatic thickening on postablation computed tomographic (CT) scans. One patient had severe pain lasting 2 weeks, followed by milder pain for 2 months. This patient's postablation CT images showed focal nodular diaphragmatic thickening. This patient was treated with a multitined device; the other four, with straight-needle devices. Local tumor progression was seen in 14 tumors (42.4%). Tumors 3 cm or smaller had a much lower local progression rate than tumors larger than 3 cm (12.5% vs 70.6%).
  
  
  CONCLUSIONS
  Of 29 patients who had ablation of hepatic tumors adjacent to the diaphragm, five (17%) had diaphragmatic injury, which was clinically apparent with right shoulder pain.
authors.affiliation: Department of Radiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, Mail Code 7800, San Antonio, TX 78229, USA. headh@uthscsa.edu
authors.forename: Hayden W
authors.initials: HW
authors.lastname: Head
authors.forename: Gerald D
authors.initials: GD
authors.lastname: Dodd
authors.forename: Neal C
authors.initials: NC
authors.lastname: Dalrymple
authors.forename: Srinivas R
authors.initials: SR
authors.lastname: Prasad
authors.forename: Fadi M
authors.initials: FM
authors.lastname: El-Merhi
authors.forename: Michael W
authors.initials: MW
authors.lastname: Freckleton
authors.forename: Linda G
authors.initials: LG
authors.lastname: Hubbard
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000706:statistics & numerical data*; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000293:injuries*; D005260:Female; D006801:Humans; D015994:Incidence; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D020069:Shoulder Pain / Q000175:diagnosis / Q000453:epidemiology*; D013781:Texas / Q000453:epidemiology; D016896:Treatment Outcome