title: Occult diaphragmatic injuries caused by stab wounds.
abstract: BACKGROUND
  Missed diaphragmatic perforation caused by penetrating trauma can lead to subsequent strangulation of a hollow viscus, which has prompted the use of invasive diagnostic procedures to exclude occult diaphragmatic injuries in asymptomatic, high-risk patients. The objective of this study was to determine the incidence of occult diaphragmatic injuries caused by stab wounds of the lower chest and upper abdomen, and to examine the natural history and consequences of missed diaphragmatic injuries.
  
  
  METHODS
  On the basis of patient data from two previous randomized studies from our institution, a retrospective analysis was performed on 97 patients treated for anterior stab wounds located between the nipple line, the umbilical level, and the posterior axillary lines not having indications for immediate surgical exploration. The patients were divided into two groups on the basis of their initial randomized management (open or laparoscopic exploration vs. expectant observation).
  
  
  RESULTS
  In the exploration group (n = 47), four diaphragmatic injuries (9%) were detected (three left-sided and one right-sided). Excluding patients with associated injuries requiring surgical repair, the incidence of occult diaphragmatic injuries was 3 of 43 (7%). In the observation group (n = 50), there were two patients (4%) with delayed presentation of missed left-sided diaphragmatic injury 2 and 23 months later, respectively. Both injuries resulted from stab wounds of the left flank and presented with herniation of the stomach or small bowel and colon. The overall incidence of occult diaphragmatic injuries in left-sided thoracoabdominal stab wounds was 4 of 24 (17%), and was much lower after stab wounds of left epigastrium (0%), right lower chest (0%), and right epigastrium (4%).
  
  
  CONCLUSIONS
  In asymptomatic patients with anterior or flank stab wounds of the lower chest or upper abdominal area, the risk of an occult diaphragmatic injury is approximately 7% which, if undetected, is associated with a high risk of subsequent hollow viscus herniation. Exclusion of an occult diaphragmatic injury with invasive diagnostic methods, such as laparoscopy or thoracoscopy, should be considered at least in left-sided stab wounds of the lower chest.
authors.affiliation: Department of Surgery, University of Helsinki, Helsinki, Finland. ari.leppaniemi@hus.fi
authors.forename: Ari
authors.initials: A
authors.lastname: Leppäniemi
authors.forename: Reijo
authors.initials: R
authors.lastname: Haapiainen
mesh_terms: D000328:Adult; D003964:Diaphragm / Q000293:injuries*; D005260:Female; D017721:Hospital Costs; D006801:Humans; D015994:Incidence; D015601:Injury Severity Score; D010535:Laparoscopy / Q000191:economics; D008297:Male; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014951:Wounds, Stab / Q000175:diagnosis* / Q000191:economics / Q000453:epidemiology