title: The estimation of postoperative bleeding after reduction of blowout fracture: the effectiveness of negative-pressure drainage system.
abstract: BACKGROUND
  Retrobulbar hemorrhage is a rare complication of midface injury, blepharoplasty, facial fracture surgery, periorbital surgery, and circumbulbar anesthesia. The incidence of postoperative retrobulbar hemorrhage is 0.3% to 4% after the reduction of facial bone fracture. The purpose of this study was to estimate the postoperative bleeding after the reduction of a blowout fracture and to demonstrate the effectiveness of a negative-pressure drainage system with a scalp vein set tube.
  
  
  METHODS
  From January 2006 to July 2013, we handled a total of 1491 cases of blowout fractures. Two of them (0.13%) were diagnosed as retrobulbar hematoma in 2011. After experiencing 2 cases of retrobulbar hematoma, we have been routinely using a scalp vein set tube as a negative-pressure drainage system to check the postoperative blood volume.
  
  
  RESULTS
  From January 2012 to July 2013, a total of 131 patients underwent blowout fracture repair and experienced application of a negative-pressure drainage system. Their mean total drained amount was 12.6 mL; maximum amount was 47.5 mL in the 2 days after the surgery. The maximum drained amount was 41.7 mL on the day of the surgery. All the patients had no cardinal signs or symptoms of retrobulbar hematoma and no complications.
  
  
  CONCLUSIONS
  Retrobulbar hematoma is a rare but critical surgical complication that leads to permanent visual loss. Considering the limited orbital cavity and postoperative edema, the volume of postoperative bleeding is thought to be enough to compress the optic nerve if the blood is not drained. Thus, we recommended a simple negative-pressure drainage system to prevent retrobulbar hematoma.
authors.affiliation: Department of Plastic and Reconstructive Surgery, School of Medicine, Chosun University, Gwangju, Korea.
authors.forename: Cheol Woo
authors.initials: CW
authors.lastname: Park
authors.forename: Jeong Yeol
authors.initials: JY
authors.lastname: Yang
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Son
authors.forename: Ji Seon
authors.initials: JS
authors.lastname: Cheon
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000601:surgery*; D009917:Orbital Fractures / Q000601:surgery*; D019106:Postoperative Hemorrhage / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D056910:Republic of Korea / Q000453:epidemiology; D019315:Retrobulbar Hemorrhage / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D055815:Young Adult