title: Raised intraocular pressure (IOP) and perioperative visual loss in laparoscopic colorectal surgery: a catastrophe waiting to happen? A systematic review of evidence from other surgical specialities.
abstract: BACKGROUND
  Case reports of healthy patients experiencing total perioperative visual loss (POVL) after elective laparoscopic surgery, including colorectal resection, are appearing increasingly frequently in the literature. We reviewed the literature exploring the relationship between patient positioning and intraocular pressure (IOP) across all surgical specialties. This was then applied to the potential risk of developing POVL in patients undergoing laparoscopic colorectal surgery.
  
  
  METHODS
  A systematic review of the relevant literature was performed to identify all studies exploring the relationship between intraocular pressure and patient positioning.
  
  
  RESULTS
  Eight relevant studies on both elective patients and healthy non-anaesthetised volunteers in the spinal, neurosurgical and urological fields were identified which explore the changes in IOP according to patient positioning. These all reported significant rises in IOP in both head-down positioning and prone positioning, and the strongest effects were seen in those patients placed in combined head-down and prone position (such as prone jackknife). Rises in IOP were time-dependent in all studies.
  
  
  CONCLUSIONS
  Patients undergoing laparoscopic colorectal surgery in a prolonged head-down position are likely to experience raised IOP and thus are at risk of POVL. Those having a laparoscopic abdominoperineal excision with prone positioning for the perineal component are probably those in the greatest danger. Surgeons need to be aware of this under-recognised but potentially catastrophic complication.
authors.affiliation: Department of Colorectal Surgery, Nottingham University Hospitals NHS Trust, Nottingham, UK. Thomas.pinkney@tiscali.co.uk
authors.forename: T D
authors.initials: TD
authors.lastname: Pinkney
authors.forename: A J
authors.initials: AJ
authors.lastname: King
authors.forename: C
authors.initials: C
authors.lastname: Walter
authors.forename: T R
authors.initials: TR
authors.lastname: Wilson
authors.forename: C
authors.initials: C
authors.lastname: Maxwell-Armstrong
authors.forename: A G
authors.initials: AG
authors.lastname: Acheson
mesh_terms: D001766:Blindness / Q000209:etiology* / Q000503:physiopathology; D003108:Colonic Diseases / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure; D010535:Laparoscopy / Q000009:adverse effects*; D056888:Patient Positioning / Q000009:adverse effects*; D011184:Postoperative Period; D012002:Rectal Diseases / Q000601:surgery