title: The twist technique: a method to minimize wire prolapse during Bird's Nest filter placement.
abstract: OBJECTIVE
  To determine whether a twist technique can help reduce the occurrence of fine-wire prolapse proximal to the hooks of the Bird's Nest filter in the inferior vena cava.
  
  
  METHODS
  Abdominal radiographs were retrospectively analyzed after placement of filters with no twist (n = 100), with two 360 degree twists (n = 55), or with three 360 degree twists (n = 61).
  
  
  RESULTS
  Prolapse of 5 mm or more was encountered in 32% of cases (32 of 100 cases) in which no twists were imparted. The average length of prolapse was 2.8 cm (range, 0.5-5.1 cm). The average length of the filter nest was 9.4 cm (range 5.1-13.6 cm). Use of two 360 degree twists reduced the rate of prolapse to 9.1% (five of 55 cases) (P < .005 vs no twist); the average length of prolapse was 2.8 cm (range, 0.6-6.4 cm). The average filter-nest length was reduced 7.5 cm (range, 4.0-13.3 cm). With three 360 degree twists, prolapse occurred in 4.9% of cases (three of 61 cases) (P < .005 vs no twist). The average length of prolapse was 2.6 cm (range, 0.7-4.8 cm). The average filter-nest length was 7.8 cm (range, 3.5-12.8 cm). The difference in prolapse frequency when two twists were used as opposed to three is not statistically significant.
  
  
  CONCLUSIONS
  Application of two or three 360 degree twists to the catheter-sheath unit during insertion of the Bird's Nest filter produces a statistically significant reduction in the occurrence of wire prolapse.
authors.affiliation: Section of Cardiovascular and Interventional Radiology, Methodist Hospital, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: J O
authors.initials: JO
authors.lastname: Roehm
authors.forename: J W
authors.initials: JW
authors.lastname: Thomas
mesh_terms: D002405:Catheterization, Central Venous / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D004868:Equipment Failure; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000517:prevention & control; D006801:Humans; D011859:Radiography; D012189:Retrospective Studies; D012399:Rotation; D013499:Surface Properties; D013927:Thrombosis / Q000517:prevention & control; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging