title: Timing of retreatment for patients with previously coiled or clipped intracranial aneurysms: Analysis of 156 patients with multiple treatments.
abstract: BACKGROUND
  Some patients require a second surgical intervention for recurrence of treated aneurysms, untreated aneurysms in patients with multiple lesions, or de novo aneurysm. This retrospective review of the data was undertaken to evaluate when retreatment is necessary after initial aneurysm treatment.
  
  
  METHODS
  Cerebral aneurysms in 1755 patients were treated via clipping or coiling between January 1995 and September 2012. Postoperative follow-up was performed at 6 months after treatment and was repeated every 12 months (or longer) after treatment using three-dimensional computed tomography angiography or magnetic resonance angiography.
  
  
  RESULTS
  A cumulative total of 156 patients (8.9%) (117 women, 39 men; mean age: 55.0 years; range: 25-79 years) needed retreatment for rupture or regrowth of aneurysm (n = 31; ruptured (R)/remaining unruptured (U), 26/5), formation of de novo aneurysm (n = 45; R/U, 23/22), known untreated aneurysm in patients with multiple lesions (n = 78; R/U, 5/73), and hemorrhage from undetected aneurysm (n = 2). The regrowth risk is higher after endovascular treatment than after craniotomy and clipping. Median time to retreatment was 187 months (range: 11-280 months) for regrowth, 165 months (range: 22-330 months) for de novo, and 24 months (range: 2.8-417 months) for known untreated aneurysm. Regrowth or known with subarachnoid hemorrhage were frequently treated within 2 years from initial treatment.
  
  
  CONCLUSIONS
  Aneurysms with residua or untreated aneurysms in patients with multiple lesions carry a risk of bleeding during a relatively short period, whereas there is a small but significant risk of de novo formation and subsequent hemorrhage at over 10 years after previous treatment.
authors: Department of Surgical Neurology, Research Institute for Brain and Blood Vessels Akita, Akita, Japan.
authors: Takeshi
authors: T
authors: Okada
authors: Department of Surgical Neurology, Research Institute for Brain and Blood Vessels Akita, Akita, Japan.
authors: Tatsuya
authors: T
authors: Ishikawa
authors: Department of Surgical Neurology, Research Institute for Brain and Blood Vessels Akita, Akita, Japan.
authors: Junta
authors: J
authors: Moroi
authors: Department of Surgical Neurology, Research Institute for Brain and Blood Vessels Akita, Akita, Japan.
authors: Akifumi
authors: A
authors: Suzuki
keywords: De novo aneurysm; follow-up; intracranial aneurysm; regrown aneurysm; retreatment