title: Safety and efficacy of microsurgical treatment of previously coiled aneurysms: a systematic review and meta-analysis.
abstract: BACKGROUND
  We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.
  
  
  METHODS
  A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique. We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.
  
  
  RESULTS
  Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95 % CI = 2.6-7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI = 5.3-17.0 %) or parent vessel occlusion (13.1 %, 95 % CI = 4.6-21.6 %) (p = 0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI = 69.3-84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI = 89.0-95.2 %) (p < 0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p < 0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p < 0.01).
  
  
  CONCLUSIONS
  Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.
authors.affiliation: Department of Neurologic Surgery, Mayo Clinic, Rochester, 200 1st Street SW, Rochester, MN, 55905, USA. petr.ondra@mayo.edu.|Department of Neurosurgery, Medical University Innsbruck, Innsbruck, Austria. petr.ondra@mayo.edu.
authors.forename: Ondra
authors.identifier: http://orcid.org/0000-0002-7014-3571
authors.initials: O
authors.lastname: Petr
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Waleed
authors.initials: W
authors.lastname: Brinjikji
authors.affiliation: Department of Neurosurgery, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Claudius
authors.initials: C
authors.lastname: Thomé
authors.affiliation: Department of Neurologic Surgery, Mayo Clinic, Rochester, 200 1st Street SW, Rochester, MN, 55905, USA.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lanzino
mesh_terms: D002548:Cerebral Revascularization / Q000009:adverse effects*; D004621:Embolization, Therapeutic / Q000009:adverse effects*; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery*; D008866:Microsurgery / Q000009:adverse effects*
keywords: Meta-analysis; Microsurgery; Previously coiled aneurysm