title: Recurrent twin-twin transfusion syndrome after selective fetoscopic laser photocoagulation: a systematic review of the literature.
abstract: OBJECTIVE
  Selective fetoscopic laser photocoagulation (SFLP) is now the treatment of choice for twin-twin transfusion syndrome (TTTS). The incidence of recurrent TTTS following SFLP has been inconsistently reported across different studies. We performed a systematic review of TTTS recurrence following SFLP.
  
  
  METHODS
  PubMed and MEDLINE online databases were searched for articles published between 2000 and August 2011, using combinations of the terms 'twin-twin transfusion', 'TTTS', 'laser', 'recur' and 'outcome'. Citations identified in the primary search were screened for eligibility. Studies reporting outcomes from selective SFLP for TTTS in twin pregnancies, which addressed specifically the issue of TTTS recurrence, were included. The primary outcome was rate of TTTS recurrence. Secondary outcomes were therapeutic preference and fetal outcomes in cases of recurrent TTTS.
  
  
  RESULTS
  The primary search identified 22 eligible studies that are included in this review (n = 2447 twin pregnancies). Two studies included a minority of non-selective procedures. The published incidence of recurrent TTTS ranged from 0 to 16%. Clinical management was reported in 65.7% (71/108) cases, with repeat SFLP the most commonly performed secondary intervention. Only three studies provided comprehensive outcome data for cases of recurrent TTTS. The overall rate of neurologically-intact survival was 44% (23/52). The data were inadequate to determine the effects of secondary therapeutic approach, placental location or gestational age on perinatal outcome in cases of recurrent TTTS.
  
  
  CONCLUSIONS
  The published rate of TTTS recurrence following SFLP in monochorionic twin pregnancies ranges from 0 to 16%. Although limited follow-up data suggest that recurrence is associated with significant perinatal mortality and morbidity, further study is needed. Currently, there are insufficient data available to guide recommendations for clinical management of TTTS recurrence. Future studies on SFLP for TTTS must include details on recurrence rates and provide outcome data specific to the recurrent subset.
authors.affiliation: Department of Fetal Medicine, National Maternity Hospital, Dublin, Ireland.
authors.forename: C A
authors.initials: CA
authors.lastname: Walsh
authors.forename: F M
authors.initials: FM
authors.lastname: McAuliffe
mesh_terms: D000328:Adult; D005260:Female; D005330:Fetofetal Transfusion / Q000601:surgery*; D005332:Fetoscopy; D006801:Humans; D017075:Laser Coagulation / Q000379:methods*; D011247:Pregnancy; D059285:Pregnancy, Twin; D012008:Recurrence