title: Laser surgery in twin-twin transfusion syndrome with proximate cord insertions.
abstract: OBJECTIVE
  To estimate the prevalence of proximate cord insertions in twin-twin transfusion syndrome (TTTS) and evaluate the outcome after fetoscopic laser coagulation surgery.
  
  
  METHODS
  We included all TTTS cases treated with laser at our center between 2002 and 2013. Placentas were examined after birth and injected with colored dye. TTTS cases without complete placental injection study were excluded. We recorded the presence of proximate cord insertions (distance < 5 cm) after birth and the presence and types of residual anastomoses. We compared the clinical outcome and placental findings in cases with and without proximate cord insertions.
  
  
  RESULTS
  The prevalence of proximate cord insertions in TTTS placentas was 2% (4/252). Perinatal mortality in the TTTS group with and without proximate cord insertions was 13% (1/8) and 12% (61/496), respectively (P = 1.0). Residual anastomoses were detected in all placentas with proximate cord insertions (100%, 4/4) compared to 27% (66/248)(P < .01) in TTTS placentas without proximate cord insertions.
  
  
  CONCLUSIONS
  Fetoscopic laser coagulation in TTTS cases with proximate cord insertions is challenging due to technical difficulties in visualizing the vascular equator and results in an increased risk of incomplete laser treatment.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, J6-S, Albinusdreef 2, 2333 ZA Leiden, The Netherlands. Electronic address: d.zhao@lumc.nl.
authors.forename: D P
authors.initials: DP
authors.lastname: Zhao
authors.forename: S H P
authors.initials: SH
authors.lastname: Peeters
authors.forename: J M
authors.initials: JM
authors.lastname: Middeldorp
authors.forename: F J
authors.initials: FJ
authors.lastname: Klumper
authors.forename: D
authors.initials: D
authors.lastname: Oepkes
authors.forename: E
authors.initials: E
authors.lastname: Lopriore
mesh_terms: D000046:Academic Medical Centers; D000714:Anastomosis, Surgical / Q000009:adverse effects; D057868:Anastomotic Leak / Q000453:epidemiology / Q000517:prevention & control*; D004396:Coloring Agents / Q000008:administration & dosage / Q000737:chemistry; D005260:Female; D005330:Fetofetal Transfusion / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005332:Fetoscopy; D006801:Humans; D007275:Injections, Intravenous; D017075:Laser Coagulation / Q000009:adverse effects*; D009426:Netherlands / Q000453:epidemiology; D054238:Perinatal Mortality; D010781:Photography; D010920:Placenta / Q000473:pathology / Q000601:surgery*; D021041:Placental Circulation; D011247:Pregnancy; D047928:Premature Birth; D015995:Prevalence; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014470:Umbilical Cord / Q000473:pathology / Q000601:surgery*
chemical_list: D004396:Coloring Agents
keywords: Fetoscopic laser coagulation surgery; Proximate umbilical cord insertions; Twin–twin transfusion syndrome