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Physical function among children born extremely premature

-  with or without paresis of n.recurrens following surgical closure of patent ductus arteriosus


In Norway, about 300 children are born extremely premature (< 28 weeks / < 1000g) every year.

Due to development in intensive care, survival among extremely premature born (EPB) children increased from about zero survival to approximately 80% survival from the 1960`s to the 1980`s. However, EPB children are still at risk for serious morbidities like chronical lung disease and neurodevelopmental impairment. Patent ductus arteriosus (PDA) occurs in about half of EPB children and 20-30% undergo surgical ligation of the PDA, a procedure which unfortunately leaves the n. recurrens at risk.

The WestPaedResearch at the children’s clinic, Haukeland University Hospital, are following three population-based cohorts of EPB children born between 1982-1985, 1991-1992 and 1999-2000.

During examination of all PDA ligated children in the regional cohort from 1982-1985, 64% (N=7/11) of the children were diagnosed with paresis of n.recurrens, which leads to paresis of the left side of the larynx. 

Reports of prevalence of damage to the n. recurrence during PDA surgery varies between studies; however, 64% is a high occurrence of paresis of n.recurrens compared to other studies. In our national cohort PEP 99-00, 51 children underwent surgical ligation of PDA, and the occurrence of paresis of n.recurrens in this cohort is unknown. Knowledge about short-and especially long-term consequences of paresis of n.recurrens after PDA surgery is limited.

The aim of this study is to investigate the prevalence and consequences of paresis of n.recurrens after PDA surgery in EPB children. 

The aim of this study is to investigate the prevalence and consequences of paresis of n.recurrens after PDA surgery in EPB children. This study is conducted in cooperation between WestPaedResearch (EILO/Prematurity) at Haukeland University Hospital and the research group “Movement and Function” at Bergen University College.

PhD Fellow:

Merete Engeseth

Ongoing and/or planned projects


A systematic review investigating:

a )

Prevalence of n.recurrens paresis following surgical ligation of PDA in extremely premature born children 

b )

Short term- and long-term consequences following surgical closure of PDA in extremely premature born children.


Investigate whether there are differences between EPB children and term born children when it comes to physical activity level and endurance at 11 years of age.  We will use parental reported data from questionnaires regarding EPB children and controls from PEP- 99-00.


Find the prevalence of paresis of n.recurrens following PDA ligation in PEP 99-00. We will ask all 51 children from PEP-99/00 who underwent PDA-surgery during infancy to participate in the study. Data from lung function testing, laryngoscopic testing during exercise and laryngologic examination will be collected at Haukeland University Hospital.

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