Periventricular leukomalacia and neurodevelopmental outcome

Periventricular leukomalacia and neurodevelopmental outcome To the Editor: Cystic periventricular leukomalacia (c-PVL) is a severe complication of preterm birth leading to cerebral palsy in most afflicted children. Despite distinctions in research groups using different classification systems in different cohorts, the incidence of c-PVL is reported to range from 3% to 10%.1 We read with interested the article by van Haastert et al2 reporting a decrease in the incidence and severity of cerebral palsy in a 16-years period (1990-2005) that could be attributed to a reduction of 93% in severe c-PVL. The study confirms US data from Hamrick et al3 who first reported on a decline in c-PVL that was not associated at that time with improved developmental outcome during an 11-years observation period from 1992 to 2002. Our own data collected from 1988 and 2008 revealed 145 of a total of 6200 preterm infants (2.34%) #35 weeks gestational age (median gestational age, 30.8 weeks; median birth weight, 1441 g) had c-PVL with cranial ultrasound scanning. There was a mean incidence rate of 3.1% (98/3187 infants), varying between 1.0% and 5.8% per year, during observational period 1 (1988-1998), compared with 1.5% (59/3103 infants, P = .0014) during period 2 (1999-2008), varying between 0.9% and 2.9%. Some perinatal data changed significantly during these two periods (Table), with some similarities compared with the data of van Haastert et al.2 With neurodevelopmental follow-up, unchanged rates of cerebral palsy (78.6% versus 81.4 %, P = .467) that are in accordance with Hamrick et al,3 but significantly reduced rates of mental retardation (61.2% versus 30.5%, P < .0001) were revealed. The latter seems Table. Perinatal data of preterm infants with c-PVL diagnosed with cranial ultrasound scanning revealing significant differences by comparison of two periods, 1988 to 1998 and 1999 to 2008 Perinatal data

1988-1998 (n = 98)

1999-2008 (n = 47)

P value

Gestational age, weeks Male sex History of abortion PPROM Chorioamnionitis Cesarean delivery Maternal steroids Maternal antibiotics Apgar score 5 minutes Apgar score 10 minutes Early-onset sepsis Hyperbilirubinemia IVH/PVH RDS Neonatal seizures

31  2.5 (26-35) 66 (67) 13 (13) 58 (59) 48 (49) 43 (44) 19 (19) 13 (13) 8.9  1.1 (6-10) 9.4  0.9 (5-10) 49 (50) 51 (52) 47 (48) 44 (45) 30 (31)

30  2.2 (25-35) 25 (42) 19 (32) 23 (39) 17 (29) 37 (63) 25 (42) 27 (46) 8.3  1.4 (3-10) 8.8  1.2 (5-10) 14 (24) 21 (36) 16 (27) 39 (66) 4 (7)

.024 .001 .003 .009 .008 .008 .029 .004 .002 <.001 .001 .023 .005 .003 <.001

PPROM, preterm premature rupture of the membranes; IVH/PVH, intraventricular/periventricular hemorrhage; RDS, respiratory distress syndrome (with surfactant replacement therapy). Data are presented as number (percentage) or mean  SD (range).

highly impressive, but has to be regarded with caution because of the shorter follow-up time of the infants during the second period. Location of cysts as described elsewhere4,5 did not reveal differences, but mean diameters of the largest single cysts decreased (12.2 versus 8.4 mm, P = .005), and cysts were diagnosed earlier during period 2 (22 versus 19 days, P = .046). In conclusion, reasons for and associations with the decline in c-PVL remain speculative.

Bernhard Resch, MD Research Unit for Neonatal Infectious Diseases and Epidemiology Division of Neonatology and Outpatient Clinic of Neurodevelopmental Follow-up Department of Pediatrics and Adolescent Medicine Elisabeth Resch, MS Research Unit for Neonatal Infectious Diseases and Epidemiology Ute Maurer, MD Wilhelm Mueller, MD Division of Neonatology and Outpatient Clinic of Neurodevelopmental Follow-up Department of Pediatrics and Adolescent Medicine Medical University of Graz Graz, Austria 10.1016/j.jpeds.2011.08.025

References 1. De Vries LS, Rennie JM. Preterm brain injury: periventricular leukomalacia. In: Rennie JM, ed. Roberton’s textbook of neonatology. 4th ed. Philadelphia, PA: Elsevier Limited; 2005. p. 1159-64. 2. van Haastert IC, Groenendaal F, Uiterwaal CS, Termote JU, van der Heide-Jalving M, Eijsermans MJ, et al. Decreasing incidence and severity of cerebral palsy in prematurely born children. J Pediatr 2011;159:8691.e1. 3. Hamrick SEG, Miller SP, Leonard C, Gudden DV, Goldstein R, Ramaswamy V, et al. Trend in severe brain injury and neurodevelopmental outcome in premature newborn infants: the role of cystic periventricular leukomalacia. J Pediatr 2004;145:593-9. 4. Resch B, Vollaard E, Maurer U, Haas J, Rosegger H, Mueller W. Risk factors and determinants of neurodevelopmental outcome in cystic periventricular leukomalacia. Eur J Pediatr 2000;159:663-70. 5. Resch B, Jammernegg A, Vollaard E, Maurer U, Mueller WD, Pertl B. Preterm twin gestation and cystic periventricular leucomalacia. Arch Dis Child Fetal Neonatal Ed 2004;89:F315-20.

Reply To the Editor: We thank Resch et al for sharing their data with us, showing a very similar decline in the incidence of cystic periventricular leukomalacia (c-PVL), from 3.1% to 1.5%, covering 1049