Table 2

Criteria for AS, the procedure, and the outcome of the studies included

Authors	Inclusion criteria	Exclusion criteria	AS procedure	Outcomes
Haworth5	Only true umbilical hernia.	Babies whose hernias had previously been kept efficiently reduced. Supraumbilical hernia, linea alba hernia, babies with cutis navel, Asian, hypothyroidism, and general muscular hypotonia. Infants felt excessive discomfort or soreness of the skin during application of AS (2 cases).	The skin was first painted with tincture of benzoin. Using two pieces of nonelastic plaster (2 inches) and threading a tongue cut in one through a hole cut in the other. The assistant reduced the hernia by pinching the skin into a vertical fold over the hernia and the plasters were pulled tight. Another plaster (3 inches) was applied over the plasters. Strapping was kept for 4 weeks. Strapping was renewed for a further 2 weeks and continued (maximum 8 weeks).	Efficacy of AS at age 12 months. Efficacy depending on the size of protrusion and defect size. Relation between efficacy and the age at which AS was applied. Complications.
Karlström9	Umbilical hernia treated during a 2.5-year period.	Hernia of which healing had not taken place at the time of the investigation. Patients who had not been kept under sufficiently strict observation.	Hernia was restored and the skin was drawn tightly together into a longitudinal fold over the umbilical ring and held in this position with an approximately 5 cm wide elastic plaster band, which extended as far as the axillary line. The plaster was changed by the author or by nurses before it fell off or when it had begun to loosen at the edges. Only when the skin was extremely irritated was it allowed to rest for a few days before a new plaster was applied.	Efficacy of AS by the age of 4 months, 6 months, and 1 year according to the size of the hernia defect.
Halpern10	Every infant who attended the author’s clinic within the time limit (1950s) and had an umbilical hernia.	NR.	AS was applied in deference to parental insistence. Elastic tape was used. Return visits were scheduled for every 2 weeks during the first 6 months of life, every month during the remainder of the first year, every 3 months during the second year, and every 6 months thereafter.	Efficacy of AS according to the size of protrusion and defect size.
Angel-Lord11	Congenital umbilical hernia. Baby’s age must initially be ≤12 months. There must be a visual and palpable protrusion. There must be a palpable gap in the linea alba. The hernia must be digitally reducible.	Paraumbilical hernia, Asian, and children with any apparent chronic illness.	A single piece of zinc oxide plaster (nonelastic) 2–3 inches wide was applied across the abdomen from flank to flank. The protrusion was reduced by digital pressure only and there was not folding of skin across the hernia site. Children were observed every 3 or 4 weeks for at least 12 months. Strapping was renewed by the author or the baby health center sister when it became too dirty or water-logged or peeled from the edges, without a definite time set for renewal.	Efficacy of AS.
Oshio et al2	Umbilical hernia treated at institute A (control group) and those at B (AS). Birth weight over 1500 g. Children aged ≤6 months.	NR.	A cotton ball was placed after hernia reduction. Skin was drawn tightly over the umbilicus and then elastic bandage (5×12 cm) was placed over the umbilicus. The bandage was renewed every week. When skin had severe inflammation, new bandage was applied after a few days of rest period.	Efficacy of AS and the duration until the hernia was healed.
Kanada et al14	Infants aged <6 months and followed up to age 2 years. AS group included babies who visited from October 2000 to January 2005. Control group included babies who visited before December 2002.	NR.	After hernia reduction, a bandage was placed after skin was drawn tightly over the umbilicus. The bandage was renewed by guardians every 2–3 days at home.	Efficacy of AS and the duration until the hernia was healed.
Hiraoka20	Infants treated by AS for a 3-year period from September 2010.	Babies who dropped from follow-up visit.	A resin plug was placed on the umbilicus and a plaster (10×6 cm) was placed. The plaster was renewed every week. If protrusion was not observed twice in a row, another plaster was renewed for 1 week and treatment was completed.	Frequency of umbilical hernia. Efficacy of AS according to the defect size.
Hayashida et al21	Babies referred from April 2011 to December 2015.	Babies who had a coexisting disease that required surgery, those transferred to another hospital, and those who were lost to follow-up.	After hernia reduction, a cotton ball matching the size of the hernia orifice was inserted and fixed in place using elastic adhesive plaster.	Efficacy of AS. Comparison between success group and failure group in AS group. The effect of AS on the difficulty of surgery and operation time among infants whose treatment failed.
Kurobe et al16	Control group included infants observed from January 2006 to December 2008. AS group included infants treated from January 2010 to December 2014.	NR.	After hernia reduction, a small sponge was inserted and the fold of skin from two sides was brought together, forming a single crease. Covering the sponge, an elastic adhesive tape was placed. The tape was renewed every week by guardians.	Efficacy of AS. Complication and limitation of AS.
Kitano et al17	Babies aged ≤6 months at the first visit from 2012 to 2015.	Infants with trisomy 21, hypothyroidism, muscle disease, congenital heart disease, hypospadias, spina bifida, meningocele, and mucopolysaccharidosis. Birth weight <1500 g.	After hernia reduction, a small gauze or cotton wool matching the size of the hernia was inserted. Then, the fold of skin from two sides was brought together to cover the plug. An elastic adhesive plaster was placed. A transparent waterproof film dressing was placed over the plaster. The tape was renewed every week by guardians.	Efficacy of AS.

AS, adhesive strapping; NR, not reported.