The Effects of TTNS, TTNS Combined With PHUS, and Conventional Therapy With PHUS in the Treatment of PFC.

Inclusion Criteria Children aged 4 to 14 years Clinical diagnosis of functional constipation (FC), with no identifiable organic or anatomical cause (e.g., endocrine, metabolic, anatomical, or neuromuscular dysfunction) FC diagnosis established according to Rome IV criteria No additional tests required to confirm eligibility Ability to complete daily diaries and TTNS sessions (by participant or caregiver) Failure of conservative medical treatment (including toilet training and laxatives) after at least three months Exclusion Criteria Malformations of the digestive system and rectal anatomical anomalies (e.g., large intestinal atresia/stenosis, Hirschsprung's disease, congenital anorectal anomalies) Neurological or psychiatric disorders (e.g., cerebral palsy, spina bifida, intellectual disability, anorexia nervosa) Major cognitive impairment Metabolic conditions (e.g., diabetes mellitus, diabetes insipidus, scurvy, phenylketonuria) Endocrine disorders (e.g., hypothyroidism) Cardiac conditions (e.g., heart disease, arrhythmias, presence of pacemaker or ventriculoperitoneal shunt) due to possible interference with electrical stimulation History of thoracic or abdominal surgery Presence of skin lesions in the area of electrode application Presence of active electronic implants