BackgroundTo investigate the efficacy and safety of endoscopic electrocoagulation haemostasis via a percutaneous transhepatic approach for the treatment of grade IV haemorrhagic cystitis (HC) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) in children.MethodsThe clinical data of 14 children with severe HC, who were admitted to Hebei Yanda Hospital between July 2017 and January 2020, were analysed retrospectively. There were nine males and five females, with an average age of 8.6 years (range: 3 to 13 years). After an average of 39.6 (7 to 96) days of conservative treatment in the hospital’s haematology department, the bladders of all patients were filled with blood clots. A small 2-cm incision was made in the suprapubic area to enter the bladder and quickly clear the blood clots, and a percutaneous transhepatic approach to electrocoagulation and haemostasis was performed.ResultsIn the 14 children, a total of 16 operations were performed, with an average operation time of 97.1 (31 to 150) min, an average blood clot of 128.1 (80 to 460) mL and an average intraoperative blood loss of 31.9 (20 to 50) mL. There were three cases of postoperative bladder spasm remission after conservative treatment. During the follow-up period of 1 to 31 months, one patient improved after one operation, 11 patients were cured after one operation, and two patients were cured after recurrent haemostasis by secondary electrocoagulation, four of whom died of postoperative non-surgical blood-related diseases and severe lung infections.ConclusionPercutaneous electrocoagulation haemostasis can quickly remove blood clots in the bladders of children after allo-HSCT with grade IV HC. It is a safe and effective minimally invasive treatment.