When scoliosis surgery in a child unexpectedly resolves hydronephrosis: A case report and review of the literature.

Hydronephrosis, defined as dilation of the renal pelvis and calyces, may occur with scoliosis or after corrective surgery. However, spontaneous resolution of pre-existing hydronephrosis following scoliosis correction has not been previously reported. We present a 12-year-old girl with a ZMYM2 mutation, severe thoracolumbar scoliosis (Cobb 103°), and bilateral hydronephrosis. After posterior spinal fusion (T4-L3), hydronephrosis resolved completely. Just as the spinal angle, likely the angle between the renal pelvis and ureter was similarly adjusted, facilitating improved urinary drainage. This rare case highlights a possible dual therapeutic effect of scoliosis correction on spinal alignment and urinary drainage in selected cases.