EFFECT OF ULTRASOUND-GUIDED ERECTOR SPINAE PLANE BLOCK ON POSTOPERATIVE PAIN IN PATIENTS UNDERGOING OPEN NEPHRECTOMY AND PYELOPLASTY: A SINGLE-CENTER OBSERVATIONAL STUDY. Greenfort International Journal of Applied Medical Science, [S. l.], v. 4, n. 2, p. 65–70, 2026. DOI: 10.62046/gijams.2026.v04i02.005. Disponível em: https://gijams.in/index.php/gijams/article/view/104. Acesso em: 23 may. 2026.