Flank Bulging and Sensory Disturbances After Open Renal Surgery Through Lumbotomy: Clinical Phenotypes and Procedure-Related Associations

Background and Objectives: Flank bulging is a recognized consequence of open renal surgery through a lumbotomy, but its clinical relevance and relationship with postoperative sensory changes are not well defined. We assessed the frequency and clinical burden of postoperative flank bulging, its overlap with sensory disturbances, and procedure-related factors associated with its occurrence. Materials and Methods: We reviewed 407 patients who underwent open renal surgery through a subcostal lumbotomy between 2018 and 2023. Flank bulging was the primary outcome. We also recorded scar hypoesthesia, wider areas of sensory loss, and whether patients found the resulting deformity bothersome. Factors associated with bulging were explored using multivariable logistic regression, with a separate analysis comparing nephron-sparing surgery (NSS) and radical nephrectomy.