Laparoscopic and open partial nephrectomy: Frequency and long-term follow-up of postoperative collections

Purpose: To compare imaging findings between laproscopic and open partial nephrectomy at 6 months after surgery and to follow the evolution of the findings over time. Materials and Methods: This HIPAA-compliant retrospective study had institutional review board approval and consent was waived. A surgical database was cross-referenced with an imaging database to identify patients who underwent partial nephrectomy and computed tomographic and/or magnetic resonance imaging within 6 months of surgery. Fifty-eight patients (mean age, 61 years; range, 34-78 years; 21 women, 37 men) underwent 62 partial nephrectomies (laparoscopic, 31; open, 31) to remove 68 masses. Two radiologists in consensus reviewed images obtained between 10 days and 72 months (mean, 28 months) after surgery. Preoperative mass size and location and postoperative kidney orientation, fat stranding, parenchymal defect, collection (including size, location, and appearance), and other complications were recorded. Relative incidence of postoperative imaging findings, demographics, and initial imaging findings of both groups were statistically assessed by using Student t and x² tests corrected for multiple comparisons. Results: Common imaging findings following surgery included kidney displacement (48% [30 of 62]), perinephric fat stranding (93% [63 of 68]), parenchymal defect (74% [50 of 68]), and a non-fat-containing postoperative collection 75%, with significantly more posterior renal displacement (P < .01) and a trend toward more persistent fat stranding in the open surgery group. Fifty-one collections were identified in 74% (43 of 58) of patients, with significantly more collections in the laparoscopic (90% [27 of 30] vs 55% [16 of 29]; P < .05). The proportion of resolved collections increased over time, with significantly more resolving in the open group within 24 months of surgery (P < .05). Development or resolution of a collection was not dependent on age, sex, preoperative lesion size, or location (P > .05). Conclusion: Prevalence of findings 2-3 years after partial nephrectomy depends on the surgical approach. After laparoscopic partial nephrectomy, collections are more frequently detected on images and may take longer to resolve than following an open approach.