Application of Contrast-Enhanced Ultrasonography (CEUS) in the Assessment of Kidney Wound Recovery After Nephron-Sparing Surgery

PURPOSE: To investigate feasibility, repeatability and usefulness of contrast-enhanced ultrasonography (CEUS) in the assessment of kidney wound recovery after laparoscopic nephron-sparing surgery (LNSS) or robot-assisted nephron-sparing surgery (RANSS) and preliminarily research the clinical factors associated with the length of extravasation (LOE). PATIENTS AND METHODS: From April 2019 to January 2020, 130 patients that underwent LNSS or RANSS in our hospital were included, and 90 patients (90/130) received CEUS examinations each one day from the postoperative day 1. The discovery of the cessation of contrast medium extravasation from the renal wound was the primary endpoint named “ultrasonic healing”, and LOE ranged from the day of surgery to “ultrasonic healing”. Patient, tumor, perioperative factors and LOE were collected. Univariate analysis and multivariate linear regression analysis were applied for the determination of factors associated with LOE. RESULTS: The average postoperative LOE was 1.76 days (standard deviation, 1.115; 95% confidence interval: 1.52–1.99). Ultrasonic healing within three days was observed in 95.6% patients (86/90). Univariable and multivariable analyses showed that R and A components in R.E.N.A.L. nephrometry score were associated with LOE. Anterior location and R component score of 2 (tumor size>4cm) were related to longer LOE than posterior location and R score of 1 (tumor size<4cm). The incidence of complications in patients with LOE over one day was higher than those with LOE of one day. CONCLUSION: CEUS was feasible, repeatable and useful in the assessment of kidney wound recovery. Tumor size and location were related to LOE after minimally invasive nephron-sparing surgery (MINSS). Length of stay after MINSS within three days might be relatively safe.