X-Capsular Incision for Tumor Enucleation (X-CITE)-Technique: A method to maximize renal parenchymal preservation for completely endophytic renal tumors.

OBJECTIVES To describe the X-Capsular Incision for Tumor Enucleation (X-CITE) technique to resect endophytic renal tumors while preserving the overlying renal parenchyma. SUBJECTS AND METHODS We reviewed one-year outcomes of 12 consecutive patients with a history of bilateral or multifocal renal tumors who presented to our institution with completely endophytic renal masse(s) between August 2017 and August 2018. Endophytic tumors were resected by making X-shaped incision was made in the renal capsule and developing parenchymal flaps overlying the tumor pseudocapsule. Following tumor enucleation, the overlying parenchymal flaps were reapproximated. RESULTS Median follow up was 19.9 months (range 10.6-14.9). Most patients also had additional exophytic tumors and on average, 5 renal tumors were removed per operation with a median largest renal tumor size of 3.2cm. No intraoperative or postoperative complications occurred. There was no decline in renal function after surgery when comparing median pre- and 12-month post-operative eGFR (94.5 vs 91.5, p=0.18).). Postoperative nuclear MAG-3 renal scans demonstrated equal differential kidney function after surgery. Limitations include short-term follow-up and referral bias at center specializing in multi-focal kidney surgery. CONCLUSION The X-CITE technique is feasible, safe and effective with minimal collateral damage in the treatment of completely endophytic renal masses. Further investigation should identify which patients may benefit from this procedure and explore intermediate and long-term outcomes.