Open partial nephrectomy with kidney split: Effective surgical approach to resect completely endophytic tumors

Objectives: To review perioperative, renal functional, and oncological outcomes of the kidney split technique in performing partial nephrectomy (PN) to resect completely endophytic renal tumors. Methods: All consecutive patients who underwent open PN with kidney split between 2015 and 2019 at our institution were included. In this approach the kidney is incised along Brodel's line in an avascular plane to locate and then resect the endophytic tumor. Clinicopathologic data, perioperative metrics, complications, renal function, recurrence, and mortality were analyzed using descriptive statistics. Results: Forty-two open PN with kidney split were performed in 40 patients. No patients required conversion to radical nephrectomy. Most tumors were pT1a renal cell carcinoma (76%), with no recurrences or deaths after a median follow-up of 15 months. All patients had tumors of moderate or high complexity by R.E.N.A.L. nephrometry score. Median cold ischemia time, operative time, estimated blood loss, and inpatient length-of-stay were 34 minutes, 152 minutes, 225 ml, and 2 days, respectively. No patients experienced any Clavien-Dindo grade 4 or 5 complications. Postoperative estimated glomerular filtration rate (eGFR) at last follow-up was >30 ml/min/1.73m² in all but one patient, and no patients required dialysis. Conclusions: The kidney split represents an effective PN technique to resect complex, endophytic renal tumors. In our experience, this technique affords acceptable perioperative outcomes, preserved renal function, and no short-term recurrences or mortality events. Our series highlights the importance of adapting classical surgical techniques, using cold ischemia, and relying on preoperative and intraoperative ultrasonography to effectively guide this complex kidney-sparing operation.