Evaluation Of Perirenal Anatomic Landmarks On Computed Tomography To Reduce The Risk Of Thoracic Complications During Supracostal Percutaneous Nephrolithotomy

Introduction: Supracostal access for percutaneous nephrolithotomy (PNL) has a known increased risk for thoracic complications (TCs). In this study, we perform a radiological review of preoperative and postoperative abdominal CT scans to assess the relationship of the upper pole of the kidney with surrounding landmarks to determine radiographic predictors of TCs.Methods: We performed a retrospective matched cohort comparison of patients who underwent supracostal PNL with and without TCs from 2012 to 2019. An experienced genitourinary (GU) radiologist reviewed pre- and postoperative CT scans to measure the craniocaudal distance between the upper renal pole and the most superior calix to the upper edge of the tip of the 12th rib, the costophrenic angle, and the posterior insertion of the diaphragm.Results: We identified 19 patients who developed TCs after undergoing PNL and compared their CT scans with 24 control patients without TCs. On a preoperative abdominal CT scan, the relationship of the upper edge of the renal parenchyma or upper pole calix with the superior edge of the tip of the 12th rib or costophrenic angle was not found to be predictive of TCs. On receiver operating characteristic analysis, diaphragmatic insertion of <= 2.5 cm below the upper edge of the renal parenchyma on sagittal and transverse views was predictive of TCs (p = 0.046). On postoperative CT scan, the percutaneous nephrostomy tract traversed the posterior insertion of the diaphragm in 80% of patients who had TCs compared with 20% of patients who had no TCs.Conclusions: The decreased distance between the posterior insertion of the diaphragm (medial and lateral arcuate ligaments) and the superior edge of the renal upper pole on preoperative CT scan was associated with TCs from supracostal puncture during PNL. Critical preoperative recognition of this anatomic relationship can help preoperative planning and patient counseling and may prevent or reduce TCs.