Application of virtual endoscopic imaging to parapelvic cyst incision by flexible ureteroscopy: a multicenter retrospective cohort study.

Background: A three-dimensional (3D) reconstruction of the kidney, parapelvic cyst and the collecting system was conducted using the 3D Slicer software. The reconstructed image was used to form a virtual endoscope to assist flexible ureteroscopic incision and drainage was performed with a holmium laser for treating parapelvic cysts. The effectiveness of this assistive technique was assessed.

Methods: This was a retrospective cohort study. The clinical information of 59 patients undergoing flexible ureteroscopic incision and drainage for parapelvic cysts in two medical centers was collected. 3D Slicer software reconstruction and virtual endoscopic imaging were performed for 28 cases. Before the operation, the best point for incision on the collecting system's mucosa was assessed by virtual endoscope imaging. Propensity score matching was adopted for the reconstructive and non-reconstructive groups.

Results: After matching, the reconstructive group and non-reconstructive group both had 21 cases each. The operation time in the reconstructive and non-reconstructive groups was 38.81±5.01 and 51.00±18 minutes, respectively. Statistically significant differences existed between the two groups (t=7.024, P<0.001). No statistical significance was found in postoperative fever, immediate postoperative C reactive protein (CRP), length of postoperative hospital stay and cyst diameter three months after the operation.

Conclusions: The operator was provided with a more direct and real vision when 3D Slicer software reconstruction was adopted via virtual endoscopic imaging to assist flexible ureteroscopic parapelvic cyst incision. This helped reduce the operation time. Further follow-ups and observations are required to assess the long-term efficacy of flexible ureteroscopic parapelvic cyst incision.