O2181: Short Term Success and Complication with Extraction String After Robotic Pyeloplasty

Background: Robotic pyeloplasty is believed to offer benefits over open pyeloplasty: including decreased length of stay, less pain and smaller incisions. We sought to review our experience of preplacing a ureteral stent with an extraction string to obliviate the need for a secondary anesthetic for stent removal and decrease care burden on the family. We hypothesis use of an external string does not increase the risk of immediate postoperative urinary tract infections (UTIs) or complications.

Methods: We retrospectively reviewed all robotic pyeloplasty from 2012 – present done in our institution, we excluded patients without at least 60 days of follow-up. We compared patients with an extraction string to those with an indwelling stent. Our primary outcome of interest was incidence of urinary tract infection, secondary outcomes include immediate (within 60 days) complications and inadvertent stent removal. Demographics and clinical information was abstract from the patient charts. Statistical analysis was carried out using Fisher’s exact and two-same t-test.

Results: A total of 170 patients underwent robotic pyeloplasty during the study period: 135 had a stent with extraction string and 21 had an internal stent. Cohorts were similar in terms of age, gender, race, weight, presentation, grade of hydronephrosis prior to surgery, etiology of obstruction and length of stay.
A total of 14 patients in the entire series required treatment for UTI after discharge. Seven patients were treated on an outpatient basis for UTI (6 string (4.4%) vs 1 non-string (4.8%), p=0.64). Seven patients were admitted for treatment of UTI (7 string (5.2%) vs 0 non-string (0%), p=1). In subgroup analysis of string-cohort patents requiring outpatient treatment for UTI, 83% (5/6) were female. Of string-cohort patients requiring admission for UTI, 63% (5/8) were female.
Total number of complications was similar between the two groups (30 vs. 7, p=0.53). There were a total of 10 (7.4%) Clavien 3 complications in the string group. Three patients in this group underwent a percutaneous nephrostomy tube (2 for clot obstruction, 1 for stent dislodgement) and 3 underwent stent replacement (2 due distal ureteral edema, one due to urine leak).No Clavien 3 complications were noted in the internal stent group.

Six of 135 string patients required OR for stent removal (4.4%), 12 came to the office removal (8.9%) and all of the internal stent placement group required removal under anesthesia in the operating room.

Conclusion: Use of an extraction string in our single-institution series over a seven-year period showed similar rates of complications compared with internal stent placement. Complications and UTI rates are similar to published rates in series using antegrade stent placement. Retrograde stent placement with extraction string provides an equivalent outcome in terms of complications and greatly reduces the need for OR stent removal.