Polyacrylamide hydrogel (Bulkamid) is a relatively recent bulking agent which may have a better safety profile than previous generations. The objective of this study was to report our experience of outpatient peri-urethral injections of Bulkamid under local anesthesia in the office in female patients for stress urinary incontinence (SUI).

The data of all women who underwent outpatient peri-urethral Bulkamid injections under local anesthesia in the office at a single academic center were collected prospectively between November 2019 and August 2023. This therapeutic option was offered to patients who had SUI if > 80-year-old and/or had multiple comorbidities or if they declined all other therapeutic options.
Patients who underwent PAHG perirurethral injections in the operative room (OR) under spinal or general anesthesia were excluded from the present study.

Ninety-two patients were included. The mean age was 78 years (30-97). Twenty patients experienced postoperative complications (21%), nineteen were Clavien 1 complication, only one complication was Clavien = 4. 
Sixty-two injections yielded patients ‘satisfaction at 3 months according to the predefined primary endpoint, i.e. PGI-I ≤ 2 (60.2%).
At 3 months there was a statistically significant improvement in all USP subscores : the USP SUI subscore decreased from 6.8 to 3.5 (p<0.0001), the USP OAB subscore decreased from 11 to 8.2 (p<0.0001) and the USP voiding symptoms subscore decreased from 1.2 to 0.9 (p=0.04). The mean ICIQ-SF
decreased significantly from 15.2 at to 8.1 at 3 months (p<0.0001). The mean PVR remained stable at 3 months (6 ml vs 11.8 ml at baseline; p=0.12) but there was a statistically significant decrease in Qmax (16.1 ml/s vs. 18.9 ml/s at baseline; p=0.008). 
After a median follow-up of 7 months (range 3 to 35), 61 patients still met the criteria for success (i.e. PGI-I ≤ 2; 59.2%).
The VAS for urethral coaptation self-assessed by the surgeon at the end of the procedure was the strongest predictor of postoperative outcomes.

Although the treatment of female SUI has improved dramatically over the past decades, the recent mesh controversy along with the growing elderly population and the shift towards a more patient-centered approach rooted in shared-decision making has spurred the medical community to explore alternatives to the gold standard treatment like midurethral slings, Burch colposuspension and fascial pubovaginal slings. Bulking agents have been used for over two decades but the emergence of non-particulate agents such as PAHG, which may have a better safety profile, has reignitied interest in this treatment option. In the present series, we demonstrated the feasibility of outpatient PAHG periurethral injections in the office employing a simplified protocol of local anesthesia with satisfactory functional outcomes and an excellent safety profile

Future studies exploring the learning curve of PAHG periurethral injections may be of great interest to deepen our findings.

Our study confirms the excellent safety profile of PAHG periurethral injections. Although a large proportion of our patients were frail and elderly with multiple comorbidities, the rate of postoperative complications was low with only one severe complication (hyponatremia). Most importantly, none of these complications lasted for long and none caused sequelae beyond three months. One of the concerns with bulking agents is that they may create bladder outlet obstruction. No patients in the present series required self-catheterization in the long run and the PVR did not increase significantly. Short indwelling urethral catheterization is enough to resolve acute urinary retention, probably by crushing PAHG.

These options may be of great value in frail patients and those looking for a minimally invasive treatment. The local anesthesia protocol with the office setting may be of particular interest in current times with challenging access to the operative room in many institutions. Other studies are needed to confirm these findings.