Feasibility, technique and accuracy of ultrasound-guided transurethral injections into the urinary sphincter of female cadavers: proof of concept.
BACKGROUND
The injection of muscle precursor cells (MPC) into the external urinary sphincter muscle (EUS) is a promising therapeutic option for regenerative treatment of stress urinary incontinence (SUI). The objective of the present project was to conduct a pre-clinical trial to investigate the feasibility and accuracy of ultrasound (US) guided, transurethral injections into the EUS of female cadavers.


METHODS
This is a prospective, anatomical, interventional and radiological cadaveric laboratory investigation. Two urologists performed transurethral US-guided injections to deliver nano-iron particles into the EUS. The intervention was performed in three unfixed, fresh female cadavers. Each cadaver received MRI before and CT as well as MRI of the pelvis after the injections.


RESULTS
The precision and accumulation of nano-iron particles in the EUS was compared using a rating scale to evaluate left versus right and anterior versus posterior distribution in axial and sagittal orientation with US, MRI and CT. The accuracy of our US-guided injections into the anterior target region yielded 4 points on the rating scale. Adequate precision and accumulation of particles in the left versus right EUS were also demonstrated (3 vs. 3.33 points, respectively). Signal intensity in MRI revealed a mean ratio of 0.33 before and after injection. CT scans showed no relevant artefacts impairing the assessment.


CONCLUSION
US-guided, transurethral injection into the EUS is feasible and imaging reveals a precise accumulation in the target region. Our method provides an appropriate approach to deliver MPC in the EUS muscle for a regenerative treatment of SUI in the near future.
['Schmid|Florian A|FA|', 'Gascho|Dominic|D|', 'Zoelch|Niklaus|N|', 'Prange|Jenny A|JA|', 'Colacicco|Giovanni|G|', 'Eberli|Daniel|D|']
D002102:Cadaver D005240:Feasibility Studies D005260:Female D006801:Humans D007267:Injections D000075082:Proof of Concept Study D015203:Reproducibility of Results D018084:Ultrasonography, Interventional D014521:Urethra
Ultrasound-guided Transurethral injection Urinary sphincter Female MRI