Pilot study evaluating ureteric physiological changes with a novel ‘ribbon stent’ design using electromyographic and giant magnetoresistive sensors

• Published in: BJU international Vol. 103; no. 8; pp. 1128 - 1131
• Main Authors: Natalin, Ricardo A., Hruby, Gregory W., Okhunov, Zhamshid, Singh, Harmanmeet, Phillips, Courtney K., Humphrey, Peter A., Gupta, Mantu, Landman, Jaime
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-04-2009; Wiley-Blackwell
• Subjects: Analysis of Variance; Animals; Biological and medical sciences; Electromyography; Female; Magnetics; Medical sciences; Nephrology. Urinary tract diseases; Peristalsis - physiology; Pilot Projects; Prosthesis Design; Stents; Swine; Ureter - physiology; ureteric physiology; ureteric stent; Electrodiagnosis; Endoprosthesis; Nephrology; ureteric stent; Electrophysiology; Instrumentation therapy; ureteric physiology; Electromyography; Physiology; Ureter; Stent; Urology
• ISSN: 1464-4096; 1464-410X
• DOI: 10.1111/j.1464-410X.2008.08184.x

OBJECTIVE
To test a novel ‘ribbon stent’ (RS) design using an extraluminal bipolar electromyographic (EMG) and giant magnetoresistive (GMR) sensor system to characterize ureteric responses.
MATERIALS AND METHODS
In all, 11 female domestic pigs were divided into three groups to evaluate ureteric physiology: group 1 (two pigs) with an unstented ureter, group 2 (three) with a standard 6 F ureteric stent, and group 3 (six) with the RS. For all groups EMG/GMR evaluation was performed at baseline, immediately after stenting, and at 3 and 7 days after stenting. All pigs underwent standardized retrograde ureteropyelogram evaluation at these time points, and after the final evaluation the pigs were killed and the urinary tract was harvested for histopathological evaluation.
RESULTS
One stent in group 3 could not be deployed due to a problem with ureteric access. For groups 1, 2 and 3 the ureteric peristaltic activity was 109, 63, 72 events/h at baseline (P = 0.49); 61, 70, and 66 events/h immediately after stenting (P = 0.97); 66, 0, 8 events/h at 3 days after stenting (P = 0.002); and 61, 12, 0 events/h at 7 days after stenting, respectively (P = 0.049).
CONCLUSION
The RS was deployed easily and safely in the porcine model using a standard technique. As with a standard stent, there was significant ureteric dilation and decrease in peristalsis with the RS.