Presented by: Anne Hong MD
Austin Health

Introduction

Raised intrarenal pressure (IRP) during ureteroscopy has been attributed to infectious complications. To study this, we assess intrarenal pressures in human subjects using pressure guidewire technology.

Materials

Patients undergoing ureteroscopy for urolithiasis were recruited to the present study. During the procedure, the pressure guidewire was used for all pressure measurement. The pressure guidewire was inserted with the pressure sensor positioned in the renal pelvis at the beginning of the procedure. The remainder of the procedures were performed without deviation from usual. The operating surgeon was blinded to the live intrarenal measurements. The primary outcome was infective complications. Secondary outcomes include ipsilateral flank pain. Maximal IRPs were also recorded.

Results

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Results:

44 patients who underwent 47 procedures were included. The mean age was 52 years and 32 (73%) were male patients. 3 (7%) had long term urinary catheters.

There were 7 proximal ureteric stones, 3 pelviureteral junction stones and 37 intrarenal stones. Of the procedures, 17 (36%) had pre-operative positive urine culture and was managed with antibiotics. 26 (55%) of procedures had pre-existing ureteric stents. Intra-operatively, 36 (77%) of procedures used an access sheath. The mean IRP at rest (with wires only) was 18mmHg. The mean of the maximal IRPs achieved during manipulation was 128mmHg.

A total of 8 procedures (19%) deviated from routine post operative care. 2 cases (4.2%) experienced hypotension immediately post operatively without other features. 3 cases (6%) resulted in infective symptoms. 3 cases (6%) presenting to the emergency department with severe flank pains. Pooling the IRP data of all 8 cases, the average and maximum IRPs were higher than those who did not experience any complications – at 37 vs. 32mmHg and 135 vs. 128 mmHg, although these were not statistically significant.

Conclusion

IRPs are highly susceptible to manipulation during ureteroscopy, increasing from 18mmHg to 128mmHg in our study. These elevated pressures may put patients at risk of complications, as demonstrated by our patient cohort.

Funding

This study was funded by Boston Scientific with a grant via the Investigator Sponsored Research Program. 

Lead Authors

Cliodhna Browne, MD
Austin Health

Greg Jack, MD, PhD
Austin Health

Damien Bolton, MBBS, PhD
Austin Health