Significance of extraction forces in kidney stone basketing - Abstract

Ureteroscopic stone extraction devices are effective tools in the management of urolithiasis, but on occasion their improper use can cause injury to the ureter.

Avulsion and perforation of the ureter as a result of excessive forces on the extraction device are some of the more serious complications of this treatment. In this paper, avulsion and perforation forces were measured by two different test setups. Eleven clinicians were asked to apply three ranges of forces (safe, cautious and dangerous). The output force measurements were recorded and plotted for further analysis. The maximal average perforation forces were 7.13 ± 2.36 N in the bench top tests and 7.07 ± 2.20 N in the ex-vivo porcine tests (P = 0.54). The maximal average avulsion forces were measured to be 10.14 ± 2.01 N in the bench top tests. Although the average forces were similar in the proximal and distal parts of the ureter (P = 0.27), higher values were recorded for the distal part. The operation time was noted to be significantly different in the safe and cautious force regions (P= 0.006). The average forces were higher in the bench top tests as compared to the porcine ureter tests. The extraction forces were measured and were noted to be significantly different for attendings and residents. The results suggest the need for force feedback training to residents. The findings can be used to design a "smart device" that can provide visual force feedback to clinicians while they are operating, leading to improved patient outcome.

Written by:
Najafi Z, Tieu T, Mahajan AM, Schwartz BF.   Are you the author?
The University of Akron, Department of Biomedical Engineering, Akron, Ohio, United States; Southern Illinois University School of Medicine, Division of Urology, Springfield, Illinois, United States.  ; ; ;

Reference: J Endourol. 2015 Jun 9. Epub ahead of print.
doi: 10.1089/end.2015.0371

PubMed Abstract
PMID: 26054796 Endourology Section