Evaluating the Ergonomics of Flexible Ureteroscopy

Wesley W. Ludwig, Gyusung Lee, Justin B. Ziemba, Joan S. Ko, Brian R. Matlaga

Research output: Contribution to journalArticlepeer-review


Introduction: To date the ergonomics of flexible ureteroscopy (URS) have not been well described. We performed a study to assess the biomechanical stresses on urologists performing URS and to investigate the effect of ureteroscope type on these parameters. Methods: Electromyography (EMG) was used to quantify the activation level of muscle groups involved in URS. Surface EMG electrodes (Delsys, Boston, MA) were placed on the right and left thenar, flexor carpi ulnaris (FCU), extensor carpi ulnaris (ECU), biceps, triceps, and deltoid. Three endoscopes were studied: single-use digital (Boston Scientific LithoVue), reusable digital (Karl Storz Flex-Xc), and reusable fiber-optic (Karl Storz Flex-X2). Each ureteroscope was used to perform a set sequence of navigation and procedural tasks in a training model. EMG data were processed and normalized to compare the maximum voluntary contractions between muscle groups. Cumulative muscular workload (CMW) and average muscular work per second (AWS) were used for comparative analysis. Results: For navigational tasks, CMW and AWS were greatest for the ECU, followed in descending order by right and left thenar, FCU, biceps, deltoid, and triceps. For procedural tasks CMW and AWS were greatest for the right thenar, followed in descending order by the left thenar, ECU, FCU, triceps, biceps, and deltoid. During navigational tasks, both LithoVue and Flex-Xc had lower CMWs for every muscle group than Flex-X2 (p < 0.05). LithoVue and Flex-Xc had similar AWS and both were lower than Flex-X2 for the right thenar, ECU, biceps, and deltoid activation (p < 0.05). During procedural tasks, both LithoVue and Flex-Xc had lower CMWs and AWS for right and left thenar, ECU, and biceps than Flex-X2 (p < 0.05). Conclusions: This study provides the first description of EMG-measured ergonomics of URS. Both the single-use and reusable digital ureteroscopes have similar profiles, and both have significantly better ergonomic metrics than the reusable fiber-optic ureteroscope.

Original languageEnglish (US)
Pages (from-to)1062-1066
Number of pages5
JournalJournal of Endourology
Issue number10
StatePublished - Oct 2017


  • electromyography
  • ergonomics
  • ureteroscopy
  • urolithiasis

ASJC Scopus subject areas

  • Urology


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