Workflow assessment as a preclinical development tool

Surgical process models of three techniques for minimally invasive cochlear implantation
  • Samuel MüllerEmail author
  • Lüder A. Kahrs
  • Johannes Gaa
  • Sebastian Tauscher
  • Marcel Kluge
  • Samuel John
  • Thomas S. Rau
  • Thomas Lenarz
  • Tobias Ortmaier
  • Omid Majdani
Original Article



Minimally invasive cochlear implant surgery is a challenging procedure due to high demands on accuracy. For clinical success, an according assistance system has to compete against the traditional approach in terms of risk, operating time and cost. It has not yet been determined what kind of system is the most suited. The purpose of this study is a proof of concept of surgical process modeling as a preclinical development tool and the comparison of workflow concepts for this new approach.


Three preclinical systems (two stereotactic and one robotic) for minimally invasive cochlear implant surgery are compared using the method of surgical process modeling. All three systems were successfully tested with ex vivo human specimen to create minimally invasive surgical access to the cochlea. Those systems where chosen for comparison, because they represent three diverse approaches with different corresponding workflows for the same intervention. The experiments were used to create a process model for each system by recording the interventions.


All three conceptual systems developed by our group have shown their eligibility. The recorded process models provide a convenient method for direct comparison. Reduction in the surgical time has a higher impact on the process, than time that is needed for setting up a system beforehand. The stereotactic approaches have little preparation effort and are low cost in terms of hardware compared to the robotic approach, which in return is beneficial in terms of workload reduction for the surgeon.


Surgical process modeling is suitable for comparison of different assistant systems for minimally invasive cochlear implantation. The benefit of reduced trauma, compared to the traditional mastoidectomy, can now be assessed with consideration of the workflow of each technique. The process models enable an assessment in the regard of surgical time and workload.


Surgical process model Minimally invasive surgery Cochlear implant Surgical robotics System evaluation 



The authors acknowledge the financial support by the Federal Ministry of Education and Research of Germany (BMBF Project Numbers 13GW0019C and 13GW0019E).

Compliance with ethical standards

Conflict of interest

The authors Tobias Ortmaier, Marcel Kluge, Samuel John, Thomas Rau, Omid Majdani and Thomas Lenarz declare being limited partners of HörSys IP GmbH & Co. KG that holds intellectual property regarding the RoboJigTM technology.

Ethical statement

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed consent

This articles does not contain patient data.


  1. 1.
    National Institues of Health (2010) Cochlear implants Pdfs/CochlearImplants(NIDCD).pdf. Accessed 12 Dec 2017 [Online]
  2. 2.
    World Health Organization, WHO (2017) Deafness and hearing loss Accessed 12 Dec 2017 [Online]
  3. 3.
    Balachandran R, Mitchell JE, Blachon G, Noble JH, Dawant BM, Fitzpatrick JM, Labadie RF (2010) Percutaneous cochlear implant drilling via customized frames: an in vitro study. Otolaryngol Head Neck Surg 142:421–426CrossRefGoogle Scholar
  4. 4.
    Kobler JP, Kotlarski J, Lexow GJ, Rau TS, Majdani O, Ortmaier T (2014) Design optimization of a bone-attached, redundant and reconfigurable parallel kinematic device for skull surgery. In: IEEE international conference on robotics and automation (ICRA), pp 2364–2371Google Scholar
  5. 5.
    Kobler JP, Kotlarski J, Öltjen J, Baron S, Ortmaier T (2011) Design and analysis of a head-mounted parallel kinematic device for skull surgery. Int J Comput Assist Radiol Surg 7:137–149CrossRefGoogle Scholar
  6. 6.
    Kobler JP, Nülle K, Lexow GJ, Rau TS, Majdani O, Kahrs LA, Kotlarski J, Tobias Ortmaier (2016) Configuration optimization and experimental accuracy evaluation of a bone-attached, parallel robot for skull surgery. Int J Comput Assist Radiol Surg 11:421–436CrossRefGoogle Scholar
  7. 7.
    Kratchman LB, Blachon GS, Withrow TJ, Balachandran R, Labadie RF, Webster RJ (2010) Toward automation of image-guided microstereotactic frames: a bone-attached parallel robot for percutaneous cochlear implantation. Robot Sci Syst Workshop Enabling Technol 31:94–99Google Scholar
  8. 8.
    Kratchman LB, Blachon GS, Withrow TJ, Balachandran R, Labadie RF, Webster RJ (2011) Design of a bone-attached parallel robot for percutaneous cochlear implantation. IEEE Trans Biomed Eng 58:2904–2910CrossRefGoogle Scholar
  9. 9.
    Labadie RF, Balachandran R, Mitchel JE, Noble JH, Majdani O, Haynes DS (2010) Clinical validation study of percutaneous cochlear access using patient customized micro-stereotactic frames. Otol Neurotol 31:94–99CrossRefGoogle Scholar
  10. 10.
    Labadie RF, Balachandran R, Noble JH, Blachon GS, Mitchell JE, Reda FA, Dawant BM, Fitzpatrick JM (2014) Minimally invasive image-guided cochlear implantation surgery: first report of clinical implementation the laryngoscope. Am Laryngol Rhinol Otol Soc 124:1915–1922Google Scholar
  11. 11.
    Vollmann B, Müller S, Kundrat D, Ortmaier T, Kahrs LA (2015) Methods for intraoperative, sterile pose-setting of patient-specific microstereotactic frames. In: Proceedings of SPIE, vol 9415, pp 94150M–94157Google Scholar
  12. 12.
    Rau TS, Lexow GJ, Blume D, Kluge M, Lenarz T, Majdani O (2017) Micro-stereotactic frame utilizing bone cement for individual fabrication: an initial investigation of its accuracy. In: Proc SPIE, vol 10135, p 10135–10139Google Scholar
  13. 13.
    Bell B, Williamson T, Gerber N, Gavaghan K, Wimmer W, Kompis M, Weber S, Caversaccio M (2014) An image-guided robot system for direct cochlear access. Cochlear Implants Int 15:11–13CrossRefGoogle Scholar
  14. 14.
    Majdani O, Rau TS, Baron S, Eilers H, Baier C, Heimann B, Ortmaier T, Bartling S, Lenarz T, Leinung M (2009) A robot-guided minimally invasive approach for cochlear implant surgery: preliminary results of a temporal bone study. Int J Comput Assist Radiol Surg 4:475–486CrossRefGoogle Scholar
  15. 15.
    Tauscher S, Fuchs A, Baier F, Kahrs LA, Ortmaier T (2017) High-accuracy drilling with an image guided light weight robot: autonomous versus intuitive feed control. Int J Comput Assist Radiol Surg 12:1763–1773CrossRefGoogle Scholar
  16. 16.
    Weber S, Gavaghan K, Wimmer W, Williamson T, Gerber N, Anso J, Bell B, Feldmann A, Rathgeb C, Matulic M, Stebinger M, Schneider D, Mantokoudis G, Scheidegger O, Wagner F, Kompis M, Caversaccio M (2017) Instrument flight to the inner ear. Sci Robot 2(eaal491):6Google Scholar
  17. 17.
    Zhu Y, Xu Y, Ke J, Ma F, Hu L, Li C (2014) Research on computer-assisted minimally invasive cochlear implant system. Appl Mech Mater 577:1241–1244CrossRefGoogle Scholar
  18. 18.
    Dahroug B, Tamadazte B, Tavernier L, Weber S, Andreff N (2018) Review on otological robotic systems: toward micro-robot assisted cholesteatoma surgery. In: IEEE reviews in biomedical engineering, early access, ahead of printGoogle Scholar
  19. 19.
    Ansó J, Wimmer W, Rathgeb C, Gerber N, Schneider D, Hermann J, Williamson T, Mantokoudis G, Caversaccio M, Weber S, Gavaghan K (2017) Robotic cochlear implantation—first clinical experiences. In: Proceedings of 16th annual meeting of the German society for computer and robot assisted surgery, CURAC 2017, pp 144–150Google Scholar
  20. 20.
    Camarillo DB, Krummel TM, Kenneth SJ (2004) Robotic technology in surgery: past, present, and future. Am J Surg 188:2–15CrossRefGoogle Scholar
  21. 21.
    Barbash GI, Glied SA (2010) New technology and health care costs—the case of robot-assisted surgery. N Engl J Med 363:701–704CrossRefGoogle Scholar
  22. 22.
    Dillon NP, Balachandran R, Fitzpatrick JM, Siebold MA, Labadie RF, Wanna GB, Withrow TJ, Webster RJ (2015) A compact bone-attached robot for mastoidectomy. J Med Device 9:31–37CrossRefGoogle Scholar
  23. 23.
    Cho B, Matsumoto N, Mori M, Komune S, Hashizume M (2014) Image-guided placement of the Bonebridge without surgical navigation equipment. Int J Comput Assist Radiol Surg 9:845–855CrossRefGoogle Scholar
  24. 24.
    Neumuth T (2016) Surgical process modeling. Innov Surg Sci 2:123–137Google Scholar
  25. 25.
    Lalys F, Jannin P (2014) Surgical process modeling: a review. Int J Comput Assist Radiol Surg 9:495–511CrossRefGoogle Scholar
  26. 26.
    MacKenzie L, Ibbotson JA, Cao CGL, Lomax AJ (2001) Hierarchical decomposition of laparoscopic surgery: a human factors approach to investigating the operating room environment. Minim Invasive Therapy Allied Technol 10:121–127CrossRefGoogle Scholar
  27. 27.
    Neumuth D, Loebe F, Herre H, Neumuth T (2011) Modeling surgical processes: a four-level translational approach. Artif Intell Med 51(3):147–161CrossRefGoogle Scholar
  28. 28.
    Neumuth T, Schumann S, Strauß G, Jannin P, Meixensberger J, Dietz A, Lemke HU, Burgert O (2006) Visualization options for surgical workflows. Int J Comput Assist Radiol Surg 1:438–440Google Scholar
  29. 29.
    Kobler JP, Prielozny L, Lexow GJ, Rau TS, Majdani O, Ortmaier T (2015) Mechanical characterization of bone anchors used with a bone-attached, parallel robot for skull surgery. Med Eng Phys 37:460–468CrossRefGoogle Scholar
  30. 30.
    Kobler JP, Wall S, Lexow GJ, Lang CP, Majdani O, Kahrs LA, Ortmaier T (2015) An experimental evaluation of loads occurring during guided drilling for cochlear implantation. Int J Comput Assist Radiol Surg 10:1625–1637CrossRefGoogle Scholar
  31. 31.
    Schneider V, Mueller S, Nuelle K, Kahrs LA, Majdani O, Ortmaier T (2017) Experimental accuracy optimization of a parallel kinematic tool for minimally invasive cochlear-implant surgery. In: Proceedings of 16th annual meeting of the German society for computer and robot assisted surgery, CURAC 2017, pp 202–207Google Scholar
  32. 32.
    Kobler JP, Beckmann Dl, Rau TS, Majdani O, Ortmaier T (2014) An automated insertion tool for cochlear implants with integrated force sensing capability. Int J Comput Assist Radiol Surg 9:481–494CrossRefGoogle Scholar

Copyright information

© CARS 2019

Authors and Affiliations

  • Samuel Müller
    • 1
    Email author
  • Lüder A. Kahrs
    • 1
  • Johannes Gaa
    • 1
  • Sebastian Tauscher
    • 1
  • Marcel Kluge
    • 2
  • Samuel John
    • 2
  • Thomas S. Rau
    • 2
  • Thomas Lenarz
    • 2
  • Tobias Ortmaier
    • 1
  • Omid Majdani
    • 2
  1. 1.Leibniz Universität Hannover Institute of Mechatronic SystemsHannoverGermany
  2. 2.Department of OtorhinolaryngologyHannover Medical SchoolHannoverGermany

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