An individually mouldable surgical targeting system

Minimally-invasive cochlear implantation surgery requires appropiate surgical tools to drill a single bore hole from outside the skull directly down to the basal turn of the cochea. In this project a new concept for providing a customized surgical tool, also known as “micro-stereotactic frame” had been developed. Main idea is to utilize bone cement to fix the individual pose of the template according to a previosly planned trajectory using individual images (e.g. CT or CBCT). This new surgical targeting system includes an aligment device, referred to as “Jig Maker”, based on a passive hexapod with manually adjustable legs for temporary fixation of the single components (disposables) until the bone cement is cured. In a preliminary study, 18 samples of the surgical template were fabricated and evaluated regarding their positioning accuracy. The mean positioning error at the target point (located in a depth of approx. 70 mm) was 0.30 mm with a standard deviation of 0.25mm.

The developed system allows the patient specific individualization of a drill guide under sterile conditions. It does not require expensive equipment or technical personal. The whole process can be performed by OR staff in few minutes. These are advantages compared to previously developed systems and might facilitate its integration into clinical routine.

Pictures showing an early prototype of the GluingJig


If your are interested in this technology, want to join a collaboration for further development, or just have additional questions please do not hesitate to contact:

Dr.-Ing. Thomas Rau


This work was supported by the start-up grant for young researches ‘HiLF‘ of Hannover Medical School.


  • European patent granted in 2017 and validated in DE, FR, GB, CH, NL: Rau Th. S., Majdani O., Lenarz T., Kahrs L. A.: Surgical guidance device and method for its preparation. EP 3 058 890 B1. [ Patent].
  • US patent application is pending. US 2018/0008367 A1 [ PAP].

Further Reading:

Rau Th., Uhlenbusch L., Witte S., Lexow J., Kahrs LA, Lenarz Th., Ortmaier T., Majdani O. (2018b): Determination of error sources and values for an individually mouldable surgical targeting system. In Proc. 32nd International Congress and Exhibition on Computer Assisted Radiology and Surgery (CARS), June 20-23, Berlin, Germany. [ doi].
Rau Th. S., Lexow G. J., Blume D., Kluge M., Lenarz Th., Majdani O. (2017): Micro-stereotactic frame utilizing bone cement for individual fabrication. An initial investigation of its accuracy. In Proc. SPIE Medical Imaging 2017: Image-Guided Procedures, Robotic Interventions, and Modeling, 101350P. [ doi].
Rau Th. S., Lexow G. J., Kluge M., Lenarz Th., Majdani O. (2016): An alternative concept for template-guided minimally-invasive cochlear implantation surgery. In: Ansó J. et. al (Hrsg.): Proc. 15th Annual Meeting German Society for Computer- and Robot-Assisted Surgery (CURAC), 29.09.-01.10.2016, Bern. Seiten 149-154. [ doi].
Uhlenbusch L. (2017): Investigation of accuracy and error sources of a surgical template made of bone cement. Unpublished Bachelor Thesis. Department of Otolaryngology at MHH and Institute of Mechatronic Systems at LUH.
Witte S. (2018): Experimental evaluation of the mouldable surgical targeting system ‘GluingJig’ using skull phantoms. Doctoral Thesis under progress.

About The VIANNA research team