IDEAS AND TECHNICAL INNOVATIONS Surgical planning, manufacturing and implantation of an individualized cervical fusion titanium cage using patient-specific data Uwe Spetzger 1 • Miles Frasca 2 • Stefan Alexander Ko ¨nig 1 Received: 31 July 2015 / Revised: 18 February 2016 / Accepted: 19 February 2016 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract Background Most cervical fusion cages imperfectly mimic the anatomy of the intervertebral disc space. The production of individualized cages might be the next step to further improve spinal implants due to their enhanced load-bearing surface. Objective To evaluate the planning, manufacturing, and implantation of an individualized cervical cage in co-op- eration with EIT and 3D Systems. Methods A digital 3D model of the patient’s cervical spine was rendered from the patients CT data. It was then possible to correct degenerative deformities by digitally repositioning the vertebrae and virtually resecting the osteophytes. The implantation of the cage can be simulated to check the accuracy of the fit. The cage is made of tra- becular titanium and manufactured by Direct Metal Printing. Results The pilot project for the implantation of the first individualized cervical cage ever, resulted in a highly accurate fit. During surgery, the cage self-located into the correct position after suspending distraction due to the implants unique end plate design. Furthermore, it was impossible to move the cage in any direction with the inserting instrument after suspending distraction for the same reason. Thus, it can be assumed that an individualized cervical implant provides excellent primary stability. Conclusion Preconditions for the manufacturing of indi- vidualized cervical fusion cages using specific patient data are given. The implantation is uncomplicated. The improved load-bearing surface will lower the rate of implant dislocation and subsidence. The production of individualized cages at a reasonable price has to be eval- uated by spine surgeons and the industry. Keywords Titanium cage Á Cervical spine Á Fusion Á Patient data Á Computer-aided design Á 3D modeling Á Manufacturing Introduction The implantation of intervertebral fusion cages made of polyether-etherketone or titanium with or without anterior plating has been the standard surgical therapy for the treatment of spondylotic cervical myelopathy and/or radiculopathy for many years [1–4]. The numerous cervical cages offered by the industry mimic the anatomy of the intervertebral disc space more or less whereat size and design of the cages are adapted to average shapes and sizes of intervertebral discs. For the reconstruction of several bony defects in the human body such as skull defects individualized implants based on the patient’s CT data have been used on a routine base for many years [5–8]. Thus, it was a logical step to evaluate the technical possibilities for the manufacturing of individualized fusion implants for the cervical spine toge- ther with our industrial partners EIT (Emerging Implant Technologies GmbH, Tuttlingen, Germany) and 3D Sys- tems (Rock Hill, SC, USA). Electronic supplementary material The online version of this article (doi:10.1007/s00586-016-4473-9) contains supplementary material, which is available to authorized users. & Stefan Alexander Ko ¨nig [email protected]1 Neurochirurgische Klinik, Klinikum Karlsruhe, Moltkestr. 90, 76133 Karlsruhe, Germany 2 3D Systems Corporation, Rock Hill, SC, USA 123 Eur Spine J DOI 10.1007/s00586-016-4473-9
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IDEAS AND TECHNICAL INNOVATIONS
Surgical planning, manufacturing and implantationof an individualized cervical fusion titanium cageusing patient-specific data
Uwe Spetzger1 • Miles Frasca2 • Stefan Alexander Konig1
Received: 31 July 2015 / Revised: 18 February 2016 / Accepted: 19 February 2016
� Springer-Verlag Berlin Heidelberg 2016
Abstract
Background Most cervical fusion cages imperfectly
mimic the anatomy of the intervertebral disc space. The
production of individualized cages might be the next step
to further improve spinal implants due to their enhanced
load-bearing surface.
Objective To evaluate the planning, manufacturing, and
implantation of an individualized cervical cage in co-op-
eration with EIT and 3D Systems.
Methods A digital 3D model of the patient’s cervical
spine was rendered from the patients CT data. It was then
possible to correct degenerative deformities by digitally
repositioning the vertebrae and virtually resecting the
osteophytes. The implantation of the cage can be simulated
to check the accuracy of the fit. The cage is made of tra-
becular titanium and manufactured by Direct Metal
Printing.
Results The pilot project for the implantation of the first
individualized cervical cage ever, resulted in a highly
accurate fit. During surgery, the cage self-located into the
correct position after suspending distraction due to the
implants unique end plate design. Furthermore, it was
impossible to move the cage in any direction with the
inserting instrument after suspending distraction for the
same reason. Thus, it can be assumed that an individualized
Conclusion Preconditions for the manufacturing of indi-
vidualized cervical fusion cages using specific patient data
are given. The implantation is uncomplicated. The
improved load-bearing surface will lower the rate of
implant dislocation and subsidence. The production of
individualized cages at a reasonable price has to be eval-
uated by spine surgeons and the industry.
Keywords Titanium cage � Cervical spine � Fusion �Patient data � Computer-aided design � 3D modeling �Manufacturing
Introduction
The implantation of intervertebral fusion cages made of
polyether-etherketone or titanium with or without anterior
plating has been the standard surgical therapy for the
treatment of spondylotic cervical myelopathy and/or
radiculopathy for many years [1–4].
The numerous cervical cages offered by the industry
mimic the anatomy of the intervertebral disc space more or
less whereat size and design of the cages are adapted to
average shapes and sizes of intervertebral discs.
For the reconstruction of several bony defects in the
human body such as skull defects individualized implants
based on the patient’s CT data have been used on a routine
base for many years [5–8]. Thus, it was a logical step to
evaluate the technical possibilities for the manufacturing of
individualized fusion implants for the cervical spine toge-
ther with our industrial partners EIT (Emerging Implant
Technologies GmbH, Tuttlingen, Germany) and 3D Sys-
tems (Rock Hill, SC, USA).
Electronic supplementary material The online version of thisarticle (doi:10.1007/s00586-016-4473-9) contains supplementarymaterial, which is available to authorized users.