Introduction
A secondary sternal fixation or reconstruction of a medial sternotomy
can be indicated after median sternotomy infection or bony non-union.
Although rare, they go accompanied with significant morbidity(1). In our
centre we routinely use Synthes® Titanium Sternal Fixation System for a
secondary sternal reconstruction after bony non-union or after healing
of median sternotomy infection. The procedure offers good results (1),
but can be, especially in the case of a complex non-union, or a complex
anatomy, time-consuming. To perform a good reconstruction the titanium
plates need to be bent to the anatomical shape of the sternum and
adjacent ribs, to ensure stable refixation, this part of the
perioperative procedure is very time-consuming. Working with Materialise
(Leuven, Belgium), we developed a technique using 3-dimensional planning
and patient specific surgical 3D-printed guide to simplify and quicken
the procedure.
Using preoperative 3-dimensional planning and patient-specific surgical
guides to aid in surgical procedures isn’t something new, it has been in
use since a few years, mostly used in orthopedic procedures (2,3).
We describe how we perform a secondary sternal refixation after
non-union of a medial sternotomy using a preprinted 3D model of the
patient’s sternum to achieve reduction in operating time. We were able
to reduce operating time by almost fifty percent. We could bend the
titanium fixation plates in almost perfect anatomical shape before the
procedure itself took place.
We describe two patients where we were able to use this technique.
Three-dimensional planning based on computed tomography images of the
mal-united and non-united sternum enabled us to produce a
patient-specific 3D printed sternum, and enabled us to custom pre-bend
the titanium plates. This article will describe how we do it.
METHODS:
Two patients were included with indication for sternal refixation or
reconstruction following sternal dehiscence after cardiac surgery.
All patients undergo a high-density computed tomography (CT) of the
chest to achieve optimal image quality.
Then, pre-operatively, the procedure was simulated through software
(Materialise, Belgium), including emulated reduction of both sternal
halves into anatomical position. The resulting 3-dimensional image was
then used to print the patient specific anatomical model.
On this real-life representable sternal model the titanium sternal
plates were bent, in anatomical position, removing the necessity for
bending them perioperatively.
The actual perioperative procedure remained unchanged. Reuse of the old
incision, removing of the old stainless steel wires, if in situ,
debridement of the sternal edges, obtainment of hemostasis. Mobilizing
of the pectoralis major muscles to expose the ribs, and reduction of the
sternal halves.
After reduction the plates are fitted in place and fixated on the
sternum, rarely additional bending is necessary, and if needed, the
additional bend is minimal.
RESULTS:
Case 1: Total bending time for a relative simple anatomic shape and
mal-union was 53 minutes (figure 1, figure 2). Total operative time was
1 hour 19 minutes.
Case 2: Total bending time for a complex non-union and anatomy was 1
hour 21 minutes (figure 3, figure 4). Total operative time was 1 hour 43
minutes.
One year follow-up yielded good clinical and cosmetic results.
DISCUSSION:
Both cases have shown a reduction in operative time, in our centre, as
in previous experience without the pre-bent titanium plates, more than
double the amount of time would have been spent in the described cases.
Attention to the exact same reduction as performed during the emulation
of the procedure is critical to achieve good reduction of the sternal
halves, without the exact same reduction, there could be more time
needed to adjust the titanium plates, eliminating some advantage of
using the preprinted model.
A possible reduction in length of stay or reduced use of analgesia when
using the preoperative 3-dimensional planning and patient-specific
surgical guide is out of scope of this pilot project and is subject to
more research.
CONCLUSIONS:
This pilot study demonstrates that 3-dimensional planned
patient-specific guides and preoperative preparations can help reduce
operating time with satisfactory preliminary results.
Declarations:
Ethics approval and consent to participate: Consent acquired, Ethical
committee not applicable.
Consent for publication: Consented
Availability of data and material: Available
Competing interests: none to declare
Funding: Research Grant Sint Antonius Hospital Nieuwegein
Authors’ contributions:
Haenen F., M.D.: author, design
Vos R.J., M.D.: co-author, pre-operative support
Daeter E.J., M.D.: supervisor, surgeon, design
Acknowledgements: Materialise, Leuven, Belgium
Reference:
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Figures
Figure legend:
Figure 1: a: frontal view of a non-complex sternal mal-union, with
pre-bent titanium fixation plates. b: sideview of the patient specific
3D model with appreciation of the anatomical shaping of the Synthes®
titanium fixation plates.
Figure 2: a: pre-operative 3-dimensional model of a complex sternal
anatomy with non-union. b: peroperative result after relatively easy
implantation of the fixation plates.