This study evaluated the use of computer-assisted surgery using 3D planning and surgical guides compared to conventional surgery for reconstructing jaw defects with free vascularized fibular flaps. The computer-assisted approach significantly reduced shaping time and ischemic time compared to conventional surgery. It also eliminated discrepancies between the size of the fibula defect and transplant size. One flap failed in the conventional group, while all flaps were successful with the computer-assisted approach. The results suggest computer-assisted surgery may improve outcomes for fibular flap reconstruction of jaw defects.

1. Evaluation of computer-assisted jaw reconstruction
with free vascularized fibular flap compared to
conventional surgery: a clinical pilot study
Ali Modabber*†
Christina Legros†
Majeed Rana
Marcus Gerressen
Dieter Riediger
Alireza Ghassemi
Department of Oral, Maxillofacial and
Plastic Facial Surgery, University
Hospital Aachen, Germany
*Correspondence to: A. Modabber,
Department of Oral, Maxillofacial
and Plastic Facial Surgery, University
Hospital Aachen, Pauwelsstrasse 30,
52074 Aachen, Germany.
E-mail: amodabber@ukaachen.de
†
These authors contributed equally
to this study.
Abstract
Background The introduction of computer-assisted surgery was a milestone
in functional reconstructions of facial skeletal defects.
Patients and methods We compared five computer-assisted and five conven-
tional reconstructions with fibular grafts in the course of a pilot study. A rapid
prototyping guide translated the computer-assisted surgery plan into intra-
operative utilizable models. We intraoperatively measured the time needed
for shaping the graft to the recipient site and the ischaemic time. Furthermore,
the size of donor site defect compared to the required transplant length was
evaluated.
Results Shaping procedure and ischaemic time turned out significantly
shorter when compared to conventional surgery without cutting guide
(p = 0.014). Using surgical guides, there was no change between the defect
size of the fibula and the necessary transplant size. In conventional surgery,
a mean change of 1.92 cm occurred (p = 0.001).
Conclusion The surgical guide significantly reduced shaping time and
consequently ischaemic time. These factors can influence flap survival. The
fibular donor site defect was downsized. Copyright © 2011 John Wiley &
Sons, Ltd.
Keywords three-dimensional virtual planning; free fibular flap; reconstruction of
the jaw; computer-assisted surgery
Introduction
Maxillary and mandibular continuity defects frequently occur after oral cancer,
benign mandibular tumours, severe osteomyelitis, accidents and gunshot
wounds. The location and dimensions of the defect provide essential informa-
tion for the surgical treatment. The functional and aesthetic outcome of such
reconstructions is influenced by the position and shape of the graft. In fact,
the goal is to achieve the best possible functional outcome in the form of the
restoration of mastication (1), swallowing and phonation as well as an at least
satisfying facial appearance. The chances of success depend on the surgeon’s
competence, the patient’s condition and accurate preoperative planning (1).
Microvascularized free fibular flaps represent a state-of-the-art reconstruction
method after mandibular removal, especially for long bone defects combined
with overlying soft tissue replacement (2–4). Fibular flaps are also often
applied in maxillary reconstructions (5–7) because of the comparatively long
ORIGINAL ARTICLE
Received: 8 November 2011
Copyright © 2011 John Wiley & Sons, Ltd.
THE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY
Int J Med Robotics Comput Assist Surg (2011)
Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/rcs.456

2. pedicle. In general, the fibula offers several advantages,
such as providing an adequate bone length, which may
reach up to 25 cm (4). In addition, fibular grafts have
lower bone resorption rates in comparison to avascular
grafts (8). The calibre of the peroneal vessels is suitable
for microanastomosis with cervical vessels (9,10). As
described in the literature, septocutaneous and musculo-
cutaneous branches can adequately supply a skin paddle
22–24 cm long and 10–14 cm wide (10), which provides
a large area of skin for intra- and extraoral or combined
replacement.
A limitation of the fibular graft is its smaller diameter,
which is rarely more than 15 mm (11). Its height may
cause a vertical deviation between the jaws, so that the
conditions for prosthetic rehabilitation with implant-
supported prostheses are restrained. The problem can be
solved by the ‘double-barrel’ graft or via vertical distrac-
tion osteogenesis (11,12). The surgical approach to the
fibula is either lateral, as described by Gilbert (13), or it
can be elevated from posterior, as reported by Taylor
(9). The failure rate in these flaps is variable but in
general low, ranging between 25% when combined with
a skin paddle and 11.7% for pure bone grafts (14). The
donor site morbidity after removal of the fibula is
described as low (15).
Three-dimensional (3D) modelling assisted by com-
puted tomography has been an ideal method of obtaining
information for reconstructive surgery, especially to proj-
ect explantation of the graft with subsequent transplanta-
tion into the defect. Transformation of the digital CT data
to the 3D software simulation of the operative field and
the donor region provides a detailed and precise analysis
from all aspects. It serves as a diagnostic tool to plan the
size, shape and exact placement of the bone graft (16),
which may be of significant clinical benefit. Thus, com-
puter-assisted surgery may help to simplify the shaping
of the bone graft and to enhance precision in order to
achieve an optimal aesthetic outcome, as well as a reduc-
tion in operating time (17). Paleologos et al. also report a
‘positive effect on the complication rate and thus on inten-
sive care unit and hospital stays, with attendant financial
implications’ (18). Computer-assisted planning provides
accuracy in detail without loss of information, and a num-
ber of alternative surgical procedures can be created (17).
A stereolithographic model for transferring the preopera-
tive planning can demonstrate only one scenario. To per-
form various scenarios, surgical planning software can
be convenient and cost-effective (19). In order to bring
the perfected surgical simulation plan to real-time sur-
gery, operation templates fabricated by a selective laser
sintering technique, providing accurate modelling of de-
tailed anatomical structures of the defect, are very helpful
to exactly translate the surgical procedure. Various
approaches demonstrate the benefit of prefabricated 3D
image templates linking the operation plan to the surgical
procedure (20–23). The aim of this pilot study was to
determine whether this established computer-assisted
method has an influence on the duration of the surgery
and the amount of bone removed, and thus whether it
should be routinely used in all patients undergoing fibular
reconstruction of maxillary or mandibular defects.
Materials and methods
After institutional approval and written informed consent,
10 patients (two female and eight male) were randomly
divided into two groups, using block randomization. All
patients received secondary maxillary or mandibular
reconstruction with free vascularized fibular flaps. Among
these flaps, four were combined osteocutaneous trans-
plants also containing a skin paddle, three for mandibular
and one for maxillary reconstruction. Five patients
obtained conventional surgical treatment, whereas the
remaining five patients underwent computer-assisted sur-
gical planning in combination with an operation-sawing
template (Table 1).
During surgery, the time of shaping of transplants and
the ischaemic time were measured. In addition, the
change in size between the defect after removal of the
fibula shaft and the finally required transplant length
was evaluated.
For statistical analysis, we used the t-test for unrelated
samples, with a significance level of p = 0.05. Statistical
computations were performed using SPSS 14 (SPSS,
Chicago, IL, USA) under Windows 7.
Surgical planning and rapid prototyping
The translation from virtual plan to operating site was
carried out in five patients. We applied the commercially
available software SurgiCase CMF (Materialise NV,
Leuven, Belgium), whose implementation and establish-
ment were described previously (20–24).
A surgical guide linked the computer-assisted surgical
plan to the real-time operation, which was the required
step for implementable benefit. Preoperative CB-CT or
CT data in DICOM file format were imported into the
SurgiCase CMF software, which generated a 2D volume-
rendered image of the data. The process of segmentation
followed, in which artifacts were removed and all bony
structures of interest were isolated. A high-quality 3D
visualization was calculated from the reassessed image of
the defect for interactive evaluation. Size and neighbouring
structures could be guaged. Additionally, CT data of a
standard fibula donor site were applied to the software
and virtually adapted to the defect. With the help of
different surgical tools (segmentation, osteotomy modus,
mirroring tool, reconstruction wizard) the reconstruction
plan could be developed (Figure 1). According to the
surgeon, the best possible curvature and graft position were
discussed in different scenarios with regard to occlusion,
jawbone distance, condylar position, possible dental reha-
bilitation and aesthetic outcome. The SurgiCase project
was fine-tuned and the STL-format file was imported into
3Matic-software, in which the cutting guide was designed.
Via a rapid prototyping selective laser sintering method,
A. Modabber et al.
Copyright © 2011 John Wiley & Sons, Ltd. Int J Med Robotics Comput Assist Surg (2011)
DOI: 10.1002/rcs

3. the surgical template was manufactured out of polyamide
powder, solidified by a carboxide laser. The cutting guide
included all necessary information of the optimal agreed
virtual plan: the proximal and distal resection sites,
number, position and angulation of possible osteotomies
(Figure 2). Additionally a skull model of the defect was
built out of acrylic resin via rapid prototyping, visualizing
the defect area. It functioned as an intraoperative back-up
for the graft shaping before disconnecting the recipient
vessels. After steam sterilization, both tools were ready
for surgery.
Surgical procedure
The reconstruction with the free fibular flap, with or with-
out a skin paddle, was elevated in a two-team approach:
one surgical team prepared the defect region, while the
other elevated the graft. The transplant was exposed via
a lateral approach, according to Gilbert (13). The surgical
team was always the same. With previous computer-
assisted planning, the surgeon had a cutting template
and a defect model at his disposal. These tools were
applied at the moment the fibula was prepared but not
Figure 1. (A–C) 3D reconstruction suggestion for left-side mandible: autogenous fibular flap bent into the defect
Table 1. Patient characteristics, diagnosis, defect size, location, surgical treatment, number of osteotomies and flap design
Case
No. Age/gender Diagnosis
Defect size
(mm) Location
Surgical
treatment
Number of
osteotomies Flap design
1 54/m Midfacial projectile 48.0 Computer-assisted 2
Osteomyocutaneous
flap
2 54/f Chondrosarcoma 38.7 Computer-assisted 2
Microvascular bone
graft
3 50/m Ameloblastoma 63.9 Computer-assisted 3
Microvascular bone
graft
4 53/m Midfacial projectile 110.5 Computer-assisted 3
Osteomyocutaneous
flap
5 42/m
Squamous cell
carcinoma
89.7 Computer-assisted 2
Microvascular bone
graft
6 44/m Rhabdomyosarcoma 60.5
Conventional
treatment
2
Microvascular bone
graft
7 37/m Midfacial projectile 71.6
Conventional
treatment
2
Microvascular bone
graft
8 74/m
Squamous cell
carcinoma
68.8
Conventional
treatment
2
Osteomyocutaneous
flap
9 61/m Keratocyst 71.1
Conventional
treatment
3
Microvascular bone
graft
10 55/f
Squamous cell
carcinoma
46.8
Conventional
treatment
3
Osteomyocutaneous
flap
Evaluation of fibular jaw reconstruction
Copyright © 2011 John Wiley & Sons, Ltd. Int J Med Robotics Comput Assist Surg (2011)
DOI: 10.1002/rcs

4. yet osteotomized and still vascularized. The cutting guide
was attached to the fibula with due regard to its blood sup-
ply, and the graft was cut proximally and distally to the tem-
plate (Figure 3A, B). When supplementary osteotomy was
planned, a wedge, which was predetermined by the guide,
was lifted. After transection of the pedicle, the insertion into
the defect site followed immediately. Performing according
to the conventional method, the surgeon osteotomized the
fibula in the appropriate length according to the defect size
measured by the second team, and then the vessels were
transected. After positioning the flap into the defect in the
proper way and performing osteosynthesis with mini-plates,
anastomosis was conducted with the prepared recipient
vessels, followed by defect closure.
Results
The patients’ mean age was 52.4 (range 37–74) years. The
average defect size amounted to 66.96 (range 38.7–
110.5) mm.
Our data showed statistically significant differences with
regard to the shaping procedure and the ischaemic time.
Figure 4 shows our data, gauging different time periods
during the surgical treatment. The shaping procedure
specified the duration from the dissection of the pedicle
until finishing of the shaping procedure (p = 0.014). The
ischaemic time incorporates the dissection of the blood sup-
ply, the process of shaping into the defect area and the osteo-
synthesis of the flap, until the microsurgical anastomoses of
both the artery and the vein were released (p = 0.014).
When using the 3D image template, there was in no
case deviation between the size of the fibula defect and
the size of the transplant in the reconstruction site. In
conventional surgery we observed a mean deviation of
1.92 cm (p = 0.001) (Figure 5). Table 2 demonstrates all
significant statistical data.
In the conventional surgery group one flap failed, due
to venous thrombosis; the remaining nine flaps showed
no complications. Thus, the graft success rate was 80%
in conventional surgery and 100% in computer-assisted
surgical procedures.
Figure 2. 3D rapid prototyping cutting guide generated from the optimal agreed virtual transplant data: proposition of the graft
position
Figure 3. Real surgery course: (A) cutting template placed on the fibula while osteotomies are accomplished; (B) resection template
sited on the osteotomized pedicled flap for further wedge excision
A. Modabber et al.
Copyright © 2011 John Wiley & Sons, Ltd. Int J Med Robotics Comput Assist Surg (2011)
DOI: 10.1002/rcs

5. Discussion
For bony reconstruction of the facial skeleton, commonly
the fibula, iliac crest or scapula are the preferred donor
sites. Among these flaps, the fibula provides a sufficient
length of bone with mostly implantable bone dimension
to insert dental implants. The long pedicle with up to
12 cm allows more range of movement. It can be harvested
simultaneously by two teams. The low donor site morbidity
is favourable. Free vascularized fibular flaps have proved
their value in maxillary and mandibular reconstruction
(2–7). The growing body of evidence makes the fibula
the flap of choice in many of our reconstruction surgeries,
especially if soft tissue is needed.
The complex interplay of function and aesthetics
makes surgical reconstruction a great challenge. Therefore,
preoperative planning is necessary to evaluate the defect
size and the relation to neighbouring structures and to
choose the best possible reconstruction plan. Standard
radiographic views, plain tomography, computed tomogra-
phy and magnetic resonance imaging produce a two-
dimensional (2D) image of the patient. CT and MRI data
include the information for 3D images, as their pictures
consist of multiple body-imaging slices, but without further
processing of the data they only provide 2D images. The
possibility of analysing the patient with regard to the entire
facial skeleton in 3D is more precise, makes an overall
evaluation possible and supplies valuable information,
which greatly facilitates further treatment. Accurate appre-
ciation of the bone defect and its surrounding structures
can be measured. The virtual surgery plan requires a pre-
cise 3D model, conforming to the standards of the defect,
as the basis for the design of the transplant in shape, posi-
tion and angulation. Different surgical tools are asked from
the software to perfect the surgery plan.
First steps to link the operation plan with real-time
surgery were performed by using defect models produced
via CAD/CAM, milling or laser technology, acquired from
CT or MR images without virtual assistance. On these
solid models, reconstruction plates were pre-bent as
surgery templates.
The computer-assisted method used, SurgiCase CMF
(Materialise NV), described by Leiggener et al. (24) as
the first, is a commercially available service for preopera-
tive planning. It delivers a template for intraoperative
use based on a perfected virtual operation plan, which
is made with the aid of simulation before surgery. The
goal was to evaluate the benefit of this method for
transplantation in comparison to the conventional
treatment in a pilot study with a limited number of
patients.
Figure 4. Data allocation of time measurements during the
surgical treatment, opposing conventional and computer-assisted
surgery
Figure 5. The analysis opposes the donor region to the recon-
struction site, pointing the discrepancy between explant size
and required size
Table 2. Statistical data
n Mean SD p 95% CI
Lower Upper
Shaping procedure
Computer-assisted surgery 5 18 6.82 0.014 À36,78 À56.21
Conventional surgery 5 39.2 13.48
Ischaemic time
Computer-assisted surgery 5 104.8 13.95 0.014 À45.95 À6.85
Conventional surgery 5 131.2 12.83
Osteotomy size
Donor site 5 6.67 0.61 0.001 À2.76 À1.07
Defect region 5 8.58 0.55
Evaluation of fibular jaw reconstruction
Copyright © 2011 John Wiley & Sons, Ltd. Int J Med Robotics Comput Assist Surg (2011)
DOI: 10.1002/rcs

6. During our surgical procedure the exact transplant
shape and size, its number and site of osteotomies to be
performed, have already been determined. Immediate
insertion followed the explantation, as no time for shaping
was necessary. Due to the faster fitting process, the average
ischaemic time was decreased. Increased ischaemic time of
a bone graft and its soft tissue is a risk factor.
Picard-Ami et al. (25) describe a significant influence
between ischaemic time and the survival rate of grafts. Con-
sequently the ischaemic time period between graft delivery
and revascularization must be kept to a minimum. The
findings of our evaluation are significant shorter ischaemic
times when using the surgery template (p = 0.014), as a
result of the quicker shaping procedure (p = 0.014).
Furthermore, when using the template no fibula length
was immolated, as the transplant fitted well into the defect.
The fibula and the interosseous membrane are sites for
muscle attachments that allow muscle torque. With growing
defect size the muscle strength may be impaired. ‘An inverse
relationship existed between the length of the resected
fibula and the muscle strength of the ankle evertors’ (26).
In addition, interruption of the tibiofibular unit discontinues
the load transfer through the ankle joint, which is depen-
dent on the integrity of the interosseous membrane (27).
Lee et al. (27) demonstrated that ‘longer segments site are
less osteoporotic, because there is more available interos-
seous membrane to connect and stabilize the fibula to the
tibia.’ Effectiveness and precision were improved by signifi-
cantly minimizing the fibular defect (p = 0.001).
With the help of rapid prototyped cutting guides, trans-
plantation can be carried out faster, precision and control
may be scaled up, the shaping process of the transplant
and the ischaemic time are shortened and the donor site
defect is minimized. The increased efficiency ensures out-
comes of constant high quality in function and aesthetics.
Growing complexity in extensive mandible defects may
raise this method’s indication, as the surgery might be
well simplified for such defect location, and unavoidable
osteotomies no longer influence the lead time. In our
opinion, the decreased ischaemic time and the predictabil-
ity of the surgical outcome outweigh the total cost of about
€1000 for the presented surgical guide.
We are aware that larger sample sizes will be required
to evaluate further benefits of computer-assisted recon-
structions of facial skeleton with vascularized flaps.
Acknowledgement
The authors thank Maarten Zandbergen (Materialise NV,
Leuven, Belgium) for his valuable support.
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DOI: 10.1002/rcs