1) The document describes a study comparing computer-assisted mandibular reconstruction using vascularized iliac crest bone grafts to conventional reconstruction techniques. 2) With computer-assisted planning, a surgical guide was designed based on CT scans and used to precisely shape and position the bone graft. This method aimed to reduce operating time and bone removal compared to conventional techniques. 3) Results found that with computer-assisted planning, the bone graft fit perfectly into the mandibular defect with less adjustment needed. Operating time and bone removed were also reduced compared to conventional techniques. Patients reported higher satisfaction with their appearance.

1. INNOVATIVE TECHNIQUES
Computer-assisted Mandibular Reconstruction with Vascularized
Iliac Crest Bone Graft
Ali Modabber • Marcus Gerressen • Maria Barbara Stiller •
Nelson Noroozi • Alexander Fu¨glein • Frank Ho¨lzle •
Dieter Riediger • Alireza Ghassemi
Received: 16 September 2011 / Accepted: 2 February 2012
Ó Springer Science+Business Media, LLC and International Society of Aesthetic Plastic Surgery 2012
Abstract
Background The intention of mandibular reconstructive
surgery is to achieve maximum possible functionality,
which means the restoration of masticatory function and
speech with a good esthetic result.
Methods We compared five computer-assisted mandibu-
lar reconstructions with 15 conventional mandibular
reconstructions performed using vascularized iliac crest
bone grafts. Based on preoperative cone beam computed
tomography (CBCT) or CT data imported into the specific
surgical planning software, a surgical guide was designed
by rapid prototyping that helped to exactly translate the
virtual surgery plan into the operation site whereby it fit
uniquely to the iliac donor site. The ischemic time of the
graft was measured intraoperatively and the difference
between the amount of bone removed and the amount of
bone required was determined. In addition, 3 months after
surgery patients had to score the esthetics of their outer
appearance using a visual analog scale.
Results In all patients the graft fit perfectly into the
mandibular defect without major adjustments. The time for
the shaping process of the transplant and the ischemic time
were shorter than in the conventional grafting procedure.
The virtual plan reduced the amount of bone removed to
the required volume. The patients who underwent com-
puter-assisted reconstruction had a higher degree of satis-
faction with their outer appearance.
Conclusion Our clinical experience and the collected data
suggest that the described method is very promising for
optimizing the surgical result of mandibular reconstruc-
tions using iliac crest bone grafts and achieving an excel-
lent esthetic outcome.
Level of Evidence IV This journal requires that authors
assign a level of evidence to each article. For a full
description of these Evidence-Based Medicine ratings,
please refer to the Table of Contents or the online
Instructions to Authors www.springer.com/00266.
Keywords Computer-assisted surgery Á Mandibular
reconstruction Á Vascularized iliac crest bone graft Á
Surgical guide Á Virtual planning
Vascularized bone grafts play an important role in the
reconstruction of large facial bony defects, especially of
the mandible, as they offer the potential for good functional
and esthetic outcomes [1–3]. Microsurgically revascular-
ized iliac crest bone grafts have the benefit of a rich can-
cellous blood supply, a large amount of bone, and a
compact cortex providing an ideal site for plate fixation and
insertion of dental implants [4].
Accurate and careful preoperative planning can increase
the predictability of the result and the success rate of
vascularized bone grafts. Virtual three-dimensional (3D)
simulations are gaining recognition with regard to surgical
planning due to the almost unlimited possibilities of dif-
ferent treatment scenarios and their improving accuracy
[5]. In most cases stereolithographic models are used to
preoperatively provide an exact 3D replica of the mandible
and to contour the missing bony area of the jaw [6]. Other
methods draw on prebent plates for conducting mandibular
reconstruction [7].
A. Modabber Á M. Gerressen Á M. B. Stiller Á N. Noroozi Á
A. Fu¨glein Á F. Ho¨lzle Á D. Riediger Á A. Ghassemi
Department of Oral, Maxillofacial and Plastic Facial Surgery,
University Hospital Aachen, Aachen, Germany
A. Modabber (&)
Pauwelsstrasse 30, 52074 Aachen, Germany
e-mail: amodabber@ukaachen.de
123
Aesth Plast Surg
DOI 10.1007/s00266-012-9877-2

2. Fig. 1 a1/a2 Three-dimensional suggested reconstruction for the
anterior mandible with autogenous bone graft from the left iliac crest
osteotomized and bent into the defect. b1/b2 Three-dimensional
virtual reconstruction of the left lower jaw with autogenous bone graft
from the right iliac crest fitted perfectly into the defect
Aesth Plast Surg
123

3. Fig. 1 continued
Aesth Plast Surg
123

4. The aim of the current study was to evaluate whether
mandibular reconstructions with vascularized iliac bone
grafts from a surgical guide based on computer-assisted
planning are more favorable compared to the conventional
technique.
Patients and Methods
After obtaining institutional approval and written informed
consent, the translation from a virtual plan to the operating
site by a surgical guide was carried out in five patients (two
female and three male) with extensive mandibular defects.
Preoperative cone beam computed tomography
(CBCT) or CT data in DICOM file format were imported
into the software (SurgiCase CMF, Materialise N.V.,
Leuven, Belgium). The process of segmentation followed
in which artifacts were removed and all bony structures of
interest were isolated. A high-quality 3D visualization of
the mandible was calculated and if necessary the desired
resections were performed virtually by using different
surgical tools (segmentation, osteotomy modus, mirroring
tool, and reconstruction wizard). The shape of the man-
dible before resection or the mirror image of the healthy
side served as reference for the virtual reconstruction of
the affected mandibular area. In addition, angiographic
CT scans of the iliac donor site, which allowed for a 3D
reconstruction of the arteries, were applied to the soft-
ware. Depending on the vascularization, the position of
the afterward selected graft was determined at the iliac
crest.
After virtual reconstruction of the defect area, the best-
fitting area of the iliac crest was selected, with the position
of the vessels nourishing the iliac graft also taken into
account. The donor site was virtually osteotomized and
then placed into the mandibular defect (Fig. 1). According
to our surgical experience, the best possible curvature and
graft position were discussed in different scenarios with
regard to occlusion, condylar position, possible dental
rehabilitation, and esthetic outcome.
Fig. 3 a Three-dimensional design of the surgical guide, generated
from the optimally constructed virtual transplant data, positioned on
the right iliac crest. b The exactly sawed and osteotomized iliac crest
bone graft is still vascularized after resection of the ventral part of the
anterior superior iliac spine
Fig. 2 a The surgical guide is temporarily fixed on the external side of the left iliac ala by means of osteosynthesis screws, ready for sawing.
b The arrow points to the deep circumflex iliac artery at the medial side of the iliac crest
Aesth Plast Surg
123

5. After fine adjustment, the data were imported into the
3-Matic software as an STL file. Thus, based on the final
plan, a surgical guide that fit uniquely to the iliac crest and
indicated the desired osteotomy lines, graft size, and
angulation was designed. In primary mandibular recon-
struction, a resection guide was designed by which the
planned mandibular osteotomy could be transmitted in real-
time surgery. With the aid of the rapid prototyping selective
laser sintering method, the guide was manufactured out of
polyamide powder and solidified by a carboxide laser. In
addition, an anatomical skull model showing the defect area
was fabricated using a stereolithographic technique.
Subsequent to sterilization, the anatomical model and
the surgical guide were employed during surgery. After
preparation of the graft and its nutrient vessels, the tem-
plate was temporarily fixed at the bone of the iliac ala by
miniscrews (Fig. 2). The bone graft was sawed in the
desired shape (Fig. 3). The graft, still pedicled, was os-
teotomized and contoured using the surgical guide and with
the additional aid of the stereolithographic model. After
providing the graft with miniplates or reconstruction plates
in predetermined positions, the graft pedicle was transected
followed immediately by insertion into the defect site.
During surgery, the ischemic time of the graft was
measured. In addition, the difference between the amount
of bone removed and the amount of bone required was
determined. 3 months postoperatively all patients scored
their outer appearance on a visual analog scale of
0–100 mm. The acquired data from the five patients were
retrospectively compared with data from our database of
the last 2 years. In the database we were able to find
accurate information about 15 patients (four female and 11
male) who underwent conventional mandibular recon-
structions with a vascularized iliac crest bone graft.
Table 1 gives the characteristics of all patients.
The flap survival rate was assessed clinically and
radiologically with regard to a proper healing process and
in the end intraoperatively during plate removal 6 months
after reconstruction.
Results
The mean age of the patients who underwent computer-
assisted surgery was 57.2 years (range = 20–81 years) and
56.2 years (range = 31–80 years) for those who under-
went conventional reconstruction. The average defect size
was 76.16-mm (range = 63.9–90.5 mm) in the computer-
assisted reconstruction group and 73.23-mm (range =
60.5–96.8 mm) in the conventional surgery group.
The surgical guide allowed the implementation of prede-
termination of the graft with regard to its shape and size as
Table 1 Patients’ characteristics, diagnosis, defect size, number of osteotomies, and surgical treatment
Case No. Age/Gender Diagnosis Defect size (mm) No. of osteotomies Surgical treatment
1 65/M Squamous cell carcinoma 78.0 4 Computer-assisted
2 46/F Pseudoarthrosis 68.7 3 Computer-assisted
3 81/M Ameloblastoma 63.9 3 Computer-assisted
4 74/F Squamous cell carcinoma 90.5 3 Computer-assisted
5 20/M Osteosarcoma 79.7 2 Computer-assisted
6 62/M Osteoradionecrosis 60.5 2 Conventional reconstruction
7 59/F Bisphosphonate related
osteonecrosis of the jaw
71.6 3 Conventional reconstruction
8 42/M Osteomyelitis 68.8 2 Conventional reconstruction
9 68/F Osteoradionecrosis 71.1 3 Conventional reconstruction
10 55/F Squamous cell carcinoma 96.8 3 Conventional reconstruction
11 31/M Gunshot wound 78.0 3 Conventional reconstruction
12 41/M Osteomyelitis 68.7 3 Conventional reconstruction
13 76/M Ameloblastoma 63.9 3 Conventional reconstruction
14 53/M Squamous cell carcinoma 90.5 3 Conventional reconstruction
15 42/M Squamous cell carcinoma 89.7 2 Conventional reconstruction
16 44/M Bisphosphonate related
osteonecrosis of the jaw
60.5 2 Conventional reconstruction
17 81/M Squamous cell carcinoma 71.6 2 Conventional reconstruction
18 74/M Squamous cell carcinoma 68.8 2 Conventional reconstruction
19 61/M Keratocyst 71.1 3 Conventional reconstruction
20 55/F Squamous cell carcinoma 66.8 3 Conventional reconstruction
Aesth Plast Surg
123

6. well as the number and sites of osteotomies during surgery
(Fig. 4). The guide’s temporary fixation on the donor site
facilitated the surgical procedure. Use of the surgical guide
for sawing the iliac crest reduced the amount of bone removed
to the required level. In the conventional surgery group, the
harvested amount of bone exceeded the required amount by
on average of 25.3-mm (range = 13.1–33.6 mm).
After harvesting and shaping the iliac crest with the aid
of the surgical guide, the piece fit well into the mandibular
defect of all patients without major adjustments. The aver-
age ischemic time was decreased by 15.6 min (range =
7.3–22.8 min) compared to that of conventional surgery
as a result of the shorter time needed for the shaping
process.
The described method allowed good functional recon-
struction with excellent esthetic outcome of complex areas
of the mandible, such as the chin or the ascending ramus. In
fact, all patients were exceedingly content with their outer
appearance as the contour of the face had good symmetry
and physiognomy was inconspicuous, as if there had not
been any operation at all (Fig. 5). In fact, the mean
assessment score of the esthetic outcome was 88.5-mm
(range = 62.4–96.8 mm) on the visual analog scale for the
patients who underwent computer-assisted treatment com-
pared to 67.9-mm (range = 49.3–81.1 mm) for those in the
conventional surgery group.
No major complications were encountered during the
operation or the healing phase. The flap success rate in our
pilot study was 100% compared to 86.67% for conven-
tional surgical treatment. Two patients have already been
rehabilitated prosthetically using dental implants, which
further increased patient and esthetic satisfaction.
Discussion
Resin templates rendering a virtual plan are reliable tools
to transfer computer models to real-time surgery [8].
Currently, stereolithographic models of the desired iliac
crest bone piece are being used intraoperatively to support
surgery [9]. Common to all current methods is that they use
only a replica. Such an approach may underestimate the
risk of inaccuracies. Mandibular reconstructions using a
custom titanium tray in combination with cancellous iliac
bone grafts [10] or by using a prefabricated titanium
prosthesis [11] have also been described. In these cases,
biological and mechanical stability may cause problems.
A modeling template enables the registration of the
complex 3D curve of the jaw’s contour [12]. With the
methods described herein, it is possible to reconstruct
extensive mandibular defects, primary or secondary, with
good precision and save time. The osteotomies to shape the
Fig. 4 a Preoperative 3D
planning of the reconstruction
of the right mandible with bone
graft from the left iliac crest.
b The result of the
reconstruction is identical to the
virtually determined dimension
and position of the graft
Fig. 5 a Panoramic X-ray
showing dental implants after
computer-assisted
reconstruction of left mandible
with vascularized iliac crest
bone graft. b Esthetically
excellent result after functional
and anatomical reconstruction
with contouring accuracy
Aesth Plast Surg
123

7. transplant were performed on the lateral side of the graft.
The gaps of the osteotomies were filled with cancellous
bone from the donor site. For primary reconstruction a
strict indication is needed because of the impossibility to
intraoperatively extend the surgical plan. Thus, two surgi-
cal guides for two different scenarios can be prepared
beforehand to give the surgeon flexibility during tumor
resection.
By using the planning software it is possible to generate
a 3D image of the vascularization of the donor site.
Therefore, an angiographic CT is needed to investigate the
course of the deep circumflex iliac vessels, which is
important for determining the osteotomies.
A surgical guide transfers the computer-assisted drawn
up surgical plan to real-time surgery. This procedure is
needed in order to realize the benefits of computed-assisted
surgery. The clinical benefit of computer-assisted surgery
is likely to outweigh the cost of the technology [13].
Treatment using a surgery guide reduces the amount of
bone removed which results in lower donor site morbidity,
because postoperative complications increase with the
amount of bone harvested [14]. There is a significant
relationship between ischemic time and survival rate of
flaps [15]. Our method can help keep the ischemic time
period between flap delivery and revascularization to a
minimum. Beyond that, the possible risk of pedicle damage
should diminish as there is no need for extensive handling
during the shaping procedure.
We showed here that using custom-made surgery guides
for mandibular reconstruction with vascularized iliac crest
bone grafts is an effective method for reconstruction,
shortens the operation time, and optimizes not only the
functional but also the esthetic outcome significantly. We
are aware that a randomized prospective trial with a larger
sample size will be required to evaluate further the benefits
of computer-assisted mandibular reconstruction with vas-
cularized iliac crest bone grafts.
Acknowledgment The authors thank Maarten Zandbergen (Mate-
rialise N.V., Leuven, Belgium) for his valuable support.
Conflicts of interest The authors have no conflicts of interest or
financial ties to disclose.
References
1. Cordeiro PG, Disa JJ, Hidalgo DA, Hu QY (1999) Reconstruction
of the mandible with osseous free flaps: a 10-year experience
with 150 consecutive patients. Plast Reconstr Surg 104:
1314–1320
2. Snyder CC, Mateman JM, Davis CW, Warden GD (1970) Man-
dibulo-facial restoration with live osteocutaneous flaps. Plast
Reconstr Surg 45:14–19
3. Disa JJ, Cordeiro PG (2000) Mandible reconstruction with
microvascular surgery. Semin Surg Oncol 19:226–234
4. Riediger D (1988) Restoration of masticatory function by
microsurgically revascularized iliac crest bone grafts using
enosseous implants. Plast Reconstr Surg 81:861–876
5. Kaim AH, Kirsch EC, Alder P, Bucher P, Hammer B (2009)
Preoperative accuracy of selective laser sintering (SLS) in cra-
niofacial 3D modeling: comparison with patient CT data. Rofo
181:644–651
6. Ro EY, Ridge JA, Topham NS (2007) Using stereolithographic
models to plan mandibular reconstruction for advanced oral
cavity cancer. Laryngoscope 117:759–761
7. Hallermann W, Olsen S, Bardyn T, Taghizadeh F, Banic A,
Iizuka T (2006) A new method for computer-aided planning
for extensive mandibular reconstruction. Plast Reconstr Surg
117:2431–2437
8. Liu XJ, Gui L, Mao C, Peng X, Yu GY (2009) Applying com-
puter techniques in maxillofacial reconstruction using a fibula
flap: a messenger and an evaluation method. J Craniofac Surg
20:372–377
9. Juergens P, Krol Z, Zeilhofer HF, Beinemann J, Schicho K,
Ewers R, Klug C (2009) Computer simulation and rapid proto-
typing for the reconstruction of the mandible. J Oral Maxillofac
Surg 67:2167–2170
10. Zhou LB, Shang HT, He LS, Bo B, Liu GC, Liu YP, Zhao JL
(2010) Accurate reconstruction of discontinuous mandible using
a reverse engineering/computer-aided design/rapid prototyping
technique: a preliminary clinical study. J Oral Maxillofac Surg
68:2115–2121
11. Stojadinovic S, Eufinger H, Wehmo¨ller M, Machtens E (1999)
One-step resection and reconstruction of the mandible using
computer-aided techniques – experimental and clinical results.
Mund Kiefer Gesichtschir 3(Suppl 1):151–153
12. Strackee S, Kroon F, Spierings P, Jaspers J (2004) Development
of a modeling and osteotomy jig system for reconstruction of a
mandible with a free vascularized fibula flap. Plast Reconstr Surg
114:1851–1858
13. Ewers R, Schicho K, Undt G, Wanschitz F, Truppe M, Seemann
R, Wagner A (2005) Basic research and 12 years of clinical
experience in computer-assisted navigation technology: a review.
Int J Oral Maxillofac Surg 34:1–8
14. Ghassemi A, Ghassemi M, Riediger D, Hilgers RD, Gerressen M
(2009) Comparison of donor site engraftment after harvesting
vascularized and nonvascularized iliac bone grafts. J Oral Max-
illofac Surg 67:1589–1594
15. Picard-Ami LA, Thomson JG, Kerrigan CL (1990) Critical
ischemia times and survival patterns of experimental pig flaps.
Plast Reconstr Surg 86:739–743
Aesth Plast Surg
123