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SURGICAL ONCOLOGY AND RECONSTRUCTION
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Pek
Ch
ogy
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Outcomes of Orbital Floor ReconstructionAfter Extensive Maxillectomy Using theComputer-Assisted Fabricated Individual
Titanium Mesh Technique
eived
ing Un
ina.
*Reside
yProfeszAssocixProfeskProfes{ProfesThiswo
Comm
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Wen-Bo Zhang, MD,* Chi Mao, MD,y Xiao-Jing Liu, MD,z Chuan-Bin Guo, MD, PhD,xGuang-Yan Yu, MD, DDS,k and Xin Peng, MD, DDS{
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Purpose: Orbital floor defects after extensive maxillectomy can cause severe esthetic and functional de-formities. Orbital floor reconstruction using the computer-assisted fabricated individual titaniummesh tech-
nique is a promising method. This study evaluated the application and clinical outcomes of this technique.
Patients and Methods: This retrospective study included 10 patients with orbital floor defects after
maxillectomy performed from 2012 through 2014. A 3-dimensional individual stereo model based on
mirror images of the unaffected orbit was obtained to fabricate an anatomically adapted titanium mesh us-
ing computer-assisted design and manufacturing. The titanium mesh was inserted into the defect using
computer navigation. The postoperative globe projection and orbital volume were measured and the inci-
dence of postoperative complications was evaluated.
Results: The average postoperative globe projection was 15.91 � 1.80 mm on the affected side and
16.24 � 2.24 mm on the unaffected side (P = .505), and the average postoperative orbital volume was
26.01 � 1.28 and 25.57 � 1.89 mL, respectively (P = .312). The mean mesh depth was 25.11 �2.13 mm. The mean follow-up period was 23.4 � 7.7 months (12 to 34 months). Of the 10 patients, 9did not develop diplopia or a decrease in visual acuity and ocular motility. Titanium mesh exposure was
not observed in any patient. All patients were satisfied with their postoperative facial symmetry.
Conclusion: Orbital floor reconstruction after extensive maxillectomy with an individual titanium meshfabricated using computer-assisted techniques can preserve globe projection and orbital volume, resulting
in successful clinical outcomes.
� 2015 American Association of Oral and Maxillofacial Surgeons
J Oral Maxillofac Surg -:1.e1-1.e15, 2015
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Maxillary defects created after tumor ablation can
cause severe functional and esthetic deformities. The
orbit is located adjacent to the maxillary bone, and
the orbital floor often requires removal, if involved.Orbital floor defects also result in esthetic and func-
tional deformities, including enophthalmos, hypo-
from the Department of Oral and Maxillofacial Surgery,
iversity School and Hospital of Stomatology, Beijing,
nt.
sor.
ate Professor.
sor.
sor.
sor.
rkwas supported by grants from the Science and Technol-
ittee of Beijing, China (Z131107002213116) and the Na-
1.e1
FLA 5.2.0 DTD � YJOMS56896_proof �
phthalmos, diplopia, and impaired visual acuity. The
reconstruction of post-traumatic orbital defects has
been well documented in recent years.1-3 However,
the reconstruction of total orbital floor defects afterextensive maxillectomy remains a challenge
for surgeons.
tional Supporting Program for Science and Technology
(2014BAI04B06).
Address correspondence and reprint requests to Prof Peng:
Department of Oral and Maxillofacial Surgery, Peking University
School and Hospital of Stomatology, Beijing 100081, People’s Repub-
lic of China; e-mail: [email protected]
Received May 27 2015
Accepted June 24 2015
� 2015 American Association of Oral and Maxillofacial Surgeons
0278-2391/15/00906-4
http://dx.doi.org/10.1016/j.joms.2015.06.171
15 July 2015 � 4:05 pm � CE AH
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3
1.e2 COMPUTER-ASSISTED ORBITAL FLOOR RECONSTRUCTION Q1
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Currently, various types ofmaterials, such as titanium
meshes, hydroxyapatite, silica gel, Teflon, and Medpor,
and autogenous bones, such as the iliac and cranial
bones and ribs, are used for orbital reconstruction.4-8
However, reports on the reconstruction of orbital
floor defects resulting from tumor resection are few.
Furthermore, the irregular contour of the orbit makes
it difficult to precisely rehabilitate orbital defects, andcomplications, such as diplopia, malpositioning of the
globe, restriction of ocular motility, and a decrease in
visual acuity, become inevitable in some cases.
Although the use of a titanium mesh, which is flexible
and can easily simulate the orbital bone structure, is
well accepted as the primary choice for orbital
fracture repair, there are no reports on its use for
orbital floor reconstruction after maxillarytumor resection.
Computer-assisted design and manufacturing tech-
niques combined with intraoperative navigation have
been widely used for various craniomaxillofacial sur-
geries.9-11 Preoperative designing and intraoperative
navigation can provide additional accuracy and safety
during orbital floor reconstruction, with improved
clinical outcomes. The aim of this study wasto evaluate the clinical procedure and outcomes
of orbital floor reconstruction after extensive
maxillectomy using the computer-assisted fabricated
individual titanium mesh technique.
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Patients and Methods
PATIENT DEMOGRAPHICS
This retrospective study included 10 consecutivepatients (5 men and 5 women; mean age, 42.1 yr;
Table 1. PATIENT CHARACTERISTICS (N = 10)
Patient
Number Gender
Age
(yr)
Affected
Side
Primary
Diagnosis
Reconstru
Optio
1 F 75 Right Adenocarcinoma ALT
2 M 71 Left Myoepithelial
carcinoma
ALT
3 F 10 Left Ameloblastoma ALT
4 M 51 Right Osteosarcoma FFF
5 F 18 Left Osteofibroma FFF
6 M 9 Left Osteosarcoma RAM
7 F 56 Left Adenoid cystic
carcinoma
ALT
8 M 31 Left Osteofibroma FFF
9 M 75 left Osteosarcoma ALT
10 F 25 Right Myxoma FFF
Abbreviations: ALTF, anterior lateral thigh flap; ANED, alivewithouttherapy; DOD, dead of disease; F, female; FFF, free fibula flap; GKR,rectus abdominis muscle flap.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Max
FLA 5.2.0 DTD � YJOMS56896_proof �
age range, 9 to 75 yr) who underwent orbital floor
reconstruction using an individual titanium mesh
fabricated using computer-assisted techniques after
maxillectomy at the authors’ institution from April
2012 to March 2014. This study followed the Declara-
tion of Helsinki onmedical protocol andwas approved
by the institutional ethic committee and review board.
All patients were diagnosed with maxillary tumorsrequiring resection with extensive maxillectomy
including the orbital floor. The tumors were benign
in 4 patients and malignant in 6. None of the patients
presented with ocular symptoms, such as diplopia,
enophthalmos, impaired visual acuity, and restricted
globe movements. All orbital defects were limited to
the orbital floor. The primary maxillary defects were
restored with a free fibula flap (n = 4), an anteriorlateral thigh flap (n = 5), or a rectus abdominis muscle
flap (n = 1), and the orbital floor defects were recon-
structed with an individual titanium mesh fabricated
using computer-assisted techniques (Table 1).
VIRTUAL SURGICAL PLANNING
All patients underwent spiral computed tomo-
graphic (CT) scanning of the head and neck region
before surgery (field of view, 20 cm; pitch, 1.0; slice,0.75 mm; 120Y280 mA), Qand all imaging data were im-
ported to iPlan CMF (BrainLAB, AG, Feldkirchen, Ger-
many) and ProPlan CMF (Materalise, Leuven,
Belgium). Then, tumor resection and maxillectomy
were simulated on the computer. A 3-dimensional im-
age of the orbital floor was reconstructed from a
mirror image of the unaffected side (Fig 1), after which
a 3-dimensional resin stereo model was printed basedon the mirror image using rapid prototyping
ction
n Recurrence
Adjuvant
Treatment
Follow-Up
(mo) Outcome
F No None 34 ANED
F No None 30 ANED
F Yes Surgery 30 AWD
Yes Rad + chemo 12 DOD
No None 27 ANED
F No None 27 ANED
F Yes Rad + GKR 26 AWD
No None 18 ANED
F No None 16 ANED
No None 14 ANED
evidence of disease; AWD, alivewith disease; chemo, chemo-gamma knife radiosurgery; M, male; Rad, radiotherapy; RAMF,
illofac Surg 2015.
15 July 2015 � 4:05 pm � CE AH
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web4C=FPO
FIGURE 1. Preoperative virtual planning. A, Maxillectomy was simulated on the computer. (Fig 1 continued on next page.)
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
ZHANG ET AL 1.e3
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techniques. The model was used to pre-bend a tita-
nium mesh (0.6 or 0.4 mm; AO CMF, Synthes,
Switzerland) that would be used to rehabilitate the
contour of the orbital floor in each patient (Fig 2).
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SURGICAL PROCEDURE
Tumor resection and maxillectomy were performed
according to the virtual plan completely under the
guidance of a computerized navigation system (Brain-
LAB; Fig 3). The prefabricated titanium mesh was
trimmed and fitted to the orbital floor defect. The po-
sition and depth of the mesh were guided and
controlled by the navigation system (Fig 4). After con-firming the final position, the mesh was fixed to the
nasal bone and zygoma using 4- to 5-mm microscrews.
Extensive maxillary defects were reconstructed with
bony or soft tissue free flaps; the dead space under
FLA 5.2.0 DTD � YJOMS56896_proof �
the mesh was filled by the fat tissue or muscles present
on the flap. The surface of the mesh was completely
covered by the flap tissue.
OUTCOME EVALUATION
All patients were followed for at least 6 months.
Postoperative complications, such as diplopia, restric-
tion of ocular motility, a decrease in visual acuity, and
exposure of the titaniummesh, were evaluated by clin-
ical examination. Facial symmetry was self-evaluated
and scored by the patients, and the results were classi-
fied as satisfactory (8 to 10), fair (4 to 7), and poor (0 to
3). The postoperative globe projection and orbital vol-ume on the reconstructed and unaffected sides were
measured using iPlan CMF (BrainLAB) based on the
spiral CT images obtained 6 months after the primary
surgery. Globe projection was measured on an axial
15 July 2015 � 4:05 pm � CE AH
web4C=FPO
FIGURE1 (cont’d). B, The mirror image of the unaffected side was used to rehabilitate the contour of the orbital floor and facial symmetry.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
1.e4 COMPUTER-ASSISTED ORBITAL FLOOR RECONSTRUCTION
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slice with the largest diameter of the eye globe. A base-line was drawn from the anterior point of the lateral
orbital rim to the median sagittal line, and the distance
from the most projecting point of the cornea to the
baseline was defined as the globe projection (Fig 5).
Orbital volumewasmeasured based on a series of axial
CT slices. The bony border between the optic nerve fo-
ramen and the connecting line between the zygomati-
cofrontal suture and the nasomaxillary suture wereoutlined, and the volume of the outlined area was
calculated as the orbital volume using a computer
(Fig 6). The depth of the titanium mesh also was
measured on a sagittal CT slice. The distance from
the orbital rim to the deepest point at the posterior
end of the titanium mesh was defined as the depth
of the titanium mesh (Fig 7).
Differences in globe projection and orbital volumebetween the unaffected and reconstructed sides
FLA 5.2.0 DTD � YJOMS56896_proof � 15 July 2015 � 4:05 pm � CE AH
were determined using paired sample t tests with SPSS17.0 (SPSS, Inc, Chicago, IL). A P value less than .05
was considered statistically significant.
Results
Themean follow-up durationwas 23.4� 7.7months
(range, 12 to 34months). During the follow-up period,
1 patient developed a local recurrence of adenoid
cystic carcinomawith invasion of the extraocular mus-
cles and extension to the intracranial area. Distant
metastasis to the lung also was detected. This recur-
rence resulted in postoperative diplopia and visualproblems. Salvage treatment was performed using
gamma knife radiosurgery, and the patient survived
with the tumor until the end of follow-up. Another pa-
tient who presented with recurrent osteosarcoma in
web4C=FPO
FIGURE 2. Fabricated individual titanium mesh. A 3-dimensional stereo model based on the mirror plan was printed using the rapid prototyp-ing technique to fabricate an individual titanium mesh to reconstruct the orbital floor of the affected side.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
ZHANG ET AL 1.e5
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the inferior temporal fossa and received salvage che-
moradiotherapy died of the disease a year after the pri-
mary surgery, and a young patient with an
ameloblastoma who presented with local recurrence
in the infraorbital region 14 months after the primarysurgery underwent titaniummesh removal with tumor
resection in the secondary surgery. However, neither
of these 2 patients complained of specific complica-
tions, such as diplopia or a decrease in visual acuity
and ocular motility, before tumor recurrence (Table 2).
Thus, 9 of the 10 patients exhibited normal visual
acuity and ocular motility after orbital floor recon-
struction. There was no mesh rejection or exposurein any of the 10 patients (Table 2). Globe projection
was 15.91 � 1.80 mm on the reconstructed side and
16.24 � 2.24 mm on the unaffected side (P = .505).
The orbital volume was 26.01� 1.28 mL on the recon-
structed side and 25.27 � 1.89 mL on the unaffected
side (P = .312). The 2 parameters showed no statistical
differences between the reconstructed and unaffected
sides, consistent with the clinical findings of no post-operative diplopia or enophthalmos (Table 3). The
mean depth of the titanium mesh was 25.11 �2.13 mm, with no indication of damage to the optic
nerve. All patients were satisfied with their postopera-
tive facial symmetry (Fig 8, Table 2).
FLA 5.2.0 DTD � YJOMS56896_proof �
Discussion
Maxillary defects after trauma or tumor resection
can cause severe functional and esthetic disturbances.The orbital floor forms the roof of the maxilla and is
usually involved in extensive maxillectomy for midfa-
cial tumors. The orbital floor is a very important
bony structure in the midfacial region that is respon-
sible for supporting the eye globe, midfacial projec-
tion, and facial symmetry. Orbital floor defects also
result in various deformities and functional distur-
bances, such as diplopia, enophthalmos, restrictionof globe movement, a decrease in visual acuity, and
depression of the infraorbital region. The reconstruc-
tion of post-traumatic orbital defects has been well
documented in recent years.1-3 However, the
reconstruction of total orbital floor defects after
extensive maxillectomy remains a challenge
for surgeons.
Several materials and methods have been used for
orbital floor reconstruction, including autogenousbone grafts, alloplastic materials, and other manufac-
tured materials.4-8,12-14 Previous studies have
reported the use of nonvascularized autogenous
bones, such as the iliac bone, ribs, and calvaria, as
grafts for orbital floor reconstruction.15,16 However,
15 July 2015 � 4:05 pm � CE AH
web4C=FPO
FIGURE 3. Intraoperative navigation-guided tumor resection and maxillectomy. A, The intraoperative navigation system was used to controlthe accuracy of the surgery. B, The probe was used to detect the points on the bone. C, The navigation system showed the exact position of theosteotomy plane as the virtual plan before surgery.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
FLA 5.2.0 DTD � YJOMS56896_proof � 15 July 2015 � 4:05 pm � CE AH
1.e6 COMPUTER-ASSISTED ORBITAL FLOOR RECONSTRUCTION
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web4C=FPO
FIGURE4. Intraoperative navigation-guided titaniummesh placement. The titaniummeshwasA, trimmed and B, placed into the defect.C, Thenavigation provided the position and depth guidance. B, Afterward, the mesh was fixed to the nasal bone and zygoma.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
FLA 5.2.0 DTD � YJOMS56896_proof � 15 July 2015 � 4:05 pm � CE AH
ZHANG ET AL 1.e7
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FIGURE5. Globe projection measurements. An axial slice with the largest diameter of the eye globe is obtained using spiral computed tomog-raphy. Then, a baseline is drawn from the anterior point of the lateral orbital rim to the median sagittal line. The distance from the most projectingpoint of the cornea to the baseline is defined as the globe projection.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
1.e8 COMPUTER-ASSISTED ORBITAL FLOOR RECONSTRUCTION
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the rate of infection and resorption with these
materials is high. In addition, donor-site morbidity is
a potential disadvantage of these materials. The goals
of orbital floor reconstruction include restoration of
the shape and framework of the orbit, provision of
support and maintenance of the position of the eye
globe, rehabilitation of the orbital volume, and restora-
tion of facial esthetics. However, the thinness andirregular contour of the orbit make it difficult to find
an appropriate material for precise reconstruction of
orbital defects, and complications, such as diplopia,
enophthalmos, and restriction of ocular mobility,
become inevitable in some cases.
Titanium meshes are commonly used for recon-
struction of the midface and skull base defects after
ablative surgery and trauma, and they are currentlythe first choice of material for post-traumatic orbital
reconstruction.17-19 Convenience of fabrication,
stability, flexibility, no donor-site morbidity, and a
decreased surgical duration have increased the popu-
larity of titanium meshes for maxillofacial surgeries.
However, there are some differences between post-
traumatic orbital floor reconstruction and postmaxil-
lectomy orbital floor reconstruction.
FLA 5.2.0 DTD � YJOMS56896_proof �
The major difference between the 2 procedures is
the extent of the defect. Complex midfacial defects,
including the maxilla, part of the zygoma, and the
orbital floor, always remain after tumor resection and
maxillectomy as opposed to small defects, including
the orbital walls, after post-traumatic surgery. Exten-
sive defects require a completely different clinical pro-
tocol for reconstruction. As an example, a much largertitanium mesh is required, in addition to a free flap
with enough volume for reconstruction of the maxil-
lary defect and prevention of mesh exposure. In the
present study, a large prefabricated titanium mesh
was used to cover the entire orbital floor defect in
each patient. A free fibula flap (n = 4), an anterior
lateral thigh flap (n = 5), and a rectus abdominis mus-
cle flap (n = 1) were used for complex defects. Allthese flaps included an adequate soft tissue volume
(fat tissue or muscles) to fill in the defects and shield
the titanium mesh.
The success of orbital floor reconstruction with a ti-
tanium mesh depends on 2 critical factors. First is the
restoration of the shape of the individual orbital floor,
and second is the definition of the appropriate posi-
tion of the titanium mesh, including the level and
15 July 2015 � 4:05 pm � CE AH
web4C=FPO
FIGURE 6. Orbital volume measurements. A series of axial computed tomographic slices is obtained. A, Then, the bony border between theoptic nerve foramen and the connecting line between the zygomaticofrontal suture and the nasomaxillary suture is outlined. B, The orbitalvolume is calculated by the computer.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
FLA 5.2.0 DTD � YJOMS56896_proof � 15 July 2015 � 4:05 pm � CE AH
ZHANG ET AL 1.e9
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FIGURE 7. Measurement of the depth of the titanium mesh. A sagittal slice of the deepest position of the titanium mesh is obtained using post-operative computed tomography. The depth of the titaniummesh is calculated as the distance from the orbital rim to the posterior end point of thetitanium mesh.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
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depth. Preoperative virtual surgical planning and intra-
operative navigation provide a useful solution to
achieve these requirements. These computer-assisted
protocols have been widely used for various types ofcraniomaxillofacial surgeries, including osteotomy, or-
Table 2. OUTCOMES OF ORBITAL FLOOR RECONSTRUCTIONUSING COMPUTER-ASSISTED TECHNIQUES
Patient
Number
Primary
Diagnosis
Depth of Titanium
Mesh (mm) Diplopia
1 Adenocarcinoma 26.12 No N
2 Myoepithelial
carcinoma
21.03 No N
3 Ameloblastoma 25.32 No N
4 Osteosarcoma 24.26 No N
5 Osteofibroma 22.04 No N
6 Osteosarcoma 25.06 No N
7 Adenoid cystic
carcinoma
27.24 Yes A
8 Osteofibroma 26.56 No N
9 Osteosarcoma 27.46 No N
10 Myxoma 26.01 No N
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Max
FLA 5.2.0 DTD � YJOMS56896_proof �
thognathic surgery, fracture reduction, and bony flap
reconstruction.20,21 Zhang et al19 and Yu et al22 used
this procedure for post-traumatic orbital wall recon-
struction and achieved satisfactory clinical outcomes.Therefore, in the present study, the outcomes of this
USING AN INDIVIDUAL TITANIUM MESH FABRICATED
Postoperative Complications
Ocular
Mobility
Visual
Acuity
Titanium
Mesh Exposure Facial Symmetry
ormal Normal No Satisfactory
ormal Normal No Satisfactory
ormal Normal No Satisfactory
ormal Normal No Satisfactory
ormal Normal No Satisfactory
ormal Normal No Satisfactory
bnormal Decrease No Satisfactory
ormal Normal No Satisfactory
ormal Normal No Satisfactory
ormal Normal No Satisfactory
illofac Surg 2015.
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Table 3. POSTOPERATIVE GLOBE PROJECTION AND ORBITAL VOLUME
Reconstructed Side Unaffected Side Difference P Value
Postoperative globe
projection (mm)
15.91 � 1.80 16.24 � 2.24 0.34 � 1.53 .505
Postoperative orbital
volume (mL)
26.01 � 1.28 25.57 � 1.89 0.44 � 1.29 .312
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
web4C=FPO
FIGURE8. Q7Clinical outcome of a selected case.A-C, The patient had extensive recurrent ameloblastoma of the left maxilla with the orbital floorinvolved and she underwent left maxillectomy including the orbital floor. (Fig 1 continued on next page.)
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
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web4C=FPO
FIGURE8 (cont’d). D-F, Using the computer-assisted individual fabricated titaniummesh technique with free fibula flap reconstruction, a sym-metrical appearance was achieved and normal function of the globe was preserved after surgery.
Zhang et al. Computer-Assisted Orbital Floor Reconstruction. J Oral Maxillofac Surg 2015.
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technique were evaluated in patients who underwent
orbital floor reconstruction after extensive
maxillectomy.
All tumor-related orbital defects in this study were
unilateral, and all defects were limited to the orbital
floor without involvement of the other orbital walls.
Therefore, rehabilitation of the individual position
and contour of the orbital floor using a computerizedmirror image of the unaffected side was ideal,
presuming individual symmetry of the facial bone struc-
ture. Although measurable differences in facial symme-
try exist in all individuals, the differences are small and
minor in appearance and function.21,23 An essential
parameter for maxillary reconstruction with good
esthetic results is recovery of the contour and volume
of the maxilla. In this study, an individual fabricatedtitanium mesh not only supported the eye globe but
also rehabilitated the contour and projection of the
infraorbital region. Furthermore, the soft tissue on
the flaps filled the dead space under the titanium
mesh and restored the volume of the defects. Esthetic
results were assessed by the patients and surgeons,
who were satisfied with the postoperative facial
symmetry in all cases.The normal position of the eye globe is maintained
by a balance between the orbital volume and the intra-
orbital soft tissue. A disturbance in this balance from
expansion of the orbital volume or a decrease in the
orbital contents can lead to enophthalmos.19 In most
post-traumatic cases, particularly those of delayed
orbital fracture repair, changes in the orbital volume
and globe projection develop because of absoluteexpansion of the orbital volume or a decrease in the
orbital contents. Enophthalmos is always the chief
complaint of such patients. The role of the titanium
mesh is to restore the orbital volume and globe projec-
tion by anatomic reconstruction.19 However, during
reconstruction of the orbital floor after tumor resec-
tion, the periorbital fat pad and extraocular muscles
are preserved. In general, there are no changes in theorbital contents, and the purpose of the titanium
mesh is to maintain the anatomic position of the orbital
floor. In the present study, the orbital contents and ex-
traocular muscles were preserved during primary sur-
gery in all patients, none of whom complained about
preoperative enophthalmos or problems with visual
acuity and ocular motility. Therefore, rehabilitation of
the orbital volume was critical for normal function ofthe eye globe. Migliori and Gladstone24 measured the
globe projection in 681 patients without any orbital le-
sions and found that the difference was less than 2 mm
in all patients. Koo et al25 also reported that clinically
important enophthalmos can be evaluated by differ-
ences in globe projection, with a difference less than
2 mm considered clinically minor. Some investigators
have developed the relation between changes in the
FLA 5.2.0 DTD � YJOMS56896_proof �
orbital volume and changes in the globe projection or
enophthalmos.19,26,27 Sun et al28 reported the use of
a fabricated titanium mesh for orbital floor reconstruc-
tion after maxillectomy in 19 patients, although a nav-
igation protocol was not included and there was no
related analysis of the postoperative globe projection
and orbital volume. The results of the present study
indicated no statistical differences in the orbital volumeand globe projection between the reconstructed and
unaffected sides. Postoperative examinations also
showed a low rate of complications, such as diplopia
and restriction of ocular motility.
Preservation and protection of the optic nerve are
essential for any orbital surgery. The depth of the in-
serted implant should always be accurate. In post-
traumatic cases, the depth of the implant depends onthe position of the fracture. Therefore, the implant is
occasionally inserted very deeply and close to the
apex. Zhang et al19 reported 21 post-traumatic cases
in which an individual fabricated titanium mesh was
used for orbital wall reconstruction, with an implant
depth of 29.33 mm. However, the depth of the implant
after tumor resection depends on the extent of the de-
fects. In the present study, the optic nerve was notaffected in any patient, and no patient complained
about problems with visual acuity before surgery. CT
scanning showed a safe distance existed between the
apex and the tumor. Therefore, the posterior region
of the orbital floor close to the apex remained during
tumor resection. The depth of the titanium mesh in
the present series was 25.11 mm,which was shallower
than that reported for post-traumatic cases. As reportedpreviously for post-traumatic reconstruction,22,26,27
the depth of the implant can be controlled by
intraoperative navigation. By matching the contour of
the mobile segment with the preoperative virtual
plan, the individual fabricated titanium mesh can be
inserted into the ideal position, after which the
orbital apex can be checked to determine
overextension. Thus, surgical safety can be obtainedby navigation. According to the present results, no
visual impairment associated with mesh insertion
was recorded.
Although titaniummesh is an ideal choice for orbital
floor reconstruction, some risks remain. The major
risk is infection and exposure of the titanium mesh,
particularly in patients with malignant tumorswho un-
dergo adjuvant radiotherapy. The presence of hypo-vascular irradiated tissue and extensive fibrosis that
progresses after radiotherapy considerably increases
the risk of infection and exposure of the titanium
mesh.28-31 Several previous studies have reported the
use of the titanium mesh and soft tissue flaps or free
bone grafts for maxillary reconstruction; infections
and exposure were not uncommon in these
studies.29-31 Nakayama et al30 reported radiotherapy-
15 July 2015 � 4:05 pm � CE AH
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related titanium mesh exposure in 27.8% of patients
who underwent maxillary reconstruction with soft tis-
sue flaps and a titanium mesh. Sun et al31 used a radial
forearm flap and a titanium mesh for maxillary and
orbital floor reconstruction and reported exposure in
15.8% of patients (3 of 19) during the follow-up
period. An inadequate soft tissue volume for covering
the mesh is responsible for these complications. In thepresent patients, a titanium mesh was used with free
flaps containing an adequate soft tissue volume, such
as an anterior lateral thigh flap, a rectus abdominis
muscle flap, or a free fibula flap with the flexor hallucis
longus. Furthermore, 2 of the 5 patients with malig-
nancies received radiotherapy, none of whom ex-
hibited mesh exposure or infection during long-term
follow-up.In this study, a preliminary clinical protocol was pro-
vided for the application of an individual fabricated ti-
tanium mesh for reconstruction of tumor-related
orbital floor defects. Although satisfactory clinical re-
sults were achieved, some limitations should be noted.
Although the use of a titaniummesh for reconstruction
after the resection of benign tumors can be well
accepted, its use for reconstruction after the resectionof malignant tumors remains controversial and re-
quires long-term follow-up data. In addition, the error
of the navigation technique should be considered.
The technical accuracy of the navigation system used
in this study is reportedly less than 1 mm, with an
intraoperative accuracy less than 2 mm for some pa-
tients.32-34 Therefore, the results are acceptable
according to these values. However, various factorsinfluence this accuracy, including the imaging
resolution, accuracy of registration, and accuracy of
the computer algorithm.35 Further prospective studies
with a larger sample are required to clarify these issues.
The results of this study suggest that orbital floor
reconstruction after extensive maxillectomy using
the computer-assisted fabricated individual titanium
mesh technique is a feasible and acceptable proce-dure. Intraoperative navigation combined with preop-
erative virtual surgical planning can precisely preserve
the globe projection and orbital volume; furthermore,
complications such as diplopia, restriction of ocular
motility, and a decrease in visual acuity can be pre-
vented, thus resulting in successful clinical outcomes.
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