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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_660_Библиотеки_им_академика_М_И_Перельмана
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Chapter 7 Internal orbit
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A B
Fig. 7.7 (A) Defect of orbital oor. (B) Orbital oor reconstructed with graft spanning the defect. Stable adjacent ledges make bone graft or
implant positioning relatively straightforward.
When reconstructing injuries to one orbital wall, the surgeon first defines
the defect by identifying intact bone edges and then spans the defect with
an implant or autogenous graft (Fig. 7.7). The size of the defect and the
normal configuration of the injured area will dictate the dimensions, thickness, and number of grafts. For example, a small floor defect is usually
reconstructed with a single thin implant, replicating the relatively flat shape
of the orbital floor. A similarly dimensioned inferomedially located defect
usually requires a thick implant or stacked implants to recreate the convex
shape of the orbit in this area. Failure to replicate this convexity effectively
increases the volume of the orbit from normal and tends towards enophthalmos. Similarly, placement of an overly thick implant to reconstruct the floor
would also create an internal orbit shape different from normal. In this case,
the abnormal convexity beneath the globe would elevate it, resulting in an
ocular dystopia. For injuries involving only the floor, the senior author routinely uses an alloplastic implant. Implants are immobilized with titanium
screws.
Injuries involving two or more walls of the orbit are problematic. Rigid fixation techniques allow these complex injuries to be subdivided into a series of
smaller, more manageable areas for reconstruction. Implants designed to mimic
the contours of the orbital floor and medial wall allow combined floor and
medial wall injuries to be reconstructed with a single implant13 (Fig. 7.8).
Implant materials
Materials available for reconstruction include bone, cartilage, smooth and
porous plastics, as well as metal.
Reconstruction with autogenous bone has the conceptual advantage
that it will, in time, become vascularized and incorporated into the skeleton, thereby resisting migration, extrusion, and infection. Revasculariza-
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tion, however, also predisposes the graft to resorb, with a concomitant
PEARL
Denition of intact skeletal ledges is
key to placing implants.
Operative technique
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Fig. 7.8 Method of spanning large orbital defects. Titanium mesh is
molded to the appropriate contour, bridges the defect, and is xed to the
orbital rim. The mesh, often coated with porous polyethylene, may serve
as a platform for additional implant placement.
change in internal orbit architecture – hence, volume and globe position.
Clinical experience has shown that cranial grafts tend to resorb less than
grafts taken from other donor sites. Cranial bone grafts have more dense
cortical bone than ilium or rib, which tend to be predominantly cancellous.
Experimental evidence suggests that the volume persistence of cranial grafts
may result from the fact that cortical bone is less susceptible to revascularization than cancellous bone, thus less susceptible to osteoclastic activity
(see Chapter 3).14 Cranial bone can be difficult to shape and control during
internal orbit reconstruction.
To avoid changes in graft shape and volume, as well as to avoid the
morbidity and operative time associated with autogenous graft harvest,
alloplastic implants have long been used for orbital floor reconstruction.
These include polytetrafluoroethylene (PTFE), silicone, dense and porous
polyethylene, resorbable materials, metal plates, and polymethylmethacrylate. High rates of extrusion have been documented for the rigid smoothsurfaced implants made of silicone (3.1%) and nylon (12%). There are also
many reports of late complications, especially with silicone, PTFE, and nylon
plates. These have been noted to occur as late as 21 years after placement,
and include infection, extrusion, migration with hematoma formation, and
lower eyelid deformity.15 Clinical experience obtained from treating these
complications suggests that these problems are related to capsule formation
around smooth-surfaced implants with the concomitant tendency towards
implant migration.
Porous polyethylene is the senior author’s preferred non-metallic orbital
implant. In a personal experience with over 200 patients since 1987, there has
been no known instance of infection or graft extrusion using this material for
internal orbit reconstruction. Clinical experience suggests that the soft tissue
ingrowth into the material limits the tendency for migration seen with smoothsurfaced implants. Others have presented anecdotal data suggesting that
this soft tissue ingrowth has the potential to include adjacent ocular motility
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Chapter 7 Internal orbit
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Fig. 7.9 A exible titanium infrastructure is laminated with porous
polyethylene. Courtesy Matrix Surgical, Atlanta, GA.
muscles with the possibility of ocular motility disorder. To avoid this potential
problem, polyethylene implants are now available with a smooth surface on the
inner side of the orbit and a porous surface on the other. The smooth surface
is designed to face the orbital soft tissue contents and the porous side to face
the sinuses. The smooth surface is intended to prevent soft tissue ingrowth and
possible motility problems, while the porous side allows soft tissue ingrowth
with concomitant immobilization.
Laminated implants of titanium metal and polyethylene are available (Fig.
7.9). A titanium infrastructure is sandwiched between a sheet of smooth poly-
ethylene on one side and a sheet of porous polyethylene on the other. The metal
facilitates implant conformability and screw fixation. The smooth laminate is
intended to interface with the soft tissue while the porous laminate is intended
to interface with the mucosal surface.
Video 7.1 demonstrates the reconstruction of an orbital floor blowout frac-
ture using a titanium mesh implant.
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CLINICAL EXAMPLES
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Clinical examples of patients treated with the techniques described are presented in Figs. 7.10 and 7.11).
A
Clinical examples
B
D
E
C
F
Fig. 7.10 A 30-year-old man was assaulted with a pipe. Surgery was performed through coronal, transconjunctival with lateral canthotomy,
and intraoral incisions. The internal orbit was reconstructed with titanium mesh. (A) Preoperative coronal CT scan. (B) Preoperative sagittal
CT scan. The arrow points to the intact ledge of the posterior orbital oor discussed in Fig. 7.6. (C) Postoperative coronal CT scan. (D)
Postoperative sagittal CT scan. (E) Postoperative axial CT scan. (F) Postoperative three-dimensional CT scan. (G) Postoperative worm’s eye
view.
G
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Chapter 7 Internal orbit
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A
C
E
B
D
F G
Fig. 7.11 A 32-year-old woman was struck by an automobile and suered multiple injuries including a right orbital fracture. The internal
orbit was not reconstructed acutely and the patient developed enophthalmos as well as a loss of malar prominence. The patient presented
for secondary reconstruction 9 months after her initial repair. Surgery was performed through a transconjunctival retroseptal with lateral
canthotomy and intraoral incisions. The internal orbit as well as the lateral and inferior orbital rims were reconstructed with porous
polyethylene implants immobilized with titanium screws. (A) Preoperative frontal view. (B) Postoperative frontal view. (C) Preoperative
worm’s eye view. (D) Postoperative worm’s eye view. (E) Three-dimensional CT scan showing initial reconstruction. (F) Preoperative coronal
CT scan showing enlarged, unrepaired internal orbit. (G) Intraoperative view of internal orbit reconstruction with screw-immobilized porous
polyethylene implants.
REFERENCES
1. Bite U, Jackson IT, Forbes GS, et al. Orbital measurements in enophthalmos using threedimensional CT imaging. Plast Reconstr Surg 1985;75:502–11.
2. Manson PN, Clifford CM, Su CT, et al. Mechanisms of global support and posttraumatic
enophthalmos. I. The anatomy of the ligament sling and its relation to intramuscular cone
orbital fat. Plast Reconstr Surg 1985;77:193–200.
3. Manson PN, Grivas A, Rosenbaum A, et al. Studies on enophthalmos. II. The measurement of
orbital injuries and their treatment by quantitative computed tomography. Plast Reconstr Surg
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1985;77:201–9.
4. Hawes MJ, Dortzbach RK. Surgery on orbital floor fractures (influence of time and repair and
fracture size). Ophthalmology 1983;90:1066–72.
5. Wilkins RB, Havins WE. Current treatment of blowout fractures. Ophthalmology 1982;89:464–72.
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6. Yaremchuk MJ, Kim WK. Soft tissue alterations with acute, extended open reduction and
internal fixation of orbital fractures. J Craniofac Surg 1992;3:134–40.
7. Glassman RD, Manson PN, Petty P, et al. Techniques for improved visibility and lid protection
in orbital explorations. J Craniofac Surg 1990;1:69–72.
8. Tessier P. Inferior orbitotomy. A new approach to the orbital floor. Clin Plast Surg 1982;9:569–75.
9. Romano J, Iliff N, Manson PN. Use of Medpor porous polyethylene implants in 140 patients
with facial fractures. J Craniofac Surg 1993;4:142–50.
10. Glassman RD, Manson PN, Vanderkolk CA, et al. Rigid fixation of internal orbital fractures.
Plast Reconstr Surg 1990;86:1103–10.
11. Rubin PAD, Shore JW, Yaremchuk MJ. Complex orbital fracture repair using rigid fixation of
the internal orbital skeleton. Ophthalmology 1992;99:553–61.
12. Yaremchuk MJ, Manson PN. Reconstruction of the internal orbit using rigid fixation
techniques. In: Yaremchuk MJ, Gruss JS, Manson PN, editors. Rigid fixation of the
craniomaxillofacial skeleton. Boston: Butterworth-Heinemann; 1992.
13. Gordon CR, Susarla SM, Yaremchuk MJ. Quantitative assessment of medial orbit fracture
repair using computer-designed anatomical plates. Plast Reconstr Surg 2012;130(5):698e–705e.
14. Chen NT, Glowacki J, Bucky LP, et al. The roles of revascularization and resorption on
endurance of craniofacial onlay bone grafts in the rabbit. Plast Reconstr Surg 1994;93:725–82.
15. Rubin JP, Yaremchuk MJ. Complications and toxicities of implantable biomaterials used in
facial reconstructive and aesthetic surgery: a comprehensive review of the literature. Plast
Reconstr Surg 1997;100:1336–53.
References
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Video 7.1 Orbital oor repair. This video demonstrates the reconstruction of an orbital oor
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blowout fracture using a titanium mesh implant. Forced duction tests at onset and nish of
surgery demonstrate soft tissue entrapment and subsequent release, respectively.
86.e1
Chapter 8
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Infraorbital rim
The upper midface skeleton has direct and indirect influences on the appearance of the face and, particularly, the eyes. The relationship between the globe
and the orbital rims will determine if the eyes appear prominent or deep set.
Because the infraorbital rim and upper midface skeleton support the lower
eyelids and the cheek soft tissues, their projection impacts on lid and cheek
position. Patients with deficient skeletons are more likely to undergo premature lower lid and cheek descent with aging. This lack of skeletal support predisposes to lower lid malposition after blepharoplasty and limits the efficacy
and longevity of midface lifting. This chapter demonstrates the impact that
infraorbital rim augmentation alone, or together with other soft tissue manipulations, has on periorbital appearance. It includes techniques not only for
augmenting the infraorbital rim with alloplastic implants, but also for elevating the midface soft tissues as well as repositioning the lower lid and lateral
canthus.
GLOBE–RIM RELATIONS
The relationship of the globe to the orbital rims is a primary determinant of
the appearance of the upper third of the face. Normal values, that is, averages
calculated from a cohort of young, healthy adults, have been published. They
are presented in Fig. 8.1.
the supraorbital rim lies 10 mm anterior to the cornea, and the surface of the
Fig. 8.1 Sagittal relations of the anterior surface of the cornea to the soft
tissues overlying the supraorbital and infraorbital rims. On average, in the
young adult, the supraorbital rim projects 10 mm beyond, the infraorbital
rim lies 3 mm behind, and the cheek prominence projects 2 mm beyond the
anterior surface of the cornea.
1–4
On average, the surface of the soft tissues overlying
1–4
10 mm
3 mm
2 mm
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Chapter 8 Infraorbital rim
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soft tissues overlying the infraorbital rim lies 3 mm behind the anterior surface
of the cornea. This implies that the supraorbital rim usually projects 13 mm
beyond the infraorbital rim. When the orbital rims have a greater projection
beyond the anterior surface of the cornea, the eyes appear “deep set.” When
the orbital rims project less, the eyes appear “prominent.” In addition to being
predisposed to corneal exposure-related problems, overly prominent eyes are
usually considered less attractive.
Jelks’ vector analysis
Jelks and Jelks5 categorized globe–orbital rim relationships and the tendency
for the development of lower lid malposition after blepharoplasty (Fig. 8.2). On
sagittal view, they placed a line or “vector” between the most anterior projection of the globe and the malar eminence and lid margin. A “positive vector”
relationship exists when the most anterior projection of the globe lies behind the
soft tissues overlying the midface skeleton in the parasagittal plane. A “negative vector” relationship exists when the most anterior projection of the globe
lies beyond the soft tissues overlying the midface skeleton in the parasagittal
plane. This relation reflects a deficiency in midface projection. Jelks and Jelks
warned, similar to Rees and LaTrenta,6 that patients whose orbital morphology
has a “negative vector” relationship are morphologically prone to lid malposition after lower blepharoplasty.
There is a considerable variability in globe–orbital rim relations as a result
of the wide variations in human facial skeleton morphology. It is influenced by
ethnicity and sex, and changes with aging.
Migliori and Gladstone7 determined the normal range of globe protrusion for
white and black adults. Using the Hertel exophthalmometer, which measures
projection of the anterior surface of the cornea beyond the lateral orbital rim,
they found that the range for white adults was 10 mm; for black adults it was
12 mm. In addition to determining a range of normal values, they documented
racial and sexual differences in globe projection. When globe projection was
Positive vector
A B C
Fig. 8.2 Jelks and Jelks5 categorized globe–orbital rim relationships by placing a line or “vector” between the most anterior
projection of the globe and the soft tissues overlying the midface skeleton in the parasagittal plane. (A) Positive vector
relationship. (B) Negative vector relationship. (C) “Reversed” negative vector relationship resulting from increasing the sagittal
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projection of the infraorbital rim with an implant. After Yaremchuk 2003.
Negative vector “Reversed” negative vector
Implant
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