Executive Editor: Edward Ellis III, Kazuo Shimozato General Editor: Daniel Buchbinder

Authors: Carl-Peter Cornelius, Nils Gellrich, Søren Hillerup, Kenji Kusumoto, Warren Schubert, Coauthors: Enno-Ludwig Barth, Harald Essig

Midface - Medial orbital wall - Orbital reconstruction

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Glossary

1 Emergency treatment top

Emergency treatment in midfacial fractures may be indicated in the following cases:

  • Partial or complete visual loss due to direct or indirect optic nerve trauma
  • Severely increased intraocular pressure
  • Acute space-occupying lesion (eg, retrobulbar hematoma, emphysema)
  • Severe shift of orbital content
  • Entrapment of eye muscle (particularly in pediatric patients)
  • Severe nasal and/or oral bleeding

Globe rupture and intraocular trauma

There are a variety of possible injuries affecting the globe that may require immediate ophthalmological treatment.


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Retrobulbar hematoma

Pressure increase in the periorbital region due to retrobulbar hematoma can cause significant injury of the neurovascular structures with eventual loss of vision.

Note: Intraorbital bleeding in patients taking anticoagulation drugs requires special attention.


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If a retrobulbar hematoma leads to a tense, proptotic globe, emergency decompression should be considered.

If a retrobulbar hematoma in the cooperative patient results in blindness, the time window to release the intraorbital pressure is limited to around one hour measured from the onset of blindness. This could mean urgent treatment under local anesthesia even in the emergency room prior to further imaging.

Transcutaneous transseptal incisions may help evacuate the hematoma and release the periorbital pressure. Alternative methods such as transconjunctival pressure release and/or lateral canthotomy and inferior cantholysis should be considered according to patient condition.

An exception may be where there is a pulsating exophthalmos which may be a sign of carotid-cavernous sinus fistula. A fistula of this nature requires appropriate preoperative imaging.

Note: retrobulbar hematoma is one of the most severe postoperative complications in patients who have undergone orbital trauma and/or surgery. This is one reason why the surgeon has to assess appropriate vision as soon as possible after injury and/or surgery.


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Emphysema

Severe emphysema might significantly raise intraorbital pressure. If this compromises visual function or endangers the orbital contents, orbital decompression has to be considered. Drug protocol may include antibiotics and decongestive nasal drops.

Patients with sinus fractures in the periorbital region should not blow their nose in order to avoid additional emphysema due to acute pressure rise. Should sneezing occur, maintaining an open mouth posture minimizes increasing intranasal/intrasinus pressure.


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Usually there is no need for emergency treatment in orbital floor/medial wall fractures unless there is severe ongoing hemorrhage in the orbital cavity, the paranasal, or nasal cavity.
In some younger patients, the so-called trap-door phenomenon can occur in which there is danger of necrosis of the entrapped rectus muscle within a few hours; immediate release of entrapped tissues is necessary.

Entrapment of eye muscle (especially in children)
The inferior rectus muscle is the most common ocular muscle to become entrapped with an orbital floor fracture (trap-door phenomenon) and this may not be visible on conventional x-rays. Entrapment requires urgent freeing of the muscle to prevent necrosis of the incarcerated muscle. Clinical examination should give evidence on impaired ocular muscle function. Entrapment is often associated with severe ocular pain on attempted range of motion, as well as nausea and vomiting, especially in children.
Note: In children, entrapment of the eye muscles is more common than in adults; this might be due to the higher elasticity of the bony structures (green-stick fractures are more common).


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Bone fragments affecting the optic nerve

Special attention has to be paid to the posterior third of the orbit and the bony optic canal. Bony dislocations in these anatomical areas are more likely to be associated with traumatic optic nerve lesions.

Axial CT scan in the plane of the optic nerve shows multiple fractures of the lateral orbital wall and the greater wing of the sphenoid of the right side. Additional stretching of the right optic nerve is present. Fractures where fragments involve the posterior third of the orbit are susceptible to subsequent optic nerve disorders.


Severe bleeding

In case of severe bleeding the following options should be considered:

  • Assessment of current medical treatment for anticoagulation such as Coumadin, Aspirin, or other anti-platelet medication.
  • Compression: either by nasal packing, balloon tamponade, or direct compression.
  • Electrocautery: if a clear bleeding source can be evaluated.
  • Control and adjustment of blood pressure.
  • Interventional embolization when other methods fail.
  • In some cases fracture reduction may be required to reduce bleeding.

Note: following the emergency treatment, thorough diagnostic examination may be performed to find the source of bleeding:

  • Intranasal inspection
  • Angiography with possible superselective interventional embolization.

2 General considerations top

Exposure

Management of medial orbital wall fractures has benefited from recent surgical (extension of transconjunctival incision medially) and technological developments and from technological advances such as navigation. However, it is up to the surgeon to gain the best visualization of the defect.

Exposure of medial orbital wall fractures can be very challenging. Other than techniques using transnasal endoscopic approaches, transconjunctival approaches are required for exposure of the medial orbital wall. The challenge is to use the appropriate approach providing ideal visualization of the fractures, access for insertion of material, and an optimal esthetic result. The authors recommend maintaining a safety margin of 1 cm anterior from the optic canal during dissection and reconstruction.

Note: In any midfacial or orbital fracture treatment, pay particular attention not to harm the cornea or conjunctiva chemically, mechanically, or by heat. Care should be taken to prevent injury beginning with surgical preparation (surgical scrub) and throughout the entire surgical procedure. Special corneal protectors, ointments, or temporary eyelid suture techniques should be considered to prevent corneal or conjunctival irritations.


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Visualization of fracture

Appropriate exposure of the orbit requires adequate visualization. This requires appropriate retraction of the soft tissues and lighting. Regular OR lights serve this purpose for the midorbit. The posterior orbit is better visualized using headlights or illuminated retractors.


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Special malleable orbital retractors (straight or anatomically formed) are available with metric markings providing the surgeon with additional information regarding the extent of the fracture and the depth of the orbital dissection. Specific orbital retractors have been developed to improve orbital retraction and minimize prolapse of soft tissue during insertion of implants.


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Medial wall

The uninjured medial orbital wall has a bulge towards the orbital contents to be reconstructed. This can be particularly challenging when the medial wall fracture extends posteriorly.

Note: the extent of the reconstruction required for this medial wall fracture.

3 Choice of reconstruction material top

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General considerations

The unique and complex anatomy of the orbit, unless prebent plates are used, requires significant contouring of the implants to restore the proper anatomy. The majority of cases with larger defects require reconstruction of the orbital wall to restore the shape of the orbit. The reason for this is that the bony walls are comminuted and/or bone fragments are missing. Therefore, one is reconstructing missing bone rather than reducing bone fragments. This can be accomplished using various materials.
There is hardly any anatomic region in the human body that is so controversial in terms of appropriate material used for fracture repair:

  • Nonresorbable versus resorbable
  • Autogenous/allogenous/xenogenous versus alloplastic material
  • Non-prebent versus preformed (anatomical) plates
  • Standard versus custom-made plates
  • Nonporous versus porous material
  • Noncoated versus coated plates

Many surgeons recommend using materials that allow bending to an anatomical shape, that are radiopaque (to allow for intra- or postoperative radiologic confirmation of placement), and stable over time.

Reconstruction of the dislocated orbital walls is demanding. Secondary changes to this contour are undesirable. This is why critical consideration of the use of resorbable materials is necessary.

There are different preferences of implant material depending on regional differences, variations in schools of teaching, and socio-economic factors. There is a paucity of evidence to support the ideal choice for an orbital implant. Modern imaging analysis offers a unique chance to quantitatively asses the surgical result and stability over the time. This can provide valuable information for future recommendation.


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Titanium meshes

Advantages:

  • Availability
  • Stability
  • Contouring (eased by the artificial sterile skull)
  • Adequate in large three-wall fractures (the pre-bent plate is limited to medial wall and orbital wall fractures only).
  • Radiopacity
  • Spaces within the mesh to allow dissipation of fluids
  • No donor site needed
  • Tissue incorporation may occur

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Disadvantages:

  • Costs
  • Possible sharp edges if not properly trimmed

Note: We do not have long term experience in a large series regarding the use of metallic mesh in young children. In several pediatric cases starting after the age of four it proved to be safe.

Note: The extensive use of mesh for orbital reconstruction in traumatized orbits has been shown to be safe, with few problems due to infections and no problems with secondary displacement due to additional trauma, provided proper handling, contouring, and fixation of the mesh.


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Bone graft

Illustration showing individual calvarial bone graft.

Advantages:

  • Low material costs
  • Smooth surface
  • Variability in thickness
  • Radiopacity
  • Maximal biocompatibility
  • Periorbita readily dissects off of the bone in secondary reconstructions

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Disadvantages:

  • Additional donor site needed (providing an additional surgical site for time of harvest, pain, scar, and additional possible surgical complications)
  • Possible contour and dimensional changes due to remodeling
  • Difficult to shape according to patients anatomy
  • Less drainage from the orbit than with titanium mesh

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Porous polyethylene sheets (PPE)

Advantages:

  • Availability
  • Contouring (eased by the artificial sterile skull)
  • Smooth edges
  • Allows tissue ingrowth

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Disadvantages:

  • Not radiopaque (not visible on postoperative images)
  • Lack of rigidity when a very thin wafer of PPE is used. When a more thick rigid wafer is used there is a risk of causing a dystopia.
  • Less drainage from the orbit than titanium mesh

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Composite of porous polyethylene and titanium mesh

By combining titanium mesh with porous polyethylene the material becomes radiopaque, and more rigid than porous polyethylene of a similar thickness. Some surgeons also believe that there is less risk of having retained sharp barbs, which can lead to an entrapment of soft tissues during placement.

Advantages:

  • Availability
  • Stability
  • Contouring (eased by the artificial sterile skull)
  • Adequate in large three-wall fractures (the pre-bent plate is limited to medial wall and orbital wall fractures only).
  • Radiopacity
  • No donor site needed
  • Tissue incorporation may occur

Disadvantages:

  • Less drainage from the orbit than titanium mesh

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Resorbable materials

Thermoplastic and non-thermoplastic materials

Advantages:

  • Availability
  • Handling/Contourability (only for thermoplastics)
  • Smooth surface and smooth edges

Disadvantages:

  • No radiopacity
  • Degradation of material with possible contour loss
  • Sterile infection / inflammatory response
  • Difficult to shape according to patients anatomy (only for non-thermoplastics)
  • Less drainage from the orbit than uncovered titanium mesh (in case when nonperforated material is used)

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Illustration showing a non-thermoplastic PDS sheet.


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Preformed orbital implant

Advantages:

  • Radiopacity
  • Smooth surface
  • Minimal or no contouring necessary

Disadvantages:

  • Cost

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Multiplanar and 3-D view showing a preformed mesh plate placed prior to surgery into patient CT dataset.


Implant fixation

Fixation of orbital reconstruction material varies with the type and nature of the fracture.

Fixation of most materials in the orbital floor is achieved by the use of one or more screws. The diameter depends on anatomical requirements but will normally vary between 1.0 1.3, or 1.5 mm. Alternatively Matrix Midface screws can be used.

4 Surgical exposure top

Periorbital dissection

After initial exposure, periorbital dissection is performed.


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Retraction

Adequate exposure (via a transcaruncular, transconjunctival approach with or without extension onto the orbital floor) and illumination (headlights, illuminated retractors) of the fractured area is imperative prior to fixation.

Adequate hemostasis has to be achieved.

Appropriate retraction of the intraorbital soft tissues has to be performed.


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A foil (or sheet of other material) may help with a retractor to avoid prolapse of soft tissues, to improve visualization, and prevent entrapment of soft tissues during implant placement.

The illustration shows the insertion of this foil below the retractor.


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The retractor is then removed, placed under the foil, and the orbital soft tissues are properly retracted.

Note: Do not forget to remove the foil following implant placement.


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This illustration shows the foil greater than the size of the retractor.


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Helpful devices

Many different devices have been used to facilitate retraction of the orbital contents, including malleable retractors, spoons, and special orbital retractors designed for the globe (as illustrated).

5 Reconstruction top

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Measurement of defect size and determination of implant size

A careful assessment of the defect size should be performed preoperatively with the CT scan.

It is debated whether or not to extend the anterior part of the mesh over the infraorbital rim. Regardless of which fixation is placed over or posterior to the orbital rim, the overlying soft tissues must not be compromised in terms of form and function. Problems with the lower eyelid can be minimized by optimizing the fit, size, and thickness of the implant.


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Example of reconstruction with titanium mesh

The mesh is cut, …


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… all sharp edges of the plate are trimmed off to protect the soft tissues (note the shape of the fan has only a minimum number of screw holes), …


… and contoured to achieve the required shape, and accommodate key anatomical structures (nasolacrimal duct, infraorbital nerve, and optic nerve)

It is advisable not to extend the implant further posterior than 1 cm anterior to the optic canal entrance (if the posterior support to the orbit can be reached).


A sterile artificial skull allows proper anatomical contouring of the implant.
Note:

  1. The necessity for screw fixation varies with the type of material used and nature of the fracture.
  2. It is important to use a plate large enough to span the entire defect.

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Regardless of the implant chosen, the insertion process must prevent deformation of the mesh. Under adequate retraction of the intraorbital soft tissues the implant has to be positioned so that proper and stable reconstruction of the orbital walls results. Care has to be taken that neither orbital fat nor muscles are entrapped. During the insertion process, the mesh may require rotation in order to be properly positioned.


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Navigation

Additionally, navigation may serve for intraoperative control of implant or fragment position. Modern 3-D C-arm technology will further improve intraoperative quality control of implant positioning. Endoscopic modalities may be helpful in confirming proper implant placement.

6 Fixation top

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Mesh fixation

If fixation is required, one screw will suffice in most cases. The screw size has to match the chosen mesh type.


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Alternatively, the mesh can extend over the orbital rim and a screw can be placed on the anterior face of the maxilla.


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Forced duction test

After the insertion of any implant material, it is imperative to perform a forced duction test to assure that the implant has not created a decrease in ocular motility.

Click here for details on the forced duction test.

Note: Pupils should be checked; however pupillary function might be compromised by drugs or mechanical force to the orbital contents.


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Alternative: Bone graft

If bone is harvested from a donor site, eg, cranial vault (parietal area), iliac crest, mandible, rib, etc. there may be donor site morbidity.

According to the dimension of the defect the bone has to be adapted and may be fixed either with screw fixation only or with plate and screw fixation (as illustrated).

v1.0 2009-12-03