Advanced Plastic Surgical Techniques: Facial Prosthetic Considerations, Periorbital Free Flaps, Reanimation, and Corneal Sensory Restoration

Fig. 8.1
(a) Well-healed orbital exenteration defect lined with a split-thickness skin graft. (b) Orbital prosthesis fabricated with a custom methyl methacrylate ocular component integrated into a silicone orbital prosthesis, which is retained with skin adhesives. (c) Excellent foundation for an orbital prosthesis provided by graft. (d) Unfortunately most orbital prostheses are static, while the remaining lids and globe retain significant function and movement. Use of tinted and magnified lenses (e, f) may help to provide optical illusion of symmetry and function for the static orbital prosthesis. Corrective lenses also provide protection, and mask margins, of the orbital prosthesis

Although similar principles apply for defects in both children and adults, reconstruction in children is further compounded by expected growth and the need to achieve lasting symmetry. Free microvascular tissue transfer to the periorbital area can satisfy a diverse range of reconstructive needs and is necessary for stable reconstruction of most larger and complex defects. In this chapter we draw on pediatric as well as adult examples to emphasize common principles of reconstruction and rehabilitation.

Reconstructive Considerations

The optimal management of periorbital defects is best accomplished through a team approach with collaboration between the pediatric ophthalmologist, the reconstructive surgeon, the prosthodontist/prosthetist, and the patient. Appropriate planning needs to consider the following: (1) the magnitude of the defect, (2) the quality of the adjacent hard and soft tissues, (3) other tissues and materials available for reconstruction and restoration, (4) mechanisms available for achieving stability and retention for anticipated prostheses, (5) functional and aesthetic requirements, (6) emerging technologies to retain a prosthesis and restore movement and vision where possible, (7) the patient’s ability to tolerate the procedures and (8) patient and family expectations. With appropriate planning and collaboration, optimal results can be achieved and enable rehabilitated patients to lead normal lives without significant psychosocial stigma.

After comprehensive evaluation and assessment, the decision must be made to provide exclusively surgical repair, prosthetic rehabilitation, or a combination of the two modalities. Prosthetic options include ocular, orbital, and facial prostheses. The selection of treatment modalities is determined by the characteristics of the defect and the available reconstructive options and is influenced by patient age, comorbidities, and patient preference. Notable facial differences and, in particular, absence of the ocular globe can be difficult to conceal and lead to significant psychosocial distress, especially in children. Every effort should be made to optimize the aesthetics of the reconstruction, minimize visible facial scarring, and utilize an ocular prosthesis whenever possible in this population age group.

Surgical restoration of the bony and soft tissue components of the defect with autogenous tissue is always preferred as successful surgical repair can provide a stable, long-lasting reconstruction and can eliminate the inconveniences associated with a facial prosthesis. Prostheses must be removed and cleaned on a daily basis. Often the supporting tissues must be left uncovered for 6–10 hours per day to allow adequate recovery. This interval is a time of compromise and embarrassment for many. Patients may have difficulty placing the prosthesis in the proper orientation or have difficulty tolerating the chemical irritation of adhesives. Static prostheses must be remade or revised as the patient grows. The average material life of a prosthetic rehabilitation prior to material degradation ranges from to 2 to 5 years.

Prosthetic rehabilitation does have advantages for certain patients. Patients with compromised medical status or inadequate donor tissues are poor candidates for surgical intervention. Patients who have had high-dose radiotherapy to the orbit are at increased risk for tissue compromise, notably osteoradionecrosis, restricted growth, or fibrosis. Some patients who have had periorbital neoplasms resected are advised to maintain an obvious surgical defect to allow adequate visualization and monitoring of the tumor bed. Other patients may prefer to avoid additional surgical interventions altogether. Additionally, children treated with tumoricidal doses of radiotherapy to immature growth centers may also exhibit developmental retardation with resultant deformities.

The magnitude of the facial defect , including size as well as type of tissue components missing, is the next important consideration in reconstructive planning. Autologous tissue reconstruction requires an appreciation for the three-dimensional aspects of the orbital defect, and the prosthetic requirement will dictate the type of reconstruction needed [1]. A small soft tissue defect is often easier to repair, surgically or prosthetically, than a large facial defect involving multiple tissue components. For smaller defects, restoration of form and aesthetics more readily can be achieved with a well-made prosthesis or local flap repair. The casual observer may be unaware that the patient has had surgery and is using a facial prosthesis. However, unfortunately, it is still not possible to provide a prosthesis that can restore vision or undergo normal physiologic color change such as blushing or tanning.

The condition of the local tissues is another important consideration in planning periorbital reconstruction. Scarring and tissue damage from previous surgical procedures, traumatic injury, or radiation treatments can limit local flap options and necessitate free tissue transfer even for smaller defects. In addition, these same conditions can make free tissue transfer procedures more challenging, lengthy, and invasive due to lack of adequate donor vessels in close proximity to the defect. Under these adverse conditions, however, successful free tissue reconstruction can optimize outcomes by bringing well-vascularized, healthy tissues to the irradiated or scarred periorbital environment, allowing for improved healing and enabling stable prosthetic restoration when jointly planned.

Prosthetic Considerations

When the globe is absent and the child is capable of utilizing an ocular prosthesis, the goal of reconstruction should focus on creating an adequate socket to accept an ocular prosthesis. Preservation of functional eyelids and mobile orbital contents facilitates the use of an ocular prosthesis that can provide normal iris and scleral appearance and the illusion of relatively normal ocular motion.

When possible, it is best to use local tissues for eyelid and periorbital reconstruction because of their similar tissue texture and color match. When the lids are preserved, the size of the ocular prosthesis is limited by the ocular aperture. If a larger prosthesis is required to supplement soft and hard tissue deficiencies, most patients find an orbital prosthesis preferable to an excessively large ocular prosthesis. A very large ocular prosthesis may be difficult or impossible to insert between the lids. In this situation, the best option is to surgically augment the defect to allow fabrication of a reasonable size ocular prosthesis. Often local tissues are not available, or the complexity of periorbital defect and the requirements for appropriate prosthetic use exceed the limits of regional flaps, and free tissue transfer is needed.

A larger defect extending beyond the confines of the orbit is more difficult to restore. Patients who have had a full orbital exenteration often must rely on a facial prosthesis for the most aesthetic restoration. Basic requirements must be met for prosthetic success, which foremost include adequate space for placement of the prosthesis. Placement of a prosthesis on a bulky flap that projects beyond the confines of normal facial contours will attract attention and is less satisfactory than no restoration (Fig. 8.2).


Fig. 8.2
Patient with rectus myocutaneous flap reconstruction for orbitomaxillary defect

A slightly retruded prosthesis is less noticeable than one that is prominent. Magnification in corrective lenses worn over an orbital prosthesis can help to mask an over- or undercontoured prosthesis (Fig. 8.3).


Fig. 8.3
Use of corrective lenses to mask facial asymmetry. (a) Following a radical maxillectomy in continuity with an orbital exenteration and postoperative radiation therapy, a significant surgical removal of skeletal support and muscle atrophy has resulted in depression of the right side of the face. A facial prosthesis was to match the depressed facial contours. (b) Corrective lenses with additional magnification of the lens over the prosthesis provide a more desirable aesthetic result. (c) Corrective lenses with tinting of the superior half of both lenses can further mask margins and improve appearance

It is difficult to achieve acceptable aesthetics and prosthesis durability with an orbital prosthesis less than 1 cm in thickness because a thin prosthesis is likely to tear during application, removal, or cleaning.

The quality of the supporting and marginal tissues is critical to prosthetic success. As with any prosthesis, a stable and immobile base is preferred. With newer, flexible silicone materials, some movement of marginal tissues can be tolerated. It is, however, very difficult to make a prosthesis that can move with adjacent tissues. If function or facial expression causes movement of the tissues adjacent to or underneath the prosthesis, it will become dislodged or displaced. Initially this is evidenced by the margins of the prosthesis breaking away from the supporting tissue. Surgical undermining of soft tissues along the margin of the defect and placement of split-thickness skin grafts at the margin will provide an immobile base and improve the integrity of the prosthetic rehabilitation. Prosthetic rehabilitation with split-thickness skin grafts can be successful long term but can be subject to breakdown from previous radiation for tumor management (Fig. 8.4).


Fig. 8.4
(a) Split-thickness skin graft used to line an orbital defect after 1 week of healing. (b) Fully healed split-thickness skin graft used to line an orbital defect providing excellent quality keratinized immobile tissue to support an orbital prosthesis. (c) An orbital prosthesis blended in to surrounding tissues of the split-thickness skin graft. (d) The same defect, more than 5 years after prosthetic rehabilitation, developed an osteoradionecrosis which responded well to hyperbaric oxygen therapy and limited debridement, while the patient was able to continue with the same orbital prosthesis

Communications between the orbital defect and the upper aerodigestive tract should be eliminated if possible. Without bony separation of the potential air spaces, the flap will vibrate or substantially move, causing displacement of the prosthesis. Air pressure from respiration can cause movement of the flap or the prosthesis. Additionally, respiratory moisture can cause failure of the adhesive used to retain the prosthesis. If the patient has nasal reflux through the defect, the retention and hygiene maintenance of the prosthesis can be further compromised. It may be necessary to add a secondary prosthesis such as a superiorly based obturator to provide separation of the defect from the airway and minimize movement secondary to speech or respiration.

Orbital Prostheses

If the goal is to utilize an orbital prosthesis, then the reconstructive efforts should be focused on developing adequate hard and soft tissue support and retentive capability for the prosthesis. Considerations should include preservation of a bony socket with good bone stock for potential osseointegration. Soft tissue coverage of the prosthetic bearing area should be keratinized epithelium. A split-thickness skin graft lining the defect provides an excellent base for an orbital prosthesis. If an osseointegrated implant retention is to be used for the prosthesis, the underlying skin or mucosal bed should be contoured to provide a total maximum thickness of 2–3 mm. If conventional prosthetic adhesives instead of craniofacial implants are to be used for retention, the soft tissue must be thick enough to block out substantial soft tissue and bony undercuts and to withstand the load of the prosthesis and tension associated with removal of the adhesive retained prosthesis. Limited undercuts can aid in the mechanical retention of a prosthesis. Excessive undercuts often lead to trauma of the marginal tissues as the prosthesis is inserted and removed.

If a prosthetic rehabilitation of the orbit is to be retained with osseointegrated craniofacial implants , adequate bone stock and a very thin soft tissue envelope are most helpful. This may require bony osteotomies, if one is adding bone, and, if necessary, a debulking procedure or skin graft in the future. If the goal is to avoid prosthetic rehabilitation, the reconstructive plan should focus on obliterating the cavity with a well-vascularized, bulky flap providing good soft tissue fill (Fig. 8.5). If the patient’s lids are resected, it is difficult to place and contour a soft tissue flap that will recreate natural appearing eyelids to retain an ocular prosthesis. When the lids have been excised, a better cosmetic result is usually achieved with an orbital prosthesis.


Fig. 8.5
Latissimus dorsi flap for orbitomaxillary reconstruction

Ocular Prostheses

Many enucleations leave a patient with adequate soft tissues and orbital bone requiring only ocular prosthetic intervention. A custom ocular prosthesis can be fabricated to fill the enucleation defect with an excellent cosmetic result (see Chap. 41). Historically, ocular prostheses were fabricated of individually blown glass. Currently, most ocular prostheses are fabricated of methyl methacrylate polymers that are cast to fit a mold of the defect. Each prosthesis is hand colored to match the remaining eye. Methyl methacrylate ocular prostheses can also be shaped to provide support for a drooping upper eyelid (Fig. 8.6).


Fig. 8.6
Ocular prosthetics. A custom methyl methacrylate ocular prosthesis provides nonsurgical restoration of enucleation defects. (a) The prosthesis can be modified to provide support for a ptotic eyelid. The acrylic can be contoured with flanges or shelves to provide improved positioning of the lids. (b) A shelf provides support for the lower lid. (c) An acceptable aesthetic result achieved with a modified ocular prosthesis, but over the long-term surgical repair of the ptotic lid may be preferable

A well-adapted ocular prosthetic shell placed in an ocular socket overlying functional extraocular muscles can appear to track movement in concert with the remaining eye. This movement may be enhanced by integrating the prosthetic shell with a post connected to a porous ocular implant within the muscle cone, but this is usually reserved for the adult population. Any patient who has had an orbital enucleation or exenteration should be encouraged to wear protective lenses to minimize risk of injury or loss of the remaining, functional eye. The eyeglass lens for the defect side can be tinted, clouded, or opaqued to help mask the residual deformity. The lens may also be made to match any corrections required to improve normal vision in the remaining eye. Cosmesis is improved when both corrective lenses are balanced to match. The corrective lens, however, can include magnification to mask postsurgical depression of the defect or postradiation atrophy of the periorbital structures (Figs. 8.1 and 8.3).

Attempts at reconstruction of the eyelids and socket are not always successful, however. Fabrication of an ocular prosthesis may provide less desirable results than surgical preparation of a defect suitable for an orbital prosthesis (Fig. 8.7).


Fig. 8.7
(a) Severe trauma from a motorcycle accident resulting in orbital fractures with loss of the left globe and eyelid structures. (b) Post additional reconstruction with an ocular prosthetic. An orbital prosthesis may have provided a much better aesthetic result minimizing the number of surgical procedures to reach this endpoint

Orbital prosthetic replacements should not be attached to or retained with eyeglasses. Patients do not want to remove their facial prostheses every time they have to clean or remove their eyeglasses. As eyewear slips during normal activities, it is very embarrassing to have the prosthesis become dislodged. Adhesive or implant retention eliminates the need to retain a prosthesis by attaching it to eyeglasses.

Socket expansion is sometimes necessary to provide an adequate space for an ocular prosthesis. Expansion has long been used as a treatment in patients with periorbital defects. For young patients, custom methyl methacrylate conformers of increasing size can be placed as the child grows. This will help to preserve the contours of the ocular defect to retain a prosthesis. Use of ocular conformers of increasing size can also aid in stimulating normal growth of the periorbital bone and soft tissues and minimize the need for surgical expansion of the periorbital area. On occasion, however, multiple osteotomies with the use of either free bone grafts or vascularized free flaps are necessary [2, 3] (see Chap. 39). Numerous free flaps have been advocated to restore or replace destroyed periorbital tissues and are described in more detail within this chapter [419].

The most severe deformity usually exists in patients who have undergone enucleation at an early age, followed by radiation therapy for retinoblastoma or other malignant orbital tumors (Fig. 8.8).


Fig. 8.8
Bilateral enucleations followed by radiation for retinoblastomas. Radiation therapy to the orbit at an early age produced severe deformities of the orbits

These patients often have considerable contraction of the socket and hypoplasia of the orbital bone and periorbital soft tissues. For these patients, the conventional skin graft or mucosal graft is not effective because of the poor vascularity of the region. Furthermore, the depression is too severe to fill in with local skin flaps alone. Free soft tissue transfer will improve the vascular supply to this region and avoid postoperative contracture. When prosthetic rehabilitation is anticipated, an immobile base of tissue must be prepared that is suitable to withstand skin adhesives or allow placement of osseointegrated implants.

Osseointegrated craniofacial implants closely resemble those used intraorally to support dental restorations [20]. The implant fixtures are fabricated of medical-grade titanium and usually have a threaded, screw-type design. There are two major differences between intraoral and craniofacial implants. Craniofacial implants are short, usually 3–5 mm in length. They also have a flange about the top of the fixture to limit the depth of implant placement and maximize contact of the fixture to the bone surface (Fig. 8.9).


Fig. 8.9
Titanium craniofacial implant placed with flange countersunk in cortical bone to resist displacement

Each implant is placed in a receptor hole that has been drilled and tapped at very low speeds with copious irrigation to minimize heating and injury of the bone. Fixtures are not loaded and are usually kept submerged below the epithelium for 4–6 months to allow maximal healing of the surrounding bone against the implant.

After an appropriate healing period, the implant fixtures are exposed, and abutment connections are placed (Fig. 8.10). A cast gold alloy or titanium suprastructure is fabricated to connect the fixtures and incorporate magnets, snaps, or clips for retention of the prosthesis (Fig. 8.11). The patient must maintain meticulous daily hygiene about the transcutaneous implant connections to prevent tissue irritation and inflammation.


Fig. 8.10
Craniofacial implants used to anchor facial prosthesis. (a) Craniofacial implant placed in bone with flange flush or countersunk in cortical bone. The fixture on the right demonstrates a sealing screw, which is left in place for the first 4–6 months, while the implant is buried to allow osseointegration. The sealing screw prevents bone growth into the internal threads visualized on the left. (b) Implants should be strategically placed in the residual bone of the orbital rim. Specific site selection should be performed preoperatively by the surgeon and maxillofacial prosthodondist. (ce) Implant abutments have been attached to the implants to serve as transmucosal connectors of the implants to the implant bar (shown with one retentive clip in place). The abutment height should be selected to allow the top of the abutment to be immediately above the level of the epithelium. (f) The final implant bar should be above the level of the epithelium to allow proper hygiene and home care (shown with one retentive clip in place)


Fig. 8.11
Craniofacial implants placed within the orbital rim anchor a cast metal bar with magnetic keepers or configuration for retaining clips or snaps. The magnets, clips, or snaps are incorporated into the facial prosthesis to provide positive retention and eliminate the need for adhesives to retain the prosthesis. (a) Titanium craniofacial implants can be positioned in available bone of the superior and lateral orbital rim. (b) Transcutaneous connectors join the craniofacial implants to a cast metal suprastructure. (c) Three magnetic keepers are incorporated into the cast metal implant suprastructure. (d) Magnets are incorporated into the tissue surface of the facial prosthesis to provide a positive seat and retention. (e) A bar with retentive clips can be used instead of magnets. Retentive clips are demonstrated in the facial prosthesis

The orbital prosthesis is fabricated using a combination of methyl methacrylate and silicone polymers. An impression of the defect, implant suprastructure, and surrounding tissues is made and used to fabricate a reinforced gypsum cast. A prefabricated or custom-made ocular prosthesis is incorporated into a wax or clay sculpture defining the contours, extent, and texture of the final prosthesis. The prosthesis is fabricated using a “lost-wax” casting technique. Natural color is accomplished using intrinsic and extrinsic stains to complement the natural surrounding tissues.

Reconstructive Options

Prior to the advent of microsurgical techniques, a variety of regional flaps were used for periorbital reconstruction [4]. These included pedicled flaps such as the sternomastoid platysma flap, the deltopectoral flap, the temporalis flap, and pedicled vascularized cranial bone flaps (Fig. 8.12). These flaps are still useful today, but are often affected by a hostile environment such as in radiation injury or the composite tissue requirement from a severe trauma or congenital absence. Microsurgical tissue transfer techniques can offer a variety of tissues for the appropriate replacement. Furthermore, microsurgical reconstruction can provide a number of composite flaps in a single operation without the need for staging. This chapter emphasizes both the use of microsurgery in reconstructing the periorbital region in children and the surgical preparation of the facial defect for a facial prosthesis.


Fig. 8.12
Orbital evisceration . (a) Young boy after orbital enucleation from a retinoblastoma. Orbital defect due to skin graft breakdown following irradiation. (b) Lateral view. (c) Temporalis muscle flap through zigzag coronal incision. (d) Note the use of the anterior half of the muscle to fill the orbital defect. The posterior temporalis is rotated anteriorly to fill the donor-site defect. (e) Muscle transposed into orbital defect can provide a vascular bed for a skin graft or even a dermis fat graft for additional volume

Most studies reporting on free tissue reconstruction of periorbital defects involve adults; fewer have specifically addressed techniques and results in the pediatric population. Pediatric microsurgery in general, however, is now routinely performed at most large pediatric institutions. Several studies have reported successful outcomes, demonstrating that vessel size, even in young children, is sufficient for successful free tissue transfer [2126] (Fig. 8.13).
Dec 19, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Advanced Plastic Surgical Techniques: Facial Prosthetic Considerations, Periorbital Free Flaps, Reanimation, and Corneal Sensory Restoration

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