Eyelids and Orbit




Keywords

orbit, eyelids, oculoplastic surgery, exentration, orbitectomy

 









Although they are relatively rare, tumors that involve the eyelids and orbit are a therapeutic challenge because of the complex anatomy and diversity of pathologic processes that occur in this region. A systematic approach to evaluation and management and a thorough understanding of the pathologic processes of these tumors are required to optimize outcome. Within the eyelid, benign lesions include cutaneous keratosis and papillomas, inclusion and dermoid cysts, and cysts arising from the obstruction of sebaceous and sweat glands. In addition to these lesions, benign sweat gland tumors such as syringomas, myoepitheliomas, and sebaceous adenomas can also occur in the eyelids. The most frequently seen malignant lesions of the eyelids is basal cell carcinoma, accounting for over 90% of all eyelid malignancies, followed by squamous cell carcinomas, sebaceous cell carcinoma, melanomas, Merkel cell carcinomas, and sweat gland carcinomas.


Benign processes represent the most common orbital lesions. An orbital pseudotumor typically presents with eyelid edema, conjunctival chemosis, pain, and rarely visual loss. It sometimes can be misdiagnosed as a neoplasm on the basis of both clinical examination and imaging studies ( Figs. 4.1 and 4.2 ). The most common malignant tumors involving the orbit are extensions of primary tumors from adjacent structures, including the skin, paranasal sinuses, intracranial tumors, and metastasis. Primary malignant orbital tumors represent a small proportion of cases. Despite their rarity, they comprise a wide spectrum of diseases arising from the nerves and nerve sheaths, extraocular muscles, lacrimal gland and lacrimal drainage system, orbital bones, and soft tissues, including lipomas, fibromas, hemangiomas, and their malignant counterparts. The most common primary malignant intraocular tumor is uveal melanoma in adults and retinoblastoma in children, and these can extend into the orbit. Lymphoma and metastatic tumors also can occur in the orbit and need to be included in the differential diagnosis. Clinical examples of some malignant tumors of the eyelid ( Figs. 4.3 through 4.10 ), conjunctiva ( Fig. 4.11 ), and orbit ( Figs. 4.12 through 4.14 ) are shown here.




Figure 4.1


Orbital pseudotumor. (Idiopathic orbital inflammation).



Figure 4.2


Axial computed tomography scan of the patient in Fig. 4.1 .



Figure 4.3


Basal cell carcinoma of the lateral canthus.



Figure 4.4


Locally advanced squamous carcinoma of the lower eyelid.



Figure 4.5


Advanced squamous cell carcinoma of the lower eyelid with metastasis to the cervical lymph nodes.



Figure 4.6


Melanoma of the lower eyelid.



Figure 4.7


Malignant melanoma of lateral canthus.



Figure 4.8


Hemangioma of the upper eyelid.



Figure 4.9


A , Plexiform neurofibromatosis involving the upper eyelid and forehead. B , Coronal computed tomography scan demonstrating intraorbital extension of the tumor.



Figure 4.10


In situ squamous cell carcinoma in Bowen’s disease of the lower eyelid.



Figure 4.11


Squamous cell carcinoma of the conjunctiva.



Figure 4.12


Neuroblastoma of the orbit.



Figure 4.13


Malignant fibrous histiocytoma of the orbit.



Figure 4.14


Chondrosarcoma of the orbit.




Evaluation


Evaluation of eyelid and orbital tumors centers on an adequate history and physical examination. Orbital neoplasms may cause changes in appearance (such as lid retraction, entropion, ectropion, ptosis, proptosis, or a change in the position of the globe) or function (e.g., diplopia, blurry vision, or epiphora). Examination should focus on assessment of the position of the lid and globe, as well as their function. Functional examinations should include assessment of the opening and closing of the lid, extraocular movement, globe position, pupillary function, vision, and visual fields. Additional specialized ophthalmic examination may be used to look for change in intraocular pressure (tonometry); the anterior chamber or iris (slit lamp examinations); and the vitreous, retina, or optic disc (funduscopic examinations). The lacrimal system also may be examined to assess for obstruction or involvement of the nasolacrimal duct. In addition, assessment of ocular tumors should include a thorough evaluation of the sinonasal cavity, given the predilection of these tumors for orbital extension.


Radiographic imaging is essential to assess the extent of the tumor within the orbit and extension into the paranasal sinuses, cranial cavity, and infratemporal fossa. A computed tomography (CT) scan is preferred for assessment of bone involvement, whereas magnetic resonance imaging (MRI) is more accurate for defining soft tissue disease and perineural extension. Accurate assessment of invasion of the extraocular muscles, lacrimal gland, or lacrimal drainage system is crucial for surgical treatment planning. The orbital periosteum is a strong barrier to tumor infiltration, and its involvement as demonstrated by imaging studies is an important factor in planning reconstructive surgery to support the globe ( Figs. 4.15 through 4.19 ). A positron emission tomography scan often can demonstrate a clinically occult metastatic tumor in the orbit.




Figure 4.15


Contrast-enhanced computed tomography scan of a patient with a right-sided orbital pseudotumor.



Figure 4.16


Contrast-enhanced computed tomography scan of a patient with a liposarcoma of the right orbit.



Figure 4.17


Magnetic resonance imaging scan of a patient with a liposarcoma of the right orbit. A , Coronal view. B , Axial view.



Figure 4.18


Computed tomography scan of a patient with a leiomyosarcoma of the left orbit.



Figure 4.19


A , Computed tomography scan of a patient with a chondrosarcoma of the right orbit. B , Magnetic resonance imaging scan of the same patient showing tumor in orbit.




Benign Neoplasms


The vast majority of eyelid and orbital lesions (>80%) are inflammatory or benign neoplasms, and identifying the ones that might be malignant often poses a challenge for head and neck surgeons. Familiarity with common benign conditions that can mimic malignancies facilitates identification of malignant processes. In the eyelids, benign conditions such as inflammatory lesions (chalazia), seborrheic keratosis, pilomatrixoma, papillomas, and epidermoid inclusion cysts usually can be differentiated from malignancies by their clinical presentation. Many of these conditions require conservative surgical excision, which can be performed transcutaneously or transconjunctivally, depending on the location of the lesion.


Orbital lesions present a more complex diagnostic conundrum. Because the orbit is a confined space, different lesions in the orbit have similar presentations, including proptosis, chemosis, diplopia, and blurry vision. Imaging sometimes helps differentiate benign from malignant conditions. Idiopathic orbital inflammation, also known as orbital pseudotumors, include a broad category of nonspecific idiopathic inflammatory lesions in the orbit. These tumors can have a diverse clinical presentation, and their diagnosis is based on a combination of clinical, radiologic, and histopathologic findings after careful exclusion of specific systemic and local diseases. True benign neoplasms, including neurogenic tumors and hemangiomas, commonly arise from the lacrimal glands, adnexal structures, and soft tissues of the orbit. The management of these lesions is dictated by size, location, and symptoms.




Malignant Neoplasms


Cutaneous Malignancies


Basal cell carcinomas (BCC) represent the most common eyelid malignancy, accounting for 90% to 95% of all cases, followed by squamous cell carcinomas (5%–10%) and other malignancies (e.g., sebaceous cell carcinoma, Merkel cell carcinoma, and melanomas). Local progression of these cancers may extend to involve the orbit or globe by direct extension or perineural invasion. Squamous cell carcinomas have a higher risk of orbital invasion compared with BCC. Mohs micrographic surgery is effective in controlling small basal cell carcinoma and superficial squamous cell carcinoma of the eyelids, with local control rates above 95%. Lesions at the medial canthus are often excised incompletely, leading to a high risk for local recurrence. Local recurrence is also more common in squamous cell carcinoma than in basal cell carcinoma, and it occurs in up to a third of patients. Metastasis to the regional lymph nodes from basal cell carcinoma occurs very rarely unless the tumor is large or has recurred multiple times. Squamous cell carcinomas, deeply invasive tumors, and those with perineural invasion also have a higher propensity of spread to the regional lymph nodes. Local recurrence is as high as 30% in sebaceous gland carcinoma of the eyelids due to late diagnosis and skip lesions. As with squamous cell carcinoma, these tumors need assessment of regional lymph nodes and consideration for sentinel lymph node biopsy.


Melanoma of the eyelids is relatively rare compared with basal cell and squamous cell carcinoma. The pathogenesis of cutaneous malignant melanoma of the eyelids involve melanocytes in blue-eyed, fair-skinned persons with a history of sun exposure. Surgical management of melanoma requires wide margin of excision and paraffin confirmation of margins, as frozen section is inaccurate in up to 30% of cases. Outcomes depend on histologic features of Breslow thickness, ulceration, mitotic figures, and perineural or lymphovascular invasion. Lesions that are determined to be a Clark’s level IV or greater, Breslow thickness 1.5 mm or more, or greater than AJCC stage T2b are associated with a worse prognosis.


Glandular Malignancies


Given the relative abundance of sebaceous glands, it is not surprising that the eyelid is a common site for the development of sebaceous gland carcinomas. These tumors arise from meibomian glands in the tarsus, glands of Zeis in the eyelids, and secretory glands in the caruncle. They can have a varied presentation and often are misdiagnosed, most commonly as a chalazion. Sebaceous gland carcinomas are aggressive neoplasms with a high propensity for pagetoid spread and multifocal involvement with skip areas, making their management quite difficult. Conjunctival involvement is common (in up to 80% of cases) and can be associated with unilateral blepharoconjunctivitis. Lymphatic spread can occur in up to 30% of advanced cases. Local progression can extend onto the bulbar conjunctiva, requiring exenteration of the globe.


Lacrimal gland neoplasms account for 2% to 5% of all orbital tumors. These tumors are equally divided between benign and malignant neoplasms and epithelial and lymphoproliferative lesions. These neoplasms usually present with fullness of the lateral upper eyelid and proptosis and often are palpable. Typically, these symptoms have a limited effect on extraocular movement until the lesion becomes advanced. The most common benign epithelial neoplasms of the lacrimal gland are pleomorphic adenomas. They are similar to salivary tumors in that they can have a heterogeneous radiographic appearance, including the presence of cystic spaces. Adenoid cystic carcinoma is the most common epithelial lacrimal gland cancer, accounting for 30% to 40% of cases, followed by carcinoma ex-pleomorphic adenoma, adenocarcinoma, and mucoepidermoid carcinoma. In general, the behavior of these tumors mimics that seen for corresponding salivary gland cancers. For example, adenoid cystic carcinomas have a high propensity for perineural invasion and metastasis.


Intraocular Tumors


The most common primary malignant intraocular neoplasm in adults is uveal melanoma. The highest concentration of melanocytes is in the uveal tract (i.e., the iris, ciliary body, and choroid), which is by far the most common site of origin for primary ocular melanomas. Uveal melanomas may originate from preexisting pigmented lesions, including choroidal nevi and melanosis oculi (nevus of Ota). It has been predicted that 3% of uveal melanoma patients have germline mutations in BRCA -associated protein-1 (BAP1), which comprise a cancer hereditary syndrome that includes mesothelioma, renal cell cancer, and gastric cancer, among others. The choroid is the site of origin for approximately 80% of all uveal tract melanomas, with females typically diagnosed on routine examination and a diagnosis in males being prompted by visual symptoms. These tumors are pigmented, extend into the vitreous cavity, and may show a propensity for growth along nerves, although it can also extend into the sclera and potentially into the orbit. The diagnosis can be made by ophthalmoscopy, and the extent of the tumor can be defined by imaging studies (i.e., ultrasound, CT, and MRI).


Primary intraocular uveal melanomas have a divergent clinical course compared with cutaneous melanomas. These tumors typically spread hematogenously, primarily to the liver. Management of these tumors has been a subject of considerable debate. Two large-scale prospective randomized trials (the Collaborative Ocular Melanoma Study) have compared treatment options for small, medium, and large melanomas. The trial including large choroidal melanomas showed that the addition of preoperative radiation therapy did not improve patient outcome. For medium-sized choroidal melanomas, it was demonstrated that metastatic rates were comparable for I 125 brachytherapy and enucleation, thereby offering an eye-preserving alternative in management. In general, smaller choroidal melanomas are typically observed and treated with plaque brachytherapy if there are signs of growth. Only 2.1% to 2.4% of uveal melanoma patients have radiographic or clinical evidence of distant disease at the time of treatment; however, they carry a significant lifetime risk of systemic disease recurrence. Overall survival ranges from more than 85% for smaller tumors to 70% to 85% for medium-sized tumors and less than 50% for larger tumors, even with aggressive treatment.


Retinoblastoma is the most common primary intraocular malignancy in children, with approximately 5000 cases occurring annually worldwide. Up to 80% of cases of retinoblastoma are diagnosed before the age of 3 years, with 20% to 30% being bilateral. Cone photoreceptors in the retina are thought to be the origin of retinoblastomas. Retinoblastomas typically involve the retina and vitreous, leading to the common presentation of white pupil (leukocoria or loss of red reflex) and strabismus (due to the loss of central vision). Funduscopically, these tumors appear as white to tan lesions and may detach the retina and can be associated with dislodged tumor into the subretinal space or vitreous (“seeds”).


The study of familial retinoblastoma has provided valuable insight into cancer pathogenesis. The landmark “two-hit” model proposed by Knudsen suggests that two genetic events are required for the development of retinoblastoma. In the inherited form of the disease one hit (mutation in the RB1 gene) is present in all cells (germline), and a mutation in the second copy of the RB1 gene is acquired in retinal cells (somatic), leading to their malignant transformation. In contrast, in cases of sporadic retinoblastoma, both hits must occur in a single cell for retinoblastoma to develop. It is for this reason that retinoblastoma develops at a younger age in patients with the inherited form of the disease, with a higher frequency of multifocal and bilateral retinal involvement. The RB1 gene was cloned from children with familial retinoblastoma carrying a deletion at 13q14.2. The Children’s Oncology Group version of the International Classification of Retinoblastoma groups eyes into the following categories: A (<3 mm); B (>3 mm or macular or juxtapapillary location or subretinal fluid); C (presence of localized subretinal and/or vitreous seeds less than 6 mm from the tumor); D (presence of diffuse subretinal and/or vitreous seeds greater than 6 mm from the tumor); or E (no visual potential of the globe or the presence of any of the following: tumor in the anterior segment, tumor in or on the ciliary body, neovascular glaucoma, vitreous hemorrhage obscuring the tumor or significant hyphema, phthisical or prephthisical eye, orbital cellulitis-like presentation). The use of systemic chemotherapy has largely been replaced by ophthalmic artery chemosurgery (intraophthalmic arterial chemotherapy), which has the benefit of delivering a high, localized dose to the eye while reducing the complications associated with systemic exposure. Focal treatment including laser and cryotherapy can be used as primary or adjunctive treatments. Familial retinoblastomas often are discovered early. In contrast, most sporadic retinoblastomas (>75%) appear with advanced disease (group E) and often require extensive local treatment or enucleation. In some parts of the world, particularly Asia and Africa, retinoblastoma presents late with extraocular disease extending into the orbit, posing a particular treatment challenge.


Orbital Tumors


Rhabdomyosarcomas are the second most common primary intraorbital tumors in children, typically presenting before the age of 15 years. More than 95% of orbital rhabdomyosarcomas are of the embryonal type (especially the botryoid variant). These tumors manifest as rapidly growing retrobulbar masses that can cause effects on the ocular appearance and function by pressure or direct invasion. The presence of two pathognomonic translocations (t(2;13)(q35;q14) or t(1;13)(p36;q14)), resulting in the formation of oncogenic fusion proteins PAX3-FOXO1 (FKHR) and PAX7-FOXO1 (FKHR), respectively, are present in 80% to 85% of cases of embryonal rhabdomyosarcomas and can be identified by molecular-cytologic analyses. In the past, the outcome of patients with rhabdomyosarcoma was quite poor despite aggressive treatment. The findings from four consecutive Intergroup Rhabdomyosarcoma Study Group (IRSG) cooperative trials have significantly enhanced outcome, especially for patients with locoregionally advanced disease. These trials have helped define a risk-adapted treatment strategy based on the histologic subtype, primary site, extent of disease (International Society of Pediatric Oncology [SIOP] stage, International Union Against Cancer [UICC] stage, or IRSG stage), and extent of resection. All patients with rhabdomyosarcoma require chemotherapy, and surgical excision of the primary tumor is recommended whenever possible if it does not cause major functional or cosmetic deficits. When complete excision of the tumor is not possible, adjuvant radiotherapy is recommended, with the dose modified on the basis of chemotherapeutic treatment response. A 5-year survival rate of more than 70% has been achieved in recent trials for patients with localized rhabdomyosarcoma. However, the outcome for patients with metastatic disease remains poor.


Other tumors of the orbit include those arising from soft tissues and bone such as liposarcomas, malignant schwannomas, hemangiopericytomas, chondrosarcomas, and osteosarcomas. However, these tumors are rare, and the general principles of management are the same as those for such tumors that appear elsewhere in the body.


Other Tumors Invading the Orbit


Invasion of the orbit by local extension from malignancies of the paranasal sinuses, skin, and nasopharynx form the most common malignancies invading the orbit. These tumors include diverse histopathologic entities such as squamous cell carcinomas, minor salivary gland carcinomas, sinonasal undifferentiated tumors, esthesioneuroblastomas, sarcomas, and lymphomas. Management of the orbit in these cases depends on the overall stage of the tumor, the extent of orbital invasion, and available treatment alternatives.




Treatment


Radiation Therapy


As with other anatomic sites, the treatment of eyelid and orbital neoplasms is dictated by tumor type, location, extent, and patient factors. Although surgery is the mainstay for most primary eyelid malignancies, radiation may be used in select cases. Because radiation in this area can incur a small risk of ocular surface disturbance and potentially corneal ulceration, excision is preferred for amenable tumors. To minimize injury to the cornea, lens, and lacrimal gland, a gold-plated lead eye shield generally is used. However, tungsten eye shields provide better protection from electrons than do lead shields and are preferred. Radiation with a treatment dose of 60 Gy offers excellent local control in more than 90% of patients with cutaneous malignancies of the eyelids. As the size of the lesion increases, the anticipated disfigurement of surgery versus a lower local control rate by radiation should be weighed when deciding on a treatment modality. Larger lesions (>4 cm) are best treated with surgery, sometimes followed by postoperative radiation.


The use of radiation in the periorbital and orbital regions requires special considerations because of the high radiosensitivity of structures in the anterior and posterior chambers of the globe. Radiation planning for orbital tumors always should attempt to exclude the cornea, lens, retina, and pituitary gland. Intensity-modulated radiation therapy or a proton beam plan can help exclude extraorbital normal structures while maintaining therapeutic efficacy.


Both brachytherapy and charged-particle radiation with helium ions or protons have been used effectively to treat uveal melanomas. Brachytherapy delivers a tumoricidal dose of 70 to 100 Gy to the tumor apex. A margin to include the thickness of the sclera (~1 mm) along with an additional 1 mm of tumor thickness is planned. A 2-mm margin surrounding the perimeter of the tumor also is included in the treatment field. The optimal dose rate has not been clearly defined; most treatment is delivered during a period of between 4 and 7 days. More recent experience suggests that the optimal minimal tumor dose rate is likely between 0.7 and 1 Gy per hour using episcleral plaques. The 5- and 10-year local recurrence rates are 11.5% and 15.8%. The efficacy of plaque brachytherapy versus proton beam has not been directly compared, but they are believed to be relatively equal in their efficacy. However, proton beam is superior at controlling peripapillary lesions, although it may result in higher anterior segment toxicity, which is particularly pertinent to ciliary body and anteriorly located tumors.


Surgical Treatment


Surgical treatment planning for excision of malignant lesions of the eyelids must include an appropriate plan for reconstruction of the surgical defect. Most lesions of the upper or lower eyelid can be repaired with use of local tissues. However, more advanced lesions require complex reconstructive procedures. The important issues in reconstructive surgery of the eyelids include prevention of exposure keratopathy resulting from the inability to close the eyelids (lagophthalmos); inadequate drainage of the lacrimal secretions, leading to epiphora; eversion or exposure of the conjunctiva; and impairment of peripheral visual fields because of excessive closure of the palpebral fissure. For more complex reconstructions, the reader is advised to consult more detailed textbooks of oculoplastic surgery. Complex reconstructive procedures are best handled by adequately trained and experienced oculoplastic surgeons.


Surgical Anatomy


The eyelids are a complex set of paired anatomic structures that protect the eye and facilitate continuous distribution of the tear film over the cornea. Because the skin of the eyelid is extremely thin and devoid of subcutaneous fat, surgical dissection between the skin and the orbicularis oculi muscle should be performed very carefully. The inner surface of the eyelid is covered by conjunctiva that is thin, transparent, nonkeratinized stratified epithelium. In between the tarsal plate and the orbicularis oculi muscle are the hair follicles of the eyelashes. The meibomian glands are located within the tarsal plate. The superior and inferior tarsal plates are crescent-shaped condensation of fibrous tissue that provides structural integrity to the eyelids. The tarsal plates also are attached to the medial and lateral canthal ligaments, which allow the eyelids to follow the curvature of the globe. The deepest fibers of the levator aponeurosis insert into the anterior surface of the tarsal plate and the smoother muscle of the Mueller’s muscle attach to the superior edge of the tarsus. The levator muscle elevates the eyelid under voluntary control from the superior branch of cranial nerve III while Mueller’s muscle is under sympathetic control. Most of the movement during closure of the eyelids, from contraction of the orbicularis muscle, is performed by the upper eyelid, with the lower eyelid being relatively less mobile. The posterior surface of the tarsal plates is tightly lined by conjunctiva that is continuous with the eyelid margin at the mucocutaneous junction and the fornix onto the anterior surface of the globe. The ducts of the modified sebaceous glands (meibomian glands) open on the posterior lid margin between the mucocutaneous junction and the gray line.


The rich vascular network of the eyelids arises from both the external carotid arteries (facial, superficial temporal, and infraorbital branches) and internal carotid arteries (ophthalmic artery). These arteries anastomose to form the medial and lateral palpebral arteries, which in turn form the marginal and peripheral arcades that supply the pretarsal eyelids. The small veins of the eyelids drain superficially to the facial venous system or deeply into the ophthalmic veins in the orbit. The superior and inferior ophthalmic veins of the orbit pass through the superior and inferior orbital fissures, respectively, to drain into the cavernous sinus. The lymphatics of the eyelids drain either to the preauricular nodes or the intraparotid lymph nodes and can be highly variable between individuals. The orbicularis oculi muscle is innervated by the facial nerve, its upper eyelid component is innervated by the frontal branch of the temporal division, and the lower eyelid component is innervated by the zygomatic branch.


The lacrimal drainage system consists of the upper and lower lacrimal puncta that open into the canaliculi, leading to the lacrimal sac, which continues in the lacrimal fossa as the nasolacrimal duct and eventually opens into the inferior meatus of the lateral wall of the nasal cavity. The lacrimal gland consists of two lobes: an orbital lobe and a palpebral lobe. The orbital lobe is located in the superolateral orbit in the lacrimal fossa within the zygomatic process of the frontal bone. The grayish color and firm consistency of the orbital lobe allow it to be distinguished from the orbital fat pad. The orbital and palpebral lobes of the lacrimal gland are contiguous posterolaterally but are separated anteriorly by the lateral horn of the levator aponeurosis. Because the secretory ducts of the orbital lobe traverse the smaller palpebral lobe before draining into the upper conjunctival fornix, the function of the orbital lobe can be affected by excision of the palpebral lobe. The lacrimal puncta are located within the medial canthus, the superior punctum more medially than the inferior punctum. The superior and inferior canaliculi form a common channel that drains into the nasolacrimal sac in 90% of patients. In the remaining 10%, the two canaliculi enter the nasolacrimal sac separately. The nasolacrimal sac is located in a bony fossa on the medial wall of the orbit and is approximately 10 to 12 mm in length. The sac continues into the nasolacrimal duct, which is approximately 12 to 18 mm in length in a posterior medial direction. The lining of the outflow system transitions from the stratified squamous epithelium of the canaliculi to the columnar epithelium of the sac and the duct. The nasolacrimal duct opens at the inferior meatus under the inferior turbinate in the nasal cavity. Its opening is covered by a mucosal flap (Hasner’s valve).


The bony orbital cavities contain the globes, lacrimal gland and sac, extraocular muscles, fat, blood vessels, and nerves. Seven cranial bones form the four bony walls of the pyramid-shaped orbit. The floor of the orbit forms the roof of the maxillary sinus and ends 1 cm anterior to the optic canal. Posteriorly, the floor is separated from the greater wing of the sphenoid by the inferior orbital fissure that connects the orbit to the pterygopalatine fossa (which contains the pterygopalatine ganglion and the internal maxillary artery) and to the infratemporal fossa anteriorly. The infraorbital nerve runs in a lateral to medial direction in the floor of the orbit; it is contained within a bony groove posteriorly and then a bony canal more anteriorly before it exits at the infraorbital foramen on the anterior surface of the maxilla. The rectangular medial orbital wall is composed from anterior to posterior by the maxilla, lacrimal, ethmoid, and sphenoid bones. The lacrimal fossa is formed by the maxillary and lacrimal bones. Most of the medial wall is thin ethmoid bone (lamina papyracea) that separates the orbit from the ethmoid sinuses, and thus this part of the orbit is vulnerable to infections and invasion by tumors that arise in the ethmoid sinuses. More posteriorly, the medial wall is formed by thicker sphenoid bone, and this sphenoethmoid junction is a useful landmark for the optic canal ring located about 3 to 4 mm posterior to it. The medial wall ends superiorly at the frontoethmoid suture, which indicates the position of the fovea ethmoidalis (roof of the ethmoid sinus) and the cribriform plate. The anterior and posterior ethmoidal foramina are located along the suture line approximately 24 mm and 36 mm from the anterior orbital rim.


The apex of the orbit transmits the optic nerve and other neurovascular structures from the cranial cavity. The optic canal is located medial to the superior orbital fissure and transmits the optic nerve, ophthalmic artery, and sympathetic fibers. The superior orbital fissure transmits the third and sixth cranial nerves, nasociliary nerve, ciliary ganglion (a condensation of nerves from nasociliary, sympathetic, and parasympathetic fibers from the inferior division of CN III) with postganglionic parasympathetic branches, middle meningeal artery, lacrimal nerve, superior ophthalmic vein, trochlear nerve, and frontal nerve.


The ophthalmic artery and its branches are the major arterial supply to the orbit. It passes through the optic canal and exits the muscle cone at the level of the posterior aspect of the globe. The posterior ethmoidal artery branch of the ophthalmic artery enters the posterior ethmoidal foramen approximately 6 mm anterior to the optic canal. The anterior ethmoidal artery enters its foramen approximately 12 mm anterior to the posterior ethmoidal foramen. The ophthalmic artery also supplies branches to the extraocular muscles and lacrimal gland. Its distal-most branches are the supraorbital artery that exits through the supraorbital foramen, the supratrochlear artery, and the dorsal nasal artery. The superior and inferior ophthalmic veins both drain into the cavernous sinus. Salient features of the anatomic structures in the orbit and the cross-sectional anatomy of the eyelids are depicted in Fig. 4.20 .




Figure 4.20


Anatomy of the orbit and eyelids.


Surgery for Eyelid Tumors


Excision of a Carcinoma of the Skin of the Upper Eyelid.


Unlike the lower eyelid, the upper eyelid has a generous amount of lax skin available, making primary closure of the surgical defect possible following excision of even a large skin cancer. However, there can be loss of symmetric lid crease with this. The patient shown in Fig. 4.21 has a superficial infiltrating squamous cell carcinoma involving the skin of the upper eyelid that extends into the eyebrow. Palpation reveals that the lesion is confined to the skin and does not infiltrate into either the underlying musculature or the tarsal plate.




Figure 4.21


A superficially infiltrating squamous cell carcinoma involving the skin of the upper eyelid and extending into the eyebrow.


Upon closure of the eyelid, the true extent of the lesion becomes evident. A significant portion of the skin of the upper eyelid is involved, with extension into the eyebrows ( Fig. 4.22 ).




Figure 4.22


This lesion involves a significant portion of the skin of the upper eyelid with extension into the eyebrow.


Surgical excision of this lesion will require sacrifice of a large portion of the skin of the upper eyelid, including some of the eyebrow. When planning surgical excision and repair, it is important to remember that the shape of the eyebrow must be retained or restored. To maintain the shape of the eyebrow, surgical excision at that site is oriented vertically, whereas excision of the skin of the upper eyelid is oriented transversely, like an inverted letter “T.”


The surgical defect following excision of the lesion is shown in Fig. 4.23 . Frozen sections must be obtained from the margins of the surgical defect to ensure adequacy of excision, and care should be taken to avoid sacrifice of undue amounts of underlying musculature. After achieving satisfactory hemostasis, the skin edges are undermined on the lateral aspects of the upper portion of the surgical defect. Closure of the upper part of the surgical defect is accomplished vertically with use of interrupted 3-0 chromic catgut sutures to restore the continuity of the eyebrow between its medial and lateral parts. The remainder of the surgical defect in the skin of the upper eyelid is closed transversely in two layers, with the completely closed wound resembling an inverted letter “T.” The postoperative appearance of the patient approximately 8 weeks after surgery is shown in Fig. 4.24 . Note that the eyebrow has been reconstructed to its normal shape and that the upper eyelid essentially has no disfigurement because closure of the skin defect is transverse. The aesthetic result of this repair is quite satisfactory.




Figure 4.23


The surgical defect following excision of the lesion.



Figure 4.24


The postoperative appearance of the patient 8 weeks after surgery.


Full-Thickness Resection and Reconstruction of the Upper Eyelid.


Full-thickness resection of any portion of the eyelid poses a significant reconstructive problem. Because the upper eyelid provides most of the lubricating function and protection to the cornea and globe, accurate reconstruction is extremely important to prevent any subsequent injury to the cornea. The patient presented in Fig. 4.25 has a pigmented basal cell carcinoma involving two-thirds of the width of the upper eyelid, the tarsal margin, and the adjacent conjunctiva. Surgical excision of the lesion will require a full-thickness through-and-through resection of that part of the upper eyelid with immediate reconstruction.




Figure 4.25


A pigmented basal cell carcinoma involving two-thirds of the width of the upper eyelid, the tarsal margin, and the adjacent conjunctiva.


The plan of surgical excision is outlined in Fig. 4.26 . A rectangular portion of the full thickness of the upper eyelid is resected. The shaded triangular areas at the two upper corners of the rectangular excision are wedges of skin that will be excised to permit advancement of the skin of the upper eyelid for reconstruction ( Fig. 4.27 ). A corneal shield is inserted to protect the cornea. Two heavy silk sutures are taken through the full thickness of the tarsal margin of the upper eyelid on the periphery of the intended site of excision; these stay sutures are held with hemostats to stabilize the eyelid during excision.




Figure 4.26


The outline of surgical excision and skin advancement on the upper eyelid.



Figure 4.27


The shaded triangular areas at the two upper corners of the rectangular excision are wedges of skin that will be excised to permit advancement of the skin of the upper eyelid for reconstruction.


One approach is shown here. Through-and-through resection of the upper eyelid along the previously outlined area of rectangular excision is completed ( Fig. 4.28 ). Note that the surgical excision is just medial to the stay sutures, which help stabilize the cut edges of the surgical defect. Complete hemostasis is obtained by ligating and/or coagulating the bleeding points during the excision. Similar silk stay sutures are applied to the tarsal margin of the lower eyelid and an incision is made through the gray line of the tarsal margin of the lower eyelid between the two stay sutures. The skin is retracted inferiorly to expose the tarsal plate ( Fig. 4.29 ). A sharp, fine knife is used to divide the tarsal plate in a coronal plane through its thickness to retain the inner aspect of the tarsal plate attached to the palpebral conjunctiva, while its outer aspect remains continuous with the remainder of the tarsal plate.




Figure 4.28


Through-and-through resection of the upper eyelid along the previously outlined area of rectangular excision is completed.



Figure 4.29


The tarsal plate of the lower eyelid is exposed through a skin incision at the gray line.


Using sharp scissors, two incisions are made in the palpebral conjunctiva with the attached split tarsal plate to match the surgical defect of the upper eyelid, and the incision is taken down to its reflection over the globe. This procedure will provide a composite conjunctival flap that contains a portion of the split tarsal plate from the lower eyelid, which is then advanced cephalad and sutured to the horizontal cut edge of the conjunctiva of the upper eyelid in the rectangular surgical defect ( Fig. 4.30 ). The conjunctival sutures are taken with 6-0 plain catgut sutures. Several interrupted sutures are applied, and the knots are kept on the undersurface of the conjunctiva and buried in the soft tissues.




Figure 4.30


The composite conjunctival flap containing a portion of the split tarsal plate from the lower eyelid is advanced cephalad and sutured to the horizontal cut edge of the conjunctiva of the upper eyelid in the rectangular surgical defect.


Once this bridged conjunctival repair is completed, skin incisions are made in the upper eyelid farther cephalad from the rectangular defect to match the previously outlined triangular areas of skin to be sacrificed, and these areas are excised ( Fig. 4.31 ). This procedure allows downward advancement of the skin flap from the upper eyelid, which is sutured to the cut edge on the skin side of the tarsal margin of the lower eyelid with use of 6-0 nylon sutures. Thus approximation of the lower edge of the upper eyelid skin flap and the skin margin of the lower eyelid is completed ( Fig. 4.32 ). The remaining skin closure is completed along the lateral aspect of the skin flap and then transversely through the region of the excised wedges of the skin. This process is the first stage of reconstruction of the upper eyelid ( Fig. 4.33 ). At the conclusion of the operation, the upper and lower eyelids are fused and remain so for 8 weeks. Skin sutures are removed in approximately 1 week. During fusion of the upper and lower eyelids, the patient is instructed to irrigate the eye and keep the area as clean as possible.




Figure 4.31


The previously marked triangular wedges of skin are excised.



Figure 4.32


Approximation of the lower edge of the upper eyelid skin flap and the skin margin of the lower eyelid is completed.



Figure 4.33


The remaining skin closure is completed along the lateral aspect of the skin flap and then transversely through the region of the excised wedges of the skin.


Six to eight weeks after the first stage of the operation, the patient is returned to the operating room, where the fused eyelids are divided under topical and local anesthesia ( Fig. 4.34 ). Two drops of a topical anesthetic are introduced into the conjunctival sac, and a local anesthetic is infiltrated along the palpebral fissure through the fused eyelids. A fine lacrimal probe is introduced from the palpebral fissure medial to the bridge of skin and is brought out through the fissure lateral to the bridge to protect the cornea during division of the fused eyelids. Sharp, curved scissors are used to divide the bridge of the fused eyelids along the line of the palpebral fissure, and full-thickness through-and-through division of the bridged reconstruction is performed to separate the reconstructed upper eyelid from the lower eyelid. Some minimal bleeding is to be expected from the cut edges of the reconstructed area but will stop with application of slight pressure.




Figure 4.34


Eight weeks after the first stage of the operation, topical and local anesthetic is administered and the patient’s fused eyelids are divided.


The postoperative appearance of the patient 1 week after division of the bridged lower eyelid flap to reconstruct the upper eyelid is shown in Fig. 4.35 . The functional and aesthetic restoration is complete, and the final postoperative result is very gratifying ( Figs. 4.36 and 4.37 ). Bridged repair of upper eyelid defects with use of a split tarsal plate and a conjunctival composite flap is a very satisfactory means of performing immediate reconstruction of sizable defects of the upper eyelid.




Figure 4.35


The postoperative appearance of the patient 1 week after division of the bridged lower eyelid flap.



Figure 4.36


Postoperative appearance of the patient 6 months after surgery.



Figure 4.37


Symmetry of both upper eyelids is restored.


This approach of transferring the lower lid tarsus to the upper lid sometimes renders the lower lid unstable. Other approaches for upper lid reconstruction include the Cutler-Beard with a free tarsal, scleral, or AlloDerm graft and Hughes flaps, which are also useful as lid sharing procedures.


Excision of a Carcinoma of the Skin of the Lower Eyelid.


Skin carcinomas involving less than two-thirds of the lower eyelid are easily managed by wide excision and closure by mobilizing skin from the lateral aspect of the cheek and the temporal region. When excision of a skin lesion of the lower eyelid is performed in a transverse axis with primary closure of the defect, ectropion often will result. Thus whenever feasible, the surgical excision should be planned in such a manner that an advancement flap from the lateral aspect can be brought in to close the surgical defect, thereby avoiding ectropion. The patient shown in Fig. 4.38 has a basal cell carcinoma involving the skin of the lower eyelid. The lesion does not reach the tarsal margin and is not infiltrating the underlying musculature or cartilage.




Figure 4.38


Basal cell carcinoma involving the skin of the lower eyelid.


The plan of surgical excision is outlined in Fig. 4.39 . The surgical defect resulting from this excision has a triangular shape. The upper transverse skin incision is extended along the lateral canthus into the temporal region, and the skin flap is elevated. The skin from the temporal region is thus advanced into the surgical defect. The apex of the flap slides into the surgical defect, permitting its closure. Adequate mobilization of the lateral skin is necessary to avoid tension on the suture line and secondary pull on the lower eyelid. This is also called a Tenzel flap.




Figure 4.39


The plan of surgical excision.


The completed closure shows skin sutures with 6-0 nylon in place ( Fig. 4.40 ). Note that the skin sutures beneath the lower eyelid are left long and their ends are taped or sutured to the skin of the cheek to avoid trauma to the cornea from the stumps of the sutures. No dressings are necessary, but bacitracin ophthalmic ointment is applied to the suture line.


Sep 29, 2019 | Posted by in HEAD AND NECK SURGERY | Comments Off on Eyelids and Orbit
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