Endoscopic orbital surgery

Updated August 2024

Christopher Lo, MD and Daniel Rootman, MD, MS

There has been a trend towards improving visualization during minimally invasive and keyhole approaches with endoscopic instrumentation and techniques. This broad overview covers some of the possible applications of endoscopic-assisted visualization in orbital surgery.

Indications and contraindications for endoscopic orbital surgery

Indications

Medial orbit

Well circumscribed tumor medial to the optic nerve (excision)
Poorly define orbital mass medial to optic nerve (biopsy)
Subperiosteal: abscess, hematoma, seroma
Optic canal decompression or other pathology

Sino-orbital

Mass primarily in the sinus extending into the orbit

Cranio-sino-orbital (TONES)
- Mass extending through skull base into sinus and orbital space
- Mass within cavernous sinus or Meckel’s cave
Frontal sinus
- Mucocele with bone erosion and orbital involvement for drainage (associated with frontal sinus outflow surgery)
- Frontal sinus mass erosion through the orbital roof
- Transorbital access to frontal sinus mass (ipsilateral or contralateral)
Orbital trauma
- Endoscopic assisted medial wall reduction
- Endoscopic assisted floor reduction (endonasal or Caldwell luc approach)
Trans-orbital endoscopic surgery
- Transmaxillary pterygopalatine surgery
- Transorbital intracranial surgery of anterior cranial fossa (roof approach)
- Transorbital intracranial surgery of middle cranial fossa (lateral with or without marginotomy approach)

Contraindications

Relative

Medical risks for anesthesia
Excessive bleeding risk
- Bleeding diathesis
- Anticoagulation
Presence of systemic infection

Intraorbital anatomic position

Lateral to optic nerve for endonasal approaches
Peribulbar anterior orbit

Absolute

Inability to tolerate risk of surgery or anesthesia

Pre-procedure evaluation

Complete medical/ophthalmic history with special attention to:

Known malignancy
Prior ocular/orbital/sinus surgery or trauma
Medications and anticoagulation
Risk factors for anesthesia complications

Clinical examination

Visual acuity
Exophthalmometry
Globe position
Extraocular motility
Optic nerve function

Afferent pupillary defect
Color vision
Visual field
Optic disc appearance

Palpable masses, lymphadenopathy
Inflammatory signs
Cranial Nerve Function
Endoscopic evaluation of septal position, nasal mucosa and anatomic variants

Preoperative Assessment

Orbital imaging

Computed tomography (CT) scan
Magnetic resonance imaging (MRI)
Angiography/venography
Ultrasound

Anesthesia

Most orbital and endonasal procedures performed under general anesthesia due to oropharyngeal bleeding risk
Throat pack may be considered

Hemostasis

Stop anticoagulants prior to surgery if possible (according to comorbidity and medical guidelines)
Nose is packed with 15 oxymetazoline-soaked neurosurgical Cottonoid patties
Cocaine solution can be used if no contraindications

Maximum cocaine dose is 3 mg/kg

Injection of with lidocaine 2% with epinepherine 1:100,000
Patient can be positioned to 30-degree anti-Trendelenberg
Blood pressure and heart rate control via anesthesia
Suction-assisted monopolar and bipolar cautery
Hemostatic agents: Thrombin, Floseal

Equipment

Rigid endoscope

Angle of view

0-degree tip

Provides “straight on” view

30-, 45-, 70-degree tips
- Angled tips allow surgeon to see “around corners”
- Angles above 45 degree may easily lead to disorientation

Diameter of scope

2.7 to 4 mm

Larger diameter provides better image, greater illumination and increased durability

Maintenance of view

Irrigating sheaths can deliver a stream saline to clear view
Anti-fogging agent such as cetrimide or FRED (Covidien Surgical, Mansfield, Massachusetts)

Positioning

Endoscope held in nondominant hand
Scope is white balanced, view on monitor oriented and focus adjusted with the focusing ring
Monitor should face surgeon and be parallel to surgeon’s shoulders
When used in the nose, endoscope rested on superior nasal vestibule
In subperiosteal surgery, endoscope rested on orbital rim or retractor
In certain cases the endoscope may be held through the septum and held in the contralateral nare

Procedure-specific equipment

Intraoperative navigation
Fracture fixation hardware
Osteotomes/rongeurs
Drills
Ultrasonic bone aspirators

Surgical techniques

Orbital Decompression Technique (Medial and Floor):

With patient under general anesthesia, nose is packed with oxymetazoline or alternate decongestants
Lidocaine 2% with epinepherine 1:100,000 injected
Middle turbinate is in-fractured and medialized
Uncinectomy performed
Maxillary sinus osteum is exposed and enlarged in a posterior and inferior direction
An axillary flap is created at the root of the middle turbinate and the frontal recess cleared to identify the frontal ostium
Anterior ethmoid air cells entered through the inferomedial aspect of the bulla ethmoidalis using a spoon curette or a ball probe to find the natural ostium on the medial face and out-fracture the anterior wall
Ethmoidectomy of the anterior and middle air cells is performed
Posterior ethmoids are entered inferomedially at the junction of the horizontal and vertical portions of the ground lamella of the middle turbinate
Posterior ethmoidectomy performed to the anterior face of the sphenoid
Lamina papyracea is fully exposed from the fovea ethmoidalis superiorly to the maxillary sinus inferiorly and skeletonized
Remaining air cells are removed from the skull base and laminae fractured, preserving 15 mm of the anterior lamina.
Posterior extent of a standard decompression is the point at which the thin lamina gives way to the thicker bone of the lesser wing of the sphenoid overlying the annulus of Zinn at the point approximately 2 mm anterior to the anterior face of the sphenoid
The periorbita is opened, posteriorly to anteriorly, using a sickle knife
Orbital fat is extruded into the sinus cavity with a pediatric ball probe to help separate the septae
If an orbital floor decompression is required, the maxillary antrostomy can be further enlarged to remove the medial wall of the sinus
Avoid damage to the anterior margin of the ostium
The medial aspect of the orbital floor (maxillary sinus roof) can then be in-fractured downward using a spoon curette and removed with an angled Blakesly forceps
The anterior inferomedial bone strut may be preserved and bone removed posteriorly to the posterior wall of the maxillary sinus
The periorbita may then be incised and fat prolapsed into the sinus

Optic Canal Decompression:

Ethmoidectomy performed to enter the posterior ethmoids (as described above)
The lower third of the superior turbinate is resected back to the anterior face of the sphenoid and the natural ostium of the sphenoid is identified and opened inferiorly and then horizontally into the posterior ethmoids
The anterior wall of the sphenoid is opened superiorly up to the skull base so the roof of the posterior ethmoid is continuous with the roof of the sphenoid
Once sphenoid is entered, the optic canal is seen on the superior aspect of the lateral wall of the sphenoid
The prominence of the internal carotid artery is visible inferior and posterior to the canal, though anatomic variants should be reviewed on preoperative imaging
The bone of the lamina papyracea is elevated off the periorbita approximately 1 cm anterior to the sphenoid until the thicker bone of the lesser wing is encountered
This is thinned with an irrigating and suctioning diamond burr until it can be elevated medially off the annulus
A microcurrete can be used to elevate the bone off the nerve
The medial wall of the canal is generally removed for a distance of at least 8 mm from the anterior face of the sphenoid
The superior, inferior, and posterior extent of the bony decompression will vary with the underlying compressive pathology

Patient management

Examine in recovery room for possible catastrophic vision loss
Post operative instructions
- Activity restrictions
- Ice Packs
- Elevate head of bed
- Avoid nose-blowing if sinuses entered
- Monitor for signs of bleeding or infection
Medications prescribed
- Topical antibiotics
- Pain medications
- Systemic antibiotics, if indicated
- Steroids, if indicated

Preventing and managing treatment complications

Visual Loss (Severe Vision Loss 0.84%; Jacobs, Ophthalmology 2018)

Prevention

Meticulous surgical technique with understanding of the orbital anatomy
Intraoperative pupil monitoring
Avoid excessive pressure on globe or traction on nerve
Avoid orbital injections with epinephrine products
Avoid intraoperative hypotension

Management directed towards underlying etiology

Hemorrhage

Prevention

Stopping anticoagulants prior to surgery
Meticulous surgical technique
Maintaining intraoperative hemostasis with gentle pressure, cautery, hemostatic agents

Management

Evacuation of hematoma
If no visual loss and pain not severe, can observe
If vision threatened, emergent canthotomy/cantholysis

Diplopia

Prevention

Meticulous surgical technique with understanding of the orbital anatomy
Intraoperative forced ductions when indicated

Treatment

Treatment of underlying etiology
Prisms
Ocular occlusion
Strabismus consultation if non-resolving

Cerebrospinal fluid leak (1-3% orbital decompression; Limawararut, Surv Ophthalmol 2008)

Prevention

Meticulous surgical technique with understanding of the orbital anatomy

Treatment

Plugging with orbital fat or nasal mucosal graft
Antibiotics, if indicated

Historical perspective

First endoscopic orbital decompression was performed in 1990 (Kennedy).