Chapter Atlas- Endonasal Endoscopic Orbital Decompression

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ENDONASAL ENDOSCOPIC ORBITAL DECOMPRESSION

Introduction:

Today, there is a growing trend towards the use of minimally invasive techniques in surgery as

well as day-care surgery. This is a result of trying to achieve a better cosmetic outcome

combined with reducing the morbidity associated with extensive tissue dissection. Endoscopic

surgery exemplifies these attempts and has been enthusiastically adopted by general surgeons,

gynecologists and ENT surgeons. Endoscopic orbital surgery, is performed primarily via

sinonasal approaches by ENT surgeons. Endonasal endoscopic approaches are well established

for orbital decompression, orbital medial wall fracture repair and optic nervedecompression.

The widespread use of endoscopes in medicine followed the development of fiberoptic

transmission of light by van der Heel, Harold Hopkins and Narinder Kapany [(who coined the

term fiberoptics) (Prabhakaran and Selva, 2008)] . This allowed vastly superior illumination at

the surgical site, thus overcoming the main limiting factor of endoscopes until that time. The first

endoscope using fiberoptic transmission was a gastroscope built by Hirschowitz in 1958 (Gow,

1998). Rigid endoscopy became popular with the invention of rod lenses by Harold Hopkins in

1960 (Gow, 1998). They were first used in rigid cystoscopes and later in other endoscopes.

The use of endoscopes in orbital surgery was first described by Norris and Cleasby (1981). The

initial reports by Norris and Stewart (1985) detailed the use of the endoscope in obtaining biopsy

from orbital tumors and in removing foreign bodies from the orbit.

Endoscopic sinus surgery for the treatment of acute andchronic sinusitis was well established by

the first third of this century (Hajek, 1962). It was based on the commendable anatomical studies

of Zuckerkandl (1892), Onodi (1911) and Grünwald. Transnasal endoscopic sinus surgery was

introduced in the mid 1980s. The term FESSwas coined by Kennedy (1985). Endoscopic orbital

decompression wasfirst described by Kennedy(1990) and Michel (1991) in the early 1990s.

Overthe years, enhanced visualization of key anatomic landmarkssuch as the region of the orbital

apex, which is a critical area of decompression in optic neuropathy, has made endoscopic surgery

a versatile tool (Al-Mujaini et al, 2009).



Indications:

1. Orbital Abscess in the medial, supero-medial or infero-medial compartment of the orbit.

Fig. Axial view of a Contrast Enhanced CT Scan showing a left subperiosteal orbital

abscess with the characteristic peripheral „ring‟ enhancement (red arrow).

2. Orbital Cellulitis (Fig. ).

Fig. CT Scan of the Paranasal Sinuses, coronal cut showing right orbital cellulitis

secondary to fungal sinusitis.



3. Orbital Haematoma (Fig. ) in the medial, supero-medial or infero-medial compartment of

the orbit.

Fig. A clinical photograph showing an orbital haematoma affecting the right eye

following a fall resulting in proptosis.

Fig: Clinical photograph showing an orbital haematoma affecting the right eye following

trauma



4. Dysthyroid Orbitopathy / Thyroid-associated Orbitopathy.

Fig: Coronal CT scan showing bulky extraocular muscles, within the orbits, in the region

of the orbital apices

Fig: Axial MRI scan showing bulky extraocular muscles bilaterally, the classical „cola

bottle sign‟



5. Orbital Tumors occupying the medial compartment of the orbit (Fig. ).

Fig. Clinical photograph of a patient with right proptosis due to a nasal mass.

Fig. CT Scan of the Paranasal Sinuses (axial view) showing the tumour resulting in right

proptosis in the same patient as in Fig. .

6. Orbital Fractures confined to the medial wall or the floor (Fig. ).



Fig. A CT Scan (axial view) showing a fracture of the medial wall of the orbit with the

orbital contents prolapsed into the ethmoids.

7. Foreign bodies embedded in the orbit require decompression of the orbit to facilitate their

removal

Fig. A foreign body embedded in the left orbit

Fig. Endoscopic view of the foreign body prior to removal endoscopically. After

performing an ethmoidectomy, the splintered lamina papyracea was gently removed

piecemeal, following which the metallic foreign body was gently teased out.



Fig. The foreign body after endoscopic removal

8. Fractures of the medial orbital wall with muscle entrapment.

Fig. Axial CT scan of a patient with post traumatic medial orbital wall fracture, showing

left medial rectus entrapment. Note the fracture fragment embedded within the left

medial rectus muscle. The lamina papyracea had to be removed, and the fracture

fragment gently teased off the underlying muscle, which had also developed an

intramuscular haematoma.



Fig. The intraoperative endoscopic image showing the fracture fragment being teased

off the prolapsed orbital contents.

The sequelae of the proptosis that results due to the above-mentioned indications 1-5, includeexposure keratopathy, diplopia and eventually visual loss if not treated rapidly. Timely orbital

decompression decreases intra-ocular pressure and increases the effective volume of the orbit,

thus preventing these sequelae.

Anaesthetic Considerations:

This surgery is performed under general anaesthesia and there are no local considerations, unless

the general condition of the patient or any medical problem (such as thyrotoxicosis) may pose a

risk to anaesthesia.

Specific Investigations:

1. CT Scan of the Paranasal Sinuses with orbital cuts is anessential pre-requisite since it not

only helps to detect the site and extent of thelesion, but also serves as a road-map to guide

the surgeon during surgery (Fig. ).

Fig. A Contrast enhanced CT Scan(Coronal view) of the same patient as in Fig.

showing the haematoma occupying the superomedial compartment of the orbit thus,

rendering itself amenable to endoscopic evacuation.



Fig. A Contrast enhanced CT Scan (Coronal view) showing the presence of an apical

root abscess with acute maxillary and ethmoid sinusitis with cheek cellulitis on the left

side and an orbital abscess in the infero-medial compartment of the left orbit. This orbital

abscess was the complication of a dental procedure.

Fig. Coronal cut of the Contrast Enhanced CT Scan of the same patient as in Fig.



Fig. The axial cut of the Contrast enhanced CT Scan of the same patient as in Fig.

2. MR Imaging of the Orbit and the Para Nasal Sinuses is useful for detecting the accurate

site of the lesionwithin the globe (extraconal or intraconal)

Fig.MR Image (coronal view) of the same patient as in Fig. showing the globe „sinking‟

into the maxillary antrum following fracture of the orbital floor.

3. Thyroid Function Tests in patients with thyroid pathology.

4. Testing Visual acquity, Colour vision, Intra ocular pressure and retinoscopy are of great

importance to document pre-operative vision and integrity of the visual pathway.

Surgery of Orbital Decompression:

Other approaches used for orbital decompression :

In 1911 Dollinger performed a lateral walldecompression, nevertheless with minimal

extent.Naffsinger (1931) developed a superior decompression of thecontents into the anterior

cranial fossa.Consequently, Sewall (1936) described a medial walldecompression through an

external ethmoidectomyapproach. Hirsch (1950) was the pioneer to employ a Caldwell-Luc

approach to obtain result by removal of the orbitalfloor. Walsh & Ogura in 1957, extended this

approachto include a medial wall decompression. Since then,this approach is widely accepted as

the standard approachfor orbital decompression. In 1990 Kennedy describedthe first approach

using nasal endoscopes. To maximizethe degree of decompression obtained, he used a

WalshOgura approach with a lateral orbitotomy.



Steps of Endoscopic Orbital Decompression:

1. Performing an uncinectomy

2.

Performing an endoscopic spheno-ethmoidectomy

3. Exposing the lamina papyracea (a) upto the orbital apex where one encounters the hard

optic tubercle, which seperates the posterior ethmoids from the sphenoid (b) and even to

visualize the optic nerve (c)

(a)



(b)

(c)

4. Gentle removal of the thin bone of the medial orbital wall (lamina papyracea) taking care

not to injure the underlying orbital periosteum



One must be very careful to ensure that the orbital periosteum does not get injured in this

process, as it will obscure the removal of bone behind it. Even if the orbital periosteum

needs to be split, it must be done after the entire lamina has been exposed.

5. Slitting the orbital periosteum, if indicated.

Advantages:

There are several advantages of an endoscopic orbital decompression over the external

approaches:

Minimal Access Surgery

Decreased morbidity

No external scar



Easy access to the orbital apex

Improved access to the inferior and medial walls of the orbit

Simultaneous treatment of sinusitis

Contraindication:

The endonasal endoscopic route for orbital decompression can be used only in pathologies

localized to the medial, supero-medial and infero-medial regions of the bony orbit. Lesions

situated laterally are not accessible endoscopically and hence not amenable to treatment using

this approach.

Not all proptosed orbits need to be surgically decompressed.

1) In patients of Grave‟s ophthalmopathy, decompression should only be considered if

maximal medical therapy has failed to control the proptosis, and there is clinical evidence

of non-improvement or progressive visual loss

2) In some patients with post-traumatic proptosis, a carotico-cavernous fistula may develop,

this diagnosis can be made by an MRI Angiogram, and more specifically with a DSA.

The presence of an early draining vein during the arterial phase, coupled with a dilated

superior ophthalmic vein on Magnetic Resonance Angiography may help in arriving at

the diagnosis. The management is by an Interventional Neuro Radiologist using the

technique of embolisation of the feeding vessel with steel coils to occlude the fistula,

with dramatic results.

Fig: Clinical photograph of a patient with a post traumatic carotico-cavernous fistula

affecting the left eye and presenting as proptosis, chemosis and visual loss, mimicking

symptoms of an orbital haematoma



Fig: the T2 weighted MRI Scan showing the dilated superior ophthalmic vein on the left

side

Fig. MR Angiogram showing evidence of an early draining vein in the arterial phase, on

the left side, suggestive of a carotico-cavernous fistula.



Fig. Digital Subtraction Angiogram confirming the MRA findings in Fig.

Fig. The successful occlusion of the abnormal communication after embolisation using

steel coils.



Fig. Clinical photograph of the same patient post-embolisation showing a dramatic

reduction in the proptosis.

Complications:

“Sun-setting” of the orbit- This occurs, if during the decompression, too much of the

orbital floor is removed.

Injury to optic nerve- The optic nerve is most likely to be injured in the region of the

orbital apex while performing an over-enthusiastic orbital decompression.

Injury to medial rectus resulting in diplopia can occur if care is not taken while slitting

the orbital periosteum. The medial rectus runs close to the medial orbital wall in it‟s

medial one thirds and hence care should be taken not to slit the periosteum here.

Meticulous surgery yields good results in experienced hands (Fig. ).



Fig. The clinical photograph of the same patient as in Fig. showing complete recovery of

the proptosis and eye-movements after right orbital decompression for an orbital

haematoma. However, since the patient came late to us, exposure keratopathy had set in

prior to surgery which was eventually managed by the ophthalmologists.

CSF leak is likely to occur if the skull base is traumatised.

Obstruction of the Frontal Recess may occur if there is an over zealous removal of bone

in the antero-superior portion of the medial orbital wall. The orbital periosteum prolapses

into the frontal recess resulting in obstruction and subsequent iatrogenic sinusitis.

Hence, if the above is kept in mind during an orbital decompression, the results are good(Fig. ).

Fig. The Coronal view of the CT Scan of the same patient as in Fig. 7 days after left

orbital decompression and evacuation of pus, showing the orbital periosteum intact with the

orbital contents bulging into the ethmoidectomy cavity.



References:

1. PrabhakaranVC andSelva D. Orbital Endoscopic Surgery. Indian J Ophthalmol. 2008

Jan-Feb; 56(1): 5.

2. Gow JG. Harold Hopkins and optical systems for urology-an appreciation. Urology.

1998;52:152.

3. Norris JL, Cleasby GW. Endoscopic orbital surgery. Am J Ophthalmol. 1981;91:249.

4. Norris JL, Stewart WB. Bimanual endoscopic orbital biopsy: An emerging technique.

Ophthalmology. 1985;92:34.

5. Hajek M. Pathologie und Therapie der entzündlichenErkrankungen derNebenhöhlen der

Nase. 5th edn. TranzDeuticke: Leipzig, 1962.

6. Zuckerkandl E. Normale und pathologischeAnatomie der Nasenhöhle

undihrerPneumatischenAnhänge.II. Wilhelm Braumüller: Wien, 1892.

7. Onodi A. Die Nebenhöhlen der NasebeimKinde. Curt Kabitzsch:Würzburg, 1911.

8. Kennedy DW. Functional endoscopic sinus surgery. Technique. ArchOtolaryngol 1985

Oct;111(10):643-649.

9. Kennedy DW, Goodstein ML, Miller NR, Zinreich SJ. Endoscopictransnasal orbital

decompression. Arch Otolaryngol Head Neck Surg 1990Mar;116(3):275-282.

10. Michel O, Bresgen K, Rüssmann W, Thumfart WF, Stennert E.Endoscopically-controlled

endonasal orbital decompression in malignantexophthalmos. Laryngorhinootologie 1991Dec;70(12):656-662.

11. Al-Mujaini A, Wali U, Al-Khabori M. Functional Endoscopic Sinus Surgery: Indications

andComplications in Ophthalmic Field. Oman Medical Journal 2009; 24;(2):70-80.

12. Naffzinger HC. Progressive exophthalmos followingthyroidectomy: Its pathology &

Treatment. Ann Surg 1931;94:582-586

13. Sewall EC. Operative control of progressive exophthalmos.ArchOtolaryng H &N

Surgery 1936; 24:621-624

14. Hirsch O. Surgical decompression of exophthalmos. ArchOtolaryng H & N Surgery.

1950; 51:325-331

15. Walsh TE, Ogura JH. Transantral orbital decompressionfor malignant exophthalmos.Laryngoscope 1957; 67:544-549

16. Kennedy DW, Goodstein MD, Miller NR, Zinreich SJ.Endoscopic Transantral Orbital

Decompression. ArchOtolaryng Head & Neck Surg 1990; 116:275-282

Chapter Atlas- Endonasal Endoscopic Orbital Decompression

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