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Why Use the Operating Microscope in Orbital Surgery?
Why Use the Operating Microscope in Orbital Surgery? John S. Kennerdell, MD Joseph C. Maroon, MD
and Paul Rehkopf, CCE Pittsburgh MICROSURGERY has become widely accepted in ophthalmology, neurosurgery, and otolaryngology. It is logical that it should provide an advantage in deep orbital surgery because of the narrowly confined space ftlled with important neural and vascular structures. Deep orbital tumors, especially
those of neural origin, should be approached by a microsurgical team that includes a neurosurgeon and an ophthalmologist. Superficially located neoplasms, such as benign mixed lacrimal gland tumors in which capsular integrity is mandatory, are also best excised with microtechniques.
APPROACHES Submitted for publication May 9, 1979. From the Departments of Ophthalmology, Neurology, and Neurosurgery, University of Pittsburgh, and the Eye & Ear Hospital, Pittsburgh. Reprint requests to Eye & Ear Hospital, 230 Lothrop Street, Pittsburgh, PA 15213 (Dr Kennerdell).
The most common approach for retrobulbar orbital tumors is the lateral orbitotomy (Fig 1).1• 2 This approach would be used for tumors that are superior, inferior, or lateral to the optic nerve, especially those inside the muscle cone. It also is used for tumors involving the optic nerve such as a meningioma or a glioma when it is conftned to the orbit.
Fig 1.-Lateral orbitotomy.
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V O LUME 86 NO VEMBER !979
OPERATTING MICROSCOPE
2041
\
Fig 2.-Supe rior orbitotomy.
The superior approac h is indicate d for posterior nasal orbital tumors involvin g the posterio r bony walls of the orbit or tumors3 located at the cranio-orbital junction (Fig 2). The anterior medial approac h is used for anterior nasal retrobu lbar tumors or optic nerve decompression in patients with chronic papilled ema (Fig 3).4
INSTRUMENTATION The self-retaining retracto rs (Fig 4) provide safe, stable retracti on of extraor bital and intraorb ital tissues, a feature that is essentia l for orbital microsurgery. The microsurgical dissectors are ideal for intricat e deep orbital dissection to separat e tumor
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KENNERDELL ET AL
AAO
Fig 3.-Anterior medial orbitotomy.
from other important structures with a minimum of trauma (Fig 5). These microsurgical dissectors and other neurosurgical instruments must have the appropriate bayonet curve, which is shortened to suit the orbital depth. The bayonet shape is necessary to avoid striking the microscope or obscuring visualization through the microscope while dissecting in the orbit. A bipolar cautery forceps, and, better yet, an irrigating bipolar cautery forceps (Fig 6), is used for safe cauterization of the small bleeding vessels and shrinkage of the small fat globules in the vicinity of important deep orbital structures.3
ADVANTAGE S The advantages of using the operating microscope include coaxial illumination, which provides magnified, shadow-free, brightly lit deeper orbital structures (Fig 7). The 250-mm objective is preferred for orbital microsurgery. With the zoom capability of 2-15X, it allows for precise dissection of the important small orbital structures (Fig 8). The incision need not extend more than 3 em posterior from the lateral canthus (Fig 9), and, therefore, the temporalis muscle does not need to be transected. It need only be removed from the zygoma and deeper sphenoid bone with a periosteal elevator. To obtain adequate exposure of the poste-
rior orbit, the greater wing of the sphenoid is partially removed, exposing the dura over the temporal lobe. Accurate dissection is made possible by microinstrument ation and a clear field is obtained using irrigating microcauterizatio n of the smaller bleeding vessels and the smaller fat globules.
RESULTS We have now done 30 deep micro-orbitotomies; the complications have been limited to two early cases. The first complication was persistent lateral rectus dysfunction due to adhesions and required a Supramid sleeve to partially restore the function of the lateral rectus. The second complication was in a woman with a hemangioma that was not known preoperatively to lie medial to the optic nerve. She suffered vision loss as a result of the manipulations necessary to bring the hemangioma temporally and remove it. The most gratifying results of the orbital microsurgery have been two successful operations to remove meningiomas confined to the orbit. The first case was a primarily extradural meningioma cuffing the optic nerve in mid orbit, and the second was an entirely intradural meningioma confined to the mid orbit. The first patient had visual recovery from counting fingers at one foot to
VOLUME 86 NOVEMRER 1979
OPERATING MICROSCOPE
Fig 4.-Self-retained retractors for lateral (top) and anterior medial (bottom) orbitotomies.
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KENNERDELL ET AL
OPHTH AAO
Fig 5.-Appropriately curved microsurgical instruments (top) and various tips of dissectors (bottom).
VOLUME 86 NOVEMBER
1979
OPERATING MICROSCOPE
• Fig G.-Irrigating bipolar cautery.
Fig 7.-Coaxial illumination of hemangioma.
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KENNERDELL ET AL
Fig 8.-Magnified visualization of optic nerve and hemangioma behind it.
Fig 9.-Three-centimeter incision with green contact lens protecting globe.
OPHTH AAO
VOLUME 86 NOVEMBER !979
OPERATING MICROSCOPE
20/20 with a nearly full field; the second patient had a central vision fluctuation postoperatively from 20/30 to 20/80, but there was marked improvement of her visual field.
2047
REFERENCES 1. Berke RN: A modified Kronlein operation. Trans Am Ophthalmol Soc 51:193-226, 1953.
2. Maroon JC, Kennerdell JS: Lateral microsurgical approach to intraorbital tumors. J Neurosurg 44:556-561, 1976.
SUMMARY We think the use of the operating microscope in deep orbital surgery is essential for a safer and more accurate removal of the tumors that occupy this difficult surgical location.
3. Kennerdell JS, Maroon JC: Microsurgical approach to intraorbital tumors. Arch Ophthalmol 94:1333-1336, 1976. 4. Galbraith JEK, Sullivan JH: Decompression of the perioptic meninges for relief of papilledema. Am J Ophthalmol 76:687692, 1973.
and Paul Rehkopf, CCE Pittsburgh MICROSURGERY has become widely accepted in ophthalmology, neurosurgery, and otolaryngology. It is logical that it should provide an advantage in deep orbital surgery because of the narrowly confined space ftlled with important neural and vascular structures. Deep orbital tumors, especially
those of neural origin, should be approached by a microsurgical team that includes a neurosurgeon and an ophthalmologist. Superficially located neoplasms, such as benign mixed lacrimal gland tumors in which capsular integrity is mandatory, are also best excised with microtechniques.
APPROACHES Submitted for publication May 9, 1979. From the Departments of Ophthalmology, Neurology, and Neurosurgery, University of Pittsburgh, and the Eye & Ear Hospital, Pittsburgh. Reprint requests to Eye & Ear Hospital, 230 Lothrop Street, Pittsburgh, PA 15213 (Dr Kennerdell).
The most common approach for retrobulbar orbital tumors is the lateral orbitotomy (Fig 1).1• 2 This approach would be used for tumors that are superior, inferior, or lateral to the optic nerve, especially those inside the muscle cone. It also is used for tumors involving the optic nerve such as a meningioma or a glioma when it is conftned to the orbit.
Fig 1.-Lateral orbitotomy.
2040
V O LUME 86 NO VEMBER !979
OPERATTING MICROSCOPE
2041
\
Fig 2.-Supe rior orbitotomy.
The superior approac h is indicate d for posterior nasal orbital tumors involvin g the posterio r bony walls of the orbit or tumors3 located at the cranio-orbital junction (Fig 2). The anterior medial approac h is used for anterior nasal retrobu lbar tumors or optic nerve decompression in patients with chronic papilled ema (Fig 3).4
INSTRUMENTATION The self-retaining retracto rs (Fig 4) provide safe, stable retracti on of extraor bital and intraorb ital tissues, a feature that is essentia l for orbital microsurgery. The microsurgical dissectors are ideal for intricat e deep orbital dissection to separat e tumor
2042
OPHTH
KENNERDELL ET AL
AAO
Fig 3.-Anterior medial orbitotomy.
from other important structures with a minimum of trauma (Fig 5). These microsurgical dissectors and other neurosurgical instruments must have the appropriate bayonet curve, which is shortened to suit the orbital depth. The bayonet shape is necessary to avoid striking the microscope or obscuring visualization through the microscope while dissecting in the orbit. A bipolar cautery forceps, and, better yet, an irrigating bipolar cautery forceps (Fig 6), is used for safe cauterization of the small bleeding vessels and shrinkage of the small fat globules in the vicinity of important deep orbital structures.3
ADVANTAGE S The advantages of using the operating microscope include coaxial illumination, which provides magnified, shadow-free, brightly lit deeper orbital structures (Fig 7). The 250-mm objective is preferred for orbital microsurgery. With the zoom capability of 2-15X, it allows for precise dissection of the important small orbital structures (Fig 8). The incision need not extend more than 3 em posterior from the lateral canthus (Fig 9), and, therefore, the temporalis muscle does not need to be transected. It need only be removed from the zygoma and deeper sphenoid bone with a periosteal elevator. To obtain adequate exposure of the poste-
rior orbit, the greater wing of the sphenoid is partially removed, exposing the dura over the temporal lobe. Accurate dissection is made possible by microinstrument ation and a clear field is obtained using irrigating microcauterizatio n of the smaller bleeding vessels and the smaller fat globules.
RESULTS We have now done 30 deep micro-orbitotomies; the complications have been limited to two early cases. The first complication was persistent lateral rectus dysfunction due to adhesions and required a Supramid sleeve to partially restore the function of the lateral rectus. The second complication was in a woman with a hemangioma that was not known preoperatively to lie medial to the optic nerve. She suffered vision loss as a result of the manipulations necessary to bring the hemangioma temporally and remove it. The most gratifying results of the orbital microsurgery have been two successful operations to remove meningiomas confined to the orbit. The first case was a primarily extradural meningioma cuffing the optic nerve in mid orbit, and the second was an entirely intradural meningioma confined to the mid orbit. The first patient had visual recovery from counting fingers at one foot to
VOLUME 86 NOVEMRER 1979
OPERATING MICROSCOPE
Fig 4.-Self-retained retractors for lateral (top) and anterior medial (bottom) orbitotomies.
2043
2044
KENNERDELL ET AL
OPHTH AAO
Fig 5.-Appropriately curved microsurgical instruments (top) and various tips of dissectors (bottom).
VOLUME 86 NOVEMBER
1979
OPERATING MICROSCOPE
• Fig G.-Irrigating bipolar cautery.
Fig 7.-Coaxial illumination of hemangioma.
2045
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KENNERDELL ET AL
Fig 8.-Magnified visualization of optic nerve and hemangioma behind it.
Fig 9.-Three-centimeter incision with green contact lens protecting globe.
OPHTH AAO
VOLUME 86 NOVEMBER !979
OPERATING MICROSCOPE
20/20 with a nearly full field; the second patient had a central vision fluctuation postoperatively from 20/30 to 20/80, but there was marked improvement of her visual field.
2047
REFERENCES 1. Berke RN: A modified Kronlein operation. Trans Am Ophthalmol Soc 51:193-226, 1953.
2. Maroon JC, Kennerdell JS: Lateral microsurgical approach to intraorbital tumors. J Neurosurg 44:556-561, 1976.
SUMMARY We think the use of the operating microscope in deep orbital surgery is essential for a safer and more accurate removal of the tumors that occupy this difficult surgical location.
3. Kennerdell JS, Maroon JC: Microsurgical approach to intraorbital tumors. Arch Ophthalmol 94:1333-1336, 1976. 4. Galbraith JEK, Sullivan JH: Decompression of the perioptic meninges for relief of papilledema. Am J Ophthalmol 76:687692, 1973.