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Endoscopic-assisted clipping of cerebral aneurysms
Endoscopic-Assisted Clipping of Cerebral Aneurysms John G. Frazee, MD, Wesley A. King, MD, Antonio A. F. De Salles, MD, PhD, and Marvin Bergsneider, MD Although neuroendoscopy was first attempted in 1910, much of the work in its development has occurred in the last 5 years. Although conceptually very appealing, neuroendoscopy has been relatively limited in its scope because of a lack of instrumentation and applicable procedures. Instrumentation for endoscopes has been borrowed from other specialties and adapted to neurosurgery. Procedures have been, until recently, limited to the ventricular spaces. An important first step in the development of new applications has been an understanding of the neuroanatomy as viewed through the limited portal of the endoscope. Perneczky et aP have made a nice contribution toward this goal with the publication of their textbook on neuroendoscopic anatomy. The use of the endoscope for approaching the subarachnoid space and particularly the vascular system is a very new concept. 2 The adaptation of the endoscope for vascular surgery faces the same problems that occurred with the use of the operating microscope in neurosurgery. It was clear that the surgical microscope could provide a good quality magnified view of the surgical field, but there was great difficulty for the operating surgeon in adjusting to this new apparatus. For surgeons used to operating on an aneurysm without magnification, the microscope proved to be a confusing tool. It required relearning the anatomy from a magnified perspective and learning to adjust to emergency conditions such as aneurysm rupture without removing the microscope. This process is being repeated with the endoscope. We have gained endoscopic experience in the subarachnoid space using more than 40 cadaver heads. This experience ensured a smooth transition to patient application. We have had endoscopic experience in 10 patients with ruptured intracranial aneurysms. Our experience suggests that with current technology, it is possible to visualize, dissect, and clip aneurysm using only the endoscope for visualization. We have used each of the
From the Department of Neurosurgery, UCLA Center for the Health Sciences, Los Angeles, CA; and the Department of Neurosurgery, Mount Sinai MedicalSchool,New York,NY. Address reprint requests to John G. Frazee, MD, Department of Neurosurgery, 18-211NPI, UCLACenter for the Health Sciences, Los Angeles, CA 90095. Copyright 9 1997by National StrokeAssociation 1052-3057/97/0604-002053.00/0
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three popular forms of endoscopes, rigid, flexible, and penscope to visualize aneurysms, their necks, and adjacent structures, including perforators and cranial nerves. Each scope provided special benefits and had unique drawbacks. All endoscopic work was done using a three-chip video camera, high-resolution monitor, a xenon light source, and a super VHS tape recorder. In some cases, images were also captured in digital format using a removable hard disc. In each surgical case, the endoscopic work was done after a routine craniotomy had been created and the microscope draped. This was to ensure the greatest possible safety, especially in one instance in which the aneurysm was dissected and clipped using only the penscope. There were no complications in any of the 10 cases.
Rigid
Scope
The Gaab scope (Codman; Johnson and Johnson Professional, Inc., Randolph, MA) is approximately 6 m m in diameter, with an irrigating and working channel. The optics are glass and afford the very best optical picture. The scope has interchangeable angled optics for viewing around corners. The video camera is attached directly to the viewing end, making the scope heavy and difficult to maneuver around delicate structures.
Steerable Scope This scope (Codman) has a 4-mm tip and contains a working and irrigating channel. The tip is flexible in two directions (120 ~ and 90~ Fiber optics reduce the image size and clarity when compared with the rigid system, but the scope is much more maneuverable than the rigid system. Like the rigid system, the video connection is directly to the viewing end of the scope, and therefore, this scope also is heavy.
Penscope The pen endoscopes (Clarus Medical, Inc, Minneapolis, MN) are the most recent novel development in the neuroendoscopic field. The introduction of the pen endoscope, a lightweight, disposable endoscope similar in size
Journal of Stroke and Cerebrovascular Diseases, Vol. 6, No. 4, 1997: pp 240-241
241
CEREBRAL ANEURYSM CLIPPING
and shape to the Penfield dissector, has permitted the endoscopic neurosurgeon to look into spaces not readily approached by other more cumbersome scopes. These scopes are rigid, short, and are designed to be held in one hand. The optics are through a fiber cable, and, because of the reduced number of fibers, these scopes do not give a picture quality as good as that of the flexible endoscopes. However, they are excellent for a disposable system. An irrigating channel is included in this scope. Because the optics, light source, and irrigation system are off loaded, these endoscopes are very lightweight.
results then were confirmed with the operating microscope. The penscope has been used in a number of aneurysm surgeries. In most cases, the scope has been used as an adjunct to microsurgery, such as viewing perforating vessels located out of the direct line of vision of the microscope, to insure that those vessels are free from the aneurysmal neck and not included in the aneurysm clip. It is clear that in some instances the penscope can be used as the sole means of vision for clipping an aneurysm.
Summary Illustrative Case We have used the penscope with a 5-ram focal length and 3-n~rn ball tip to dissect and clip a previously rupture pericallosal aneurysm. The operating microscope was available for this operation but was used only to confirm the results of clipping. The use of this endoscope to clip an aneurysm was attempted only after extensive experience with endoscopes during routing surgery for aneurysms and trials in cadavers. A standard craniotomy was created for a midline approach to this aneurysm, which was located just beyond the genu of the corpus callosum. The dura was opened widely so that the operating microscope could be used if necessary. With continuous irrigation from the penscope, held in the left hand, and using a microdissector in the right hand, the interhemispheric dissection was carried down to the corpus callosum. The endoscope image clearly showed the site of the subarachnoid hemorrhage, and it was readily possible to dissect both the proximal and distal pericallosal artery. The aneurysmal neck and a tightly adherent perforator were then dissected, and a single aneurysm clip was applied. The
Our experience suggests that, with current technology, it is possible to visualize, dissect, and clip cerebral aneurysm using only the endoscope for visualization. Each of the endoscopes requires little or no brain retraction and could be introduced through a bur hole. The penscope would need the largest opening (1.0 x 1.5 cm), because work is done alongside the scope. However, it overcomes the inherent problem of bur hole surgery for aneurysms: what to do in case of a rupture. Working through a slightly larger opening allows the introduction of other instruments outside of and parallel to the penscope, such as suction and aneurysm clips. The penscope is, therefore, most currently suited for aneurysm surgery.
References 1. Perneczky A, Tschabitscher M, Resch KDM. Endoscopic anatomy for neurosurgery. New York: Thieme Medical Publications, 1993. 2. King WA, Frazee JG, Teo C, Wackym PA. Endoscopic treatment of cranial base lesions. In: King WA, Frazee JG, DeSalles AAF, eds. Endoscopy of the central and peripheral nervous system. New York: Thieme, (in press).
From the Department of Neurosurgery, UCLA Center for the Health Sciences, Los Angeles, CA; and the Department of Neurosurgery, Mount Sinai MedicalSchool,New York,NY. Address reprint requests to John G. Frazee, MD, Department of Neurosurgery, 18-211NPI, UCLACenter for the Health Sciences, Los Angeles, CA 90095. Copyright 9 1997by National StrokeAssociation 1052-3057/97/0604-002053.00/0
240
three popular forms of endoscopes, rigid, flexible, and penscope to visualize aneurysms, their necks, and adjacent structures, including perforators and cranial nerves. Each scope provided special benefits and had unique drawbacks. All endoscopic work was done using a three-chip video camera, high-resolution monitor, a xenon light source, and a super VHS tape recorder. In some cases, images were also captured in digital format using a removable hard disc. In each surgical case, the endoscopic work was done after a routine craniotomy had been created and the microscope draped. This was to ensure the greatest possible safety, especially in one instance in which the aneurysm was dissected and clipped using only the penscope. There were no complications in any of the 10 cases.
Rigid
Scope
The Gaab scope (Codman; Johnson and Johnson Professional, Inc., Randolph, MA) is approximately 6 m m in diameter, with an irrigating and working channel. The optics are glass and afford the very best optical picture. The scope has interchangeable angled optics for viewing around corners. The video camera is attached directly to the viewing end, making the scope heavy and difficult to maneuver around delicate structures.
Steerable Scope This scope (Codman) has a 4-mm tip and contains a working and irrigating channel. The tip is flexible in two directions (120 ~ and 90~ Fiber optics reduce the image size and clarity when compared with the rigid system, but the scope is much more maneuverable than the rigid system. Like the rigid system, the video connection is directly to the viewing end of the scope, and therefore, this scope also is heavy.
Penscope The pen endoscopes (Clarus Medical, Inc, Minneapolis, MN) are the most recent novel development in the neuroendoscopic field. The introduction of the pen endoscope, a lightweight, disposable endoscope similar in size
Journal of Stroke and Cerebrovascular Diseases, Vol. 6, No. 4, 1997: pp 240-241
241
CEREBRAL ANEURYSM CLIPPING
and shape to the Penfield dissector, has permitted the endoscopic neurosurgeon to look into spaces not readily approached by other more cumbersome scopes. These scopes are rigid, short, and are designed to be held in one hand. The optics are through a fiber cable, and, because of the reduced number of fibers, these scopes do not give a picture quality as good as that of the flexible endoscopes. However, they are excellent for a disposable system. An irrigating channel is included in this scope. Because the optics, light source, and irrigation system are off loaded, these endoscopes are very lightweight.
results then were confirmed with the operating microscope. The penscope has been used in a number of aneurysm surgeries. In most cases, the scope has been used as an adjunct to microsurgery, such as viewing perforating vessels located out of the direct line of vision of the microscope, to insure that those vessels are free from the aneurysmal neck and not included in the aneurysm clip. It is clear that in some instances the penscope can be used as the sole means of vision for clipping an aneurysm.
Summary Illustrative Case We have used the penscope with a 5-ram focal length and 3-n~rn ball tip to dissect and clip a previously rupture pericallosal aneurysm. The operating microscope was available for this operation but was used only to confirm the results of clipping. The use of this endoscope to clip an aneurysm was attempted only after extensive experience with endoscopes during routing surgery for aneurysms and trials in cadavers. A standard craniotomy was created for a midline approach to this aneurysm, which was located just beyond the genu of the corpus callosum. The dura was opened widely so that the operating microscope could be used if necessary. With continuous irrigation from the penscope, held in the left hand, and using a microdissector in the right hand, the interhemispheric dissection was carried down to the corpus callosum. The endoscope image clearly showed the site of the subarachnoid hemorrhage, and it was readily possible to dissect both the proximal and distal pericallosal artery. The aneurysmal neck and a tightly adherent perforator were then dissected, and a single aneurysm clip was applied. The
Our experience suggests that, with current technology, it is possible to visualize, dissect, and clip cerebral aneurysm using only the endoscope for visualization. Each of the endoscopes requires little or no brain retraction and could be introduced through a bur hole. The penscope would need the largest opening (1.0 x 1.5 cm), because work is done alongside the scope. However, it overcomes the inherent problem of bur hole surgery for aneurysms: what to do in case of a rupture. Working through a slightly larger opening allows the introduction of other instruments outside of and parallel to the penscope, such as suction and aneurysm clips. The penscope is, therefore, most currently suited for aneurysm surgery.
References 1. Perneczky A, Tschabitscher M, Resch KDM. Endoscopic anatomy for neurosurgery. New York: Thieme Medical Publications, 1993. 2. King WA, Frazee JG, Teo C, Wackym PA. Endoscopic treatment of cranial base lesions. In: King WA, Frazee JG, DeSalles AAF, eds. Endoscopy of the central and peripheral nervous system. New York: Thieme, (in press).