3-D VIDEO
Microsurgical Clipping of a Superior Hypophyseal Artery Aneurysm: Part 2: Distal Dural Ring Dissection and Clipping: 3-Dimensional Operative Video Arnau Benet, MD,* Jordina Rincon-Torroella, MD,‡ Michael T. Lawton, MD* *Department of Neurosurgery, University of California, San Francisco, California; ‡Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland
Anterior clinoidectomy is a gateway to the complex anatomy of the clinoidal segment of the internal carotid artery (ICA), proximal branch arteries, the distal dural ring, and the necks of paraclinoid aneurysms. After anterior clinoidectomy, the cavernous sinus is controlled with fibrin glue injection, the dural ring is incised circumferentially, the optic strut is drilled further, and the ICA is released from its dural attachments. These maneuvers access the aneurysm neck for clipping. This 3-dimensional (3-D) video illustrates the microsurgical clipping of a large left superior hypophyseal artery (SHA) aneurysm in a 56-year-old woman. Part 1 demonstrates anterior clinoidectomy, and Part 2 demonstrates dural ring dissection and aneurysm clipping. Additionally, 3-D cadaveric specimens illustrate surgical anatomy and emphasize the need for cadaveric dissection. The medial projection of SHA aneurysms away from the surgical trajectory interposes the ICA between the neurosurgeon and the aneurysm neck, making it difficult to view the pathology completely and requiring the use of tandem, angled fenestrated clips to ensure adequate closing forces of the blades. The complex morphology of inflow and outflow arteries requires multiple clips that reconstruct the curves of the parent artery, as in this case. Microsurgical clipping of SHA aneurysms is challenging because the pathology is complex, clip application is incompletely visualized in the dark medial spaces, and the optic nerve is an unforgiving obstacle. This video is intended to increase familiarity with SHA aneurysms because endovascular advances are decreasing the surgical indications for
OPERATIVE NEUROSURGERY
Watch now at http://bit.ly/1xKw6QP
these lesions and diminishing our collective proficiency in managing them with open microsurgery. The 3-D video can be viewed at http://bit.ly/ 1xKw6QP or to view on a mobile device, scan this QR Code to link to an anaglyph (red/green) version of this 3-D video. Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. Dr Rincon-Torroella is a recipient of the 2013 “La Caixa” Fellowship Grant.
COMMENT
T
his is an outstanding technical video by Dr Lawton and his colleagues describing the exposure and clipping of a large superior hypophyseal artery region aneurysm. Several details emphasized by Dr Lawton are worth repeating. Leaving intact the arachnoid overlying the optic nerve until the later stages of the dissection is important to protect the optic nerve during early manipulation. Minimizing the use of the retractor and thinking of it as a “temporary clip” avoids prolonged and unnecessary compression of the brain. Using fenestrated clips to occlude the portion of the aneurysm neck further away from the surgeon is important. Whereas straight clips are weaker distally, fenestrated clips are stronger. It is unlikely that a straight clip will occlude the far portion of the neck, particularly given the thick tissue found at the aneurysm neck close to the fulcrum of the clip. The proximal fenestration of the clip avoids contact with this thick tissue, which prevents the tips from coming together. Reconstruction of the clinoidal curve of the internal carotid artery is invariably challenging in large and giant aneurysms and almost always requires application of multiple, small, fenestrated clips, as in this case. The use of intraoperative catheter angiography in these cases is essential to confirm the patency of the internal carotid artery.
Rafael J. Tamargo Baltimore, Maryland
VOLUME 11 | NUMBER 2 | JUNE 2015 | 359
Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited.
Microsurgical Clipping of a Superior Hypophyseal Artery Aneurysm: Part 2: Distal Dural Ring Dissection and Clipping: 3-Dimensional Operative Video Arnau Benet, MD,* Jordina Rincon-Torroella, MD,‡ Michael T. Lawton, MD* *Department of Neurosurgery, University of California, San Francisco, California; ‡Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland
Anterior clinoidectomy is a gateway to the complex anatomy of the clinoidal segment of the internal carotid artery (ICA), proximal branch arteries, the distal dural ring, and the necks of paraclinoid aneurysms. After anterior clinoidectomy, the cavernous sinus is controlled with fibrin glue injection, the dural ring is incised circumferentially, the optic strut is drilled further, and the ICA is released from its dural attachments. These maneuvers access the aneurysm neck for clipping. This 3-dimensional (3-D) video illustrates the microsurgical clipping of a large left superior hypophyseal artery (SHA) aneurysm in a 56-year-old woman. Part 1 demonstrates anterior clinoidectomy, and Part 2 demonstrates dural ring dissection and aneurysm clipping. Additionally, 3-D cadaveric specimens illustrate surgical anatomy and emphasize the need for cadaveric dissection. The medial projection of SHA aneurysms away from the surgical trajectory interposes the ICA between the neurosurgeon and the aneurysm neck, making it difficult to view the pathology completely and requiring the use of tandem, angled fenestrated clips to ensure adequate closing forces of the blades. The complex morphology of inflow and outflow arteries requires multiple clips that reconstruct the curves of the parent artery, as in this case. Microsurgical clipping of SHA aneurysms is challenging because the pathology is complex, clip application is incompletely visualized in the dark medial spaces, and the optic nerve is an unforgiving obstacle. This video is intended to increase familiarity with SHA aneurysms because endovascular advances are decreasing the surgical indications for
OPERATIVE NEUROSURGERY
Watch now at http://bit.ly/1xKw6QP
these lesions and diminishing our collective proficiency in managing them with open microsurgery. The 3-D video can be viewed at http://bit.ly/ 1xKw6QP or to view on a mobile device, scan this QR Code to link to an anaglyph (red/green) version of this 3-D video. Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. Dr Rincon-Torroella is a recipient of the 2013 “La Caixa” Fellowship Grant.
COMMENT
T
his is an outstanding technical video by Dr Lawton and his colleagues describing the exposure and clipping of a large superior hypophyseal artery region aneurysm. Several details emphasized by Dr Lawton are worth repeating. Leaving intact the arachnoid overlying the optic nerve until the later stages of the dissection is important to protect the optic nerve during early manipulation. Minimizing the use of the retractor and thinking of it as a “temporary clip” avoids prolonged and unnecessary compression of the brain. Using fenestrated clips to occlude the portion of the aneurysm neck further away from the surgeon is important. Whereas straight clips are weaker distally, fenestrated clips are stronger. It is unlikely that a straight clip will occlude the far portion of the neck, particularly given the thick tissue found at the aneurysm neck close to the fulcrum of the clip. The proximal fenestration of the clip avoids contact with this thick tissue, which prevents the tips from coming together. Reconstruction of the clinoidal curve of the internal carotid artery is invariably challenging in large and giant aneurysms and almost always requires application of multiple, small, fenestrated clips, as in this case. The use of intraoperative catheter angiography in these cases is essential to confirm the patency of the internal carotid artery.
Rafael J. Tamargo Baltimore, Maryland
VOLUME 11 | NUMBER 2 | JUNE 2015 | 359
Copyright © Congress of Neurological Surgeons. Unauthorized reproduction of this article is prohibited.
