- Email: [email protected]
Philosophy of skull base surgery: A lecture by Dr. Madjid Samii Lima, Peru; July 2, 1995
ELSEVIER
Neoplasm
PHILOSOPHY A LECTURE LIMA,
PERU;
I
OF SKULL BASE SURGERY: BY DR. MADJID SAMII JULY
2, 1995
n a special lecture before the World Federation Education Course held in Lima, Peru, July 3-7, 1995, Madjid Samii discussed the philosophy of skull base surgery. The skull base is defined as that area from the base of the skull extending intracranially or extracranially. Traditionally, neurosurgeons do not have training in surgery of the sinuses, orbit, or petrous bone. These areas were difficult for otolaryngologists, maxillofacial surgeons, or ophthalmologists individually, and the bridging areas were considered “no man’s land.” The cooperation of these specialties in the diagnosis and treatment of these lesions was necessary, and interdisciplinary approaches were needed. In regard to benign tumors, the aim of surgery is to completely excise the tumor and to preserve or reconstruct the neighboring structures of functional importance. For malignant tumors, an en bloc resection is ideal, but may be limited by the extent of the lesion and the potential outcome. In some cases, the surgery itself may disable the patient while providing no benefit. If life expectancy is short, surgery may even harm the patient and his or her family by reducing quality of life. Dr. Samii believes that some skull base surgeons are now being too aggressive in removing malignant lesions and that this surgery is unnecessary. Extensive surgery for malignant tumors involving both cavernous sinuses is contraindicated; also, for meningiomas that are benign but extensive, radical surgery is not indicated. Interdisciplinary work is essential, but difficult for some to understand. This is cooperative surgery in which each surgeon combines his or her skills with others’ for the benefit of the patient. Those who are willing to work cooperatively will have a better future in neurosurgery than those who insist on working alone. The future is in interdisciplinary work. Neuroradiology must be included in this team, particularly the interventionalists. We need 0090-3019/97/$17.00 PI1 SOO90-3019(96)00481-S
to know the vascular anatomy of the skull base, its osseous anatomy, and the relationship between the lesions and the nearby neurovascular structures. The neurosurgeon must be familiar with high resolution computed tomography (CT), threedimensional CT, superselective angiography, and magnetic resonance imaging (MRf) techniques in order to approach skull base lesions; all of this information must be reviewed by the skull base team preoperatively. Hemostasis at the skull base is achieved by bone wax, but can also be accomplished by “dry drilling,” in which the bone dust clogs the holes in the bleeding bone. For juvenile angioneurofibroma, preoperative angiography and embolization should be performed before radical removal of the tumor. If there is a malignant tumor of the orbit extending intracranially, exenteration of the orbit is required; a transcranial approach is not necessary as a supplement to this procedure. This is an example of how multidisciplinary approaches can provide simpler treatments than might be conceived without this cooperation. In esthesioneuroblastoma, unless there is a radical removal of tumor invading the dura at the base of the anterior fossa, the tumor will recur. Therefore, the lamina cribrosa and crista galli should be removed en bloc. The skull base should be reconstructed in multiple layers. For a malignant tumor, Dr. Samii states that you must consider all aspects of the patient’s life before choosing radical surgery. Meningiomas extending intracranially and extracranially can be resected using skull base ap-
proaches. Dr. Samii believes in the importance of preserving the venous drainage in operating on these tumors. For surgery of the cavernous sinus, he disagrees with those who state that tumors can be removed totally from the cavernous sinus, because the pa655 Avenue
0 1997 by Elsevier Science Inc. of the Americas, New York, NY 10010
Philosophy of Skull Base Surgery
Surg Neurol
155
1997:47:154-5
tient may be left with a significant disabling deficit. When there are no symptoms from cavernous sinus involvement, Dr. Samii generally does not remove the tumor to avoid leaving the patient with a deficit. If the tumor can be removed from the sinus easily, he will do it. Ultimately, the decision is based on the biologic behavior of the tumor and the patient’s quality of life. Dr. Samii does not believe in the anatomic triangles described for the cavernous sinus, because the pathology disturbs the normal relationships of these triangles. This triangle concept is only good for normal anatomy. He usually traces the nerves into the sinus and makes his dissections in this manner. Some tumors in the sella extending into the cavernous sinus are actually only compressing the sinus rather than invading it and can be removed transsphenoidally. For some very large pituitary tumors, bromocriptine can be given preoperatively to shrink the tumor. What price does the patient pay for radical surgery? This is the question the treating surgeon must ask. Are the costs of the surgery worth the benefits to the patient over the rest of his or her life? For example, generally chordomas cannot be cured by radical skull base surgery; the risks must be considered and balanced against the probable outcome.
M
THE
If a tumor such as a meningioma involves the artery, preoperative planning is essential to ensure circulation to the rest of the brain. Consideration of the anterior choroidal artery is crucial, Sacrifice of the carotid artery, producing a deficit from this vessel, may not be acceptable. The best method of ensuring the circulation is to provide an EC-IC bypass; however, this may not preserve the choroidal territory. It may be necessary to leave the tumor around the perforators and follow the patient carefully. For aneurysms of the cavernous sinus, radical skull base approaches are not indicated. EC-IC bypass or balloon occlusion provide the highest benefit at the lowest risk. Balloon occlusion, not surgery, is the treatment of choice for carotid cavernous Astula. Direct injection of the cavernous sinus with fibrin glue or muscle and glue is successful when no interventional treatment is available. Some skull base surgeons are hurting the patient more than the pathology, Dr. Samii said. If the outcome of the surgery is not going to benefit the patient, the surgery should not be done. carotid
EN HAVE AN EXTRAORDINARILY OPINION OF THEIR POSITION ERROR IS INERADICABLE. W. SOMERSET
James I. Ausman,
M.D., Ph.D.
Editor Chicago, Illinois
IN
ERRONEOUS NATURE; AND
MAUGHAM (1874-l 966), BRITISH AUTHOR “A WRITER’S NOTEBOOK,” 1896 ENTRY
Neoplasm
PHILOSOPHY A LECTURE LIMA,
PERU;
I
OF SKULL BASE SURGERY: BY DR. MADJID SAMII JULY
2, 1995
n a special lecture before the World Federation Education Course held in Lima, Peru, July 3-7, 1995, Madjid Samii discussed the philosophy of skull base surgery. The skull base is defined as that area from the base of the skull extending intracranially or extracranially. Traditionally, neurosurgeons do not have training in surgery of the sinuses, orbit, or petrous bone. These areas were difficult for otolaryngologists, maxillofacial surgeons, or ophthalmologists individually, and the bridging areas were considered “no man’s land.” The cooperation of these specialties in the diagnosis and treatment of these lesions was necessary, and interdisciplinary approaches were needed. In regard to benign tumors, the aim of surgery is to completely excise the tumor and to preserve or reconstruct the neighboring structures of functional importance. For malignant tumors, an en bloc resection is ideal, but may be limited by the extent of the lesion and the potential outcome. In some cases, the surgery itself may disable the patient while providing no benefit. If life expectancy is short, surgery may even harm the patient and his or her family by reducing quality of life. Dr. Samii believes that some skull base surgeons are now being too aggressive in removing malignant lesions and that this surgery is unnecessary. Extensive surgery for malignant tumors involving both cavernous sinuses is contraindicated; also, for meningiomas that are benign but extensive, radical surgery is not indicated. Interdisciplinary work is essential, but difficult for some to understand. This is cooperative surgery in which each surgeon combines his or her skills with others’ for the benefit of the patient. Those who are willing to work cooperatively will have a better future in neurosurgery than those who insist on working alone. The future is in interdisciplinary work. Neuroradiology must be included in this team, particularly the interventionalists. We need 0090-3019/97/$17.00 PI1 SOO90-3019(96)00481-S
to know the vascular anatomy of the skull base, its osseous anatomy, and the relationship between the lesions and the nearby neurovascular structures. The neurosurgeon must be familiar with high resolution computed tomography (CT), threedimensional CT, superselective angiography, and magnetic resonance imaging (MRf) techniques in order to approach skull base lesions; all of this information must be reviewed by the skull base team preoperatively. Hemostasis at the skull base is achieved by bone wax, but can also be accomplished by “dry drilling,” in which the bone dust clogs the holes in the bleeding bone. For juvenile angioneurofibroma, preoperative angiography and embolization should be performed before radical removal of the tumor. If there is a malignant tumor of the orbit extending intracranially, exenteration of the orbit is required; a transcranial approach is not necessary as a supplement to this procedure. This is an example of how multidisciplinary approaches can provide simpler treatments than might be conceived without this cooperation. In esthesioneuroblastoma, unless there is a radical removal of tumor invading the dura at the base of the anterior fossa, the tumor will recur. Therefore, the lamina cribrosa and crista galli should be removed en bloc. The skull base should be reconstructed in multiple layers. For a malignant tumor, Dr. Samii states that you must consider all aspects of the patient’s life before choosing radical surgery. Meningiomas extending intracranially and extracranially can be resected using skull base ap-
proaches. Dr. Samii believes in the importance of preserving the venous drainage in operating on these tumors. For surgery of the cavernous sinus, he disagrees with those who state that tumors can be removed totally from the cavernous sinus, because the pa655 Avenue
0 1997 by Elsevier Science Inc. of the Americas, New York, NY 10010
Philosophy of Skull Base Surgery
Surg Neurol
155
1997:47:154-5
tient may be left with a significant disabling deficit. When there are no symptoms from cavernous sinus involvement, Dr. Samii generally does not remove the tumor to avoid leaving the patient with a deficit. If the tumor can be removed from the sinus easily, he will do it. Ultimately, the decision is based on the biologic behavior of the tumor and the patient’s quality of life. Dr. Samii does not believe in the anatomic triangles described for the cavernous sinus, because the pathology disturbs the normal relationships of these triangles. This triangle concept is only good for normal anatomy. He usually traces the nerves into the sinus and makes his dissections in this manner. Some tumors in the sella extending into the cavernous sinus are actually only compressing the sinus rather than invading it and can be removed transsphenoidally. For some very large pituitary tumors, bromocriptine can be given preoperatively to shrink the tumor. What price does the patient pay for radical surgery? This is the question the treating surgeon must ask. Are the costs of the surgery worth the benefits to the patient over the rest of his or her life? For example, generally chordomas cannot be cured by radical skull base surgery; the risks must be considered and balanced against the probable outcome.
M
THE
If a tumor such as a meningioma involves the artery, preoperative planning is essential to ensure circulation to the rest of the brain. Consideration of the anterior choroidal artery is crucial, Sacrifice of the carotid artery, producing a deficit from this vessel, may not be acceptable. The best method of ensuring the circulation is to provide an EC-IC bypass; however, this may not preserve the choroidal territory. It may be necessary to leave the tumor around the perforators and follow the patient carefully. For aneurysms of the cavernous sinus, radical skull base approaches are not indicated. EC-IC bypass or balloon occlusion provide the highest benefit at the lowest risk. Balloon occlusion, not surgery, is the treatment of choice for carotid cavernous Astula. Direct injection of the cavernous sinus with fibrin glue or muscle and glue is successful when no interventional treatment is available. Some skull base surgeons are hurting the patient more than the pathology, Dr. Samii said. If the outcome of the surgery is not going to benefit the patient, the surgery should not be done. carotid
EN HAVE AN EXTRAORDINARILY OPINION OF THEIR POSITION ERROR IS INERADICABLE. W. SOMERSET
James I. Ausman,
M.D., Ph.D.
Editor Chicago, Illinois
IN
ERRONEOUS NATURE; AND
MAUGHAM (1874-l 966), BRITISH AUTHOR “A WRITER’S NOTEBOOK,” 1896 ENTRY