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Petrosal approach: The avenue to the cerebellopontine angle and petrous apex
S22
Technology - Surgical Approaches and Endoscopy
I0-6-90 I Pedical fix~tjon for thoraco-Iumbar spinal tuberculosls
Tao-Chen Lee. Departmentof Neurosurgery. Chang Gung MemorialHospital
at Kaohsiung, Taiwan The Hong Kong method (radical debridement and anterior fusion) has dominated the field of treatment for thoracolumbar tuberculosis for a long time. However, recent reports have proved that anti-tuberculos is medication alone may also have good treatment results for this disease . In our department , we treat patents with anti-tuberculosis medication alone in case there is no evidence of segmenta l instability. When patients have thoracolumbar tuberculosis with clinical , as well as radiological evidence of spinal instability, transped icular instrumentat ion is pertormed in addition. In our series, 15 patients underwent pedicle fixation for segmental instability due to thoracolumbar tuberculos is. Among them, twelve patients needed a concormant neural decompression . Thirteen patients had good to excellent operative results. Pull-out of the implant was found in one patient. Persistent iower back pain was found in another patient. Both of these two patients had rather advanced tuberculous infection . In conclusion, transpedicular instrumentation is a good adjuvant for the treatment of early stage of thoracolumbar spinal tuberculosis with evidence of segmental instability.
Monday, 7 July 1997
14:00-16:30
0-7 Technology - Surgical Approaches and Endoscopy
I tumors
10 .7.91 Frontal orbital approaches to sellar and parasellar J.A. Landeiro, M.S. Flores, C.A. Lopes, M.A. Lapenta, C.H. Ribeiro. Brasilian
Air Force Hospital, Rio de Janeiro, Brasil Surgical access to lesions in and around the sella require a short working distance and minimum of brain retraction, considering that the work will be performed around the pituitary stalk, optic chiasm, carotid artery and its branches. These difficulties led the neurosurgeon to use a great number of surgical approaches . Among them, the orbital zygomatic and the lateral subfrontal approaches are the most suitable procedures. In the last two years, 26 tumors were approached by this route. They consisted of 14 pituitary tumors, 5 craniopharyingiomas, 2 chordomas, 2 optic nerve gliomas and 3 tuberculum sellae meningeomas. The final result was total removal in 19 cases and 2 post operative mortalities. Although the subfrontal lateral approach is not a new technique, it proves to be a more effective way to reach this site.
10-7-921 Transethmoidal approach to the skull base: Surgical anatomy G. Arango , M. Samii, L. Osterwa ld, M. Tatagiba. T. Brinker. NordstadtHospital,
Hannover. Germany Introduction: Anterior approaches to the skull base have clear indications in the modem management of previously so-called inoperable cases. In our Neurosurgical Department , with an experience of over 3000 skull base cases, the transethmoidal approach has become the transfacial approach of first choice given irs minimal morbidity, versat ility and extensive exposure. The aim of this study is to clarify the technique and skull base anatomy from the approaches sight of view as neurosurgeons must be familiar whh it's anatomy and potential exposure. Methods: Twenty cadaver heads fixed in formalin were used, six of them were addhionally colored in the vascular spaces. The transethmoidal approach was pertormed bilateraly in 5 specimens and unilateraly in 15. The lacrimal duct was preserved and a medial maxillectomy was always pertormed. Transsphenoldal and transchoanal dissections up to the skull base dissections were performed, Drilling the shell of bone covering the cavernous sinuses, petrous apex and clivus exposed the neurovascular structures immediately underlying. Results: The approach exposed the entire anterior skull base, the contralateral posteromedial orbit, optic nerve, cavernous sinus, foramen rotundum, vidian canal, petrous apex, Dorello's and hypoglossal canals, and the and the carotid in its C3, C4 and C5 portions . Medially the sella, entire clivus, foramen magnum , odontoid process and inferior limit of C1 were exposed. Opening of
Monday, 7 July 1997 the dura after drilling showed the prepontine and premedulary spaces and the contralateral CP-angle. Conclusions: Tumors such as chordomas , chondrosarcomas , angiofibromas, fibrous displasia, giant adenomas among others present frequently large extensions in the skull base and towards the sphenoid and preclival areas. They push or surround the neurovascular structures as they erode the bone thus demanding familiarity with the anatomy of this area. The transethmoidal approach provides an excellent cosmetic result, avoids the morbidity of other transfacial approaches, is familiar to most ENT colleagues and provides enough space and contralateral exposure to extensive skull base tumors.
I0 -7-931 cranial Aco~stic neurinoma surgery by extended middle fossa approach R. Shiobara, T. Ohira, T. Kawase, S. Toya, J. Kanzaki 1 • Departmentof
Neurosurgery, Keio University, School of Medicine, Tokyo, Japan, 1 Department of ENT, Keio University, School of Medicine Tokyo, Japan The extended middle cranial fossa approach , which we have modified and extended, is a subternporal transpetrosal transtentorial approach and is devised from the combination of Morrison and King's translabyrinthine-transtentorial approach and Bochenek's extended middle cranial fossa approach and is a team approach with cooperation between neurosurgeons and ENT surgeons . By means of this approach , the operative field can be extended according to tumor size and location, and through the wide operative field, safe operative procedures can be pertormed on the tumor, brain stem, AICA, facial nerve and cochlear nerve. During the past 20 years from 1976 to 1997, 560 cases of cerebellopontine angle tumor were operated on using the extended middle cranial fossa approach. Of the 560 cases acoustic neurinoma accounted for 454, meningioma for 54, epidermoid for 15, facial neurinoma for 11 and there were 20 other miscellaneous types. Reported herein are operative procedures and surgical results including a 0.4% overall mortality rate in 454 acoustic neurinoma operations . In the 401 initially operated cases of acoustic neurinoma the tumor was totally removed in 380 or 95% and, in 343 or 90% of the 380 cases , the facial nerve was anatomically preserved. Of the 380 cases, good function of the facial nerve (House-Brackmann Gr. I, II) was preserved in 288 (84%), fair function (GR. III, IV) in 41 (12%) and poor function (GR. V, VI) in 14 (4%). In 31 patients who underwent the facial-hypoglossal anastomosis to the sacrificed or preserved facial nerve with postoperative poor function, 2 are satisfied, 20 fairly and 9 not satisfied after anastomosis. In 76 cases or 52% of 145 cases in which hearing preservat ion was anempted, hearing was preserved postoperat ively, and useful hearing, which we consider to be under 50 dB average pure tone loss and over 50% of speech discriminat ion, was preserved in 55 cases or 37% of the 145 anempted cases.
I0-7-941
Petrosal approach: The avenue to the cerebellopontine angle and petrous apex
O. De Jesus. Universityof Puerto Rico, San Juan, Puerto Rico Introduction: Retrosigmoid exposure to the cerebellopontine angle (CPA) and petrous apex requires extensive retraction of the cerebellum . A presigmoid exposure has a shorter working distance and more anterolateral exposure . The petrosal approach provides a better exposure to this area with less retraction. Methods: During January t993 to March 1996, twenty-one consecutive patients were operated using the petrosal approach. There were 11 men and 10 women. Within the group, there were 14 neoplast ic lesions, six vascular lesions, and one hamartomatous lesion. Indications for the surgical approach for lesions in the superior and middle basal posterior cranial fossa are reviewed. Its use for the removal of giant acoustic schwannomas is reviewed, Results: Meningioma was the most common lesion. The tumor was completely removed in nine of the 14 tumors. Supratentorial extension through the tentorial notch was noted in seven patients. For aneurysms originated from the AICA, vertebrobasilar junction, mid basilar artery, and basilar trunk. The first three were clipped and the other was a giant fusiform aneurysm that was trapped. An AVM was found inoperable due to the intimate involvement of the brain stem. A dural AVF was occluded. Two patients in this series died. The surgical techniques of the petrosal approach and partial labyrinthectomy are reviewed. Conclusions: Skull base surgical techniques reduce the trauma of access by pertorming extradural bone resection. The petrosal approach provides exposure of the CPA, petrous apex, anterolateral cerebellum, and brain stem with less retraction than the retrosigmoid approach . Performing a partial labyrinthectomy will improve the surgical view. It can give ample exposure for giant acoust ic schwannomas. The petrosal approach offers the neurosurgical/neurotological team an improved view to the CPA, but the preferred route to the CPA will depend on the size and location of the tumor and the experience of the surgeon.
Technology - Surgical Approaches and Endoscopy
I0-6-90 I Pedical fix~tjon for thoraco-Iumbar spinal tuberculosls
Tao-Chen Lee. Departmentof Neurosurgery. Chang Gung MemorialHospital
at Kaohsiung, Taiwan The Hong Kong method (radical debridement and anterior fusion) has dominated the field of treatment for thoracolumbar tuberculosis for a long time. However, recent reports have proved that anti-tuberculos is medication alone may also have good treatment results for this disease . In our department , we treat patents with anti-tuberculosis medication alone in case there is no evidence of segmenta l instability. When patients have thoracolumbar tuberculosis with clinical , as well as radiological evidence of spinal instability, transped icular instrumentat ion is pertormed in addition. In our series, 15 patients underwent pedicle fixation for segmental instability due to thoracolumbar tuberculos is. Among them, twelve patients needed a concormant neural decompression . Thirteen patients had good to excellent operative results. Pull-out of the implant was found in one patient. Persistent iower back pain was found in another patient. Both of these two patients had rather advanced tuberculous infection . In conclusion, transpedicular instrumentation is a good adjuvant for the treatment of early stage of thoracolumbar spinal tuberculosis with evidence of segmental instability.
Monday, 7 July 1997
14:00-16:30
0-7 Technology - Surgical Approaches and Endoscopy
I tumors
10 .7.91 Frontal orbital approaches to sellar and parasellar J.A. Landeiro, M.S. Flores, C.A. Lopes, M.A. Lapenta, C.H. Ribeiro. Brasilian
Air Force Hospital, Rio de Janeiro, Brasil Surgical access to lesions in and around the sella require a short working distance and minimum of brain retraction, considering that the work will be performed around the pituitary stalk, optic chiasm, carotid artery and its branches. These difficulties led the neurosurgeon to use a great number of surgical approaches . Among them, the orbital zygomatic and the lateral subfrontal approaches are the most suitable procedures. In the last two years, 26 tumors were approached by this route. They consisted of 14 pituitary tumors, 5 craniopharyingiomas, 2 chordomas, 2 optic nerve gliomas and 3 tuberculum sellae meningeomas. The final result was total removal in 19 cases and 2 post operative mortalities. Although the subfrontal lateral approach is not a new technique, it proves to be a more effective way to reach this site.
10-7-921 Transethmoidal approach to the skull base: Surgical anatomy G. Arango , M. Samii, L. Osterwa ld, M. Tatagiba. T. Brinker. NordstadtHospital,
Hannover. Germany Introduction: Anterior approaches to the skull base have clear indications in the modem management of previously so-called inoperable cases. In our Neurosurgical Department , with an experience of over 3000 skull base cases, the transethmoidal approach has become the transfacial approach of first choice given irs minimal morbidity, versat ility and extensive exposure. The aim of this study is to clarify the technique and skull base anatomy from the approaches sight of view as neurosurgeons must be familiar whh it's anatomy and potential exposure. Methods: Twenty cadaver heads fixed in formalin were used, six of them were addhionally colored in the vascular spaces. The transethmoidal approach was pertormed bilateraly in 5 specimens and unilateraly in 15. The lacrimal duct was preserved and a medial maxillectomy was always pertormed. Transsphenoldal and transchoanal dissections up to the skull base dissections were performed, Drilling the shell of bone covering the cavernous sinuses, petrous apex and clivus exposed the neurovascular structures immediately underlying. Results: The approach exposed the entire anterior skull base, the contralateral posteromedial orbit, optic nerve, cavernous sinus, foramen rotundum, vidian canal, petrous apex, Dorello's and hypoglossal canals, and the and the carotid in its C3, C4 and C5 portions . Medially the sella, entire clivus, foramen magnum , odontoid process and inferior limit of C1 were exposed. Opening of
Monday, 7 July 1997 the dura after drilling showed the prepontine and premedulary spaces and the contralateral CP-angle. Conclusions: Tumors such as chordomas , chondrosarcomas , angiofibromas, fibrous displasia, giant adenomas among others present frequently large extensions in the skull base and towards the sphenoid and preclival areas. They push or surround the neurovascular structures as they erode the bone thus demanding familiarity with the anatomy of this area. The transethmoidal approach provides an excellent cosmetic result, avoids the morbidity of other transfacial approaches, is familiar to most ENT colleagues and provides enough space and contralateral exposure to extensive skull base tumors.
I0 -7-931 cranial Aco~stic neurinoma surgery by extended middle fossa approach R. Shiobara, T. Ohira, T. Kawase, S. Toya, J. Kanzaki 1 • Departmentof
Neurosurgery, Keio University, School of Medicine, Tokyo, Japan, 1 Department of ENT, Keio University, School of Medicine Tokyo, Japan The extended middle cranial fossa approach , which we have modified and extended, is a subternporal transpetrosal transtentorial approach and is devised from the combination of Morrison and King's translabyrinthine-transtentorial approach and Bochenek's extended middle cranial fossa approach and is a team approach with cooperation between neurosurgeons and ENT surgeons . By means of this approach , the operative field can be extended according to tumor size and location, and through the wide operative field, safe operative procedures can be pertormed on the tumor, brain stem, AICA, facial nerve and cochlear nerve. During the past 20 years from 1976 to 1997, 560 cases of cerebellopontine angle tumor were operated on using the extended middle cranial fossa approach. Of the 560 cases acoustic neurinoma accounted for 454, meningioma for 54, epidermoid for 15, facial neurinoma for 11 and there were 20 other miscellaneous types. Reported herein are operative procedures and surgical results including a 0.4% overall mortality rate in 454 acoustic neurinoma operations . In the 401 initially operated cases of acoustic neurinoma the tumor was totally removed in 380 or 95% and, in 343 or 90% of the 380 cases , the facial nerve was anatomically preserved. Of the 380 cases, good function of the facial nerve (House-Brackmann Gr. I, II) was preserved in 288 (84%), fair function (GR. III, IV) in 41 (12%) and poor function (GR. V, VI) in 14 (4%). In 31 patients who underwent the facial-hypoglossal anastomosis to the sacrificed or preserved facial nerve with postoperative poor function, 2 are satisfied, 20 fairly and 9 not satisfied after anastomosis. In 76 cases or 52% of 145 cases in which hearing preservat ion was anempted, hearing was preserved postoperat ively, and useful hearing, which we consider to be under 50 dB average pure tone loss and over 50% of speech discriminat ion, was preserved in 55 cases or 37% of the 145 anempted cases.
I0-7-941
Petrosal approach: The avenue to the cerebellopontine angle and petrous apex
O. De Jesus. Universityof Puerto Rico, San Juan, Puerto Rico Introduction: Retrosigmoid exposure to the cerebellopontine angle (CPA) and petrous apex requires extensive retraction of the cerebellum . A presigmoid exposure has a shorter working distance and more anterolateral exposure . The petrosal approach provides a better exposure to this area with less retraction. Methods: During January t993 to March 1996, twenty-one consecutive patients were operated using the petrosal approach. There were 11 men and 10 women. Within the group, there were 14 neoplast ic lesions, six vascular lesions, and one hamartomatous lesion. Indications for the surgical approach for lesions in the superior and middle basal posterior cranial fossa are reviewed. Its use for the removal of giant acoustic schwannomas is reviewed, Results: Meningioma was the most common lesion. The tumor was completely removed in nine of the 14 tumors. Supratentorial extension through the tentorial notch was noted in seven patients. For aneurysms originated from the AICA, vertebrobasilar junction, mid basilar artery, and basilar trunk. The first three were clipped and the other was a giant fusiform aneurysm that was trapped. An AVM was found inoperable due to the intimate involvement of the brain stem. A dural AVF was occluded. Two patients in this series died. The surgical techniques of the petrosal approach and partial labyrinthectomy are reviewed. Conclusions: Skull base surgical techniques reduce the trauma of access by pertorming extradural bone resection. The petrosal approach provides exposure of the CPA, petrous apex, anterolateral cerebellum, and brain stem with less retraction than the retrosigmoid approach . Performing a partial labyrinthectomy will improve the surgical view. It can give ample exposure for giant acoust ic schwannomas. The petrosal approach offers the neurosurgical/neurotological team an improved view to the CPA, but the preferred route to the CPA will depend on the size and location of the tumor and the experience of the surgeon.