- Email: [email protected]
Microsurgical anatomy of posterolateral approaches to the skull base
Thursday, 10 July 1997 nasopharyngeal carcinomas, 5 were neurofibromas. Twentyof the tumors were localizedboth inside and outside of the cranial cavity. Excisionof tumors located in the cranial base, along with the intracranial extension, the paranasal, the sphenoidsinusand the nasalcavity was difficult.This paperpresentsselectionof 3 approaches: (1) the extendedbifrontotemporal approach,intra-or extradurally, (2) the extracranial approach, and (3) the combined intra- and extracranial approach. Defects of the dura of the cranial base and of bone structures are also difficultto repair and may becomethe main cause of infectionof the cranial contents, and of CSF leakage in the postoperative period. The following key issues in the reconstruction of the anterior skull base are emphasized: (1) The nasal mucosa can be reconstructedwith a free skin gralt (2) Strictadherenceto dural closure at the skull base is paramount in the prevention of CSF leakage. This is accomplishedin 2 layers: the first is replacementof the defectivedura by periosteumor fascia from the leg, the second outer layer is reconstructed using periosteum of the frontal bone or temporal fascia containing the main trunk of the superficialtemporal artery. It allows repair or large defects of dura and bone. (3) If the dura of the cranial base is intact, a bone implant is not needed unless the bony defect is so large as to cause protrusion of the brain.
IP-S-64SI
A case of intracranial adenoid cystic carcinoma at the intra- and suprasellar region with an unknown primary site
Shinichi Sakamoto, Kenji Ohata, Naohiro Tsuyuguchi, NobuyukiShimokawa, MichiharuMorino, Akira Hakuba. Dept. of Neurosurgery, Osaka City Universify, Osaka, Japan Adenoid cystic carcinoma (ACC) is a relatively common head and neck tumor. Intracranial involvement by ACC can occur in one of the three ways: direct extension, hematogenousspread and perineural spread. Only eleven cases of intracranial ACC with an unknownprimary site have been reported. We present a case of intracranial ACC involVing the intra- and suprasellar region with an unknownprimary site. A34 years-oldfemale presentedwith a one monthhistory of visual disturbance and galactorrhea. MRI showed an intra- and suprasellar mass mimicking a pituitary adenoma. Alter transcranial resectionof the tumor, local recurrence and CSF dissemination to the lower clivus happened within two months. Pathological diagnosis was adenoid cystic carcinoma with 11% of Ki·67 index. A variety of tumor locations of intracranial ACC with an unknown primary site is presented together with a review of literature.
IP-S-646I
Treatment of malignant skull base tumors
Sergey V. Tanyashin" Vasiliy A. Tcherekaev" Igor V. Aeshetov2 , Alexander M. Sdvizkov 2. 1 Burdenko Neurosurgical Institute, Moscow, Russia, 2 p.A. HertzenCancerResearch Institute, Moscow, Russia Wehave a 3-yearsexperienceof surgical treatmentof 38 patientswith malignant skull base tumors (22 males and t6 females). By histological findings adenocarcinomas (7), plan-cellular carcinomas (8) basal-cellular carcinomas (3) and micro-cellular (15) were diagnosed. The tumor localisations were: craniofacial region - 24 cases, temporal region and middle fossa - 4 cases, petrous region and posterior fossa - 5 cases and sphenoid sinus - 5 cases. We used transfacial, orbitozygomatic, subtemporal and combined approaches. The operative methods included wide resection of soft tissues: (skin, muscles and dura) and cranial bones (orbital walls, zigomoid process, middle fossa base and petrous bone), Radiation therapy was performed in 11 patients before surgery, in 5 before and during surgery and in 24 - before and after surgery. In 12 cases the soft tissues plasty was made with skin, muscles and costal fragments. Plastic closure of the defects was performed with local tissues (rotated flap) in 3 cases, with musculocutaneous flap with preserved vascular supply in 3 cases and with microvascularanastomosisin 6 cases. All the patientsunderwentpostoperative chemotherapy. In all cases the operations were performed by a team of neurosurgeons, ENT and plastic surgeons. There were no postoperativemortality or complications. In a near 2-years period to patients had recurrences of tumors.
Tumours of the eNS - Orbital and Skull Base Tumours
S247
groupconsisted of 50 patients, with preoperativediagnosis based on CT for the first, and on MAl for the second group, accompaniedwith cerebral angiography in all cases. Results: Out of 100 cases, preoperativediagnosiswas confirmed in the first group89% (44), and 92% (46) in the second groupwith nostatisticalsignificance for this difference. Conclusion: Excludingselected rare cases in which MAl was necessary for a final decision and diagnosis, CT and angiography were sufficient for relevant preoperative diagnosis of sellar and juxtasellar expansions. Non-critical use of MRI only increased the expenseswith no adequate benefit in treatment.
IP-S-648I The clinical study of SIADH complicated by postoperative period of sellar region tumor YongGengzu, Xue Mingzhang, Guang Zhaoqin. Department of Neurosurgery, the SecondTextile WorkersHospital, Shanghai, China(Peoples Rep) 34 cases of Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH)were treated in our hospitalduring May 1984 to Dec 1995.The patients included 10 males and 24 females with age 17 to 70 years, average of 38.8 years. Of the 34 cases, 29 were pituitary adenomas, 3 craniopharyngiomas, 1 sellar region chordoma, t sellae tuberculum meningioma. All patients were diagnosedby MRI or CT scan in preoperation. After removal of the sellar region tumors, substitutiontherapy of steroid was given for one-two weeks. When the drugs were decreased gradually, but weren't discontinued in the postoperation 5--12days, these patientssufferedfrom SIADH.The mortality was O. This paper was aimed to observedthe changes of urinary output and urine gravity of these patients in the early period of SIADH; to analyse the causes of urinary output decline and urine gravity elevation; to discuss the relation between the test of urine gravity, urinary output and diagnosis of SIADH. The authors conclude: In the postoperativeperiodof sellar region tumor, the changes of urine gravity and urinary output will early indicate the occurrence of SIADH, which can appear earlier than the clinical symptoms and the laboratory's results of SIADH.
I P-S-649I Visual outcome and prognostic factors of surgical treatment of sellar and parasellar tumors YoungII Ha, Kwan YoungSong, Choong Hyun Kim, Dae Chul Ahim. Kangnam GeneralHospital, Seoul, Korea Introduction: The main complaints of sellar and parasellar tumors are visual disturbances (90%). This analysis was performed to determine the visual outcome and prognostic factors alter surgical treatment. Methods: A retrospective analysis was done of the clinical records of 48 patients who were surgicallytreated from 1989-1997. The lesions encountered consisted of pituitary adenoma in 28 cases, craniopharyngioma in 9 cases, meningiomain 5 cases, chordoma in 3 cases, optic glioma and dermoid cyst in t case each. The average duration of follow-up was 38 months. Parameters of predictingfactors for visual outcome were tumor pathoiogy, preoperative visual status,durationof symptomstumor size, visual evoked potential (VEP) and type of operation. Results: Visual acuity was normal or improved in 73% of the eyes and the visual fields were normal or improved in 71% postoperatively. The visual outcomeof postoperativevisual acuity was better in case of craniopharyngioma (78%) than in the other tumors. VEP showed post-operative improvement and was as help as visual fields in determining visual status. Conclusion: The visual outcome was belter in patients with a shorter duration of symptoms and in those with smaller tumors. Patients with less compromise of preoperativevisual acuity had better outcome of visual acuny, However, the severity of preoperative visual field defect did not seem to influence postoperative visual field outcome. There also was no relationship between the presence of endocrine activity of the tumor and visual outcome. Patients who underwent transsphenoidal approach had either better visual acuity or field improvementthan patients with transcranial approach.
IP-5-647I diagnostic Sellar and juxtasellar expansive lesions: Differential IP-5-650 I toMicrosurgical anatomy of posterolateral approaches the skull base problems LJ. Markovic 1 , M. Rakic, LJ. Djordjic, M. Jovanovic, V. Vuckovic, M. Janicijevic. 1 MilitaryMedicalAcademy, ClinicalCenterof Serbia, Belgrade, Yugoslavia, Institute for Neurosurgery, ClinicalCenterof Serbia, Belgrade, Yugoslavia Introduction: Precise preoperative differential diagnosis and adequate planning of surgery for sellar and juxtasellar expansive lesions can be a problem. Purposeof this study is to reveal the actual clinical significanceof CT, MAl and angiography in exact diagnosis and appropriate treatment of these lesions. Material: Two randomized groups of patients, operated at the Institute for Neurosurgeryand Military Medical Academy, Belgrade, with preoperative diagnosis of sellar, suprasellar or parasellar expansive lesions, were formed. Each
D.J. Mukhame~anov, U.B. Machmudov, I.N. Shevelev, B. Mbom, O.N. Myshkin, B.A. Smagulov. Burdenko Neurosurgical Institute, Moscow, Russia Introduction: Craniospinal pathology is a difficult surgical problem. The study of the microsurgical anatomy is necessary for surgeons planning operative approaches. Methods: Approacheswere studied on t2 preparations of cadaveric heads and six preparations of died patients with tumour of craniospinal localization, using magnifications from 2.5 up to 40 times. Arterial and venous vessels were filled, with colour latex. We performed micropreparations and measurements of anatomicalstructures. Investigatedstructures included vertebral arteries and its branches, veins and dural sinus, osteum, muscles, ligaments of the area
S248
Tumours of the eNS - Orbital and Skull Base Tumours
of crantovertebral junction, atlas and axis, the inferior cranial and superior spinal nerves, and the medulla. We simulated posteriolateral transcondylar approaches with stepwise resection of atlanto-ocipital junction. Results : Preparations of posteriolateral approaches allocating the vertebral artery, hypoglossal, glossopharyngeal , accessorius nerves and nervus vagus with their subsequent transposition , have allowed us to apply them in clinical practice at 9 patients with good outcomes. Conclusion: Studies on preparations for difficult approaches to the skull base permit application in clinical practice and may improve surgical results in the treatment of patients with tumours of the skull base.
I P-5-651
I The hypoglossal canal: An anatomical study
S. Pomonis, C.H.R. Christoforou , S. Spirat, M. Grammenou-Pomon is, D. Anagnostopoulos . Neurosurgical Unit, KAThospital, Kifisias avenue, Kifisia,
Athens, Greece Introduction: In skull base surgery and in particular for tumors involving the petroclival and foramen magnum regions , the lower cranial nerves including the hypoglossal , are at risk. Methods: Many approaches have been described for tumor resection from these regions, and their anatomy is well documented . In such approaches the occipital condyle and the hypoglossal canal may have to be drilled away for complete tumor removal. Results: The hypoglossal canal is located at the lateral parts of the occipital bone, above the anterior part of the occipital condyle. It may be partially or completely divided into two and transmits the hypoglossal nerve, a meningeal branch of the ascending pharyngeal artery and an emissary vein from the basilar plexus. Discussion: In this study we present the anatomy of the hypoglossal canal, and its use as a guide to approaches in skull base surgery.
I P-5-652I
Intracisternal accessory nerve neurinoma
L.J. Popovic , A. Momcilovic, D.J. Jajic, T. Cigic, P. Vulekovic,
Z. Kojadinovic .
University Neurosurgical Clinic, Novi Sad, Yugoslavia A case of neurinoma from the spinal accessory nerve which was located in the cisterna magna is reported. Two years before admission in hospital, a 29-years old woman suffered from serious attacks of vertigo and ataxia every time she extended and turned her head to the right. At the time of admission she had attacks of vertigo, nausea and vomiting when she tried to lie on the back or on the right side. Neurological exarnination in the standing and sitting position was normal. When she extended an turned to the right with the head neurological deficit appeared as instability and ataxia. Fundus examination showed swelling of the optic nerve. M.R.1. showed a tumor in the region of the cisterna magna. The tumor mass totally filled the cisterna magna and produced considerable hydrocephalus. The caudal pole of the tumor was at the upper level of C2. Through suboccipital craniectomy and C1 laminectomy the tumor was removed. The tumor was attached to the left spinal accessory nerve . The vascular supply, originating from the left P.I.C.A., was identified. Postoperative course was normal. On the control CT, signs of hydrocephalus were absent. Weakness of muscles , innervated by the spinal accessory nerve, was present at the time of the patient's demission. Two months later weakness of stemocleidomastoideus and trapez ius muscles were barely noticeable by clinical examination.
IP-5-653I The treatment of large acoustic neurinomas: Microsurgery, prophylaxis of ischemic complications
Thursday, lOluly 1997 of vasospasm and oedema in the area of operative intervention is observed after treatment with HBO. It also decrease the risk of postoperative inflammatory complications.
IP-5-654I follow-up Subtotal removal of acoustic neurinoma: Long-term stUdy A. Nishimoto 1 , M. Sakurai 2, K. Kunishio 2, K. Matsumoto 2, T. Ohmoto 2 . 1 Kagawa
Rosai Hospital, Marugame City. Japan, 20kayama University, Okayama Cily,Japan
Is total removal necessary or is subtotal removal suitable in acoustic neurinoma surgery in consideration of the quality of life of the patient? For evaluation of this question, long term follow-up study of the patients has been made. The first author operated 112 cases of acoustic neurinoma in Okayama University Hospital since 1966, and 71 cases between April 1980 and March 1991, when CT and microsurgery had been introduced and the operative technique had become standardized , the 71 patients investigated with CT and operated with microsurgery were analyzed . The tumor was removed by suboccipital transmeatal approach with care of avoiding facial nerve injury. Total removal was obtained in 35 cases, subtotal in 31 and partial in 5. There was no operative death and the patients were followed between 5 and 16 years (10 years on the average) . Tumor regrowth was found and reoperated in 1 of the total removal cases, 4 in the subtotal and 2 in the partial. Letter inqUiry in all cases and neurological as well as MR examination in 37 cases revealed no tumor regrowth except for above-mentioned 7 cases in this study. Twenty-four specimens from 20 patients were examined by immunohistochemical methods using Ki-67 monoclonal antibody and the labeling indices were 1.2 on average in 14 non-regrowth cases and 12.9 in 6 regrowth cases. The facial nerve was anatomically preserved in 22 cases of 35 total removal (63"10) and in 27 of 3t subtotal (87'Yo). The functional recovery was obtained in most cases atter 1 year but was incomplete in 12 cases (24%) atter long term follow-up . Postoperative recurrence or regrowth of acoustic neurinoma does not seem to be dependent on total or subtotal removal, but more likely depends on the proliferative potential of the tumor. Therefore, subtotal removal of the tumor leaving part of the capsule attached to the facial nerve, brain stem and internal acoustic meatus and preserve satisfactory postoperative facial nerve function may be a treatment of choice for the average neurosurgeon in consideration of the quali1y of life of the patients .
IP-5-655 I The os~eoplastlc lateral suboccipital approach for acoustic neurinoma surgery
A. Sepehrnia, U. Knopp. Neurosurgical Dept., Universityof Uibeck, Germany Introduction: Atter acoustic neurinoma surgery via the lateral suboccipital approach persistent headache remains a significant problem in a small group of patients. The advantage and disadvantage of the osteoplastic craniotomy is compared with the usually performed osteoclastic type . Methods: In our study 15 consecutive patients out of 50 underwent surgery for acoustic neurinoma via the osteoplastic lateral suboccip ital approach . Using a high-speed drill system the level of transverse sigmoid junction was exposed by a single burr-hole. A small channel was created and the craniotomy was placed along the sigmoid sinus. Results: We obtained superior cosmetic results utilizing this technique. No patient complained of postoperative head or neck pain. Discussion and Conclusion: The osteoplastic lateral suboccipital approach to the cerebello-pontine angle may avoid postoperative head and neck pain in patients and produces superior cosmetic results.
A.F. Smeyanovich, Y.G. Shanko . Research Institute of Neurology,
Neurosurgery and Physiotherapy. Minsk. Belarus There were 198 patients with large acoustic neurinomas, operated on in last 7 years: III degree - 34 (17.2%), IV degree - 164 (82.8%). Tumor excision was carried out by SUboccipital approach with the resection of posterior wall of porus acusticus internus in all cases. Total removal was performed in 181 (91.4%) cases and in 17 (8.6%) - subtotal , because it was impossible to separate pontine arachno id cover and tumor capsule . Facial nerve was preserved in 123 (62.1 'Yo) patients and its functional recovery was observed in 102 (82.9"10) cases. Mortality made up 1"10 (2 cases) and was caused by brain stem ischemia with haemorrhagic imbibition. Tumor recurrence was not observed till present lime. In our opinion, among the problems of large acoustic neurinomas surgery the postoperative brain stem ischemia is most important. Its manifestation largely depends of preoperative degree of brain stem function compensation. The success of surgery of large acoustic neurinomas depends on measures of prophylaxis and treatment of postoperative ischemic complications. Among them its necessary to mention the hyperbaric oxygenation (HBO), which produces an improvement of oxygen transport to the ischemic zone. The decrease
IP-5-656!
Craniocervical schwannomas
Mohammed EI Rajimany, Yousri El Adawy, Vasser EI Bana, Adel Issa.
Department of Neurosurgery. Faculty of Medicine, Alexandria University. Alexandria, Egypt Introduction: The craniocerv ical junction is a limited space in which several vital structures are contained. Surgical management of lesions of the craniacervical region often presents a challenge, because of the strategic location. Schwannomas arising in the region may have complex relations to the surrounding structures that may influence surgical decision taking as well as the surgical approach. We analyse the postoperative outcome of various surgical approaches for excision of craniocervical schwannomas . Methods: Eight cases of craniocervical schwannomas were both clinically and radiologically assessed . Surgery was performed in all patients and the intraoperative findings revealed a lesion arising either from the lower cranial nerves or from the upper cervical roots. Histopathological examination verified
IP-S-64SI
A case of intracranial adenoid cystic carcinoma at the intra- and suprasellar region with an unknown primary site
Shinichi Sakamoto, Kenji Ohata, Naohiro Tsuyuguchi, NobuyukiShimokawa, MichiharuMorino, Akira Hakuba. Dept. of Neurosurgery, Osaka City Universify, Osaka, Japan Adenoid cystic carcinoma (ACC) is a relatively common head and neck tumor. Intracranial involvement by ACC can occur in one of the three ways: direct extension, hematogenousspread and perineural spread. Only eleven cases of intracranial ACC with an unknownprimary site have been reported. We present a case of intracranial ACC involVing the intra- and suprasellar region with an unknownprimary site. A34 years-oldfemale presentedwith a one monthhistory of visual disturbance and galactorrhea. MRI showed an intra- and suprasellar mass mimicking a pituitary adenoma. Alter transcranial resectionof the tumor, local recurrence and CSF dissemination to the lower clivus happened within two months. Pathological diagnosis was adenoid cystic carcinoma with 11% of Ki·67 index. A variety of tumor locations of intracranial ACC with an unknown primary site is presented together with a review of literature.
IP-S-646I
Treatment of malignant skull base tumors
Sergey V. Tanyashin" Vasiliy A. Tcherekaev" Igor V. Aeshetov2 , Alexander M. Sdvizkov 2. 1 Burdenko Neurosurgical Institute, Moscow, Russia, 2 p.A. HertzenCancerResearch Institute, Moscow, Russia Wehave a 3-yearsexperienceof surgical treatmentof 38 patientswith malignant skull base tumors (22 males and t6 females). By histological findings adenocarcinomas (7), plan-cellular carcinomas (8) basal-cellular carcinomas (3) and micro-cellular (15) were diagnosed. The tumor localisations were: craniofacial region - 24 cases, temporal region and middle fossa - 4 cases, petrous region and posterior fossa - 5 cases and sphenoid sinus - 5 cases. We used transfacial, orbitozygomatic, subtemporal and combined approaches. The operative methods included wide resection of soft tissues: (skin, muscles and dura) and cranial bones (orbital walls, zigomoid process, middle fossa base and petrous bone), Radiation therapy was performed in 11 patients before surgery, in 5 before and during surgery and in 24 - before and after surgery. In 12 cases the soft tissues plasty was made with skin, muscles and costal fragments. Plastic closure of the defects was performed with local tissues (rotated flap) in 3 cases, with musculocutaneous flap with preserved vascular supply in 3 cases and with microvascularanastomosisin 6 cases. All the patientsunderwentpostoperative chemotherapy. In all cases the operations were performed by a team of neurosurgeons, ENT and plastic surgeons. There were no postoperativemortality or complications. In a near 2-years period to patients had recurrences of tumors.
Tumours of the eNS - Orbital and Skull Base Tumours
S247
groupconsisted of 50 patients, with preoperativediagnosis based on CT for the first, and on MAl for the second group, accompaniedwith cerebral angiography in all cases. Results: Out of 100 cases, preoperativediagnosiswas confirmed in the first group89% (44), and 92% (46) in the second groupwith nostatisticalsignificance for this difference. Conclusion: Excludingselected rare cases in which MAl was necessary for a final decision and diagnosis, CT and angiography were sufficient for relevant preoperative diagnosis of sellar and juxtasellar expansions. Non-critical use of MRI only increased the expenseswith no adequate benefit in treatment.
IP-S-648I The clinical study of SIADH complicated by postoperative period of sellar region tumor YongGengzu, Xue Mingzhang, Guang Zhaoqin. Department of Neurosurgery, the SecondTextile WorkersHospital, Shanghai, China(Peoples Rep) 34 cases of Syndrome of Inappropriate Secretion of Antidiuretic Hormone (SIADH)were treated in our hospitalduring May 1984 to Dec 1995.The patients included 10 males and 24 females with age 17 to 70 years, average of 38.8 years. Of the 34 cases, 29 were pituitary adenomas, 3 craniopharyngiomas, 1 sellar region chordoma, t sellae tuberculum meningioma. All patients were diagnosedby MRI or CT scan in preoperation. After removal of the sellar region tumors, substitutiontherapy of steroid was given for one-two weeks. When the drugs were decreased gradually, but weren't discontinued in the postoperation 5--12days, these patientssufferedfrom SIADH.The mortality was O. This paper was aimed to observedthe changes of urinary output and urine gravity of these patients in the early period of SIADH; to analyse the causes of urinary output decline and urine gravity elevation; to discuss the relation between the test of urine gravity, urinary output and diagnosis of SIADH. The authors conclude: In the postoperativeperiodof sellar region tumor, the changes of urine gravity and urinary output will early indicate the occurrence of SIADH, which can appear earlier than the clinical symptoms and the laboratory's results of SIADH.
I P-S-649I Visual outcome and prognostic factors of surgical treatment of sellar and parasellar tumors YoungII Ha, Kwan YoungSong, Choong Hyun Kim, Dae Chul Ahim. Kangnam GeneralHospital, Seoul, Korea Introduction: The main complaints of sellar and parasellar tumors are visual disturbances (90%). This analysis was performed to determine the visual outcome and prognostic factors alter surgical treatment. Methods: A retrospective analysis was done of the clinical records of 48 patients who were surgicallytreated from 1989-1997. The lesions encountered consisted of pituitary adenoma in 28 cases, craniopharyngioma in 9 cases, meningiomain 5 cases, chordoma in 3 cases, optic glioma and dermoid cyst in t case each. The average duration of follow-up was 38 months. Parameters of predictingfactors for visual outcome were tumor pathoiogy, preoperative visual status,durationof symptomstumor size, visual evoked potential (VEP) and type of operation. Results: Visual acuity was normal or improved in 73% of the eyes and the visual fields were normal or improved in 71% postoperatively. The visual outcomeof postoperativevisual acuity was better in case of craniopharyngioma (78%) than in the other tumors. VEP showed post-operative improvement and was as help as visual fields in determining visual status. Conclusion: The visual outcome was belter in patients with a shorter duration of symptoms and in those with smaller tumors. Patients with less compromise of preoperativevisual acuity had better outcome of visual acuny, However, the severity of preoperative visual field defect did not seem to influence postoperative visual field outcome. There also was no relationship between the presence of endocrine activity of the tumor and visual outcome. Patients who underwent transsphenoidal approach had either better visual acuity or field improvementthan patients with transcranial approach.
IP-5-647I diagnostic Sellar and juxtasellar expansive lesions: Differential IP-5-650 I toMicrosurgical anatomy of posterolateral approaches the skull base problems LJ. Markovic 1 , M. Rakic, LJ. Djordjic, M. Jovanovic, V. Vuckovic, M. Janicijevic. 1 MilitaryMedicalAcademy, ClinicalCenterof Serbia, Belgrade, Yugoslavia, Institute for Neurosurgery, ClinicalCenterof Serbia, Belgrade, Yugoslavia Introduction: Precise preoperative differential diagnosis and adequate planning of surgery for sellar and juxtasellar expansive lesions can be a problem. Purposeof this study is to reveal the actual clinical significanceof CT, MAl and angiography in exact diagnosis and appropriate treatment of these lesions. Material: Two randomized groups of patients, operated at the Institute for Neurosurgeryand Military Medical Academy, Belgrade, with preoperative diagnosis of sellar, suprasellar or parasellar expansive lesions, were formed. Each
D.J. Mukhame~anov, U.B. Machmudov, I.N. Shevelev, B. Mbom, O.N. Myshkin, B.A. Smagulov. Burdenko Neurosurgical Institute, Moscow, Russia Introduction: Craniospinal pathology is a difficult surgical problem. The study of the microsurgical anatomy is necessary for surgeons planning operative approaches. Methods: Approacheswere studied on t2 preparations of cadaveric heads and six preparations of died patients with tumour of craniospinal localization, using magnifications from 2.5 up to 40 times. Arterial and venous vessels were filled, with colour latex. We performed micropreparations and measurements of anatomicalstructures. Investigatedstructures included vertebral arteries and its branches, veins and dural sinus, osteum, muscles, ligaments of the area
S248
Tumours of the eNS - Orbital and Skull Base Tumours
of crantovertebral junction, atlas and axis, the inferior cranial and superior spinal nerves, and the medulla. We simulated posteriolateral transcondylar approaches with stepwise resection of atlanto-ocipital junction. Results : Preparations of posteriolateral approaches allocating the vertebral artery, hypoglossal, glossopharyngeal , accessorius nerves and nervus vagus with their subsequent transposition , have allowed us to apply them in clinical practice at 9 patients with good outcomes. Conclusion: Studies on preparations for difficult approaches to the skull base permit application in clinical practice and may improve surgical results in the treatment of patients with tumours of the skull base.
I P-5-651
I The hypoglossal canal: An anatomical study
S. Pomonis, C.H.R. Christoforou , S. Spirat, M. Grammenou-Pomon is, D. Anagnostopoulos . Neurosurgical Unit, KAThospital, Kifisias avenue, Kifisia,
Athens, Greece Introduction: In skull base surgery and in particular for tumors involving the petroclival and foramen magnum regions , the lower cranial nerves including the hypoglossal , are at risk. Methods: Many approaches have been described for tumor resection from these regions, and their anatomy is well documented . In such approaches the occipital condyle and the hypoglossal canal may have to be drilled away for complete tumor removal. Results: The hypoglossal canal is located at the lateral parts of the occipital bone, above the anterior part of the occipital condyle. It may be partially or completely divided into two and transmits the hypoglossal nerve, a meningeal branch of the ascending pharyngeal artery and an emissary vein from the basilar plexus. Discussion: In this study we present the anatomy of the hypoglossal canal, and its use as a guide to approaches in skull base surgery.
I P-5-652I
Intracisternal accessory nerve neurinoma
L.J. Popovic , A. Momcilovic, D.J. Jajic, T. Cigic, P. Vulekovic,
Z. Kojadinovic .
University Neurosurgical Clinic, Novi Sad, Yugoslavia A case of neurinoma from the spinal accessory nerve which was located in the cisterna magna is reported. Two years before admission in hospital, a 29-years old woman suffered from serious attacks of vertigo and ataxia every time she extended and turned her head to the right. At the time of admission she had attacks of vertigo, nausea and vomiting when she tried to lie on the back or on the right side. Neurological exarnination in the standing and sitting position was normal. When she extended an turned to the right with the head neurological deficit appeared as instability and ataxia. Fundus examination showed swelling of the optic nerve. M.R.1. showed a tumor in the region of the cisterna magna. The tumor mass totally filled the cisterna magna and produced considerable hydrocephalus. The caudal pole of the tumor was at the upper level of C2. Through suboccipital craniectomy and C1 laminectomy the tumor was removed. The tumor was attached to the left spinal accessory nerve . The vascular supply, originating from the left P.I.C.A., was identified. Postoperative course was normal. On the control CT, signs of hydrocephalus were absent. Weakness of muscles , innervated by the spinal accessory nerve, was present at the time of the patient's demission. Two months later weakness of stemocleidomastoideus and trapez ius muscles were barely noticeable by clinical examination.
IP-5-653I The treatment of large acoustic neurinomas: Microsurgery, prophylaxis of ischemic complications
Thursday, lOluly 1997 of vasospasm and oedema in the area of operative intervention is observed after treatment with HBO. It also decrease the risk of postoperative inflammatory complications.
IP-5-654I follow-up Subtotal removal of acoustic neurinoma: Long-term stUdy A. Nishimoto 1 , M. Sakurai 2, K. Kunishio 2, K. Matsumoto 2, T. Ohmoto 2 . 1 Kagawa
Rosai Hospital, Marugame City. Japan, 20kayama University, Okayama Cily,Japan
Is total removal necessary or is subtotal removal suitable in acoustic neurinoma surgery in consideration of the quality of life of the patient? For evaluation of this question, long term follow-up study of the patients has been made. The first author operated 112 cases of acoustic neurinoma in Okayama University Hospital since 1966, and 71 cases between April 1980 and March 1991, when CT and microsurgery had been introduced and the operative technique had become standardized , the 71 patients investigated with CT and operated with microsurgery were analyzed . The tumor was removed by suboccipital transmeatal approach with care of avoiding facial nerve injury. Total removal was obtained in 35 cases, subtotal in 31 and partial in 5. There was no operative death and the patients were followed between 5 and 16 years (10 years on the average) . Tumor regrowth was found and reoperated in 1 of the total removal cases, 4 in the subtotal and 2 in the partial. Letter inqUiry in all cases and neurological as well as MR examination in 37 cases revealed no tumor regrowth except for above-mentioned 7 cases in this study. Twenty-four specimens from 20 patients were examined by immunohistochemical methods using Ki-67 monoclonal antibody and the labeling indices were 1.2 on average in 14 non-regrowth cases and 12.9 in 6 regrowth cases. The facial nerve was anatomically preserved in 22 cases of 35 total removal (63"10) and in 27 of 3t subtotal (87'Yo). The functional recovery was obtained in most cases atter 1 year but was incomplete in 12 cases (24%) atter long term follow-up . Postoperative recurrence or regrowth of acoustic neurinoma does not seem to be dependent on total or subtotal removal, but more likely depends on the proliferative potential of the tumor. Therefore, subtotal removal of the tumor leaving part of the capsule attached to the facial nerve, brain stem and internal acoustic meatus and preserve satisfactory postoperative facial nerve function may be a treatment of choice for the average neurosurgeon in consideration of the quali1y of life of the patients .
IP-5-655 I The os~eoplastlc lateral suboccipital approach for acoustic neurinoma surgery
A. Sepehrnia, U. Knopp. Neurosurgical Dept., Universityof Uibeck, Germany Introduction: Atter acoustic neurinoma surgery via the lateral suboccipital approach persistent headache remains a significant problem in a small group of patients. The advantage and disadvantage of the osteoplastic craniotomy is compared with the usually performed osteoclastic type . Methods: In our study 15 consecutive patients out of 50 underwent surgery for acoustic neurinoma via the osteoplastic lateral suboccip ital approach . Using a high-speed drill system the level of transverse sigmoid junction was exposed by a single burr-hole. A small channel was created and the craniotomy was placed along the sigmoid sinus. Results: We obtained superior cosmetic results utilizing this technique. No patient complained of postoperative head or neck pain. Discussion and Conclusion: The osteoplastic lateral suboccipital approach to the cerebello-pontine angle may avoid postoperative head and neck pain in patients and produces superior cosmetic results.
A.F. Smeyanovich, Y.G. Shanko . Research Institute of Neurology,
Neurosurgery and Physiotherapy. Minsk. Belarus There were 198 patients with large acoustic neurinomas, operated on in last 7 years: III degree - 34 (17.2%), IV degree - 164 (82.8%). Tumor excision was carried out by SUboccipital approach with the resection of posterior wall of porus acusticus internus in all cases. Total removal was performed in 181 (91.4%) cases and in 17 (8.6%) - subtotal , because it was impossible to separate pontine arachno id cover and tumor capsule . Facial nerve was preserved in 123 (62.1 'Yo) patients and its functional recovery was observed in 102 (82.9"10) cases. Mortality made up 1"10 (2 cases) and was caused by brain stem ischemia with haemorrhagic imbibition. Tumor recurrence was not observed till present lime. In our opinion, among the problems of large acoustic neurinomas surgery the postoperative brain stem ischemia is most important. Its manifestation largely depends of preoperative degree of brain stem function compensation. The success of surgery of large acoustic neurinomas depends on measures of prophylaxis and treatment of postoperative ischemic complications. Among them its necessary to mention the hyperbaric oxygenation (HBO), which produces an improvement of oxygen transport to the ischemic zone. The decrease
IP-5-656!
Craniocervical schwannomas
Mohammed EI Rajimany, Yousri El Adawy, Vasser EI Bana, Adel Issa.
Department of Neurosurgery. Faculty of Medicine, Alexandria University. Alexandria, Egypt Introduction: The craniocerv ical junction is a limited space in which several vital structures are contained. Surgical management of lesions of the craniacervical region often presents a challenge, because of the strategic location. Schwannomas arising in the region may have complex relations to the surrounding structures that may influence surgical decision taking as well as the surgical approach. We analyse the postoperative outcome of various surgical approaches for excision of craniocervical schwannomas . Methods: Eight cases of craniocervical schwannomas were both clinically and radiologically assessed . Surgery was performed in all patients and the intraoperative findings revealed a lesion arising either from the lower cranial nerves or from the upper cervical roots. Histopathological examination verified