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Treatment of tuberculum sellae meningiomas:a long-term follow-up study
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Journal of Clinical Neuroscience (2001) 8(Supplement 1), 26–31 © 2001 Harcourt Publishers Ltd doi: 10.1054/jocn.2001.0873, available online at http://www.idealibrary.com on
Treatment of tuberculum sellae meningiomas: a long-term follow-up study Kohei Ohta MD, Kensaku Yasuo MD, Masashi Morikawa MD, Tatsuya Nagashima MD, Norihiko Tamaki MD Department of Neurosurgery, Kobe University School of Medicine, Kobe City, Japan
Summary Surgical techniques and their results for tuberculum sellae meningiomas were studied. Thirty-three cases, the first of which was operated in 1980, were analysed. There were 4 men and 29 women with an average age of 46.7 years. Eight cases underwent reoperations. The mean follow-up was 10.7 years. Approaches were pterional for 15 patients, FOZ/FO for 10, bilateral subfrontal for 6, and others for 2. Simpson’s grade (I, II, III, IV) were 12, 9, 0, and 12 cases respectively. Recurrence rate was 0% for grade I and 58.3% for grade IV. The FOZ/FO approach resulted in a lower Simpson’s grade (P:0.05), but other factors were not related to Simpson’s grade (P:0.05). The postoperative visual outcome did not depend on total (grade I and II) or subtotal (grade III and IV) removal (P:0.01). We conclude that radical removal of the tumours may result in lower recurrence rate without increasing surgical complications. Furthermore, skull base approaches can improve the rate of radical removal of tuberculum sellae meningiomas. © 2001 Harcourt Publishers Ltd Keywords: tuberculum sellae meningioma, recurrence, skull base surgery
INTRODUCTION
RESULTS
It is difficult to totally remove the tuberculum sellae meningioma, because it is surrounded by indispensable structures as the optic nerve and chiasma, pituitary stalk, and anterior choroidal artery. We examined the surgical techniques and analysed the results of operations for tuberculum sellae meningiomas by means of a long-term follow-up. In this paper, ‘recurrence’ refers to a state that requires a reoperation.
Simpson’s grade of Group B was worse than that of Group A (P:0.01). The recurrence rate was 0% for Simpson’s grade I, 11.1% for grade II, and 58.3% for grade IV, thus significantly higher than those for grade I or II (P:0.05). Intervals between the first and the second operation were 4.0 and 2.8 years for grade II and IV respectively (Fig. 5). Simpson’s grade after the FOZ/FO approach improved more than others (P:0.05) (Fig. 6). No other factors such as age, and pathological findings, were related to Simpson’s grade (P:0.05). As for radicality and postoperative neurological change (as mentioned earlier, this is almost the same as postoperative visual outcome), for the total removal group (including Simpson’s grade I and II), improvement and no change accounted for 42.9% each, and deterioration was 14.3%. The corresponding findings for the subtotal removal group (including Simpson’s grade IV) were 41.7%, 50.0%, and 8.3% (Fig. 7). There was no statistically significant difference between these two groups (P:0.01).
MATERIALS AND METHODS Thirty-three cases of tuberculum sellae meningiomas, initially operated on between February 1980 and January 2000 at our department, were analysed. They were divided into two groups: Group A, consisting of 25 cases who underwent a single operation (Table 1), and Group B of the remaining 8 cases who underwent reoperations (Table 2), once for 6 cases, and twice and three times for 1 case each. There were 4 men and 29 women with an average age of 46.7 years, ranging from 15 to 69 years old. The mean follow-up period was 10.7 years (Figs 1 and 2). Operative approaches consisted of five patterns, that is, pterional for 15 cases, fronto-orbito-zygomatic or fronto-orbito (FOZ/FO) for 10, bilateral subfrontal for 6, and interhemispheric and trans-sphenoidal for 1 each (Fig. 3). Twelve patients were Simpson’s grade I, 9 were grade II, none was grade III and 12 were grade IV (Fig. 4). Postoperative neurological changes were checked at the same time and were assessed in terms of the degree of improvement in visual acuity and/or visual field. They were classified into three groups; improvement, no change and deterioration. For this study, the records and clinical data of these cases were retrospectively analysed.
Correspondence to: Ohta Kohei, Department of Neurosurgery, Kobe University School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe city, 650-0017, Japan. Tel.:;81-78-382-5966; Fax:;81-78-382-5979
26
CASE STUDY The patient was a 40 year old female who was admitted to our hospital with a compliant of visual disturbance in both eyes for 1 year. Preoperative neurological examination revealed reduced visual acuity in both eyes, a partial defect of the visual field, and atrophic change in the optic disc of the left eye. Radiological examinations showed a mass lesion at the tuberculum sellae, slightly deviating to the left, which was homogeneously enhanced on both CT and MRI (Fig. 8). Preoperative MRI (Fig. 9) showed that the tumour compressed the optic chiasma in the same manner as a pituitary macroadenoma. The patient was operated on via the left fronto-orbito-zygomatic approach on January 13, 2000. The tumour was located between the optic nerve and the internal carotid artery on the left side and compressed them from below (Fig. 10). Because of paleness of the left optic nerve, the optic canal was unroofed on the same side (Fig. 11). Simpson’s grade I was attained without any surgical complications (Fig. 12). Visual disturbance has gradually improved and postoperative neurological change was classified as improvement. Sagittal and coronal views of postoperative gadolinium-enhanced MRI (Fig. 9) revealed no sign of a residual tumour.
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Treatment of tuberculum sellae meningiomas 27 Table 1
Summary of 25 cases of tuberculum sellae meningiomas treated with single operation (Group A)
No.
Sex
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
F F F F F F F F F F F M F F F F F M F F M F F F F
Age Laterality of tumour
40 33 42 55 58 48 55 65 40 58 34 57 46 41 52 63 53 51 48 60 69 40 37 41 34
Bilateral Bilateral Right Bilateral Left Left Bilateral Bilateral Bilateral Bilateral Right Bilateral Right Right Left Bilateral Bilateral Right Bilateral Bilateral Left Bilateral Left Bilateral Bilateral
Number of operations
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Operative approach
FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO Pterional FOZ/FO Pterional Pterional Pterional Pterional FOZ/FO Pterional Pterional Pterional Pterional Bilateral subfrontal Pterional Bilateral subfrontal Pterional Transsphenoidal Bilateral subfrontal
Simpson’s grade
Pathology
Postoperative neurological change
I I II II II I I I II I I II IV IV I II IV IV II I I I II IV I
Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Angiomatous Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial
Improvement Improvement No change Improvement Improvement No change Deterioration No change Improvement No change Improvement No change No change No change No change No change Improvement Deterioration Deterioration No change No change Improvement Deterioration Improvement Improvement
FOZ/FO: fronto-orbito-zygomatic or fronto-orbital. Table 2
Summary of eight cases of tuberculum sellae meningiomas treated with respected operations (Group B)
No.
Sex
Age
Laterality of tumour
Number of operations
Operative approach
Simpson’s grade
Pathology
26 27 28 29 30 31 32 33
M F F F F F F F
15 44 36 45 35 53 64 30
Bilateral Bilateral Bilateral Bilateral Left Bilateral Bilateral Bilateral
2 2 2 2 2 2 3 4
Bilateral subfrontal Pterional Pterional Pterional Pterional Bilateral subfrontal Bilateral subfrontal Interhemispheric
IV IV IV IV II IV IV IV
Meningothelial Meningothelial Malignant Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial
Postoperative neurological change No change No change Improvement Improvement Improvement Improvement No change No change
Fig. 1 Number of cases by sex in Groups A and B. Fig. 2 Patients’ age and follow-up duration (average) in Groups A and B.
DISCUSSION Tuberculum sellae meningioma is not common, accounting for about 6⬃12% of all intracranial meningiomas.1,2 Suprasellar meningioma often causes visual disturbance and remains undiagnosed until it has enlarged substantially or symptoms have © 2001 Harcourt Publishers Ltd
become aggravated.3 Visual loss is the initial and most common symptom.4–6 About 80% of patients suffer from visual disturbance for a period of between 3 months and 20 years with an average of more than 2 years.4,7,8 Tumours compress the optic chiasma, typically accompanied by bitemporal hemianopsia. In some cases, attachment of the tumour to the lateral part of the planum Journal of Clinical Neuroscience (2001) 8(Supplement 1) 26–31
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Fig. 6 Relationships between operative approaches and Simpson’s grade. Fig. 3 Number of cases in Groups A and B by operative approach.
Fig. 7 Postoperative neurological changes in relation to operative radicality based on Simpson’s grade. Fig. 4 Number of cases in Groups A and B by Simpson’s grade.
Fig. 5 Recurrence rate (%) and years until recurrence by Simpson’s grade.
sphenoidale or tuberculum sellae causes ipsilateral visual loss even if the size is relatively small.5 The unusually long period between the onset of symptoms and final diagnosis is a serious problem, because early diagnosis will increase the chance of a good postoperative visual outcome.4,7 An additional difficulty is that differential diagnosis of the suprasellar mass is still problematic because most patients with tuberculum sellae meningioma present with visual symptoms mimicking a pituitary macroadenoma.4 However an accurate diagnosis is important for the surgical approach, because tuberculum sellae
Journal of Clinical Neuroscience (2001) 8(Supplement 1) 26–31
meningioma often requires a craniotomy, whereas a transsphenoidal route is preferred for most pituitary macroadenomas.4,9 First of all, the diagnosis must be based on clinical symptoms and signs but preoperative MRI, especially the sagittal view, helps to establish an accurate diagnosis.4 Craniopharyngiomas and pituitary macroadenomas are the most common alternative diagnosis.10 The former can be diagnosed on the basis of the pattern of edema spread on MRI.11 The latter, however, are difficult to differentiate preoperatively from meningiomas despite recent advances in neurodiagnostic imaging. These tumours have no specific radiological features, and therefore several features must be combined to reach the correct diagnosis, mainly based on gadolinium-enhanced, thin section coronal and sagittal MRI.12 The difficulty of removing a tuberculum sellae meningioma totally without damaging optic nerves is well known because it is surrounded by indispensable structures, such as pituitary stalk and gland and the anterior choroidal artery. Various approaches and craniotomies, such as frontobasal interhemispheric and pterional approaches, are popular, but in some cases a trans-sphenoidal approach is used.4,10 Use of an operating microscope reportedly increases the total removal rate while lowering the mortality. Great care is required to separate optic nerves from the tumour to minimise damage to the optic chiasma and avoid damaging the feeding arteries of the optic nerves, especially for cases with longstanding and severe visual disturbance.5,8 Postoperative visual outcome has been reported as unacceptable, especially for large tumours.5 According to previous reports, postoperative visual function improved in about 55%, remained unchanged in 17⬃28%, and worsened in 19⬃25% of the patients.6,8 However, it was also reported that with appropriate preoperative management an excellent visual outcome can be expected,8,10 and that visual symptoms improved in almost all cases without any surgical complications.4,10
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Fig. 8 Preoperative enhanced CT scan (left) and MR image (right) show well-enhanced round mass at tuberculum sellae, slightly deviated to the left.
Fig. 9 Gadolinium-enhanced T1 weighted MR images, sagittal and coronal views. Preoperative MR images (upper) show the well-enhanced mass, compressing the pituitary chiasma from below. Postoperative MR images (lower) show the total resection.
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Fig. 10 Operative view of the illustrative case showed the tumour (arrow) between optic nerves (arrow with broken line) and internal carotid artery (arrow head), compressing them from below. The left optic nerve is pale.
Fig. 11 Pre- (upper) and post- (lower) operative bone window CT scans. (A) shows the optic canals on both sides. (B) is the plane 2 mm higher than the view in (A) and shows the roof of the topic canal. (C) shows the opening of an air sinus (arrow) and (D) clearly shows the unroofing of the optic canal on the left side (arrow head) when compared with (A) and (B).
Surgical outcome is affected by both tumour size and symptom duration.4,13 Patients with a tumour size of 3 cm or less and those with a duration of symptoms of 1 year or less had a better visual outcome, higher total removal rates, lower mortality rates, and lower recurrence rates. When the tumour exceeds 4 cm and compresses
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adjacent neurovascular structure, the possibility of total removal is limited and the chance for visual improvement is low.7,8 The recurrence rates of intracranial meningioma were 11.3% for total resection, and 42.9% and 66.7% for subtotal resection with or without radiation respectively. The overall recurrence rate was
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Treatment of tuberculum sellae meningiomas 31
Fig. 12 Operative view of the illustrative case after total removal of tumour. Pituitary stalk (arrow with dotted line) and unroofed optic canal on the left side can be seen.
19.5%.2 We could not find any reports on the exact recurrence rate of tuberculum sellae meningioma, but it is reasonable to assume it is rather high. Now the situation has changed because of skull base surgery accompanied by microsurgical techniques. Although the surgical procedures for tuberculum sellae meningioma are still difficult, appropriate preoperative imaging and careful intraoperative procedures have made it possible to have both total removal of tumours and an excellent visual outcome.5 Results of our cases reveal that the operation of the better Simpson’s grades (I, II) results in a lower recurrence rate. Because radical removal has no significant effect on the postoperative neurological changes, radical surgery should be undertaken to prevent either recurrence or reoperation. In order to perform a safe operation resulting in a better Simpson’s grade, skull base surgery, such as the fronto-orbitozygomatic approach, will be effective. For example, for a case of meningioma invading an optic canal, the optic canal must be opened positively.14 However, such radical operations sometimes result in unexpected opening of air sinuses following resection of the dural attachment to improve the Simpson’s grade. This injury can be repaired by closing by the pericranial flap with impinging fatty tissues to prevent postoperative CSF leakage.
REFERENCES
CONCLUSIONS
12.
Radical removal of the tuberculum sellae meningiomas resulted in lower recurrence rate without increasing surgical complications. Skull base approaches improved the extent of radical removal of the tuberculum sellae meningioma, and opening of the optic canal helped to improve radicality. Procedures involving the invaded dura and bone were important for achieving total removal of the tuberculum sellae meningioma.
© 2001 Harcourt Publishers Ltd
1. 2. 3.
4.
5.
6. 7. 8. 9. 10.
11.
13.
14.
Yao YT. Clinicopathologic analysis of 615 cases of meningioma with special reference to recurrence. J Formos Med Assoc 1994; 93: 145–152. Howng SL, Kwan AL. Intracranial meningioma. Kao Hsiung I Hsueh Ko Hsueh Tsa Chih 1992; 8: 312–319. Kinjo T, Mukawa J, Koga H, Shingaki T. An extensive cranial base meningioma extending bilaterally into Meckel’s cave: case report. Neurosurgery 1997; 40: 615–618. Leu CH, Hu TL, Shen CC, Wang YC. Tuberculum sellae meningiomas: clinical manifestation, radiologic diagnosis, surgery and visual outcome. Chung Hua I Hsueh Tsa Chih Taipei 1998; 61: 1–7. Uede T, Ohtaki M, Nonaka T, Tanabe S, Hashi K. Characteristics of visual impairment complicated with planum sphenoidale and tuberculum sellae meningiomas and their surgical results. No Shinkei Geka 1996; 24: 1093–1098. Gokalp HZ, Arasil E, Kanpolat Y, Balim T. Meningiomas of the tuberculum sella. Neurosurg Rev 1993; 16: 111–114. Marchel A, Bidzinski J, Barczewska M, Dziewiecki C. Meningiomas of sella turcica: some clinical aspects. Neurol Neurochir Pol 1996; 30: 93–100. Sakai N, Nakatani K, Sakai H, et al. Visual impairment complicated with meningioma. No To Shinkei 1991; 43: 851–856. Sintini M, Frattarelli M, Mavilla L. MRI of an unenhancing tuberculum sellae meningioma. Neuroradiology 1993; 35: 345–346. Van Effenterre R, Van Effenterre G, Cabanis EA, Iba Zizen MT. Suprasellar tumors in patients over 70 years of age. Value of limited frontotemporal craniotomy. Visual results. Apropos of 5 cases. Neurochirurgie 1991; 37: 330–337. Nagahata M, Hosoya T, Kayama T, Yamaguchi K. Edema along the optic tract: a useful MR finding for the diagnosis of craniopharyngiomas. AJNR Am J Neuroradiol 1998; 19: 1753–1757. Taylor SL, Barakos JA, Harsh GR 4th, Wilson CB. Magnetic resonance imaging of tuberculum sellae meningiomas: preventing preoperative misdiagnosis as pituitary macroadenoma. Neurosurgery 1992; 31: 621–627. Rosenstein J, Symon L. Surgical management of supracellar meningioma, Part 2: Prognosis for visual function following craniotomy. J Neurosurg 1984; 61: 642–648. DeMonte-F. Surgical treatment of anterior basal meningiomas. J Neurooncol 1996; 29: 239–248.
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Journal of Clinical Neuroscience (2001) 8(Supplement 1), 26–31 © 2001 Harcourt Publishers Ltd doi: 10.1054/jocn.2001.0873, available online at http://www.idealibrary.com on
Treatment of tuberculum sellae meningiomas: a long-term follow-up study Kohei Ohta MD, Kensaku Yasuo MD, Masashi Morikawa MD, Tatsuya Nagashima MD, Norihiko Tamaki MD Department of Neurosurgery, Kobe University School of Medicine, Kobe City, Japan
Summary Surgical techniques and their results for tuberculum sellae meningiomas were studied. Thirty-three cases, the first of which was operated in 1980, were analysed. There were 4 men and 29 women with an average age of 46.7 years. Eight cases underwent reoperations. The mean follow-up was 10.7 years. Approaches were pterional for 15 patients, FOZ/FO for 10, bilateral subfrontal for 6, and others for 2. Simpson’s grade (I, II, III, IV) were 12, 9, 0, and 12 cases respectively. Recurrence rate was 0% for grade I and 58.3% for grade IV. The FOZ/FO approach resulted in a lower Simpson’s grade (P:0.05), but other factors were not related to Simpson’s grade (P:0.05). The postoperative visual outcome did not depend on total (grade I and II) or subtotal (grade III and IV) removal (P:0.01). We conclude that radical removal of the tumours may result in lower recurrence rate without increasing surgical complications. Furthermore, skull base approaches can improve the rate of radical removal of tuberculum sellae meningiomas. © 2001 Harcourt Publishers Ltd Keywords: tuberculum sellae meningioma, recurrence, skull base surgery
INTRODUCTION
RESULTS
It is difficult to totally remove the tuberculum sellae meningioma, because it is surrounded by indispensable structures as the optic nerve and chiasma, pituitary stalk, and anterior choroidal artery. We examined the surgical techniques and analysed the results of operations for tuberculum sellae meningiomas by means of a long-term follow-up. In this paper, ‘recurrence’ refers to a state that requires a reoperation.
Simpson’s grade of Group B was worse than that of Group A (P:0.01). The recurrence rate was 0% for Simpson’s grade I, 11.1% for grade II, and 58.3% for grade IV, thus significantly higher than those for grade I or II (P:0.05). Intervals between the first and the second operation were 4.0 and 2.8 years for grade II and IV respectively (Fig. 5). Simpson’s grade after the FOZ/FO approach improved more than others (P:0.05) (Fig. 6). No other factors such as age, and pathological findings, were related to Simpson’s grade (P:0.05). As for radicality and postoperative neurological change (as mentioned earlier, this is almost the same as postoperative visual outcome), for the total removal group (including Simpson’s grade I and II), improvement and no change accounted for 42.9% each, and deterioration was 14.3%. The corresponding findings for the subtotal removal group (including Simpson’s grade IV) were 41.7%, 50.0%, and 8.3% (Fig. 7). There was no statistically significant difference between these two groups (P:0.01).
MATERIALS AND METHODS Thirty-three cases of tuberculum sellae meningiomas, initially operated on between February 1980 and January 2000 at our department, were analysed. They were divided into two groups: Group A, consisting of 25 cases who underwent a single operation (Table 1), and Group B of the remaining 8 cases who underwent reoperations (Table 2), once for 6 cases, and twice and three times for 1 case each. There were 4 men and 29 women with an average age of 46.7 years, ranging from 15 to 69 years old. The mean follow-up period was 10.7 years (Figs 1 and 2). Operative approaches consisted of five patterns, that is, pterional for 15 cases, fronto-orbito-zygomatic or fronto-orbito (FOZ/FO) for 10, bilateral subfrontal for 6, and interhemispheric and trans-sphenoidal for 1 each (Fig. 3). Twelve patients were Simpson’s grade I, 9 were grade II, none was grade III and 12 were grade IV (Fig. 4). Postoperative neurological changes were checked at the same time and were assessed in terms of the degree of improvement in visual acuity and/or visual field. They were classified into three groups; improvement, no change and deterioration. For this study, the records and clinical data of these cases were retrospectively analysed.
Correspondence to: Ohta Kohei, Department of Neurosurgery, Kobe University School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe city, 650-0017, Japan. Tel.:;81-78-382-5966; Fax:;81-78-382-5979
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CASE STUDY The patient was a 40 year old female who was admitted to our hospital with a compliant of visual disturbance in both eyes for 1 year. Preoperative neurological examination revealed reduced visual acuity in both eyes, a partial defect of the visual field, and atrophic change in the optic disc of the left eye. Radiological examinations showed a mass lesion at the tuberculum sellae, slightly deviating to the left, which was homogeneously enhanced on both CT and MRI (Fig. 8). Preoperative MRI (Fig. 9) showed that the tumour compressed the optic chiasma in the same manner as a pituitary macroadenoma. The patient was operated on via the left fronto-orbito-zygomatic approach on January 13, 2000. The tumour was located between the optic nerve and the internal carotid artery on the left side and compressed them from below (Fig. 10). Because of paleness of the left optic nerve, the optic canal was unroofed on the same side (Fig. 11). Simpson’s grade I was attained without any surgical complications (Fig. 12). Visual disturbance has gradually improved and postoperative neurological change was classified as improvement. Sagittal and coronal views of postoperative gadolinium-enhanced MRI (Fig. 9) revealed no sign of a residual tumour.
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Treatment of tuberculum sellae meningiomas 27 Table 1
Summary of 25 cases of tuberculum sellae meningiomas treated with single operation (Group A)
No.
Sex
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
F F F F F F F F F F F M F F F F F M F F M F F F F
Age Laterality of tumour
40 33 42 55 58 48 55 65 40 58 34 57 46 41 52 63 53 51 48 60 69 40 37 41 34
Bilateral Bilateral Right Bilateral Left Left Bilateral Bilateral Bilateral Bilateral Right Bilateral Right Right Left Bilateral Bilateral Right Bilateral Bilateral Left Bilateral Left Bilateral Bilateral
Number of operations
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Operative approach
FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO FOZ/FO Pterional FOZ/FO Pterional Pterional Pterional Pterional FOZ/FO Pterional Pterional Pterional Pterional Bilateral subfrontal Pterional Bilateral subfrontal Pterional Transsphenoidal Bilateral subfrontal
Simpson’s grade
Pathology
Postoperative neurological change
I I II II II I I I II I I II IV IV I II IV IV II I I I II IV I
Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Angiomatous Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial
Improvement Improvement No change Improvement Improvement No change Deterioration No change Improvement No change Improvement No change No change No change No change No change Improvement Deterioration Deterioration No change No change Improvement Deterioration Improvement Improvement
FOZ/FO: fronto-orbito-zygomatic or fronto-orbital. Table 2
Summary of eight cases of tuberculum sellae meningiomas treated with respected operations (Group B)
No.
Sex
Age
Laterality of tumour
Number of operations
Operative approach
Simpson’s grade
Pathology
26 27 28 29 30 31 32 33
M F F F F F F F
15 44 36 45 35 53 64 30
Bilateral Bilateral Bilateral Bilateral Left Bilateral Bilateral Bilateral
2 2 2 2 2 2 3 4
Bilateral subfrontal Pterional Pterional Pterional Pterional Bilateral subfrontal Bilateral subfrontal Interhemispheric
IV IV IV IV II IV IV IV
Meningothelial Meningothelial Malignant Meningothelial Meningothelial Meningothelial Meningothelial Meningothelial
Postoperative neurological change No change No change Improvement Improvement Improvement Improvement No change No change
Fig. 1 Number of cases by sex in Groups A and B. Fig. 2 Patients’ age and follow-up duration (average) in Groups A and B.
DISCUSSION Tuberculum sellae meningioma is not common, accounting for about 6⬃12% of all intracranial meningiomas.1,2 Suprasellar meningioma often causes visual disturbance and remains undiagnosed until it has enlarged substantially or symptoms have © 2001 Harcourt Publishers Ltd
become aggravated.3 Visual loss is the initial and most common symptom.4–6 About 80% of patients suffer from visual disturbance for a period of between 3 months and 20 years with an average of more than 2 years.4,7,8 Tumours compress the optic chiasma, typically accompanied by bitemporal hemianopsia. In some cases, attachment of the tumour to the lateral part of the planum Journal of Clinical Neuroscience (2001) 8(Supplement 1) 26–31
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Fig. 6 Relationships between operative approaches and Simpson’s grade. Fig. 3 Number of cases in Groups A and B by operative approach.
Fig. 7 Postoperative neurological changes in relation to operative radicality based on Simpson’s grade. Fig. 4 Number of cases in Groups A and B by Simpson’s grade.
Fig. 5 Recurrence rate (%) and years until recurrence by Simpson’s grade.
sphenoidale or tuberculum sellae causes ipsilateral visual loss even if the size is relatively small.5 The unusually long period between the onset of symptoms and final diagnosis is a serious problem, because early diagnosis will increase the chance of a good postoperative visual outcome.4,7 An additional difficulty is that differential diagnosis of the suprasellar mass is still problematic because most patients with tuberculum sellae meningioma present with visual symptoms mimicking a pituitary macroadenoma.4 However an accurate diagnosis is important for the surgical approach, because tuberculum sellae
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meningioma often requires a craniotomy, whereas a transsphenoidal route is preferred for most pituitary macroadenomas.4,9 First of all, the diagnosis must be based on clinical symptoms and signs but preoperative MRI, especially the sagittal view, helps to establish an accurate diagnosis.4 Craniopharyngiomas and pituitary macroadenomas are the most common alternative diagnosis.10 The former can be diagnosed on the basis of the pattern of edema spread on MRI.11 The latter, however, are difficult to differentiate preoperatively from meningiomas despite recent advances in neurodiagnostic imaging. These tumours have no specific radiological features, and therefore several features must be combined to reach the correct diagnosis, mainly based on gadolinium-enhanced, thin section coronal and sagittal MRI.12 The difficulty of removing a tuberculum sellae meningioma totally without damaging optic nerves is well known because it is surrounded by indispensable structures, such as pituitary stalk and gland and the anterior choroidal artery. Various approaches and craniotomies, such as frontobasal interhemispheric and pterional approaches, are popular, but in some cases a trans-sphenoidal approach is used.4,10 Use of an operating microscope reportedly increases the total removal rate while lowering the mortality. Great care is required to separate optic nerves from the tumour to minimise damage to the optic chiasma and avoid damaging the feeding arteries of the optic nerves, especially for cases with longstanding and severe visual disturbance.5,8 Postoperative visual outcome has been reported as unacceptable, especially for large tumours.5 According to previous reports, postoperative visual function improved in about 55%, remained unchanged in 17⬃28%, and worsened in 19⬃25% of the patients.6,8 However, it was also reported that with appropriate preoperative management an excellent visual outcome can be expected,8,10 and that visual symptoms improved in almost all cases without any surgical complications.4,10
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Fig. 8 Preoperative enhanced CT scan (left) and MR image (right) show well-enhanced round mass at tuberculum sellae, slightly deviated to the left.
Fig. 9 Gadolinium-enhanced T1 weighted MR images, sagittal and coronal views. Preoperative MR images (upper) show the well-enhanced mass, compressing the pituitary chiasma from below. Postoperative MR images (lower) show the total resection.
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Fig. 10 Operative view of the illustrative case showed the tumour (arrow) between optic nerves (arrow with broken line) and internal carotid artery (arrow head), compressing them from below. The left optic nerve is pale.
Fig. 11 Pre- (upper) and post- (lower) operative bone window CT scans. (A) shows the optic canals on both sides. (B) is the plane 2 mm higher than the view in (A) and shows the roof of the topic canal. (C) shows the opening of an air sinus (arrow) and (D) clearly shows the unroofing of the optic canal on the left side (arrow head) when compared with (A) and (B).
Surgical outcome is affected by both tumour size and symptom duration.4,13 Patients with a tumour size of 3 cm or less and those with a duration of symptoms of 1 year or less had a better visual outcome, higher total removal rates, lower mortality rates, and lower recurrence rates. When the tumour exceeds 4 cm and compresses
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adjacent neurovascular structure, the possibility of total removal is limited and the chance for visual improvement is low.7,8 The recurrence rates of intracranial meningioma were 11.3% for total resection, and 42.9% and 66.7% for subtotal resection with or without radiation respectively. The overall recurrence rate was
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Fig. 12 Operative view of the illustrative case after total removal of tumour. Pituitary stalk (arrow with dotted line) and unroofed optic canal on the left side can be seen.
19.5%.2 We could not find any reports on the exact recurrence rate of tuberculum sellae meningioma, but it is reasonable to assume it is rather high. Now the situation has changed because of skull base surgery accompanied by microsurgical techniques. Although the surgical procedures for tuberculum sellae meningioma are still difficult, appropriate preoperative imaging and careful intraoperative procedures have made it possible to have both total removal of tumours and an excellent visual outcome.5 Results of our cases reveal that the operation of the better Simpson’s grades (I, II) results in a lower recurrence rate. Because radical removal has no significant effect on the postoperative neurological changes, radical surgery should be undertaken to prevent either recurrence or reoperation. In order to perform a safe operation resulting in a better Simpson’s grade, skull base surgery, such as the fronto-orbitozygomatic approach, will be effective. For example, for a case of meningioma invading an optic canal, the optic canal must be opened positively.14 However, such radical operations sometimes result in unexpected opening of air sinuses following resection of the dural attachment to improve the Simpson’s grade. This injury can be repaired by closing by the pericranial flap with impinging fatty tissues to prevent postoperative CSF leakage.
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CONCLUSIONS
12.
Radical removal of the tuberculum sellae meningiomas resulted in lower recurrence rate without increasing surgical complications. Skull base approaches improved the extent of radical removal of the tuberculum sellae meningioma, and opening of the optic canal helped to improve radicality. Procedures involving the invaded dura and bone were important for achieving total removal of the tuberculum sellae meningioma.
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