07-MARCH-2004  BAYAN MANSOUR MAHMOUD SUKKAR  LEFT GIANT OLFACTORY GROOVE MENINGIOMA  WITH MISSED PREVIOUS LEFT HUGE OCCIPITO-PARIETAL  EXTRADURAL HEMATOMA.

Anamnesis

	The patient came to the clinic 25-February-2004 complaining of severe headache for several months and blurred vision lat month with anosmia.
	MRI brain with  contrast done 14-February-2004 showing huge olfactory groove meningioma more to the left with massive edema over the left cerebral hemisphere.
	On examination: The patient has anosmia with decreased visual functions more the left eye with scatomas. She had episodes of vomiting the last 2 weeks. The patient has epiattacks and she felt down in the bathroom one week ago.
	Modified left bifrontal craniotomy done with reflection of the bone flap to the left ear. The brain is severely swollen and all measures to decrease the swelling failed. Trying to minimize the traction injury, the tumor was approached and piece-meal resection was achieved. Total resection of the mass was done, but the brain swelling persisted. The wound was closed, so that the dura was not pushing the brain. The patient was extubated and sent to the ICU. The patient still drowsy and she was sent for control CT-scan of the brain, which revealed very huge occipital hematoma. The patient was taken to the operating room and the hematoma was evacuated, after what good recovery was achieved.

FOLLOW UP

	The patient had huge extradural hematoma, which was the cause of the swelling and made the first operation difficult. Usually after resection of the tumor. the brain  becoming lax and regain good pulsation, but here was not the case.
	In retrospective analysis, the hematoma must be diagnosed first and removed and then remove the tumor. But for several reasons the hematoma was missed and the first surgery was very difficult.
	In the future do the MRI investigations immediately before surgery.
	The patient came to the clinic 09-April-2007 to discontinue Epanutin. She is convulsion free for three years. On examination, the right eye still having decreased vision with bilateral anosmia.

OLFACTORY GROOVE MENINGIOMAS

Clinical Features
These tumors arise from the midline of the anterior fossa between the crista Galli and the tuberculum sella. They are usually bilateral but may be asymmetric and attain a large size before causing symptoms. The most common presenting symptom is a subtle change in mental function or headache alone or in combination with mental function change, but a disturbance in vision or a seizure disorder may also be the initial manifestation. Loss of the sense of smell was recorded as "possibly" the primary symptom in only 3 of 28 patients in Cushing's series, and he questioned the reliability of this finding.
MRI clearly defines the extent of the tumor, the edema in the surrounding brain, the relationship of the tumor to the optic nerves and anterior cerebral arteries, and any extension into the ethmoid sinus. Angiography is rarely needed.
Surgical Management
In planning the operation, it is important to remember that the blood supply comes into the tumor through the bone in the midline of the anterior fossa from branches of the ethmoidal, middle meningeal, and ophthalmic arteries; the posterior capsules may be attached to the optic nerves, chiasm, and anterior cerebral arteries. For patients with a large tumor, It is preferable to perform a bifrontal craniotomy. This approach is associated with the least amount of retraction on the frontal lobes, gives direct access to all sides of the tumor, and allows the surgeon to decompress the tumor while working along the base of the skull to interrupt the blood supply. For smaller tumors, a right subfrontal approach coming from laterally over the orbital roof, as for tuberculum sella meningioma, may be used. Some uses a pterional approach. Others use either exposure and may resects part of the frontal lobe. The patient is placed carefully in the supine position with the head elevated and slightly extended. Using a coronal incision, the skin flap and underlying tissue, including pericranial tissue, are turned down together. Burr holes are placed just below the end of the anterior temporal line and on each side of the saggital sinus at the level of the skin incision. The cut just above the supraorbital ridge is made from each side as far medially as possible. Usually this leaves a centimeter or less of bone in the midline. Because of the irregular bone projecting from the inner table of the skull in this area, it is often not possible to cut completely across the area, but the external table can be cut with a fine drill attachment and the bone can be broken at this point. The frontal sinuses are almost always entered. The mucosa is removed and the sinuses are packed with bacitracin-soaked Gelfoam. A flap of pericranial tissue from the back of the skin flap is turned down over the sinuses and sewn to the adjacent dura. The dural incision is made over each medial inferior frontal lobe just above the edge of the craniotomy opening. While the frontal lobes are retracted carefully, the superior sagittal sinus is divided between two silk sutures and the falx is cut. The frontal lobes are then retracted carefully laterally and slightly posteriorly. The tumor will come into view in the midline; at times it is found to have grown into the region of the crista galli and falx. The anterior capsule of the tumor is exposed, and then an extensive internal decompression is done. The base of the tumor in the midline is gradually divided, interrupting the blood supply that is coming in through numerous openings in the bone. These are occluded with coagulation and bone wax. The capsule can now be reflected into the area of the decompression without undue pressure on the frontal lobes. Great care is taken during the dissection of the posterior portion of the capsule. The surgeon reflects it anteriorly and is careful to look for the pericallosal branch of each anterior cerebral artery. The frontal polar branch will often be adherent to the tumor and may need to be divided. It is usually possible to follow the capsule back to the sphenoid wing and then, working medially, to identify the anterior clinoid processes and the optic nerves. At times it may be difficult to see the nerves because of the posterior and inferior compression and the thickened arachnoid. However, under magnification, the tumor can be reflected off the optic nerve(s). Once the bulk of the tumor is removed, the dural attachment is totally excised and any bone hyperostosis removed, with care taken to avoid entering the ethmoid sinus unless it is known that the tumor extends into the sinus. The region of the cribriform plate is covered with a graft of pericranial tissue and Gelfoam to prevent a cerebrospinal fluid (CSF) leak.
Results
Complete removal can be achieved in 90% of cases and 5% with a radical subtotal removal with a small fragment left on the internal carotid artery or other vitally important structures. In 90% of patients a good result can be achieved. Postoperative death due to various causes is around 5%.
The incidence of complications is low and do not interfere with eventual recovery. CSF leak through the ethmoid sinus that required transethmoidal repair can be in 5% of cases. A wound infection also 5%, A subdural hygroma requiring a subdural-peritoneal shunt in 5%. Disturbance in mental function and personality changes when present preoperatively or transiently in the postoperative period usually recover completely. Preoperative visual symptoms usually recover and headache is relieved.
Background
A systematic investigation of long-term follow-up results after microsurgical treatment of patients harbouring an olfactory groove meningioma, particularly with regard to postoperative olfactory and mental function, has rarely been performed. We reassessed a series of patients treated microsurgically for an olfactory groove meningioma in regard to clinical presentation, surgical approaches and long-term functional outcome. Method. Clinical, radiological and surgical data in a consecutive series of 56 patients suffering from olfactory groove meningioma were retrospectively reviewed.
Findings. Presenting symptoms of the 41 women and 15 men (mean age 51 years) were mental changes in 39.3%, visual impairment in 16.1% and anosmia in 14.3% of the patients. Preoperative neurological examination revealed deficits in olfaction in 71.7%, mental disturbances in 55.4% and reduced vision in 21.4% of the cases. The tumour was resected via a bifrontal craniotomy in 36, a pterional route in 13, a unilateral frontal approach in 4 and via a supraorbital approach in 3 patients. Extent of tumour resection according to Simpson’s classification system was grade I in 42.9% and grade II in 57.1% of the cases. After a mean followup period of 5.6 years (range 1–13 years) by clinical examination and magnetic resonance imaging (MRI), 86.8% of the patients resumed normal life activity. Olfaction was preserved in 24.4% of patients in whom pre- and postoperative data were available. Mental and visual disturbances improved in 88 and 83.3% of cases, respectively. Five recurrences (8.9%) were observed and had to be reoperated.

Conclusions
Frontal approaches allowed better resection of tumours with gross infiltration of the anterior cranial base, tumours extending into the ethmoids or nasal cavity and in cases with deep olfactory grooves. Preservation of olfaction should be attempted in patients with normal or reduced smelling preoperatively.
Introduction
Meningiomas of the midline anterior skull base include tumours originating from the dura of the cribriform plate, planum sphenoidale and tuberculum sellae and account for about 10% of all intracranial meningiomas [41]. For clinical, radiological and surgical purposes true olfactory groove meningiomas, i.e. tumours originating from the dura between the crista galli and the frontosphenoid suture should be differentiated from planum sphenoidale and tuberculum sellae meningiomas [8, 32]. Tumours arising from the latter sites usually come to clinical attention at an early stage with visual deterioration, while this is a late feature in olfactory groove meningiomas which usually remain clinically quiescent during the early phase of growth. Anatomically, olfactory groove meningiomas arise from the weakest part of the skull base, the cribriform plate, which makes them prone to infiltrate the underlying bone and extend into the paranasal sinuses and nasal cavity. This is a rare feature in planum sphenoidale or tuberculum sellae meningiomas.
A systematic assessment of functional outcome after resection of olfactory groove meningiomas, particularly in respect to olfactory function, has rarely been performed [3, 30, 46]. We retrospectively analyzed meningiomas with a predominant origin from the dura of the cribriform plate with regard to clinical presentation, different surgical approaches and follow-up results which were treated microsurgically in our institution.
Patients and methods
From June 1990 till June 2003, an olfactory groove meningioma was microsurgically resected in 56 consecutive patients in our department. The medical charts, surgical records and radiological studies were retrospectively reviewed in these patients. Only tumours with a primary origin from the dura of the cribriform plate were included in this report. Lesions with a predominant dural origin from the planum sphenoidale, tuberculum sellae, anterior clinoidal process or orbital roof were not considered in this series.
Radiological studies
Magnetic resonance imaging (MRI) was obtained preoperatively in all patients and clearly demonstrated the relationship of the tumour with the optic nerves, chiasm and the anterior cerebral arteries (ACA). These vessels were encased by the tumour in three patients. A significant bifrontal or unilateral edema was displayed on MRI in 34 patients. CT with bone algorithms, performed preoperatively in 23 patients revealed a hyperostosis of the crista galli or the cribriform plate in six and erosion of the cribriform plate in four cases. Cerebral angiography was performed regularly early in the study period to demonstrate tumour vascularity, provide information regarding ACA displacement and to evaluate the possibility of preoperative embolization. In all 23 cases studied angiographically, the tumour was predominantly supplied by the anterior or posterior ethmoidal branches of the ophthalmic artery and preoperative partial embolization was performed in two patients with occlusion of the anterior branch of the middle meningeal artery. Angiography is no longer performed in these tumours in our institution. Mean maximal diameter of the tumours as depicted from preoperative MRI was 5.2 cm (range: 2.5–7.5 cm).
Tumour extension and dural attachment
As shown by preoperative MRI and confirmed intraoperatively, the tumour was attached to the cribriform plate, adjoining part of the planum sphenoidale, crista galli and medial orbital roofs on both sides in 24 patients. Tumours in these cases were broad-based, were larger than 5.5 cm in maximal diameter and had an almost symmetric growth on both sides. The tumour attachment area was restricted to the cribriform plate and adjacent part of the orbital roofs on both sides in 19 patients.
A pure unilateral dural origin from the cribriform plate and adjoining anterior cranial base was observed in 13 patients, on the left side in six and on the right side in seven cases. Bilateral extension of the tumour into the ethmoidal cells was disclosed on preoperative coronal MRI in two cases and unilateral extension in one. The tumour reached the nasal cavity in two additional cases. The meningioma extended into the optic canal on one or both sides in five patients, all of whom had visual disturbances preoperatively.
Surgical approaches
Thirty-six patients with a bilateral tumour were operated via a bifrontal craniotomy with opening of the frontal sinus, double ligation and division of the anterior end of the superior sagittal sinus with subsequent subfrontal Fig. 3. Artist’s sketch showing dural attachment of olfactory groove meningiomas. (A) Bilateral attachment to the cribriform plate, planum sphenoidale and orbital roofs (24 cases), (B) tumours attached to the cribriform plate and medial orbital roofs bilaterally (19 cases), (C) Unilateral attachment to the cribriform plate and medial orbital roof (13 cases). Posterior extension over the tuberculum sellae (straight arrow) was observed in four, encroachment into the optic canal (curved arrow) in five cases removal of the meningioma. This approach has been described in detail [27, 28, 36]. Additionally, a bilateral tumour was extirpated via a pterional approach in seven patients. The contralateral tumour part was removed after partial resection of the falx cerebri and crista galli [15, 47]. Tumours restricted to one side were resected through a unilateral frontal approach in four cases, via a pterional approach in six and a lateral supraorbital (‘key-hole’) craniotomy in three patients [35]. The latter approach was used in small tumours up to 3.5 cm in diameter and was endoscopically-assisted in one case with a deep olfactory groove. In all but three patients were the tumour had been removed via a frontal craniotomy the floor of the anterior cranial base was covered with a vascularized galea-periosteal flap reinforced with sutures and fibrin glue. A hyperostosis of the crista galli and, or cribriform plate was removed by drilling in 16 patients. Tumours that had invaded into the ethmoidals or nasal cavity were removed via a bifrontal craniotomy. This was combined with a lateral rhinotomy performed by members of the otolaryngology department in two cases.
Patient’s follow-up
All patients were followed-up with clinical examination and MRI studies six months and one year after surgery. Thereafter, patients were re-examined at one or two year intervals based on each follow-up result. Postoperative assessment of mental function was available in 25 of 31 patients with preoperative personality changes. Olfactory function was tested semi-quantitatively before surgery and on each follow-up examination with different odours for each nostril separately. Preoperatively, test results were reliably obtained in 46 patients. In the remainder mental changes allowed only a gross differentiation between smelling and not smelling at best. Postoperative results of olfactory tests were available for analysis in 41 patients. All patients with visual disturbances had detailed pre- and postoperative ophthalmological investigations, including visual acuity, visual fields, fundoscopy and intraocular pressure measurement.
Results
The 41 women and 15 men had a mean age of 51 years (range 30–74 years). The most common presenting symptoms were mental disturbances in 22 patients (39.3%), headache in 11 (19.6%), visual deterioration in nine (16.1%) and anosmia in eight cases (14.3%).

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Comments

	Intraoperative navigation will ameliorate such events, and confirm the necessity for such technology. Real-time intraoperative navigation is costly and commercially inapplicable for private sector, and must be modified to be used for all surgical disciplines and to have neurophysiologic monitoring added to the navigation system merged with the visual data in real time.
	MRI of the brain done 01-January-2005 confirming the total resection of the tumor with mild malacia of the left frontal lobe due to to pressure effect of the missed right occipito-parietal extradural hematoma.

Postoperative MRI after 3 years showing complete resection and no recurrence.

Olfactory groove meningiomas: functional outcome
in a series treated microsurgically
H. Bassiouni, S. Asgari, and D. Stolke
Department of Neurosurgery, University Hospital Essen, Essen, Germany

	Background A systematic investigation of long-term follow-up results after microsurgical treatment of patients harbouring an olfactory groove meningioma, particularly with regard to postoperative olfactory and mental function, has rarely been performed. We reassessed a series of patients treated microsurgically for an olfactory groove meningioma in regard to clinical presentation, surgical approaches and long-term functional outcome. Method. Clinical, radiological and surgical data in a consecutive series of 56 patients suffering from olfactory groove meningioma were retrospectively reviewed. Findings. Presenting symptoms of the 41 women and 15 men (mean age 51 years) were mental changes in 39.3%, visual impairment in 16.1% and anosmia in 14.3% of the patients. Preoperative neurological examination revealed deficits in olfaction in 71.7%, mental disturbances in 55.4% and reduced vision in 21.4% of the cases. The tumour was resected via a bifrontal craniotomy in 36, a pterional route in 13, a unilateral frontal approach in 4 and via a supraorbital approach in 3 patients. Extent of tumour resection according to Simpson’s classification system was grade I in 42.9% and grade II in 57.1% of the cases. After a mean followup period of 5.6 years (range 1–13 years) by clinical examination and magnetic resonance imaging (MRI), 86.8% of the patients resumed normal life activity. Olfaction was preserved in 24.4% of patients in whom pre- and postoperative data were available. Mental and visual disturbances improved in 88 and 83.3% of cases, respectively. Five recurrences (8.9%) were observed and had to be reoperated.
	Conclusions Frontal approaches allowed better resection of tumours with gross infiltration of the anterior cranial base, tumours extending into the ethmoids or nasal cavity and in cases with deep olfactory grooves. Preservation of olfaction should be attempted in patients with normal or reduced smelling preoperatively.
	Introduction Meningiomas of the midline anterior skull base include tumours originating from the dura of the cribriform plate, planum sphenoidale and tuberculum sellae and account for about 10% of all intracranial meningiomas [41]. For clinical, radiological and surgical purposes true olfactory groove meningiomas, i.e. tumours originating from the dura between the crista galli and the frontosphenoid suture should be differentiated from planum sphenoidale and tuberculum sellae meningiomas [8, 32]. Tumours arising from the latter sites usually come to clinical attention at an early stage with visual deterioration, while this is a late feature in olfactory groove meningiomas which usually remain clinically quiescent during the early phase of growth. Anatomically, olfactory groove meningiomas arise from the weakest part of the skull base, the cribriform plate, which makes them prone to infiltrate the underlying bone and extend into the paranasal sinuses and nasal cavity. This is a rare feature in planum sphenoidale or tuberculum sellae meningiomas. A systematic assessment of functional outcome after resection of olfactory groove meningiomas, particularly in respect to olfactory function, has rarely been performed [3, 30, 46]. We retrospectively analysed meningiomas with a predominant origin from the dura of the cribriform plate with regard to clinical presentation, different surgical approaches and follow-up results which were treated microsurgically in our institution.
	Patients and methods From June 1990 till June 2003, an olfactory groove meningioma was microsurgically resected in 56 consecutive patients in our department. The medical charts, surgical records and radiological studies were retrospectively reviewed in these patients. Only tumours with a primary origin from the dura of the cribriform plate were included in this report. Lesions with a predominant dural origin from the planum sphenoidale, tuberculum sellae, anterior clinoidal process or orbital roof were not considered in this series.