June 23, 2021

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Can tuberosity sellar meningioma cause blindness?

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Can tuberosity sellar meningioma cause blindness?



Can tuberosity sellar meningioma cause blindness?  Cushing completed the first total resection of tuberosity sellar meningioma in 1916, but he did not report it until 1929. Day published the results of the first 8 surgical resections in 1922. In 1938, Cushing and Eisengard reported 28 cases of sellar tuber meningioma, and proposed a four-stage classification method based on tumor size.

Can tuberosity sellar meningioma cause blindness?

In the most frequently cited article by Cushing and Eisenhardt, they used the term “saddle” to describe tumors that originated from the dura mater of the sella nodules. This term caused a lot of confusion in the literature, because later publications will originate from several different tumors, such as the anterior clinoid process, optic nerve foramen, olfactory sulcus, and sphenoid platform. within. We believe that in the vast majority of cases, tuberosity sellar meningioma should and can be distinguished from other meningiomas called ‘saddle’.

 

The tuberosity of sella is the slightly raised bone in front of the pituitary fossa, and its height and width are only a few millimeters. Tumors originating from this area usually have a diameter of 2 to 4 cm when they cause clinical symptoms. Because the volume of the sellar area is relatively small, the attachment of these tumors on the dura can extend forward to the anterior border of the sphenoid bone (the front border of the cross anterior cistern), and can involve the saddle septum and funnel backward.

There is no value in further classification of tumors in this area, because as the tumor continues to grow, the optic nerve and optic chiasm will be lifted, resulting in the same clinical manifestations. Although we recognize that the origin of tumors under the microscope is either the sellar tubercle or the sellar septum, we still call these tumors sellar tubercle meningioma.

Sellar tuber meningioma is one of the common benign tumors in this area, accounting for 5% to 10% of intracranial meningiomas. The clinical manifestations are mainly as the tumor invades the optic nerve or optic chiasm caused by visual field disturbance, generally first manifested as unilateral The vision was impaired, and the visual field of both sides decreased. Unilateral vision loss accounts for 50%, binocular vision loss accounts for 55%, and fundus examination reveals primary optic atrophy.

Headache is another common symptom of this disease. A few can be manifested as mental disorders, such as lethargy and memory decline, which may be related to tumor compression on the underside of the frontal lobe. A very small number of patients may present endocrine dysfunction of pituitary tumors, such as loss of libido, amenorrhea, etc., which may cause endocrine dysfunction due to tumor compression of the pituitary.

Cushing and Eisenhart divided the sella tuber meningioma into four stages (1) early stage, (2) asymptomatic stage, (3) suitable for surgery, and (4) late or inoperable stage. They not only regarded the sella tuber meningioma as a characteristic disease, but also emphasized the importance of the relationship between tumor growth and the visual organs and the possibility of surgical resection. The introduction of operating microscopes allows neurosurgeons to better understand the relationship between tumors and surrounding structures.

 

 

Selection of treatment strategies for tuberosity sellar meningiomas

Although meningiomas may invade bone and cause bone hyperplasia, they mainly grow in the subdural space and remain outside the arachnoid. With the growth of tuberosity sellar meningioma, the arachnoid membrane at the bottom of the crossing pool was pushed and covered the surface of the tumor. As the tumor continues to grow, the tumor invades the adjacent brain cistern and is involved in different levels of the arachnoid membrane.

The arachnoid cistern wall provides a natural barrier between the tumor and the arteries and nerves that travel through the subarachnoid space. Patient selection and treatment strategy The best treatment method for tuberosity sella meningioma is: if possible, remove all the tumor, including the dura mater and the affected bone. It is not recommended to treat traditional radiotherapy and stereotactic radiotherapy as the first treatment.

For those recurrent tumors or residual tumors that cannot be removed by surgery, or elderly patients and physically weak patients, radiotherapy can be used as an adjuvant treatment. Preoperative embolization is not feasible because the arterial blood supply of the tumor comes from the internal carotid artery circulation, and the internal carotid artery communicates with the ophthalmic artery.

 

These tumors can be surgically removed from three craniotomy approaches: coronary, single frontal, and pterional approaches. Advocates of the subfrontal approach believe that it provides the greatest degree of exposure to the saddle area. The disadvantage is that after the olfactory nerve is damaged and the frontal sinus is opened, there is the possibility of potential infection and cerebrospinal fluid leakage.

It has been suggested to remove the supraorbital arch in the subfrontal pathway to obtain the optimal exposure of the sella. We removed the tumor of the sellar tuberosity through the pterional approach. This approach does not endanger the olfactory nerve, nor does it allow the patient to bear the risk of cerebrospinal fluid leakage or infection after the opening of the frontal sinus. Compared with the subfrontal approach, the pterion approach involves extensively removing the sphenoid crest and fully dissecting the scoliosis. It only takes a small amount of traction on the brain to reach the supra-saddle.

The only disadvantage is that the swelling of the ipsilateral optic nerve and below the optic chiasm is not as clear as the subfrontal approach. This small disadvantage does not prove that it is reasonable to allow patients to bear the risks and complications of coronary craniotomy and loss of sense of smell. The craniotomy is usually done on the side of the non-dominant hemisphere. If the tumor grows abnormally between the optic nerve and the internal carotid artery, then we choose to remove the lesion from this side approach. This approach can obtain the best surgical exposure, and at the same time, there is not too much damage to the optic nerve or internal carotid artery. If one eye is blind, the approach is to choose the side of the amblyopia, because this method can provide the best exposure for the decompression of the optic nerve on the lighter side.

 

There are many surgical approaches for tuberosity sellar meningioma, and any approach has no absolute advantage. The choice of surgical approach is closely related to the growth mode of the tumor, the relationship between the surrounding tissues, and the type and grade of the tumor. Before surgery, it is necessary to comprehensively consider the surgical situation and possible complications after surgery, and determine the operation method according to the specific situation. However, it is necessary to have a detailed grasp of the anatomy of the saddle and cope with the complications that may occur after the operation.

 

 

 

 

(source:internet, reference only)


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