J.Sales-Llopis

Neurosurgery Department, University General Hospital of Alicante, Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), Alicante, Spain

Suprasellar meningioma usually arises from the tuberculum sellae or the sulcus chiasmatis. Due to the close proximity to the optic apparatus, the same may be involved even when the lesions are small.

They are in a deep and sensitive location, proximity to critical neurovascular elements, hypothalamus with often dense and fibrous nature.

Characteristically lie in a suprasellar subchiasmal midline position, displacing the optic chiasm posteriorly and slightly superiorly, and the optic nerves laterally ¹⁾.

Although tuberculum sellae (TS) and diaphragma sellae meningiomas have different anatomical origins, they are frequently discussed as a single entity.

They comprise approximately 3%–10% of all intracranial meningiomas ²⁾.

The coexistence of a pituitary macroadenoma and a tuberculum sellae meningioma is very rare ³⁾.

In the early 20th century, the first successful surgical removal of a tuberculum sellae meningioma (TSM) was performed and described by Harvey Williams Cushing.

Three distinct anatomical patterns were recognized: exclusively tubercular meningiomas (type A) were accompanied by elongation of the tuberculum-sellar floor interval (TSFI) and, more significantly, of the planum-tuberculum interval (PTI); combined tuberculum sellae (TS) and diaphragma sellae (DS) meningiomas (type B) were associated with relative elongation of both the PTI and TSFI; and the sole exclusively DS meningioma (type C) was associated with elongation of neither PTI nor TSFI.

Suprasellar meningiomas can be classified as tubercular, combined, or diaphragmatic based on preoperative MRI. Exclusively tubercular meningiomas (type A) require only a supradiaphragmatic approach. Tumor involvement of the sellar diaphragm (type B or C) requires resection of the diaphragm and thus a combined infra- and supradiaphragmatic approach ⁴⁾.

Gradual loss of vision is the most common initial complaint by optic nerve compression ^{5) 6) 7) 8) 9)} , and it has been reported that vascular elements may play a significant role in the mechanism of compression ^{10) 11) 12)} Levatin ¹³⁾ was a pioneer in 1961 when he described strangulation of the optic tract by the anterior cerebral artery in a patient harboring a suprasellar tumor. ¹⁴⁾.

Renewed visual deterioration after some initial recovery is highly indicative of tumor recurrence ¹⁵⁾.

In case of pressure on the chiasm, bitemporal filed defects may occur, while in prechiasmal involvement, vision in one eye may be more seriously involved than the other.

Ophthalmological examination include visual acuity, fundoscopy, and visual field.

From ¹⁶⁾

All patients needs evaluation by CT scanning and MR imaging, with intravenous administration of a contrast agent. The radiological parameters include tumor size, brain–tumor interface, peritumoral edema, arterial encasement, optic canal extension, hyperostosis, etc.

Gadolinium-enhanced sagittal and coronal T1 weighted image demonstrating a tuberculum sellae meningioma with suprasellar and sellar involvement.

Angiographic embolization of tuberculum sellae meningiomas is not routinely performed. The vascular supply tends to derive from small perforating branches from the posterior ethmoidal artery, ophthalmic artery, superior hypophyseal artery, and A1/A2 artery segments. Preoperative angiography can help demonstrate distorted vascular anatomy secondary to tumor mass effect, which usually reveals posterior displacement of the A1 and A2 segments of the ACA in 80% of patients and encasement of the A1 segment in 24%

In the early 20th century, the first successful surgical removal of a tuberculum sellae meningioma (TSM) was performed and described by Harvey Cushing. It soon became recognized that TSM pose a formidable challenge for skull base surgeons because of their deep and sensitive location, proximity to critical neurovascular elements, and often dense and fibrous nature. Because of this, over the next several decades controversy transpired regarding their optimal method of resection. Early attempts involved utilization of open transcranial routes. This included classic bilateral and unilateral frontal approaches, followed by pterional or frontotemporal approaches, which have evolved to incorporate skull base modifications, such as the supraorbital, orbitozygomatic, and orbitopterional approaches. Minimally invasive supraorbital keyhole approaches through eyebrow incisions have also been adopted. Over the past 25 years, the microsurgical transsphenoidal approach, classically used for pituitary and parasellar tumors, was modified to resect suprasesllar TSM via the extended transsphenoidal approach. More recently, with the evolution of endoscopic techniques, resection of TSM has been achieved using purely endoscopic endonasal transplanum transtuberculum approaches. Although each of these techniques has been successfully described for the treatment of TSM, the question still remains: is it better to access and operate on these lesions via a traditional, transcranial avenue, or are they better treated via endoscopic endonasal techniques? ¹⁷⁾.

Management ideally consists of gross-total resection without injury to neighboring vital structure. The difficulty in surgically excising a Tuberculum sellae meningioma stems from its relationship to the optic nerves and chiasma and to the anterior cerebral and internal carotid arteries and their perforators, which are frequently encased and/or displaced.

The visual outcome is a matter of concern in surgical treatment. Because the inferior surface of the optic nerve and chiasm receives its blood supply from superior hypophyseal arteries that arise from the supraclinoid segment of the internal carotid artery, surgical dissection of the tumor from the inferior side of the optic apparatus is a more formidable procedure than removal of tumors above the optic apparatus ¹⁸⁾.

Early attempts involved utilization of open transcranial routes. This included classic bilateral and unilateral frontal approaches, followed by pterional or frontotemporal approaches, which have evolved to incorporate skull base modifications, such as the supraorbital, orbitozygomatic, and orbitopterional approaches. Minimally invasive supraorbital keyhole approaches through eyebrow incisions have also been adopted. Over the past 25years, the microsurgical transsphenoidal approach, classically used for pituitary and parasellar tumors, was modified to resect suprasesllar TSM via the extended endoscopic endonasal approach. More recently, with the evolution of endoscopic techniques, resection of TSM has been achieved using purely endoscopic endonasal transplanum transtuberculum approaches. Although each of these techniques has been successfully described for the treatment of TSM, the question still remains: is it better to access and operate on these lesions via a traditional, transcranial avenue, or are they better treated via endoscopic endonasal techniques? ¹⁹⁾.

Complete tumor resection with preservation or improvement of visual function is the goal of tuberculum sellae meningioma (TSM) treatment.

ICA. Internal Carotid Artery

ON. Optic Nerve

Oa. Ophtalmic Artery

rICA. Right Internal Carotid Artery

In 51 patients treated surgically for TSM between 2003 and 2010, with special attention to surgical technique, visual outcomes, and prognostic factors for treatment outcome. All patients were operated via the lateral subfrontal approach. The cohort mean age and Karnofsky performance status (KPS) on admission was 57.1 ± 13.6 and 84.3 ± 11.7, respectively. The most common presenting sign was visual impairment. The mean tumor size was 29.4 ± 10.7 mm. In 45 of the patients (88.2%), gross total resection was achieved. Improvement and/or preservation of visual acuity and visual field were achieved in 95.9% and 85.3%, respectively. Visual functions on admission were found to be the strongest predictors for postoperative improvement in visual outcome, followed by better KPS on admission, smaller tumor size, and young age. Postoperative neurological complications included cerebrospinal fluid (CSF) leak, meningitis, and postoperative seizures. TSM can be safely operated on through the lateral subfrontal approach. A high percentage of complete tumor resection and excellent visual outcomes are achieved using this technique ²⁰⁾.

Can be removed with relatively low morbidity and mortality. Surgical results with this fast and simple approach are similar to those obtained with more extensive, complex, and time-consuming approaches ²¹⁾.

Surgical treatment in the early stage of the disease may result in a better visual outcome. The literature supports transsphenoidal approach for the resection of TSMs with significant optic nerve compromise and limited lateral extension.

Endoscopic transnasal resection may have an equivalent if not superior outcome over transcranial surgery in visual outcome. CSF leaks are still a challenge but may improve with the use of vascularized nasoseptal flaps ²²⁾.

see endoscopic endonasal approach.

Fernandez-Miranda et al present the technical and anatomical nuances needed to perform an endoscopic endonasal removal of a tuberculum sellae meningioma. The patient is a 47-year-old female with headaches and an incidental finding of a small tuberculum sellae meningioma with no vascular encasement, no optic canal invasion, but mild inferior to superior compression of the cisternal segment of the left optic nerve. Neuroophthalmology assessment revealed no visual defects. Treatment options included clinical observation with imaging follow-up studies, radiosurgery, and resection. The patient elected to undergo surgical removal and an endonasal endoscopic approach was the preferred surgical option. Preoperative radiological studies showed the presence of an osseous ring between the left middle and anterior clinoids, the so-called carotico-clinoidal ring. The surgical implications of this finding and its management are illustrated. The surgical anatomy of the suprasellar region is reviewed, including concepts such as the chiasmatic sulcus and limbus sphenoidale, medial and lateral optico-carotid recesses, and the paraclinoidal and supraclinoidal segments of the internal carotid artery. Emphasis is made in the importance of exposing the distal dural ring of the internal carotid artery and the precanalicular segment of the optic nerve for adequate intradural dissection. The endonasal route allows for early coagulation of the tumor meningeal supply and extensive resection of dural attachments, and importantly, provides an inferior to superior access to the infrachiasmatic region that facilitates complete tumor removal without any manipulation of the optic nerve. The lateral limit of dural removal is formed by the distal dural ring, which is gently coagulated after the tumor is resected. A 45° scope is used to inspect for any residual tumor, in particular at the entrance of the optic nerve into the optic canal and at the most anterior margin of the exposure (limbus sphenoidale). The steps for reconstruction are detailed and include intradural placement of dural substitute and extradural placement of the nasoseptal flap. The nuances for proper harvesting, positioning, and reinforcement of the flap are described. No lumbar drain was used. The patient had an uneventful recovery with no CSF leak or any other complications. Imaging follow-up at 6 months showed complete removal of the tumor. The patient had no sinonasal or neurological symptoms, and olfaction was fully preserved. The video can be found here: http://youtu.be/kkuV-yyEHMg ²³⁾.

Recent reports of surgical resection of tuberculum sellae meningiomas through an endoscopic endonasal approach (EEA) have provided an alternative to transcranial approaches in selected cases. However, these published reports have been limited by small sample size from single institutions.

A systematic review of the literature and analyzed pooled data for descriptive statistics on short-term morbidity and outcomes, compared EEA to transcranial approaches reported during the same time-frame. Six studies (49 patients) met inclusion criteria for EEA. A pooled analysis of transcranial results reported during a similar time period yielded 11 studies (412 patients). There were no differences in rate of gross total resection or peri-operative complications between the two groups. Although the EEA group was associated with higher rates of CSF leak (p < 0.05; OR 3.9; 95 % CI 1.15, 15.75), EEA were also associated with significantly higher rates of post-operative visual improvement compared to transcranial approaches (p < 0.05; OR 1.5; 95 % CI 1.18, 1.82). A systematic review of the small series of EEA for tuberculum sellae meningiomas published to date revealed similar extent of resection and morbidity, but increased post-operative visual improvement compared to transcranial approaches during a similar time period. Long-term follow-up will be needed to define recurrence rates of EEA as compared to transcranial approaches. Cautious use of EEA for the removal of smaller tuberculum sellae meningiomas after formal endoscopic training may be warranted ²⁴⁾.

The internal carotid artery (ICA) and the patent cavernous sinus were detected with the indocyanine green (ICG) endoscope in real time and at high resolution. The ICG endoscope is very useful Hide et al. suggest that the real-time observation of the blood supply to the optic nerves and pituitary helps to predict the preservation of their function ²⁵⁾.

During the macrosurgical era, visual improvement varied between 40% and 63% ^{26) 27) 28)}.

The range of improvement rates in microsurgical series is 25%–80% ^{29) 30) 31) 32) 33) 34)}.

In the series of Seol et al., seventy-four of 86 patients (86 %) underwent total removal of the tumor. In three of these cases (3.4 %), recurrence developed. Thirty patients were classified into the “Excellent” group, 21 into the “Good” group, 20 into the “Fair” group, and 15 into the “Poor” group. In multivariate analysis, adhesion to optic nerve was an independent and significant predictor of clinical outcome. Favorable visual outcomes in both short- and long-term postoperative periods were achieved in 80.8 % of cases. Preoperative and short-term visual outcomes were closely related to long-term visual outcome. Six of eight patients with preoperative CF status showed reversibility to a serviceable status after surgery. However, there was no conversion to serviceable status from no perception of light (NPL), to hand movement (HM) ³⁵⁾.