Meningiomas: When the Endoscopic Approach Is Better

Fig. 1

Illustrative case: preoperative (a) and postoperative (b) computed tomography (CT) scans; there were no extraocular movement deficits or cosmetic deformities after surgery (c)

Ophthalmological evaluation was negative for oculomotor deficits or visual field impairment.

A lateral transorbital endoscopic approach was performed to remove the tumor completely (Fig. 2).

Fig. 2

Illustrative case: drilling of the tumor with spatula protecting the periorbit (left); removing all the pathologic bone tissue up to the dura mater of the middle cranial fossa (right)

No cranial nerve deficits or cosmetic deformities were observed after the surgery (Fig. 1).

The patient was discharged 3 days after the procedure.

Results

Thirty patients, 22 females (73 %) and 8 males (27 %), suffering from SOM were operated on between 2013 and 2014.

The mean age was 46 years (range, 8–82 years).

Proptosis was the most frequent sign at presentation, with 21 patients suffering from it, 13 in the right eye and 8 in the left eye. Twenty patients had visual impairment, with campimetric defects in 19 and amaurosis in 1. Oculomotor nerve deficits were found in 8 patients, with diplopia in 5. In particular, 4 patients had a deficit of the third cranial nerve; 3, a deficit of the fourth cranial nerve; and 1, a deficit of the sixth cranial nerve. One patient had trigeminal hypoesthesia in V1 and V2.

Traditional transcranial surgery was performed in 23 patients, using a fronto-temporal approach in 19, fronto-temporal orbital approach in 2, and supraorbital approach in 2.

Six patients underwent endoscopic surgery, in four cases by a lateral transorbital approach, in one case by an endonasal approach, and in one case by a combined transorbital and endonasal approach.

A combined transcranial-transorbital endoscopic approach was performed in one patient.

No approach-related mortality or morbidity, such as temporomandibular joint dysfunction or trismus, occurred after the surgery.

Four patients complained of new, but temporary, third cranial nerve paresis in the postoperative period. A new permanent fourth cranial nerve paresis occurred in one patient. No hyperpathic trigeminal sensation appeared after the procedure.

Visual function, as well as proptosis, improved in all patients, remaining stable at 2-year maximum follow-up.

Postoperative neuroradiological evaluation by MRI with gadolinium and bone CT scan on the day after surgery confirmed a gross-total resection in 24 (80 %) patients, with no recurrences after 2 years.

Six patients with residual tumor in the cavernous sinus were considered candidates for gamma-knife radiosurgery.

Discussion

Spheno-orbital meningiomas usually arise from the inner or outer parts of the sphenoid lesser wing, with intraosseous tumor growth, resulting in hyperostosis, and thin soft-tissue growth at the dura [2, 7, 8, 11, 15, 16, 18, 19, 23–25].

Bony tumor growth usually involves the lesser sphenoid wing, the orbital roof, the lateral orbital wall, the superior orbital fissure, the optic canal, and the anterior clinoid process. In cases of orbital extension the growth may occur through the natural canals, such as the optic canal and superior orbital fissure, or the lateral orbital wall [2, 7, 11, 14–16, 18, 23–25].

Soft-tissue growth can spread to extracranial compartments, including the orbital content and the infratemporal fossa with the temporalis muscle.

Dural growth is often widespread, including the basal sphenoid wing, cavernous sinus, and temporal convexity [24].

In most patients, minor symptoms, such as minimal painless proptosis and mild visual impairment, are complained of at presentation. However, cases of loss of vision, severe proptosis, and large cosmetic deformities can be observed [9, 18, 19, 23, 25].

Due to their anatomical, radiological, and morphological aspects, SOMs are considered complex tumors to remove. The involvement of bone, orbit, and neural structures makes the surgery difficult and the resection often incomplete [3–5, 8, 10, 18, 20–22, 24].

However, in cases of visual impairment, oculomotor dysfunction, and severe proptosis, tumor removal is required.

Conversely, a ‘wait and see’ strategy might be appropriate in patients with barely visible proptosis, incidental tumor finding, or little ocular pain.

For years, surgical removal by traditional fronto-temporal and fronto-temporal orbital craniotomy was the gold standard of treatment for SOMs.

Recently, new endoscopic approaches to these tumors have been proposed and have been performed successfully and safely.

The use of endoscopes in orbital surgery was first described in 1981, but their use was limited to the biopsy excision of orbital tumors and to the removal of foreign bodies from the orbit [12, 13].

Even though the endonasal route to approach intraorbital pathologies is increasing in surgical practice, transorbital non-endonasal endoscopic approaches are still little known and used.

In using the endonasal intraorbital approach, a standard spheno-ethmoidectomy has to be performed together with a medial maxillectomy, thus exposing the lamina papyracea. After the lamina papyracea opening, free access to the medial and inferomedial walls of the orbit and, afterwards, to the periorbita, can be obtained [1, 6].

The endoscopic transnasal approach is mainly effective in cases of orbital and optic canal decompression, repair of medial and inferomedial wall fractures, and in intraconal and extraconal lesions with inferomedial location. Accordingly, SOMs located on the medial orbital wall and the inferomedial part of the orbital floor can be removed in this way.

Surgical access to the orbit and periorbital structures through the eyelids and anterior orbital compartment can be achieved through different cutaneous and transconjunctival incisions.

A lateral transorbital approach is performed with an incision on the superior eyelid. The orbital rim is reached by dissection in a superolateral direction. Once the orbital rim is identified and exposed, a careful subperiosteal dissection has to be performed until the superior and inferior orbital fissures are reached [1, 6] (Fig. 3).

Fig. 3

Endoscopic lateral transorbital approach: superior eyelid incision (a), sparing the levator palpebrae aponeurosis (b), identifying the orbital rim (c), and performing a subperiosteal dissection (d)

Only gold members can continue reading. Log In or Register to continue