Identification of the internal carotid artery at the superior part of the cavernous sinus during endoscopic endonasal cavernous sinus tumor surgery

Pituitary adenoma with posterior area invasion of cavernous sinus: surgical anatomy, approach, and outcomes

We found a series of Knosp grade 3A-4 pituitary adenomas in the posterior areas of the cavernous sinus (CS), a triangular-like structure on axial MRI. In this study, we dissected the surrounding neurovascular structure, discussed the surgical approach, and analyzed outcomes for patients with this invasion into this area. Eight embalmed adult cadaveric specimens were prepared for this study to demonstrate in detail the surgical anatomy related to this triangular-like structure. We used the "two points and one line" method to determine the surgical approach, and 35 cases with this area invasion were retrospectively reviewed. According to the endoscopic and microsurgical anatomy, the triangular-like structure appearing on the axial MRI is correlated with a square-based pyramid structure in the CS, and the upper surface is the posterior portion of the oculomotor triangle. A total of 37 posterior areas of the CS were involved in 35 patients. The accuracy of the "two points and one line" method in predicting the surgical approach is 86.5% (32/37). All three patients with Knosp 3A underwent gross total resection (GTR). Twenty (62.5%) patients with Knosp 4 underwent GTR, 9 (28.1%) patients underwent subtotal resection, and 3 (9.4%) patients underwent partial resection. Preoperative symptoms were alleviated to varying degrees, and no worsening occurred. Postoperative complications included two (5.7%) cases of cerebrospinal fluid leakage, one (2.9%) case of meningitis, two (5.7%) cases of permanent diabetes insipidus, and three (8.6%) cases of transient cranial nerve palsy. The "two points and one line" method is of great value in predicting the surgical approach of pituitary adenomas with CS invasion. The anatomic description of this particular square-based pyramid structure in the CS refines the understanding of pituitary adenomas with CS invasion.

Endoscopic extradural supraorbital approach to the temporal pole and adjacent area: technical note

The authors’ initial experience with the endoscopic extradural supraorbital approach to the temporal pole and adjacent area is reported. Fully endoscopic surgery using the extradural space via a supraorbital keyhole was performed for tumors in or around the temporal pole, including temporal pole cavernous angioma, sphenoid ridge meningioma, and cavernous sinus pituitary adenoma, mainly using 4-mm, 0° and 30° endoscopes and single-shaft instruments. After making a supraorbital keyhole, a 4-mm, 30° endoscope was advanced into the extradural space of the anterior cranial fossa during lifting of the dura mater. Following identification of the sphenoid ridge, orbital roof, and anterior clinoid process, the bone lateral to the orbital roof was drilled off until the dura mater of the anterior aspect of the temporal lobe was exposed. The dura mater of the temporal lobe was incised and opened, exposing the temporal pole under a 4-mm, 0° endoscope. Tumors in or around the temporal pole were safely removed under a superb view through the extradural corridor. The endoscopic extradural supraorbital approach was technically feasible and safe. The anterior trajectory to the temporal pole using the extradural space under endoscopy provided excellent visibility, allowing minimally invasive surgery. Further surgical experience and development of specialized instruments would promote this approach as an alternative surgical option.

Endoscopic Endonasal Surgery for Tumors of the Cavernous Sinus: A Series of 234 Patients

BACKGROUND

Cavernous sinus (CS) tumors often are considered inoperable. We present our experience with endoscopic endonasal surgery (EES) and compare the outcomes for different tumor.

METHODS

EES (medial or lateral approach) was used in 234 patients with CS tumors. The cohort included 175 (75%) pituitary adenomas and 59 (25%) nonadenomatous lesions.

RESULTS

Presenting symptoms were significantly different between the 2 groups, with cranial neuropathies occurring mainly in nonadenomas (P < 0.0001). The overall gross total tumor resection rate from the CS was 37.3% (37.1% in adenomas, 38.1% in non-adenomas). In total, preexisting cranial nerve (CN) dysfunction improved in 56.4% of the patients. After treatment completion (including radiation of residual tumor), 83.3% of acromegalic patients, 50% of prolactinomas and 33.3% of Cushing's disease, were in remission. Visual loss improved in 86.8% of adenomas and in 70.8% of nonadenomas. Intracavernous CN palsies improved in 77.3% of adenomas and 42.4% of nonadenomas. New permanent CN palsies occurred in 7 nonadenomas, which is significantly greater than in adenomas (P = 0.007). The leak rate of cerebrospinal fluid was 6.3% for adenomas and 11.9% for nonadenomas. Four patients suffered an internal carotid artery injury with no neurologic sequelae in 3 cases and 1 death (0.4%).

CONCLUSIONS

EES provides an easily accessible midline corridor to the CS with equivalent or superior results to transcranial approaches in the management of select tumors. Symptomatology due to CS invasion is more likely to improve in pituitary adenomas and the rate of surgical complications is greater in nonadenomas. Using a team approach, the overall mortality due to vascular injury is low.

Endoscopic endonasal approach to the middle cranial fossa through the cavernous sinus triangles: anatomical considerations

The lateral limit of endoscopic endonasal surgery has yet to be defined. The aim of this study was to investigate the lateral limit of endoscopic endonasal surgery at the level of the sphenoid sinus. Access from the sphenoid sinus to the middle cranial fossa through the cavernous sinus triangles was evaluated by cadaver dissection. Anatomical analysis demonstrated that the medial temporal dura mater was exposed through the anterior area of the clinoidal triangle, anteromedial triangle, and superior area of the anterolateral triangle, indicating potential corridors to the middle cranial fossa. This study suggests that the cavernous sinus triangles are applicable in selected cases to manage middle cranial fossa lesions by endoscopic endonasal surgery.