Edinson Najera

Endoscopic Endonasal Approach for Complex Macroadenoma with Suprasellar and Retrochiasmatic Extension

In this video, we describe the technical nuances of an endoscopic endonasal approach (EEA) for a complex macroadenoma with suprasellar and retrochiasmatic extension. The patient is a 51-year-old male with several years history of progressive visual loss. Neuro-ophthalmology assessment revealed a profound visual loss with homonymous hemianopsia and left optic nerve atrophy. His pituitary hormonal profile was normal. The options for surgical approach included transcranial, endoscopic endonasal, or a combination of both. An EEA was the preferred surgical option, because it allows for early identification of the pituitary gland, and provides access to the suprasellar region including pre- and retrochiasmatic spaces, which facilitates tumor removal while minimizing manipulation of the optic apparatus. While most pituitary adenomas do not require extracapsular subarachnoidal dissection, there are complex adenomas with subarachnoidal invasion and multilobulated morphology, such as the one presented here, that require a combination of internal debulking, extracapsular and subarachnoidal dissection. The technique presented here allows for complete tumor resection, avoiding the risk of postoperative apoplexy of residual adenoma, and facilitates identification of perforating branches and neural structures that require meticulous preservation. Here, we also illustrate the proper management of reconstruction-related complications. Postoperative course was complicated with meningitis with necrotic nasoseptal flap and required surgical debridement, new inferior turbinate flap, fascia lata, lumbar drain, and 6-week antibiotic treatment. Imaging follow-up showed complete removal of tumor. The patient had significant improvement in visual fields and left visual acuity, and no postoperative hormonal dysfunction. The link to the video can be found at: https://youtu.be/9T5b167bVJA .

The medial wall of the cavernous sinus. Part 1: Surgical anatomy, ligaments, and surgical technique for its mobilization and/or resection

OBJECTIVEThe medial wall of the cavernous sinus (CS) is often invaded by pituitary adenomas. Surgical mobilization and/or removal of the medial wall remains a challenge.METHODSEndoscopic endonasal dissection was performed in 20 human cadaver heads. The configuration of the medial wall, its relationship to the internal carotid artery (ICA), and the ligamentous connections in between them were investigated in 40 CSs.RESULTSThe medial wall of the CS was confirmed to be an intact single layer of dura that is distinct from the capsule of the pituitary gland and the periosteal layer that forms the anterior wall of the CS. In 32.5% of hemispheres, the medial wall was indented by and/or well adhered to the cavernous ICA. The authors identified multiple ligamentous fibers that anchored the medial wall to other walls of the CS and/or to specific ICA segments. These parasellar ligaments were classified into 4 groups: 1) caroticoclinoid ligament, spanning from the medial wall and the middle clinoid toward the clinoid ICA segment and anterior clinoid process; 2) superior parasellar ligament, connecting the medial wall to the horizontal cavernous ICA and/or lateral wall of the CS; 3) inferior parasellar ligament, bridging the medial wall to the anterior wall of the CS or anterior surface of the short vertical segment of the cavernous ICA; and 4) posterior parasellar ligament, which anchors the medial wall to the short vertical segment of the cavernous ICA and/or the posterior carotid sulcus. The caroticoclinoid ligament and inferior parasellar ligament were present in most CSs (97.7% and 95%, respectively), while the superior and posterior parasellar ligaments were identified in approximately half of the CSs (57.5% and 45%, respectively). The caroticoclinoid ligament was the strongest and largest ligament, and it was typically assembled as a group of ligaments with a fan-like arrangement. The inferior parasellar ligament was the first to be encountered after opening the anterior wall of the CS during an interdural transcavernous approach.CONCLUSIONSThe authors introduce a classification of the parasellar ligaments and their role in anchoring the medial wall of the CS. These ligaments should be identified and transected to safely mobilize the medial wall away from the cavernous ICA during a transcavernous approach and for safe and complete resection of adenomas that selectively invade the medial wall.

Bilateral coagulation of inferior hypophyseal artery and pituitary transposition during endoscopic endonasal interdural posterior clinoidectomy: do they affect pituitary function?

OBJECTIVEThe endoscopic endonasal transcavernous approach with interdural pituitary transposition provides surgical access to the posterior clinoids and interpeduncular cistern. Prior to posterior clinoidectomy, selective coagulation and transection of the inferior hypophyseal artery (IHA) is recommended to prevent uncontrolled tearing of the artery and its avulsion from the wall of the cavernous carotid artery. The authors preliminary experience has shown that unilateral sacrifice of the IHA caused no permanent endocrine dysfunction. In this study, they investigated the pituitary function in the setting of bilateral sacrifice of IHAs and pituitary transposition.METHODSAll patients with normal preoperative pituitary function who underwent endoscopic endonasal bilateral posterior clinoidectomy with bilateral IHA sacrifice between March 2010 and December 2016 were included and retrospectively evaluated. All data regarding pituitary function were collected. The degree of pituitary gland manipulation was estimated based on tumor size on preoperative MRI. An angle between a line from the point where the gland meets the floor of the sella to the highest point of the tumor and the horizontal plane of the sellar floor, or access angle, was also measured. Posterior pituitary bright spots on pre- and postoperative T1-weighted MRI were also reported.RESULTSTwenty patients had bilateral transcavernous posterior clinoidectomies with coagulation of both IHAs. There were 13 chordomas, 3 epidermoid cysts, 2 chondrosarcomas, 1 meningioma, and 1 hemangiopericytoma. The mean follow-up was 19 months (range 13-84 months). Two patients experienced transient diabetes insipidus (DI) requiring desmopressin, which resolved before hospital discharge. One patient (with chordoma) developed delayed permanent DI, and a second patient (with hemangiopericytoma) developed permanent DI and panhypopituitarism. The access angle was higher in the group with pituitary dysfunction (47.25° compared to 33.81°; p = 0.07). Posterior pituitary bright spots were preserved in 75% of cases with normal postoperative endocrine function.CONCLUSIONSThe endoscopic endonasal transcavernous approach to the interpeduncular cistern with pituitary transposition and bilateral sacrifice of the IHAs does not cause pituitary dysfunction in a majority of patients. When endocrine deficit occurs, it appears to be more likely to have been caused by surgical manipulation than loss of blood supply. This finding confirms clinically the crucial concept of interarterial anastomosis of pituitary vasculature proposed by anatomists.

Surgical anatomy of the superior hypophyseal artery and its relevance for endoscopic endonasal surgery

OBJECTIVEThe endoscopic endonasal approach has become a routine corridor to the suprasellar region. The superior hypophyseal arteries (SHAs) are intimately related to lesions in the suprasellar space, such as craniopharyngiomas and meningiomas. Here the authors investigate the surgical anatomy and variations of the SHA from the endoscopic endonasal perspective.METHODSThirty anatomical specimens with vascular injection were used for endoscopic endonasal dissection. The number of SHAs and their origin, course, branching, anastomoses, and areas of supply were collected and analyzed.RESULTSA total of 110 SHAs arising from 60 internal carotid arteries (ICAs), or 1.83 SHAs per ICA (range 0-3), were found. The most proximal SHA always ran in the preinfundibular space and provided the major blood supply to the infundibulum, optic chiasm, and proximal optic nerve; it was defined as the primary SHA (pSHA). The more distal SHA(s), present in 78.3% of sides, ran in the retroinfundibular space and supplied the stalk and may also supply the tuber cinereum and optic tracts. In the two sides (3.3%) in which no SHA was present, the territory was covered by a pair of infundibular arteries originating from the posterior communicating artery. Two-thirds of the pSHAs originated proximal to the distal dural ring; half of these arose from the carotid cave portion of the ICA, whereas the other half originated proximal to the cave. Four branching patterns of the pSHA were recognized, with the most common pattern (41.7%) consisting of three or more branches with a tree-like pattern. Descending branches were absent in 25% of cases. Preinfundibular anastomoses between pSHAs were found in all specimens. Anastomoses between the pSHA and the secondary SHA (sSHA) or the infundibular arteries were found in 75% cases.CONCLUSIONSThe first SHA almost always supplies the infundibulum, optic chiasm, and proximal optic nerve and represents the pSHA. Compromising this artery can cause a visual deficit. Unilateral injury to the pSHA is less likely to cause an endocrine deficit given the arterys abundant anastomoses. A detailed understanding of the surgical anatomy of the SHA and its many variations may help surgeons when approaching challenging lesions in the suprasellar region.