Pituitary Center Research

Abstract

Emerging evidence from multiple highly specialized groups continues to support a role for resection of the medial wall of the cavernous sinus when it is invaded by functional pituitary adenomas, to offer durable biochemical remission. The authors present two cases of Cushing's disease that underscore the power of this surgical technique in achieving remission in microadenomas that ectopically present in the cavernous sinus or have invaded the medial wall of the sinus. This video demonstrates key steps in the safe removal of the medial wall of the cavernous sinus and successful resection of tumor burden in the cavernous sinus for sustained postoperative remission. The video can be found here: https://stream.cadmore.media/r10.3171/2023.4.FOCVID2323.

View details for DOI 10.3171/2023.4.FOCVID2323

View details for PubMedID 37416808

Abstract

Pituitary tumors (PTs) continue to present unique challenges given their proximity to the cavernous sinus, whereby invasive behavior can limit the extent of resection and surgical outcome, especially in functional tumors. The aim of this study was to elucidate patterns of cavernoinvasive behavior by PT subtype.A total of 169 consecutive first-time surgeries for PTs were analyzed; 45% of the tumors were functional. There were 64 pituitary transcription factor-1 (PIT-1)-expressing, 62 steroidogenic factor-1 (SF-1)-expressing, 38 T-box transcription factor (TPIT)-expressing, and 5 nonstaining PTs. The gold standard for cavernous sinus invasion (CSI) was based on histopathological examination of the cavernous sinus medial wall and intraoperative exploration.Cavernous sinus disease was present in 33% of patients. Of the Knosp grade 3 and 4 tumors, 12 (19%) expressed PIT-1, 7 (11%) expressed SF-1, 8 (21%) expressed TPIT, and 2 (40%), were nonstaining (p = 0.36). PIT-1 tumors had a significantly higher predilection for CSI: 53% versus 24% and 18% for TPIT and SF-1 tumors, respectively (OR 6.08, 95% CI 2.86-13.55; p < 0.001). Microscopic CSI-defined as Knosp grade 0-2 tumors with confirmed invasion-was present in 44% of PIT-1 tumors compared with 7% and 13% of TPIT and SF-1 tumors, respectively (OR 11.72, 95% CI 4.35-35.50; p < 0.001). Using the transcavernous approach to excise cavernous sinus disease, surgical biochemical remission rates for patients with acromegaly, prolactinoma, and Cushing disease were 88%, 87%, and 100%, respectively. The granule density of PIT-1 tumors and corticotroph functional status did not influence CSI.The likelihood of CSI differed by transcription factor expression; PIT-1-expressing tumors had a higher predilection for invading the cavernous sinus, particularly microscopically, compared with the other tumor subtypes. This elucidates a unique cavernoinvasive behavior absent in cells from other lineages. Innovative surgical techniques, however, can mitigate tumor behavior and achieve robust, reproducible biochemical remission and gross-total resection rates. These findings can have considerable implications on the surgical management and study of PT biology and behavior.

View details for DOI 10.3171/2023.3.JNS221949

View details for PubMedID 37119095

Abstract

BACKGROUND: Safe exposure of the lacerum segment of the carotid artery remains a challenge in endoscopic endonasal surgery.OBJECTIVE: To introduce the pterygosphenoidal triangle as a novel and reliable landmark for facilitating access to the foramen lacerum.METHODS: Fifteen colored silicone-injected anatomic specimens were dissected using an endoscopic endonasal approach to the foramen lacerum region in a stepwise manner. Twelve dried skulls were studied and 30 high-resolution computed tomography scans were analyzed to measure the borders and angles of the pterygosphenoidal triangle. Surgical cases incorporating the foramen lacerum exposure between July 2018 and December 2021 were reviewed to provide surgical outcomes of the proposed surgical technique.RESULTS: The pterygosphenoidal triangle is delineated by the pterygosphenoidal fissure medially and the vidian nerve laterally. The palatovaginal artery is located at the base of the triangle anteriorly, while the apex is formed by the pterygoid tubercle posteriorly, which leads to the anterior wall of the foramen lacerum and lacerum internal carotid artery. In the reviewed surgical cases, 39 patients underwent 46 foramen lacerum approaches for resection of pituitary adenoma (12 patients), meningioma (6 patients), chondrosarcoma (5 patients), chordoma (5 patients), or other lesions (11 patients). There were no carotid injuries or ischemic events. Near-total resection was achieved in 33 (85%) of 39 patients (gross-total in 20 [51%]).CONCLUSION: This study details the pterygosphenoidal triangle as a novel and practical anatomic surgical landmark for safe and effective exposure of the foramen lacerum in endoscopic endonasal surgery.

View details for DOI 10.1227/ons.0000000000000627

View details for PubMedID 37071748

Abstract

Recurrence and biochemical remission rates vary widely among different histological subtypes of pituitary adenoma. In this prospective study, we evaluated 107 consecutive primary pituitary adenomas operated on by a single neurosurgeon including 28 corticotroph, 27 gonadotroph, 24 somatotroph, 17 lactotroph, 5 null-cell and 6 plurihormonal. In each case, we performed direct endoscopic intraoperative inspection of the medial wall of the cavernous sinus, which was surgically removed when invasion was visualized. This was performed irrespective of tumor functional status. Medial wall resection was performed in 47% of pituitary adenomas, and 39/50 walls confirmed pathologic evidence of invasion, rendering a positive predictive value of intraoperative evaluation of medial wall invasion of 78%. We show for the first-time dramatic disparities in the frequency of medial wall invasion among pathological subtypes. Somatotroph tumors invaded the medial wall much more often than other adenoma subtypes, 81% intraoperatively and 69% histologically, followed by plurihormonal tumors (40%) and gonadotroph cell tumors (33%), both with intraoperative positive predictive value of 100%. The least likely to invade were corticotroph adenomas, at a rate of 32% intraoperatively and 21% histologically, and null-cell adenomas at 0%. Removal of the cavernous sinus medial wall was not associated with permanent cranial nerve morbidity nor carotid artery injury, although 4 patients (all Knosp 3-4) experienced transient diplopia. Medial wall resection in acromegaly resulted in the highest potential for biochemical remission ever reported, with an average postoperative day 1 GH levels of 0.96 ug/L and surgical remission rates of 92% based on normalization of IGF-1 levels after surgery (mean = 15.56 months; range 3-30 months). Our findings suggest that tumor invasion of the medial wall of the cavernous sinus may explain the relatively low biochemical remission rates currently seen for acromegaly and illustrate the relevance of advanced intradural surgical approaches for successful and durable outcomes in endonasal pituitary surgery for functional adenomas.

View details for DOI 10.1038/s41598-022-12980-1

View details for PubMedID 35705579

Abstract

OBJECTIVE: The clinoidal venous space dorsal to the internal carotid artery (ICA) has not been well studied given its inaccessibility due to obstruction by the ICA during transcranial surgery. The evolution of endoscopic endonasal surgery has provided a new perspective into the clinoidal space and a new route for paraclinoidal lesions. Understanding the dorsal clinoidal space (DCS) is vital in planning and performing endoscopic endonasal surgery in the parasellar region. A detailed and precise description of the DCS from the endonasal perspective has not yet been provided. The authors' goal in this study was to delineate the microsurgical anatomy of the DCS from an endoscopic endonasal perspective, emphasizing its surgical implications when treating invasive pituitary adenomas and other parasellar lesions.METHODS: An endoscopic endonasal transsellar approach was performed in 15 silicone-injected postmortem heads. Afterward, the sellar region was dissected through a transcranial approach using magnification *3 to *40 microscopy. The osseous, dural, and arterial relationships of the DCS and its architecture were investigated. The DCS's length, width, and depth were measured and its anatomical variations recorded.RESULTS: The DCS was identified in 90% of the specimens, and in most cases, its shape was a narrow rectangular pyramid, with its base oriented toward the sphenoid sinus and its apex toward the posterior clinoid process. It is delimited superiorly by the distal ring, inferiorly by the medial aspect of the proximal dural ring or caroticoclinoid ligament, laterally by the clinoidal ICA, and medially by the superior continuation of the medial wall of the cavernous sinus. The width, height, and length of the DCS were 4 ± 1, 4.5 ± 1.5, and 7 ± 2 mm, respectively. A fenestrated caroticoclinoid ligament is a potential route for tumor invasion from the cavernous sinus into the DCS.CONCLUSIONS: This report provides important anatomical descriptions of the DCS from endoscopic endonasal and transcranial perspectives that may facilitate the space's safe exposure for the removal of invasive adenomas, increasing total resection rates and minimizing the risk of injury to neurovascular structures.

View details for DOI 10.3171/2021.12.JNS211974

View details for PubMedID 35120312

View details for DOI 10.3171/2021.12.JNS212024.

View details for Web of Science ID 000891788200002

Abstract

BACKGROUND: The endoscopic endonasal approach is a surgical alternative for midline anterior skull base tumors. A detailed understanding of the proximal anterior cerebral artery (ACA) branches' anatomy from an endonasal perspective is essential for avoiding vascular complications.OBJECTIVE: To evaluate, from an endonasal perspective, the anatomic variations of the ACA and its proximal branches, specifically the recurrent artery of Heubner (RAH), and the fronto-orbital (FOA) and frontopolar (FPA) arteries.METHODS: We study the origin, course, branching pattern, diameter, and relationship between the proximal ACA branches and the optic apparatus and olfactory tract in 25 head specimens.RESULTS: The RAH was present in all hemispheres and originated within 3±1.5 mm of the AcomA, with a 0.4±0.1 mm diameter. Based on its relationship with the A1 segment, we observed three RAH courses: anterior (40%), superior (22%), and posterior (38%). The FOA was present in all cases, a mean of 6±4 mm from the AcomA, with a 0.7±0.4 mm diameter. The FOA arose mainly from the A2 (70%), with three courses in relation to the olfactory tract: crossing its proximal third (54%), crossing its middle third (31%), and running parallel to it along the gyrus rectus (15%). The FPA was present in 92% of the hemispheres, a mean of 10±5 mm from the AcomA, always arising from the A2 and coursing anteriorly within the interhemispheric fissure towards the frontal pole.CONCLUSION: The RAH, FOA, and FPA can be differentiated by origin, course, and destination using the A1 segment, olfactory tract, and interhemispheric fissure, respectively, as surgical landmarks.

View details for PubMedID 30649510

Abstract

BACKGROUND: A simple, reliable grading scale to better characterize nonfunctioning pituitary adenomas (NFPAs) preoperatively has potential for research and clinical applications.OBJECTIVE: To develop a grading scale from a prospective multicenter cohort of patients that accurately and reliably predicts the likelihood of gross total resection (GTR) after transsphenoidal NFPA surgery.METHODS: Extent-of-resection (EOR) data from a prospective multicenter study in transsphenoidal NFPA surgery were analyzed (TRANSSPHER study; ClinicalTrials.gov NCT02357498). Sixteen preoperative radiographic magnetic resonance imaging (MRI) tumor characteristics (eg, tumor size, invasion measures, tumor signal characteristics, and parameters impacting surgical access) were evaluated to determine EOR predictors, to calculate receiver-operating characteristic curves, and to develop a grading scale. A separate validation cohort (n=165) was examined to assess the scale's performance and inter-rater reliability.RESULTS: Data for 222 patients from 7 centers treated by 15 surgeons were analyzed. Approximately one-fifth of patients (18.5%; 41 of 222) underwent subtotal resection (STR). Maximum tumor diameter>40 mm; nodular tumor extension through the diaphragma into the frontal lobe, temporal lobe, posterior fossa, or ventricle; and Knosp grades 3 to 4 were identified as independent STR predictors. A grading scale (TRANSSPHER grade) based on a combination of these 3 features outperformed individual variables in predicting GTR (AUC, 0.732). In a validation cohort, the scale exhibited high sensitivity and specificity (AUC, 0.779) and strong inter-rater reliability (kappa coefficient, 0.617).CONCLUSION: This simple, reliable grading scale based on preoperative MRI characteristics can be used to better characterize NFPAs for clinical and research purposes and to predict the likelihood of achieving GTR.

View details for PubMedID 30649445

Abstract

The surgical goal for low-grade gliomas (LGGs) is to maximize resection while minimizing morbidity. Pan-hippocampal LGGs extend from the hippocampal head to the hippocampal tail, and involve the parahippocampal gyrus and uncus. Given their anteroposterior extension, they cannot be completely removed with 1 single approach, requiring a 2-stage front-to-back operation.In this video, we present the case of a 52-yr-old man with new onset of generalized seizures and a dominant-side, nonenhancing, pan-hippocampal infiltrative lesion compatible with a low-grade glioma. Preoperative high-definition fiber tractography (HDFT) showed the spatial relationship of the tumor with surrounding fiber tracts, such as the arcuate, inferior fronto-occipital, and middle longitudinal fascicles, and optic radiations.Surgical resection was planned in 2 separate stages. The first stage consisted of a transsylvian transinferior insular sulcus approach to the extra- and intraventricular aspects of the uncohippocampal region. The entire anterior and middle portions of the tumor were successfully removed with minimal morbidity, including transient naming difficulties and permanent superior quadrantanopia. Postoperative HDFT showed preservation of all fiber tracts, except for a portion of Meyer's loop and the inferior-most aspect of the inferior fronto-occipital fascicle. The second stage was completed 8 wk later and consisted of a paramedian supracerebellar-transtentorial approach on sitting position. The posterior portion of the tumor was entirely removed to achieve a complete macroscopic tumor resection. The final diagnosis was IDH1-positive LGG.Pan-hippocampal tumors remain a surgical challenge but accurate knowledge of surgical neuroanatomy and surgical approaches facilitates their safe and effective treatment.The patient signed an informed consent including the use of photographic and video material for educational or academic purposes.

View details for PubMedID 30295907

Abstract

In this video, we present the case of a 41-yr-old female with new onset of recurrent syncopal episodes. She underwent extensive evaluations and diagnostic work-up by cardiology and neurology, excluding any other cause than a large pineal cyst that was found on magnetic resonance imaging.Surgical indications for pineal cyst resection are very limited as most pineal cyst can be treated conservatively. Recurrent drop-attacks (without loss of consciousness) or syncopal episodes (with brief loss of consciousness) have been associated with pineal cysts secondary to a possible ball valve effect with shift of position causing sudden obstruction of the ventricular system followed by rapid rising of intracranial pressure.Several approaches, different positions, and alternative surgical techniques (microscopic vs endoscopic) have been proposed for resection of pineal region lesions. The semi-sitting position provides excellent exposure of the pineal region secondary to gravity-based retraction of the cerebellum, and carries minimal risk of air venous embolism when head elevation is reduced to 30° and lower extremities are elevated. The paramedian supracerebellar approach is less invasive and faster than midline supracerebellar approach, because it requires exposure of just 1 transverse sinus (nondominant for centered lesions) and avoids exposure of the torcula. The endoscopic technique greatly improves the ergonomics of the approach when compared to the microscope based technique, and provides excellent visualization of all the neurovascular structures in the pineal region.Surgical resection was successfully performed with no complications and complete cyst resection. Patient was discharged on postoperative day 1 and remains free of syncopal episodes.The patient signed informed consent including the use of photographic and video material for educational or academic purposes.

View details for PubMedID 30295900