Pituitary Stalk Stretch Predicts Postoperative Diabetes Insipidus After Pituitary Macroadenoma Transsphenoidal Resection.

BACKGROUND: Manipulation of the pituitary stalk, posterior pituitary gland, and hypothalamus during transsphenoidal pituitary adenoma resection can cause disruption of water electrolyte regulation leading to diabetes insipidus (DI). OBJECTIVE: To determine whether pituitary stalk stretch is an independent risk factor for postoperative DI after pituitary adenoma resection. METHODS: A retrospective review was performed of patients undergoing endoscopic endonasal resection of pituitary macroadenoma between July 2010 and December 2016 by a single neurosurgeon. We analyzed preoperative and postoperative imaging metrics to assess predictors for postoperative DI. RESULTS: Of the 234 patients undergoing resection, 41 (17.5%) developed postoperative DI. DI was permanent in 10 (4.3%) and transient in 31 (13.2%). The pituitary stalk stretch, measured as the change in stalk length from preoperative to postoperative imaging, was greater in the DI compared with the non-DI group (10.1 mm vs 5.9 mm, P < .0001). The pituitary stalk stretch was associated with DI with significant difference in mean pituitary stalk stretch between non-DI group vs DI group (5.9 mm vs 10.1 mm, P < .0001). Multivariate analysis revealed that pituitary stalk stretch >10 mm was a significant independent predictor of postoperative DI [odds ratios = 2.56 (1.10-5.96), P = .029]. When stratified into transient and permanent DI, multivariable analysis showed that pituitary stalk stretch >10 mm was a significant independent predictor of transient DI [odds ratios = 2.71 (1.0-7.1), P = .046] but not permanent DI. CONCLUSION: Postoperative pituitary stalk stretch after transsphenoidal pituitary adenoma surgery is an important factor for postoperative DI. We propose a reconstruction strategy to mitigate stalk stretch.

A Surgical Perspective on the Association between Cystic Lesions of the Pineal Gland (Descartes' Seat of the Soul) and the Pituitary (the Master Gland).

Introduction Rene Descartes (1596-1650), the famous philosopher and scientist, identified the pineal gland as the only cerebral structure not represented bilaterally, the "seat of the soul"; and the source of rational thought. Pineal cysts (PCs) are often incidentally identified in MRI studies, with a reported prevalence of 1 to 4.3%. Rathke cleft cysts (RCCs) are pituitary lesions accounting for <1% of intracranial masses. There are scant data in the literature addressing any association between these two midline cystic lesions. Methods We reviewed the medical records of patients presenting at our institution from April 2008 through February 2020, whose records indicated a diagnosis of RCC, and those whose records included pineal lesions. Our objective was to evaluate the association between these two midline lesions. Brain MRI studies were reviewed for the presence of PCs; only patients with PCs that measured ≥5 mm in diameter were included. Results We identified 116 patients with RCCs, and 34 patients with PCs, treated from April 2008 through February 2020. Among the RCC group, 14/116 patients (12%) had PCs. Among the PC group, 3/34 patients (8.8%) had RCCs. Overall, 17 patients (11.3%) had concomitant RCCs and PCs. The mean maximal diameter of the PCs was 7.5 mm (range = 5-17 mm), whereas the mean maximal diameter of RCCs was 13 mm (range = 5-40 mm). Conclusion The incidental diagnosis of cystic lesions of the pineal and pituitary gland is increasingly reported, primarily because of advances in current diagnostic modalities. Our data demonstrated no clear consensual association between pineal and pituitary cysts.

Ivy sign: a diagnostic and prognostic biomarker for pediatric moyamoya.

OBJECTIVE: Ivy sign is a radiographic finding on FLAIR MRI sequences and is associated with slow cortical blood flow in moyamoya. Limited data exist on the utility of the ivy sign as a diagnostic and prognostic tool in pediatric patients, particularly outside of Asian populations. The authors aimed to investigate a modified grading scale with which to characterize the prevalence and extent of the ivy sign in children with moyamoya and evaluate its efficacy as a biomarker in predicting postoperative outcomes, including stroke risk. METHODS: Pre- and postoperative clinical and radiographic data of all pediatric patients (21 years of age or younger) who underwent surgery for moyamoya disease or moyamoya syndrome at two major tertiary referral centers in the US and Israel, between July 2009 and August 2019, were retrospectively reviewed. Ivy sign scores were correlated to Suzuki stage, Matsushima grade, and postoperative stroke rate to quantify the diagnostic and prognostic utility of ivy sign. RESULTS: A total of 171 hemispheres in 107 patients were included. The median age at the time of surgery was 9 years (range 3 months-21 years). The ivy sign was most frequently encountered in association with Suzuki stage III or IV disease in all vascular territories, including the anterior cerebral artery (53.7%), middle cerebral artery (56.3%), and posterior cerebral artery (47.5%) territories. Following surgical revascularization, 85% of hemispheres with Matsushima grade A demonstrated a concomitant, statistically significant reduction in ivy sign scores (OR 5.3, 95% CI 1.4-20.0; p = 0.013). Postoperatively, revascularized hemispheres that exhibited ivy sign score decreases had significantly lower rates of postoperative stroke (3.4%) compared with hemispheres that demonstrated no reversal of the ivy sign (16.1%) (OR 5.5, 95% CI 1.5-21.0; p = 0.008). CONCLUSIONS: This is the largest study to date that focuses on the role of the ivy sign in pediatric moyamoya. These data demonstrate that the ivy sign was present in approximately half the pediatric patients with moyamoya with Suzuki stage III or IV disease, when blood flow was most unstable. The authors found that reversal of the ivy sign provided both radiographic and clinical utility as a prognostic biomarker postoperatively, given the statistically significant association with both better Matsushima grades and a fivefold reduction in postoperative stroke rates. These findings can help inform clinical decision-making, and they have particular value in the pediatric population, as the ability to minimize additional radiographic evaluations and tailor radiographic surveillance is requisite.

Professor Rathke's gift to neurosurgery: the cyst, its diagnosis, surgical management, and outcomes.

PURPOSE: Rathke cleft cysts (RCC) are a target for transsphenoidal surgery when symptomatic; however, the surgical techniques and outcomes continue to be of interest. Our goal is to highlight nuances in diagnosis, surgical philosophy and techniques, and outcomes. METHODS: We retrospectively reviewed a single surgeon experience in a contemporary series of RCC from April 2008 through December 2019. The clinical presentation, radiographic studies, intraoperative findings, histopathological diagnosis, postoperative complications, and outcome data were recorded and analyzed. RESULTS: A total of 131 endoscopic endonasal operations were performed on 116 patients (30 male, 86 female), with an average age of 39 years. We identified 102 patients without prior surgery, and 14 patients with prior surgery elsewhere. Postoperative complications included transient diabetes insipidus (DI) (n = 23, 20%), permanent DI (n = 5, 4%), SIADH (n = 6, 5%), epistaxis (n = 6, 5%), postoperative infection (n = 3, 2.5%), postoperative CSF leak (n = 1, < 1%), intrasellar hematoma (n = 1, < 1%), and stroke (n = 1, < 1%). Visual improvement was observed in 74% (n = 31/42) of patients presenting with visual loss, and headache improvement in 86% (n = 80/93). Overall, the recurrence rate in our cohort was 11%, with a lower recurrence rate seen in males (p = 0.02). The median follow-up duration was 15.2 months (interquartile range 1.7-52.3) CONCLUSION: Our results reflect the philosophy of a conservative surgical approach, designed to preserve normal pituitary function, and avoid DI, while achieving the maximal feasible resection. Evacuation of the cyst contents and meticulous sampling of the cyst wall when possible for histopathological diagnosis are crucial. The postoperative relief of symptoms and signs is gratifying, as are the overall rates of recurrence and outcomes.

Collagen Matrix With Mucoperiosteum Graft as an Effective Fatless Flapless Reconstruction After Endoscopic Pituitary Adenoma Resection.

BACKGROUND: Proper skull base reconstruction after endoscopic endonasal pituitary surgery is of great importance to decrease the rate of complications. OBJECTIVE: To assess the safety and efficacy of reconstruction with materials other than fat graft and naso-septal flaps (NSF) to avoid their associated morbidities. METHODS: The authors' institutional database for patients who underwent endoscopic endonasal approach for pituitary adenoma was reviewed. Exclusion criteria included recurrence, postradiation therapy, and reconstruction by fat graft or NSF. They were divided into group A, where collagen matrix (CM) (DuraGen® Plus Matrix, Integra LifeSciences Corporation, Plainsboro, New Jersey) alone was used; group B, where CM and simple mucoperiosteum graft were used and group C, which included cases without CM utilization. RESULTS: The study included 252 patients. No age, gender, or body mass index statistically significant difference between groups. Group B included the largest tumor size (23.0 mm) in comparison to groups A (18.0 mm) and C (13.0 mm). Suprasellar extension was more frequently present (49.4%) in comparison to groups A (29.8%, P = .001) and C (21.2%, P < .001). Postoperative cerebrospinal fluid (CSF) leak rate was 0%, 2.9%, and 6% in groups A, B, and C, respectively. In group B, the CSF leak rate decreased from 45.9% intraoperatively to 2.9% postoperatively (P < .001). In group A, the CSF leak reduction rate was almost statistically significant (P = .06). CONCLUSION: Utilization of CM and simple mucosperiosteal graft in skull base reconstruction following pituitary adenoma surgery is an effective method to avoid the morbidities associated with NSF or fat graft.

Minimally Invasive Approaches to the Lateral Cavernous Sinus and Meckel's Cave: Comparison of Transorbital and Subtemporal Endoscopic Techniques.

BACKGROUND: Transorbital and subtemporal keyhole approaches have recently been proposed to approach lesions in the lateral wall of the cavernous sinus (CS) and Meckel's cave (MC). Our goal was to compare these approaches and suggest indications for each of them. METHODS: Five cadaver heads (10 sides, 40 procedures) were used. The lateral transorbital approaches were carried out without and with the removal of the lateral orbital rim, herein referred to as the lateral transorbital approach (LTOA) and the lateral orbital wall approach (LOWA). The subtemporal approaches were performed without and with the removal of the zygomatic arch, referred to as the subtemporal approach (STA) and the subtemporozygomatic approach (STZA). Five targets were chosen and 2 triangles were created representing the lateral wall of the CS and MC. Stereotactic measurements were quantified to calculate angles of attack, surgical freedom, and temporal lobe retraction for each approach. RESULTS: LTOA presented the smaller horizontal angles of attack. LOWA increased the angles to the same level of STA and STZA. STA and STZA presented larger vertical angles of attack. The surgical freedom presented gradual increase from LTOA to LOWA, STA, and STZA. STA and STZA needed greater temporal lobe retraction for most targets. CONCLUSIONS: LTOA is a good option to biopsy a lesion in the lateral wall of the CS and LOWA increased the surgical corridor to work with microsurgical techniques. STA and STZA could be better options when wide exposure is necessary, but temporal lobe retraction should be taken into consideration.

Extended Endoscopic Endonasal Clipping of Intracranial Aneurysms: An Anatomic Feasibility Study.

BACKGROUND: Intracranial aneurysms (IAs) located in the midline region represent formidable challenge owing to their deep location. The objective of this study was to assess feasibility and identify the limitations of endoscopic endonasal clipping of IAs. We further aimed to describe the locations and characteristics of aneurysms that may be amenable for endoscopic endonasal clipping; thus outlining the indications of these approaches. METHODS: Fifteen latex-injected cadaveric heads were used for endoscopic endonasal exposure of anterior and posterior cerebral circulations. An aneurysm simulator model with 2 different sizes was used at the common sites for IAs to emulate a real surgery. Key measured parameters included "exposure of vessels and their respective perforators," "ability to gain proximal/distal control," and "possibility of clip placement" according to the size, direction, and location of the aneurysm model. Maneuverability of instruments and the need for pituitary gland transposition were assessed and recorded as well. RESULTS: Exposure of the anterior communicating artery complex and the common sites of posterior circulation aneurysms were feasible. The size, location, and direction of the aneurysm model had an impact on obtaining proximal and/or distal control, and the ability of clip placement. CONCLUSIONS: Clipping of midline aneurysms of the posterior circulation is feasible via endoscopic endonasal approach. Small-sized ventrally and medially directed aneurysm models carried a better probability of getting proximal and/or distal control, as well as better overall ability to place a clip. The endonasal route seems to provide a limited condition for proper management of anterior circulation aneurysms.

Pituitary carcinomas: review of the current literature and report of atypical case.

Introduction: Pituitary carcinomas are poorly understood, rare entities. They are distinguished from adenomas not by histopathological features but rather by the presence of metastases.Objective: We discuss the diagnosis, mechanism of dissemination and pathogenesis based on a review of the literature and illustrated by a singular case.Case Report: A 59-year-old male presented with a dural-based posterior fossa lesion. He had been diagnosed with a pituitary chromophobe adenoma 43 years earlier that was treated at the time with surgery and radiation therapy. A presumptive diagnosis of a radiation-induced meningioma was made and surgery was recommended. At surgery the tumour resembled a pituitary adenoma. Histopathology, laboratory findings, and the patient's medical history confirmed the final diagnosis of a prolactin-secreting pituitary carcinoma. To our knowledge, this is the longest reported interval between the pituitary adenoma and metastatic lesion diagnosis (43 years).Conclusion: Management should be tailored to individual patient and may include a combination of treatments (surgery, radiation therapy, chemotherapy, and hormone-targeted therapy). Functionally active tumours may be monitored with hormone levels as tumour markers.

Giant Olfactory Groove Meningioma-2-Staged Approach: 2-Dimensional Operative Video.

A 42-yr-old female presented with an olfactory groove meningioma causing progressive vision loss and anosmia. Given the size of the tumor, we opted for a 2-stage surgery: endoscopic endonasal approach (EEA) followed by a craniotomy. Stage I surgery was a transcribriform transplanum EEA using a binostril 4-hand/2 surgeons (ENT and neuro) technique, with the patient positioned supine with the head slightly turned to the right side and tilted to the left, fixed in a 3-pin head clamp, under imaging guidance, in which we drilled out all the affected skull base bone, devascularized and debulked the tumor. Stage II surgery was done through a right frontotemporal craniotomy 2 mo later. The surgery and postoperative period was uneventful with no complications and no need for further reconstruction of the skull base. The patient's vision was normalized. Postoperative magnetic resonance imaging (MRI) confirmed a Simpson Grade 1 resection. The rationale behind this staged approach is that we have found when using a transcranial 1-stage approach the brain edema and necessary retraction required for resection leads to brain injury, oftentimes readily identified in the diffusion-weighted imaging MRI which are associated with different degrees of cognitive impairment. The skull base bone involved is usually not removed via transcranial approaches. Despite requiring a second surgery, this staged approach allows a true total resection (including the affected bone) and in the transcranial stage the brain is more relaxed, with less edema, reducing the need for retraction, which may lead to a better outcome. The patient has given assent and written consent for videos, images, or clinical or genetic information to be published.

Endoscopic Endonasal Focal Transclival-Medial Condylectomy Approach for Resection of a Foramen Magnum Meningioma: 2-Dimensional Operative Video.

The endoscopic endonasal approach (EEA) provides direct access to foramen magnum meningiomas; however, it often requires extensive exposure including septal flap elevation with septum removal, complete sphenoidotomy, and panclivectomy.We present a case of a 54-yr-old-female with an incidental foramen magnum lesion followed up with serial imaging who presented 10 mo later with progressive neck discomfort and episodes of dizziness, with confirmed tumor progression and further brainstem compression. A focal transclival EEA with medial condylectomy was performed preserving the upper two-thirds of the clivus, the nasal septum, and the sphenoid sinus. Gross total removal of a meningioma WHO Grade-1 was achieved with dura resection on the majority of the tumor (Simpson 2). Closure was achieved with a random pedicled inverted V nasaopharyngeal flap. There were no complications, all symptoms improved, and no recurrence was seen in 12 mo of follow-up.IRB approval was neither required nor saught for this single case report. The patient gave informed consent.

Role of Endoscopy in Resection of Intracanalicular Vestibular Schwannoma via Middle Fossa Approach: Technical Nuances.

BACKGROUND: Surgical resection of vestibular schwannomas (VS) located within the internal auditory canal (IAC) is challenging, especially those located very laterally in the IAC. Various transcranial approaches have been described for resection of intracanalicular VS including retrosigmoid, translabyrinthine, and middle fossa approaches. Each approach has its indications, advantages, and limitations. The middle fossa approach (MFA) is considered by many authors as the gold standard approach for resection of small intracanalicular VS in young patients with serviceable hearing; however, there is often a limitation in complete visualization of the tumor. METHODS: The authors present an illustrative case to highlight the technical nuances of complementary use of endoscopy in MFA for complete resection of intracanalicular VS located at the IAC fundus, preserving preoperative hearing status and mainting intact facial nerve function. RESULTS: In our experience, the combined use of the endoscope and the microspe as described here and illustrated in our case, improves visualization of the IAC and its contents, improving ressection and outcomes. CONCLUSIONS: MFA allows for a direct yet safe surgical corridor to small intracanalicular VS. The implementation of endoscopy with MFA, especially for VS located laterally in the IAC, allows for better opportunity for complete resection of the tumor with improved preservation of hearing and facial nerve function.

Predictors of Postoperative Diabetes Insipidus Following Endoscopic Resection of Pituitary Adenomas.

CONTEXT: The development of diabetes insipidus (DI) following transsphenoidal resection of pituitary adenomas has been associated with higher postsurgical morbidity and longer hospitalizations. Identifying these patients promptly and efficiently can lead to improved health care outcomes. OBJECTIVE: We evaluated our institution's incidence of DI following pituitary adenoma resection and assessed for preoperative risk factors that were associated with postoperative DI. DESIGN: A retrospective review of 271 patients who underwent endoscopic endonasal resection of a pituitary adenoma between July 2010 and December 2016 by a single neurosurgical provider was completed. SETTING: All cases were from a single-center, academic institution. PATIENTS: Patients with a pituitary adenoma diagnosis confirmed on histology were included in the study. Those with previous surgery by a different provider were excluded. RESULTS: The incidence of DI at our institution was 16.6% (45 of 271 patients), with only 4% (11 patients) having permanent DI. The presence of visual abnormalities (CI 1.29 to 4.75), suprasellar extension (CI 1.36 to 6.88), and maximal tumor diameter (1.02 to 1.08) was significantly associated with an increased incidence of postoperative DI (P < 0.05). Hyperprolactinemia, tumor functionality, and cerebrospinal fluid exposure were not associated with higher rates of postoperative DI (P > 0.05). CONCLUSION: Pituitary adenoma patients presenting with visual abnormalities, suprasellar extension, or large tumors are at higher risk of developing DI postoperatively. These patients warrant closer postoperative monitoring as well as adequate preoperative counseling to decrease their postsurgical morbidity.

Endoscopic Endonasal Approach to a Suprasellar Craniopharyngioma.

We present the case of a 57-year-old male who presented with progressive right side vision loss whose workup revealed a large suprasellar lesion with invasion of the third ventricle. The pituitary stalk was not visible. Hormonal panel showed no hormonal deficits. The initial diagnosis was of a type II transinfundibular craniopharyngioma (as classified by Kassam et al). An endoscopic endonasal transplanum transtuberculum approach was done using a standard binostril four-hand technique, with the patient positioned supine with the head turned to the right side and tilted to the left, fixed in a three-pin head clamp, under imaging guidance. The tumor was carefully dissected away from the optic apparatus while preserving the vessels, mainly the superior hypophyseal artery. The stalk was identified around the tumor and preserved. The third ventricle was entered and inspected at the end of the procedure and a near-total resection (a small residual in the right hypothalamus) with decompression of the optic apparatus was achieved. Reconstruction was done in a multilayered fashion, using collagen matrix and a nasoseptal flap. Patient had an uneventful postoperative stay and was discharged on POD 4, neurologically stable with no hormonal deficits. Pathology confirmed an adamantinomatous craniopharyngioma. Due to a small growth of the residual, patient underwent fractionated stereotactic radiation (50.4Gy in 28 sessions). He presented with panhypopituitarism 2 years after radiation therapy. At 3-month follow-up, his vision was back to normal and 6-year postoperative magnetic resonance imaging showed no signs of recurrence. The link to the video can be found at: https://youtu.be/chG7XIz7a_A .

Endoscopic Endonasal Resection of Tuberculum Sellae Meningioma with Utilization of Indocyanine Green.

We present the case of a 67-year-old female with an incidental finding of a left-sided tuberculum sellae meningioma on a brain magnetic resonance imaging (MRI) for an unrelated complaint. Formal visual field testing showed a small defect in the inferior nasal and temporal fields of the left eye, compatible with mass effect on the optic nerve by the tumor. An endoscopic endonasal transtuberculum approach with decompression of the left optic nerve was performed using a standard binostril four-hand technique, with the patient positioned supine with the head turned to the right side and tilted to the left, fixed in a three-pin head clamp, under imaging guidance. After exposure, we drilled the tuberculum sellae and the floor of the sella and after opening the dura, the tumor and optic nerve came into view. The tumor was completely removed and we confirmed the patency of all perforating vessels using indocyanine green. Reconstruction was done in a multilayered fashion, using collagen matrix and a nasoseptal flap. Patient had an uneventful postoperative stay and was discharged on postoperative day 3, neurologically stable with no new hormonal deficits. Pathology report confirmed a WHO Grade I meningioma with Ki -67 of 1% and 3-month postoperative MRI confirmed a gross total resection and visual fields exam showed a complete recovery. The link to the video can be found at: https://youtu.be/zRmt2aIvX5c .

Endoscopic Endonasal Transplanum-Transtuberculum Sellae Approach for the Resection of a Diaphragma Sellae Meningioma.

The endoscopic endonasal approach (EEA) provides a direct access to diaphragma sellae meningiomas. We present a case of a 56-year-old-female with an incidentally diagnosed sellar/suprasellar lesion with no hormonal deficit; thus, she opted for conservative management initially. During her annual follow-up appointment with her ophthalmologist, it was noticed that the patient had right eye peripheral deficit on formal visual field testing. Magnetic resonance imaging (MRI) revealed an enlargement of the sellar/suprasellar mass, causing displacement of the optic chiasm. A transplanum-transtuberculum EEA was performed. Gross-total removal was achieved and closure was done in a multilayer fashion using a collagen matrix, nasoseptal flap. Histopathological examination confirmed a meningioma WHO grade I. There were no intra- or postoperative complications. At 4-year-follow-up, the patient has stable vision and MRI brain showed no recurrence. The link to the video can be found at: https://youtu.be/xY8T9hotlDs .

Endoscopic Endonasal Transtuberculum Sellae Approach for the Resection of Suprasellar Intrainfundibular Epidermoid Cyst.

A 49-year-old female presented with intense headaches of 3 months duration. Brain magnetic resonance imaging (MRI) was performed and showed a sellar-suprasellar lesion extending into the third ventricle. A presumptive diagnosis of a craniopharyngioma was made. Since the patient did not have any visual deficits, she opted for conservative management. Four months later, she started to have progressive deterioration of vision; thus, surgery was indicated. The patient underwent endoscopic endonasal resection of the lesion through a transtuberculum sellae approach. The patient was positioned supine with the head slightly extended and the face turned to the right side. Following the essence of a binostril four-hand technique, a total gross resection of the lesion was achieved and multilayer skull base reconstruction was performed utilizing collagen matrix and nasoseptal flap; with no intraoperative complications. The patient's postoperative course was uneventful with the improvement in her vision, and she was discharged on postoperative day 4 with no new neurological deficits. Histopathological examination confirmed the diagnosis of an epidermoid cyst. Postoperative pituitary gland function was within normal limits except for mild diabetes insipidus for which she is on DDAVP 0.1 mg twice daily. At 4 years follow-up, the patient was doing well, her vision was normalized, and brain MRI revealed no evidence of residual or recurrent lesion. The link to the video can be found at: https://youtu.be/OqDFpa_Xq78 .

Endoscopic Endonasal Resection of a Suprasellar Pituitary Adenoma Mimicking Tuberculum Sellae Meningioma in a Patient with an Intrasellar Persistent Trigeminal Artery.

A 50-year-old female with an incidentally diagnosed suprasellar lesion was initially managed conservatively due to the presence of an intrasellar persistent trigeminal artery going through the dorsum sellae and fundamentally forming the blood supply of the entire posterior circulation. Serial follow-up brain magnetic resonance imaging (MRI) revealed progressive enlargement of the suprasellar lesion over 4 years period. Surgery was indicated after the initial tumor growth; however, the patient refused surgery for fear of complications related to the persistent trigeminal artery. Two-and-a-half years later, she presented with deterioration of vision. Formal visual field testing revealed a right temporal field defect. Brain MRI demonstrated significantly enlarged suprasellar lesion, most consistent with tuberculum sellae meningioma, exerting mass effect on the optic apparatus. The patient underwent endoscopic endonasal resection of the lesion through a transplanum/transtuberculum approach. Intraoperatively, absence of hypertrophic McConnel arteries, hyperostosis, and the fact that the dura was soft and not under tension was against the diagnosis of tuberculum sellae meningioma. Additionally, the tumor consistency was similar to a pituitary adenoma. A complete resection was accomplished and multilayer skull base reconstruction was performed with no complications. On postoperative day 1 (POD 1), she was operated upon for the evacuation of small suprasellar hematoma associated with vision deterioration. Histopathological examination confirmed the diagnosis of atypical pituitary adenoma with Ki -67 labeling index of 4 to 5%. The patient ultimately recovered well with improved vision, and was discharged on POD 4 with no new neurological deficits. At 4 years follow-up, her vision was normalized and brain MRI showed no residual or recurrent lesion. The link to the video can be found at: https://youtu.be/QZmzctjAEbw .

The limits of the endoscopic endonasal transclival approach for posterior fossa tumors.

Endoscopic endonasal approaches (EEA) have gained popularity and acceptance in skull base surgery over the last two decades. So-called expanded EEA allow access in the sagittal plane from the frontal sinus to the odontoid process. The endoscopic endonasal transclival approach allows a unique trajectory into the midline clivus and skull base that is unachievable from traditional craniotomy approaches to lesions such as chondrosarcomas, chordomas, and posterior fossa meningiomas. In this review, we will assess the benefits and drawbacks to using an endoscopic endonasal approach versus transcranial approach to these challenging lesions, assess the anatomical limits of endoscopic endonasal transclival surgery, and discuss the published literature on the topic.

Limits of endoscopic endonasal transpterygoid approach to cavernous sinus and Meckel's cave.

The endoscopic endonasal approach (EEA) to the ventral skull base has greatly increased in popularity over the last two decades. So-called expanded EEA have opened corridors to pathology off-midline, including lesions within the cavernous sinus and Meckel's cave. A standard EEA exposure into the sphenoid sinus allows visualization of the medial cavernous sinus; a transpterygoid approach allows for surgical manipulation of the lateral cavernous sinus and Meckel's cave contents. Pituitary adenomas, meningiomas, and schwannomas are the most common pathologies in this region. This approach to the "front door" of the cavernous sinus and Meckel's cave should be considered complementary to traditional craniotomy techniques as each have benefits and limitations. Herein we review the published literature regarding endoscopic endonasal transpterygoid surgery for pathology in the lateral cavernous sinus and Meckel's cave, and the anatomical and functional limitations of these approaches.