Improved optic nerve visualization and treatment planning through a dedicated optic nerve MRI protocol.

OBJECTIVE: This study describes an innovative optic nerve MRI protocol for better delineating optic nerve anatomy from neighboring pathology. METHODS: Twenty-two patients undergoing MRI examination of the optic nerve with the dedicated protocol were identified and included for analysis of imaging, surgical strategy, and outcomes. T2-weighted and fat-suppressed T1-weighted gadolinium-enhanced images were acquired perpendicular and parallel to the long axis of the optic nerve to achieve en face and in-line views along the course of the nerve. RESULTS: Dedicated optic nerve MRI sequences provided enhanced visualization of the nerve, CSF within the nerve sheath, and local pathology. Optic nerve sequences leveraged the "CSF ring" within the optic nerve sheath to create contrast between pathology and normal tissue, highlighting areas of compression. Tumor was readily tracked along the longitudinal axis of the nerve by images obtained parallel to the nerve. The findings augmented treatment planning. CONCLUSIONS: The authors present a dedicated optic nerve MRI protocol that is simple to use and affords improved cross-sectional and longitudinal visualization of the nerve, surrounding CSF, and pathology. This improved visualization enhances radiological evaluation and treatment planning for optic nerve lesions.

Endoscopic precaruncular medial transorbital and endonasal multiport approaches to the contralateral skull base: a clinicoanatomical study.

OBJECTIVE: Minimally invasive endoscopic endonasal multiport approaches create additional visualization angles to treat skull base pathologies. The sublabial contralateral transmaxillary (CTM) approach and superior eyelid lateral transorbital approach, frequently used nowadays, have been referred to as the "third port" when used alongside the endoscopic endonasal approach (EEA). The endoscopic precaruncular contralateral medial transorbital (cMTO) corridor, on the other hand, is an underrecognized but unique port that has been used to repair CSF rhinorrhea originating from the lateral sphenoid sinus recess. However, no anatomical feasibility studies or clinical experience exists to assess its benefits and demonstrate its potential role in multiport endoscopic access to the other contralateral skull base areas. In this study, the authors explored the application and potential utility of multiport EEA combined with the endoscopic cMTO approach (EEA/cMTO) to three target areas of the contralateral skull base: lateral recess of sphenoid sinus (LRSS), petrous apex (PA) and petroclival region, and retrocarotid clinoidocavernous space (CCS). METHODS: Ten cadaveric specimens (20 sides) were dissected bilaterally under stereotactic navigation guidance to access contralateral LRSS via EEA/cMTO. The PA and petroclival region and retrocarotid CCS were exposed via EEA alone, EEA/cMTO, and EEA combined with the sublabial CTM approach (EEA/CTM). Qualitative and quantitative assessments, including working distance and visualization angle to the PA, were recorded. Clinical application of EEA/cMTO is demonstrated in a lateral sphenoid sinus CSF leak repair. RESULTS: During the qualitative assessment, multiport EEA/cMTO provides superior visualization from a high vantage point and better instrument maneuverability than multiport EEA/CTM for the PA and retrocarotid CCS, while maintaining a similar lateral trajectory. The cMTO approach has significantly shorter working distances to all three target areas compared with the CTM approach and EEA. The mean distances to the LRSS, PA, and retrocarotid CCS were 50.69 ± 4.28 mm (p < 0.05), 67.11 ± 5.05 mm (p < 0.001), and 50.32 ± 3.6 mm (p < 0.001), respectively. The mean visualization angles to the PA obtained by multiport EEA/cMTO and EEA/CTM were 28.4° ± 3.27° and 24.42° ± 5.02° (p < 0.005), respectively. CONCLUSIONS: Multiport EEA/cMTO to the contralateral LRSS offers the advantage of preserving the pterygopalatine fossa contents and the vidian nerve, which are frequently sacrificed during a transpterygoid approach. This approach also offers superior visualization and better instrument maneuverability compared with EEA/CTM for targeting the petroclival region and retrocarotid CCS.

Contralateral Nasofrontal Trephination: A Novel Corridor for a "Dual Port" Approach to the Petrous Apex.

BACKGROUND AND OBJECTIVES: Expanded endonasal approaches (EEAs) have proven safe and effective in treating select petrous apex (PA) pathologies. Angled endoscopes and instruments have expanded indications for such approaches; however, the complex neurovascular anatomy surrounding the petrous region remains a significant challenge. This study evaluates the feasibility, anatomic aspects, and limitations of a contralateral nasofrontal trephination (CNT) route as a complementary corridor improving access to the PA. METHODS: Expanded endonasal and CNT approaches to the PA were carried out bilaterally in 15 cadaveric heads with endovascular latex injections. The distance to the PA, angle between instruments through the 2 approach portals, and surgical freedom were measured and compared. RESULTS: Three-dimensional DICOM-based modeling and visualization indicate that the CNT route reduces the distance to the target located within the contralateral PA by an average of 3.33 cm (19%) and affords a significant increase in the angle between instruments (15.60°; 54%). Furthermore, the vertical vector of approach is improved by 28.97° yielding a caudal reach advantage of 2 cm. The area of surgical freedom afforded by 3 different approaches (endonasal, endonasal with an endoscope in CNT portal, and endonasal with an instrument in CNT portal) was compared at 4 points: the dural exit point of the 6th cranial nerve, jugular foramen, foramen lacerum, and petroclival fissure. The mean area of surgical freedom provided by both approaches incorporating the CNT corridor was superior to EEA alone at each of the surgical targets (P = <.001). CONCLUSION: The addition of a CNT portal provides an additional avenue to expand on the classical EEA to the PA. This study provides insight into the anatomic nuances and potential clinical benefits of a dual-port approach to the PA.

Management of recurrent giant hemangiopericytoma: illustrative cases.

BACKGROUND: Hemangiopericytoma (HPC) is a rare malignancy accounting for 0.4% of intracranial tumors. HPCs are characterized by local aggressiveness, high rates of recurrence, and a tendency to metastasize to extracranial sites. These features make management of HPCs challenging, often requiring a combination of radical resection and radiation. Given their rarity, optimal treatment algorithms remain undefined. OBSERVATIONS: The authors report a series of four patients who underwent resection of intracranial HPC. Mean age at presentation was 49.3 years. Three patients had reoperation for progression of residual tumor, and one patient was surgically retreated for recurrence. One patient received adjuvant radiotherapy following initial resection, and three patients received adjuvant radiotherapy following resection of recurrent or residual disease. There was one death in the series. Average progression-free survival and overall survival following the index procedure were 32.8 and 82 months, respectively. Progression occurred locally in all patients, with metastatic recurrence in one patient. LESSONS: The current gold-standard treatment for intracranial HPC consists of gross-total resection followed by radiation therapy. This approach allows satisfactory local control; however, given the tendency for these tumors to recur either locally or distally within or outside of the central nervous system, there is a need for salvage therapies to improve long-term outcomes for patients.

A tough bioadhesive hydrogel supports sutureless sealing of the dural membrane in porcine and ex vivo human tissue.

Complete sequestration of central nervous system tissue and cerebrospinal fluid by the dural membrane is fundamental to maintaining homeostasis and proper organ function, making reconstruction of this layer an essential step during neurosurgery. Primary closure of the dura by suture repair is the current standard, despite facing technical, microenvironmental, and anatomic challenges. Here, we apply a mechanically tough hydrogel paired with a bioadhesive for intraoperative sealing of the dural membrane in rodent, porcine, and human central nervous system tissue. Tensile testing demonstrated that this dural tough adhesive (DTA) exhibited greater toughness with higher maximum stress and stretch compared with commercial sealants in aqueous environments. To evaluate the performance of DTA in the range of intracranial pressure typical of healthy and disease states, ex vivo burst pressure testing was conducted until failure after DTA or commercial sealant application on ex vivo porcine dura with a punch biopsy injury. In contrast to commercial sealants, DTA remained adhered to the porcine dura through increasing pressure up to 300 millimeters of mercury and achieved a greater maximum burst pressure. Feasibility of DTA to repair cerebrospinal fluid leak in a simulated surgical context was evaluated in postmortem human dural tissue. DTA supported effective sutureless repair of the porcine thecal sac in vivo. Biocompatibility and adhesion of DTA was maintained for up to 4 weeks in rodents after implantation. The findings suggest the potential of DTA to augment or perhaps even supplant suture repair and warrant further exploration.

Endoscopic endonasal decompression of the optic nerve in the setting of compressive lesions: how I do it.

BACKGROUND: Many lesions in the anterior skull base may compress the optic nerve (ON), leading to vision loss, and even irreversible blindness. Although decompression of the optic nerve has traditionally been achieved transcranially, the endoscopic endonasal approach (EEA) is gaining traction as a minimally invasive approach recently. METHOD: We describe the key steps of an EEA ON decompression. The relevant surgical anatomy with illustration is described. Additionally, a video detailing our technique and instruments on an illustrative case is provided. CONCLUSION: Endoscopic endonasal approach ON decompression with a straight feather blade is a feasible, minimally invasive procedure to decompress the ON in the setting of anterior skull base mass lesions.

Fully Endoscopic Minimally Invasive Trans-Eyebrow Supraorbital Translaminar Approach to Third Ventricle Craniopharyngiomas: Technical Nuances and Stepwise Illustrative Description.

BACKGROUND: Traditional microsurgical approaches for addressing intraventricular craniopharyngioma provide limited access to the retrochiasmatic area and tumors with significant lateral or rostrocaudal extensions. Extended endoscopic endonasal approaches can effectively overcome many of limitations, yet they require a favorable working angle between the optic chiasm and pituitary gland, as well as the involvement of the third ventricle floor by the tumor. METHODS: Herein, the authors describe the surgical nuances of a keyhole technique for resecting third ventricle craniopharyngiomas via a fully endoscopic minimally invasive trans-eyebrow supraorbital translaminar approach (ESOTLA). A case description detailing the key surgical steps and application of the approach is provided, along with a series of cadaveric photographs to highlight the relevant anatomy and step-by-step dissection process. RESULTS: The patient is a 44-year-old man who presented with polyuria, low urine specific gravity, and panhypopituitarism. Brain magnetic resonance imaging revealed a solid-cystic heterogeneous-enhanced retrochiasmatic mass within the third ventricle, consistent with craniopharyngioma. A 1-stage ESOTLA was indicated based on the narrow pituitary-chiasm angle and the high functional status of the patient. Near-total resection was achieved, and no new postoperative neurologic or endocrine change was observed. Targeted therapy was implemented based on the histologic result, and the most recent surveillance magnetic resonance imaging showed no evidence of the residual tumor. CONCLUSIONS: By combining a keyhole approach with variable-angle endoscopic visualization through a smaller bony and soft tissue exposure, ESOTLA can provide enhanced illumination within the third ventricle, potentially addressing cosmetic concerns and limited exposure area/angle of freedom associated with its conventional microsurgical counterpart.

Instant tough adhesion of polymer networks.

Generating strong rapid adhesion between hydrogels has the potential to advance the capabilities of modern medicine and surgery. Current hydrogel adhesion technologies rely primarily on liquid-based diffusion mechanisms and the formation of covalent bonds, requiring prolonged time to generate adhesion. Here, we present a simple and versatile strategy using dry chitosan polymer films to generate instant adhesion between hydrogel-hydrogel and hydrogel-elastomer surfaces. Using this approach we can achieve extremely high adhesive energies (>3,000 J/m2), which are governed by pH change and non-covalent interactions including H-bonding, Van der Waals forces, and bridging polymer entanglement. Potential examples of biomedical applications are presented, including local tissue cooling, vascular sealing, prevention of surgical adhesions, and prevention of hydrogel dehydration. We expect these findings and the simplicity of this approach to have broad implications for adhesion strategies and hydrogel design.

Management of frontoethmoidal osteoma causing pneumocephalus and cerebrospinal fluid leakage with minimally invasive techniques: illustrative cases.

BACKGROUND: Osteoid osteoma is a common benign bone tumor frequently seen in the frontoethmoid region. However, involvement of the skull base is rare, with few cases previously reported. OBSERVATIONS: The authors report two cases of spontaneous, symptomatic frontoethmoidal osteoma: one presented with neurological deficit secondary to tension pneumocephalus and the other with cerebrospinal fluid leakage. The first case was managed with a transfrontal sinus craniotomy and pneumocephalus decompression with osteoma resection and skull base reconstruction. The second case was managed with a uninaral endoscopic endonasal approach to the anterior skull base with osteoma resection and reconstruction. LESSONS: Given the paucity of cases with associated tension pneumocephalus described in the literature, it was relevant to describe the authors' experience with surgical decision-making and the expected outcomes among patients with this pathology when using minimally invasive techniques.

Supraorbital Eyebrow Approach for Translamina Terminalis Resection of Third Ventricle Metastasis: 2-Dimensional Operative Video.

Tumors involving the third ventricle are rare, accounting for 0.6%-0.9% of all brain tumors. This deep-seated cavity is surrounded by critical neurovascular structures, making safe surgical resection of lesions in this region challenging. Traditionally, tumors of the third ventricle have been approached through a craniotomy and microsurgical resection.1-4 The supraorbital keyhole approach is a minimally invasive technique that can be used with minimal retraction of the brain and limited craniotomy while establishing a surgical field comparable with what can be achieved using traditional transcranial approaches. In this video, we describe the case of a 54-year-old man who underwent a supraorbital eyebrow approach for translamina terminalis resection of papillary thyroid carcinoma metastasis to the third ventricle. A gross total resection was achieved. The results achieved in our series are comparable with previously published reports of patients who underwent surgical resection of metastatic lesions involving the third ventricle.5-11 The patient consented to the procedure and to the publication of his image.

Successful treatment of medically and surgically refractory lymphocytic hypophysitis with fractionated stereotactic radiotherapy: a single-center experience and systematic literature review.

PURPOSE: To explore the potential role of focused radiotherapy in managing the lymphocytic hypophysitis (LH) refractory to medical therapy and surgery. METHOD: A systematic literature review was conducted following PRISMA guidelines to identify the studies on radiation treatment for hypophysitis, along with the experience in our institution. RESULTS: The study included eight patients, three from our institution and five from existing literature. The age at presentation ranged from 37 to 75 years old, with a median age of 58. The presenting symptoms involved headache in seven patients and diplopia in two patients. Pre-radiation visual field defects were noticed in four patients. All patients exhibited variable degrees of hypopituitarism before radiation, with oral corticosteroids being the initial medical treatment. Immunosuppressive therapy was attempted in two patients prior to radiation. Seven patients had a history of transsphenoidal surgery with a histologically confirmed LH. Three patients underwent stereotactic radiosurgery (SRS), while the remaining received FSRT, with a mean irradiation volume of 2.2 cm3. A single-session total dose of 12 -15 Gy was administered in the SRS group. In the FSRT group, doses ranged from 24 to 30 Gy with a median dose of 25 Gy, delivered in 2 Gy fractions. Four patients achieved a resolution of visual field defects, while another two patients demonstrated improvement in their associated focal neurologic deficits. No change in pre-existing endocrine status was shown after radiation, except in one patient. Clinical response was achieved in seven patients after a single course of radiation, while one patient required the second course. Six patients remained stable on low-dose glucocorticoid during at least a 12-month follow-up period, and one discontinued it entirely without experiencing relapse. Three patients demonstrated a complete radiologic response, while the remaining showed a partial radiologic response. CONCLUSIONS: Focused radiation, including FSRT, can play a role in symptomatic relief, effective mass shrinkage, and minimizing radiation exposure to critical surrounding structures in patients with refractory LH. However, further research efforts are necessary to better clarify its effects and optimal dose planning.

The infundibulochiasmatic angle and the favorability of an endoscopic endonasal approach in type IV craniopharyngioma: illustrative case.

BACKGROUND: Lesions located in the floor of the third ventricle are among the most difficult to access in neurosurgery. The neurovascular structures can limit transcranial exposure, whereas tumor extension into the third ventricle can limit visualization and access. The midline transsphenoidal route is an alternative approach to tumor invading the third ventricle if the tumor is localized at its anterior half and a working space between the optic apparatus and the pituitary infundibulum exists. The authors introduce the "infundibulochiasmatic angle," a valuable measurement supporting the feasibility of the translamina terminalis endoscopic endonasal approach (EEA) for resection of type IV craniopharyngiomas. OBSERVATIONS: Due to a favorable infundibulochiasmatic angle measurement on preoperative magnetic resonance imaging (MRI), an endoscopic endonasal transsellar transtubercular approach was performed to resect a type IV craniopharyngioma. At 2-month follow-up, the patient's neurological exam was unremarkable, with improvement in bitemporal hemianopsia. Postoperative MRI confirmed gross-total tumor resection. LESSONS: The infundibulochiasmatic angle is a radiological tool for evaluating the feasibility of EEA when resecting tumors in the anterior half of the third ventricle. Advantages include reduced brain retraction and excellent rates of resection, with minimal postoperative risks of cerebrospinal fluid leakage and permanent pituitary dysfunction.

Intradural Pituitary Hemitransposition: Technical Note and Case Series Illustration.

BACKGROUND AND OBJECTIVES: Lesions located in the retrosellar region, interpeduncular cistern, and petroclival region are among the most difficult to access in neurosurgery. Transcranial approaches are useful; however, the large distance between the surgeon and the lesion as well as the presence of major neurovascular structures surrounding the lesion may limit surgical exposure. A midline transsphenoidal route avoids transgression of the neurovascular plane and provides direct access to the interpeduncular cistern. To safely access the interpeduncular fossa, it requires mobilization of the pituitary gland. The pituitary hemitransposition technique permits mobilization of the gland, while preserving its venous drainage and arterial supply to the gland on one of its sides, preserving gland function. The authors aim to describe the intradural pituitary hemitransposition technique and to demonstrate its safe application for resection of skull base tumors in the retrosellar space. METHODS: The authors describe the surgical technique and illustrate its application in 5 cases of different types of skull base tumors, including a video demonstrating all the steps to perform this approach. In addition, the authors discuss the advantages and limitations of this technique compared with other approaches to the retrosellar space. RESULTS: The intradural pituitary hemitransposition technique was used to safely resect a chondrosarcoma, chordoma, craniopharyngioma, teratoma, and meningioma involving the parasellar and retrosellar spaces, while minimizing endocrine morbidity. We had one patient with mild, albeit permanent hyperprolactinemia and hypothyroidism after surgery. No other patients had permanent dysfunction related to surgery. CONCLUSION: The endonasal endoscopic intradural pituitary hemitransposition approach is an effective technique for resection of lesions located within the retrosellar and petroclival regions, allowing adequate exposure while potentially optimizing the preservation of the pituitary function.

A New Finding on Magnetic Resonance Imaging for Diagnosis of Hemifacial Spasm with High Accuracy and Interobserver Correlation.

Among patients with clinical hemifacial spasm (HFS), imaging exams aim to identify the neurovascular conflict (NVC) location. It has been proven that the identification in the preoperative exam increases the rate of surgical success. Despite the description of specific magnetic resonance image (MRI) acquisitions, the site of neurovascular compression is not always visualized. The authors describe a new MRI finding that helps in the diagnosis of HFS, and evaluate the sensitivity, specificity, and interobserver correlation of the described sign. A cross-sectional study including cases of hemifacial spasm treated surgically from 1 August 2011 to 31 July 2021 was performed. The MRIs of the cases were independently evaluated by two experienced neuroradiologists, who were blinded regarding the side of the symptom. The neuroradiologists were assigned to evaluate the MRIs in two separate moments. Primarily, they evaluated whether there was a neurovascular conflict based on the standard technique. Following this initial analysis, the neuroradiologists received a file with the description of the novel sign, named Prevedello Sign (PS). In a second moment, the same neuroradiologists were asked to identify the presence of the PS and, if it was present, to report on which side. A total of 35 patients were included, mostly females (65.7%) with a mean age of 59.02 (+0.48). Since the 35 cases were independently evaluated by two neuroradiologists, a total of 70 reports were included in the analysis. The PS was present in 66 patients (sensitivity of 94.2%, specificity of 91.4% and positive predictive value of 90.9%). When both analyses were performed in parallel (standard plus PS), the sensitivity increased to 99.2%. Based on the findings of this study, the authors conclude that PS is helpful in determining the neurovascular conflict location in patients with HFS. Its presence, combined with the standard evaluation, increases the sensitivity of the MRI to over 99%, without increasing risks of harm to patients or resulting in additional costs.

Endoscopic endonasal marsupialization of rathke cleft cysts: clinical outcomes and risk factors analysis of visual impairment, pituitary dysfunction, and CSF leak.

OBJECTIVE: This paper assesses the clinical and imaging characteristics, histopathological findings, and treatment outcomes of patients with Rathke's cleft cyst (RCC), as well as identifies potential risk factors for preoperative visual and pituitary dysfunction, intraoperative cerebrospinal fluid (CSF) leak, and recurrence. Through analyzing these factors, the study aims to contribute to the current understanding of the management of RCCs and identify opportunities for improving patient outcomes. METHODS: We performed a retrospective analysis of 45 RCC patients between ages 18-80 treated by Endoscopic Endonasal Approach (EEA) and cyst marsupialization between 2010 and 2022 at a single institution. RESULTS: The median patient age was 34, and 73% were female. The mean follow-up was 70 ± 43 months. Preoperative visual impairment correlated with cyst diameter (OR = 1.41, 95% CI = 1.07 to 1.85, p-value = 0.01) and older age (OR = 1.06, 95% CI = 1.01 to 1.11, p-value = 0.02). Intraoperative CSF leaks were 11 times more likely for cysts ≥ 2 cm (OR = 11.3, 95% CI = 1.25 to 97.37, p-value = 0.03), with the odds of leakage doubling for every 0.1 cm increase in cyst size (OR = 1.41, 95% CI = 1.08 to 1.84, p-value = 0.01). Preoperative RCC appearing hypointense on T1 images demonstrated significantly higher CSF leak rates than hyperintense lesions (OR = 122.88, 95% CI = 1.5 to 10077.54, p-value = 0.03). Preoperative pituitary hypofunction was significantly more likely in patients with the presence of inflammation on histopathology (OR = 20.53, 95% CI = 2.20 to 191.45, p-value = 0.008 ) and T2 hyperintensity on magnetic resonance imaging (MRI) sequences (OR = 23.2, 95% CI = 2.56 to 211.02, p-value = 0.005). Notably, except for the hyperprolactinemia, no postoperative improvement was observed in pituitary function. CONCLUSION: Carefully considering risk factors, surgeons can appropriately counsel patients and deliver expectations for complications and long-term results. In contrast to preoperative visual impairment, preoperative pituitary dysfunction was found to have the least improvement post-surgery. It was the most significant permanent complication, with our data indicating the link to the cyst signal intensity on T2 MR and inflammation on histopathology. Earlier surgical intervention might improve the preservation of pituitary function.

Attitudes Toward Surgical Innovation Research in the Pediatric Surgery Fellowship Match.

INTRODUCTION: Pediatric surgery applicants are increasingly pursuing research in non-traditional fields including surgical innovation. This study aims to evaluate the relative value that pediatric surgeons involved in fellow selection place on innovation experience compared to traditional research. METHODS: A cross-sectional web-based survey of American Pediatric Surgical Association members involved in the selection of pediatric surgical fellows was conducted. Respondents reported their own innovation experience and were asked to identify valuable traits of applicants who completed an innovation fellowship. They rated the value of traditional research metrics including publications, presentations, and advanced degrees compared to patents and other innovation-related metrics. Comparisons were made between those with and without innovation experience with respect to gender, years in practice, and institutional role. RESULTS: One hundred thirty respondents were involved in pediatric surgery fellow selection. Innovation work was felt to be equal to or more valuable than basic science by 75% of respondents (84% vs. clinical/outcomes, 93% vs. other non-traditional, 72% vs. other clinical fellowships). Commonly cited concerns included "fewer publications" (21%) and "preoccupation with financial reward" (19%). The most valuable innovation-related metrics were "developing a novel surgical procedure" (67%) and "developing a novel device" (58%). When asked if the respondent would advise a junior resident to pursue an innovation fellowship, 49% would, 9% would not, and 43% were unsure. Seventeen percent expressed concern for match success. CONCLUSION: Innovation experience is generally viewed positively by pediatric surgeons involved in fellow selection. However, applicants and mentors would benefit from focusing on traditional academic outputs to ensure competitiveness. TYPE OF STUDY: Cross-sectional observational study. LEVEL OF EVIDENCE: III.

Endoscopic ultrasound guided resection of a Cushing's adenoma invading the medial cavernous sinus wall using the "interdural peeling" technique.

Cushing's adenoma invading the cavernous sinus requires aggressive resection to be cured. MRI is frequently inconclusive for identifying microadenomas, and visualizing the involvement of the medial cavernous sinus is even more challenging. In this video, the authors present a patient with an adrenocorticotropic hormone (ACTH)-producing microadenoma with doubtful left medial cavernous sinus involvement on MRI. She underwent an endoscopic endonasal exploration of the medial compartment of the cavernous sinus. The abnormally thickened wall, confirmed by intraoperative endoscopic endonasal ultrasound, was safely excised using the "interdural peeling" technique. Complete resection of the tumor resulted in normalization of her postoperative cortisol levels and disease remission with no complications. The video can be found here: https://stream.cadmore.media/r10.3171/2023.4.FOCVID22150.

Endoscopic Endonasal Transpterygoid Approach: Technical Lessons.

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: The endoscopic endonasal transpterygoid approach (EETPA) provides direct access to the petrous apex, lateral clivus, inferior cavernous sinus compartment, jugular foramen, and infratemporal fossa. 1,2 In the coronal plane, it provides exposure far beyond a traditional sphenoidotomy. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: The pterygoid process of the sphenoid bone forms the junction between the body and greater sphenoid wing before bifurcating because it descends into medial and lateral plates. The key to this exposure lies in the region's bony foramina: the palatovaginal canal, vidian canal, and foramen rotundum. 3. ESSENTIALS STEPS OF THE PROCEDURE: After performing a maxillary antrostomy, stepwise exposure of these foramina leads to the pterygopalatine fossa. The sphenopalatine artery is cauterized as it becomes the posterior septal artery at the sphenopalatine foramen, and the maxillary sinus' posterior wall is opened to expose the pterygopalatine fossa. After mobilizing and retracting the contents of the pterygopalatine fossa, the pterygoid process is removed, improving access in the coronal plane. 4. PITFALLS/AVOIDANCE OF COMPLICATIONS: Vidian neurectomy causes decreased or absent lacrimation. Injury to the maxillary nerve or its branches results in facial, palatal, or odontogenic anesthesia or neuralgia. In addition, the EEPTA precludes the ability to raise an ipsilateral nasal septal flap, making it crucial to plan reconstruction preoperatively. 4,5. VARIANTS AND INDICATIONS FOR THEIR USE: There are 5 variants of the EEPTA: extended pterygopalatine fossa, lateral recess of the sphenoid sinus, petrous apex, infratemporal fossa and petrous carotid artery, and middle and posterior skull base. 5The patient consented to the procedure.Images in the video used with permission as follows: images at 0:33 and 1:15 reused from Bozkurt et al, 3 © Georg Thieme Verlag KG; image at 0:39 from Prosser et al, 5 © John Wiley and Sons; images at 0:54, 9:03, and 9:38 from Kasemsiri et al, 1 © John Wiley and Sons; images at 1:07 and 9:44 from Falcon et al, 2 © John Wiley and Sons; image at 1:15 from Sandu et al, 4 © Springer Nature.

A silent corticotroph adenoma: making the case for a pars intermedia origin. Illustrative case.

BACKGROUND: Silent corticotroph adenomas (SCAs) are the only pituitary adenomas thought to originate from the pars intermedia. This case report presents the rare finding of a multimicrocystic corticotroph macroadenoma displacing the anterior and posterior lobes of the pituitary gland on magnetic resonance imaging (MRI). This finding supports the hypothesis that silent corticotroph adenomas may originate from the pars intermedia and should be considered in the differential for tumors arising from this location. OBSERVATIONS: A 55-year-old man presented with an episode of confusion and blurred vision. MRI demonstrated separation of the anterior and posterior glands by a solid-cystic lesion located within the pars intermedia that superiorly displaced the optic chiasm. Endocrinologic evaluation was unremarkable. The differential diagnosis included pituitary adenoma, Rathke cleft cyst, and craniopharyngioma. The tumor was confirmed to be an SCA on pathology and was completely removed through the endoscopic endonasal transsphenoidal approach. LESSONS: The case highlights the importance of preoperative screening for subclinical hypercortisolism for tumors arising from this location. Knowledge of a patient's preoperative functional status is critical and dictates their postoperative biochemical assessment to determine remission. The case also illustrates surgical strategies for resecting pars intermedia lesions without injuring the gland.

Endoscopic Endonasal Transcavernous Posterior Clinoidectomy With Inferior Hypophyseal Artery Preservation for a Cavernous Sinus Hemangioma: Technical Case Report.

BACKGROUND AND IMPORTANCE: Unilateral inferior hypophyseal artery (IHA) sacrifice is routinely performed during endoscopic endonasal transcavernous interdural posterior clinoidectomy. However, unilateral IHA sacrifice presents the risk of temporary postoperative diabetes insipidus. We present a case demonstrating the feasibility of endoscopic endonasal transcavernous posterior clinoidectomy without IHA sacrifice. CLINICAL PRESENTATION: A 62-year-old man presented with progressive weakness of his left oculomotor and abducens nerves. MRI of the brain revealed a small lesion suspicious for hemangioma in the posterior compartment of the left cavernous sinus. Following an endoscopic endonasal transcavernous approach using the interdural peeling technique, an IHA-sparing posterior clinoidectomy was performed to provide access to the tumor in the posterior cavernous sinus. After complete resection, the patient's symptoms improved and a diagnosis of cavernous sinus hemangioma was confirmed by histopathology. CONCLUSION: Unilateral IHA preservation may be performed safely when performing a transcavernous interdural posterior clinoidectomy. IHA preservation can be readily achieved if the artery is redundant, the lesion is small and located in the posterior cavernous sinus, and there is a short posterior clinoid, ultimately avoiding the risk of transient postoperative diabetes insipidus.