Transcranial Approach Research Articles

Introducing next-generation transcranial surgery with the head-mounted 3D View Vision display in extracorporeal microsurgery: illustrative cases.

Exoscopy in neurosurgery offers various advantages, including increased freedom of the viewing axis while the surgeon maintains a comfortable upright position. However, the optimal monitor positioning to avoid interference with surgical manipulation remains unresolved. Herein, the authors describe two cases in which a three-dimensional head-mounted display (3D-HMD) was introduced into a transcranial neurosurgical procedure using an exoscope. Case 1 was a 50-year-old man who presented with recurrent epistaxis and was diagnosed with an olfactory neuroblastoma that extended from the nasal cavity to the anterior cranial base and infiltrated the right anterior cranial fossa. Case 2 was a 65-year-old man who presented with epistaxis and was diagnosed with a left-sided olfactory neuroblastoma. In both cases, en bloc tumor resection was successfully performed via a simultaneous exoscopic transcranial approach using a 3D-HMD and an endoscopic endonasal approach, eliminating the need to watch a large monitor beside the patient. This is the first report of using a 3D-HMD in transcranial surgery. The 3D-HMD effectively addressed issues with the field of vision and concentration while preserving the effectiveness of traditional microscopic and exoscopic procedures when observed on a 3D monitor. Combining the 3D-HMD with an exoscope holds the potential to become a next-generation surgical approach.

Olfactory groove meningiomas: supraorbital keyhole versus orbitofrontal, frontotemporal, or bifrontal approaches.

Olfactory groove meningiomas (OGMs) often require surgical removal. The introduction of recent keyhole approaches raises the question of whether these tumors may be better treated through a smaller cranial opening. One such approach, the supraorbital keyhole craniotomy, has never been compared with more traditional open transcranial approaches with regard to outcome. In this study, the authors compared clinical, radiographic, and functional quality of life (QOL) outcomes between the keyhole supraorbital approach (SOA) and traditional transcranial approach (TTA) for OGMs. They sought to examine the potential advantages and disadvantages of open/TTA versus keyhole SOA for the resection of OGMs in a relatively case-matched series of patients. A retrospective, single-institution review of 57 patients undergoing a keyhole SOA or larger traditional transcranial (frontotemporal, pterional, or bifrontal) craniotomy for newly diagnosed OGMs between 2005 and 2023 was performed. Extent of resection, olfaction, length of stay (LOS), radiographic volumetric assessment of postoperative vasogenic and cytotoxic edema, and QOL (using the Anterior Skull Base Questionnaire) were assessed. Thirty-two SOA and 25 TTA patients were included. The mean EOR was not significantly different by approach (TTA: 99.1% vs SOA: 98.4%, p = 0.91). Olfaction was preserved or improved at similar rates (TTA: 47% vs SOA: 43%, p = 0.99). The mean LOS was significantly shorter for SOA patients (4.1 ± 2.8 days) than for TTA patients (9.4 ± 11.2 days) (p = 0.002). The authors found an association between an increase in postoperative FLAIR cerebral edema and TTA (p = 0.031). QOL as assessed by the ASQB at last follow-up did not differ significantly between groups (p = 0.74). The keyhole SOA was associated with a statistically significant decrease in LOS and less postoperative edema relative to traditional open approaches.

Pterional approach for tuberculum sellae meningiomas: a 17-year single-center experience.

Tuberculum sellae meningiomas (TSMs) are typically in the proximity of the optic nerves and the optic chiasm, thus making the primary aim of surgery the enhancement or stabilization of the patients' visual acuity. The authors therefore undertook a retrospective review of their 17-year experience with the pterional approach to ascertain the resection rate, neurological outcome, and visual outcome. Patients who underwent TSM surgery between September 2003 and December 2020 at the authors' institution were retrospectively evaluated. Patient demographics, tumor characteristics, surgical parameters, postoperative visual outcomes, and complications were analyzed. Gross-total resection (GTR) and subtotal resection (STR) rates were assessed, along with the impact of surgical approach on visual outcomes. A total of 71 patients with a mean age of 56.9 ± 14.3 years were enrolled in the study. The mean tumor volume was 10.2 ± 12.8 cm3. Postoperatively, 38.7% of patients experienced visual improvement, 45.2% had stable visual acuity, and 16.1% showed visual deterioration. Ipsilateral or contralateral surgical approaches were performed based on the side of the most affected visual acuity. No significant difference in postoperative visual outcomes was observed between the two approaches. GTR was achieved in 84.0% and STR in 16.0%. Minor complications occurred in 3 patients (4.2%), while major complications were found in 4 patients (5.6%). Seven patients (9.8%) showed recurrent tumor growth after 53 months. Progression-free survival after GTR was 123.9 ± 12.9 months, and it was 59.3 ± 13.2 months after STR. This study highlighted the finding that TSMs can be successfully resected using a transcranial pterional approach with a low risk of complications and sufficient visual outcomes. Further studies with larger sample sizes are warranted to confirm these findings and optimize surgical strategies for TSM resection.

SURG-33. LATERAL VERSUS MIDLINE APPROACHES TO RESECTION OF SKULL BASE CHORDOMAS: A META-ANALYSIS

Abstract INTRODUCTION Though it remains a rare and devastating tumor, great strides have been taken to improve prognostication and treatment paradigms for patients with skull base chordoma. With respect to surgical techniques, lateral transcranial (TC) approaches have traditionally been used, however endoscopic endonasal approaches (EEA) have been advocated for midline lesions. However, due to the rarity of this tumor (0.2% of all intracranial neoplasms), investigations within the literature remain limited to small retrospective series. METHODS Accordingly, we performed a systematic review and meta-analysis in order to profile surgical outcomes for midline versus lateral approaches to resection of skull base chordoma. Meta-analysis of pooled mortality rates and sub-analyses of operative margin and surgical complications were used to compare midline versus lateral approaches via the Mantel-Haenszel method. We considered all p-values < 0.05 to be statistically significant. RESULTS Fifty studies published between 1993-2022 reporting data for 2252 patients remained eligible for analysis. Average age at diagnosis was 42.4 ± 12.5 years, while average age of treatment initiation was 43.0 ± 10.6 years. The relative risk for mortality (Figure 2) in patients undergoing surgical intervention was -0.93 [-1.03,-0.97], I^2=95%, (p < 0.001), indicating low surgery-related mortality rates. From the seven studies eligible for formal meta-analysis, we found that there was no statistically significant difference between midline and lateral approaches with respect to rates of GTR or recurrence. Nor was there a significant difference between rates of postoperative cranial nerve dysfunction, although the result trended toward favoring midline approaches. Finally, midline approaches exhibited a lower odds for peri- and post-operative complications, including CSF leak (OR 0.59 [0.35, 0.97], I^2 = 0%, p = 0.04). CONCLUSION Ultimately, there are no striking differences between midline versus lateral approaches to resection of skull base chordoma, particularly as they relate to operative margins, recurrence, or rates of cranial nerve palsy.

Surgical Clipping of Intracranial Aneurysms Using a Transcranial Neuroendoscopic Approach.

This retrospective study was performed to evaluate the feasibility and safety of surgically clipping intracranial aneurysms using a transcranial neuroendoscopic approach. A total of 229 patients with cerebral aneurysms were included in our study, all of whom were treated with clamping surgery at Wuhan University People's Hospital. They were divided into neuroendoscopic and microscopic groups, according to whether or not neuroendoscopy was used for the clamping surgery. We statistically analyzed the patients' baseline data, surgical outcomes, and complications, which were then evaluated to assess the treatment effect. The baseline characteristics were not statistically significant, except for gender, for which the proportions of female patients in the two groups were 69 (56.1%) and 46 (43.4%). There were no patients with incomplete aneurysm clamping or parent vessel occlusion in the neuroendoscopic group, and there were 4 (3.8%) and 2 (1.9%) in the microscopic group, respectively; however, there was no statistically significant difference in the comparison of the two groups. The mean operative times of the two groups were 181 min and 154 min, respectively, and were statistically different. However, the mRS scores of the two groups showed no significant difference in patient prognosis. The differences in complications (including limb hemiplegia, hydrocephalus, vision loss, and intracranial infection) were not statistically significant, except for cerebral ischemia, for which the proportions of patients in the two groups were 8 (6.5%) and 16 (15.1%). Neuroendoscopy can provide clear visualization and multi-angle views during aneurysm clipping, which is helpful for ensuring adequate clipping and preventing complications.

Abstract 032: Ovine Models for Cerebral Venous Catheter Access: A Single Center Experience

Introduction Large animal models are utilized for preclinical neuroendovascular research, and aid in the characterization and de‐risking of novel therapeutic approaches. To date, only a single prior study has been published providing a detailed account of an ovine model (Corriedale sheep) for cerebral venous access. The generalizability of these experiments has not yet been validated externally. In an effort to replicate these findings and de‐risk a novel, non‐surgical trans‐dural venous sinus approach to the cerebrum, cerebral venous access was attempted in 3 sheep specimens using transcranial and endovascular approaches. We report our experience validating this large animal model for translational and preclinical research. Methods 3 animal experiments were performed at the UCLA TRIC laboratory between 02/2022 and 10/2022. The sheep were anesthesitized and handled under approval of the Animal Research Committee at UCLA (protocol ARC 2020‐19). The neck and groin areas were shaved and aseptically prepped. MRI Brain and MR Brain venogram imaging was performed on a 3T Siemens Magnetom MRI. Femoral artery and external jugular vein access were obtained using the Seldinger technique under ultrasound guidance and did not require a surgical cut down. Two Suffolk and one Rambouillet sheep were used (average weight 60 kg and 40 kg, respectively). The animals were transferred to the catheter laboratory and image guidance was performed with a monoplane Siemens Artis Zeego. A transcranial approach to the dorsal sagittal sinus was attempted in one Suffolk sheep specimen utilizing a Hubly Drill and a micro‐puncture kit. An endovascular approach to the dorsal sagittal sinus was attempted in second Suffolk sheep specimen using a 25 cm, 8 Fr Pinnacle Sheath via the external jugular vein followed by a 132 cm Catalyst 5 catheter, 0.027" Medtronic Marksman, Stryker SL‐10 and Offset microcatheters assembled over 0.014" Synchro Standard and exchange‐length Choice PT microguidewires. In a third experiment, an endovascular approach to the dorsal sagittal sinus was attempted in a Rambouillet sheep specimen using a 95 cm TracStar, 115 cm Catalyst 5 catheter, and 0.027" Medtronic Marksman microcatheter assembled over 0.014" Synchro Standard and exchange‐length Boston Scientific (BS) Choice PT microguidewires. The 0.027" Marksman microcatheter was subsequently exchanged for a 2.7 French BS Stingray LP coronary CTO re‐entry microcatheter in the Rambouillet sheep, which was tracked to the anterior third of the dorsal sagittal sinus over the exchange length wire. Results A transcranial approach to the dorsal sagittal sinus was complicated by misaligned needle trajectories resulting in brain parenchymal damage. The external jugular vein was the conduit for accessing the first and second emissary veins of the retroauricular foramen (figure 2). Access to the temporal and then transverse sinuses was possible from either of the aforementioned emissary veins. Interestingly, the morphology of the dorsal sagittal sinus was bifid and each vessel channel measured between 1.65 – 1.7 mm in diameter (figure 1). Access to the temporal sinus from an endovascular approach was possible with all microcatheters. However, access with a 0.027" microcatheter beyond the torcular herophili and into the dorsal sagittal sinus was only possible in the Rambouillet sheep despite its smaller body size. Intermediate catheters (>4 Fr) could not be advanced beyond the skull base in none of the sheep breeds. Lastly, microcatheter advancement into the cerebral hemispheric space across a transdural venous sinus puncture access point deliberately created by wire perforation was feasible from the Stingray re‐entry system after exchanging for a 0.017" microcatheter. A coil (Stryker Target) was deployed extravascularly from the 0.017" microcatheter for post‐mortem characterization (figure 3). Conclusion One of three experiments met criteria for success. Due to reliance on a monoplane projection, a transcranial approach failed as an access route to the dorsal sagittal sinus resulting in iatrogenic parenchymal damage. Despite the larger body size, the second Suffolk sheep dural venous sinus system could not be catheterized beyond the skull base, likely due to the small caliber or focal stenosis of the temporal or transverse sinuses. The Rambouillet sheep breed proved to be a more adequate specimen for cerebral venous—specifically dorsal sagittal sinus—access with larger bore microcatheters. Based on this experience, careful selection of an appropriate sheep breed is necessary for modeling endovascular cerebral venous access and assessing novel procedures.

Quantitative Anatomical Comparison of Surgical Approaches to Meckel's Cave.

Meckel's cave is a challenging surgical target due to its deep location and proximity to vital neurovascular structures. Surgeons have developed various microsurgical transcranial approaches (MTAs) to access it, but there is no consensus on the best method. Newer endoscopic approaches have also emerged. This study seeks to quantitatively compare these surgical approaches to Meckel's cave, offering insights into surgical volumes and exposure areas. Fifteen surgical approaches were performed bilaterally in six specimens, including the pterional approach (PTA), fronto-temporal-orbito-zygomatic approach (FTOZA), subtemporal approach (STA), Kawase approach (KWA), retrosigmoid approach (RSA), retrosigmoid approach with suprameatal extension (RSAS), endoscopic endonasal transpterygoid approach (EETPA), inferolateral transorbital approach (ILTEA) and superior eyelid approach (SEYA). All the MTAs were performed both with 10 mm and 15 mm of brain retraction, to consider different percentages of surface exposure. A dedicated navigation system was used to quantify the surgical working volumes and exposure of different areas of Meckel's cave (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada). Microsurgical transcranial approaches were quantified with two different degrees of brain retraction (10 mm and 15 mm). Statistical analysis was performed using a mixed linear model with bootstrap resampling. The RSAS with 15 mm of retraction offered the maximum exposure of the trigeminal stem (TS). If compared to the KWA, the RSA exposed more of the TS (69% vs. 46%; p = 0.01). The EETPA and ILTEA exposed the Gasserian ganglion (GG) mainly in the anteromedial portion, but with a significant 20% gain in exposure provided by the EETPA compared to ILTEA (42% vs. 22%; p = 0.06). The STA with 15 mm of retraction offered the maximum exposure of the GG, with a significant gain in exposure compared to the STA with 10 mm of retraction (50% vs. 35%; p = 0.03). The medial part of the three trigeminal branches was mainly exposed by the EETPA, particularly for the ophthalmic (66%) and maxillary (83%) nerves. The EETPA offered the maximum exposure of the medial part of the mandibular nerve, with a significant gain in exposure compared to the ILTEA (42% vs. 11%; p = 0.01) and the SEY (42% vs. 2%; p = 0.01). The FTOZA offered the maximum exposure of the lateral part of the ophthalmic nerve, with a significant gain of 67% (p = 0.03) and 48% (p = 0.04) in exposure compared to the PTA and STA, respectively. The STA with 15 mm of retraction offered the maximum exposure of the lateral part of the maxillary nerve, with a significant gain in exposure compared to the STA with 10 mm of retraction (58% vs. 45%; p = 0.04). The STA with 15 mm of retraction provided a significant exposure gain of 23% for the lateral part of the mandibular nerve compared to FTOZA with 15 mm of retraction (p = 0.03). The endoscopic approaches, through the endonasal and transorbital routes, can provide adequate exposure of Meckel's cave, especially for its more medial portions, bypassing the impediment of major neurovascular structures and significant brain retraction. As far as the most lateral portion of Meckel's cave, MTA approaches still seem to be the gold standard in obtaining optimal exposure and adequate surgical volumes.

Combined endoscopic endonasal and transcranial approach for internal carotid artery aneurysms: usefulness and safety of endonasal proximal control.

It is necessary to secure both the proximal and distal sides of the parent artery to prevent premature rupture when clipping cerebral aneurysms. Herein, we describe four cases in which the proximal internal carotid artery (ICA), affected by a paraclinoid aneurysm, was secured using an endoscopic endonasal approach. We used various tools, including a surgical video, cadaver dissection picture, artist's illustration, and intraoperative photographs, to elucidate the process. No patient experienced postoperative complications at our institution. Compared to the cervical or cavernous ICA, the ICA adjacent to the clivus (paraclival ICA) can be anatomically safely and easily exposed using an endoscopic endonasal approach because there is no need to consider cerebrospinal fluid leakage or hemorrhage from the cavernous sinus. Securing the proximal side of the parent artery using an endoscopic endonasal approach may be a viable method for clipping selected ICA aneurysms, such as paraclinoid aneurysms especially for upward or outward aneurysms of the C2 portion.

Anteromedial Petrous (Gardner's) Triangle: Surgical Anatomy and Relevance for Endoscopic Endonasal Approach to the Petrous Apex and Petroclival Region.

Triangular corridors have been used as reliable surgical entry points for open transcranial approaches to the petrous apex (PA) and petroclival region (PCR). The endoscopic endonasal approaches have grown rapidly in the last decade, and the indications have advanced. The knowledge of accurate and reliable anatomic landmarks through endoscopic endonasal route is essential and remain to be established. The purpose of this study was to describe the feasibility and surgical exposure of the anteromedial petrous (Gardner's) triangle as a novel corridor to the PA and PCR. Five anatomic specimens were dissected. The PA and PCR were accessed through endoscopic endonasal approaches and contralateral transmaxillary approach. The limits of the anteromedial petrous (Gardner's) triangle were identified and dissected and associated measurements performed. The dissection was divided into 6 steps. The limits of the anteromedial petrous (Gardner's) triangle were identified and defined by the paraclival internal carotid artery anterolaterally, the abducens nerve posteromedially, and the petroclival synchondrosis inferiorly. Three lines were established following the limits of the triangle. The mean distance of the anterolateral limit was 10.03 mm (SD = 0.94), of the posteromedial limit was 20.06 mm (SD = 2.90), and of the inferior limit was 17.99 mm (SD = 2.99). The mean area was 87.56 mm 2 (SD = 20.06). The 3 anatomic landmarks with a critical role to safely define the triangle were the pterygosphenoidal fissure, the petrosal process of the sphenoid bone, and the petroclival synchondrosis. The anteromedial (Gardner's) triangle is a well-defined bone corridor which provides access to the entire petrous bone and petroclival junction through endoscopic endonasal route. Regardless of the anatomic variations or tumor location, the landmarks of the abducens nerve, paraclival internal carotid artery, and petroclival synchondrosis are key for understanding lateral access to tumors extending from the clivus.

THU088 Perioperative Management Of Patients With Pituitary Tumors Undergoing Surgery: A Retrospective Review

Abstract Disclosure: J.T. Batch: None. H. Belal: None. G.Y. Gandhi: None. Background: Pituitary tumors account for 10% of brain neoplasms with transsphenoidal resection of these tumors responsible for 20% of all intracranial operations performed for primary brain tumors. Hypothesis: We suspected significant heterogeneity and lack of standardized protocols in the perioperative endocrine evaluation and management of patients undergoing resection of sellar masses. Methods: From June 2016 through November 2022, we identified 46 adult patients (23 females, mean age 52 years, age range 25 to 84 years) who underwent pituitary mass resection (44 transsphenoidal and two transcranial approaches) at our institution. We abstracted information about perioperative endocrine evaluation from their medical records. Results: The vast majority (32 patients) had nonfunctioning pituitary macroadenomas. Other indications for surgery included Cushing’s disease (3), prolactinomas (2), acromegaly (3), pituitary metastasis (1), gonadotroph adenomas (2), Rathke cleft cyst (2), and epidermoid cyst (1). Preoperative cortisol level was not measured in 8 patients. The decision to administer intraoperative corticosteroids was not consistently based on preoperative cortisol levels. 24 patients had cortisol levels <11 mcg/dL; 22 received intraoperative corticosteroids at anesthesia induction. 13 patients had cortisol levels ≥11 mcg/dL, and 11 received intraoperative steroids. Two patients had very large pituitary masses (over 4 cm), and one received intraoperative corticosteroids. Of the two patients with Cushing’s disease, one received intraoperative corticosteroids. Cortisol level was checked in 27 patients in the first four weeks after surgery; in the rest, it was measured between 2 months and three years after surgery. All five patients with confirmed adrenal insufficiency with cortisol levels <3 mcg/dL were treated with corticosteroids. 22 patients had cortisol levels in the equivocal zone (3 to 15 mcg/dL), and 16 were treated with corticosteroids. Nine patients ultimately did not have a follow-up in endocrinology. The long-term permanence of the diagnosis of diabetes insipidus could not be established due to a lack of uniform follow-up testing. Conclusions: Patients with pituitary gland tumors represent a heterogeneous yet commonly encountered neurosurgical population. Successful surgical management is critically dependent on the quality of perioperative care. Understanding preoperative evaluation, intraoperative management, potential complications, their management, and strategies for avoidance are fundamental to reduce morbidity and mortality. High-quality evidence guiding perioperative practices in this population is needed. We have used the information gathered in this study to create a multidisciplinary perioperative protocol with expertise from endocrinologists, neurosurgeons, neuro-ophthalmologists, and neuroradiologists. Presentation: Thursday, June 15, 2023

CLINICAL PICTURE AND CURRENT MANAGEMENT OF PITUITARY TUMORS: A REVIEW

The pituitary is a pea-sized complex gland located below the hypothalamus at the base of skull in the sella turcica, is composed of three types of cells. Pituitary being the centre of all the stimulating hormones of various organs, its overgrowth leads to hormone excess syndromes, like acromegaly, Cushing disease, central hypothyroidism, and hyperprolactinemia etc. so studies involving pituitary tumors have mainly focused on hormone production. Pituitary Adenoma is the most common (~85%) tumor in the sellar-suprasellar region. Their prevalence is growing which has risen over the last 20 years probably due to improved imaging techniques and treatment outcomes. Due to the tumors growth in size Compression of adjacent anatomical structures especially optic nerves in close vicinity can lead to focal neurologic deficits such as diplopia, visual field defects and loss of visual acuity typically bitemporal hemianopsia. The surgical procedure of choice is a trans-sphenoidal micro surgically or endoscopically performed by a neurosurgeon leaving transcranial approach for large and invasive pituitary neoplasm with sellar remnants. Even in the case of recurrent tumor or progression of residual tumor tissue after surgery, a second operation and/or radiotherapy should be considered.

Surgical Treatment of Spheno-Orbital Meningiomas: A Systematic Review and Meta-Analysis of Surgical Techniques and Outcomes.

Spheno-orbital meningiomas (SOMs) are rare tumors arising from the meninges surrounding the sphenoid bone and orbital structures. Surgical resection is the primary treatment approach for SOMs. Several surgical approaches have been described during the decades, including microsurgical transcranial (MTAs), endoscopic endonasal (EEAs), endoscopic transorbital (ETOAs), and combined approaches, and the choice of surgical approach remains a topic of debate. This systematic review and meta-analysis aim to compare the clinical and surgical outcomes of different surgical approaches used for the treatment of SOMs, discussing surgical techniques, outcomes, and factors influencing surgical decision making. A comprehensive literature review of the databases PubMed, Ovid MEDLINE, and Ovid EMBASE was conducted for articles published on the role of surgery for the treatment of SOMs until 2023. The systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Meta-analysis was performed to estimate pooled event rates and assess heterogeneity. Fixed- and random-effects were used to assess 95% confidential intervals (CIs) of presenting symptoms, outcomes, and complications. A total of 59 studies comprising 1903 patients were included in the systematic review and meta-analysis. Gross total resection (GTR) rates ranged from 23.5% for ETOAs to 59.8% for MTAs. Overall recurrence rate after surgery was 20.7%. Progression-free survival (PFS) rates at 5 and 10 years were 75.5% and 49.1%, respectively. Visual acuity and proptosis improvement rates were 57.5% and 79.3%, respectively. Postoperative cranial nerve (CN) focal deficits were observed in 20.6% of cases. The overall cerebro-spinal fluid (CSF) leak rate was 3.9%, and other complications occurred in 13.9% of cases. MTAs showed the highest GTR rates (59.8%, 95%CI = 49.5-70.2%; p = 0.001) but were associated with increased CN deficits (21.0%, 95%CI = 14.5-27.6%). ETOAs had the lowest GTR rates (23.5%, 95%CI = 0.0-52.5%; p = 0.001), while combined ETOA and EEA had the highest CSF leak rates (20.3%, 95%CI = 0.0-46.7%; p = 0.551). ETOAs were associated with better proptosis improvement (79.4%, 95%CI = 57.3-100%; p = 0.002), while anatomical class I lesions were associated with better visual acuity (71.5%, 95%CI = 63.7-79.4; p = 0.003) and proptosis (60.1%, 95%CI = 38.0-82.2; p = 0.001) recovery. No significant differences were found in PFS rates between surgical approaches. Surgical treatment of SOMs aims to preserve visual function and improve proptosis. Different surgical approaches offer varying rates of GTR, complications, and functional outcomes. A multidisciplinary approach involving a skull base team is crucial for optimizing patient outcomes.

Extremely Rare Pathologies of the Craniovertebral Junction Region: A Case Series and Review of the Literature

Background: The craniovertebral junction is a complex region, connecting the occiput, the atlas, the axis, and the containing vital neural and vascular structures. There is a great variability in diseases involving the craniovertebral junction, of different nature, each rare in frequency. Methods: We conducted a retrospective chart review of the patients diagnosed with extremely rare pathologies of the craniovertebral junction that we have operated in the last 5 years. Results: After excluding the relatively more frequent pathologies, we identified nine cases of rare craniovertebral junction pathologies. Six were operated using an endoscopic endonasal approach, two using a far lateral transcranial approach, and one underwent a C1 hemilaminectomy. Conclusions: Diagnosis and management of the rare pathologies of the craniovertebral junction are challenging. A multidisciplinary approach is recommended for the proper management of these patients.

Effect of Optic Canal Opening on Postoperative Visual Acuity in Patients with Tuberculum Sellae Meningiomas.

Tuberculum sellae meningiomas (TSMs) account for 5 to 10% of all intracranial meningiomas. They typically invade the optic canal and displace the optic nerve upward and laterally. The transcranial approach has been the standard surgical approach, while the transsphenoidal approach has been proposed for its minimally invasive nature; however, some reservations concerning this approach remain. From January 2000 to December 2018, a total of 97 patients who were diagnosed with TSM with invasion of the optic canal were enrolled and underwent microsurgery for tumor removal with optic canal opening. A retrospective analysis was performed on the effect of optic canal opening on postoperative visual acuity improvement. The median follow-up was 17.4 months (range: 3-86 months). Among the 97 patients with TSM involving the optic canal, optic canal invasion was seen on preoperative imaging in 73 patients and during intraoperative exploration in all patients. In total, 87/97 patients (89.7%) underwent optic canal opening to remove tumors involving the optic canal, and the rate of total macroscopic resection of tumors invading the optic canal was 100%. Among the 10 patients who did not undergo optic canal opening, the rate of total resection of tumors involving the optic canal was 80% (8/10, p < 0.001). There were no deaths or serious complications. The postoperative visual acuity improvement rate was 64.4%, 23.7% maintained the preoperative level, and the visual acuity deteriorated 11.9%. Intraoperative optic canal opening is the key to total resection of TSMs involving the optic canal and improving postoperative visual acuity.

Nuclear translocation of beta catenin in patients with Rathke cleft cysts—clinical and imaging characteristics and risk of recurrence

PurposeAlthough Rathke cleft cysts (RCC) are benign lesions of the sellar region, recurrence is frequent after surgical treatment. Nuclear translocation of ß-catenin (NTßC), a key effector of the wnt-signaling pathway that is responsible for cell renewal, has been shown to act as a proto-oncogene and is considered to be a potential risk factor for increased recurrence in RCC. In this study, we analyzed a surgically treated cohort into patients with and without NTßC expression in order to identify clinical and imaging differences and further evaluate the risk of recurrence.MethodsPatients with resection of RCC between 04/2001 and 11/2020 were included. Histological specimens were immunohistochemically stained for ß-catenin. Study endpoints were time to cyst recurrence (TTR) and functional outcome. Functional outcome included ophthalmological and endocrinological data. Furthermore, MRI data were assessed.ResultsSeventy-three patients (median age 42.3 years) with RCC underwent mainly transsphenoidal cyst resection (95.9%), 4.1% via transcranial approach. Immunohistochemical staining for ß-catenin was feasible in 61/73 (83.6%) patients, with nuclear translocation detected in 13/61 cases (21.3%). Patients with and without NTßC were equally likely to present with endocrine dysfunction before surgery (p = 0.49). Postoperative new hypopituitarism occurred in 14/73 (19.2%) patients. Preoperative visual impairment was equal in both groups (p = 0.52). Vision improved in 8/21 (33.3%) patients and visual field deficits in 22/34 (64.7%) after surgery. There was no difference in visual and perimetric outcome between patients with and without NTßC (p = 0.45 and p = 0.23, respectively). On preoperative MRI, cyst volume (9.9 vs. 8.2 cm3; p = 0.4) and evidence of hemorrhage (30.8% vs. 35.4%; p = 0.99) were equal and postoperative cyst volume decreased significantly in both groups (0.7 vs. 0.5 cm3; p < 0.0001 each). Cyst progression occurred in 13/73 (17.8%) patients after 39.3 ± 60.3 months. Cyst drainage with partial removal of the cyst wall resulted in improved recurrence-free survival without increasing the risk of complications compared with cyst fenestration alone. Patients with postoperative diabetes insipidus had an increased risk for recurrence according to multivariate analysis (p = 0.005). NTßC was evident in 4/15 patients (26.7%) and was not associated with a higher risk for recurrence (p = 0.67).ConclusionTransnasal transsphenoidal cyst drainage with partial removal of the cyst wall reduces the risk of recurrence without increasing the risk of complications compared with fenestration of the cyst alone. Patients with postoperative diabetes insipidus seem to have an increased risk for recurrence. In contrast, NTßC was not associated with a higher risk of recurrence and did not provide stratification for clinically distinct patients.

Endoscopic Endonasal Transplanum-Transtuberculum Approach for Pituitary Adenomas/PitNET: 25 Years of Experience.

The role of the endoscopic transplanum-transtuberculum approach (ETTA) in the treatment of pituitary adenomas/PitNETs (PAs) is sparsely analyzed in the literature, and its use is still debated in the current practice. The aim of this study was to report our experience with this approach. Our institutional registry was retrospectively reviewed, and patients who underwent ETTA for a PA from 1998 to 2022 were included. Fifty-seven cases were enrolled over a time span of 25 years, corresponding to 2.4% of our entire PA caseload. Radical resection was achieved in 57.9% of cases, with re-do surgery (p = 0.033) and vessel encasement/engulfment (p < 0.001) as predictors of partial resection. CSF leak incidence stood at 8.8%, with higher BMI (p = 0.038) as its only significant predictor. Partial or full improvement of the visual field deficits was achieved in 73.5% of cases. No surgical mortality was observed. According to our results, ETTA for the treatment of PAs is characterized by a satisfactory surgical outcome but with greater morbidity than the conventional endoscopic approach. Therefore, it should be reserved for the few selected cases otherwise unsuitable for the endoscopic trans-sphenoidal route, representing a valid alternative and an effective complementary route for the transcranial approach for these challenging PAs.

International Tuberculum Sellae Meningioma Study: Preoperative Grading Scale to Predict Outcomes and Propensity-Matched Outcomes by Endonasal Versus Transcranial Approach.

Tuberculum sellae meningiomas are resected via an expanded endonasal (EEA) or transcranial approach (TCA). Which approach provides superior outcomes is debated. The Magill-McDermott (M-M) grading scale evaluating tumor size, optic canal invasion, and arterial involvement remains to be validated for outcome prediction. The objective of this study was to validate the M-M scale for predicting visual outcome, extent of resection (EOR), and recurrence, and to use propensity matching by M-M scale to determine whether visual outcome, EOR, or recurrence differ between EEA and TCA. Forty-site retrospective study of 947 patients undergoing tuberculum sellae meningiomas resection. Standard statistical methods and propensity matching were used. The M-M scale predicted visual worsening (odds ratio [OR]/point: 1.22, 95% CI: 1.02-1.46, P = .0271) and gross total resection (GTR) (OR/point: 0.71, 95% CI: 0.62-0.81, P < .0001), but not recurrence ( P = .4695). The scale was simplified and validated in an independent cohort for predicting visual worsening (OR/point: 2.34, 95% CI: 1.33-4.14, P = .0032) and GTR (OR/point: 0.73, 95% CI: 0.57-0.93, P = .0127), but not recurrence ( P = .2572). In propensity-matched samples, there was no difference in visual worsening ( P = .8757) or recurrence ( P = .5678) between TCA and EEA, but GTR was more likely with TCA (OR: 1.49, 95% CI: 1.02-2.18, P = .0409). Matched patients with preoperative visual deficits who had an EEA were more likely to have visual improvement than those undergoing TCA (72.9% vs 58.4%, P = .0010) with equal rates of visual worsening (EEA 8.0% vs TCA 8.6%, P = .8018). The refined M-M scale predicts visual worsening and EOR preoperatively. Preoperative visual deficits are more likely to improve after EEA; however, individual tumor features must be considered during nuanced approach selection by experienced neurosurgeons.

Anatomical step-by-step dissection of common approaches to the third ventricle for trainees: surgical anatomy of the anterior transcortical and interhemispheric transcallosal approaches, surgical principles, and illustrative pediatric cases.

To create a high-quality, cadaver-based, operatively oriented resource documenting the anterior transcortical and interhemispheric transcallosal approaches as corridors to the third ventricle targeted towards neurosurgical trainees at all levels. Two formalin-fixed, latex-injected specimens were dissected under microscopic magnification and endoscopic-assisted visualization. Dissections of the transcortical and transcallosal craniotomies with transforaminal, transchoroidal, and interforniceal transventricular approaches were performed. The dissections were documented in a stepwise fashion using three-dimensional photographic image acquisition techniques and supplemented with representative cases to highlight pertinent surgical principles. The anterior transcortical and interhemispheric corridors afford excellent access to the anterior two-thirds of the third ventricle with varying risks associated with frontal lobe versus corpus callosum disruption, respectively. The transcortical approach offers a more direct, oblique view of the ipsilateral lateral ventricle, whereas the transcallosal approach readily establishes biventricular access through a paramedian corridor. Once inside the lateral ventricle, intraventricular angled endoscopy further enhances access to the extreme poles of the third ventricle from either open transcranial approach. Subsequent selection of either the transforaminal, transchoroidal, or interforniceal routes can be performed through either craniotomy and is ultimately dependent on individual deep venous anatomy, the epicenter of ventricular pathology, and the concomitant presence of hydrocephalus or embryologic cava. Key steps described include positioning and skin incision; scalp dissection; craniotomy flap elevation; durotomy; transcortical versus interhemispheric dissection with callosotomy; the aforementioned transventricular routes; and their relevant intraventricular landmarks. Approaches to the ventricular system for maximal safe resection of pediatric brain tumors are challenging to master yet represent foundational cranial surgical techniques. We present a comprehensive operatively oriented guide for neurosurgery residents that combines stepwise open and endoscopic cadaveric dissections with representative case studies to optimize familiarity with third ventricle approaches, mastery of relevant microsurgical anatomy, and preparation for operating room participation.

Comparison of transcranial brain stimulation approaches: prefrontal theta alternating current stimulation enhances working memory performance.

One of the most important cognitive functions in our everyday life is the working memory (WM). In several neuropsychiatric diseases such as ADHD or schizophrenia WM deficits can be observed, making it an attractive target for non-invasive brain stimulation methods like transcranial electrical stimulation (tES). However, the literature shows rather heterogeneous results of tES effects on WM performance. fMRI meta-analyses have identified a WM network including frontoparietal brain areas such as the dorsolateral prefrontal cortex (DLPFC) and the posterior parietal cortex (PPC). Neurophysiological studies revealed oscillatory activity in the theta band frequency range to be of crucial functional relevance for WM processes. Based on this, transcranial alternating current stimulation (tACS) in the theta frequency range targeting DLPFC and PPC in a spatially optimized way might further improve effects of tES on WM performance. Sixteen healthy subjects were stimulated with varying stimulation settings on four different days in a counterbalanced within-subject design. These setups included the application of (1) tACS with a frequency of 5 Hz (theta frequency range) over the left DLPFC and (2) the right superior parietal cortex, (3) transcranial direct current stimulation (tDCS) of the DLPFC and (4) a sham stimulation condition during the online performance of a visual delayed-match-to-sample task with varying working memory load. We introduce a procedure to calculate an optimal tES model revealing optimized high-density setups for the present study for 3 cathodes and 1 anode and stimulation currents of 1.5 mA. A significant interaction effect of stimulation type and load condition on working memory capacity was found. This was reflected by a significant improvement of WM performance in the high load condition during tACS over the left DLPFC compared with sham stimulation, which was not the case for our parietal tACS or tDCS setup. Working memory performance can be improved with optimized high-definition tACS with a frequency of 5 Hz over the left DLPFC. The conception of different mechanisms underlying transcranial electrical stimulation with alternating and direct currents is supported by these results. Patients suffering from working memory impairments due to neuropsychiatric diseases might potentially benefit from this brain stimulation approach.

Craniofacial malignant tumors, their extensions, and surgical strategy for their treatment

Purpose: To identify extension routes of craniofacial malignancies and formulate a surgical treatment plan based thereupon. Material and Methods: We retrospectively reviewed the medical records of 253 patients with craniofacial malignancies who underwent surgical treatment at the Romodanov Neurosurgery Institute from 2002 through 2022. Of the 253 patients, 112 had a primary tumor, and 141, a secondary tumor. Preoperative Karnofsky performance scores ranged from 50 to 70 points. Patients underwent neurological and ophthalmological status assessment, as per routine protocols. Results: Epithelial malignancies were the most common (53.7%), whereas anaplastic meningioma and embryonal malignancies were rather uncommon (1.2% and 0.4%, respectively) craniofacial malignancies. The presence of certain clinical symptoms was associated primarily with tumor origin and extension. A high rate of general brain and rhinological symptoms in our study sample was caused by a high percentage of intracranial and paranasal sinus tumors. Craniofacial malignancies most commonly originate from the midline (particularly, anterior midline skull base). Ethmoidal labyrinth was the most common site of origin (45.0%), followed by a sphenoid sinus (12.2%), pterygopalatine and infratemporal fossae (9.9%), whereas the cavernous sinus and olfactory fossa were the least common sites of origin (0.4% and 1.2%, respectively). Craniofacial tumors extended most commonly intracranially (transdurally, epidurally, via adhesion to the dura mater, and/or cavernous sinus growth) or intraorbitally. Anterior craniofacial resection (bifrontal craniotomy with combined with either lateral rhinotomy or supraorbital advancement; or a subcranial approach) was the most common surgical treatment. Postoperative cerebrospinal fluid rhinorrhea and infectious complications (meningitis and meningoencephalitis) were the most frequent complications. The overall postoperative mortality rate was 2.0%. Conclusion: First, compared to the transcranial and facial approaches, the craniofacial resection is advantageous in terms of the radicality of tumor excision. Second, the subcranial approach is preferable to the bifrontal approach in the presence of marked extracranial tumor component, whereas the transbasal Derome approach is effective in the presence of marked extracranial and/or intracranial tumor components. Finally, both the orbitozygomatic and infratemporal approaches allow for the radicality of excision of lateral skull base malignancies, but the latter approach is associated with a lower rate of complications.