Purely Endoscopic Subtemporal Keyhole Approach for Trigeminal Schwannomas: Surgical Techniques and Early Results.

Background And Objectives: In the past, microscopic transcranial approach was the mainstay of treatment of trigeminal schwannomas. In recent years, several endoscopic procedures have been reported for trigeminal schwannomas. For trigeminal schwannomas arising around the Meckel cave, we introduced a fully endoscopic procedure with a small temporal craniotomy in June 2020 and have performed radical tumor removal as in the conventional approach.

[Surgical Approaches for Cerebellopontine Angle/Petroclival Meningiomas].

Considering that most meningiomas are pathologically benign, tumors located in the cerebellopontine angle and petroclival area should be reduced as much as possible, and radiation therapy should be administered if necessary. Consequently, relatively good preservation of cranial nerve function and local lesion control can be expected. However, because the lesions are generally located deep, and are surrounded by various important structures, performing surgical procedures is difficult, and careful management of the surgical strategy is important to avoid complications.

Purely endoscopic subtemporal keyhole anterior transpetrosal approach to access the petrous apex region: surgical techniques and early results.

Objective: The anterior transpetrosal approach using a microscope to provide wider access to the petrous apex region has been described for radical resection of lesions of the middle and posterior skull base. The microscopic anterior transpetrosal approach (mATPA) requires a wide craniotomy and meticulous epidural procedures to minimize temporal lobe retraction. Recently, the clinical application of transcranial endoscopic keyhole approaches for minimally invasive surgery has been steadily expanding.

Usefulness of Opening the Diaphragma Sellae Before Transecting Interclinoidal Ligament for Endoscopic Endonasal Transoculomotor Triangle Approach: Technical Nuances and Surgical Outcomes.

Objective: Opening the oculomotor triangle (OT) and removing the posterior fossa lesion by endoscopic endonasal approach (EEA) is challenging for even an experienced endoscopic neurosurgeon. We summarize the treatment experience and technical nuances with EEA for resection of pituitary neuroendocrine tumors and cavernous sinus (CS) meningiomas invading through the OT.

Methods: Between 2018 and 2022, 8 patients, comprising 5 with pituitary neuroendocrine tumors (3 with nonfunctioning and 2 with somatotroph tumors with increased levels of growth hormone) and 3 CS meningiomas, were treated using an endoscopic endonasal transoculomotor triangle approach.

Angiographic Evaluation of the Feeding Artery in Skull Base Meningioma.

To identify the characteristics of feeding arteries in skull base meningioma including location and prevalence, we evaluated the distributions and types of feeding arteries in skull base meningioma by cerebral angiography and assessed relationships to tumor attachment. We enrolled patients with skull base meningioma who underwent MRI and cerebral digital subtraction angiography (DSA), from September 2015 to October 2022. Subjects comprised 115 patients (32 males, 83 females; mean age, 52.

Surgical Strategy in Modification of the Transpetrosal Approach to Avoid Postoperative Venous Complications: A Report of 74 Consecutive Cases.

Background: The transpetrosal approach is a complex skull base procedure with a high risk of complications, particularly caused by injury of the venous system. It is in part related to variability of blood outflow pathways and their distinctive patterns in each individual patient.

Objective: To evaluate outcomes and complications after skull base surgery with use of the petrosal approach modifications, which selection was based on the detailed preoperative assessment of venous drainage patterns.

Endoscopic endonasal approach to remove pediatric intraventricular tumors of the third ventricle.

Purpose: Pediatric intraventricular tumors of the third ventricle are among the most difficult-to-treat brain tumors. Recently, endonasal endoscopic surgery for suprasellar, third ventricle, and median clivus lesions has become the common procedure, and its indications are expanding to pediatric cases. We describe our strategy for endonasal endoscopic surgery for pediatric third ventricle tumors.

Endoscopic Supraorbital Eyebrow Approach for Medium-Sized Tuberculum Sellae Meningiomas: A Cadaveric Stepwise Dissection, Technical Nuances, and Surgical Outcomes.

Background: Tuberculum sellae meningiomas (TSMs) have traditionally been removed using a transcranial approach. In recent years, endoscopic surgery for TSMs has been reported with an expansion of indications.

Objective: We have performed a fully endoscopic supraorbital keyhole approach for small to medium-sized TSMs and performed radical tumor removal similar to conventional transcranial procedure.

[Endoscopic Endonasal Surgery for Pediatric Suprasellar Tumors].

Pediatric suprasellar tumors are difficult to treat. Their sellar-suprasellar location frequently results in compression of the adjacent critical neurovascular structures, making them a challenging surgical entity. Our surgical strategy emphasizes on radical resection of the tumor without compromising visual or cognitive functions.

Endoscopic Endonasal Transpterygoid Approach for Resection of Carotid Sympathetic Plexus Schwannomas: A Cadaveric Stepwise Dissection, Technical Nuances and Surgical Outcomes.

Objective: Carotid sympathetic plexus (CSP) schwannomas are rare brain tumors located in a complex site around the cavernous sinus and carotid canal in the petrous bone. This study describes 3 cases of CSP schwannomas that underwent surgical removal of the tumor through an endoscopic endonasal transpterygoid approach.

Methods: Between 2016 and 2021, 3 cases of CSP schwannomas were treated using an endoscopic endonasal transpterygoid approach.

Visualization of Resected Area in Endonasal Endoscopic Approach versus Transcranial Approach for Skull Base Meningiomas by Voxel-Based-Lesion Mapping.

Background: We aimed to evaluate the resected area of endonasal endoscopic approach (EEA) and transcranial approach (TCA) for skull base meningiomas (SBMs) using voxel-based-lesion mapping and visualized the appropriate tumor location in each approach.

Methods: We retrospectively examined 182 patients with SBMs who underwent tumor resection in our hospital between 2014 and 2019. Pre- and post-operative SBMs were manually delineated on MRI to create the voxels-of-interest (VOI and VOI) and were registered onto the normalized brain (normalized VOI and normalized VOI).

Endoscopic Contralateral Interhemispheric Transfalcine Keyhole Approach for Large Falcine Meningiomas.

Objective: Falcine meningioma is usually approached ipsilaterally, and the technique for tumor removal has traditionally been performed under microscopy. We report a surgical procedure for large falcine meningioma by an endoscopic contralateral interhemispheric transfalcine keyhole approach.

Methods: The study period was from September 2019 to March 2021.

[How to Use a High-Speed Drill and an Ultrasonic Aspirator During Skull Base Surgery].

During surgery for skull base lesions, maximum efforts should be made to improve the removal rate of the lesion while avoiding complications, and it is necessary to expand the surgical field by selecting appropriate surgical instruments and equipment. In both microsurgery and endoscopic surgery, high-speed drills and ultrasonic aspirators contribute significantly to the safe and reliable removal of skull base lesions, and the surgeons need to be familiar with these characteristics. The specific vital points are as follows: (1) Preparation of the appropriate environment for using a high-speed drill or an ultrasonic aspirator with the understanding of the microsurgical anatomy, (2) Bone excision using a high-speed drill with the selection of an appropriate drill attachment or drill bar tip according to the site of use, (3) Internal decompression of lesions using an ultrasonic aspirator with appropriate settings, (4) Additional expansion of the surgical field by using an ultrasonic aspirator in the osteotomy mode, and so on.

Capillary hemangioma of the sphenoid sinus with intrasellar and parasellar extensions.

Capillary hemangiomas are benign vascular tumors usually diagnosed in infancy and involving skin and soft tissues. We report a rare case of an adult capillary hemangioma of the left sphenoid sinus extending into the intrasellar and parasellar regions. A 71-year-old woman presented with complaints of headaches and diplopia.

Osaka Sliding Knot Seals Dural Defect Simply in Extended Endoscopic Endonasal Approach.

An extended endoscopic endonasal approach (EEA) has become standard for parasellar and midline skull base lesions. However, postoperative leakage of cerebrospinal fluid (CSF) can result from dural defects after lesion removal. We present a simple and effective technique, the Osaka sliding knot, to prevent CSF leakage.

Ectopic thyroid tissue at the skull base: a case report.

Ectopic thyroid tissue is a rare entity, resulting from developmental abnormality during the migration of the embryonic thyroid germ from the floor of the primitive foregut to its final pre-tracheal position. Although ectopic thyroid tissue may be located anywhere, its location at the skull base is extremely rare. We report a case of ectopic thyroid tissue at the skull base in a 19-year-old man with multimodality imaging findings.

Pediatric giant cell reparative granuloma of the lower clivus: A case report and review of the literature.

Giant cell reparative granuloma (GCRG) is a benign nonneoplastic granulomatous lesion and is rare in the cranial bone. We present a pediatric case of this lesion arising from the condyle and lower clivus. A 9-year-old girl presented with slowly progressive hoarseness and dysphagia.

Minimal anterior and posterior combined transpetrosal approach for large petroclival meningiomas.

Objective: Petroclival meningiomas (PCMs) remain difficult to remove, and radical tumor resection continues to pose a relatively high risk of neurological morbidity in patients with these lesions because of the proximity of the tumor to neurovascular structures. The anterior and posterior combined (APC) transpetrosal approach allows resection of a large petroclival lesion with minimal retraction of the temporal lobe. However, this approach is thought to be complex and time-consuming.

Changes in cognitive function after resection of lesions in the anterior part of the lateral ventricle via an interhemispheric transcallosal approach.

Anterior callosotomy to about 20 mm has been considered relatively safe empirically. The present study aimed to compare cognitive function before and after resection of tumors in the anterior part of the lateral ventricle. We analyzed 6 patients with intraventricular tumors located in the anterior horn or body of the lateral ventricle who underwent surgical excision via interhemispheric transcallosal approach at Osaka City University Hospital between March 2015 and August 2018.

Usefulness of the anterior transpetrosal approach for pontine cavernous malformations.

Surgical resection of pontine cavernous malformation remains a particularly formidable challenge. We report the surgical outcome of eight cases with pontine cavernous malformations operated using the anterior transpetrosal approach. All cases presented with neurological deficits caused by hemorrhage before surgery.

Surgical implementation and efficacy of endoscopic endonasal extradural posterior clinoidectomy.

Objective: The endoscopic endonasal approach (EEA) for skull base tumors has become an important topic in recent years, but its use, merits, and demerits are still being debated. Herein, the authors describe the nuances and efficacy of the endoscopic endonasal extradural posterior clinoidectomy for maximal tumor exposure.

Methods: The surgical technique included extradural posterior clinoidectomy following lateral retraction of the paraclival internal carotid artery and extradural pituitary transposition.