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. In this study, the details of the purely endoscopic subtemporal keyhole ATPA (eATPA) for petrous apex lesions are described and its initial results are reported. METHODS: Between May 2022 and May 2023, the authors performed eATPA in 10 patients with petrous apex lesions, of which 6 were meningiomas, 3 were trigeminal schwannomas, and 1 was epidermoid cyst. The surgical procedure of the purely eATPA is as follows. After a small temporal craniotomy, the endoscopic procedure is started. The anterior rim of the petrous bone and Meckel's cave are exposed via an intradural subtemporal approach. The lesion is removed with additional drilling of Kawase's triangle, cutting the superior petrosal sinus, opening Meckel's cave, and cutting the tentorium. The authors also compared the outcomes of mATPA versus eATPA for consecutive cases of petrous apex lesions. RESULTS: Gross-total resection was achieved in 8 of the 10 patients. The average operative time was 4 hours 13 minutes. There were 3 cases of transient abducens nerve palsy and 1 case of trochlear nerve palsy in the postoperative period. No new-onset motor deficits or CSF leakage was noted in any of these patients. Only 1 patient exhibited postoperative asymptomatic temporal lobe edema. The Karnofsky Performance Scale (KPS) scores remained unchanged or improved for all patients postoperatively. Compared with mATPA, eATPA achieved a similar extent of resection and comparable postoperative KPS scores with a significantly shorter mean operative time, much smaller temporal craniotomy, and thus less mean blood loss during surgery with lower rates of new-onset temporal lobe edema in the postoperative period. CONCLUSIONS: An eATPA allows a direct route to access Meckel's cave and posterior cranial fossa lesions similar to conventional mATPA, with shortening the operative time and reducing the risk of postoperative temporal lobe edema. This eATPA is considered one of the new surgical techniques that can be expected to develop in the future.

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. The critical surgical technique is continuously opening the diaphragma sellae from medial to lateral toward the interclinoidal ligament and transecting it to enlarge the OT. We evaluated preoperative tumor size, previous surgical history, preoperative symptoms, extent of tumor resection, histopathology, and postoperative complications for all patients. RESULTS: The gross total resection (defined as complete removal) in 3 patients (38%), near-total resection (defined as >95% removal) in 4 patients (50%), and subtotal resection (defined as ≤90% removal) in 1 patient (12%) and gross total resection of tumor invading through the OT was achieved in all patients through pure EEA. Two of 3 patients with visual deficits in nonfunctioning pituitary neuroendocrine tumors improved, and the other remained stable postoperatively. One patient showed transient oculomotor nerve palsy. The growth hormone level of the 2 patients with somatotroph tumors declined to normal. For 3 patients with CS meningiomas, cranial nerve palsy improved in 2 patients, whereas the other patient developed increased facial numbness after surgery. CONCLUSIONS: The endoscopic endonasal transoculomotor triangle approach is an efficient surgical option for tumors with CS invasion and OT penetration.

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. METHOD: We report on surgical anatomies and our surgical procedures in detail, including case presentations. RESULT: Endoscopic endonasal surgery has the advantage of providing a wider view of the tumor site, hypothalamus, optic chiasm, and other critical structures. Good indications for the endoscopic endonasal approach for intra-third ventricular tumors are those arising from the floor of the third ventricle. In particular, craniopharyngioma, a typical pediatric suprasellar tumor, sometimes extends into the third ventricle, causing great operative difficulty. However, aggressive removal for long-term control while preserving memory and visual function is important. We perform surgery with a strategy of radically removing tumors without causing damage to visual or brain function, and we adopt the "4-hands technique by two neurosurgeons" in full endoscopic surgery to remove tumors safely and aggressively. CONCLUSION: We describe our strategy for endonasal endoscopic surgery for pediatric third ventricle tumors, especially those extending from the suprasellar region into the third ventricle, and present a representative case.

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. We report the details of this surgical procedure including cadaveric stepwise dissection and initial surgical results for small to medium-sized TSMs. METHODS: We used an endoscopic supraorbital eyebrow approach for 6 patients with TSMs between September 2020 and September 2022. Mean tumor diameter was 16.0 mm (range, 10-20 mm). The surgical approach included an eyebrow skin incision ipsilateral to the lesion, a small frontal craniotomy, subfrontal exposure of the lesion, removal of the tuberculum sellae, unroofing of the optic canal, and resection of the tumor. The extent of resection, preoperative and postoperative visual function, complications, and operative time were evaluated. RESULTS: Optic canal involvement was observed in all patients. Two patients (33%) showed visual dysfunction before surgery. Simpson grade 1 tumor resection was achieved in all cases. Visual function was improved in 2 cases, and remained unchanged in 4 cases. Postoperative pituitary function was preserved in all cases, with no decreases in olfaction. CONCLUSIONS: The endoscopic supraorbital eyebrow approach for TSMs allowed resection of the lesion, including tumor extending to the optic canal, with a good surgical view. This technique is minimally invasive for patients and may represent a good surgical option for medium-sized TSMs.

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. Preoperative tumor size, preoperative and postoperative symptoms, internal carotid artery (ICA) displacement, extent of tumor resection, intraoperative findings showing tumor origin, and surgical complications were evaluated in all patients. RESULTS: Two tumors were in the petrous region, and the other one was in both the petrous and cavernous regions. The median tumor diameter was 41.3 mm. In the 3 cases, the ICA was displaced to the superolateral side, the anterolateral side, and the posterior side, respectively. Near-total resection was achieved in all 3 cases via an endoscopic endonasal transpterygoid approach. There were no endonasal postoperative complications, and the cranial nerve disability improved in all 3 patients at 1-year follow-up. CONCLUSIONS: The surgical technique for CPS schwannoma using an endoscopic endonasal transpterygoid approach may be a viable option because endoscopy has been proven to offer better intraoperative visualization and reduce postoperative discomfort for patients. Tumors located medial and inferior to the ICA pars cavernous sinus or anterior, inferior, and medial to the paraclival ICA are ideal candidates for surgery using this endoscopic approach.

Clinical Features of Ruptured Very Small Intracranial Aneurysms (<3 mm) in Patients with Subarachnoid Hemorrhage.

OBJECTIVE: Although small unruptured aneurysms rarely rupture, many patients with subarachnoid hemorrhage (SAH) have ruptured small, especially very small intracranial aneurysms (VSIAs; <3 mm) in clinical practice. We aimed to clarify the proportion and clinical features of patients with SAH with ruptured VSIAs. METHODS: 609 patients with ruptured intracranial aneurysms diagnosed at our institution from January 2012 to December 2018 were retrospectively analyzed. We classified patients into 2 groups based on ruptured aneurysm size: VSIAs or non-VSIAs (≥3 mm). We analyzed age, sex, location of aneurysms, World Federation of Neurological Surgeons grade on admission, treatment modality, and outcome at discharge. RESULTS: Among 609 patients, 103 had ruptured VSIAs. The proportion of young patients (age <40 years) was greater in the VSIA group than the non-VSIA group (10.7% vs. 3.6%, P = 0.002). The proportions of VSIAs located in the middle cerebral and vertebrobasilar arteries were relatively low and high, respectively (P = 0.002, 0.005). Significantly more patients with VSIAs than those with non-VSIAs were classified under World Federation of Neurological Surgeons grade I-III (70.9% vs. 56.3%, P = 0.006). Coil embolization was preferred for VSIAs (68.0% vs. 32.0%, P = 0.006). Outcomes were more favorable in the VSIA group than in the non-VSIA group. CONCLUSIONS: Small unruptured aneurysms rarely rupture; however, many patients with SAH have ruptured VSIAs in clinical practice. We observed that VSIA rates among ruptured aneurysms were fairly high. Age, posterior circulation location, and preferable outcome may be important clinical characteristics of ruptured VSIAs.

Current treatment options and prognostic factors for ruptured distal anterior cerebral artery aneurysms.

BACKGROUND: Distal anterior cerebral artery (ACA) aneurysms are rare, representing 1-9% of all intracranial aneurysms. The best treatment strategy for these aneurysms continues to be debated. We clarified the clinical features and treatment outcomes of patients with ruptured distal ACA aneurysms according to the treatment options at our institute. METHODS: Thirty-seven consecutive patients (26 women; mean age, 65.2 years) with ruptured distal ACA aneurysms who underwent surgical clipping or coil embolization between 2012 and 2018 were included in the study. Clinical presentations, radiographic findings, and outcomes were retrospectively reviewed and compared between patients who underwent either surgical clipping or coil embolization. Risk factors associated with poor outcomes (modified Rankin Scale 4-6) were analyzed using multiple regression analysis. RESULTS: Nineteen patients (51.4%) had World Federation Neurological Surgeons (WFNS) Grade IV-V, 18 (48.7%) had frontal lobe hematomas, and 13 (35.1%) had multiple aneurysms. Surgical clipping and endovascular coiling were performed in 28 (75.7%) and nine (24.3%) patients, respectively. Aneurysms located at the A4-5 portions were mainly treated by surgical clipping (P = 0.04). There were no significant between-group differences in procedure-related morbidity and mortality; however, the complete occlusion rate was higher in the surgical group (P < 0.01). Overall, a favorable neurological outcome at discharge (mRS 0-3) was obtained in 23 patients (62.5%). Multiple regression analysis revealed that WFNS Grade IV-V and frontal lobe hematomas were risk factors for poor outcomes (mRS 4-6). CONCLUSION: Acceptable outcomes were obtained in 62.5% of cases, and there were no significant between-group differences in treatment results between clipping and coiling. A poor WFNS grade and intracerebral hematomas were risk factors for a poor prognosis.

[Surgical Management of a Thromobotic Extracranial Carotid Artery Aneurysm:A Case Report].

Extracranial carotid artery aneurysms are relatively rare. We present a case involving a giant aneurysm arising from the extracranial carotid artery. The patient was a 79-year-old woman. She had a pulsating mass in the right side of her neck. However, she was neurologically intact. Contrast-enhanced CT scans of the neck showed an enhanced mass lesion with a thrombus in the right side of her neck. Angiography revealed a saccular aneurysm 3.4 cm in size near the bifurcation site of the right common carotid artery into the external carotid artery. She underwent an urgent resection of the aneurysm and a carotid artery reconstruction. Postoperatively, she recovered well and the total resection of the lesion was angiographically confirmed. Histopathological examination revealed that the wall of the aneurysm had undergone fibrosis and contained a few elastic fibers and microhemorrhages. The wall of the aneurysm was also infiltrated by inflammatory cells. The surgical strategy for and appropriate preoperative evaluation of this rare disease was discussed.

Atypical postoperative radiographical findings in a patient with moyamoya disease: A case report.

Moyamoya disease is a chronic cerebrovascular disease characterized by spontaneous and progressive stenosis or occlusion of the internal carotid artery and its branches. Revascularization procedures have been shown to improve cerebral hemodynamics and decrease the risk of strokes, but several postoperative complications are known to occur.A 14-year-old girl with moyamoya disease with a history of left-sided revascularization surgery underwent right-sided revascularization. On postoperative day 4, she experienced a transient neurological event (left hemiparesis). Magnetic resonance imaging revealed large cortical and subcortical hyperintense lesions in the middle cerebral artery territory on diffusion-weighted imaging and apparent diffusion coefficient imaging. Subsequently, the radiographic findings improved within several days with resolution of the symptoms. This case is a reminder that hemodynamic complications can develop subacutely in patients who have undergone successful revascularization for moyamoya disease. The radiological features and mechanisms of this rare condition associated with revascularization surgery for moyamoya disease are discussed.