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Background: Anterior communicating artery (ACOM) aneurysms are among the most common aneurysms associated with aneurysmal subarachnoid hemorrhage (International Study of Unruptured Intracranial Aneurysms I (N Engl J Med 339:1725-1733, 1998), Wiebers (Lancet 362:103-110, 2003)). Surgical clipping of posterior-superiorly projecting ACOM aneurysms can be challenging, as the ipsilateral A2 can interfere with clip trajectory and ACOM perforating vessels obstructed from view. Intraluminal coils can further increase the difficulty of the procedure. Method: The relevant surgical anatomy with illustration is presented. A video detailing our technique on an illustrative case is provided. Conclusion: Surgical clipping of posterior-superiorly projecting ACOM aneurysms can require complex clip configurations. We describe the key steps of posterior-superiorly projecting ACOM aneurysm clipping through a lateral supraorbital craniotomy and fenestrated tandem clipping. [ABSTRACT FROM AUTHOR]

Background: Tentorial dural arteriovenous fistulas (dAVFs) are categorized based on venous drainage and location. Although their angioarchitecture may initially appear intimidating, once "decodified," treatment is straightforward. Posteromedial tentorial dAVFs have an arterialized draining vein that emanates from the inferior tentorium along the posterior third of the straight sinus, just slightly off the midline. Method: With the aid of anatomical dissections, intraoperative photos, and operative videos, we outline the key steps for surgical treatment of posteromedial tentorial dAVFs. Conclusion: Posteromedial tentorial dAVFs constitute a precise and well-defined subtype of tentorial dAVF for which surgical ligation has an important role. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to scientifically review to determine the incidence, prevention protocols and recovery rate and reach a desirable protocol for the management of inferior alveolar nerve (IAN) injury and lingual nerve (LN) injury using the comprehensive overview of literature during various maxillofacial surgical procedures. Materials and Methods: Literature was selected through a search of PubMed, Cochrane Library and Google Scholar electronic databases. Articles from January 2010 to March 2023 were searched. All language articles with a minimum of 6-month patient follow-up and injury analysis by a patient’s reporting, radiographic and neurosensory testing were selected. Results: In total, 52 literature sources were reviewed, and 21 of the most relevant articles that are suitable to the criteria were selected. The impact of lower third molar removal (especially impacted) on the LN injury and IAN injury was clearly seen. Conclusions: Based on the study, it was clear that most injuries were occurring during removal of mandibular third molar. Thus, cone-beam computed tomography-based pre-operative analysis is a must in such cases. The results were significantly better in the early treatment group compared to the late group. Direct nerve repair without tension gives the best surgical outcome than other methods. Autogenous nerve graft was superior amongst other grafts which were used. Further studies were required to open a new paradigm for nerve repairs.

The International Subarachnoid Aneurysm Trial led to a shift from clipping to endovascular coiling as the primary therapy for cerebral aneurysm particularly in the management of posterior circulation aneurysm. However, endovascular therapy is often unavailable in low-resource settings, emphasizing the importance of maintaining surgical skill sets in resource-poor countries. This article presents a detailed case report on the successful microneurosurgical management of a 65-year-old female with a history of headache and weakness with past history of hypertension and a right posterior cerebral artery territory infarct who was diagnosed with a ruptured aneurysm situated within the intracranial vertebral artery. Patient was operated with the far lateral approach and clipping of the aneurysm. This case report elucidates the intricate surgical techniques employed, and the challenges neurosurgeons encountered in treating posterior circulation intracranial aneurysms, particularly those with ruptured complications. The aneurysms' intricate anatomy and increased rupture risk necessitate a meticulous microneurosurgical approach. The severity of subarachnoid hemorrhage from ruptured aneurysms increases morbidity and mortality rates. [ABSTRACT FROM AUTHOR]

Intracranial epidermoid cysts are rare, benign tumors. Nevertheless, the microsurgical removal of these cysts is challenging. This is due to their capacity to adhere to the neurovascular tissue, as well as the associated difficulties in microsurgically peeling off their capsular wall hidden in dead angles. To better understand the rate of recurrence after surgical intervention, we have performed preoperative and postoperative volumetric analysis of epidermoid cysts, allowing the estimation of their growth rate after resection. Imaging data from 22 patients diagnosed and surgically treated for an intracranial epidermoid cyst between 2000 and 2022 were retrospectively collected from 2 European neurosurgical centers with microsurgical expertise. Volumetric analysis was performed on magnetic resonance imaging data. Average cyst volume at diagnosis, before any surgery, measured in 12 patients was 28,877.6 ± 10,250.4 mm3 (standard error of the mean [SEM]). Estimated growth rate of incompletely resected epidermoids after surgery was 1,630.05 mm3 ± 729.95 (SEM). Assuming linear growth dynamics and normalizing to postoperative residual volume, the average postoperative growth rate corresponded to 61.5% ± 34.3% (SEM) of the postoperative residual volume per year. We observed signs of recurrence during a radiologic follow-up period of 6.0 ± 2.8 years (standard deviation) in more than 50% of our patients. Due to their slow-growing nature, epidermoid cysts can often reach a complex multicompartmental size before resection, even in young patients, thus requiring complex approaches with challenging capsular resection, which implies a high risk of nerve and vascular injury per se. Tumor recurrence may be predicted on the basis of postoperative volumetry. [ABSTRACT FROM AUTHOR]

Objective To evaluate the changes in surgical approaches and treatment strategies for foramen magnum (FM) meningiomas located in the anterior or anterolateral aspect of the medulla oblongata. Methods The clinical data of 72 patients suffering a meningioma attached to dura of the anterior or anterolateral FM rim admitted to General Hospital of the People's Liberation Army from January 2007 to January 2022 were analyzed retrospectively. The relevant literature were reviewed. Results Tumor removal was accomplished via a posterolateral suboccipital retrocondylar approach in all patients. Total resection was achieved in 65 patients (90%). 7 patients (10%) of subtotal resection underwent cyberknife radiosurgery. 12 cases (17%) had hypoglossal nerve dysfunction, and 8 improved within 3 months after surgery. 18 cases (25%) experienced hoarseness and/or difficulty swallowing, 15 improved within 3 months after surgery, and 1 underwent tracheotomy due to posterior cranial nerve paralysis. 1 suffered from hemiplegia due to anterior spinal artery injury. There were no surgical deaths. No tumor recurrence was observed after a mean follow-up period of 3 years (range, 12-60 months) with clinical and MRI examination. Conclusions Microsurgery via retrocondylar approach to remove anterior and anterolateral FM meningiomas can not only meet the needs of surgical exposure, but also avoid excessive bone grinding, achieving good total resection rate, low complications, and long-term satisfactory therapeutic effect. The occurrence of serious complications such as postoperative hemiplegia is mainly due to intraoperative vascular damage. [ABSTRACT FROM AUTHOR]

Objective: We designed a novel intraoperative malleable adjustable continuous suction tube to obtain clear surgical fields, reduce intracranial pressure, and lower the temperature of the surgical area. Methods: This device consists of six parts: continuous suction tube head and cotton patty, suction tube, fixed wire position, fixed clip, spiral plastic pressure regulating valve, and tail. It can continuously extract blood, cerebrospinal fluid, and rinsing solution from surgical fields, with minimal contact and trauma to tissues, nerves, and blood vessels, while also having a negligible impact on the surgeon's focus and procedure. Result: The excellent and safe performance (simple, malleable, adjustable, space-saving, inexpensive, safe, and effective) of this device in clearing the operating field has been proven in more than 2000 neurosurgical operative procedures. We encountered no complications associated with this device, such as cerebral hematoma, postoperative low intracranial pressure, or vascular and nerve injuries. Conclusion: The newly innovated intraoperative malleable adjustable continuous suction tube is effective and safe for microneurosurgery. [ABSTRACT FROM AUTHOR]

Abstract Background Extraction of the mandibular third molar, the most frequent and important surgical procedure in the clinical practice of oral surgery, is associated with the risk of injury of the lingual nerve. Neuropathy of the lingual nerve poses diagnostic challenges regarding the transient or permanent nature of the injury. No consensus or criteria have been established regarding the diagnosis of lingual nerve neuropathy. We applied both Tinel’s test and clinical neurosensory testing together, which can be easily used at the bedside in the early stages of injury. Therefore, we propose a new method to differentiate between lesions with the ability to heal spontaneously and those that cannot heal without surgery. Results Thirty-three patients (29 women, 4 men; mean age, 35.5 years) were included in this study. For all patients, the median interval between nerve injury and initial examination was 1.6 months and that between nerve injury and the second examination before determining the need for surgical management was 4.5 months. The patients were assigned to either group A or B. The spontaneous healing group (group A, n = 10) revealed a tendency for recovery within 6 months after tooth extraction. In this group, although there were individual differences in the degree of recovery, a remarkable tendency for recovery was observed based on clinical neurosensory testing in all cases. None of the patients were diagnosed with allodynia. In seven cases, the Tinel test result was negative at the first inspection, and in three cases, the result changed to negative at the second inspection. Conversely, in group B(n = 23), no recovery trend was observed with regard to clinical neurosensory testing, and nine patients had allodynia. Further, the Tinel test result was positive for all patients in both examinations. Conclusions Our findings indicate that in case of transient lingual nerve paralysis, clinical neurosensory testing findings deteriorate immediately after tooth extraction and gradually recover, while Tinel’s test shows a negative result. Using Tinel’s test and clinical neurosensory testing together enabled early and easy identification of the severity of the lingual nerve disorder and of lesions that would heal spontaneously without surgical management.

Objective: This retrospective study was performed to evaluate the feasibility and safety of surgically clipping intracranial aneurysms using a transcranial neuroendoscopic approach. Methods: 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. Results: 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%). Conclusions: Neuroendoscopy can provide clear visualization and multi-angle views during aneurysm clipping, which is helpful for ensuring adequate clipping and preventing complications. [ABSTRACT FROM AUTHOR]

Intracranial dermoid cysts are rare dysembryonic tumors of benign nature. These are uncommon in adults. If present, they are usually located in the midline or along the lines of embryonic fusion. The posterior fossa region is an infrequent site. Extradural or interdural locations are even more rare. In this case report, the authors report a laterally located large posterior fossa right cerebellar convexity interdural and extradural dermoid cyst over the sigmoid sinus. It was managed by totally extradural maximum possible safe decompression with microneurosurgical technique. The authors share their experience of addressing this rare pathology at the rarest location with unusual imaging findings. [ABSTRACT FROM AUTHOR]

Background: Extraction of the mandibular third molar, the most frequent and important surgical procedure in the clinical practice of oral surgery, is associated with the risk of injury of the lingual nerve. Neuropathy of the lingual nerve poses diagnostic challenges regarding the transient or permanent nature of the injury. No consensus or criteria have been established regarding the diagnosis of lingual nerve neuropathy. We applied both Tinel's test and clinical neurosensory testing together, which can be easily used at the bedside in the early stages of injury. Therefore, we propose a new method to differentiate between lesions with the ability to heal spontaneously and those that cannot heal without surgery. Results: Thirty-three patients (29 women, 4 men; mean age, 35.5 years) were included in this study. For all patients, the median interval between nerve injury and initial examination was 1.6 months and that between nerve injury and the second examination before determining the need for surgical management was 4.5 months. The patients were assigned to either group A or B. The spontaneous healing group (group A, n = 10) revealed a tendency for recovery within 6 months after tooth extraction. In this group, although there were individual differences in the degree of recovery, a remarkable tendency for recovery was observed based on clinical neurosensory testing in all cases. None of the patients were diagnosed with allodynia. In seven cases, the Tinel test result was negative at the first inspection, and in three cases, the result changed to negative at the second inspection. Conversely, in group B(n = 23), no recovery trend was observed with regard to clinical neurosensory testing, and nine patients had allodynia. Further, the Tinel test result was positive for all patients in both examinations. Conclusions: Our findings indicate that in case of transient lingual nerve paralysis, clinical neurosensory testing findings deteriorate immediately after tooth extraction and gradually recover, while Tinel's test shows a negative result. Using Tinel's test and clinical neurosensory testing together enabled early and easy identification of the severity of the lingual nerve disorder and of lesions that would heal spontaneously without surgical management. [ABSTRACT FROM AUTHOR]

Four therapeutic approaches have been developed for the treatment of arteriovenous malformations (AVMs): microsurgery, radiosurgery, embolization, and conservative treatment. The lack of consensus regarding the choice of treatment method and the different specializations of the doctor who are onvolved to the patient with AVM often determine the wrong treatment strategy. We performed a prospective analysis of the results of AVM of the IV degree according to Spetzler‒Martin scale, 4–5 points on the Buffalo scale complex treatment, based on clinical and tomographic data after the use of partial endovascular embolization and radical microsurgical removal of the AVM node assisted by cell saving technology. According to cerebral angiography 4 months follow-up there is no visible AVM vessels, the malformation was completely resected. Treatment of large and giant AVMs (IV and V degrees according to the Spetzler‒Martin scale) requires tailored surgical treatment approache using endovascular, microsurgical and radiosurgical techniques, but in many cases without achieving a radical result. The use of cell saver technology is necessary to reduce the risks of intraoperative complications associated with blood loss during microsurgical intervention, and enables radical removal of the AVM and recovery of the patient. The role of cell saver technology is crucial in vascular microsurgical interventions, which are often accompanied by a significant volume of blood loss, ensuring rapid autologous hemotransfusion and restoration of circulating blood volume. Endovascular embolization is a necessary step to reduce the risks of intraoperative complications during microsurgical intervention, which, together with the use of cell saver technology, makes it possible to achieve radical AVM removal and patient recovery.

The horizontal fissure of the cerebellum, which is the largest and most prominent fissure, has received less interest from anatomists and neurosurgeons. Hence, the current study aims to provide comprehensive detail about the horizontal fissure and its anatomic and surgical relationship with deeper structures such as the dentate nucleus and middle cerebellar peduncle for the benefit of the neurosurgeon. Ten whole formalin-fixed human cadaveric cerebellar hemispheres were obtained from human cadavers donated to the institution. Different parameters of the horizontal fissure were studied, such as length, depth (medial end, lateral end, and middle), sulcal and gyral variations (superficial and deep), and its close relationship, especially at depth, with the dentate nucleus and middle cerebellar peduncle. The total length of the horizontal fissure on the right and the left side was 64.3 ± 7.9 mm (range, 53–77 mm) and 65.6 ± 8.01 mm (range, 53–79 mm), respectively. The medial third of the horizontal fissure, with the fewest vessels, was the most suitable place to puncture or start the dissection of the horizontal fissure. The surface projection of the center of the posterior border of the dentate nucleus lies within 20–21 mm on either side of the posterior midline along the horizontal fissure and is only approximately 4 mm deep from the horizontal fissure. The anatomic measurements and relationships provided in this description of the horizontal fissure will serve as a tool for surgery selection and planning, as well as an aid to improve microneurosurgical techniques, with the final goal being better patient outcomes. [ABSTRACT FROM AUTHOR]

Modern technologies in neurosurgery are analyzed. Revolutionary transformations related to them in the diagnosis and treatment of pathology of the brain and spinal cord are discussed. Thanks to technology, recognition of lesions of the CNS has become remote, and their treatment is minimally invasive. At the same time, the threats that magnificent methods carry are revealed: atrophy of clinical thinking, hyposkillia, disconnection between the doctor and the patient. Grounded measures preventing the development of dehumanizing medicine and, in particular, neurosurgery. [ABSTRACT FROM AUTHOR]

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Advanced neurosurgical techniques have been assessed. The related revolutionary advances in the diagnosis and treatment of brain and spinal cord disorders have been discussed. Thanks to technology, remote CNS lesion recognition has become available, and treatment of such lesions has become minimally invasive. However, threats coming from the use of excellent methods have been revealed, such as loss of clinical thinking, hyposkillia, and disunity among physicians and patients. The measures to prevent dehumanization in medicine, particularly neurosurgery, have been justified.

Abstract Background No studies have compared the outcomes of direct perineurial suture with vein graft cuff repair and indirect collagen allograft repair of the lingual nerve following an injury. Therefore, we evaluated and compared the outcomes of each over a 1-year observation period. We retrospectively assessed 20 patients who had undergone microneurosurgical repair of unilateral lingual nerve injuries at the Wakayama Medical University Hospital between May 2015 and March 2019. We utilized two different methods for lingual nerve repair, i.e., direct perineurial repair with a vein graft cuff and interpositional collagen allograft repair. Sensory and taste function in the lingual nerve were preoperatively evaluated using a static two-point discrimination test, superficial pain/tactile sensation test, tests for the pressure pain threshold (Semmens-Weinstein monofilament), test for thermal discrimination hot and cold sensation, and a taste discrimination test. These tests were performed again at 6 and 12 months postoperatively. Results Compared to the preoperative conditions, all patients showed improved sensory reactions. Functional sensory recovery outcomes were defined by Pogrel’s criteria, Medical Research Council Scale grades, and functional sensory recovery. In each group, all patients improved after the operation. However, the operation time was significantly shorter for an interpositional collagen allograft repair as compared to that for a direct perineurial repair with a vein graft cuff. Conclusions There were no statistically significant differences between the two repair Methods, except for the operation time. Both methods led to satisfactory results for all criteria. From an economic point of view, direct perineurial repair with a vein graft cuff is meaningful; however, the esthetic effect on the donor site should be considered. Conversely, interpositional collagen allograft repair has the advantage of a greatly shortened operation time.

Objective: This retrospective study was performed to evaluate the feasibility and safety of surgically clipping intracranial aneurysms using a transcranial neuroendoscopic approach. Methods: 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. Results: 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%). Conclusions: Neuroendoscopy can provide clear visualization and multi-angle views during aneurysm clipping, which is helpful for ensuring adequate clipping and preventing complications.

Background: Vestibular schwannomas (VS) are usually hypovascularized benign tumors. Large VS (Koos grade IV) with unusual vascular architecture are defined as hypervascular (HVVS); the excessive bleeding during microsurgery has a negative impact on results. Methods: Forty consecutive patients were operated on for HVVS (group A). A tendency to bleed and adherence of capsule to nervous structures were evaluated by reviewing intraoperative video records. The cisternal facial nerve (FN) position was reported. Microsurgical removal was classified as total, near-total, subtotal, or partial and the MIB-1 index was evaluated in all. FN results were classified according to the House-Brackmann scale. Results: Results of Group A were compared with those of 45 patients operated on for large low-bleeding VS (group B). Mean tumor diameter was 3.81 cm in group A and 3.58 cm in group B; the mean age was 42.4 and 56.3 years, respectively. The mean American Society of Anesthesiologists Physical Status Scale class of group A was 1.67 versus 2.31 of group B (P < 0.01). Total or near-total resection was accomplished in 76.5% of group A versus 73.3% of group B. Tight capsule adhesion was observed in 67.5% of group A versus 57.8% of group B. Mean MIB-1 was 1.25% and 1.08%, respectively.FN anatomic preservation was possible in 84.6% of group A versus 95.5% of group B; 67.5% of group A had HB grade I or II FN outcome versus 93.3% of group B (P < 0.001). In group A, 8 patients (20.0%) experienced transient postoperative complications versus 4.4% of group B. Recurrence/regrowth was observed in 4 patients in group A versus 1 in group B. Conclusions: Intraoperative video for classification of HVVS was used. Microsurgery of large HVVS was associated with higher (usually transient) complications and recurrence/regrowth rates and poorer FN outcome, especially in patients with tight capsule adhesion.

The analysis of modern technologies in neurosurgery was carried out. The revolutionary transformations associated with them in the diagnosis and treatment of the brain and spinal cord diseases are discussed. Thanks to technologies, the CNS lesions have been identified remotely, and their treatment has become minimally invasive. At the same time, the threats posed by these innovative methods have been identified: atrophy of clinical thinking, hyposkillia, separation of the doctor from the patient. The measures preventing the development of dehumanization of medicine and, in particular, neurosurgery are substantiated. [ABSTRACT FROM AUTHOR]

• Our aim was to review the current literature on this topic and define the existing knowledge about the feasibility, safety, and effectiveness of EAM through a meta -analysis. • We discussed the feasibility of endoscope-assisted combined MDU, ICGA and other technologies. • We discussed the feasibility of using EAM for different aneurysms. In the surgical approach to treat deep-seated intracranial lesions, endoscopes can be used to assist microsurgical operations and improve outcomes. This technique is often called endoscope-assisted microneurosurgery (EAM). This systematic review and meta -analysis aimed to evaluate the feasibility, safety, and effectiveness of EAM. We performed a meta -analysis of relevant articles identified using PubMed, Embase, and the Cochrane Central Register to assess the efficacy of EAM according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Primary outcomes were repositioning of the definitive clip, better surgical field, the overall and endoscope-related complication rates, mortality, and the rate of follow up. A total of 10 studies of 1,432 patients with 1,717 aneurysms treated with EAM were included. EAM led to repositioning of the definitive clip in 13% (95% CI, 9%–17%; I 2 = 72.61%; p < 0.001); 77% of aneurysms treated with endoscopically assisted vision and information had a better outcome than that with standard surgery (95% CI, 52%–95%; I 2 = 97.63%; p < 0.001). There was an overall complication rate of 6% (95% CI, 1%–13%; I 2 = 91.39%; p < 0.001). The incidence of endoscope-related complications was 0% (95% CI, 0%–1%; I 2 = 64%; p < 0.001). The mortality was 0% (95% CI, 0–1%; I 2 = 0.0%); and 94% of patients had an excellent to good recovery and good outcome (95% CI, 88%–98%; I 2 = 88.42%; p < 0.001). Our comprehensive study showed that EAM for intracranial aneurysms is feasible, the safety of the surgery is good, and the patients have a good prognosis, Therefore, we think EAM can be more widely adopted in the future. [ABSTRACT FROM AUTHOR]

Less than a quarter of the world population has access to microneurosurgical care within a range of 2 hours. We introduce a simplified exoscope system to achieve magnification, illumination, and video recording in low-resource settings. We combined an industrial microscope tube, a heavy-duty support arm, a wide-field c-mount digital microscope camera, and a light-emitting diode ring light. All parts were sterilized with ethylene oxide. We performed 13 spinal and 3 cranial surgeries with the help of the low-budget exoscope. The average preoperative setup time was 12.8 minutes. The exoscope provided similar magnification and illumination like a conventional binocular microscope. It allowed operating in a comfortable posture. The field of vision ranged from 30 mm–60 mm. The surgical field was captured by a 16-megapixel two-dimensional camera and projected to a 55-inch high-definition television screen in real time. Image quality was similar to that of a conventional microscope although our exoscope lacked stereoscopic view. Adjusting camera position and angle was time-consuming. Thus, the benefit of the exoscope was most notable in spine surgeries where the camera remained static for most of the time. The total cost of the exoscope was approximately U.S. $ 750. Our low-budget exoscope offers similar image quality, magnification, and illumination like a conventional binocular microscope. It may thus help expand access to neurosurgical care worldwide. Users may face difficulty adapting to the lack of depth perception in the beginning. Prospective studies are needed to assess its usability and effectiveness compared to the microscope. [ABSTRACT FROM AUTHOR]

Background: No studies have compared the outcomes of direct perineurial suture with vein graft cuff repair and indirect collagen allograft repair of the lingual nerve following an injury. Therefore, we evaluated and compared the outcomes of each over a 1-year observation period. We retrospectively assessed 20 patients who had undergone microneurosurgical repair of unilateral lingual nerve injuries at the Wakayama Medical University Hospital between May 2015 and March 2019. We utilized two different methods for lingual nerve repair, i.e., direct perineurial repair with a vein graft cuff and interpositional collagen allograft repair. Sensory and taste function in the lingual nerve were preoperatively evaluated using a static two-point discrimination test, superficial pain/tactile sensation test, tests for the pressure pain threshold (Semmens-Weinstein monofilament), test for thermal discrimination hot and cold sensation, and a taste discrimination test. These tests were performed again at 6 and 12 months postoperatively. Results: Compared to the preoperative conditions, all patients showed improved sensory reactions. Functional sensory recovery outcomes were defined by Pogrel's criteria, Medical Research Council Scale grades, and functional sensory recovery. In each group, all patients improved after the operation. However, the operation time was significantly shorter for an interpositional collagen allograft repair as compared to that for a direct perineurial repair with a vein graft cuff. Conclusions: There were no statistically significant differences between the two repair Methods, except for the operation time. Both methods led to satisfactory results for all criteria. From an economic point of view, direct perineurial repair with a vein graft cuff is meaningful; however, the esthetic effect on the donor site should be considered. Conversely, interpositional collagen allograft repair has the advantage of a greatly shortened operation time. [ABSTRACT FROM AUTHOR]

Introduction: A critical appraisal of the surgical results of paraclinoid aneurysms is essential in the flow diverters era.This study overviews the data of a three-decade surgical series of paraclinoid aneurysms while focusing on their technical remarks. Methods: Overall data of a surgical consecutive series of paraclinoid aneurysms treated between 1993 and 2021 were retrospectively reviewed. Aneurysms were classified according to size and projection. Indications for surgery were different based on the availability of endovascular techniques, especially flow diverter, at the time of treatment. A statistical comparison between ruptured and unruptured aneurysms was accomplished. Results: 58 patients were operated upon. Ophthalmic aneurysms were 68%, giant aneurysms 20%, and ruptured aneurysms 45%. Clipping and bypass were executed in 91% and 9% of cases, respectively. An mRS of 0–2 was achieved in 77% of patients, independently by the clinical onset. The mortality rate was 5%. Visual field was improved or unchanged in 71% of elective patients, whereas the incidence of de novo third and sixth cranial nerves deficit was 8% and 5%, respectively. On an average follow-up of 53.3 ± 38 months, a complete and durable aneurysm exclusion was achieved in 91.3% of patients with a single surgery. Conclusions: Microneurosurgery is still a valuable treatment option for selected ruptured and unruptured paraclinoid aneurysms. In our experience, it has proven to be definitive and durable, with acceptable morbidity and mortality. Clipping is the treatment of choice in most surgical cases, achieving a good visual outcome in symptomatic patients.

This article reviews the evolution of microneurosurgical anatomy (MNA) with special reference to the development of anatomy, surgical anatomy, and microsurgery. Anatomy can be said to have started in the ancient Greek era with the work of Hippocrates, Galen, and others as part of the pursuit of natural science. In the sixteenth century, Vesalius made a great contribution in reviving Galenian knowledge while adding new knowledge of human anatomy. Also in the sixteenth century, Ambroise Paré can be said to have started modern surgery. As surgery developed, more detailed anatomical knowledge became necessary for treating complicated diseases. Many noted surgeons at the time were also anatomists eager to spread anatomical knowledge in order to enhance surgical practice. Thus, surgery and anatomy developed together, with advances in each benefiting the other. The concept of surgical anatomy evolved in the eighteenth century and became especially popular in the nineteenth century. In the twentieth century, microsurgery was introduced in various surgical fields, starting with Carl O. Nylen in otology. It flourished and became popularized in the second half of the century, especially in the field of neurosurgery, following Jacobson and Suarez's success in microvascular anastomosis in animals and subsequent clinical application as developed by M.G. Yasargil and others. Knowledge of surgical anatomy as seen under the operating microscope became important for surgeons to perform microneurosurgical procedures accurately and safely, which led to the fuller development of MNA as conducted by many neurosurgeons, among whom A.L. Rhoton, Jr. might be mentioned as representative. [ABSTRACT FROM AUTHOR]

Operating microscopes and adjunctive technologies are continually refined to advance microneurosurgical care. How frequently these advances are used is unknown. In the present study, we assessed the international adoption of microneurosurgical technologies and discussed their value. A 27-question electronic survey was distributed to cerebrovascular neurosurgeon members of U.S., European, and North American neurosurgical societies and social media networks of cerebrovascular and skull base neurosurgeons. The survey encompassed the surgeons' training background, surgical preferences, and standard microneurosurgical practices. Of the respondents, 56% (53 of 95) were attendings, 74% (70 of 95) were in their first 10 years of practice, and 67% (63 of 94) practiced at an academic teaching hospital. Vascular, endovascular, and skull base fellowships had been completed by 38% (36 of 95), 27% (26 of 95), and 32% (30 of 95) of the respondents, respectively. Most respondents did not use an exoscope (78%; 73 of 94), a mouthpiece (61%; 58 of 95), or foot pedals (56%; 55 of 94). All 95 respondents used a microscope, and 71 (75%) used Zeiss microscopes. Overall, 57 neurosurgeons (60%) used indocyanine green for aneurysms (n = 54), arteriovenous malformations (n = 43), and dural arteriovenous fistulas (n = 42). Most (80%; 75 of 94) did not use fluorescence. The respondents with a vascular-focused practice more commonly used indocyanine green, Yellow 560 fluorescence, and intraoperative 2-dimensional digital subtraction angiography. The respondents with a skull base–focused practice more commonly used foot pedals and an endoscope-assist device. The results from the present survey have characterized the current adoption of operative microscopes and adjunctive technologies in microneurosurgery. Despite numerous innovations to improve the symbiosis between neurosurgeon and microscope, their adoption has been underwhelming. Future advances are essential to improve surgical outcomes. [ABSTRACT FROM AUTHOR]

Background: Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare and have characteristics differentiating them from other intracranial aneurysms. Their microsurgical management is challenging and requires different strategies. In this article, we review the surgical anatomy of the A1 segment of the ACA with cadaveric dissections and describe the microsurgical management of complex A1 aneurysms with illustrative cases. Methods: A right pterional craniotomy and Sylvian dissection were performed on a formalin-fixed and siliconeinjected cadaver head to depict the key anatomic structures and surgical corridors for microsurgical clipping of A1 segment aneurysms. The microneurosurgical management of ruptured and unruptured aneurysms of the A1 segment of the ACA is described with case illustrations. Results: The A1 segment of the ACA can be subdivided into proximal, middle, and distal subsegments, the former having abundant perforating branches. Both patients treated with microsurgical clipping had excellent and durable outcomes and postoperative cerebral angiograms showed complete aneurysm occlusion. Conclusion: Small A1 aneurysms may require early treatment as their rupture risk appears to be higher. A1 aneurysms are usually embedded in perforators, especially those arising from the proximal A1 subsegment, and require careful distal to proximal microdissection and strategic placement of the aneurysm clip blades. The approach, arachnoid dissection, and angles of attack are carefully planned after accounting for the aneurysm dome projection, precise location of the aneurysm neck and perforators, and the presence or absence of subarachnoid hemorrhage. [ABSTRACT FROM AUTHOR]

Koos grade IV vestibular schwannomas (VS) (maximum diameter > 3 cm) compress the brainstem and displace the fourth ventricle. Microsurgical resection with attention to the right balance between preservation of function and maximal tumor removal is the treatment of choice. Our series consists of 60 consecutive patients with unilateral VS, operated on from December 2010 to July 2019. All patients underwent microsurgical removal via the retrosigmoid approach. The adherence of VS' capsule to the surrounding nervous structures and the excessive tendency of tumor to bleed during debulking, because of a redundant vascular architecture, was evaluated by reviewing video records. Microsurgical removal of tumor was classified as total (T), near-total (NT: residue < 5%), subtotal (ST: residue 5–10%), or partial (P: residue > 10%). Maximal mean tumor diameter was 3,97 cm (SD ± 1,13; range 3,1–5,8 cm). Preoperative severely impaired hearing or deafness (AAO-HNS classes C–D) was present in 52 cases (86,7%). Total or NT resection was accomplished in 46 cases (76,7%), 65,8% in cases with, and 95,4% without tight adhesion of capsule to nervous structures (p < 0,001). Endoscopic-assisted microsurgical removal of VS in the IAC was performed in 23 patients: in these cases, a T resection was obtained in 78,3% versus 45,9% of microsurgery only (p < 0,001). The capsule of VS was tightly adherent to nervous structures in 63,3% of patients, whereas hypervascular high-bleeding tumors represented 56,7%. Hearing preservation was possible in 2 out of 8 patients with preoperative class B hearing. At last follow-up, 34 (56,7%) patients had a normal postoperative FN outcome (HBI), 9 (15,0%) were HBII, 8 (13,3%) HBIII, and 9 (15,0%) HBIV. The total NT resection of solid and low-bleeding VS, without tight capsule adhesion, was associated with better FN outcome. Mortality was zero; permanent complications were observed in 2 cases (diplopia, hydrocephalus), transient in 9. Microsurgery of Koos grade IV VS seems to be associated with more than acceptable functional results, with high rate of T and NT removal of tumor. Long-term FN results seem to be worse in patients with cystic Koos grade IV VS, in cases with tight capsule adherences to nervous structures and in high-bleeding tumors. [ABSTRACT FROM AUTHOR]

Introduction: In this microneurosurgical and anatomical study, we characterized the superficial anastomosing veins of the human brain cortex in human specimens.Material and Methods: We used 21 brain preparations fixed in formalin (5%) that showed no pathological changes and came from the autopsy sections. The superficial veins were dissected out of the arachnoid with the aid of a surgical microscope.Results: We dissected nine female and 12 male brain specimens, with an average age of 71 ± 11 years (range 51–88 years). We classified the superficial veins in five types: (I) the vein of Trolard as the dominat vein; (II) the vein of Labbé as the dominant vein; (III) a dominant sylvian vein group, and the veins of Trolard and Labbé nonexistent or only rudimentary present without contact to the Sylvian vein group; (IV) very weak sylvian veins with the veins of Trolard and Labbé codominant; and V) direct connection of Trolard and Labbé bypassing the Sylvian vein group. The vein of Trolard was dominant (Type I) in 21.4% and the vein of Labbé (Type II) in 16.7%. A dominant sylvian vein group (Type III) was found in 42.9%. Type IV and Type V were found in 14.3 and 4.7% respectively.Conclusion: No systematic description or numerical distribution of the superior anastomotic vein (V. Trolard) and inferior anastomotic vein (V. Labbé) has been found in the existing literature. This study aimed to fill this gap in current literature and provide data to neurosurgeons for the practical planning of surgical approaches.

Abstract Background The prognosis of recovery following microneurosurgery for injured lingual nerves varies among individual cases. This study aimed to investigate if recovery ratios of sensory and taste functions are improved by the microneurosurgery within 6 months after lingual nerve injury. Methods We retrospectively assessed 70 patients who underwent microneurosurgery at the Wakayama Medical University Hospital for lingual nerve injuries between July 2004 and December 2016. Sensory and taste functions in lingual nerves were preoperatively evaluated using a static two-point discrimination test, an intact superficial pain/tactile sensation test, and a taste discrimination test. They were evaluated again at 12 and at 24 months postoperatively. The abundance ratio of Schwann cells in the excised traumatic neuromas was analyzed with ImageJ software following immunohistochemistry with anti S-100β antibody. Results In early cases (microneurosurgery within 6 months after the injury), recovery ratios of sensory and taste functions were not significantly different at 24 months after microneurosurgery compared with later cases (microneurosurgery more than 6 months after the injury). Meanwhile, the ratio of patients with taste recovery within 12 months after microneurosurgery was significantly decreased in late cases compared with early cases. The abundance ratio of Schwann cells in traumatic neuroma was also significantly lower in later cases. Conclusion Microneurosurgery more than 6 months after lingual nerve injury did not lead to decreased recovery ratio of sensory and taste functions, but it did lead to prolonged recovery of taste. This delay may be associated with a decrease in the abundance ratio of Schwann cells in traumatic neuromas.

Background: Micro-arteriovenous malformations (mAVM), defined with a nidus smaller than one centimeter, can lead to intracranial hemorrhage. Surgery can be curative, but precise intra-operative localization of the nidus is often challenging. Finding the mAVM is particularly important when in an eloquent area. Due to their small size, mAVMs that are diagnosed on high quality angiography (occult on non-invasive imaging) may not be seen with intra-operative image guidance systems. Time-resolved 3D angiography (4D DSA) fuses the 3D volumes from different angiographic acquisition phases, and may help with mAVM localization. To illustrate the utility of 4D DSA in the localization of mAVMs for pre-operative surgical planning and during intra-operative resection.Methods: We present 4 surgically managed cases of ruptured paracentral mAVM where 4D DSA proved useful. First, 3D FLAIR MRI was used for cortical surface segmentation.4D DSA was then used to select two 3D volumes; one at time of maximal shunting (to show the mAVM nidus) and one with maximal venous filling (to show normal venous anatomy). These were merged using a neuronavigation system as 3D objects, fused to the 3D FLAIR volume, and used pre- and intra-operatively to precisely locate the mAVM.Results: Intra-operatively, segmentation of sulco-gyral and normal venous anatomy were used to confirm the accuracy of surgical planning. In all cases, the mAVM at ‘maximal shunt’ time guided the dissection to precisely locate the nidus. There were no instances of neurological deterioration with surgery, and complete resection was confirmed by indocyanine green fluorescent angiography, followed by delayed (3 months) catheter angiography.Conclusions: 4D DSA may be useful for surgical planning and precise intra-operative localization of mAVMs.

Background: Intraventricular tumors pose a surgical challenge because of the difficulty in reaching their deep location through safe corridors and their adherence or proximity to vital neurovascular structures. Although microneurosurgery is the mainstay of surgical management, neuroendoscopy aided by adjuncts, namely, navigation and ultrasonic aspirators, has made a great contribution to improving surgical results.Objective: This article reviews the experience of a neurosurgical unit with endoscopic procedures for intraventricular tumors. The current indications, benefits, and complications of neuroendoscopy are described.Materials and Methods: This is a retrospective, observational study of lateral and third ventricular tumors tackled either purely with an endoscope or with its assistance over 19 years in a single unit at Bombay Hospital Institute of Medical Sciences, Mumbai.Results: Of a total of 247 operated patients with intraventricular tumors, 85 cases operated using an endoscope were included. The majority of the patients had a tumor in the third ventricle (n = 62), whereas 23 patients had tumor in the lateral ventricle. The most common pathologies were colloid cyst and arachnoid cyst (n = 18). An endoscope was used for microsurgical assisted excision of tumors in 31 cases, biopsy in 24, cyst fenestration in 23, and pure endoscopic excision in seven cases.Conclusion: Microsurgery remains the gold standard for the removal of giant, vascular intraventricular tumors. However, endoscopic fenestration or excision of cysts and biopsy have become better alternatives in many cases. Endoscope-assisted microsurgery affords safety and helps in achieving a more complete excision. [ABSTRACT FROM AUTHOR]

Aneurysms of the vertebrobasilar system remain among the most challenging subsets of aneurysms to treat with an open surgical approach. Since Charles Drake's pioneering work in the 1960s, several advances in microsurgical techniques have improved outcomes and feasibility in the open surgical management of these aneurysms. In parallel, the field of endovascular neurosurgery has provided several safe and effective treatment options. Multiple trials have suggested that endovascular therapy for aneurysms of the vertebrobasilar system is superior to open surgical management in most cases. In some instances, however, open surgical management likely represents a more effective and durable option relative to endovascular therapy. Therefore, continued training of future cerebrovascular specialists in open surgery of vertebrobasilar aneurysms remains crucial. With widespread utilization of endovascular techniques, however, proper exposure of trainees to such aneurysms is growing increasingly difficult. In this review, we discuss the recent advances in the endovascular management of vertebrobasilar aneurysms while also emphasizing the continued importance of open microneurosurgery in such cases. [ABSTRACT FROM AUTHOR]

Background: Although leptomeningeal melanin pigmentation is well-known, it is not described in the neurosurgical literature. Dark pigmentation native to these transparent membranes might have microsurgical relevance in identifying a plane of dissection.Objective: To describe the prevalence of leptomeningeal pigmentation and determine whether its recognition helps during microsurgical excision of extra-axial brain tumors.Materials and Methods: : This was a prospective cross-sectional observational study in cadavers and neurosurgical patients. Eight adult cadaveric brains were examined for leptomeningeal pigmentation and biopsies taken for histological studies. A total of 126 patients undergoing surgery for cerebellopontine angle and suprasellar lesions were included in the clinical study. The surgeon determined whether the recognition of pigmentation was useful during microneurosurgical arachnoid dissection.Results: Seven of 8 cadavers (87.5%) had leptomeningeal pigmentation on the ventral pons, optic chiasm, lamina terminalis, olfactory tract, and gyrus rectus and infrequently on the cerebral convexities. The prevalence of pigmentation was 76.9% in the clinical study, was seen in all pediatric patients, and was significantly higher in males (P = 0.009), with no significant association with skin color. Immunochemistry identified the pigmentation as melanin. Recognition of this pigmentation was deemed to be useful during tumor excision in 78% of the cases.Conclusions: Leptomeningeal melanin pigmentation has a prevalence of 76% to 87% in the Indian population and is more often seen in younger males. It is most commonly identified overlying the ventral brain stem and optic chiasm. Recognition of its presence is helpful during arachnoid dissection during most cerebellopontine angle and suprasellar tumor resections. [ABSTRACT FROM AUTHOR]