Clinical efficacy and safety of neuroendoscopic surgery for severe thalamic hemorrhage with ventricle encroachment.

To summarize and analyze the clinical efficacy and safety of neuroendoscopic surgery (NES) in the treatment of patients for severe thalamic hemorrhage with ventricle encroachment (THVE). Eighty-three patients with severe THVE were treated in the Neurosurgery Department of Anqing Hospital Affiliated to Anhui Medical University from July 2019 to August 2021. Our study was approved by the ethics committee. The patients were randomly divided into NES group and extraventricular drainage (EVD) group. The hospital stay, Glasgow coma scale (GCS) scores on the 1st and 14th days postoperatively, the incidence of intracranial infections, and the clearance of postoperative hematomas were compared and analyzed between the two groups. The patients had follow-up evaluations 6 months postoperatively. The prognosis was evaluated based on the activity of daily living (ADL) score. A head CT or MRI was obtained to determine whether there was hydrocephalus, cerebral infarction, or other related complications. Eighty-three patients were randomly divided into 41 cases of NES group and 42 cases of EVD group. The length of postoperative hospital stay was 17.42 ± 1.53 days, the GCS scores were 6.56 ± 0.21, and 10.83 ± 0.36 on days 1 and 14, respectively; intracranial infections occurred in 3 patients (7.31%) and the hematoma clearance rate was 83.6 ± 5.18% in the NES group, all of which were significantly better than the EVD group (P < 0.05). After 6 months of follow-up, 28 patients (68.29%) had a good prognosis, 5 patients (12.19%) died, and 4 patients (9.75%) had hydrocephalus in the NES group. In the EVD group, the prognosis was good in 15 patients (35.71%), 12 patients (28.57%) died, and 17 patients (40.47%) had hydrocephalus. The prognosis, mortality rate, and incidence of hydrocephalus in the NES group were significantly better than the EVD group (P < 0.05). Compared to traditional EVD, NES for severe THVE had a higher hematoma clearance rate, and fewer intracranial infections and patients with hydrocephalus, which together improve the clinical prognosis and is thus recommended for clinical use.

Integration of Comprehensive Metrics into the PsT1 Neuroendoscopic Training System.

OBJECTIVE: Metric-based surgical training can be used to quantify the level and progression of neurosurgical performance to optimize and monitor training progress. Here we applied innovative metrics to a physical neurosurgery trainer to explore whether these metrics differentiate between different levels of experience across different tasks. METHODS: Twenty-four participants (9 experts, 15 novices) performed 4 tasks (dissection, spatial adaptation, depth adaptation, and the A-B-A task) using the PsT1 training system. Four performance metrics (collision, precision, dissected area, and time) and 6 kinematic metrics (dispersion, path length, depth perception, velocity, acceleration, and motion smoothness) were collected. RESULTS: For all tasks, the execution time (t) of the experts was significantly lower than that of novices (P < 0.05). The experts performed significantly better in all but 2 of the other metrics, dispersion and sectional area, corresponding to the A-B-A task and dissection task, respectively, for which they showed a nonsignificant trend towards better performance (P = 0.052 and P = 0.076, respectively). CONCLUSIONS: It is possible to differentiate between the skill levels of novices and experts according to parameters derived from the PsT1 platform, paving the way for the quantitative assessment of training progress using this system. During the current coronavirus disease 2019 pandemic, neurosurgical simulators that gather surgical performance metrics offer a solution to the educational needs of residents.

Endoscopic Subtemporal Epidural Key-Hole Approach: Quantitative Anatomic Analysis of Three Surgical Corridors.

BACKGROUND: The endoscope-assisted subtemporal key-hole epidural approach (ESKEA) has been recently described. The aim of this study was to measure working volumes and exposure of key areas of the middle cranial fossa provided by this approach. METHODS: Four fresh frozen cadaver heads were dissected to analyze 3 modular corridors (1A, 1B, and 2) harvested through ESKEA. A step-by-step dissection was performed, and key anatomic landmarks were recorded. A GTxEyesII-ApproachViewer was used to quantify the working volume and exposure of 4 different regions (sphenoorbital, parasellar, superior petrous apex, and squamopetrous). For each corridor, 3 incremental degrees of temporal dural retraction (5, 10, and 15 mm) were tested. RESULTS: The working volume of all corridors progressively increased with degree of retraction: Corridors 1A, 1B, and 2 showed a gain in working volume of 21%, 27%, and 19% from 5 mm to 10 mm retraction, respectively, and a gain of 40%, 45%, and 44% from 5 mm to 15 mm retraction, respectively. The sphenoorbital area was exposed (27%-45%) through corridor 1A, and exposure significantly increased with the degree of retraction. Corridor 1B provided optimal exposure of parasellar areas (86%-100%) and superior petrous apex (70%-87%) regardless of the degree of retraction. The squamopetrous area was satisfactorily addressed through corridor 2 (88%) only with the highest degree of retraction. CONCLUSIONS: ESKEA can be conceived as a modular approach: the 3 surgical corridors have specific working volumes, which are clearly influenced by the degree of temporal lobe retraction, and provide exposure of different middle cranial fossa areas.

Endoscopic versus stereotactic biopsies of intracranial lesions involving the ventricles.

Stereotactic biopsies of ventricular lesions may be less safe and less accurate than biopsies of superficial lesions. Accordingly, endoscopic biopsies have been increasingly used for these lesions. Except for pineal tumors, the literature lacks clear, reliable comparisons of these two methods. All 1581 adults undergoing brain tumor biopsy from 2007 to 2018 were retrospectively assessed. We selected 119 patients with intraventricular or paraventricular lesions considered suitable for both stereotactic and endoscopic biopsies. A total of 85 stereotactic and 38 endoscopic biopsies were performed. Extra procedures, including endoscopic third ventriculostomy and tumor cyst aspiration, were performed simultaneously in 5 stereotactic and 35 endoscopic cases. In 9 cases (5 stereotactic, 4 endoscopic), the biopsies were nondiagnostic (samples were nondiagnostic or the results differed from those obtained from the resected lesions). Three people died: 2 (1 stereotactic, 1 endoscopic) from delayed intraventricular bleeding and 1 (stereotactic) from brain edema. No permanent morbidity occurred. In 6 cases (all stereotactic), additional surgery was required for hydrocephalus within the first month postbiopsy. Rates of nondiagnostic biopsies, serious complications, and additional operations were not significantly different between groups. Mortality was higher after biopsy of lesions involving the ventricles, compared with intracranial lesions in any location (2.4% vs 0.3%, p = 0.016). Rates of nondiagnostic biopsies and complications were similar after endoscopic or stereotactic biopsies. Ventricular area biopsies were associated with higher mortality than biopsies in any brain area.

Optimal surgical indications of endoscopic surgery for traumatic acute subdural hematoma in elderly patients based on a single-institution experience.

Recently, treatment of acute subdural hematoma (ASDH) by minimally invasive surgery with endoscopy has been successfully demonstrated. However, few case series are available on this procedure for ASDH, and the surgical indication has not been established. We retrospectively analyzed the data of patients (n = 26) aged 65 years or older who underwent endoscopic surgery (ES) for ASDH at our institution between January 2011 and March 2019. We then evaluated the surgical outcomes and procedure-related complications in patients who underwent ES. The mean hematoma reduction rate was over 90%. Percentage of favorable outcomes at discharge was 69.2% in ES-treated patients. The presence of a skull fracture, subarachnoid hemorrhage, midline shift/subdural hematoma thickness ratio > 1.0, and early surgery were associated with postoperative IPHs in patients who underwent ES or conventional surgery for ASDH. The present study revealed that ES for elderly patients with ASDH is likely to be an efficient and safe procedure when patients are selected appropriately. However, ES is not recommended in patients with significant IPHs on initial CT scan. Additionally, ES should be carefully considered in cases with the factors, where IPHs may progress following surgery.

Early practices in endonasal skull base surgery during the COVID-19 pandemic: a global survey.

OBJECTIVE: During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, endoscopic endonasal surgery (EES) is feared to be a high-risk procedure for the transmission of coronavirus disease 2019 (COVID-19). Nonetheless, data are lacking regarding the management of EES during the pandemic. The object of this study was to understand current worldwide practices pertaining to EES for skull base/pituitary tumors during the SARS-CoV-2 pandemic and provide a basis for the formulation of guidelines. METHODS: The authors conducted a web-based survey of skull base surgeons worldwide. Different practices by geographic region and COVID-19 prevalence were analyzed. RESULTS: One hundred thirty-five unique responses were collected. Regarding the use of personal protective equipment (PPE), North America reported using more powered air-purifying respirators (PAPRs), and Asia and Europe reported using more standard precautions. North America and Europe resorted more to reverse transcriptase-polymerase chain reaction (RT-PCR) for screening asymptomatic patients. High-prevalence countries showed a higher use of PAPRs. The medium-prevalence group reported lower RT-PCR testing for symptomatic cases, and the high-prevalence group used it significantly more in asymptomatic cases.Nineteen respondents reported transmission of COVID-19 to healthcare personnel during EES, with a higher rate of transmission among countries classified as having a medium prevalence of COVID-19. These specific respondents (medium prevalence) also reported a lower use of airborne PPE. In the cases of healthcare transmission, the patient was reportedly asymptomatic 32% of the time. CONCLUSIONS: This survey gives an overview of EES practices during the SARS-CoV-2 pandemic. Intensified preoperative screening, even in asymptomatic patients, RT-PCR for all symptomatic cases, and an increased use of airborne PPE is associated with decreased reports of COVID-19 transmission during EES.

The therapeutic effects of craniotomy versus endoscopic-assisted trepanation drainage for isolated chronic subdural haematoma (ICSH): A single-centre long-term retrospective comparison study.

BACKGROUND: Isolated chronic subdural hematoma (ICSH), as a special rare species, has great controversy over its treatment. A retrospective analysis was performed to compare craniotomy with endoscopic-assisted trepanation drainage (EATD) of ICSH. METHODS: The data of ICSH patients for craniotomy or EATD from January 2011 to April 2019 were retrospectively collected and analysed. Of 106 patients, 49 and 57 patients received craniotomy and EATD treatment respectively. Recurrence rate, morbidity and mortality rate were the main outcome. RESULT: There was no recurrence in both groups. The morbidity rate of the EATD group (2/57, 3.5%) was significantly lower than that of the craniotomy group (17/49, 34.7%, p = 0.0033). There was no death in the EATD group, but 3 cases died of operative produce in the craniotomy group. The average operation time of the craniotomy group (95.3min) was significantly longer than that of the EATD group (66.5min, P = 0.0032). Craniotomy group had more intraoperative blood loss (213.2ml) than EATD group (34.5ml, P = 0.0044). EATD patients had shorter hospital stay and recovered faster. CONCLUSIONS: Compared with craniotomy, EATD is a more effective and safer method for the treatment of ICSH.

Ventilated Upper Airway Endoscopic Endonasal Procedure Mask: Surgical Safety in the COVID-19 Era.

BACKGROUND: COVID-19 poses a risk to the endoscopic skull base surgeon. Significant efforts to improving safety have been employed, including the use of personal protective equipment, preoperative COVID-19 testing, and recently the use of a modified surgical mask barrier. OBJECTIVE: To reduce the risks of pathogen transmission during endoscopic skull base surgery. METHODS: This study was exempt from Institutional Review Board approval. Our study utilizes a 3-dimensional (3D)-printed mask with an anterior aperture fitted with a surgical glove with ports designed to allow for surgical instrumentation and side ports to accommodate suction ventilation and an endotracheal tube. As an alternative, a modified laparoscopic surgery trocar served as a port for instruments, and, on the contralateral side, rubber tubing was used over the endoscrub endosheath to create an airtight seal. Surgical freedom and aerosolization were tested in both modalities. RESULTS: The ventilated mask allowed for excellent surgical maneuverability and freedom. The trocar system was effective for posterior surgical procedures, allowing access to critical paramedian structures, and afforded a superior surgical seal, but was limited in terms of visualization and maneuverability during anterior approaches. Aerosolization was reduced using both the mask and nasal trocar. CONCLUSION: The ventilated upper airway endoscopic procedure mask allows for a sealed surgical barrier during endoscopic skull base surgery and may play a critical role in advancing skull base surgery in the COVID-19 era. The nasal trocar may be a useful alternative in instances where 3D printing is not available. Additional studies are needed to validate these preliminary findings.

Efficacy and safety of four interventions for spontaneous supratentorial intracerebral hemorrhage: a network meta-analysis.

OBJECT: To investigate the efficacy and safety of four interventions of spontaneous intracerebral hemorrhage simultaneously. METHODS: PubMed, EmBase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) investigating endoscopic surgery (ES), minimally invasive puncture surgery (MIPS), conventional craniotomy (CC), and/or conservative medical treatment (CMT). Good functional outcome, death, and hemorrhage recurrence rates were evaluated by a network meta-analysis. RESULTS: 20 RCTs with 3603 patients were included. Compared with CMT, a higher rate of good functional outcome was found after ES (RR=2.21, 95% CI 1.37 to 3.55) and MIPS (RR=1.47, 95% CI 1.24 to 1.73). Both ES (RR=0.62, 95% CI 0.44 to 0.86) and MIPS (RR=0.72, 95% CI 0.58 to 0.90) markedly reduced the rate of death. However, there was no significant difference in efficacy and safety between ES and MIPS. The top ranked P score for the efficacy outcome was for ES (P score=0.9810). ES (P-score=0.0709) ranked lowest for the primary safety outcome. There was a higher risk of hemorrhage recurrence after CC (RR=3.80, 95% CI 1.90 to 7.63) and MIPS (RR=2.86, 95% CI 1.70 to 4.82) compared with CMT whereas no significant difference was found for ES (RR=1.46, 95% CI 0.53 to 4.02). CONCLUSIONS: The results suggest that both ES and MIPS significantly improve neurological function and reduce the risk of death compared with CMT, and there is no significant difference between ES and MIPS. Ranking of P scores revealed that ES may be the most optimal intervention to improve functional outcome and prevent death. This needs to be evaluated further.

Assessment of the Reliability of the Fiberoptic Endoscopic Evaluation of Swallowing as an Outcome Measure in Patients Undergoing Revision Anterior Cervical Discectomy and Fusion.

BACKGROUND: Dysphagia is one of the most common complications of anterior cervical spine surgery, and there is a need to establish that the means of testing for it are reliable and valid. The objective of this study was to measure observer variability of the fiberoptic endoscopic evaluation of swallowing (FEES) test, specifically when used for evaluation of dysphagia in patients undergoing revisionary anterior cervical decompression and fusion (ACDF). METHODS: Images from patients undergoing revision ACDF at a single institution were collected from May 1, 2010, through July 1, 2014. Two senior certified speech pathologists independently evaluated the swallowing function of patients preoperatively and at 2 weeks postoperatively. Their numeric evaluations of the Rosenbeck Penetration-Aspiration Scale and the Swallowing Performance Scale during the FEES were then compared for interrater reliability. RESULTS: Positive agreement between raters was 94% for the preoperative Penetration-Aspiration Scale (prevalence-adjusted bias-adjusted κ, 0.77). The postoperative Penetration-Aspiration Scale showed reliability coefficients for κ, Kendall's W, and intraclass correlation coefficient (ICC) of 0.34 (fair agreement), 0.70 (extremely strong agreement), and 0.35 (poor agreement), respectively. The preoperative Swallowing Performance Scale showed strong agreement, with a Kendall's W coefficient of 0.68, and fair reliability, with an ICC of 0.40. The postoperative Swallowing Performance Scale indicated extremely strong agreement between raters, with a Kendall's W of 0.82, and good agreement, with an ICC of 0.53. CONCLUSIONS: The FEES test appears to be a reliable assessor of dysphagia in patients undergoing ACDF and may be a useful measure for exploring outcomes in this population.

Three-Dimensional, High-Definition Exoscopic Anterior Cervical Discectomy and Fusion: A Valid Alternative to Microscope-Assisted Surgery.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) remains one of the most commonly taught procedures during residency and one of the most frequently performed by neurosurgeons. Neurosurgeons use microscopes to perform surgery and to train other surgeons. Although the microscope provides excellent illumination and magnification, its use will be limited to 2 people: the surgeon and the assistant. Consequently, the scrub nurse and residents watching 2-dimensional images on monitors will have a reduced perception of the surgical field depth and anatomical details. The exoscope has been introduced as an alternative to microscopes and endoscopes. We used a 3-dimensional (3D), high-definition exoscope (3D Vitom [Karl Storz, Tuttlingen, Germany]) in 2 patients undergoing 2-level ACDF for cervical myeloradiculopathy. METHODS: The exoscope was used during soft tissue dissection, discectomy, osteophytectomy, and cage insertion. Microsurgical drilling of the posterior osteophytes, which will usually require adequate magnification and proper microscope angulation, was also performed using the exoscope. RESULTS: The exoscope provided a 3D view of the surgical field similar to that provided by a microscope and allowed us to effectively and safely perform the required surgical steps. The main advantage of 3D exoscope-assisted surgery, compared with microscope-assisted surgery, is the possibility to generate videos with a similar view and image quality as perceived by the surgeon. Therefore, the didactic capabilities of exoscopic videos are greater than those provided by microscopic videos. Exoscopes are also smaller compared with microscopes, allowing for comfortable use from the early surgical steps to device implantation. CONCLUSION: We believe that exoscope-assisted surgery could become a safe and effective alternative to microscope-assisted surgery in ACDF.

Breadth and Depth: Three-Dimensional Endoscopic Field of View: Two-Dimensional Versus Three-Dimensional Endoscopic Field of View.

BACKGROUND: Three-dimensional (3D) endoscopy is an emerging tool in ear-nose-throat (ENT) and skull base surgery with the benefit of providing real-time depth perception. Several investigators have reported that the field of view (FOV) is reduced in 3D endoscopes compared with regular 2-dimensional (2D) endoscopes. Thus, we objectively compared the FOV of 2D and 3D endoscopes. METHODS: Using a standard 2D and 2 different 3D ENT endoscopes, images were captured of 1-mm graph paper from a set distance of 6 cm. The FOV was calculated from these images and compared among the endoscopes. RESULTS: The VisionSense 3D endoscope had a slightly smaller FOV (9.1 cm vs. 10.1 cm; -9.9%), and the Karl Storz 3D endoscope showed a slightly larger FOV (10.4 cm vs. 10.1 cm; +3.0%). However, the results were complicated by the different-shaped images produced by the 3D endoscopes. CONCLUSION: The differences in the FOV between the 2D and 3D endoscopes used in ENT surgery were not clinically significant. Thus, the FOV should not be considered a limitation of 3D technology.

Minimally invasive endoscopic hematoma evacuation vs best medical management for spontaneous basal-ganglia intracerebral hemorrhage.

BACKGROUND: We conducted a case-control study to assess the relative safety and efficacy of minimally invasive endoscopic surgery (MIS) for clot evacuation in patients with basal-ganglia intracerebral hemorrhage (ICH). METHODS: We evaluated consecutive patients with acute basal-ganglia ICH at a single center over a 42-month period. Patients received either best medical management according to established guidelines (controls) or MIS (cases). The following outcomes were compared before and after propensity-score matching (PSM): in-hospital mortality; discharge National Institutes of Health Stroke Scale score; discharge disposition; and modified Rankin Scale scores at discharge and at 3 months. RESULTS: Among 224 ICH patients, 19 (8.5%) underwent MIS (mean age, 50.9±10.9; 26.3% female, median ICH volume, 40 (IQR, 25-51)). The interventional cohort was younger with higher ICH volume and stroke severity compared with the medically managed cohort. After PSM, 18 MIS patients were matched to 54 medically managed individuals. The two cohorts did not differ in any of the baseline characteristics. The median ICH volume at 24 hours was lower in the intervention group (40 cm3 (IQR, 25-50) vs 15 cm3 (IQR, 5-20); P<0.001). The two cohorts did not differ in any of the pre-specified outcomes measures except for in-hospital mortality, which was lower in the interventional cohort (28% vs 56%; P=0.041). CONCLUSIONS: Minimally invasive endoscopic hematoma evacuation was associated with lower rates of in-hospital mortality in patients with spontaneous basal-ganglia ICH. These findings support a randomized controlled trial of MIS versus medical management for ICH.

The Endoscopic Endonasal Approach to Craniovertebral Junction Pathologies: Surgical Skills and Anatomical Study.

INTRODUCTION: Surgical anterior decompression is the treatment of choice for symptomatic irreducible ventral craniovertebral junction (CVJ) compression. Along with the classic transoral approach, the endoscopic endonasal approach has evolved and is gaining growing success. MATERIALS AND METHODS: In this work we discuss the surgical technique, give a complete step-by-step description of dissection of the craniovertebral junction and report a specific case of endoscopic endonasal odontoidectomy with use of a high-definition (HD) three-dimensional (3D) endoscope. DISCUSSION: The extended endonasal approach exploits an anatomical corridor to the odontoid process, involving only a small incision in the nasopharynx and sparing palate integrity. The most important limitation of the technique is 2D visualization, which hinders correct recognition of anatomical structures. CONCLUSION: The endoscopic endonasal route to the odontoid process has proven to be a feasible, safe and well-tolerated procedure. Anatomical study is very important for better understanding of the 3D anatomy of the CVJ and relation of critical neurovascular structures to specific bony and muscular landmarks.

Transoral Approach to the Craniovertebral Junction: A Neuronavigated Cadaver Study.

More than 100 years after the first description by Kanavel of a transoral-transpharyngeal approach to remove a bullet impacted between the atlas and the clivus [1], the transoral approach (TOA) still represents the 'gold standard' for surgical treatment of a variety of conditions resulting in anterior craniocervical compression and myelopathy [2, 3]. Nevertheless, some concerns-such as the need for a temporary tracheostomy and a postoperative nasogastric tube, and the increased risk of infection resulting from possible bacterial contamination and nasopharyngeal incompetence [4-6]-led to the introduction of the endoscopic endonasal approach (EEA) by Kassam et al. [7] in 2005. Although this approach, which was conceived to overcome those surgical complications, soon gained wide attention, its clear predominance over the TOA in the treatment of craniovertebral junction (CVJ) pathologies is still a matter of debate [3]. In recent years, several papers have reported anatomical studies and surgical experience with the EEA, targeting different areas of the midline skull base, from the olfactory groove to the CVJ [8-19]. Starting from these preliminary experiences, further anatomical studies have defined the theoretical (radiological) and practical (surgical) craniocaudal limits of the endonasal route [20-25]. Our group has done the same for the TOA [26, 27] and compared the reliability of the radiological and surgical lines of the two different approaches. Very recently, a cadaver study, with the aid of neuronavigation, tried to define the upper and lower limits of the endoscopic TOA [28].

Surgical Management of Moderate Basal Ganglia Intracerebral Hemorrhage: Comparison of Safety and Efficacy of Endoscopic Surgery, Minimally Invasive Puncture and Drainage, and Craniotomy.

OBJECTIVE: To date, no standard surgical procedure has been proven effective for intracerebral hemorrhage (ICH), particularly deep hematomas. This retrospective study evaluated the effectiveness and safety of endoscopic surgery, minimally invasive puncture and drainage, and craniotomy for treating moderate basal ganglia ICH. METHODS: Patients with basal ganglia ICH (N = 177) were divided into 3 groups based on therapeutic intervention as follows: endoscopic surgery group (n = 61), minimally invasive puncture and drainage group (n = 60), and craniotomy group (n = 56). Patient characteristics at admission were recorded. Operative time; blood loss during operation; evacuation rate; postoperative complications secondary to perihematomal edema, including rebleeding, infectious meningitis, pulmonary infection, gastrointestinal bleeding, and epilepsy; mortality; and Glasgow Outcome Scale scores were compared among the 3 groups. RESULTS: Minimally invasive puncture and drainage was the least traumatic procedure and had the shortest operative time, but it could not remove the hematoma quickly; moreover, it had the highest rebleeding rate. Craniotomy was effective in removing the hematoma but resulted in marked trauma and had the highest incidence of pulmonary infection. Endoscopic surgery was safer and more effective than the other 2 surgical methods, with greater improvement in neurologic outcomes and no change in mortality. CONCLUSIONS: Minimally invasive neuroendoscopic management has the advantages of direct vision, efficient hematoma evacuation, and relatively good results. Endoscopic surgery may be a more promising approach for the treatment of moderate basal ganglia ICH.

Minimally invasive approaches to aneurysms of the anterior circulation: selection criteria and clinical outcomes.

Over the last few decades, cerebrovascular surgery has gravitated towards a minimally invasive philosophy without compromising the foundational principles of patient safety and surgical efficacy. Enhanced radiosurveillance modalities and increased average life expectancy have resulted in an increased reported incidence of intracranial aneurysms. Although endovascular therapies have gained popularity in the recent years, microsurgical clipping continues to be of value in the management of these aneurysms owing to its superior occlusion rates, applicability to complex aneurysms and reduced retreatment rates. The concept of keyhole transcranial procedures has advanced the field significantly leading to decreased postoperative neurological morbidity and quicker recovery. The main keyhole neurosurgical approaches include the supraorbital craniotomy (SOC), lateral supraorbital craniotomy (LSOC), mini-pterional craniotomy (MPTC), mini-orbitozygomatic craniotomy and the mini anterior interhemispheric approach (MAIA). As these minimally invasive approaches can have an inherent limitation of a narrow viewing angle and low regional illumination, the use of endoscopic assistance in such procedures is being popularized. Neuroendoscopy can aid in the visualization of hidden neurovascular structures and inspection of the parent arterial segment without undue retraction of the lesion. This review focuses on the historical progression of the surgical management of intracranial aneurysms, the technical details of various minimally invasive approaches, patient selection and clinical outcomes of the anterior circulation aneurysms and useful tenets to avoid complications during these procedures. Meticulous preoperative planning to understand the patient's vascular anatomy, the orientation and relationship of the aneurysm to adjacent structures, use of neuronavigation guidance and endoscopic assistance if needed can lead to an optimal surgical outcome while minimizing neurological morbidity and mortality.

Utilization of intraoperative confocal laser endomicroscopy in brain tumor surgery.

Precise identification of tumor margins is of the utmost importance in neuro-oncology. Confocal microscopy is capable of rapid imaging of fresh tissues at cellular resolution and has been miniaturized into handheld probe-based systems suitable for use in the operating room. We aimed to perform a literature review to provide an update on the current status of confocal laser endomicroscopy (CLE) technology for brain tumor surgery. Aside from benchtop confocal microscopes used in ex vivo fashion, there are four CLE systems that have been investigated for potential application in the workflow of brain tumor surgery. Preclinical studies on animal tumor models and clinical studies on human brain tumors have assessed in vivo and ex vivo imaging approaches, suggesting that confocal microscopy holds promise for rapid identification of the characteristic (diagnostic) histological features of tumor and normal brain tissues. However, there are few studies assessing diagnostic accuracy sufficient to provide a definitive determination of the clinical and economical value of CLE in brain tumor surgery. Intraoperative real-time, high-resolution tissue imaging has significant clinical potential in the field of neuro-oncology. CLE is an emerging imaging technology that shows promise for improving brain tumor surgery workflow in in vivo and ex vivo studies. Future clinical studies are necessary to demonstrate clinical and economic benefit of CLE.

Quantitative analysis of the surgical exposure and surgical freedom between transcranial and transorbital endoscopic anterior petrosectomies to the posterior fossa.

OBJECT: This study proposes a variation of the transorbital endoscopic approach (TOEA) that uses the lateral orbit as the primary surgical corridor, in a minimally invasive fashion, for the posterior fossa (PF) access. The versatility of this technique was quantitatively analyzed in comparison with the anterior transpetrosal approach (ATPA), which is commonly used for managing lesions in the PF. METHODS: Anatomical dissections were carried out in 5 latex-injected human cadaveric heads (10 sides). During dissection, the PF was first accessed by TOEAs through the anterior petrosectomy, both with and without lateral orbital rim osteotomies (herein referred as the lateral transorbital approach [LTOA] and the lateral orbital wall approach [LOWA], respectively). ATPAs were performed following the orbital approaches. The stereotactic measurements of the area of exposure, surgical freedom, and angles of attack to 5 anatomical targets were obtained for statistical comparison by the neuronavigator. RESULTS: The LTOA provided the smallest area of exposure (1.51 ± 0.5 cm2, p = 0.07), while areas of exposure were similar between LOWA and ATPA (1.99 ± 0.7 cm2 and 2.01 ± 1.0 cm2, respectively; p = 0.99). ATPA had the largest surgical freedom, whereas that of LTOA was the most restricted. Similarly, for all targets, the vertical and horizontal angles of attack achieved with ATPA were significantly broader than those achieved with LTOA. However, in LOWA, the removal of the lateral orbital rim allowed a broader range of movement in the horizontal plane, thus granting a similar horizontal angle for 3 of the 5 targets in comparison with ATPA. CONCLUSIONS: The TOEAs using the lateral orbital corridor for PF access are feasible techniques that may provide a comparable surgical exposure to the ATPA. Furthermore, the removal of the orbital rim showed an additional benefit in an enhancement of the surgical maneuverability in the PF.