Endoscopy in aneurysm surgery

Fully endoscopic keyhole approach for intracranial aneurysm clipping: clinical outcomes and technical note

BACKGROUND

Surgical clipping is often utilized to treat intracranial aneurysms. The application of the endoscopy and keyhole approach in neurosurgery is increasing gradually in intracranial aneurysm occlusion. The aim of this study is to evaluate the role of fully endoscopic keyhole approach in clipping of intracranial aneurysms.

METHODS

We retrospectively analyzed four cases of intracranial aneurysms, including three cases of middle cerebral artery bifurcation aneurysms (M1) and one case of anterior communicating aneurysms (ACoA). Among them, the anterior communicating aneurysm underwent fully endoscopic clipping via supraorbital keyhole approach and the middle cerebral aneurysms underwent fully endoscopic clipping via mini-pterional keyhole approach. The clipped aneurysms were evaluated by Digital Subtraction Angiography (DSA).

RESULTS

All patients had satisfactory cerebral aneurysm clipping via the endoscopic keyhole approach. There was no cerebral hemorrhage, cerebral infarction, cerebral vasospasm. One case of intracranial infection was cured by active anti-infection. No recurrence of aneurysms after 6 months of follow-up.

CONCLUSION

With the advantages of the endoscopy and keyhole approach, the excellent visual field of the endoscope can reduce the influence of intracranial aneurysmal neck residual and perforating vessel. However, endoscopic clipping of intracranial aneurysms in narrow corridors requires a learning curve.

Clipping of anterior circulation aneurysms using fully endoscopic-assisted minimally invasive keyhole craniotomy: a clinical study and analysis

Endoscopy's ability to provide close observation, deep magnification, and multi-angle views has proven to be an effective tool for minimally invasive craniotomy in neurosurgery. However, no large case series have been published on the use of fully endoscopic-assisted minimally invasive keyhole craniotomy for clipping intracranial aneurysms (IAs). To evaluate the value of fully endoscopic-assisted minimally invasive keyhole craniotomy in the treatment of anterior circulation aneurysms. A retrospective analysis was conducted on 20 patients who underwent fully endoscopic-assisted minimally keyhole invasive craniotomy for clipping of IAs. A total of 9 anterior communicating artery (ACoA) aneurysms were clipped using the supraorbital keyhole approach (SKA). Additionally, 10 middle cerebral artery aneurysms (MCA) and 2 posterior communicating artery (PCoA) aneurysms were clipped using the pterional keyhole approach (PKA). The clipping success rate was 100% in all patients. Apart from one patient who experienced transient third cranial nerve palsy, one who developed an intracranial infection, and one who had a brief seizure, no other patients experienced serious complications. Except for one patient who had residual muscle weakness due to a preoperative basal ganglia hemorrhage, all other patients had a modified Rankin Scale (mRS) score of ≤ 1. Fully endoscopic-assisted minimally invasive keyhole craniotomy has promising applications in the treatment of anterior circulation aneurysms in Hunt-Hess grade 0-II, especially for unruptured aneurysms. Future multi-center studies are needed to confirm its broader applicability.

Clipping aneurysms via a fully endoscopic transcranial approach

Here we presented the initial experience of clipping aneurysms using fully endoscopic techniques and aimed to evaluate the safety and feasibility of fully endoscopic techniques for aneurysms. This was a retrospective single-center study in which patients were scheduled to undergo aneurysm clipping using fully endoscopic techniques. We collected patients' records, radiological neuroimaging, aneurysm-related variables and surgical procedures in detail, as well as postoperative outcomes. All patients were followed up for neurological examinations and computed tomography (CT) as well as computed tomography angiography (CTA) regularly after surgery. We reviewed the radiological and clinical data of 7patients who underwent aneurysm clipping via fully endoscopic techniques at our department from Jan. 2022 to Jul. 2024, including 2 middle cerebral artery aneurysms, 3 cerebral anterior communicating artery aneurysms, 1 anterior cerebral aneurysm and 1 ophthalmic aneurysm. No uncontrolled rupture of aneurysm occurred during operation. Postclipping endoscopic inspection as well as postoperative CTA demonstrated complete occlusion of the aneurysm and preservation of parent, branching, and perforating vessels. None postclipping cerebral infarction caused by branch or perforator compromise were observed after clipping. No mortality was recorded. Follow-up ranged from 1 to 10 months. Six patients (71.4%) showed excellent or good recoveries. The remaining patient recorded improved KPS. With the accumulation of experience and technological progress, the fully endoscopic technique could enable safe and effective clipping of an aneurysm, which provided valuable information for decision-making during surgery and shed a new light on aneurysms clipping.

The Pterional Keyhole Craniotomy Approach: A Historical Perspective

The pterional craniotomy is a workhorse of cranial surgery that provides access to the anterior and middle fossae. However, newer "keyhole" approaches, such as the micropterional or pterional keyhole craniotomy (PKC) can offer similar exposure for many pathologies while reducing surgical morbidity. The PKC is associated with shorter hospitalizations, reduced operative time, and superior cosmetic outcomes. Furthermore, it represents an ongoing trend toward smaller craniotomy size for elective cranial procedures. In this historical vignette, we trace the history of the PKC from its origins to its current role in the neurosurgeon's armamentarium.

Modern endoscopic skull base neurosurgery

INTRODUCTION

Since the early use of the endoscopic view for treating simple intrasellar pituitary adenomas, the skull base surgery has experienced an unprecedented revolution elevating the treatment of skull base lesions to the next level in proficiency and excellence of care.

METHODS

We have reviewed the preclinical and clinical evidence supporting the use of the endoscope in the treatment of skull base lesions. In this article, we aim to discuss and provide a wide view of the current indications and future perspectives of the endoscopic endonasal approaches (EEA) and of the endoscopic transcranial approaches.

RESULTS

As in the development of any other technique, EEA have gone through a transformation process from theoretical anatomic models to a pragmatic clinical use. Along the way, EEA have required several modifications, as well as pushbacks in the application of this technique in some indications. This process has resulted in the provision of an additional tool to the current surgical armamentarium that allows the skull base surgeon to face most challenging lesions along the skull base.

CONCLUSIONS

The judicious combination of transcranial and endoscopic-transnasal approaches warrants highest chances of achieving satisfactory tumors resection with a reduced risk of complications.

Anterior perforated substance region aneurysms: review of a series treated with microsurgical technique

Aneurysms arising from the distal carotid, proximal A1, and proximal M1 that project posteriorly and superiorly toward the anterior perforated substance (APS) are rare. Their open surgical treatment is particularly difficult due to poorly visualized origin of the aneurysm and the abundance of surrounding perforators. We sought to analyze the anatomical and clinical characteristics of APS aneurysms and discuss surgical nuances that can optimize visualization, complete neck clip obliteration, and preservation of adjacent perforators. Thirty-two patients with 36 APS aneurysms were surgically treated between November 2000 and September 2017. Patients were prospectively enrolled in a cerebral aneurysm database and their clinical, imaging, and surgical records were retrospectively reviewed. Twenty-seven aneurysms originated from the distal ICA, 7 from the proximal A1, and 2 from the proximal M1; 15 patients presented with subarachnoid hemorrhage. Careful intraoperative dissection revealed 4 aneurysms originating at the takeoff of a perforator; another 25 had at least 1 adherent perforator. All aneurysms were clipped except for one that was trapped. Postoperatively, 3 patients had radiographic infarctions in perforator territory with only 1 developing delayed clinical hemiparesis. Good outcome (modified Rankin Scale, 0-2) was achieved in 28 patients (88%). APS aneurysms present a challenging subset of aneurysms due to their complex anatomical relationship with surrounding perforators. These should be identified on preoperative imaging based on location and projection. Successful microsurgical clipping relies on optimization of the surgical view, meticulous clip reconstruction, preservation of all perforators, and electrophysiological monitoring to minimize ischemic complication.

A Cadaveric Anatomical Study on Anterior Communicating Artery Aneurysm Surgery by Extended Endoscopic Endonasal Approach

Background:

The use of minimally invasive approaches in the management of cerebral aneurysms continues to evolve and a purely endoscopic endonasal approach (EEA) for cerebral aneurysm has its own advantages. The purpose of the present study is to perform a detailed anatomical dissection study to test the usefulness of the extended EEAs for selected anterior communicating artery (ACoA) aneurysm.

Materials and Methods:

Nine human cadaveric heads were used for this study, and all dissections were performed through the endonasal corridor. Endoscopic endonasal surgical dissections were carried out, and surgery was simulated in all specimens to reach the ACoA region. The ACoA complex, its neural and osseous relations, degree of vascular exposure, and the ability to perform clip placement were observed and analyzed.

Results:

The transplanum and transtuberculum approaches exposed the A1 and A2 segments of the anterior cerebral artery and the ACoA in all specimens. This route allowed clip ligation of the distal A1 branches, ACoA and proximal A2 branches to the level of the pericallosal segment. Proximal and distal control was most readily achievable at the level of the ACoA complex.

Conclusion:

The present cadaveric study on nine specimens with bilateral dissection has demonstrated that the endonasal transplanum transtuberculum approach to the ACoA region provides excellent visualization of the vasculature. When selected prudently, such lesions may be favorable targets for an extended endoscopic endonasal (EEA) in comparison to transcranial approaches that may provide a suboptimal exposure.

Intraoperative Use of Endoscope, a Valuable, Adjunctive Tool for the Surgical Management of Anterior Communicating Artery Aneurysm Surgery: Our Institutional Experience

Background:

Anterior communicating (A-com) artery region is very complex; perforators are not always visualized on the microscope. The neuroendoscope with its higher magnification, better observation, and additional illumination can provide us information that may not be available with the microscope in aneurysm surgery.

Objective:

The objective was to study the use of endoscope in surgical management of A-com aneurysm surgery and its advantages, whether and how it changes operative management.

Materials and Methods:

We studied 25 serial cases of A-com aneurysm at Bantane Hospital, Fujita University, Japan, from November 2018 to October 2019. Once aneurysm was exposed, we did preclipping indocyanine green (ICG) study and examination with endoscope. After clipping, we again did ICG and endoscopic assessment. Preclipping and postclipping endoscopic information was used and necessary changes were made in the operative decisions. Whether endoscope gives any additional information over microscope and ICG which led to change in the operative decision was assessed.

Results:

In six out of 25 A-com aneurysm patients, the use of endoscope has given additional information over microscope, and ICG leading to change in the operative plans such as readjustment of the clip/application of the second clip or release of perforator compromise.

Conclusion:

Simultaneous endoscopic and microscopic guidance can reveal important information hidden from the microscope. Thus, this method increases the safety and durability of the A-com aneurismal clipping.

Anterior Temporal Approach and Clipping of a High-Riding Basilar Tip Aneurysm: Case Report and Review of the Surgical Technique

Basilar apex aneurysms constitute 5%–8% of all intracranial aneurysms. Microsurgical clipping of basilar tip aneurysms is still advocated for as it is safe, especially for unruptured basilar tip aneurysms which have a low risk of postoperative mortality or morbidity. Careful patient preparation is needed preoperatively because the risk of intraoperative rupture is significant. Good surgical techniques should be applied. The skill will need to be preserved as endovascular surgery becomes more popular. This is a case of basilar tip aneurysm managed by clipping through the anterior temporal approach, followed by a review of the literature.

Robotic oesophago-gastric cancer surgery

A postoperative complications rate of nearly 50% has compelled oesophago-gastric practice to adopt minimally invasive techniques such as robotic surgery

Robotics in neurosurgery

One of the first surgical specialties to adopt robotic procedures and one that continues to innovate

Fully Endoscope-Controlled Clipping Bilateral Middle Cerebral Artery Aneurysm Via Unilateral Supraorbital Keyhole Approach

Clipping bilateral middle cerebral artery (bMCA) aneurysms via unilateral approach in a single-stage operation is considered as a challenge procedure. To our knowledge, there is no study in surgical management of patients with bMCA aneurysms by fully endoscope-controlled techniques. The author reported a patient with bMCA aneurysms who underwent aneurysms clipping via a unilateral supraorbital keyhole approach by endoscope-controlled microneurosurgery, and the patient had an uneventful postoperative course without neurologic impairment and complication. Furthermore, the author discussed the advantages and adaptation of endoscope-controlled clipping bMCA aneurysms via unilateral supraorbital keyhole approach.

Keyhole Approach and Neuroendoscopy for Cerebral Aneurysms

Treating diseases in the field of neurosurgery has progressed concomitantly with technical advances. Here, as a surgical armamentarium for the treatment of cerebral aneurysms, the history and present status of the keyhole approach and the use of neuroendoscopy are reviewed, including our clinical data. The major significance of keyhole approach is to expose an essential space toward a target, and to minimize brain exposure and retraction. Among several kinds of keyhole approaches, representative keyhole approaches for anterior circulation aneurysms include superciliary and lateral supraorbital, frontolateral, mini-pterional and mini-interhemispheric approaches. Because only a fixed and limited approach angle toward a target is permitted via the keyhole, however, specialized surgical devices and preoperative planning are very important. Neuroendoscopy has helped to widen the indications of keyhole approaches because it can supply illumination and visualization of structures beyond the straight line of microscopic view. In addition, endoscopic indocyanine green fluorescence angiography is useful to detect and correct any compromise of the perforators and parent arteries, and incomplete clipping. The authors think that keyhole approach and neuroendoscopy are just an intermediate step and robotic neurosurgery would be realized in the near future.

The Clinical Importance of Perforator Preservation in Intracranial Aneurysm Surgery: An Overview with a Review of the Literature

Clipping for intracranial aneurysms is done to achieve complete occlusion of the aneurysm without a remnant sac. Despite modern advancements of neurosurgical techniques, morbidity related to the clipping of intracranial aneurysms still exists. Clip occlusion of a parent artery or small hidden perforators commonly leads to permanent neurological deficits, and is a serious and unwanted complication. Thus, preserving blood flow in the branches and perforators of a parent artery is very important for successful surgery without postoperative morbidity and mortality. The aim of this review article is to discuss the consequences of perforator injury and how to avoid this phenomenon in aneurysm surgeries using intraoperative monitoring devices.

Intraoperative Combined Use of Somatosensory Evoked Potential, Microvascular Doppler Sonography, and Indocyanine Green Angiography in Clipping of Intracranial Aneurysm

Background

The aim of this study was to evaluate the effect of combining application of somatosensory evoked potential (SEP), microvascular Doppler sonography (MDS), and indocyanine green angiography (ICGA) in intracranial aneurysm clipping surgery.

Material/Methods

A total of 158 patients undergoing an intracranial aneurysm clipping operation were recruited. All patients were evaluated with intraoperative SEP and MDS monitoring, and 28 of them were evaluated with intraoperative combined monitoring of SEP, MDS, and ICGA.

Results

The SEP waves dropped during temporary occlusion of arteries in 19 cases (12.0%), and returned to normal after the clips were repositioned. After aneurysms were clipped, the vortex flow signals were detected by MDS in 6 cases. The aneurysm neck remnants were detected by ICGA in 2 cases of olfactory artery (OA) and in 1 case of middle cerebral artery (MCA), which disappeared after the clips were repositioned. Postoperative CTA or DSA showed that aneurysms were clipped completely and parent arteries and perforating vessels were patent. GOS at 1 month after the surgery was good in 111 cases (70.3%), mild disability in 22 cases (13.9%), severe disability in 14 cases (8.9%), vegetative state in 5 cases (3.2%), and death in 6 cases (3.8%).

Conclusions

Intraoperative combining application of SEP, MDS, and ICGA can reduce brain tissue ischemia and damage and disability and mortality rate after effective clipping of intracranial aneurysms, thereby improving surgical outcomes.

Endoscopic Fluorescence Angiography with Indocyanine Green : A Preclinical Study in the Swine

OBJECTIVE

Microscopic indocyanine green (ICG) angiography is useful for identifying the completeness of aneurysm clipping and the preservation of parent arteries and small perforators. Neuroendoscopy is helpful for visualizing structures beyond the straight line of the microscopic view. We evaluated our prototype of endoscopic ICG fluorescence angiography in swine, which we developed in order to combine the merits of microscopic ICG angiography and endoscopy.

METHODS

Our endoscopic ICG system consists of a camera, a light source, a display and software. This system can simultaneously display real-time visible and near infrared fluorescence imaging on the same monitor. A commercially available endoscope was used, which was 4 mm in diameter and had an angle of 30°. A male crossbred swine was used.

RESULTS

Under general anesthesia, a small craniotomy was performed and the brain surface of the swine was exposed. ICG was injected via the ear vein with a bolus dose of 0.3 mg/kg. Visible and ICG fluorescence images of cortical vessels were simultaneously observed on the display monitor at high resolution. The real-time merging of the visible and fluorescent images corresponded well.

CONCLUSION

Simultaneous visible color and ICG fluorescent imaging of the cortical vessels in the swine brain was satisfactory. Technical improvement and clinical implication are expected.

Tendon-Driven Continuum Robot for Endoscopic Surgery: Preclinical Development and Validation of a Tension Propagation Model

In this paper, we present a tendon-driven continuum robot for endoscopic surgery. The robot has two sections for articulation actuated by tendon wires. By actuating the two sections independently, the robot can generate a variety of tip positions while maintaining the tip direction. This feature offers more flexibility in positioning the tip for large viewing angles of up to 180 degrees than does a conventional endoscope. To accurately estimate the tip position at large viewing angles, we employed kinematic mapping with a tension propagation model including friction between the tendon wires and the robot body. In a simulation study using this kinematic-mapping, the two-section robot at a target scale (outer diameter 1.7 mm and length 60 mm) produced a variety of tip positions within 50-mm ranges at the 180°-angle view. In the experimental validation, a 10:1 scale prototype performed three salient postures with different tip positions at the 180°-angle view. The proposed forward kinematic mapping (FKM) predicted the tip position within a tip-to-tip error of 6 mm over the 208-mm articulating length. The tip-to-tip error by FKM was significantly less than the one by conventional piecewise-constant-curvature approximation (PCCA) (FKM: 5.9 ± 2.9 mm vs. PCCA: 23.7 ± 3.6 mm, n=15, P < 0.01).

The Roles of Endoscope in Aneurysmal Surgery

The neuroendoscope, with its higher magnification, better observation, and additional illumination, can provide us information that may not be available with the microscope in aneurysm surgery. Furthermore, recent advancement of the holding systems for the endoscope allows surgeons to perform microsurgical manipulation using both hands under the simultaneous endoscopic and microscopic monitoring. With this procedure, surgeons can inspect hidden structures, dissect perforators at the back of the aneurysm, identify important vessel segments without retraction of the aneurysm or arteries, and check for completion of clipping. In addition, we have recently applied endoscopic indocyanine green video angiography to aneurysm surgery. This newly developed technique can offer real-time assessment of the blood flow of vasculatures in the dead angles of the microscope, and will reduce operative morbidity related to vascular occlusion, improve the durability of aneurysm surgery by reducing incomplete clipping, and thus promote the outcome of aneurysm surgery.

The endonasal approach for treatment of cerebral aneurysms: A critical review of the literature

The last two decades of neurosurgery have seen flourishing use of the endonasal approach for the treatment of skull base tumors. Safe and effective resections of neoplasms requiring intracranial arterial dissection have been performed using this technique. Recently, there have been a growing number of case reports describing the use of the endonasal approach to surgically clip cerebral aneurysms. We review the use of these approaches in intracranial aneurysm clipping and analyze its advantages, limitations, and consider future directions. Three major electronic databases were queried using relevant search terms. Pertinent case studies of unruptured and ruptured aneurysms were considered. Data from included studies were analyzed. 8 case studies describing 9 aneurysms (4 ruptured and 5 unruptured) treated by the endonasal approach met inclusion criteria. All studies note the ability to gain proximal and distal control and successful aneurysm obliteration was obtained for 8 of 9 aneurysms. 1 intraoperative rupture occurred and was controlled, and delayed complications of cerebrospinal fluid leak, vasospasm, and hydrocephalus occurred in 1, 1, and 2 patients, respectively. Described limitations of this technique include aneurysm orientation and location, the need for lower profile technology, and challenges with handling intraoperative rupture. The endonasal approach for clipping of intracranial aneurysms can be an effective approach in only very select cases as demonstrated clinically and through cadaveric exploration. Further investigation with lower profile clip technology and additional studies need to be performed. Options of alternative therapy, limitations of this approach, and team experience must first be considered.

Endoscope-assisted keyhole surgery via an eyebrow incision for removal of large meningiomas of the anterior and middle cranial fossa

BACKGROUND

Conventional open surgery of large meningiomas has proven to be challenging even in experienced hands. Intense retraction and dissection around neurovascular structures increase morbidity and mortality. In the present study, we retrospectively analyzed the surgical technique, and outcome in 40 patients with large anterior cranial fossa meningiomas extending to the middle fossa. All patients were approached via a supraorbital mini craniotomy.

METHODS

It is a retrospective study of 40 patients (12 males, 28 females) who underwent surgery for large anterior cranial fossa meningiomas (diameter >5 cm) extending to the middle fossa in four different neurosurgical centers within 6 years. Depending on the localization of the tumor, the skin incision was between 2.5 and 3 cm long and was made without shaving the patient's eyebrow hair. Subsequently, a keyhole craniotomy was performed of approximately 0.8×1.2-1.4 cm in diameter. Preoperative and postoperative clinical and radiological data were analyzed and discussed.

RESULTS

Headache and psycho-organic syndrome were the most common presenting symptom in all patients. Presenting symptoms were associated with psychological changes in 23 cases, visual impairment in 19 patients, and anosmia in 17 patients. In overall, 36 of 40 patients (90%) showed a good outcome and returned at long-term follow-up to their previous occupations. The elderly patients returned to their daily routine.

CONCLUSION

With the appropriate keyhole approach as a refinement of the classic keyhole craniotomy to a smaller key"burr"hole, and with use of modern and new designed equipment, it is possible to perform complete resection of large anterior and middle fossa meningiomas with the same safety, efficiency and with less complication rates as described in the literature for large meningiomas even performed with classic keyhole craniotomies.

Keyhole concept in cerebral aneurysm clipping and tumor removal by the supraciliary lateral supraorbital approach

The keyhole concept in neurosurgery is designed to minimize the craniotomy needed for the access route to deep intracranial pathologies. Such keyhole surgeries cause less trauma and can be less invasive than conventional surgical techniques. Among the various types of keyhole mini-craniotomy, supraorbital or lateral supraorbital mini-craniotomy is the standard and basic keyhole approaches. The lateral supraorbital keyhole provides adequate working space in the suprasellar to parasellar areas and planum sphenoidale area including the anterior communicating artery complex. Despite the development of neuro-endoscopic techniques and intra-operative assistant methods, the limited working angle to manipulate and observe deeply situated pathologies is a major disadvantage of the keyhole approaches. Neurosurgeons should understand that keyhole mini-craniotomy surgeries aim at “minimally invasive neurosurgery” but still carry the risks of malpractice unless we understand the advantages and disadvantages of these keyhole concepts and strategies.

Multi-section continuum robot for endoscopic surgical clipping of intracranial aneurysms

We propose the development and assessment of a multi-section continuum robot for endoscopic surgical clipping of intracranial aneurysms. The robot has two sections for bending actuated by tendon wires. By actuating the two sections independently, the robot can generate a variety of posture combinations by these sections while maintaining the tip angle. This feature offers more flexibility in positioning of the tip than a conventional endoscope for large viewing angles of up to 180 degrees. To estimate the flexible positioning of the tip, we developed kinematic mapping with friction in tendon wires. In a kinematic-mapping simulation, the two-section robot at the target scale (i.e., an outer diameter of 1.7 mm and a length of 60 mm) had a variety of tip positions within 50-mm ranges at the 180 degree-angled view. In the experimental validation, the 1:10 scale prototype performed the three salient postures with different tip positions at the 1800-angled view.

Endoscope-assisted microneurosurgery for intracranial aneurysms

Background: The endovascular techniques has widely changed the treatment of intracranial aneurysms. However surgery still represent the best therapeutic option in case of broad-based and complex lesions. The combined use of endoscopic and microsurgical techniques (EAM) may improve surgical results.

Objective: The purpose of our study is to evaluate the advantages and limits of EAM for intracranial aneurysms.

Methods: Between January 2002 and December 2012, 173 patients, harboring 206 aneurysms were surgically treated in our department with the EAM technique. One hundred and fifty-seven aneurysms were located in the anterior circulation and 49 were in the posterior circulation. Standard tailored approaches, based on skull base surgery principles, were chosen. The use of the endoscope included three steps: initial inspection, true operative time, and final inspection. For each procedure, an intraoperative video and an evaluation schedule were prepared, to report surgeons’ opinions about the technique itself. In the first cases, we always used the endoscope during surgical procedures in order to get an adequate surgical training. Afterwards we became aware in selecting cases in which to apply the endoscopy, as we started to become familiar with its advantages and limits.

Results: After clipping, all patients were undergone postoperative cerebral angiography. No surgical mortality related to EAM were observed. Complications directly related to endoscopic procedures were rare.

Conclusion: Our retrospective study suggests that endoscopic efficacy for aneurysms is only scarcely influenced by the preoperative clinical condition (Hunt–Hess grade), surgical timing, presence of blood in the cisterns (Fisher grade) and/or hydrocephalus. However the most important factors contributing to the efficacy of EAM are determined by the anatomical locations and sizes of the lesions. Furthermore, the advantages are especially evident using dedicated scopes and holders, after an adequate surgical training to increase the learning curve.

Endoscope-integrated ICG technology: first application during intracranial aneurysm surgery

Microscopic indocyanine green videoangiography (mICG-VA) has gained wide acceptance during intracranial aneurysm surgery by lowering rates of incomplete clipping and occlusion of surrounding vessels. However, mICG-VA images are limited to the microscopic view and some deeper areas, including the aneurysm sac/neck posterior side, cannot be efficiently assessed as they are hidden by the aneurysm, clips, or surrounding structures. Contrarily, endoscopes allow a wider area of visualization, but neurosurgical endoscopes to date only provided visual data. We describe the first application of endoscope ICG-integrated technology (eICG) applied in an initial case of anterior communicating artery aneurysm clipping. This new technique provided also relevant information regarding aneurysm occlusion and patency of parent and branching vessels and small perforating arteries. eICG-VA provided additional information compared to mICG-VA by magnifying areas of interest and improving the ability to view less accessible regions, especially posterior to the aneurysm clip. Obtaining eICG sequences required currently the microscope to be moved away from the operating field. eICG-VA was only recorded under infrared illumination which prevented tissue handling, but white-infrared light views could be interchanged instantaneously. Further development of angled endoscopes integrating the ICG technology and dedicated filters blocking the microscopic light could improve visualization capacities even further. In conclusion, as a result of its ability to reveal structures around corners, the eICG-VA technology could be beneficial when used in combination with mICG-VA to visualize and confirm vessel patency in areas that were previously hidden from the microscope.