3D exoscopic versus microscopic superficial temporal artery to middle cerebral artery bypass surgery for moyamoya disease - a comparative series

PURPOSE

Superficial temporal artery to middle cerebral artery (STA-MCA) direct bypass surgery is the most common surgical procedure to treat moyamoya disease (MMD). Here, we aim to compare the performance of the 3D exoscope in bypass surgery with the gold standard operative microscope.

METHODS

All direct STA-MCA bypass procedures performed at a single university hospital for MMD between 2015 and 2023 were considered for inclusion. Data were retrospectively collected from patient files and surgical video material. From 2020 onwards, bypass procedures were exclusively performed using a digital three-dimensional exoscope as visualization device. Results were compared with a microsurgical bypass control group (2015-2019). The primary endpoint was defined as total duration of surgery, duration of completing the vascular anastomosis (ischemia time), bypass patency, number of stiches to perform the anastomosis, added stiches after leakage testing of the anastomosis and the Glasgow outcome scale (GOS) at last follow-up as secondary outcome parameter.

RESULTS

A total of 16 consecutive moyamoya patients underwent 21 STA-MCA bypass procedures. Thereof, six patients were operated using a microscope and ten patients using an exoscope (ORBEYE® n = 1; AEOS® n = 9). Total duration of surgery was comparable between devices (microscope: 313 min. ± 116 vs. exoscope: 279 min. ± 42; p = 0.647). Ischemia time also proved similar between groups (microscope: 43 min. ± 19 vs. exoscope: 41 min. ± 7; p = 0.701). No differences were noted in bypass patency rates. The number of stiches per anastomosis was similar between visualization devices (microscope: 17 ± 4 vs. exoscope: 17 ± 2; p = 0.887). In contrast, more additional stiches were needed in microscopic anastomoses after leakage testing the bypass (p = 0.035).

CONCLUSION

Taking into account the small sample size, end-to-side bypass surgery for moyamoya disease using a foot switch-operated 3D exoscope was not associated with more complications and led to comparable clinical and radiological results as microscopic bypass surgery.

Cataract surgery using two 3D visualization systems: Complication rates, surgical duration & comparison with traditional microscopes

PURPOSE

To compare the complication rates and surgical duration of cataract surgery using two 3D visualization systems and a traditional binocular microscope among experienced and inexperienced surgeons.

METHODS

This retrospective case series included 571 eyes that received cataract surgery using either heads up cataract surgery, via a 3D head mounted system (N = 148-Group 1) or a 3D display screen (N = 338 eyes-Group 2), or traditional binocular microscope (N = 85 eyes-Group 3). The surgical records of consecutive patients who underwent cataract surgery by two groups of surgeons (experienced and inexperienced) were reviewed. Patients in all groups received either femtosecond laser assisted cataract surgery (FLACS) or traditional phacoemulsification. Complication rate, as well as duration of cataract surgery were evaluated between all three visualization approaches, between experienced and inexperienced surgeons.

RESULTS

There was no statistically significant difference in duration of surgery between all 3 visualization approaches for both experienced and inexperienced surgeons (p < 0.05). Furthermore, the type of surgical technique (manual or FLACS) did not affect the surgical duration for both experienced and inexperienced surgeons (p < 0.05). No intraoperative complications were demonstrated in the current cohort.

CONCLUSIONS

The implementation of heads up-3D visualization either through a screen or a head mounted platform for cataract surgery seems to offer similar safety and efficiency as the traditional binocular microscope, and both experienced and inexperienced surgeons demonstrate the same outcomes in terms of safety and efficiency.

Functionality and Usability of the Exoscope in Microvascular Decompression for Hemifacial Spasm and Trigeminal Neuralgia

BACKGROUND

Studies on the functionality and usability of the exoscope in neurosurgical procedures against surgical microscopes (SMs) are limited. This study aimed to examine the functionality and usability of the exoscope during microvascular decompression (MVD) surgery.

METHODS

Seven neurosurgeons evaluated the usefulness of a 4 K, 3-dimension digital exoscope in MVD by answering a questionnaire. The questionnaire inquired about the functionality and usability of the exoscope by utilizing a visual analog scale (VAS; 1-10). A score of 5 on VAS was equivalent to the corresponding quality of the SM. The learning effect of the exoscope was evaluated using mean VAS scores in the first and last 3 cases for each neurosurgeon.

RESULTS

The functionality of the exoscope in MVD was superior to that in SM (P < 0.001). In the last 3 surgeries, the mean VAS scores of the exoscope were excellent in terms of ease of arm handling, exchange of surgical instruments, ease of surgical procedure, and intraoperative physical stress. The mean VAS scores of the exoscope in intraoperative asthenopia were significantly higher than those of the SM (P < 0.001). No statistical significance was found in operation time, discharge outcome, and 1-year post-surgery outcome between MVD performed using the exoscope and SM.

CONCLUSIONS

Neurosurgeons may experience reduced stress levels during MVD when using the exoscope. As the outcome of MVD using the exoscope did not demonstrate a statistical difference compared with MVD using the SM, the exoscope may prove to be a useful tool for performing MVD.

Evaluating the exoscope as an alternative to the operating microscope in plastic surgery

BACKGROUND

Microsurgery is most commonly used in the anastomosis of vessels, flap harvesting, lymphedema, and nerve reconstruction, among others. During the 1920s the first microscope was invented by Nylen and Holmgren, quickly becoming the gold standard for microsurgery. However, technological advances have come forth in the form of exoscopes.

METHODS

A search for full-text articles where using an exoscope was compared with a traditional operating microscope was conducted on the databases PubMed, Scopus, Web of Science, and Embase. The following terms were used to guide our search: Microscope AND exoscope AND plastic surgery; Microscope AND exoscope AND microvascular surgery.

RESULTS

Our search yielded 69 studies, of which 12 were included. Five exoscope systems were used by the authors. All studies reported the exoscope as a valid alternative to the standard operating microscope. The exoscope was reported as non-inferior to the operating microscope. Although some studies reported lower quality of image, this did not seem to influence the outcome of surgeries. Newer models may have bridged the gap between the operating microscope's image quality and the exoscope. Superior ergonomics was always reported among the included studies.

CONCLUSION

Based on our search, we conclude that the exoscope is a safe and valid alternative to the operating microscope in plastic surgery. As newer models are now commercially available, these have overcome difficulties in image quality and zoom capabilities, responsible for the main drawbacks of the first exoscope systems.

Musculoskeletal demands in microsurgery-an explorative study comparing the ergonomics of microscope and 3D exoscope

To assess neurosurgeons' physical demands and investigate ergonomic aspects when using microsurgical visualization devices. Six neurosurgeons performed micro-surgical procedures on cadaveric specimens using the prototype of a digital 3D exoscope system (Aeos®, Aesculap, Tuttlingen, Germany) and a standard operating microscope (Pentero 900, Zeiss, Oberkochen, Germany) at two different patient positions (semisitting (SS), supine (SP)). The activities of the bilateral upper trapezius (UTM), anterior deltoid (ADM), and lumbar erector spinae (LEM) muscles were recorded using bipolar surface electromyography and neck flexion, arm abduction, and arm anteversion angles by gravimetrical posture sensors. Perceived discomfort frequency was assessed and subjects compared the two systems in terms of usability, posture, physical and mental demands, and working precision. Using the exoscope led to reduced ADM activity and increased UTM and LEM activity during SS position. The neck was extended when using the exoscope system with lower arm anteversion and abduction angles during the SS position. Subjects reported discomfort at the shoulder-neck area less frequently and lower physical demands when using the Aeos®. However, mental demands were slightly higher and two subjects reported lower working precision. The exoscope system has the potential to reduce the activity of the ADM by changing surgeons arm posture which may be accompanied by less discomfort in the shoulder-neck area. However, dependent on the applied patient position higher muscle activities could occur in the UTM and LEM.

Surgical resection of glioblastoma in basal ganglia and utility of exoscope: Technical case reports

Background

Due to the presence of many perforating arteries and the deep location of basal ganglia tumors, dissection of the perforating arteries is critical during tumor resection. However, this is challenging as these arteries are deeply embedded in the cerebrum. Surgeons need to bend their heads for a long time using operative microscope and it is uncomfortable for the operating surgeon. A high-definition (4K-HD) 3D exoscope system can significantly improve the surgeon's posture during resection and widen the operating view field considerably by adjusting the camera angle.

Methods

We report two cases of glioblastoma (GBM) involving basal ganglia. We used a 4K-HD 3D exoscope system for resecting the tumor and analyzed the intraoperative visualization of the operative fields.

Results

We could approach the deeply located feeding arteries before successfully resecting the tumor using a 4K-HD 3D exoscope system which would have been difficult with the sole use of an operative microscope. The postoperative recoveries were uneventful in both cases. However, postoperative magnetic resonance imaging showed infarction around the caudate head and corona radiata in one of the cases.

Conclusion

This study has highlighted using a 4K-HD 3D exoscope system in dissecting GBM involving basal ganglia. Although postoperative infarction is a risk, we could successfully visualize and dissect the tumors with minimal neurological deficits.

Neurovascular Microsurgical Experience Through 3-Dimensional Exoscopy: Case Report and Literature Review

BACKGROUND

The microscope is important in neurosurgery, but it is not exempt from limitations. The exoscope has emerged as an alternative because it offers better 3-dimensional (3D) visualization and better ergonomics. We present our initial experience in vascular pathology using 3D exoscopy at the Dos de Mayo National Hospital to show the viability of the 3D exoscope in vascular microsurgery. We also provide a review of the literature.

METHODS

In this work, the Kinevo 900 exoscope was used in 3 patients with cerebral (2) and spinal (1) vascular pathology. We evaluated the image quality, equipment management, ergonomics, educational utility, and 3D glasses and recorded the characteristics of the cases. We reviewed the experience of other authors as well.

RESULTS

Three patients underwent surgery: 1 occipital cavernoma, 1 cerebral dural fistula, and 1 spinal dural fistula. Excellent 3D visualization with Zeiss Kinevo 900 exoscope (Carl Zeiss, Germany), surgical comfort, and educational utility occurred, and there were no complications.

CONCLUSIONS

Our experience and that of other authors suggests that the 3D exoscope shows excellent visualization, better ergonomics, and an innovative educational experience. Vascular microsurgery can be performed safely and effectively.

Beyond Magnification and Illumination: Ergonomics with a 3D Exoscope in Lumbar Spine Microsurgery to Reduce Musculoskeletal Injuries

OBJECTIVE

The risk of musculoskeletal injuries (MSIs) increases over years of practice which may lead to career-ending among surgeons. Exoscopes represent a new generation of imaging systems that help surgeons operate in a more comfortable posture. This article aimed to assess advantages and limitations, especially ergonomics with a 3D exoscope in lumbar spine microsurgery versus an operating microscope (OM) to reduce MSIs.

METHODS

From March 2018 to May 2020, 90 patients with lumbar disc herniation undergoing a single-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) procedure were included. Forty-seven patients were operated with the assistance of the exoscope and 43 patients were operated with the assistance of the OM. Clinical data, magnification, and illumination were evaluated. In particular, the ergonomics of surgeons was evaluated by a questionnaire (subjective) and a rapid entire body assessment (REBA; objective).

RESULTS

The postoperative outcomes were reasonably well balanced between the two groups. The handling of the exoscope was comparable to that of the OM. The depth perception, image quality, and illumination of the exoscope were inferior to those of the OM in MIS-TLIF with long and deep approaches. The educational and training function of the exoscope was superior to that of the OM. Importantly, surgeons rated the ergonomics of the exoscope as very high on the questionnaire and the REBA to the OM (P = 0.017).

CONCLUSIONS

This study showed that the exoscope was a safe and effective alternative to the OM for assisting the MIS-TLIF procedure with the unique advantage of ergonomics to reduce musculoskeletal injuries.

Exoscope and operative microscope for training in microneurosurgery: A laboratory investigation on a model of cranial approach

Objective

To evaluate the viability of exoscopes in the context of neurosurgical education and compare the use of a 4k3D exoscope to a traditional operative microscope in the execution of a task of anatomic structure identification on a model of cranial approach.

Material and methods

A cohort of volunteer residents performed a task of anatomical structure identification with both devices three times across an experimental period of 2 months. We timed the residents’ performances, and the times achieved were analyzed. The volunteers answered two questionnaires concerning their opinions of the two devices.

Results

Across tries, execution speed improved for the whole cohort. When using the exoscopes, residents were quicker to identify a single anatomical structure starting from outside the surgical field when deep structures were included in the pool. In all other settings, the two devices did not differ in a statistically significant manner. The volunteers described the exoscope as superior to the microscope in all the aspects the questionnaires inquired about, besides the depth of field perception, which was felt to be better with the microscope. Volunteers furthermore showed overwhelming support for training on different devices and with models of surgical approaches.

Conclusion

The exoscope appeared to be non-inferior to the microscope in the execution of a task of timed identification of anatomical structures on a model of cranial approach carried out by our cohort of residents. In the questionnaires, the residents reported the exoscope to be superior to the microscope in eight of nine investigated domains. Further studies are needed to investigate the use of the exoscope in learning of microsurgical skills.

3D Exoscopes in Experimental Microanastomosis: A Comparison of Different Systems

Background: In recent years, three-dimensional exoscopes have been increasingly applied in neurosurgery. Multiple exoscopic systems are available, all offering specific features. In this study, we assessed practical and visualization performance of four different exoscopic systems in a highly challenging microsurgical procedure, and evaluated whether these affected the quality of work. Methods: We included four different exoscopes: Olympus ORBEYE, Zeiss KINEVO, Storz VITOM, and Aesculap AEOS. With each exoscope, ten experimental bypass procedures were carried out on chicken wing vessels at a depth of 3 cm. We evaluated the quality of the anastomoses, the practical considerations for the setup of the exoscopic systems, and the visualization quality by tracking the number of unnecessary movements. Results: All included exoscopes enabled us to perform the bypass procedures with mostly adequate or excellent results. Surgically, the most pronounced difference between the exoscopes was the duration of the procedure, which was mainly due to the number of unnecessary movements. Practically, the exoscopes differ highly which is important when considering which exoscope to apply. Conclusions: This is the first study comparing different exoscope systems while performing the same challenging microsurgical procedure. We found major practical differences between the exoscopes that determine the suitability of an exoscope based on the demands and conditions of the surgical procedure. Therefore, preprocedural practical training with the exoscope is required.

3D Exoscopes are Noninferior to Operating Microscopes in Aneurysm Surgery: Comparative Single-Surgeon Series of 52 Consecutive Cases

OBJECTIVE

The literature on exoscope use in cerebrovascular neurosurgery is scarce, mainly comprising small case series and focused on visualization quality and ergonomics. As these devices become widely used, direct comparison to the operating microscope regarding efficacy and patient safety is necessary.

METHODS

Fifty-two consecutive clipping procedures, performed by 1 senior vascular neurosurgeon, were analyzed. Either an operating microscope with a mouth switch (25 cases with 27 aneurysms; 13 ruptured) or a three-dimensional exoscope with a foot switch (27 cases with 34 aneurysms; 6 ruptured) were used. Durations of major surgical stages, number of device adjustments, numbers of clip repositionings and clips implanted were extracted from surgical videos. Demographic data, imaging characteristics, clinical course and outcomes were extracted from digital patient records.

RESULTS

Duration of surgery and different stages did not differ between devices, except for final site inspection. The number of device adjustments was higher with the exoscope. With progressive experience in exoscope use, the number of device adjustments increased significantly, whereas surgery duration remained unchanged. Favorable outcome (modified Rankin Scale score 0-2) was observed in 80% and 88% of patients in the microscope and exoscope groups, respectively. Ischemic events were found in 2 patients in each group; no other complications occurred.

CONCLUSIONS

In aneurysm clipping, three-dimensional exoscopes are noninferior to operating microscopes in terms of surgery duration, safety, and outcomes, based on our limited series. Progressive experience enables the surgeon to perform significantly more device adjustments within the same amount of surgical time.

Efficacy of a High-definition Three-dimensional Exoscope in Simultaneous Transcranial and Endoscopic Endonasal Surgery: A Case Report

Owing to recent advances in medical optical technology, a high-definition (4K) three-dimensional (3D) exoscope has been developed as an alternative tool to using conventional microscopes for microscopic surgery, and its efficacy for neurosurgery has been reported. We report a case who underwent simultaneous surgery aiming for en bloc resection of an anterior skull base malignancy with concurrent exoscopic transcranial and endoscopic endonasal approaches using a 4K 3D exoscope. The patient was a 76-year-old woman who underwent en bloc resection for an anterior skull base olfactory neuroblastoma 13 years ago. After confirming the recurrence of progressive olfactory neuroblastoma, tumor resection was again decided to be performed. As with the first procedure, surgery was performed in an en bloc manner, using both transcranial and endonasal approaches. Exoscope provided enough space above the surgical field to allow us to perform transcranial and endonasal surgeries simultaneously. Moreover, the surgeons could maintain a comfortable posture throughout the procedure, and total tumor removal was successfully achieved without any abnormal event. To our knowledge, this is the first report of the introduction of an exoscope aiming for en bloc resection of an anterior skull base malignancy while performing simultaneous surgery with both transcranial and endonasal approaches. We believe that the more cases are accumulated, the more efficacy of a 4K 3D exoscope will be elucidated.

Microvascular anastomosis in a challenging setting using a 4 K three-dimensional exoscope compared with a conventional microscope: An in vivo animal study

BACKGROUND

Three-dimensional (3D) exoscope systems have been developed and are reported to be adequate alternatives to the conventional microscope. This study aimed to evaluate the feasibility and effectivity of microvascular anastomosis using a 4 K 3D exoscope in an in vivo animal study.

METHODS

The abdominal aortas of mice were selected as the target vessels for comparing the outcomes of microvascular anastomosis for both the conventional microscope and 3D exoscope. We recorded the vessel separation, temporary occlusion, and total procedure durations. Local conditions at the sutures were also recorded. Typical histopathological images were presented, and the patency of anastomotic vessels within 5 and 30 min were evaluated. All procedures included both superficial and deep anastomosis.

RESULTS

Sixty mice were included in the analysis; the weight and vascular diameter were 38.5 ± 5.8 g and 0.77 ± 0.06 mm, respectively, and around 8 stiches were required. Regarding feasibility, vessel separation duration, temporary occlusion duration, total procedure duration, blood leak, and number of vascular folds between stiches, the results were comparable between the two types of microscopes. The feasibility of anastomosis was also confirmed by pathology. Regarding effectiveness, anastomotic vascular patency at 5 and 30 min were similar for both microscopes. Even in the more difficult scenario of deep anastomosis, the results were comparable.

CONCLUSIONS

In a challenging experimental setting, comparable outcomes of microvascular anastomosis were observed for the conventional microscope and 3D exoscope in these animal experiments. Therefore, in vivo microvascular anastomosis is feasible and effective using a 3D exoscope.

Exoscope as a Teaching Tool: A Narrative Review of the Literature

Recently, the emergence of the three-dimensional (3D) exoscope has proven to be a viable alternative to the operative microscope (OM) as a novel workhorse of microneurosurgical procedures. Through its current iteration, the 3D exoscope has been demonstrated to be at least equivalent to the operative microscope in terms of surgical outcomes in many settings. With its superior ergonomics and simplicity of use, the 3D exoscope has been shown in multiple studies to be a powerful visualizing tool during surgical procedures. Moreover, the exoscopic systems, through their current iterations and by means of a high-resolution 3D monitor and 3D glasses, have allowed all participants present in the operative room to attain an unprecedented level of intraoperative visualization of anatomical structures and surgical maneuvers which are traditionally available only to the first operator. Although long-term data are still lacking regarding its future as a replacement of the OM, the 3D exoscope has revealed itself as an intense subject of discussion in neurosurgery regarding its implication for surgical education, especially for residents and junior neurosurgeons. This article is a review of the current state of the literature on the role of the exoscope in surgical education, underlining its strength as a learning tool and its potential future implications in terms of surgical education.

Lateral Supracerebellar Infratentorial Approach for Superior Oblique Myokymia: A Case Series

BACKGROUND

Few reports have shown that superior oblique myokymia (SOM) may result from vascular compression of the trochlear nerve and may be curable using microvascular decompression (MVD).

OBJECTIVE

To report the clinical characteristics and surgical treatment of 2 cases of SOM and provide a review of the related literature.

METHODS

Two patients with SOM were treated using MVD with the lateral supracerebellar infratentorial approach. The patients underwent diagnostic magnetic resonance imaging and three-dimensional fusion imaging preoperatively. A lateral suboccipital craniotomy was performed in the park-bench position. The trochlear nerve and branches of the superior cerebellar artery were confirmed after opening the cerebellomesencephalic fissure over the tentorial surface of the cerebellum. The vessel, which compressed the root exit zone of the trochlear nerve, was transposed far from the nerve and attached to the surface of the midbrain using Teflon felt and fibrin glue.

RESULTS

The first case showed compression on both the ventral and rostral sides of the trochlear nerve root exit zone, and the second showed compression only on the ventral side. Large bridging veins on the tentorial surface of the cerebellum complicated the approach in the second case. Postoperatively, both patients had immediate and complete resolution of symptoms without recurrence at the 24-mo and 17-mo follow-ups, respectively. Five previous reports described the complete resolution of SOM after MVD.

CONCLUSION

A presentation of an intermittent fluttering ocular sensation should prompt magnetic resonance imaging for ipsilateral trochlear nerve compression. The lateral supracerebellar infratentorial approach allows safe and efficacious MVD for SOM.

Exoscope for Upper Extremity Peripheral Nerve Surgery: Revision Carpal Tunnel Release With Epineurolysis and Hypothenar Fat Flap

The exoscope is a high-resolution three-dimensional external microscope that allows the surgeon to perform delicate dissection in multiple regions of the body. The exoscope was originally used for intracranial and spine surgery. In this article, we describe its novel use in upper extremity peripheral nerve decompression surgery after recurrent carpal tunnel syndrome. This surgery is typically performed under the microscope, which allows precise microsurgical dissection to distinguish scar tissue from healthy nerve fascicles. Our case report highlights a 70-year-old man with recurrent carpal tunnel syndrome who underwent revision carpal tunnel surgery with epineurolysis and hypothenar fat flap. The ergonomic benefits of using the exoscope for microsurgery are described, along with intraoperative photos. Adequate symptom resolution was achieved.

Evaluation of 3D Robotic-Guided Exoscopic Visualization in Microneurosurgery

Objective

The three-dimensional (3D) exoscope is a novel apparatus introduced in recent years. Although an operating microscope (OM) is customarily used, this novel application offers several advantages. Therefore, this study aimed to determine the feasibility of deploying a robotic-guided 3D-exoscope for microneurosurgery and gauge its subsequent performance.

Methods

The use of a 3D exoscope was compared with that of OM during 16 surgical procedures. Postoperatively, surgeons completed an eight-item Likert-scale satisfaction survey. As a second step, a predefined surgical task was then undertaken by surgeons with varying levels of experience, assessing the time entailed. Two questionnaires, the satisfaction survey and NASA task load index (NASA-TLX), were administered.

Results

During routine procedures, the exoscope proved superior in magnification and ergonomic maintenance, showing inferior image contrast, quality, and illumination. It again ranked higher in magnification and ergonomic maintenance during the suturing task, and the OM excelled in treatment satisfaction and stereoscopic orientation. Workload assessment using the NASA-TLX revealed no difference by modality in the pairwise analysis of all components. At varying levels of experience, beginners bear a significantly higher burden in all principle components than mid-level and expert participants (p = 0.0018). Completion times for the suturing task did not differ (p = 0.22).

Conclusion

The quality of visualization by 3D exoscope seems adequate for treatment and its ergonomic benefit is superior to that of OM. Although experienced surgeons performed a surgical simulation faster under the OM, no difference was evident in NASA-TLX surveys. The 3D exoscope is an excellent alternative to the OM.

The Exoscope in Neurosurgery: An Overview of the Current Literature of Intraoperative Use in Brain and Spine Surgery

Background: Exoscopes are a safe and effective alternative or adjunct to the existing binocular surgical microscope for brain tumor, skull base surgery, aneurysm clipping and both cervical and lumbar complex spine surgery that probably will open a new era in the field of new tools and techniques in neurosurgery. Methods: A Pubmed and Ovid EMBASE search was performed to identify papers that include surgical experiences with the exoscope in neurosurgery. PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses) were followed. Results: A total of 86 articles and 1711 cases were included and analyzed in this review. Among 86 papers included in this review 74 (86%) were published in the last 5 years. Out of 1711 surgical procedures, 1534 (89.6%) were performed in the operative room, whereas 177 (10.9%) were performed in the laboratory on cadavers. In more detail, 1251 (72.7%) were reported as brain surgeries, whereas 274 (16%) and 9 (0.5%) were reported as spine and peripheral nerve surgeries, respectively. Considering only the clinical series (40 studies and 1328 patients), the overall surgical complication rate was 2.6% during the use of the exoscope. These patients experienced complication profiles similar to those that underwent the same treatments with the OM. The overall switch incidence rate from exoscope to OM during surgery was 5.8%. Conclusions: The exoscope seems to be a safe alternative compared to an operative microscope for the most common brain and spinal procedures, with several advantages that have been reached, such as an easier simplicity of use and a better 3D vision and magnification of the surgical field. Moreover, it offers the opportunity of better interaction with other members of the surgical staff. All these points set the first step for subsequent and short-term changes in the field of neurosurgery and offer new educational possibilities for young neurosurgery and medical students.

Exoscopic carotid endarterectomy using movable 4K 3D monitor: Technical note

Background:

Carotid endarterectomy (CEA) using conventional surgical microscope has been already established as golden standard. Recently, exoscope was introduced into the field of neurosurgery, and various merits of it have been reported. We report the experiences of exoscopic CEA using a movable 4K 3D monitor and discuss the feasibility of it.

Methods:

We report a consecutive series of 15 cases of exoscopic CEA for internal carotid artery (ICA) stenosis using a movable 4K 3D monitor between January 2020 and April 2021. We utilized ORBEYE as an exoscope system and a 31-inch movable 4K 3D monitor, which was installed in the Maquet Moduevo ceiling supply unit.

Results:

In all 15 cases, the procedures were accomplished only using the ORBEYE. There were no operative complications due to the use of the exoscope. In response to the operative site, the 4K 3D monitor was moved to face the operator. Even when the angle of the visual axis of the exoscope against the horizontal plane was small during the surgical manipulation in the distal portion of ICA, the operator was able to maintain a comfortable posture.

Conclusion:

Using the movable 4K 3D monitor, exoscopic CEA can be performed ergonomically. The operator can manipulate the distal portion of the ICA or proximal portion of the common carotid artery in a comfortable posture and face the monitor by adjusting its position.

The Utility of High-Definition 2-Dimensional Stereotactic Exoscope in Cranial and Spinal Procedures

BACKGROUND

The use of an exoscope in neurosurgical procedures has been proposed to improve ergonomics and to overcome the limitations faced with the microscope and endoscope. However, there remains scarcity of data regarding its surgical utility and outcomes.

OBJECTIVES

The authors report their experience and evaluate the surgical outcomes using a high-definition 2-dimensional (HD-2D) stereotactic exoscope in the management of various cranial and spinal pathologies.

METHODS

We retrospectively identified patients who underwent neurosurgical procedures using the HD-2D stereotactic exoscope over a 2-year period. Demographic and surgical characteristics were analyzed.

RESULTS

Twenty-nine patients (70.7%) underwent cranial surgery, and 12 patients (29.3%) underwent spine surgery. In patients having brain tumor removal, gross total resection was achieved in 18 patients (62.1%); with an overall average pathology size of 4.2±1.6 cm. Adjuvant utilization of the microscope was required in 4 cranial cases (13.8%) to ensure optimal resection rate. Three complications and 2 mortalities were encountered in the cranial group during a mean follow-up of 4.6±3.3 months. In the spinal cohort, the HD-2D stereotactic exoscope was utilized for anterior decompression and fusion (n=5), posterior decompression and fusion (n=5), and microdiscectomy and foraminotomy (n=2). No complications were encountered in the spinal group during a mean follow-up of 3.8±2.7 months.

CONCLUSION

The HD-2D stereotactic exoscope offers a wider field of view, greater mean focal distance, enhanced ergonomics, and immersive stereotactic visual experience. The lack of stereopsis remains the principal limitation of its use, and further optimization of surgical outcomes might be achieved with newer 3D models.

Four Hands Surgery for Intracerebral Hemorrhage using Orbeye: Educational Values and Ergonomic Advantages - A Technical Note

We have developed a new educational approach to microsurgery in which a trainee and supervisor can cooperate with “4 hands” using the exoscope. We evaluated 4-hands surgery for intracranial hemorrhage (ICH) using the exoscope to validate the educational value and ergonomic advantages of this method. Thirty consecutive patients who underwent surgery for ICH using the exoscope between December 2018 and May 2020 were studied retrospectively. All operations were performed by a team comprising a supervisor (assistant) and a trainee (main operator). The assistant set the visual axis of the exoscope, and adjusted focus and magnification as a scopist. After setting the ORBEYE, the supervisor helped retract the brain and withdraw and irrigate the hematoma using suction tubes or brain retractors. Moreover, the trainee evacuated the hematoma with a suction tube and coagulated using bipolar forceps. Patient background and results of treatment were evaluated. Intraoperative postures of the operators were observed, and schemas compared with the use of a conventional microscope were developed. All microsurgical procedures were accomplished by a trainee with a supervisor using only the exoscope. During the surgery, the surgeons could work in a comfortable posture, and the supervisor and trainee could cooperate in microsurgical procedures using their four hands. The results of the present case series concerning evacuation of ICH were not inferior to those described in previous reports. To increase opportunities for education in microsurgery, 4-hands surgery for ICH using the exoscope appears feasible and safe and offered excellent educational value and ergonomic advantages.

Technical aspects and operative nuances using a high-definition 4K-3-dimensional exoscope for carotid endarterectomy surgery

PURPOSE

Carotid endarterectomy (CEA) is effective in treating carotid artery stenosis to prevent stroke. Historically, this operation has been performed utilizing loupe magnification with or without the operating microscope (OM). However, there remains a need for continued improvement in operative visualization and surgical ergonomics. Recently, newly developed digital 'exoscope' has provided the surgeon with unique lighting and magnification as well as improvements in surgical ergonomics and working angle. We sought to review our cumulative experience using a novel 4K high-definition (4K-HD) 3-dimensional (3D) exoscope (EX) for CEA surgery.

METHODS

All CEA surgery cases at our institution between 2013 and 2019 using the 4K-HD 3D EX were reviewed. Operative parameters, patient outcome and operator's assessment of the EX compared to OM-assisted cases was conducted.

RESULTS

28 patients were treated, 10 of which were operated using the EX. All procedures were performed without perioperative complications, or significant differences in operative parameters (blood loss <20 cm3 and 164 ± 49.5 minutes) compared to OM-assisted cases. Operators reported improved level of comfort performing 'high' bifurcation surgery and improved visualization and posture during inspection of the distal ICA lumen as primary advantages of EX-assisted CEA over OM-assisted CEA.

CONCLUSIONS

The ORBEYE EX, albeit a learning curve necessitating a short period of the OR team, provided safety and outcome comparable to OM-assisted surgery. Potential advantages noted were improved visualization and ergonomics specifically for when extreme working angles were required. Our experience suggests that the exoscope may become a valuable alternative to standard magnification tools in CEA surgery.

Evaluation of a Novel Three-Dimensional Robotic Digital Microscope (Aeos) in Neurosurgery

OBJECTIVE

Current literature debates the role of newly developed three-dimensional (3D) Exoscopes in the daily routine of neurosurgical practice. So far, only a small number of cadaver lab studies or case reports have examined the novel Aesculap Aeos Three-Dimensional Robotic Digital Microscope. This study aims to evaluate the grade of satisfaction and intraoperative handling of this novel system in neurosurgery.

METHODS

Nineteen neurosurgical procedures (12 cranial, 6 spinal and 1 peripheral nerve) performed over 9 weeks using the Aeos were analyzed. Ten neurosurgeons of varying levels of training were included after undergoing device instruction and training. Following every surgery, a questionnaire consisting of 43 items concerning intraoperative handling was completed. The questionnaires were analyzed using descriptive statistics.

RESULTS

No intraoperative complications occurred. Surgical satisfaction was ranked high (78.95%). In total, 84.21% evaluated surgical ergonomics as satisfactory, while 78.95% of the surgeons would like to use this system frequently. Image quality, independent working zoom function and depth of field were perceived as suboptimal by several neurosurgeons.

CONCLUSION

The use of Aeos is feasible and safe in microsurgical procedures, and surgical satisfaction was ranked high among most neurosurgeons in our study. The system might offer advanced ergonomic conditions in comparison to conventional ocular-based microscopes.

Beyond magnification and illumination: preliminary clinical experience with the 4K 3D ORBEYE™ exoscope and a literature review

BACKGROUND

The operating microscope (OM) is an invaluable tool in neurosurgery but is not without its flaws. The ORBEYE™ (Olympus, Tokyo, Japan) is a 4K 3D exoscope aspiring to offer similar visual fidelity but with superior ergonomics. 2D visualisation was a major limitation of previous models which newer 3D exoscopes attempt to overcome. Here, we present our initial experience using a 4K 3D exoscope for neurosurgical procedures.

OBJECTIVE

To evaluate the feasibility of the ORBEYE™ exoscope in performing neurosurgery and review of the literature.

METHODS

All patients undergoing neurosurgery performed by a single surgeon, using the ORBEYE™, were assessed. Descriptive statistics and data relating to complications and operative time were recorded and analysed. An anecdotal literature review was performed for the experience of other authors using 4K 3D exoscopes in neurosurgery and compared to our subjective experience with the ORBEYE™.

RESULTS

18 patients underwent surgery using the ORBEYE™. There were no 30-day post-operative complications observed. Our experience and that of other authors suggests that the ORBEYE™ offers comparable visualisation to the traditional OM, with superior ergonomics and an enhanced experience for assistants and observers.

CONCLUSION

Neurosurgery can be performed safely and effectively with the ORBEYE™, with improved ergonomics and educational benefit. There appears to be a short learning curve provided one has experience with endoscopic surgery and the use of a foot pedal.

4K 3-dimensional video microscope system (orbeye) for transsphenoidal pituitary surgery

Background

In previous reports on experiences with an exoscope, this new technology was not found to be applicable for transsphenoidal pituitary surgery. As a specialized center for pituitary surgery, we were using a 4K 3D video microscope (Orbeye, Olympus) to evaluate the system for its use in transsphenoidal pituitary surgery in comparison to conventional microscopy.

Method

We report on 296 cases performed with the Orbeye at a single institution. An observational study was conducted with standardized subjective evaluation by the surgeons after each procedure. An objective measurement was added to compare the exoscopic and microscopic methods, involving surgery time and the initial postoperative remission rate in matched cohorts.

Results

The patients presented with a wide range of pathologies. No serious events or minor complications occurred based on the usage of the 4K 3D exoscope. There was no need for switching back to the microscope in any of the cases. Compared to our microsurgically operated collective, there was no significant difference regarding duration of surgery, complications, or extent of resection. The surgeons rated the Orbeye beneficial in regard to instrument size, positioning, surgeon’s ergonomics, learning curve, image resolution, and high magnification.

Conclusions

The Orbeye exoscope presents with optical and digital zoom options as well as a 4K image resolution and 3D visualization resulting in better depth perception and flexibility in comparison to the microscope. Split screen mode offers the complementary benefit of the endoscope which may increase the possibilities of lateral view but has to be evaluated in comparison to endoscopic transsphenoidal procedures in the next step.

High-Definition 4K 3D Exoscope (ORBEYETM) in Peripheral Nerve Sheath Tumor Surgery: A Preliminary, Explorative, Pilot Study

BACKGROUND

Surgery for peripheral nerve sheath tumors aims to preserve functional fascicles achieving gross-total resection. Increasing the visualization of anatomic details helps to identify the different layers and the tumor-nerve interface. The traditional microscope can present some limitations in this type of surgery, such as its physical obstruction.

OBJECTIVE

To present a proof-of-concept study about exoscope-guided surgery for schwannomas of the lower limbs, to analyze the advantages and disadvantages of the 4K, high-quality, 3-dimensional (3D) imaging.

METHODS

We analyzed 2 consecutive surgical cases of suspected schwannomas of the lower limbs using the ORBEYE™ exoscope (Olympus). A standard operative microscope was also available in the operating room. All procedures were performed with neurophysiological monitoring, to identify functioning nerves and to localize the tumor capsule safest entry point. The cases are reported according to the PROCESS guidelines.

RESULTS

In both cases, we achieved a gross total resection of the schwannomas; the exoscope provided an excellent view of the anatomic details at tumor-nerve interface, as visible in intraoperative images and in the 3D-4K video supporting these findings. The surgeon's position was comfortable in both cases, although if the co-surgeon positioned himself in front of the first surgeon, the comfort was slightly reduced. The 4K monitor allowed a realistic, nontiring 3D vision for all the team.

CONCLUSION

The ORBEYETM, after an adequate learning curve, can represent a feasible and comfortable instrument for nerve tumor surgery, which is usually performed in a single horizontal plane. Further and wider clinical series are necessary to confirm this first impression.

Clinical implementation of a 3D4K-exoscope (Orbeye) in microneurosurgery

Exoscopic surgery promises alleviation of physical strain, improved intraoperative visualization and facilitation of the clinical workflow. In this prospective observational study, we investigate the clinical usability of a novel 3D4K-exoscope in routine neurosurgical interventions. Questionnaires on the use of the exoscope were carried out. Exemplary cases were additionally video-documented. All participating neurosurgeons (n = 10) received initial device training. Changing to a conventional microscope was possible at all times. A linear mixed model was used to analyse the impact of time on the switchover rate. For further analysis, we dichotomized the surgeons in a frequent (n = 1) and an infrequent (n = 9) user group. A one-sample Wilcoxon signed rank test was used to evaluate, if the number of surgeries differed between the two groups. Thirty-nine operations were included. No intraoperative complications occurred. In 69.2% of the procedures, the surgeon switched to the conventional microscope. While during the first half of the study the conversion rate was 90%, it decreased to 52.6% in the second half (p = 0.003). The number of interventions between the frequent and the infrequent user group differed significantly (p = 0.007). Main reasons for switching to ocular-based surgery were impaired hand–eye coordination and poor depth perception. The exoscope investigated in this study can be easily integrated in established neurosurgical workflows. Surgical ergonomics improved compared to standard microsurgical setups. Excellent image quality and precise control of the camera added to overall user satisfaction. For experienced surgeons, the incentive to switch from ocular-based to exoscopic surgery greatly varies.

A Single-Center Experience with the Olympus ORBEYE 4K-3D Exoscope for Microsurgery of Complex Cranial Cases: Technical Nuances and Learning Curve

BACKGROUND

 The introduction of exoscopes in neurosurgery has been welcomed due to their maneuverability, ergonomics, and low-profile frame. 3D devices have further enabled a better stereoscopic visualization. Reports on their application, albeit more and more frequent, are still at their beginning stages. We present our experience with the Olympus ORBEYE 4K-3D exoscope for major cranial procedures. The strengths and weaknesses of the exoscope are presented, and the nuances associated with the learning curve are illustrated.

METHODS

 Over 2 weeks, patients undergoing surgery for major cranial pathologies were offered to participate in this evaluation of the Olympus ORBEYE 4K-3D exoscope. Information on the use of the exoscope was collected to assess the features and struggles in the learning curve. A comparison with the operating microscope was made.

RESULTS

 Fourteen patients with different intracranial pathologies were operated on with the exoscope. No surgery-related complications occurred. The microsurgical part was performed with the exoscope in six cases. The exoscope was used for 72.9% (±37.5%) of the whole microsurgical time vs. 27.1% (±37.5%) microscope time (p = 0.02).

CONCLUSION

 The Olympus ORBEYE 4K-3D exoscope represents a useful evolution of the operating microscope. It requires time to overcome potential difficulties, mostly related to previous motor schemes acquired with operating microscopes. Its features could represent the basis for a paradigm shift in microsurgery.

Comparison of Operating Microscope and Exoscope in a Highly Challenging Experimental Setting

BACKGROUND

The use of a digital three-dimensional (3D) exoscope system in neurosurgery is increasing as an alternative to the operative microscope. The objective of this study was to compare a digital 3D exoscope system with a standard operating microscope as a neurosurgical visualization tool in a highly challenging experimental setting.

METHODS

End-to-side bypass procedures, each at a depth of 9 cm, were performed in a simulation setting. The quality of the task and the depth effect, visualization, magnification, illumination, and ergonomics were evaluated.

RESULTS

No major differences were noted between the microscope and the 3D exoscope in terms of the quality of the work. Working with the 3D exoscope was more time-consuming than working with the microscope. Changing the depth and focus was faster using the operative microscope. The 3D exoscope enabled higher magnification and offered better ergonomic features.

CONCLUSIONS

In a highly challenging experimental setting, comparable procedural quality was found for the microscope and the 3D exoscope. Each visualization tool had advantages and disadvantages. Over time and with technologic advances, the digital 3D exoscope may become the main operative visualization system in microneurosurgery.

3D-exoscopic visualization using the VITOM-3D in cranial and spinal neurosurgery. What are the limitations?

OBJECTIVE

3D exoscopic visualization in neurosurgical procedures is of interest for several reasons. The VITOM-3D exoscopic system is cheaper compared to the operating microscope (OM) and offers each person involved in the procedure the same image of the operative field. Little is known of limitations of this visualization technique.

PATIENTS AND METHODS

Prospectively, a consecutive series 34 procedures were assessed with focus on the following aspects: intraoperative limitation and the cause for a switch to the OM or endoscopy. A standardized questionnaire was answered by each individual involved in the procedure to assess the image quality, illumination, and magnification of the operative field. Intraoperative video recording and pre- and postoperative MRI and CT-scan were analyzed to assess the dimensions of the surgical approach.

RESULTS

Sixteen cranial and 18 spinal procedures (10 intra-axial, 6 extra-axial, 6 cervical, and 12 lumbar) were performed by seven neurosurgical attendings, twelve residents and twelve scrub nurses who all completed a standardized questionnaire after each procedure. Handling and identification of anatomical structures was rated equal or superior to the OM in 62 % and over 80 % of cases, respectively. The illumination and magnification of the operative field on the surface was rate in equal od superior in all cases and on the depth it was rated inferior to the OM over 60 % of cases. In one spinal and five cranial procedures a switch to the OM or endoscope were performed for the following reasons: poor illumination (4 cases), tissue identification (1 case), need for fluorescence imaging (1 case).

CONCLUSION

3D exoscopic visualization using the VITOM-3D is best suited for spinal procedures and for extra-axial cranial procedures. In case of small approach dimensions, the illumination and magnification of the depth of the operative field is rated inferior to the OM which resulted in difficulty of tissue identification and a switch to the OM.

Use of a compact high-definition two-dimensional exoscope in surgical treatment of large vestibular schwannoma

Background:

Extra-corporeal video telescope operating monitor system provides a necessary instrument to perform high-precision neurosurgical procedures that could substitute or supplement the traditional surgical microscope. The present study was designed to evaluate a compact high-definition two-dimensional exoscope system for assisting in surgical removal of large vestibular schwannoma (VS), as an alternative to a binocular surgical microscope.

Methods:

Patients with Koos grade 3 and grade 4 VS undergoing surgery were enrolled in this prospective cohort study between January 2013 and June 2018. The demographics and tumor characteristics (size, Koos grade, composition [cystic or solid mass]) were matched between the two groups of patients. The following outcome measurements were compared between the two groups: duration of surgery, volume of blood loss, extent of tumor resection, number of operating field adjustments, pre- and post-operative facial and cochlear nerve function evaluated at 3 months post-surgery, complications and surgeons’ comfortability.

Results:

A total of 81 patients received tumor resection through the retrosigmoid approach under either an exoscope (cases, n = 39) or a surgical microscope (control, n = 42). Patients in the two groups had comparable tumor location (P = 0.439), Koos grading (P = 0.867), and composition (P = 0.891). While no significant differences in the duration of surgery (P = 0.172), extent of tumor resection (P = 0.858), facial function (P = 0.838), and hearing ability (P = 1.000), patients operated on under an exoscope had less blood loss (P = 0.036) and a fewer field adjustments (P < 0.001). Both primary and assistant surgeons reported a high level of comfort operating under the exoscope (P = 0.001 and P < 0.001, respectively).

Conclusions:

The compact high-definition two-dimensional exoscope system provides a safe and efficient means to assist in removing large VSs, as compared to a surgical microscope. After the acquaintance with a visual perception through a dynamic hint and stereoscopically viewing corresponding to the motion parallax, the exoscope system provided a comfortable, high-resolution visualization without compromising operational efficiency and patient safety.

Microsurgery "Under the Eaves" Using ORBEYE: A Case of Dural Arteriovenous Fistula of the Anterior Cranial Fossa

BACKGROUND

One of the merits of exoscopes, including ORBEYE, is that they are superior to a microscope in terms of ergonomic features. We report a case of dural arteriovenous fistula (dAVF) that was cured by direct surgery using the ergonomic advantages of ORBEYE.

CASE DESCRIPTION

A 78-year-old man was found to have dAVF of the anterior cranial fossa incidentally. We performed direct surgery via bifrontal craniotomy. Because the frontal sinus was large, we reserved the frontal bone-like eaves in order not to open the frontal sinus. The vertex of his head was sufficiently down to shift the frontal lobe downward with gravity. During surgery, we set the angle of the operative visual axis of ORBEYE approximately horizontal to avoid the reserved frontal bone. We performed a stable operation using ORBEYE in a comfortable posture.

CONCLUSIONS

ORBEYE facilitates ergonomic microsurgery, even under the eaves, with the angle of the operative visual axis approximately horizontal using gravity.

Comparison of Conventional Microscopic and Exoscopic Experimental Bypass Anastomosis: A Technical Analysis

BACKGROUND

Recently, the use of digital exoscopes has been increasingly promoted as an alternative to microscopes. The aim of this study is to compare experimental bypass quality in both visualization methods.

METHODS

This study used two hundred 1-mm chicken wing vessels, which were used for either exoscopic or microscopic (100 samples each) bypass procedures. All procedures were recorded between July 2018 and September 2018. The bypass quality was evaluated according to our published practical scale (time, stitch distribution, intima-intima attachment, and orifice size).

RESULTS

Both methods are effective in doing bypass suturing (practical scale score was good, 86% vs. 85%; P = 0.84). There were no significant differences regarding intima-intima attachment (P = 0.26) and orifice size (P = 0.25). However, suturing time (P < 0.001) was less using the microscope, whereas stitch distribution (P = 0.001) was better using the exoscope. Different suturing techniques (interrupted vs. continuous) had overall comparable results (P = 0.55).

CONCLUSIONS

Both methods produced equally satisfactory results in experimental bypass procedures. The exoscope has the potential for better 3-dimensional visualization and sharing the surgeon's view with others for teaching purposes.

Heads-up Cataract Surgery: Complication Rates, Surgical Duration, and Comparison With Traditional Microscopes

PURPOSE

To compare the complication rates and surgical duration between a three-dimensional visualization system (heads-up surgery) and traditional binocular microscope in cataract surgery.

METHODS

This retrospective case series included 2,320 eyes that received cataract surgery using either a three-dimensional display system (n = 1,673 eyes) (3D group) or a traditional binocular microscope (n = 647 eyes) (traditional group). The medical records of consecutive patients who underwent cataract surgery by a single surgeon in The Eye Institute of West Florida from August 2016 to July 2017 using either a three-dimensional display system or the traditional binocular microscope for visualization were reviewed. Patients in both groups received either femto-second laser-assisted cataract surgery (FLACS) or traditional phacoemulsification. Complication rate (posterior capsular rapture and vitreous prolapse) and duration of cataract surgery were evaluated.

RESULTS

The 3D group had 12 (0.72%) complications and the traditional group had 5 (0.77%) complications (P > .05). Mean surgical time was 6.48 ± 1.15 minutes for the 3D group and 6.52 ± 1.38 minutes for the traditional group (P > .05). There was no statistically significant difference in complication rate and duration of surgery between the two groups (P > .05).

CONCLUSIONS

The implementation of heads-up three-dimensional visualization for cataract surgery seems to offer similar safety and efficiency as the traditional binocular microscope. [J Refract Surg. 2019;35(5):318-322.].