A Novel Three-Dimensional Robot Arm Steered Camera for Ear Surgery

ABSTRACT

Ear surgery requires magnified imaging of anatomical structures from its beginning to achieve safe and successful surgical outcomes. The historical evolution of magnification in otology has developed from monocular to binocular, and to three-dimensional and even to digital in modern times. Current technological advancements pursue high-quality visualization for the best surgical outcomes but also ergonomic for surgeons. Here, we evaluated the usability of such new technology in common otological surgeries like cochlear implantation and stapedectomy for the first time in patients. A three-dimensional camera mounted to a robot arm has hands-free control by goggles worn by the surgeon on a head mount. The camera at a distance of the patients but can also be draped in a sterile way that it forms a barrier tent between patient and surgical personnel in the theatre. The main reason to evaluate the feasibility of this new exoscope was driven by COVID-19 obligate measures for elective surgery such as hearing restoration. This new technology can be considered an important advantage for the surgeons working in microsurgery to perform their elective operations without aerosolization of the drill rinsing water possibly containing contaminated tissue. From a subjective point of view, the image quality is equivalent to conventional microscopes to provide safe otologic surgery.

Case Report: High-Definition 4K-3D Exoscope for Removal of an Orbital Cavernous Hemangioma Using a Transpalpebral Approach

Background: Cavernous hemangioma, also known as cavernous vascular malformation (CVM), is the most common primary lesion of the orbit in adults. The management of these lesions is challenging and is strongly dependent on their location, as well as the patient's symptoms and expectations. The trans-palpebral approach is currently used in surgery for orbital tumors, anterior skull base tumors, and even more, orbital reconstruction, because of its well-demonstrated esthetic advantages. Similarly, the use of magnification can be provided by surgical loupes, microscope, or more recently, endoscope, which is well-documented for its advantages in terms of minimal invasiveness and safety. In the last years, the use of exoscopes in microsurgery has been proposed due to their greater and sharper intraoperative magnification, but never for the removal of orbital tumors. Clinical Presentation: We describe a case of a 38-year-old woman with a right orbital intraconic CVM removed using an inferior transpalpebral approach performed under 4K-3-dimensional (4K-3D) exoscopic vision. Navigation and ultrasound were also used, with the former allowing better identification of the lesion within the orbit and the second overcoming the limitations of navigation, in terms of the retraction on the ocular globe before or just after periorbital incision. Conclusion: The use of a 4K-3D exoscope allowed us to perform the surgery safely, thanks to the high magnification and definition of anatomical details, with the surgeon operating in an upright, comfortable position. The CVM was completely removed with excellent results from both functional and esthetic points of view.

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.

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.

High-Definition 3-Dimensional Exoscope for 5-ALA Glioma Surgery: 3-Dimensional Operative Video

A 54-yr-old man presented with the radiological recurrence of a glioblastoma at the level of the left anterior cingulate gyrus, 46 mo after first surgery, which had been complicated by bone flap infection. Due to the relatively small recurrence, the long survival, and the good neurological status, surgery was warranted. A new, high-definition (4 K) and 3-dimensional exoscope (ORBEYE; Sony Olympus Medical Solutions Inc, Tokyo, Japan) was used during the surgical approach and throughout tumor removal, which was aided by five-aminolevulinic acid (5-ALA) derived fluorescence. The postoperative course was characterized by supplementary motor area syndrome, which quickly improved, leading to a discharge home 1 wk after surgery. Histological examination confirmed a wild-type (WT) IDH1/2, MGMT (DNA repair enzyme O6-methylguanine-DNA methyltransferase) methylated glioblastoma with a proliferative index focally as high as 20%. He is now being considered for a second-line treatment. As recently reported for spinal surgery,1 we believe this technology has significant potential for its small dimension (which can provide optimal positioning even in ergonomically challenging positions), ease of movement, and image quality, including 5-ALA fluorescence. The patient's consent was obtained for publication.

Advances in Intraoperative Optics: A Brief Review of Current Exoscope Platforms

BACKGROUND

The advent of the operating microscope (OM) revolutionized the field of neurosurgery. It allowed surgeons to operate on and effectively treat diseases previously inaccessible with conventional eyesight because of magnification and illumination. Improvements in the essential methods of visualization and the quality of the optics have plateaued. Another main limitation of the OM remains its ergonomics because of the need of the surgeon and assistant to directly interface with the OM objective. Recently, exoscopes have been introduced to overcome some shortcomings of the conventional OM.

OBJECTIVE

To subjectively review the individual authors experience with the current exoscope platforms in an attempt to provide a resource to the neurosurgeon when considering imaging options.

METHODS

Experts with previous use of each individual platform were contacted and asked to contribute their experiences.

RESULTS

In total, 4 systems are discussed. They include the VITOM (Karl Storz, Tuttlingen, Germany), the Olympus ORBEYE (Olympus, Tokyo, Japan), the Synaptive Modus V (Synaptive Medical, Toronto, Canada), and the Zeiss KINEVO (Carl Zeiss AG, Oberkochen, Germany).

CONCLUSION

The advent of exoscopes has the potential to begin to allow surgeons to move beyond solely the microscope for intraoperative visualization while improving upon its ergonomic disadvantages.

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.

The Role of 3D Exoscope Systems in Neurosurgery: An Optical Innovation

The development of the three-dimensional (3D) exoscope is a marvel of technological innovation in modern surgical practice. While its predecessor, the operating microscope (OM), has long been the gold-standard surgical visualization modality, its particular limitations in terms of accessibility and ergonomic demand have led to the development of a more sophisticated, 3D model. Specifically, the 3D exoscope allows for an enhanced image quality of the surgical field, while also being more ergonomically favorable. Moreover, this device's ability to handle delicate microsensitve procedures, along with its alleviation of surgeon fatigue, indicates great potential for neurosurgical application. For this narrative review, the authors queried PubMed database using the keyword "exoscope" to identify relevant studies involving the specialty of neurosurgery that were published in English language full text. The search yielded full-text English language-related articles regarding neurosurgical exoscope, its applications and limitations. The 3D exoscope uniquely allows for enhanced surgeon comfort and superior imaging of the patient's real-time anatomy. However, the OM was described to having a slight image favorability with fusion and decompression surgery. Cost analysis is highlighted for its potential disparity. 3D exoscopes will potentially be incorporated with intelligent carriers and robotic surgical systems. Ultimately, with further studies highlighting its use, the 3D exoscope is expected to continue to imprint its status as one of the most efficient technological visualization tools in the future of neurosurgical practice.

Resection of Intracranial Tumors with a Robotic-Assisted Digital Microscope: A Preliminary Experience with Robotic Scope

BACKGROUND

Magnified intraoperative visualization is of paramount importance during microsurgical procedures. Although the introduction of the operating microscope represented one of the most relevant innovations in modern neurosurgery, surgical vision and maneuverability can be limited in cases with unfavorable angles of attack. In such cases, the placement of the operating microscope can be difficult and result in significant discomfort to the surgeon. In previous decades, exoscopes were introduced as alternative tools to provide optimal ergonomics by decoupling the line of sight of the surgeon from the binocular lenses. However, exoscopic platforms entail interim manual adjustments of the camera position and setting. To overcome this limitation, robotic-assisted digital microscopy was developed. We have reported our preliminary experience with the RoboticScope to investigate the feasibility and safety of this novel digital system for intraoperative magnification.

METHODS

In September 2020, the RoboticScope was used to perform 3 cranial procedures for the resection of brain tumors. The surgeon's opinion was recorded to evaluate the quality of the intraoperative vision, the safety and efficacy of the surgical maneuverability, and the surgeon's personal comfort.

RESULTS

RoboticScope provided remarkable advantages in terms of enhanced workflow efficacy and increased comfort of the surgeon during the microsurgical phase of the cranial procedures. The overall quality of the intraoperative digital imaging was rated not inferior to that of traditional optical microscopes.

CONCLUSIONS

The RoboticScope is a promising device that might represent a valuable alternative to conventional tools for intraoperative visualization in the resection of intracranial tumors.

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.

Mechanism and design of a novel 8K ultra-high-definition video microscope for microsurgery

The practical application of microscopes using 8K ultra-high definition (UHD) technology is progressing. However, due to insufficiencies in factors such as luminous intensity and stereopsis, it has not been possible to achieve sufficient image quality for close observation of submillimeter order microlymphatic anastomosis using a combination of 8K-UHD cameras with a rigid endoscope. We have improved the quality of microsurgery by the introduction of a new heads up 8K-UHD surgical system. Herein, we show the mechanisms of this next-generation technology that makes optical improvements to the electronic image input data, resolving the initial drawback.

We have developed a new 8K-UHD digital microscope system with digital zooming to enable maximum 300X magnification of the surgical field. This system has specific lighting settings for shadows dropped in surgical field to expand the three-dimensional effect while still being a monocular camera. The original mechanism and design enable the increase of the depth of field with optimal angles between the imaging direction and approaching direction towards the surgical field.

Assessment during a pre-clinical trial using rats demonstrated that it is possible to perform microlymphatic anastomosis in a heads-up position with a 70-inch 8K-UHD monitor and the 8K-UHD monocular camera system.

Performing supermicrosurgery is difficult with conventional surgical microscopes. Our results illustrate the application of this new 8K-UHD microscope system to this new field.

Transoral laser microsurgery: feasibility of a new exoscopic HD-3D system coupled with free beam or fiber laser

In the last decades, new technological devices and instruments have been developed to overcome the technical limits of transoral laser microsurgery. The recent introduction of 3D endoscopy seems to be a promising tool in the field of diagnostic and operative laryngology as an alternative to the traditional microlaryngoscopy. Our work aims to present a novel transoral microsurgical setting that expands the use of exoscopic systems (in this case the VITOM® 3D-HD) as an alternative to the standard operating microscope. A customized support arm and an adaptor to firmly connect the VITOM® 3D-HD camera to the laser micromanipulator were specially designed. This setup was used as an alternative to the standard operating microscope in a cohort of 17 patients affected by suspicious early to intermediate pharyngo-laryngeal neoplasms. A historical cohort of patients treated with the traditional setting and matching the same inclusion criteria was used as a reference for the duration of surgical procedures. The surgical procedures comprised 7 cordectomies, 2 endoscopic partial supraglottic laryngectomies, 4 tongue base resections, and 4 lateral oropharyngectomies or hypopharyngectomies. In 6 cases (35%), a simultaneous neck dissection was performed. The low rate of positive deep (6%) or superficial (12%) margins reinforced the safety of this platform, and the results obtained in terms of operating time were comparable to the control group (p > 0.05), which confirms the feasibility of the system. Our surgical setting setup is a convincing alternative to traditional transoral laser microsurgery for early to intermediate pharyngo-laryngeal neoplasms. The main advantages of this system are comfortable ergonomics for the first surgeon and a potential benefit in terms of teaching if applied in university hospitals, since the entire surgical team can view the same surgical 3D-HD view of the first operator. Further work is still needed to objectively compare the traditional and new technique, and to validate our preliminary clinical findings.

Introducing the High-definition 3D exoscope in ear surgery: preliminary analysis of advantages and limits compared with operative microscope

PURPOSE

The aim of this study was to evaluate the potential of 3D exoscope (EX) in selected ear procedures assessing if this new technology could be an improvement in the field of ear surgery.

METHODS

A case series of consecutive patients surgically treated with a post-auricular approach using EX was retrospectively compared with a similar previous series treated with operating microscope (OM). Patient demographics, indications for surgery, procedure type, complications, operating room setting time (ORst), operative time, adequacy of visualization, image quality, ergonomics aspects, instrument usability, and technique as a teaching tool were investigated. Thirteen patients were included in each group. Surgical procedures in EX group were nine tympanoplasties with mastoidectomy, 1 mastoidectomy for acute complicated mastoiditis, 1 revision miringoplasty, and 2 cochlear implants. Same types of procedures were enrolled in OM group.

RESULTS

No statistically significant difference was found between the two groups concerning ORst and operative time. In EX group, one complication occurred--a middle cranial fossa cerebrospinal fluid leak. Advantages of EX were lightness, maneuverability and compactness, less need of endoscopy during surgery, and teaching potential. Limits were a need of a large surgical corridor and the bright structures rendering in high magnification.

CONCLUSION

EX resulted safe and efficient in treating diseases of the middle ear in post-auricular approaches. To date, EX advantages are not enough to abandon the OM, and it can be considered as an additional, innovative tool to be added to ear surgical equipment.

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.

Monitor-based exoscopic 3D4k neurosurgical interventions: a two-phase prospective-randomized clinical evaluation of a novel hybrid device

Background

Promoting a disruptive innovation in microsurgery, exoscopes promise alleviation of physical strain and improved image quality through digital visualization during microneurosurgical interventions. This study investigates the impact of a novel 3D4k hybrid exoscope (i.e., combining digital and optical visualization) on surgical performance and team workflow in preclinical and clinical neurosurgical settings.

Methods

A pre-clinical workshop setting has been developed to assess usability and implementability through skill-based scenarios (neurosurgical participants n = 12). An intraoperative exploration in head and spine surgery (n = 9) and a randomized clinical study comparing ocular and monitor mode in supratentorial brain tumor cases (n = 20) followed within 12 months. Setup, procedure, case characteristics, surgical performance, and user experience have been analyzed for both ocular group (OG) and monitor group (MG).

Results

Brain tumor cases using frontal, frontoparietal, or temporal approaches have been identified as favorable use cases for introducing exoscopic neurosurgery. Mean monitor distance and angle were 180 cm and 10°. Surgical ergonomics when sitting improved significantly in MG compared with OG (P = .03). Hand-eye coordination required familiarization in MG. Preclinical data showed a positive correlation between lateral camera inclination and impact on hand-eye coordination (r_s = 0.756, P = .01). There was no significant added surgical time in MG. Image quality in current generation 3D4k monitors has been rated inferior to optic visualization yet awaits updates.

Conclusions

The hybrid exoscopic device can be integrated into established neurosurgical workflows. Currently, exoscopic interventions seem most suited for cranial tumor surgery in lesions that are not deep-seated. Ergonomics improve in monitor mode compared to conventional microsurgery.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04361-2) contains supplementary material, which is available to authorized users.

A high-definition 3D exoscope as an alternative to the operating microscope in spinal microsurgery

OBJECTIVE

Since the 1970s, the operating microscope (OM) has been a standard for visualization and illumination of the surgical field in spinal microsurgery. However, due to its limitations (e.g., size, costliness, and the limited movability of the binocular lenses, in addition to discomfort experienced by surgeons due to the posture required), there are efforts to replace the OM with exoscopic video telescopes. The authors evaluated the feasibility of a new 3D exoscope as an alternative to the OM in spine surgeries.

METHODS

Patients with degenerative pathologies scheduled for single-level lumbar or cervical spinal surgery with use of a high-definition 3D exoscope were enrolled in a prospective cohort study between January 2019 and September 2019. Age-, sex-, body mass index-, and procedure-matched patients surgically treated with the assistance of the OM served as the control group. Operative baseline and postoperative outcome parameters were assessed. Periprocedural handling, visualization, and illumination by the exoscope, as well as surgeons' comfort level in terms of posture, were scored using a questionnaire.

RESULTS

A 3D exoscope was used in 40 patients undergoing lumbar posterior decompression (LPD) and 20 patients undergoing anterior cervical discectomy and fusion (ACDF); an equal number of controls in whom an OM was used were studied. Compared with controls, there were no significant differences for mean operative time (ACDF: 132 vs 116 minutes; LPD: 112 vs 113 minutes) and blood loss (ACDF: 97 vs 93 ml; LPD: 109 vs 55 ml) as well as postoperative improvement of symptoms (ACDF/Neck Disability Index: p = 0.43; LPD/Oswestry Disability Index: p = 0.76). No intraoperative complications occurred in either group. According to the attending surgeon, the intraoperative handling of instruments was rated to be comparable to that of the OM, while the comfort level of the surgeon's posture intraoperatively (especially during "undercutting" procedures) was rated as superior. In cases of ACDF procedures and long approaches, depth perception, image quality, and illumination were rated as inferior when compared with the OM. By contrast, for operating room nursing staff participating in 3D exoscope procedures, the visualization of intraoperative process flow and surgical situs was rated to be superior to the OM, especially for ACDF procedures.

CONCLUSIONS

A 3D exoscope seems to be a safe alternative for common spinal procedures with the unique advantage of excellent comfort for the surgical team, but the drawback is the still slightly inferior visualization/illumination quality compared with the OM.

First-in-Man Clinical Experience Using a High-Definition 3-Dimensional Exoscope System for Microneurosurgery

BACKGROUND

During its development and preclinical assessment, a novel, 3-dimensional (3D), high-definition (4K-HD) exoscope system was formerly shown to provide an immersive surgical experience, while maintaining a portable, low-profile design.

OBJECTIVE

To assess the clinical applicability of this 3D 4K-HD exoscope via first-in-man surgical use.

METHODS

The operative workflow, functionality, and visual haptics of the 3D 4K-HD exoscope were assessed in a variety of microneurosurgical cases at 2 US centers.

RESULTS

Nineteen microneurosurgical procedures in 18 patients were performed exclusively using the 3D 4K-HD exoscope. Pathologies treated included 4 aneurysms, 3 cavernous malformations (1 with intraoperative electrocorticography), 2 arteriovenous malformations, 1 foramen magnum meningioma, 1 convexity meningioma, 1 glioma, 1 occipital cyst, 1 chiari malformation, 1 carotid endarterectomy, 1 subdural hematoma, 1 anterior cervical discectomy and fusion, and 2 lumbar laminectomies. All patients experienced good surgical and clinical outcomes. Similar to preclinical assessments, the 3D 4K-HD exoscope provided an immersive 3D surgical experience for the primary surgeon, assistants, and trainees. The small exoscope frame, large depth of field, and hand/foot pedal controls improved exoscope mobility, decreased need to re-focus, and provided unobstructed operative corridors. Flexible positioning of the camera allows the surgeon's posture to be kept in a neutral position with uncompromised viewing angles.

CONCLUSION

The first-in-man clinical experience with the 3D 4K-HD exoscope confirms its excellent optics and ergonomics for the entire operative team, with high workflow adaptability for a variety of microneurosurgical cases. Expanded clinical use of the 3D 4K-HD exoscope is justified.

Minimally Invasive Navigated Foraminal Discectomy via Contralateral Approach Using a 3-Dimensional 4K High-Definition Exoscope: 2-Dimensional Operative Video

This surgical video is the first to demonstrate a novel minimally invasive technique of utilization of surgically navigated foraminal discectomy using a 3-dimensional 4k high-definition exoscope (Sony Olympus). Typical approaches for foraminal disc herniations may involve violation of the facet resulting in subsequent destabilization requiring fusion.1 Although minimally invasive facet-sparing contralateral techniques have previously been described,2 there is continued limitations stemming from rudimentary localization with standard fluoroscopy and impaired visualization with the bulky traditional operative microscope.3 We demonstrate that high-quality real-time navigation is possible using standard Iso-C intraoperative fluoroscopy for 3-dimensional reconstructions, allowing for intraoperative routing. Navigation is particularly advantageous for adjustments in the trajectory of the tubular retractor and for confirmation of complete foraminal decompression. Visualization from the 4k high-definition exoscope also allows for an unparalleled view of the narrow operative corridor and allows for participation from the operative team. Informed consent was obtained from the patient for the surgery in its entirety.

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.

Recent Technical Advancements of Endoscopic Spine Surgery with Disparate or Disruptive Technologies and Patents

There have been numerous technical advancements in the field of endoscopic spine surgery since it began in the 1980s and its use further expanded in the 1990s. At present, there are many newer technical advancements in this field, each trying to expand the indications and afford more accurate execution of this procedure. We predict some technologies which can be classified as being disruptive and have the potential of being game changers in this exciting field in the near future.

Utility of a high-definition 3D digital exoscope for spinal surgery during the COVID-19 pandemic

The COVID-19 pandemic creates unique challenges in the practice of spinal surgery. We aim to show how the use of a high-definition 3D digital exoscope can help streamline workflows, and protect both patients and healthcare staff.

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.

Imaging Technologies in Spine Surgery

This article presents a comprehensive review of the evolution of both invasive and noninvasive imaging technologies that are part of the arsenal of spinal diagnostics and surgical therapy. The text provides not only a historical lens to the evolution of the imaging technologies that are part of routine contemporary practice but also provides a detailed sketch of emerging imaging technologies, such as endoscopic and exoscopic systems. Augmented reality, virtual reality, and mixed reality are new technologies that have enhanced the preparation of surgery and provide excellent case-specific training modules to break down each step of an operation in isolation.

Spine Surgery Supported by Augmented Reality

STUDY DESIGN

A prospective, case-based, observational study.

OBJECTIVES

To investigate how microscope-based augmented reality (AR) support can be utilized in various types of spine surgery.

METHODS

In 42 spinal procedures (12 intra- and 8 extradural tumors, 7 other intradural lesions, 11 degenerative cases, 2 infections, and 2 deformities) AR was implemented using operating microscope head-up displays (HUDs). Intraoperative low-dose computed tomography was used for automatic registration. Nonlinear image registration was applied to integrate multimodality preoperative images. Target and risk structures displayed by AR were defined in preoperative images by automatic anatomical mapping and additional manual segmentation.

RESULTS

AR could be successfully applied in all 42 cases. Low-dose protocols ensured a low radiation exposure for registration scanning (effective dose cervical 0.29 ± 0.17 mSv, thoracic 3.40 ± 2.38 mSv, lumbar 3.05 ± 0.89 mSv). A low registration error (0.87 ± 0.28 mm) resulted in a reliable AR representation with a close matching of visualized objects and reality, distinctly supporting anatomical orientation in the surgical field. Flexible AR visualization applying either the microscope HUD or video superimposition, including the ability to selectively activate objects of interest, as well as different display modes allowed a smooth integration in the surgical workflow, without disturbing the actual procedure. On average, 7.1 ± 4.6 objects were displayed visualizing target and risk structures reliably.

CONCLUSIONS

Microscope-based AR can be applied successfully to various kinds of spinal procedures. AR improves anatomical orientation in the surgical field supporting the surgeon, as well as it offers a potential tool for education.

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.

Early Experience, Setup, Learning Curve, Benefits, and Complications Associated with Exoscope and Three-Dimensional 4K Hybrid Digital Visualizations in Minimally Invasive Spine Surgery

Study Design

Prospective observational study (n=74).

Purpose

To evaluate the learning curve for exoscope and three-dimensional (3D) 4K hybrid visualization in terms of operating time, advantages, disadvantages, and surgical complications in tubular-access minimally invasive spine surgery (MISS) and to assess surgeon satisfaction with image quality, ergonomics, and ability to perform target site treatment.

Overview of Literature

Working through tubular retractors poses a challenge. The extreme angulations during microsurgical decompression, especially contralateral decompression, require surgeons to work non-ergonomically. An exoscope allows surgeons to work ergonomically and independently of the microscope oculars as visualizations are now provided by large 3D 4K monitors. However, the value and efficacy of solely depending on an exoscope and 3D 4K monitors during microsurgical work are still unknown.

Methods

Seventy-four patients (99 levels) underwent trans-tubular MISS between March 2018 and January 2019. Five patients were excluded: one had pyogenic discitis, two had revisions, and two were trans-tubular transoral. In total, we analyzed 69 for operating time, blood loss, and complications. The learning curve graph was plotted using the surgical time for each procedure. Surgeons were asked to rate their satisfaction with image quality, ability to maintain ergonomic posture, and efficient target site treatment.

Results

For tubular microdiscectomy, the operating time plateaued after six cases, and for tubular decompression and minimally invasive transforaminal lumbar interbody fusion, the operating time plateaued after nine cases. Mean operating time was significantly reduced after the plateau. Complications included four cases of dural tear. All patients improved symptomatically, and there were no postoperative neurological deficits.

Conclusions

Use of the exoscope has a short learning curve. Surgeons benefit from improved ergonomic posture during surgery, and resident teaching appears to be good. The only drawback is the need to rearrange the operating table setup. Complications were comparable to those when using the surgical microscope. An exoscope with hybrid digital visualization provides excellent visualization, depth perception, clarity, and precision target site treatment.

Augmented reality in intradural spinal tumor surgery

BACKGROUND

Microscope-based augmented reality (AR) is commonly used in cranial surgery; however, until recently, this technique was not implemented for spinal surgery. We prospectively investigated, how AR can be applied for intradural spinal tumor surgery.

METHODS

For ten patients with intradural spinal tumors (ependymoma, glioma, hemangioblastoma, meningioma, and metastasis), AR was provided by head-up displays (HUDs) of operating microscopes. User-independent automatic AR registration was established by low-dose intraoperative computed tomography. The objects visualized by AR were segmented in preoperative imaging data; non-linear image registration was applied to consider spine flexibility.

RESULTS

In all cases, AR supported surgery by visualizing the tumor outline and other relevant surrounding structures. The overall AR registration error was 0.72 ± 0.24 mm (mean ± standard deviation), a close matching of visible tumor outline and AR visualization was observed for all cases. Registration scanning resulted in a low effective dose of 0.22 ± 0.16 mSv for cervical and 1.68 ± 0.61 mSv for thoracic lesions. The mean HUD AR usage in relation to microscope time was 51.6 ± 36.7%. The HUD was switched off and turned on again in a range of 2 to 17 times (5.7 ± 4.4 times). Independent of the status of the HUD, the AR visualization was displayed on monitors throughout surgery.

CONCLUSIONS

Microscope-based AR can be reliably applied to intradural spinal tumor surgery. Automatic AR registration ensures high precision and provides an intuitive visualization of the extent of the tumor and surrounding structures. Given this setting, all advanced multi-modality options of cranial AR can also be applied to spinal surgery.

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.