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

Selective Microsurgical Disconnection of Greater Sphenoid Wing Dural Arteriovenous Fistula Through the Subtemporal Approach Under Exoscope Magnification

OBJECTIVE

Sphenoid dural arteriovenous fistulas located on the greater sphenoid wing carry a notable risk of intracranial hemorrhage due to the frequent presence of cortical venous reflux. Because of the challenging embolization procedure, microsurgery remains a valuable option in these cases.

METHODS

In most cases, the fistula is located in the anterolateral endocranial surface of the middle cranial fossa just below the sphenoid ridge; however, in a small subset of cases, the fistula is positioned posteriorly and medially in the region between the foramen ovale and rotundum. The former region can be reached using various frontolateral approaches, whereas the latter region can be accessed through a subtemporal trajectory, minimizing temporal lobe retraction. The exoscope has been gaining popularity for improved magnification, visualization, and surgeon ergonomics expanding the surgeon's possible trajectory in skull base surgery.

RESULTS

We present a targeted subtemporal approach using the exoscope for selective occlusion of an unruptured greater sphenoid wing dural arteriovenous fistula. With proper brain relaxation, a small temporobasal craniotomy opens a direct corridor to the middle cranial fossa. Exoscope-assisted surgery could improve dissection of the middle cranial base and dynamic temporal lobe retraction and expand the range of anteromedial subtemporal trajectories, providing angles that may be challenging to achieve using the operative microscope, as well as improve the surgeon's ergonomic position.

CONCLUSIONS

An exoscopic-assisted subtemporal approach is a feasible, safe, and minimally invasive approach to treat unruptured greater sphenoid wing dural arteriovenous fistulas and could be considered an alternative to endovascular treatment.

Exoscope-assisted spine surgery: Current applications and future directions-A short review

Spine surgery is a critical field that seeks to alleviate pain and restore function in patients with various spinal pathologies. Over the years, spine surgery has seen advancements such as minimally invasive techniques with operative microscopes and robotic surgeries. These techniques, however, demand better visualisation during the procedure. Recently, exoscope-assisted spine surgery has emerged as a promising technological advancement that may revolutionise the field due to its ability to facilitate precise and advanced visualisation techniques that ensure successful outcomes in spine surgeries. The application of exoscopes have improved spine surgeries such as spinal fusion procedures, decompression surgeries, instrumentation surgeries, minimally invasive and complex surgeries. These improvements include enhanced visualisation, improved ergonomics, improved surgical precision, reduced operation times and postoperative infection rates. The integration of robotics in exoscope-assisted spine surgery enables autofocus function, ensuring the integrity of the sterile field, providing superior image quality, resolution and three-dimensional perception. However, challenges such as decrease in depth perception and the lack of long-term follow-up data hinder its widespread adoption. Ethical considerations regarding patient safety, technology dependency, and health inequity add another dimension to these challenges. Despite these challenges, exoscope-assisted spine surgery holds significant potential for transforming clinical practice and improving patient outcomes. This review seeks to provide a concise overview of the benefits and limits of exoscope-assisted spine surgeries, while highlighting its challenges and ethical considerations. Addressing these limitations by conducting large-scale clinical trials and exploring the integration of artificial intelligence (AI) could assist in realising the potential of exoscopes in spine surgery.

Three-Dimensional Exoscope-Assisted Occlusion of a Foraminal Intradural Left L5-S1 Arteriovenous Fistula-Operative Video

Spinal dural arteriovenous fistulas (dAVFs) are a rare type of spinal lesion that can cause severe clinical consequences.1 Early and accurate diagnosis and treatment are crucial to avoid severe complications such as radicular pain, weakness, sensory deficits, and loss of bowel and bladder control.2 Spinal dAVFs are commonly found in the lower thoracic or upper lumbar vertebrae. Spinal dAVFs are the most common spinal vascular malformations, of unknown cause, accounting for 70%-85 % of spinal shunts, with an annual incidence of 5-10 cases/1,000,000.3 Recently, they have been classified into extradural and intradural types, which may be further divided into dorsal and ventral lesions.4,5 Spine magnetic resonance imaging (MRI) is the most performed imaging study for suspected dAVF diagnosis.1 Catheter digital subtraction angiography (DSA) represents the gold-standard diagnosing technique. It provides critical information about the anatomy of the lesion, arterial inflow vessels, venous outflow, and endovascular treatment feasibility. DSA may also detect typical structures at risk during treatment.6 Surgical interruption of dAVF offers a complete cure, with low complication rates. Endovascular embolization might be safe and efficient, with high success rates, for selected vascular lesions.7,8 This video presents a rare case of left L5-S1 dAVF, surgically occluded with the aid of a three-dimensional (3D) exoscope (Video 1). There is little evidence about the application of the 3D exoscope in spinal vascular microsurgery, whereas it has been widely used and described in cranial surgery and spinal, degenerative, tumor, and traumatic surgery.9 In our experience, the advantages of this operating tool are the sharp color vividness, which allows adequate discrimination of anatomic structures, the distinct depth perception, the educational value for operating room attendants, and the ergonomics for surgeons. Ergonomics for surgeons, especially, is optimally adapted to spinal surgery, given the contraposed placement of surgeons and the disposition of screens during the operating procedure.

Three-dimensional microscope skill acquisition: A randomised controlled study comparing two-dimensional laboratory microscope training, video gaming and virtual reality gaming

INTRODUCTION

Fine microsurgical motor skill acquisition can be challenging. With increasing technological innovation, the methods of microsurgical skills acquisition may change. Studies show that laboratory-based microsurgical training programmes on a 2D microscope significantly improves the microsurgical skill acquisition of novices. However, it remains to be seen if these skills are transferable to a 3D microscope or if gaming agility is more important? We present a randomised control trial of three interventions, namely laboratory tabletop microscope training (LM), high-fidelity video gaming (Sony PlayStation 4 console; VG) and high-fidelity virtual reality gaming (Sony PlayStation VR console; VR) versus a control group.

METHODS

Forty novice medical students were block randomised to four groups: control (no intervention) n = 10, LM n = 10, VG n = 10 and VR n = 10. Participants performed chicken femoral artery anastomosis using the Aesculap Aeos® 3D microscope platform at the baseline and again after the intervention. Performance was evaluated using a modified structured assessment of microsurgery skills (mSAMS) score, time taken to complete anastomosis and time taken for suture placement by two blinded independent assessors.

RESULT

No statistically significant difference was noted between the groups at the baseline. There was a statistically significant improvement in the LM arm between the baseline and post-training for mSAMS score and time for suture placement. In the VG, VR and control groups no statistically significant difference was observed.

CONCLUSION

Our study demonstrates that during early microsurgical training, an intense laboratory-based microsurgical training programme significantly improves a novice's anastomotic performance on a 2D microscope, and these skills are transferable when a 3D anastomosis is carried out. However, focused gaming had no significant effect, and the results were akin to that of the non-intervention group.

Enabling Technologies in the Management of Cervical Spine Trauma

STUDY DESIGN

Narrative review.

OBJECTIVE

The objective of this study is to explore and evaluate the role of novel technologies in enhancing the diagnosis, surgical precision, and rehabilitation of cervical spine trauma, and to discuss their potential impact on clinical outcomes.

SUMMARY OF BACKGROUND DATA

Traumatic cervical spine injuries are challenging to manage due to their complex anatomy, the potential for long-term disability, and severe neurological deficits. Traditional management approaches are being supplemented by emerging technologies that promise to improve patient care and outcomes.

METHODS

A literature review was conducted to identify and analyze advancements in imaging, navigation, robotics, and wearable technologies in the context of cervical spine trauma. The review focuses on the potential of these technologies to improve early detection, surgical accuracy, and postoperative recovery.

RESULTS

Technological innovations, including advanced imaging techniques, machine learning for diagnostics, augmented reality, and robotic-assisted surgery, are transforming the management of cervical spine trauma. These tools contribute to more efficient, accurate, and personalized treatment approaches, potentially improving clinical outcomes and reducing patient care burdens.

CONCLUSIONS

Although these technologies hold great promise, challenges such as implementation costs and the need for specialized training must be addressed. With continued research and interdisciplinary collaboration, these advancements can significantly enhance the management of cervical spine trauma, improving patient recovery and quality of life.

LEVEL OF EVIDENCE

Level V.

Evolution of Thoracic Disc Herniation Surgery: Future Perspectives from a Systematic Review and Meta-Analysis

BACKGROUND

The neurosurgical treatment of thoracic disc herniation (TDH) has undergone dramatic changes over the years in terms of surgical approaches and intraoperative technological tools. There is still no unanimous consent on the criteria for approach selection, and the choice varies among Institutions. The aim of this study is to compare anterior and posterolateral approaches for TDH in terms of functional and surgical outcomes.

METHODS

A systematic literature review and meta-analysis according to PRISMA guidelines from EMBASE, PubMed, Cochrane Library, Web of Science, and Google Scholar online databases up to May 2024 incorporated studies that reported outcomes of thoracic disc herniation surgeries. Analyzed factors included major peri- and postoperative complications, intraoperative blood loss, hospital stay, neurological improvement, and complete hernia resection. Random-effect models were used to calculate pooled odds ratios and mean differences.

RESULTS

The posterolateral approach was associated with significantly lower rates of major medical (OR 0.14, 95% CI: 0.07 to 0.27) and surgical complications (OR 0.61, 95% CI: 0.38 to 0.99) compared to the anterior approach. Additionally, posterolateral approaches reduced intraoperative blood loss and shorter hospital stays. Posterolateral techniques were linked to higher odds of neurological improvement (OR 0.65, 95% CI: 0.43 to 0.99) and higher rates of complete hernia resection (OR 0.38, 95% CI: 0.21 to 0.71).

CONCLUSIONS

Posterolateral approaches offer advantages in terms of safety, recovery, neurological improvement, and complete hernia resection. More extensive prospective studies are needed to confirm these findings and refine surgical strategies. Emerging technologies, such as the exoscope and 45° endoscopy, may further enhance surgical outcomes.

Exoscope as a financially viable solution for micro neurosurgery in low-middle-income countries

Operating microscope is a backbone for the development of micro neurosurgery. In resource-limited setups and low-income countries, the volume of annual microsurgical procedures is low due to lack of the required equipment, one of which is the operating microscope. The price of currently available operating microscopes makes it difficult to address this issue in resource-constrained areas and low-income countries. Exoscope with a relatively lower price and the same even better imaging qualities can be used as an option for this problem.

Challenges in Contemporary Spine Surgery: A Comprehensive Review of Surgical, Technological, and Patient-Specific Issues

Spine surgery has significantly progressed due to innovations in surgical techniques, technology, and a deeper understanding of spinal pathology. However, numerous challenges persist, complicating successful outcomes. Anatomical intricacies at transitional junctions demand precise surgical expertise to avoid complications. Technical challenges, such as underestimation of the density of fixed vertebrae, individual vertebral characteristics, and the angle of pedicle inclination, pose additional risks during surgery. Patient anatomical variability and prior surgeries add layers of difficulty, often necessitating thorough pre- and intraoperative planning. Technological challenges involve the integration of artificial intelligence (AI) and advanced visualization systems. AI offers predictive capabilities but is limited by the need for large, high-quality datasets and the "black box" nature of machine learning models, which complicates clinical decision making. Visualization technologies like augmented reality and robotic surgery enhance precision but come with operational and cost-related hurdles. Patient-specific challenges include managing postoperative complications such as adjacent segment disease, hardware failure, and neurological deficits. Effective patient outcome measurement is critical, yet existing metrics often fail to capture the full scope of patient experiences. Proper patient selection for procedures is essential to minimize risks and improve outcomes, but criteria can be inconsistent and complex. There is the need for continued technological innovation, improved patient-specific outcome measures, and enhanced surgical education through simulation-based training. Integrating AI in preoperative planning and developing comprehensive databases for spinal pathologies can aid in creating more accurate, generalizable models. A holistic approach that combines technological advancements with personalized patient care and ongoing education is essential for addressing these challenges and improving spine surgery outcomes.

High-Definition 4K-3D Exoscope in Spine Surgery: A Single-Center Experience and Review of the Literature

Background and Objectives: Binocular optical microscopy (OM) paved the way for a new era in brain and spine neurosurgery fields with the introduction of microsurgery. Despite its enormous contribution to modern neurosurgery, OM presents some intrinsic limitations that surgeons need to face during procedures such as prolonged non-ergonomic positions and decreased vision quality to the assistant eyepiece. To overcome these limitations, in recent years, new operative tools have been introduced, such as exoscopes. Here, we present our experience with exoscopes in spine surgery. Materials and Methods: In the period between January 2022 and December 2023, we gradually implemented the use of a high-definition 4K-3D exoscope (ORBEYETM, Olympus, Japan) in patients undergoing spinal surgery. Results: A total of 243 patients underwent spine surgery with exoscope magnification (47 intradural tumors, 99 lumbar degenerative cases, 79 cervical degenerative cases, 5 dorsal calcified disk herniations, 4 dural arteriovenous fistulas (dAVFs), and 9 others). We compared this cohort with a similar cohort of patients operated in the same period using OM based on different endpoints: operating time, complication rate, and infection rate. We did not find any statistically significant difference in any of the endpoints between these two groups. Conclusions: In our experience, the exoscope provides a better resolution of spinal anatomy and higher quality real-time images of the surgery for the entire OR team and improves the ergonomic posture of both surgeons, without lengthening the operating time and without increasing the rate of adverse events. Prospective studies with a larger cohort of patients are needed to further validate these findings.

Embracing Exoscope in the Arsenal of Spine Surgeons in the Low- and Middle-Income Countries

BACKGROUND

Exoscope (EX) is a device that combines the convenience of an endoscope with the image clarity of an operating microscope (OM) to fill the void between the two. This study aims to compare the 2-dimensional EX with OM in spine surgeries and to explore its utility and feasibility in small and peripheral hospitals of low- and middle-income countries.

METHODS

Eighty-two patients with intradural spinal tumors (extramedullary and intramedullary) aged more than 18 years were included between August 2021 and August 2023. Patients with other spinal pathologies were excluded. After each exoscopic surgery, the operating surgeon and assistant had to answer a questionnaire. Postoperatively, outcomes were measured as the length of hospital stay, cerebrospinal fluid leak, and number of reoperations.

RESULTS

Thirty-seven patients were included in the OM group and 45 patients were included in the EX group. In 62%-67% of cases, the overall image quality of the EX was comparable to OM and in 29%-38% of cases, it was superior to the OM. The preparation and installation of the EX were much easier and better than the OM in 93%-100% of the cases. Maneuvering surgical instruments and workflow in the operating theater was much more convenient in the EX group (95%-100% of the cases). Ergonomics was far better in the EX group than in the OM group.

CONCLUSIONS

Spine surgeons can embrace the benefits of EX and increase their range of surgeries to be performed at the small operation theater setup in low-middle income developing countries.

Exoscope Use in Spine Surgery: A Systematic Review of Applications, Benefits, and Limitations

BACKGROUND

Exoscopes were recently developed as an alternative to the operative microscope (OM) and endoscope for intraoperative visualization during neurosurgery. Prior reviews studying mixed cranial and spinal surgical cohorts reported advantages with exoscope use, including improved ergonomics and teaching. In recent years, there has been an increase in exoscope research, with no updated systematic review focused exclusively on the benefits and limitations of exoscope use in spine surgery. Thus, we sought to systematically synthesize the literature related to exoscope-assisted spine surgery.

METHODS

A literature search was conducted using the PubMed, Embase, Scopus, Cochrane, and Web of Science databases to identify relevant studies reported between 2010 and September 2023. Data, such as the exoscope model used, procedure types performed, and user observations, were then collected.

RESULTS

A total of 31 studies met our inclusion criteria, including 481 patients with spine pathologies who underwent a surgical procedure using 1 of 9 exoscope models. The lumbar region was the most frequently operated area (n = 234; 48.6%), and discectomies comprised the most overall procedures (n = 273; 56.8%). All patients benefited clinically. The reported advantages of exoscopes compared with OMs or endoscopes were improved focal distance, surgeon posture, trainee education, compactness, and assistant participation. Other aspects such as stereopsis, illumination, and cost had various observations.

CONCLUSIONS

Exoscopes have advantages compared with OMs or endoscopes during spine surgery. The user learning curve is minimal, and no negative patient outcomes have been reported. However, some aspects of exoscope use necessitate longer term prospective research before exoscopes can be considered a standard tool in the armamentarium of intraoperative visualization strategies.

Exoscope Efficacy and Feasibility in Pediatric Spinal Neurosurgery: A Single-Institution Cohort Case Series

BACKGROUND

The exoscope has emerged as an efficacious microscope in adult spinal neurosurgery providing improved operative field visibility and surgeon ergonomics. However, outcome data and feasibility are underrepresented in the pediatric literature. We present the largest case series aimed at assessing operative and clinical outcomes in pediatric patients undergoing various exoscope-assisted spinal surgeries.

METHODS

A retrospective review was conducted on all consecutive pediatric (age <18 years) spinal surgeries performed with the use of an exoscope by 3 senior surgeons at a single institution from 2020-2023. Demographics and clinical and operative outcomes were reviewed and analyzed.

RESULTS

Ninety-six exoscope-assisted pediatric spine surgeries were performed on 89 unique patients, 41 (42.7%) of which were male. The mean age at surgery was 12 (±5.3) years. Spinal cord detethering (55.8%) was the most common procedure performed. The overall mean operative time for all procedures was 155 (±86) minutes, and the mean estimated blood loss was 18 (±41) mL. The mean length of stay was 5.4 (±6.5) days. There were 14 (14.6%) patients with complications in this cohort. At final follow-up, 64 (83.1%) of symptomatic patients reported neurologic symptom improvement.

CONCLUSIONS

Using the exoscope in a variety of pediatric spinal surgeries resulted in an acceptable average operative time, estimated blood loss, length of stay, and rate of neurologic symptom improvement. The exoscope appears to be an efficacious option for pediatric neurosurgical spinal procedures.

The New Era of Spinal Surgery: Exploring the Use of Exoscopes as a Viable Alternative to Operative Microscopes-A Systematic Review and Meta-Analysis

BACKGROUND

The growing interest in exoscopic (EX) technology has prompted a comprehensive evaluation of its clinical, functional, and financial outcomes in neurosurgery. This systematic review and meta-analysis aimed to explore the utilization of EX in spine surgery and assess their safety, efficacy, and impact on surgical outcomes.

METHODS

A thorough literature review was conducted using PubMed, Scopus, and Embase databases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The study focused on articles concerning the application of EXs in spinal surgical procedures. The inclusion criteria encompassed various study designs presenting clinical data and intraoperative experiences related to EX utilization in spine surgery.

RESULTS

The meta-analysis included studies examining various aspects of EX utilization, such as intraoperative complications, video/image quality, surgical field visualization, ease of manipulation, ergonomic characteristics, educational utility, surgical duration, and team involvement. Findings indicated that EXs offered superior video quality and favorable ergonomic features. Comparable outcomes were observed in surgical duration, intraoperative blood loss, time to discharge, and postoperative pain levels between EX and conventional microscope approaches.

CONCLUSIONS

This study provides valuable insights into the utilization of EXs in spine surgery, demonstrating their potential advantages and comparable outcomes with conventional microscopes.

Cadaveric study of ergonomics and performance using a robotic exoscope with a head-mounted display in spine surgery

The conventional microscope has the disadvantage of a potentially unergonomic posture for the surgeon, which can affect performance. Monitor-based exoscopes could provide a more ergonomic posture, as already shown in pre-clinical studies. The aim of this study was to test the usability and comfort of a novel head-mounted display (HMD)-based exoscope on spinal surgical approaches in a simulated OR setting. A total of 21 neurosurgeons naïve to the device were participated in this prospective trial. After a standardized training session with the device, participants were asked to perform a single-level thoracolumbar decompression surgery on human cadavers using the exoscope. Subsequently, all participants completed a comfort and safety questionnaire. For the objective evaluation of the performance, all interventions were videotaped and analyzed. Twelve men and nine women with a mean age of 34 (range: 24-57) were participating in the study. Average time for decompression was 15 min (IqR 9.6; 24.2); three participants (14%) terminated the procedure prematurely. In these dropouts, a significantly higher incidence of back/neck pain (p = 0.002 for back, p = 0.046 for neck pain) as well as an increased frequency of HMD readjustments (p = 0.045) and decreased depth perception (p = 0.03) were documented. Overall, the surgeons' satisfaction with the exoscope was 84% (IqR 75; 100). Using a standardized, pre-interventional training, it is possible for exoscope-naïve surgeons to perform sufficient spinal decompression using the HMD-based exoscope with a high satisfaction. However, inaccurate HMD setup prior to the start of the procedure may lead to discomfort and unsatisfactory results.

Comparison of efficacy between endoscope-assisted anterior cervical discectomy and fusion (ACDF) and open ACDF in the treatment of single-segment cervical spondylotic myelopathy

BACKGROUND

In this study, we compared the clinical efficacy of endoscope-assisted anterior cervical discectomy and fusion (ACDF) with open ACDF in the treatment of single-segment cervical spondylotic myelopathy.

METHODS

A retrospective analysis was performed on 52 patients with single-segment cervical spondylotic myelopathy between June 2021 and February 2022, including 33 males and 19 females, with a mean age of 58.42 ± 9.26) years. Among them, 28 patients were treated with endoscope-assisted ACDF (Group A), including 2 cases of C4/5 segment, 16 cases of C5/6 segment, and 10 cases of C6/7 segment; 24 patients were treated with open ACDF (Group B), including 4 cases of C4/5 segment, 11 cases of C5/6 segment, and 9 cases of C6/7 segment. The operation time, intraoperative blood loss, hospital stay, and complications were recorded and compared between the two groups. The Visual Analogue Scale (VAS) and the Japanese Orthopaedic Association (JOA) score were used for clinical evaluation during the follow-up in the 1st month and 3rd month after surgery, and at the final follow-up.

RESULTS

The 52 patients were followed up on average for 13.04 months (12-17 months). The operation time in Group A and Group B was (105.18 + 8.66) minutes and (81.88 + 6.05) minutes, the intraoperative blood loss was (84.29 + 13.45) mL and (112.92 + 17.81) mL, and the hospital stay was (6.75 + 1.29) days and (7.63 + 1.41) days, respectively. The difference between the two groups was statistically significant (P < 0.05). The VAS and JOA scores in the 1st month and the 3rd month after surgery and the last follow-up significantly improved in both groups compared with those before surgery (P < 0.05). The VAS and JOA scores of Group A in the 1st month, 3rd month after surgery, and the last follow-up were better than those in Group B (P < 0.05). The complication rate in Group A was 7% (2/28), which was not significantly different from the 17% (4/24) in Group B (P > 0.05).

CONCLUSION

Both endoscope-assisted ACDF and open ACDF can achieve satisfactory clinical efficacy in the treatment of single-segment cervical spondylotic myelopathy. Although the operation time of endoscope-assisted ACDF is prolonged, it has the advantages of clear vision, thorough decompression, less blood loss, and reduced risk of nerve damage, and is worthy of clinical promotion and application.

Comparative analysis of exoscope-assisted spine surgery versus operating microscope: A systematic review

Background

Limitations in the operative microscope (OM)'s mobility and suboptimal ergonomics created the opportunity for the development of the exoscope. This systematic review aims to evaluate the advantages and disadvantages of exoscopes and OMs in spine surgery.

Methods

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a systematic search was conducted in the major research databases. All studies evaluating the exoscopes and/or OMs in spinal procedures were included.

Results

There were 602 patients included in the 16 studies, with 539 spine surgery patients, 19 vascular cases, 1 neural pathology case, 19 cranial cases, and 24 tumor pathologies. When examining surgical outcomes with the exoscope, results were mixed. Compared to the OM, exoscope usage resulted in longer operative times in 7 studies, comparable times in 3 studies, and shorter operative times in 3 studies. Two studies found similar lengths of stay (LOS) for both tools, two reported longer LOS with exoscopes, and one indicated shorter hospital LOS with exoscopes. One study reported higher exoscope-related blood loss (EBL), but four other studies consistently showed reduced EBL. In terms of image quality, illumination, dynamic range, depth perception, ergonomics and cost-effectiveness, the exoscope was consistently rated superior, while findings across studies were mixed regarding the optical zoom ratio and mean scope adjustment (MSA). The learning curve for exoscope use was consistently reported as shorter in all studies.

Conclusion

Exoscopes present a viable alternative to OMs in spine surgery, offering multiple advantages, which supports their promising role in modern neurosurgical practice.

From Microscopic to Exoscopic Microsurgery: Are We Facing a Change of Paradigm?

BACKGROUND

Neurosurgery is a medical branch characterized by small and deep surgical field with the need of manipulation and dissection of anatomical structures. High light and magnification are required in order to avoid injuries to important anatomical structures and to avoid permanent neurological deficits. Introduction of operative microscope made a change of paradigm in neurosurgery allowing to better see what could not be seen with common light. Nowadays, introduction of several technologies have increased the safety and efficacy of neurosurgery. Among new technologies, the 3D exoscope is emerging pretending to shift the paradigm of microneurosurgery. In this work, we aim to show our first experience with the use of the exoscope showing advantages and disadvantages.

MATERIALS AND METHODS

We reviewed our surgical database from the introduction of the exoscope in our department (in November 2020 temporarily; then from November 2021 definitively) searching for all the microsurgery interventions performed in the period.

RESULTS

From the introduction of the exoscope in our department, we operated 244 cases with the OM and 228 with the exoscope. We operated 175 lesions located in the supratentorial compartment, 29 in the infratentorial, and 24 in the spinal column. Regarding the OM, the ratios were as follows: 122 females and 122 males; 235 adults and 9 children; 66 supratentorial lesions, 14 infratentorial lesions, and 164 spine surgeries. Our team showed a progressive switch from the microscope to the exoscope. Only one member of our team preferred to continue to use the standard operative microscope.

CONCLUSIONS

Our experience showed no complications related to the use of the exoscope that proved to be safe and effective both for surgery and teaching.

Mortality After Microsurgical Treatment of Unruptured Intracranial Aneurysms in the Modern Era

BACKGROUND

The incidence of mortality after treatment of unruptured intracranial aneurysms (UIAs) has been described historically. However, many advances in microsurgical treatment have since emerged, and most available data are outdated. We analyzed the incidence of mortality after microsurgical treatment of patients with UIAs treated in the past decade.

METHODS

The medical records of all patients with UIAs who underwent elective treatment at our large quaternary center from January 1, 2014, to December 31, 2020, were reviewed retrospectively. We analyzed mortality at discharge and 1-year follow-up as the primary outcome using univariate to multivariable progression with P < 0.20 inclusion.

RESULTS

During the 7-year study period, 488 patients (mean [SD] age = 58 [12] years) had UIAs treated microsurgically. Of these patients, 61 (12.5%) had a prior subarachnoid hemorrhage. One patient (0.2%) with a dolichoectatic vertebrobasilar aneurysm died while hospitalized, and 7 other patients (8 total; 1.6%) were determined to have died at 1-year follow-up (1 trauma, 2 myocardial infarction, 2 cerebrovascular accident, 1 pulmonary embolism, and 1 subdural hematoma complicated by abscess). On univariate analysis, significant risk factors for mortality at follow-up included diabetes mellitus, preoperative anticoagulant or antiplatelet use, aneurysm calcification, nonsaccular aneurysm, and higher American Society of Anesthesiologists grades (all P < 0.03). On multivariable logistic regression analysis, only nonsaccular aneurysms and higher American Society of Anesthesiologists grades were predictors of mortality.

CONCLUSIONS

A low mortality rate is associated with recent microsurgical treatment of UIAs. However, nonsaccular aneurysms and higher American Society of Anesthesiologists grades appear to be predictors of mortality.

Preliminary Clinical Experience with a High-Definition Three Dimensional Exoscope for Spinal Surgery

We retrospectively evaluated spinal surgeries performed using the high-definition three-dimensional exoscopic system, which became available at our institution in August 2020. Eleven patients (4 with cervical disease and 7 with lumbar disease) underwent surgery with the system. There were no surgical complications related to the system, and the results were satisfactory. The small, flexible camera of the exoscope allows the surgeon to view the surgical field from various angles, facilitating both the approach and technique. In addition, it allows the surgeon to operate in an upright position without strain on the head and neck. Although further surgical experience is needed, this system has the potential to improve the visualization of the surgical field in spinal surgery.

Application of the Robotic-Assisted Digital Exoscope for Resection of Posterior Fossa Tumors in Adults: A Series of 45 Cases

BACKGROUND AND OBJECTIVES

Complete safe resection is the goal when pursuing surgical treatment for posterior fossa (PF) tumors. Efforts have led to the development of the exoscope that delineates tumors from non-neoplastic brain. This investigation aims to assess patient outcomes where PF tumor resection is performed with the exoscope by a retromastoid or suboccipital approach.

METHODS

A retrospective analysis was conducted for patients with PF tumors who underwent exoscope resection from 2017 to 2022. Patient demographics, clinical, operative, and outcome findings were collected. Extent of resection studies were also performed. Associations between perioperative data, discharge disposition, progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

A total of 45 patients (22 male patients) with a median age of 57 years were assessed. Eighteen (40%) and 27 patients (60%) were diagnosed with malignant and benign tumors, respectively. Tumor neurovascular involvement was found in 28 patients (62%). Twenty-four (53%) and 20 (44%) tumors formed in the cerebellum and cerebellopontine angle cistern, respectively. One tumor (2%) was found in the cervicomedullary junction. The mean extent of resection was 96.7% for benign and malignant tumors. The PFS and OS rate at 6 months (PFS6, OS6) was 89.7% and 95.5%, respectively. Neurological complications included sensory loss and motor deficit, with 11 patients reporting no postoperative symptoms. Of the neurological complications, 14 were temporary and 9 were permanent.

CONCLUSION

The exoscope is an effective intraoperative visualization tool for delineating PF tumors. In our series, we achieved low postoperative tumor volumes and a high gross total resection rate.

Advantages of 3-dimensional exoscope-assisted anterior cervical spine surgery: A meta-analysis

BACKGROUND

Visual instruments are essential to ensure high-quality surgical outcomes for minimally invasive procedures and have gradually become the focus of research. Recently, a novel visual auxiliary instrument, a 3-dimensional exoscope (EX), has been applied for spinal surgery. However, its advantages over other auxiliary means (OAMs) in anterior cervical surgery need to be assessed.

OBJECTIVE

To compare and evaluate the clinical outcomes of EX and OAMs in anterior cervical spine surgery using a meta-analysis and to provide the latest clinical evidence.

METHODS

PubMed, Embase, Cochrane Library, Web of Science, CNKI, and Wanfang Database were systematically reviewed for relevant literature published prior to January 21, 2023. Two researchers independently screened the literature, extracted data, and assessed bias risk in the included literature. Review Manager software (version 5.4; the Cochrane Collaboration) was used to conduct the meta-analysis.

RESULTS

five studies, one prospective and four retrospective cohort studies, with a total of 349 patients (154 in the EX group and 195 in the OAMs group) were included. A meta-analysis showed that compared to OAMs, EX-assisted anterior cervical spine surgery resulted in less intraoperative hemorrhage [WMD = -8.96, 95% CI (-14.21, -3.71), P = 0.0008]. Nevertheless, no significant differences in VAS scores, JOA scores, operation time, hospitalization time, and complication rate were observed between the two groups (P > 0.05).

CONCLUSION

EX and OAMs are equally safe and effective for anterior cervical spine surgery; however, compared to OAMs, EX results in less intraoperative hemorrhage.

Accessible Spinal Surgery: Transformation Through the Implementation of Exoscopes As Substitutes for Conventional Microsurgery in Low- and Middle-Income Settings

Advancements in neurosurgical visualization have been made possible by the introduction of the operating microscope (OM) and the emergence of exoscopic technology (EX). Both OMs and EXs provide enhanced magnification and illumination, but they come with their own set of advantages and disadvantages. OMs provide high-quality magnification and illumination and have been used successfully in a variety of surgical procedures. They can be customized to fit the specific needs of the surgeon and are a well-established technology. However, they can be bulky, expensive, and cause discomfort during extended procedures. EXs provide high-definition magnification and illumination, improved depth perception and ergonomics, and can be cost-effective. They can be customized to fit the specific needs of the surgeon and can be made using locally available materials, reducing the need for expensive imports. However, they may require adjustment and have a learning curve for surgeons who are used to operating with OMs. Additionally, they may have limited availability in some healthcare settings. The choice between OMs and EXs will depend on the specific needs of the surgeon and the healthcare setting. The integration of 3D EX systems has revolutionized neurosurgery, offering improved depth perception and ergonomics. EX's cost-effectiveness addresses accessibility concerns, making it an attractive alternative, particularly for low and middle-income healthcare settings. The exoscope seems to be a safe alternative compared to an operative microscope for the most common brain and spinal procedures. The exoscope may help expand access to neurosurgical care and training worldwide. In conclusion, both technologies have their own set of advantages and disadvantages, and the choice between them will depend on the specific needs of the surgeon and the healthcare setting.

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.

Minimally invasive microsurgical decompression of the lumbar spine using a novel robotised digital microscope: A preliminary experience

BACKGROUND

The operative microscope (OM) represents, to date, the standard for neurosurgical procedures. However, new technologies have been proposed during the latest years to overcome its limitations, from high-quality exoscopes to complex robotised visualisation systems. We report our preliminary experience with a novel digital robotised microscope, the BHS RoboticScope (RS), for minimally invasive spinal surgery.

METHODS

We employed the RS in five consecutive patients who underwent bilateral lumbar spine decompression through a monolateral approach. Patient outcomes, device technical characteristics and the surgeon's personal perspectives have been evaluated.

RESULTS

No complications occurred. All procedures were concluded without switching to the microscope. Image quality, lightning, depth perception and freedom of movement were judged satisfactory as compared to the standard microscope.

CONCLUSION

The easy maneuverability and the high quality of pictures provided by the RS device improve the surgeon's comfort in deep fields, representing an effective option for minimally invasive spinal procedures.

Comparative survey study of the use of a low cost exoscope vs. microscope for anterior cervical discectomy and fusion (ACDF)

Background

Anterior cervical discectomy and fusion (ACDF) is an often performed procedure in spine neurosurgery. These are often performed using an operating microscope (OM) for better illumination and visualization. But its use is limited to the surgeon and the assistant. There is difficulty in maneuvering long surgical instruments due to the limited space available. Exoscope (EX) has been used as an alternative to microscopes and endoscopes. We used an EX in patients undergoing ACDF for cervical spondylotic myelopathy.

Methods

A prospective comparative trial was conducted to test the safety and usability of a low-cost EX compared to a conventional surgical binocular OM in ACDF. Twenty-six patients with degenerative cervical myelopathy symptoms were operated by ACDF assisted by the EX and OM between December 2021 and June 2022. The authors collected and compared data on operative time, intraoperative hemorrhage, hospital admission, and complications in the two groups.

Results

There were no statistically significant differences between the two groups in mean operative time, hospital stay, or postoperative complications. The average intraoperative blood loss was significantly more in the OM group. There were no surgical complications related to the use of the EX or OM. The comfort level, preoperative setup and intraoperative adjustment of position and angle of the EX were rated higher than the OM group. The image quality, depth perception, and illumination were rated as inferior to that of the OM. The low-cost EX was rated to be superior to that of the OM with regard to education and training purposes.

Conclusion

Our study showed that the low-cost EX appears to be a safe and effective alternative for OM-assisted ACDF with great comfort and ergonomics and serves as an essential tool for education and training purposes. However, some limitations of our EX included slightly inferior image quality and illumination when compared with the OM.

The Impact of a Robotic Digital Microscope on the Ergonomics in a Neurosurgical Operating Theatre (A Single-Centre Experience)

Ergonomics is an emerging concept in the neurosurgical operating theatre, where neurosurgeons work under great concentration and frequently neglect their uncomfortable body posture. Work-related musculoskeletal disorders (WMSD) are becoming a widespread burden in the neurosurgical community. WMSD have a negative impact on surgical performance and decrease the surgeons' quality of life. Here we present our single-centre 2-month experience with the Aesculap AEOS® Robotic Digital Microscope (RDM) and prospectively calculate the REBA (Rapid Entire Body Assessment) scores and compare them with similar neurosurgical cases operated with a conventional operative microscope (OPMI).Materials and Methods: For a period of 2 months at the Department of Neurosurgery of the University Hospital Pirogov, Sofia, Bulgaria, 41 consecutive patients were operated on using RDM. The REBA employee assessment worksheets were filled in prospectively to assess the ergonomics of the senior author (N.G.) while using the RDM and the OPMI.Results and Conclusion: The ergonomics during neurosurgical operations could be substantially improved with the implementation of the exoscope. For challenging cranial approaches, where the operator must frequently "look around corners" the exoscope has a major advantage compared with the OPMI-the REBA score is 2.6 times lower for the exoscope and reaches a low risk for WMSD. For spinal operations, the neck score as part of the REBA score is three times lower for the exoscope.

Exoscope improves visualization and extent of hippocampal resection in temporal lobectomy

INTRODUCTION

Anterior temporal lobectomy (ATL) is a safe and well-validated procedure in the treatment of temporal lobe epilepsy (TLE), but is a challenging technique to master and still confers a risk of morbidity and mortality due to the complex anatomy of the mesial temporal lobe structures. Automated robotic 3D exoscopes have been developed to address limitations traditionally associated with microscopic visualization, allowing for ergonomic, high-definition 3D visualization with hands-free control of the robot. Given the potential advantages of using such a system for visualization of complex anatomy seen during mesial structure resection in ATL, this group sought to investigate impact on the percentage of hippocampal resection in both exoscope and microscope guided procedures.

METHODS

We conducted a retrospective analysis of 20 consecutive patients undergoing standard ATL for treatment of medically refractory TLE at our institution. Using pre-operative and post-operative imaging, the coronal plane cuts in which either the head, body, or tail of the hippocampus appeared were counted. The number of cuts in which the hippocampus appeared were multiplied by slice thickness to estimate hippocampal length.

RESULTS

Mean percentage of hippocampal resection was 61.1 (SD 13.1) and 76.5 (SD 6.5) for microscope and exoscope visualization, respectively (p = 0.0037).

CONCLUSION

Use of exoscope for mesial resection during ATL has provided good visualization for those in the operating room and the potential for a safe increase in hippocampal resection in our series. Further investigation of its applications should be evaluated to see if it will improve outcomes.

Expanding access to microneurosurgery in low-resource settings: Feasibility of a low-cost exoscope in transforaminal lumbar interbody fusion

Objectives

Less than a quarter of the world population has access to microneurosurgical care within a range of 2 h. We introduce a simplified exoscopic visualization system for low-resource settings.

Materials and Methods

We purchased a 48 megapixels microscope camera with a c-mount lens and a ring light at a total cost of US$ 125. Sixteen patients with lumbar degenerative disk disease were divided into an exoscope group and a microscope group. In each group, we performed four open and four minimally invasive transforaminal lumbar interbody fusions (TLIF). We conducted a questionnaire-based assessment of the user experience.

Results

The exoscope achieved similar outcomes with comparable blood loss and operating time as the microscope. It provided similar image quality and magnification. Yet, it lacked stereoscopic perception and the adjustability of the camera position was cumbersome. Most users strongly agreed the exoscope would significantly improve surgical teaching. Over 75% reported that they would recommend the exoscope to colleagues and all users saw its great potential for low-resource environments.

Conclusion

Our low-budget exoscope is safe and feasible for TLIF and purchasable at a fraction of the cost of conventional microscopes. It may thus help expand access to neurosurgical care and training worldwide.

Implementation of a three-dimensional (3D) robotic digital microscope (AEOS) in spinal procedures

Three-dimensional exoscopes have been designed to overcome certain insufficiencies of operative microscopes. We aimed to explore the clinical use in various spinal surgeries. We performed surgery on patients with different spine entities in a neurosurgical department according to the current standard operating procedures over a 4-week period of time. The microsurgical part has been performed with Aesculap AEOS 3D microscope. Three neurosurgeons with different degree of surgical expertise completed a questionnaire with 43 items based on intraoperative handling and feasibility after the procedures. We collected and analyzed data from seventeen patients (35% male/65% female) with a median age of 70 years [CI 47-86] and median BMI of 25.8 kg/m2 [range 21-33]. We included a variety of spinal pathologies (10 degenerative, 4 tumor and 3 infectious cases) with different level of complexity. Regarding setup conflicts we observed issues with adjustment of the monitor position or while using additional equipment (e.g. fluoroscopy in fusion surgery) (p = 0.007/p = 0.001). However image resolution and sharpness as well as 3D-depth perception were completely satisfactory for all surgeons in all procedures. The utilization of the exoscopic arm was easy for 76.5% of the surgeons, and all of them declared a significant improvement of the surgical corridor. The 3D-exoscope implementation appears to achieve very satisfactory results in spinal procedures especially with minimally invasive approaches.

A Novel Use of the Exoscope for In-Vivo Microvascular Free Flaps

Recent innovations in camera and display technologies have created a new potential modus for the microvascular surgeon. An exoscope consists of cameras mounted to a flexible arm that broadcasts the image to a nearby high-definition monitor. This article details the experience using this emerging technology to perform microvascular anastomosis for 46 cases of head and neck free flaps reconstruction. The exoscope is compared against the operating microscope and we conclude that the exoscope is a viable substitute when performing microvascular anastomosis with some advantages in the areas of surgeon comfort and viewing angulation.

High-definition two-dimension video telescope operating monitor-assisted brain and spinal surgery in pediatrics: is it an acceptable substitute for microscopic surgery?

PURPOSE

Vision and ergonomics are crucial variables for successful outcomes during neurosurgery procedures. Two-dimension video telescope operating monitor (VITOM) exoscope has emerged as an alternative, which is cheaper than microscope. The aim of this study is to evaluate the clinical utility of 2D VITOM and to compare its merits and demerits with respect to microscope.

METHODS

VITOM 2D (Karl Storz, Germany) was used in 9 cranial and 5 spinal pediatric cases. While KINEVO operative microscope (Carl Zeiss, Germany) was used in 12 cranial and 6 spinal pediatric patients. All surgeries were performed by single senior neurosurgeon. The author's experience and opinions, as well as qualitative data, were analyzed. A comparison was made on image quality, illumination, field of view, and magnification of the operative field and ergonomics.

RESULTS

Seven out of 9 cranial pediatric cases were switched from VITOM 2D to operative microscope due to low-image definition in depth of cranial cavity. Poor visualization of bleeding source in surgical field was another major drawback. Two cranial cases in which exoscope were used exclusively, included superficial tumors. In all 5 spinal cases, VITOM 2D was successfully used without any major difficulty. The exoscope's advantages were observed in ergonomics and ease in switching to naked eyes, but the microscope's field of view, illumination, magnification, and user-friendliness was considered superior.

CONCLUSION

2D-VITOM is best suited for spinal and superficial cranial tumors. However, a lot of modifications are to be done especially in optics to become a substitute for operative microscope.

Expanding Access to Microneurosurgery in Low-Resource Settings: Feasibility of a Low-Cost Exoscope in Transforaminal Lumbar Interbody Fusion

Objectives Less than a quarter of the world population has access to microneurosurgical care within a range of 2 hours. We introduce a simplified exoscopic visualization system to achieve optical magnification, illumination, and video recording in low-resource settings.

Materials and Methods We purchased a 48 megapixels industrial microscope camera with a heavy-duty support arm, a wide field c-mount lens, and an LED ring light at a total cost of US$ 125. Sixteen patients with lumbar degenerative disk disease were divided into an exoscope group and a conventional microscope group. In each group we performed four open and four minimally invasive transforaminal lumbar interbody fusion procedures. We further conducted a questionnaire-based assessment of the user experience.

Results The overall user experience was positive. The exoscope achieved similar postoperative improvement with comparable blood loss and operating time as the conventional microscope. It provided a similar image quality, magnification and illumination. Yet, the lack of stereoscopic perception and the cumbersome adjustability of the camera position and angle resulted in a shallow learning curve. Most users strongly agreed that the exoscope would significantly improve surgical teaching. Over 75% reported they would recommend the exoscope to colleagues and all users saw its great potential for low-resource environments.

Conclusion Our low-budget exoscope is technically non-inferior to the conventional binocular microscope and purchasable at a significantly lower price. It may thus help expand access to neurosurgical care and training worldwide.

Comparative Learning Curves of Microscope Versus Exoscope: A Preclinical Randomized Crossover Noninferiority Study

Background

An exoscope heralds a new era of optics in surgery. However, there is limited quantitative evidence describing and comparing the learning curve.

Objectives

This study aimed to investigate the learning curve, plateau, and rate of novice surgeons using an Olympus ORBEYE exoscope compared to an operating microscope (Carl Zeiss OPMI PENTERO or KINEVO 900).

Methods

A preclinical, randomized, crossover, noninferiority trial assessed the performance of seventeen novice and seven expert surgeons completing the microsurgical grape dissection task “Star’s the limit.” A standardized star was drawn on a grape using a stencil with a 5 mm edge length. Participants cut the star and peeled the star-shaped skin off the grape with microscissors and forceps while minimizing damage to the grape flesh. Participants repeated the task 20 times consecutively for each optical device. Learning was assessed using model functions such as the Weibull function, and the cognitive workload was assessed with the NASA Task Load Index (NASA-TLX).

Results

Seventeen novice (male:female 12:5; median years of training 0.4 [0–2.8 years]) and six expert (male:female 4:2; median years of training 10 [8.9–24 years]) surgeons were recruited. “Star’s the limit” was validated using a performance score that gave a threshold of expert performance of 70 (0–100). The learning rate (ORBEYE −0.94 ± 0.37; microscope −1.30 ± 0.46) and learning plateau (ORBEYE 64.89 ± 8.81; microscope 65.93 ± 9.44) of the ORBEYE were significantly noninferior compared to those of the microscope group (p = 0.009; p = 0.027, respectively). The cognitive workload on NASA-TLX was higher for the ORBEYE. Novices preferred the freedom of movement and ergonomics of the ORBEYE but preferred the visualization of the microscope.

Conclusions

This is the first study to quantify the ORBEYE learning curve and the first randomized controlled trial to compare the ORBEYE learning curve to that of the microscope. The plateau performance and learning rate of the ORBEYE are significantly noninferior to those of the microscope in a preclinical grape dissection task. This study also supports the ergonomics of the ORBEYE as reported in preliminary observational studies and highlights visualization as a focus for further development.

Use of the 3D exoscope for the supracerebellar infratentorial approach in the concorde position: an effective and ergonomic alternative. Illustrative cases

BACKGROUND

The supracerebellar infratentorial approach provides wide flexibility as a far-reaching corridor to the pineal region, posterior third ventricle, posterior medial temporal lobe, posterolateral mesencephalon, quadrigeminal cistern, and thalamus. Traditionally, the patient is placed in the sitting position, allowing gravity retraction on the cerebellum to widen the supracerebellar operative corridor beneath the tentorium. What this approach gains in anatomical orientation it lacks in surgeon ergonomics, as the sitting position presents technical challenges, forces the surgeon to adopt to an uncomfortable posture while performing the microsurgical dissection/tumor resection under the microscope, and is also associated with an increased risk of venous air embolism.

OBSERVATIONS

In this article, the authors present the use of the three-dimensional (3D) exoscope with a standard prone Concorde position as an alternative for the treatment of lesions requiring a supracerebellar infratentorial approach for lesions in the pineal region, posterior third ventricle, and the superior surface of the cerebellar vermis. The authors present four illustrative cases (one pineal cyst, one ependymoma, and two cerebellar metastases) in which this approach provided excellent intraoperative visualization and resulted in good postoperative results. A step-by-step description of our surgical technique is reviewed in detail.

LESSONS

The use of the 3D exoscope with the patient in the prone Concorde position is an effective and ergonomically favorable alternative to the traditional sitting position for the treatment of lesions requiring a supracerebellar infratentorial approach. This technique allows improved visualization of deep structures, with a possible decreased risk of potential complications.

A Three-Surgeon–Six-Hand Operation Using a 4K-3D Exoscope for Neurological Surgery: A Case Report

Background

Advances in digital imaging including evolving of 3-dimensional (3D) exoscope has allowed its use as an alternative to microscopes in neurosurgery. The exoscope can concede wide space around the operating table and patient. Here, we show a three-surgeon–six-hand operative approach using a 4K-3D exoscope. Practical advantages and disadvantages of this approach are discussed.

Clinical Presentation

A 58-year-old male was refered with a 60 mm diameter meningioma in the right frontal convexity. The tumor removal was done by an operator and two assistants with a scrub nurse while viewing images displayed on a 55-inch monitor with integrated 4K and 3D visualization technology retrieved by KINEVO®. Meaningful communication between the operator and two assistants allowed for simultaneous, and precise surgical procedures. Gross total removal was achieved without damaging the brain.

Conclusion

The ocular-free, openness of 4K-3D exoscope allows for a three-surgeon–six-handed operation, which leads to simultaneous surgical maneuvers by multiple hands, shorter operative time, flexible/intermittent brain retraction made by two assistants, and educational benefits owing to the surgical procedure being visually shared.

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.

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.

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.

Impact of different visualization devices on accuracy, efficiency, and dexterity in neurosurgery: a laboratory investigation

OBJECTIVE

Extracorporeal telescopes (exoscopes) have been the latest addition to the neurosurgeons' armamentarium, acting as a bridge between operating microscopes and endoscopes. However, to the authors' knowledge there are no published preclinical laboratory studies of the accuracy, efficiency, and dexterity of neurosurgical training for the use of 2D or 3D exoscopes compared with microscopes.

METHODS

In a controlled experimental setup, 22 participating neurosurgery residents performed simple (2D) and complex (3D) motor tasks with three visualization tools in alternating sequence: a 2D exoscope, 3D exoscope, and microscope, using a block randomization model based on the neurosurgeons' prior training experience (novice, intermediate, and senior: n = 6, 12, and 4, respectively). Performance scores (PS; including error and efficiency scores) and dexterity scores (DS) were calculated to objectify the accuracy, efficiency, and finesse of task performance. Repeated measures ANOVA analysis was used to compare the PS, DS, and cumulative scores (CS) of candidates using the three visualization aids. Bland-Altman plots and intraclass correlation coefficients were generated to quantify intraobserver and interobserver agreement for DS. Subgroup analysis was performed to assess the impact of participants' prior training. A postexercise survey was conducted to assess the comfort level (on a 10-point analog scale) of the participants while using each visualization tool for performing the suturing task.

RESULTS

PS, DS, and CS were significantly impacted by the visualization tool utilized for 2D motor tasks (p < 0.001 for each), with the microscope faring better than the 2D exoscope (p = 0.04) or 3D exoscope (p = 0.008). The PS for the 3D object transfer task was significantly influenced by the visualization aid used (p = 0.007), with the microscope and 3D exoscope faring better than the 2D exoscope (p = 0.04 for both). The visualization instrument used significantly affected the DS and CS for the suturing task (p < 0.001 for both), with the microscope again scoring better than the 2D exoscope (p < 0.001) or 3D exoscope (p = 0.005). The impact of the visualization aid was more apparent in participants with a shorter duration of residency (novice, p = 0.03; intermediate, p = 0.0004). Participants also felt the greatest operational comfort while working with a microscope, 3D exoscope, and 2D exoscope, in that order (p < 0.0001).

CONCLUSIONS

Compared with 3D and 2D exoscopes, an operating microscope provides better dexterity and performance and a greater operational comfort level for neurosurgeons while they are performing 2D or 3D motor tasks. For performing complex 3D motor tasks, 3D exoscopes offer selective advantages in dexterity, performance, and operational comfort level over 2D exoscopes. The relative impact of visualization aids on surgical proficiency gradually weakens as the participants' residency duration increases.