Educational value of a high-definition three-dimensional extracorporeal telescope (exoscope) in lateral access spine surgery

Introduction

Lateral lumbar interbody fusion (LLIF) has gained popularity as a highly effective minimally invasive surgical option for patients afflicted with degenerative lumbar conditions (1). The lateral access to the spine avoids posterior neural elements while providing surgeons with optimal views of the disc space (2). It also facilitates the implantation of larger fusion cages which has been demonstrated to be associated with superior radiological and clinical outcomes (3,4). Furthermore, familiarity with the lateral approach enhances a spine surgeon’s repertoire for the treatment of a variety of conditions ranging from severe burst fractures to pyogenic spondylodiscitis (5,6). However, learning a new minimally invasive approach to the spine poses significant challenges (7,8). Surgical trainees and assistants often struggle to visualize the procedure from the surgeon’s perspective, which may potentially hinder their full learning experience.

In recent years, the use of a high-definition three-dimensional extracorporeal telescope (exoscope) during spine surgeries has been gaining traction (9,10). Although previous studies have highlighted the educational benefits of using an exoscope in surgery (11,12), research specifically addressing its educational values in lateral access spine surgery remains scarce. Therefore, this study aimed to assess the educational benefits of using an exoscope for junior surgical doctors (JSDs) and scrub nurses (ScNs) during LLIF procedures. We present this article in accordance with the SURGE reporting checklist (available at https://jss.amegroups.com/article/view/10.21037/jss-24-123/rc).

Methods

Operative setup

The Modus V™ exoscope (Synaptive Medical, Toronto, Ontario, Canada) was deployed in all cases. With the patient starting in a lateral position, the surgeon stands at the abdominal side of the patient while the JSD stands on the opposite side. This is the standard position for the surgical assistant. Two viewing monitors were set up at opposite ends such that both the surgeon and JSD can view the surgical field with optimal ergonomics. The layout of the operating theatre (OT) was standardized for all cases. This can be seen in Figure 1.

Figure 1 Operating theatre layout. This image is published with the participants’ consent.

Survey

This survey was conducted in Changi General Hospital, Singapore. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). As no patient outcomes or details were evaluated, ethics approval was not required. Informed consent was obtained from all participants. Consent was also obtained from all individuals present in photographs published in this article.

All JSDs and ScNs working in the Department of Orthopedic Surgery and Department of Neurosurgery at Changi General Hospital, Singapore between January 2024 to July 2024 were invited for the survey by one of the authors (Y.Y.T.). JSDs and ScNs included in this study had to have participated in LLIF cases with and without the usage of an exoscope. No incentive was given for participation in the survey. Once identified, JSDs and ScNs then answered a set of standardized questions in relation to their learning experience via an online interface (Google Forms). The survey questions can be found in Table 1. These questions were collectively devised by the authors with the purpose of evaluating the learning experience of JSDs during LLIF procedures.

Statistical analysis

The results were summarized with descriptive statistics, with scores reported as median with interquartile range (IQR).

Results

A total of 12 JSDs (n=6) and ScNs (n=6) were included in the study. The response rate was 100%. They reported enhanced visualisation of anatomy during both superficial dissection [median score =4.5 (IQR, 4–5)] and deep dissection [median score =5 (IQR, 5–5)]. Similar ratings were given for understanding disc space anatomy [median score =5 (IQR, 5–5)] and overall appreciation of the surgery [median score =5 (IQR, 4.25–5)]. Participants found the exoscope to be more ergonomic for visualizing the surgery [median score =5 (IQR 4–5)] and noted significant knowledge improvement in LLIF procedures [median score =5 (IQR, 4–5)]. They expressed a strong preference for its use in future LLIF cases [median score =5 (IQR, 4.25–5)]. The results are summarized in Table 2.

Discussion

As lateral access surgery becomes increasingly popular, it is essential for surgical assistants and future spine surgeons to be familiar with this approach. However, the minimally invasive nature of the procedure presents challenges for traditional educational methods, which may not adequately provide live visualization during surgery. To address this, the authors utilised a high-definition digital imaging system to enhance the educational experience for surgical assistants and improve overall training outcomes. To our knowledge, this is the first study to report on the educational experiences of surgical assistants involved in LLIF surgeries using an exoscope.

Enhanced visualization and appreciation of surgical anatomy

The lateral approach to the spine involves anatomical regions that may be unfamiliar to most junior surgeons. Deeper structures, such as the peritoneum, genitofemoral nerve, and iliac vessels, can be difficult to visualize during dissection. Although the surgeon may pause to highlight important structures, surgical assistants may still struggle to fully appreciate the intricate techniques required to avoid injury to these delicate structures. In this study, surgical assistants reported significantly improved visualization of surgical anatomy, particularly during deep dissection, when using the exoscope. Figure 2 illustrates the exoscope’s view during deep dissection, showing the genitofemoral nerve overlaying the psoas muscle, while Figure 3 demonstrates the disc space and incision made for annulotomy. The educational benefits of using the exoscope in other settings, such as in otologic surgery, has been previously described (12).

Figure 2 Exoscope view of surgical site with genitofemoral nerve labelled.

Figure 3 Exoscope view of surgical site demonstrating annulus fibrosus.

Workflow and ergonomics

The use of an exoscope also enables ScNs to follow the surgery more closely, allowing them to prepare necessary equipment more efficiently, potentially improving workflow and reducing operating time. The ability to predict and prepare equipment in advance has been reported to improve workflow in other surgical specialties (13,14). Furthermore, in LLIF procedures, the assistant is required to be on the lumbar side of the patient during specific steps, such as mounting the tubular retractor bracket and providing counterforce when the surgeon inserts both trial and actual fusion cages. Without the exoscope, the assistant would need to move from one side of the patient to the other, increasing the risk of contamination. The use of the exoscope in LLIF cases allows the assistant to be more effective in their role.

Additionally, the exoscope enhances ergonomics for surgical assistants by projecting a magnified, high-definition view of the surgical site on a screen, allowing them to observe the procedure while maintaining a neutral neck position, as illustrated in Figure 4. This ergonomic benefit has also been previously reported in oblique lateral interbody fusion (OLIF) procedures employing the use of an exoscope (10). While the exoscope offers improved ergonomics for the assisting surgeon, it may come at the expense of the main surgeon’s comfort. As shown in Figure 4, the main surgeon had to tilt his neck slightly to avoid the exoscope and view the monitor, which could lead to significant neck discomfort if maintained for prolonged periods. Another disadvantage of the exoscope is that it occupies extra space in the operating theater, potentially making the environment more cramped, as seen in Figure 1. This crowding may increase the risk of contamination.

Figure 4 Close-up of surgeon and surgical assistant positions. This image is published with the participants’ consent.

Comparison with other imaging systems

Before the advent of exoscopes, the operative microscope (OM) was the preferred tool for projecting the surgical field onto external monitors to appreciate fine anatomical details. However, the OM’s shorter focal length limited the use of longer instruments, and it was impractical to move the microscope in and out of the surgical field during surgery. In contrast, the exoscope features a longer focal length, allowing it to be positioned further from the surgical field while still producing high-definition images. This provides surgeons with more space for instruments and greater freedom of movement. Additionally, the exoscope offers a three-dimensional function, enhancing trainees’ ability to appreciate the depth of the surgical site. Previous studies have compared the OM and exoscope (9,15), concluding that the exoscope conferred multiple advantages compared to the OM.

Another option for improving visualization of surgical anatomy includes the Viseon MaxView^® 4K Lateral portable camera system. This single-use camera system mounts to the proximal aspect of retractors used in lateral access procedures and has been reported to be able to deliver high-definition images (16). Given the significantly smaller form, it overcomes the potential disadvantages related to the size of the exoscope as highlighted above. However, as a single-use device, it may not be as environmentally friendly as the exoscope. There are also no studies comparing the image quality of the Viseon MaxView^® 4K camera system to that of an exoscope. Such studies may be worthwhile in the future.

Surgical video recording and knowledge sharing

Using the exoscope not only provides high-definition images during surgery but also enables the recording of the entire procedure. This recorded footage can be invaluable for educating surgical residents (17) and can be shared with other surgeons, particularly as interest in LLIF procedures grows (1). Sharing high-quality, well-edited recordings with the surgical community can contribute to the ongoing development and refinement of surgical techniques. Another advantage of using the exoscope during surgery at our institution is that the videos can be shared with our advanced nurse practitioners specializing in spine surgery, enhancing their understanding of the procedure. This deeper insight enables them to be more effective in their crucial roles (18) in pre-operative counseling and post-operative follow-up for patients undergoing LLIF.

Strengths and limitations

This survey was conducted in a single-centre and the operative set-up was standardized across all cases. This lends strength to the reliability of the study. However, the authors acknowledge that the small sample size limits external validity. In addition, as this was a survey of the department’s members, there is a risk of social desirability bias.

Conclusions

In conclusion, the exoscope is a valuable asset for lateral access spinal procedures, enhancing the educational experience for JSDs and ScNs. It also has the potential to improve workflow and catalyse advancements in surgical techniques. However, further research is required to evaluate and compare the various imaging systems available.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the SURGE reporting checklist. Available at https://jss.amegroups.com/article/view/10.21037/jss-24-123/rc

Data Sharing Statement: Available at https://jss.amegroups.com/article/view/10.21037/jss-24-123/dss

Peer Review File: Available at https://jss.amegroups.com/article/view/10.21037/jss-24-123/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-123/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). As no patient outcomes or details were evaluated, ethics approval was not required. Informed consent was obtained from all participants. Consent was also obtained from all individuals present in photographs published in this article.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Zhang JY, Ezzat B, Coenen RJJ, et al. Bibliometric and trend analysis of the top 100 most-cited articles on lateral interbody fusion (LIF). Neurosurg Rev 2024;47:245. [Crossref] [PubMed]
2. Salzmann SN, Shue J, Hughes AP. Lateral Lumbar Interbody Fusion-Outcomes and Complications. Curr Rev Musculoskelet Med 2017;10:539-46. [Crossref] [PubMed]
3. Zhu HF, Fang XQ, Zhao FD, et al. Comparison of Oblique Lateral Interbody Fusion (OLIF) and Minimally Invasive Transforaminal Lumbar Interbody Fusion (MI-TLIF) for Treatment of Lumbar Degeneration Disease: A Prospective Cohort Study. Spine (Phila Pa 1976) 2022;47:E233-42. [Crossref] [PubMed]
4. Sato J, Ohtori S, Orita S, et al. Radiographic evaluation of indirect decompression of mini-open anterior retroperitoneal lumbar interbody fusion: oblique lateral interbody fusion for degenerated lumbar spondylolisthesis. Eur Spine J 2017;26:671-8. [Crossref] [PubMed]
5. Tani Y, Saito T, Taniguchi S, et al. A New Treatment Algorithm That Incorporates Minimally Invasive Surgery for Pyogenic Spondylodiscitis in the Thoracic and Lumbar Spines: The Results of Its Clinical Application to a Series of 34 Patients. Medicina (Kaunas) 2022;58:478. [Crossref] [PubMed]
6. Podet AG, Morrow KD, Robichaux JM, et al. Minimally invasive lateral corpectomy for thoracolumbar traumatic burst fractures. Neurosurg Focus 2020;49:E12. [Crossref] [PubMed]
7. Liu C, Wang J. Learning Curve of Minimally Invasive Surgery Oblique Lumbar Interbody Fusion for Degenerative Lumbar Diseases. World Neurosurg 2018;120:e88-93. [Crossref] [PubMed]
8. Warren SI, Wadhwa H, Koltsov JCB, et al. One surgeon's learning curve with single position lateral lumbar interbody fusion: perioperative outcomes and complications. J Spine Surg 2021;7:162-9. [Crossref] [PubMed]
9. Teo THL, Tan BJ, Loo WL, et al. Utility of a high-definition 3D digital exoscope for spinal surgery during the COVID-19 pandemic. Bone Jt Open 2020;1:359-63. [Crossref] [PubMed]
10. Ariffin MHM, Ibrahim K, Baharudin A, et al. Early Experience, Setup, Learning Curve, Benefits, and Complications Associated with Exoscope and Three-Dimensional 4K Hybrid Digital Visualizations in Minimally Invasive Spine Surgery. Asian Spine J 2020;14:59-65. [Crossref] [PubMed]
11. Nossek E, Schneider JR, Kwan K, et al. Technical Aspects and Operative Nuances Using a High-Definition 3-Dimensional Exoscope for Cerebral Bypass Surgery. Oper Neurosurg (Hagerstown) 2019;17:157-63. [Crossref] [PubMed]
12. Tu NC, Doerfer K, Costeloe A, et al. Educational Benefit of the Three-Dimensional Exoscope Versus Operating Microscope in Otologic Surgery. Otol Neurotol 2024;45:150-3. [Crossref] [PubMed]
13. Wagner L, Jourdan S, Mayer L, et al. Robotic scrub nurse to anticipate surgical instruments based on real-time laparoscopic video analysis. Commun Med (Lond) 2024;4:156. [Crossref] [PubMed]
14. Mitchell L, Flin R, Yule S, et al. Thinking ahead of the surgeon. An interview study to identify scrub nurses' non-technical skills. Int J Nurs Stud 2011;48:818-28. [Crossref] [PubMed]
15. Iqbal J, Covell MM, Jabeen S, et al. Comparative analysis of exoscope-assisted spine surgery versus operating microscope: A systematic review. World Neurosurg X 2024;21:100258. [Crossref] [PubMed]
16. Balogun SA, Sommer F, Waterkeyn F, et al. Feasibility of High-Fidelity Simulator Models for Minimally Invasive Spine Surgery in a Resource-Limited Setting: Experience From East Africa. J Am Acad Orthop Surg Glob Res Rev 2023;7:e23.00038.
17. Ibrahim AM, Varban OA, Dimick JB. Novel Uses of Video to Accelerate the Surgical Learning Curve. J Laparoendosc Adv Surg Tech A 2016;26:240-2. [Crossref] [PubMed]
18. Sarro A, Rampersaud YR, Lewis S. Nurse practitioner-led surgical spine consultation clinic. J Adv Nurs 2010;66:2671-6. [Crossref] [PubMed]