Incorporating New Technologies to Overcome the Limitations of Endoscopic Spine Surgery: Navigation, Robotics, and Visualization

Advances and Challenges of Endoscopic Spine Surgery

The purpose of this paper is to review the data supporting current endoscopic surgical techniques for the spine and the potential challenges and future of the field. The origins of endoscopic spine surgery can be traced back many decades, with many important innovations throughout its development. It can be applied to all levels of the spine, with many robust trials supporting its clinical outcomes. Continued clinical research is needed to explore its expanding indications. Although the limitations of starting an endoscopic program can be justified by its cost effectiveness and positive societal impact, challenges facing its widespread adoption are still present. As more residency and fellowship programs include endoscopy as part of their spine training, it will become more prevalent in hospitals in the United States. Technological advancements in spine surgery will further propel and enhance endoscopic techniques as they become an integral part of a spine surgeon's repertoire.

Applications of navigation in full-endoscopic spine surgery

PURPOSE

Advancement in all surgery continues to progress towards more minimally invasive surgical (MIS) approaches. One of the platform technologies which has helped drive this trend within spine surgery is the development of endoscopy; however, the limited anatomic view experienced when performing endoscopic spine surgery requires a significant learning curve. The use of intraoperative navigation has been adapted for endoscopic spine surgery, as this provides computer-reconstructed visual data presented in three dimensions, which can increase feasibility of this technique to more surgeons.

METHODS

This paper will describe the principles, technical considerations, and applications of stereotactic navigation-guided endoscopic spine surgery.

RESULTS

Full-endoscopic spine surgery has advanced in recent years such that it can be utilized in both decompressive and fusion surgeries. One of the major pitfalls to any minimally invasive surgery (including endoscopic) is that the limited surgical view can often complicate the surgery or confuse the surgeon, leading to longer operative times, higher risks, among others. This is the real utility to using navigation in conjunction with the endoscope-when registered correctly and utilized appropriately, navigated endoscopic spine surgery can take some of the guesswork out of the minimally invasive approach.

CONCLUSIONS

Using navigation with endoscopy in spine surgery can potentially expand this technique to surgeons who have yet to master endoscopy as the assistance provided by the navigation can alleviate some of the complexities with anatomic understanding and surgical planning.

MicroRNA-29a Mitigates Laminectomy-Induced Spinal Epidural Fibrosis and Gait Dysregulation by Repressing TGF-β1 and IL-6

Spinal epidural fibrosis is one of the typical features attributable to failed back surgery syndrome, with excessive scar development in the dura and nerve roots. The microRNA-29 family (miR-29s) has been found to act as a fibrogenesis-inhibitory factor that reduces fibrotic matrix overproduction in various tissues. However, the mechanistic basis of miRNA-29a underlying the overabundant fibrotic matrix synthesis in spinal epidural scars post-laminectomy remained elusive. This study revealed that miR-29a attenuated lumbar laminectomy-induced fibrogenic activity, and epidural fibrotic matrix formation was significantly lessened in the transgenic mice (miR-29aTg) as compared with wild-type mice (WT). Moreover, miR-29aTg limits laminectomy-induced damage and has also been demonstrated to detect walking patterns, footprint distribution, and moving activity. Immunohistochemistry staining of epidural tissue showed that miR-29aTg was a remarkably weak signal of IL-6, TGF-β1, and DNA methyltransferase marker, Dnmt3b, compared to the wild-type mice. Taken together, these results have further strengthened the evidence that miR-29a epigenetic regulation reduces fibrotic matrix formation and spinal epidural fibrotic activity in surgery scars to preserve the integrity of the spinal cord core. This study elucidates and highlights the molecular mechanisms that reduce the incidence of spinal epidural fibrosis, eliminating the risk of gait abnormalities and pain associated with laminectomy.

The Role and Future of Endoscopic Spine Surgery: A Narrative Review

Many types of surgeries are changing from conventional to minimally invasive techniques. Techniques in spine surgery have also changed, with endoscopic spine surgery (ESS) becoming a major surgical technique. Although ESS has advantages such as less soft tissue dissection and normal structure damage, reduced blood loss, less epidural scarring, reduced hospital stay, and earlier functional recovery, it is not possible to replace all spine surgery techniques with ESS. ESS was first used for discectomy in the lumbar spine, but the range of ESS has expanded to cover the entire spine, including the cervical and thoracic spine. With improvements in ESS instruments (optics, endoscope, endoscopic drill and shaver, irrigation pump, and multiportal endoscopic), limitations of ESS have gradually decreased, and it is possible to apply ESS to more spine pathologies. ESS currently incorporates new technologies, such as navigation, augmented and virtual reality, robotics, and 3-dimentional and ultraresolution visualization, to innovate and improve outcomes. In this article, we review the history and current status of ESS, and discuss future goals and possibilities for ESS through comparisons with conventional surgical techniques.

Training to be a spinal endoscopic surgeon: What matters?

Objective

Spinal endoscopic surgery has been promoted rapidly in the past decade, attracting an increasing number of young, dedicated surgeons. However, it has long been denounced for its long learning curve as a factor impeding the development of this state-of-the-art technique. The aim of the present study was to discover what really matters in the educational process of becoming a spinal endoscopic surgeon.

Methods

An online survey consisting of 14 compulsory questions was distributed in April and May 2022 through the First Chinese Spinal Endoscopic Surgeons Skills Competition. Reminders were sent to increase response rates.

Results

Of the 893 emails that were sent, we received 637 responses. A total of 375 (76.7%) surgeons most frequently used endoscopic techniques in their practices. Regardless of their different backgrounds, 284 (75.7%) surgeons thought it would be necessary for a young spinal endoscopic surgeon to perform 300 cases independently in order to become proficient, followed by 500 (n=43, 11.5%), 100 (n=40, 10.7%), and 1,000 (n=8, 2.1%) cases. According to the surgeons, the most difficult aspect of mastering the endoscopic technique is a disparate surgical view (n=255, 68%), followed by adaption to new instruments (n=86, 22.9%) and hand-eye coordination (n=34, 9.1%). The most helpful training method for helping the spinal endoscopic surgeons of younger generations improve is operating on simulation models or cadaver courses (n=216, 57.6%), followed by online or offline theoretical courses (n=67, 17.9%), acquiring opportunities during surgeries (n=51, 13.6%), and frequently participating in surgeries as an assistant (n=41, 10.9%).

Conclusion

From the perspective of surgeons, to be skilled in spinal endoscopic surgery means overcoming a steep learning curve. However, training systems should be given more attention to make them more accessible to younger surgeons so they can work on simulation models or take cadaver courses.

Transforaminal endoscopic lumbar discectomy with targeted puncture and foraminotomy for very highly migrated disc herniation: A technique note with case series

Background

Transforaminal endoscopic lumbar discectomy (TELD) has been widely used for lumbar disc herniation. However, in some challenging cases such as very highly migrated disc herniation (VHMDH), traditional TELD is difficult to access the pathology.

Methods

From January 2016 to December 2019, 63 patients with single-level VHMDH underwent TELD using targeted puncture and foraminotomy techniques were included. All patients were followed up for 26.5 months on average (range, 24–48 months). Operative time, length of hospital stay, visual analog scale (VAS) score, Oswestry Disability Index (ODI), modified MacNab criteria and surgical complications were evaluated.

Results

The operative time was 40–120 min (56.8 on average). The length of hospitalization was 2.5 days (range, 2–4 d). VAS score decreased significantly from 5.5 ± 1.3 preoperatively to 1.9 ± 1.30 (p < 0.001) 1 day postoperatively, and to 0.9 ± 0.8 (p < 0.001) at the final follow-up. ODI score improved significantly from 23.5 ± 3.2 preoperatively to 13.4 ± 3.0 (p < 0.001) 1 day postoperatively; and 3.1 ± 1.2 (p < 0.001) at the final follow-up. According to the modified MacNab criteria, 40 patients (63.5%) showed excellent results, 20 patients (31.7%) were rated as good, 2 patients (3.2%) were rated as fine, and 1 patient (1.6%) was rated as bad at the final follow-up. No residual fragments, nerve root or cauda equina injury was shown in this series. One recurrent case was resolved by open surgery.

Conclusions

With modified targeted puncture and foraminotomy techniques, VHMDH can be accessed safely and effectively, and satisfactory clinical outcomes can be obtained for these patients.

Navigation Techniques in Endoscopic Spine Surgery

Endoscopic spine surgery (ESS) advances the principles of minimally invasive surgery, including minor collateral tissue damage, reduced blood loss, and faster recovery times. ESS allows for direct access to the spine through small incisions and direct visualization of spinal pathology via an endoscope. While this technique has many applications, there is a steep learning curve when adopting ESS into a surgeon's practice. Two types of navigation, optical and electromagnetic, may allow for widespread utilization of ESS by engendering improved orientation to surgical anatomy and reduced complication rates. The present review discusses these two available navigation technologies and their application in endoscopic procedures by providing case examples. Furthermore, we report on the future directions of navigation within the discipline of ESS.

Robotic Spine Surgery: Past, Present, and Future

STUDY DESIGN

Systematic review.

OBJECTIVE

The aim of this review is to present an overview of robotic spine surgery (RSS) including its history, applications, limitations, and future directions.

SUMMARY OF BACKGROUND DATA

The first RSS platform received United States Food and Drug Administration approval in 2004. Since then, robotic-assisted placement of thoracolumbar pedicle screws has been extensively studied. More recently, expanded applications of RSS have been introduced and evaluated.

METHODS

A systematic search of the Cochrane, OVID-MEDLINE, and PubMed databases was performed for articles relevant to robotic spine surgery. Institutional review board approval was not needed.

RESULTS

The placement of thoracolumbar pedicle screws using RSS is safe and accurate and results in reduced radiation exposure for the surgeon and surgical team. Barriers to utilization exist including learning curve and large capital costs. Additional applications involving minimally invasive techniques, cervical pedicle screws, and deformity correction have emerged.

CONCLUSION

Interest in RSS continues to grow as the applications advance in parallel with image guidance systems and minimally invasive techniques.

IRB APPROVAL

N/A.

[Clinical study on real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion]

OBJECTIVE

To analyze the technical notes, effectiveness, and current issues of real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion.

METHODS

Between April 2020 and October 2021, a total of 27 patients received real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion. There were 18 males and 9 females with an average age of 63.2 years (range, 48-84 years). There were 6 cases of lumbar spinal stenosis, 1 case of lumbar instability, 9 cases of lumbar spinal stenosis with instability, 3 cases of degenerative spondylolisthesis, 6 cases of isthmus spondylolisthesis, and 2 cases of recurrent lumbar disc herniation. All patients showed neurological symptoms before operation (ipsilateral symptom for 15 cases and bilateral symptom for 12 cases). The symptom duration was 1-300 months (median, 24 months). The operations were performed via transforaminal approach in 8 cases, trans-facet joint approach in 18 cases, and combined approaches in 1 case. A total of 32 levels were fused, including 23 single-level cases, 3 two-level cases, and 1 three-level case. Lumbar fusion segment was L _{2, 3} in 1 case, L _{3, 4} in 4 cases, L _{4, 5} in 20 cases, and L ₅, S ₁ in 7 cases. The operation time, intraoperative estimated blood loss (IEBL), and perioperative complications were recorded. The improvement of intervertebral space height at fusion level was measured, and the accuracy of percutaneous pedicle screw (PPS) and Cage placement was also evaluated based on CT images performed at 1 week postoperatively. Visual analogue scale (VAS) score for both low back pain and leg pain, Japanese Orthopaedic Association (JOA) score, and Oswestry disability index (ODI) were evaluated before operation, at 1 week postoperatively, and at last follow-up. Satisfaction to effectivenss were assessed by patients using modified MacNab criteria at last follow-up.

RESULTS

The operation time was ranged from 255 to 805 minutes (mean, 424.9 minutes). IEBL was 150-290 mL (mean, 219.3 mL). All patients received follow-up with the duration from 4 to 22 months (mean, 12.4 months). At 1 week postoperatively and last follow-up, VAS scores of low back pain and leg pain, JOA score, and ODI were significantly improved when compared with those before operation ( P<0.05). At last follow-up, the clinical indicators were similar in comparison with those at 1 week postoperatively ( P>0.05). There were 26 patients and 1 patient who respectively ranked excellent and mild in terms of effectiveness according to the modified MacNab criteria, with the excellent and good rate of 96.3%. There was 1 patient who suffered from incomplete injury of L ₅ nerve root and partial neurological function recovered after 3-month conservative treatments. There were 118 implanted PPSs, and 116 of them were implanted under navigation. There were 33 Cages that were implanted under navigation. The accuracy of PPS and Cage placement was 99.1% and 97.0% respectively based on CT performed at 1 week postoperatively. The postoperative intervertebral space height was significantly increased in comparison with that before operation ( P<0.05). During follow-up, mild Cage subsidence was observed in 1 patient, whereas no fixation loosing was found.

CONCLUSION

Real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion has great safety and effectiveness with satisfactory preliminary clinical results. Design and further improvement of surgical equipment and instruments are expected to resolve the current technical difficulties.

Multimodal Intraoperative Image-Driven Surgery for Skull Base Chordomas and Chondrosarcomas

Given the difficulty and importance of achieving maximal resection in chordomas and chondrosarcomas, all available tools offered by modern neurosurgery are to be deployed for planning and resection of these complex lesions. As demonstrated by the review of our series of skull base chordoma and chondrosarcoma resections in the Advanced Multimodality Image-Guided Operating (AMIGO) suite, as well as by the recently published literature, we describe the use of advanced multimodality intraoperative imaging and neuronavigation as pivotal to successful radical resection of these skull base lesions while preventing and managing eventual complications.