Augmented Reality to Improve Surgical Workflow in Minimally Invasive Transforaminal Lumbar Interbody Fusion – A Feasibility Study With Case Series

Objective Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a highly reproducible procedure for the fusion of spinal segments. We recently introduced the concept of “total navigation” to improve workflow and eliminate fluoroscopy. Image-guided surgery incorporating augmented reality (AR) may further facilitate workflow. In this study, we developed and evaluated a protocol to integrate AR into the workflow of MIS-TLIF. Methods A case series of 10 patients was the basis for the evaluation of a protocol to facilitate tubular MIS-TLIF by the application of AR. Surgical TLIF landmarks were marked on a preoperative computed tomography (CT)-scan using dedicated software. This marked CT scan was fused intraoperatively with the low-dose navigation CT scan using elastic image fusion, and the markers were transferred to the intraoperative scan. Our experience with this workflow and the surgical outcomes were collected. Results Our AR protocol was safely implemented in all cases. The TLIF landmarks could be preoperatively planned and transferred to the intraoperative imaging. Of the 10 cases, 1 case had additionally a synovial cyst resection and in 2 cases an additional bony decompression was performed due to central stenosis. The average procedure time was 160.6±31.9 minutes. The AR implementation added 1.72±0.37 minutes to the overall procedure time. No complications occurred. Conclusion Our findings support the idea that total navigation with AR may further facilitate the workflow, especially in cases with more complex anatomy and for teaching and training purposes. More work is needed to simplify the software and make AR integration more user-friendly

Intraoperative image guidance for cervical spine surgery

Intraoperative image-guidance in spinal surgery has been influenced by various technological developments in imaging science since the early 1990s. The technology has evolved from simple fluoroscopic-based guidance to state-of-art intraoperative computed tomography (iCT)-based navigation systems. Although the intraoperative navigation is more commonly used in thoracolumbar spine surgery, this newer imaging platform has rapidly gained popularity in cervical approaches. The purpose of this manuscript is to address the applications of advanced image-guidance in cervical spine surgery and to describe the use of intraoperative neuro-navigation in surgical planning and execution. In this review, we aim to cover the following surgical techniques: anterior cervical approaches, atlanto-axial fixation, subaxial instrumentation, percutaneous interfacet cage implantation as well as minimally invasive posterior cervical foraminotomy (PCF) and unilateral laminotomy for bilateral decompression. The currently available data suggested that the use of 3D navigation significantly reduces the screw malposition, operative time, mean blood loss, radiation exposure, and complication rates in comparison to the conventional fluoroscopic-guidance. With the advancements in technology and surgical techniques, 3D navigation has potential to replace conventional fluoroscopy completely

79 Flexible Support Materials Maintain Disc Height and Support the Formation of Hydrated Tissue Engineered Intervertebral Discs in Vivo

OBJECTIVES/GOALS: We evaluated the long-term success of tissue engineered intervertebral discs (TE-IVDs) cultured in flexible (FPLA) or stiff (PLA) support materials, hypothesizing that FPLA would maintain disc height and tissue hydration in the minipig spine. METHODS/STUDY POPULATION: TE-IVD: NP cells were encapsulated in alginate and NP plugs were placed in the center of FPLA cages. AF cells were encapsulated in type I collagen and pipetted around NP plugs. Implantation: Empty FPLA cages (n=4), and TE-IVDs cultured in FPLA (n=4) were implanted at C3-4 or C5-6 following complete discectomy (DX) in skeletally mature minipigs (n=4). Imaging and Quantification: Terminal disc height indices (DHI) were calculated from weekly x-rays using a previously described method, and results were compared to the PLA pilot study. T2 MRI scans were taken of levels treated with TE-IVDs to quantify disc hydration as previously described. RESULTS/ANTICIPATED RESULTS: FPLA cages restored DHIs to native levels until endpoint. In contrast, PLA cages fractured, and terminal DHIs were statistically similar to DX levels. Of the four levels treated with TE-IVDs, 2 were displaced from the disc space. Stabilized levels yielded DHIs which were statistically similar to native IVD and greater than displaced and DX levels. Displaced levels yielded DHIs which were significantly lower than native and stabilized levels, but greater than DX levels (P<0.05). T2 MRIs of stabilized TEIVDs revealed that levels treated with a construct maintained tissue hydration which was significantly greater than levels treated with an empty cage or DX levels (P<0.0001), but which was about half the hydration of native disc tissue. DISCUSSION/SIGNIFICANCE: Implanting TE-IVDs with FPLA support cages leads to disc height maintenance and the stabilization of hydrated tissues in the spine, enhancing the long term success of TE-IVD implants and providing a basis for clinical translation

Novel MIS 3D NAV single step pedicle screw system (SSPSS) : workflow, accuracy and initial clinical experience

Study Design: Prospective case series. Objective: SSPSS (single step pedicle screw system) was developed for minimally invasive spine surgery. We performed this study to report on safety, workflow, and our initial clinical experience with this novel technique. Methods: The prospective study was conducted on patients who underwent pedicle screw fixation between October 2017 and April 2018 using a novel single step 3D navigated pedicle screw system for MIS. Outcome measurements were obtained from intraoperative computerized tomography. The images were evaluated to determine pedicle wall penetration. We used a grading system to assess the severity of the pedicle wall penetration. Breaches were classified as grade 1 (<2 mm), grade 2 (2-4 mm), or grade 3 (<4 mm), (1) and as cranial, caudal, medial, and lateral. Results: Our study includes 135 screws in 24 patients. SSPSS eliminated K-wires and multiple steps traditionally necessary for MIS pedicle screw insertion. The median time per screw was 2.45 minutes. 3 screws were corrected intraoperatively. Pedicle wall penetration occurred in 14 screws (10%). Grade 1 breaches occurred in 4 screws (3%) and grade 2 breaches occurred in 10 screws (7%). Lateral breaches were observed more often than medial breaches. The accuracy rate in our study was 90% (Grade 0 breach). No revision surgeries were needed and no complications occurred. Conclusions: Our study suggests that SSPSS could be a safe, accurate, and efficient tool. Our accuracy rate is comparable to that found in the literature

Feasibility of smart glasses in supporting spinal surgical procedures in low- and middle-income countries: experiences from East Africa.

OBJECTIVE: Telemedicine technology has been developed to allow surgeons in countries with limited resources to access expert technical guidance during surgical procedures. The authors report their initial experience using state-of-the-art wearable smart glasses with wireless capability to transmit intraoperative video content during spine surgery from sub-Saharan Africa to experts in the US. METHODS: A novel smart glasses system with integrated camera and microphone was worn by a spine surgeon in Dar es Salaam, Tanzania, during 3 scoliosis correction surgeries. The images were transmitted wirelessly through a compatible software system to a computer viewed by a group of fellowship-trained spine surgeons in New York City. Visual clarity was determined using a modified Snellen chart, and a percentage score was determined on the smallest line that could be read from the 8-line chart on white and black backgrounds. A 1- to 5-point scale (from 1 = unrecognizable to 5 = optimal clarity) was used to score other visual metrics assessed using a color test card including hue, contrast, and brightness. The same scoring system was used by the group to reach a consensus on visual quality of 3 intraoperative points including instruments, radiographs (ability to see pedicle screws relative to bony anatomy), and intraoperative surgical field (ability to identify bony landmarks such as transverse processes, pedicle screw starting point, laminar edge). RESULTS: All surgeries accomplished the defined goals safely with no intraoperative complications. The average download and upload connection speeds achieved in Dar es Salaam were 45.21 and 58.89 Mbps, respectively. Visual clarity with the modified white and black Snellen chart was 70.8% and 62.5%, respectively. The average scores for hue, contrast, and brightness were 2.67, 3.33, and 2.67, respectively. Visualization quality of instruments, radiographs, and intraoperative surgical field were 3.67, 1, and 1, respectively. CONCLUSIONS: Application of smart glasses for telemedicine offers a promising tool for surgical education and remote training, especially in low- and middle-income countries. However, this study highlights some limitations of this technology, including optical resolution, intraoperative lighting, and internet connection challenges. With continued collaboration between clinicians and industry, future iterations of smart glasses technology will need to address these issues to stimulate robust clinical utilization

Essential Step-by-Step Techniques for Minimally Invasive Spinal Surgery

The ultimate resource for learning and mastering minimally invasive spine surgery techniques An estimated 1.5 million instrumented spinal procedures are performed every year in the US. The majority of decompressions and about 50% of fusion procedures can be performed completely or partially using minimally invasive spine surgery (MISS) techniques. The full potential of MISS techniques has yet to be realized. Essential Step-by-Step Techniques for Minimally Invasive Spinal Surgery by internationally renowned MISS neurosurgeon Roger Härtl, spine-neurosurgeon Rodrigo Navarro-Ramirez, and an impressive group of global multidisciplinary contributors is the most comprehensive and detailed textbook written to date on this topic. The foundation of the book is built on six interacting principles critical to surgical success, and MISS in particular: Target, Technology, Technique, Teaching and Training, Testing, and Talent. The text starts with an opening chapter on the definition of MISS and introduction of these principles. Fifty-six subsequent chapters provide a comprehensive discussion on how to utilize an MISS approach for a full spectrum of spinal pathologies using nuanced variations specific to the operating surgeon. To ensure readers are well versed in all aspects of MISS, these chapters include painstaking details on indications, contraindications, pathoanatomy, operating room set-up, step-by-step techniques, and postoperative management. Key Highlights Contributions from master spine surgeons across the world provide a balanced global perspective on mastering and incorporating diverse techniques into practice Invaluable clinical pearls including tips/tricks and complication avoidance High-quality images, figures, anatomic drawings, and imaging studies illustrate relevant anatomic approaches and corridors and delineate why anatomic masteryis critical to MISS Twenty-five videos enhance the ability to learn and implement MISS approaches This is a must-have resource for practicing spine surgeons interested in MISS who wish to learn the latest techniques from master surgeons and achieve optimal patient outcomes. The text and videos also provide a robust training tool for senior-level orthopaedic and neurosurgery residents and spine fellows