Accuracy of 2D Fluoroscopy with Preoperative CT Fused Neuronavigation in Thoracic and Lumbar Pedicle Screw Insertion

Aim: Pedicle screw fixation is an established technique in the lumbar and thoracic area. Fluoroscopy-guided screw placement and subsequently navigation have decreased the rate of misplaced screws, but no technique has wholly eliminated this risk. This paper aims to study the difference between the accuracy of the fluoroscopic guided screw placement to that of the 2D fluoroscopy- preop CT fused neuronavigation guided technique, a lesser-used navigation technique.  Material and Methods: This retrospective study reflects our results using both techniques between March 2018 and March 2019 in both degenerative or traumatic spinal pathology for thoracic and lumbar regions. The accuracy of the screw placement was measured using Mirza grading system on postoperative CT images. Results: A total number of 56 patients underwent spinal instrumentation surgery. A total of 274 screws were placed with a mean number of 4.89 screws per patient; 199 screws were implanted using neuronavigation and 75 using the freehand-2D fluoroscopy-guided technique.  The accuracy rate of pedicle screw placement in the freehand technique guided by 2D fluoroscopy was 88,00%. With the use of neuronavigation, the accuracy increased to 89,96%. Conclusion:  Pedicle screw placement accuracy is higher when guided by CT-fluoro matching neuronavigation compared to freehand fluoroscopy-guided technique and can be used in departments where there is no intraoperative O-arm or 3D fluoroscopy available

Prevalence of spine surgery navigation techniques and availability in Africa: A cross-sectional study

Background: Africa has a large burden of spine pathology but has limited and insufficient infrastructure to manage these spine disorders. Therefore, we conducted this e-survey to assess the prevalence and identify the determinants of the availability of spine surgery navigation techniques in Africa. Materials and methods: A two-part questionnaire was disseminated amongst African neurological and orthopedic surgery consultants and trainees from January 24 to February 23, 2021. The Chi-Square, Fisher Exact, and Kruskal-Wallis tests were used to evaluate bivariable relationships, and a p-value \u3c0.05 was considered statistically significant. Results: We had 113 respondents from all regions of Africa. Most (86.7 %) participants who practiced or trained in public centers and centers had an annual median spine case surgery volume of 200 (IQR = 190) interventions. Fluoroscopy was the most prevalent spine surgery navigation technique (96.5 %), followed by freehand (55.8 %), stereotactic without intraoperative CT scan (31.9 %), robotic with intraoperative CT scan (29.2 %), stereotactic with intraoperative CT scan (8.8 %), and robotic without intraoperative CT scan (6.2 %). Cost of equipment (94.7 %), lack of trained staff to service (63.7 %), or run the equipment (60.2 %) were the most common barriers to the availability of spine instrumentation navigation. In addition, there were significant regional differences in access to trained staff to run and service the equipment (P = 0.001). Conclusion: There is a need to increase access to more advanced navigation techniques, and we identified the determinants of availability

Augmented navigation

Spinal fixation procedures have the inherent risk of causing damage to vulnerable anatomical structures such as the spinal cord, nerve roots, and blood vessels. To prevent complications, several technological aids have been introduced. Surgical navigation is the most widely used, and guides the surgeon by providing the position of the surgical instruments and implants in relation to the patient anatomy based on radiographic images. Navigation can be extended by the addition of a robotic arm to replace the surgeon’s hand to increase accuracy. Another line of surgical aids is tissue sensing equipment, that recognizes different tissue types and provides a warning system built into surgical instruments. All these technologies are under continuous development and the optimal solution is yet to be found. The aim of this thesis was to study the use of Augmented Reality (AR), Virtual Reality (VR), Artificial Intelligence (AI), and tissue sensing technology in spinal navigation to improve precision and prevent surgical errors. The aim of Paper I was to develop and validate an algorithm for automatizing the intraoperative planning of pedicle screws. An AI algorithm for automatic segmentation of the spine, and screw path suggestion was developed and evaluated. In a clinical study of advanced deformity cases, the algorithm could provide correct suggestions for 86% of all pedicles—or 95%, when cases with extremely altered anatomy were excluded. Paper II evaluated the accuracy of pedicle screw placement using a novel augmented reality surgical navigation (ARSN) system, harboring the above-developed algorithm. Twenty consecutively enrolled patients, eligible for deformity correction surgery in the thoracolumbar region, were operated on using the ARSN system. In this cohort, we found a pedicle screw placement accuracy of 94%, as measured according to the Gertzbein grading scale. The primary goal of Paper III was to validate an extension of the ARSN system for placing pedicle screws using instrument tracking and VR. In a porcine cadaver model, it was demonstrated that VR instrument tracking could successfully be integrated with the ARSN system, resulting in pedicle devices placed within 1.7 ± 1.0 mm of the planed path. Paper IV examined the feasibility of a robot-guided system for semi-automated, minimally invasive, pedicle screw placement in a cadaveric model. Using the robotic arm, pedicle devices were placed within 0.94 ± 0.59 mm of the planned path. The use of a semi-automated surgical robot was feasible, providing a higher technical accuracy compared to non-robotic solutions. Paper V investigated the use of a tissue sensing technology, diffuse reflectance spectroscopy (DRS), for detecting the cortical bone boundary in vertebrae during pedicle screw insertions. The technology could accurately differentiate between cancellous and cortical bone and warn the surgeon before a cortical breach. Using machine learning models, the technology demonstrated a sensitivity of 98% [range: 94-100%] and a specificity of 98% [range: 91-100%]. In conclusion, several technological aids can be used to improve accuracy during spinal fixation procedures. In this thesis, the advantages of adding AR, VR, AI and tissue sensing technology to conventional navigation solutions were studied

Prevalence of spine surgery navigation techniques and availability in Africa: A cross-sectional study

Background: Africa has a large burden of spine pathology but has limited and insufficient infrastructure to manage these spine disorders. Therefore, we conducted this e-survey to assess the prevalence and identify the determinants of the availability of spine surgery navigation techniques in Africa. Materials and methods: A two-part questionnaire was disseminated amongst African neurological and orthopedic surgery consultants and trainees from January 24 to February 23, 2021. The Chi-Square, Fisher Exact, and Kruskal-Wallis tests were used to evaluate bivariable relationships, and a p-value \u3c0.05 was considered statistically significant. Results: We had 113 respondents from all regions of Africa. Most (86.7 %) participants who practiced or trained in public centers and centers had an annual median spine case surgery volume of 200 (IQR = 190) interventions. Fluoroscopy was the most prevalent spine surgery navigation technique (96.5 %), followed by freehand (55.8 %), stereotactic without intraoperative CT scan (31.9 %), robotic with intraoperative CT scan (29.2 %), stereotactic with intraoperative CT scan (8.8 %), and robotic without intraoperative CT scan (6.2 %). Cost of equipment (94.7 %), lack of trained staff to service (63.7 %), or run the equipment (60.2 %) were the most common barriers to the availability of spine instrumentation navigation. In addition, there were significant regional differences in access to trained staff to run and service the equipment (P = 0.001). Conclusion: There is a need to increase access to more advanced navigation techniques, and we identified the determinants of availability

Exploiting Temporal Image Information in Minimally Invasive Surgery

Minimally invasive procedures rely on medical imaging instead of the surgeons direct vision. While preoperative images can be used for surgical planning and navigation, once the surgeon arrives at the target site real-time intraoperative imaging is needed. However, acquiring and interpreting these images can be challenging and much of the rich temporal information present in these images is not visible. The goal of this thesis is to improve image guidance for minimally invasive surgery in two main areas. First, by showing how high-quality ultrasound video can be obtained by integrating an ultrasound transducer directly into delivery devices for beating heart valve surgery. Secondly, by extracting hidden temporal information through video processing methods to help the surgeon localize important anatomical structures. Prototypes of delivery tools, with integrated ultrasound imaging, were developed for both transcatheter aortic valve implantation and mitral valve repair. These tools provided an on-site view that shows the tool-tissue interactions during valve repair. Additionally, augmented reality environments were used to add more anatomical context that aids in navigation and in interpreting the on-site video. Other procedures can be improved by extracting hidden temporal information from the intraoperative video. In ultrasound guided epidural injections, dural pulsation provides a cue in finding a clear trajectory to the epidural space. By processing the video using extended Kalman filtering, subtle pulsations were automatically detected and visualized in real-time. A statistical framework for analyzing periodicity was developed based on dynamic linear modelling. In addition to detecting dural pulsation in lumbar spine ultrasound, this approach was used to image tissue perfusion in natural video and generate ventilation maps from free-breathing magnetic resonance imaging. A second statistical method, based on spectral analysis of pixel intensity values, allowed blood flow to be detected directly from high-frequency B-mode ultrasound video. Finally, pulsatile cues in endoscopic video were enhanced through Eulerian video magnification to help localize critical vasculature. This approach shows particular promise in identifying the basilar artery in endoscopic third ventriculostomy and the prostatic artery in nerve-sparing prostatectomy. A real-time implementation was developed which processed full-resolution stereoscopic video on the da Vinci Surgical System

Proof of Concept: Wearable Augmented Reality Video See-Through Display for Neuro-Endoscopy

In mini-invasive surgery and in endoscopic procedures, the surgeon operates without a direct visualization of the patient’s anatomy. In image-guided surgery, solutions based on wearable augmented reality (AR) represent the most promising ones. The authors describe the characteristics that an ideal Head Mounted Display (HMD) must have to guarantee safety and accuracy in AR-guided neurosurgical interventions and design the ideal virtual content for guiding crucial task in neuro endoscopic surgery. The selected sequence of AR content to obtain an effective guidance during surgery is tested in a Microsoft Hololens based app

Augmented Reality: Mapping Methods and Tools for Enhancing the Human Role in Healthcare HMI

Background: Augmented Reality (AR) represents an innovative technology to improve data visualization and strengthen the human perception. Among Human–Machine Interaction (HMI), medicine can benefit most from the adoption of these digital technologies. In this perspective, the literature on orthopedic surgery techniques based on AR was evaluated, focusing on identifying the limitations and challenges of AR-based healthcare applications, to support the research and the development of further studies. Methods: Studies published from January 2018 to December 2021 were analyzed after a comprehensive search on PubMed, Google Scholar, Scopus, IEEE Xplore, Science Direct, and Wiley Online Library databases. In order to improve the review reporting, the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used. Results: Authors selected sixty-two articles meeting the inclusion criteria, which were categorized according to the purpose of the study (intraoperative, training, rehabilitation) and according to the surgical procedure used. Conclusions: AR has the potential to improve orthopedic training and practice by providing an increasingly human-centered clinical approach. Further research can be addressed by this review to cover problems related to hardware limitations, lack of accurate registration and tracking systems, and absence of security protocols

Transtubular Resection of Spinal Intradural Lésions : Techniques, Results, & Complications.

Le travail de thèse ici présenté a été publié sous forme d’un article scientifique ayant le titre « Image guided tailored access resection (IMTAR) of spinal intradural tumors. Technical report of 13 cases » L’article présente les résultats de la chirurgie per « accès minime » (MAS) utilisée dans notre établissement hospitalier avec une implémentation de la technique guidée par image que nous appelons « technique de navigation chirurgicale guidée par fusion d’image » (en anglais : Image Merge Tailored Access Resection ou IMTAR). IMTAR représente l’application d’une technique de fusion d’image déjà existante pour la chirurgie crânienne qui consiste à fusionner les images de la résonance magnétique préopératoire avec les images de fluoroscopie 3D obtenues pendant la chirurgie pour naviguer à la fois les structures osseuses et les tissus mous. La fusion d’image donne au chirurgien la possibilité de mieux planifier l’accès chirurgical par la navigation virtuelle sur les images avant l’incision. Le chirurgien peut donc adapter l’abord chirurgical selon la localisation de la lésion et également adapter la résection d’os en fonction de la fenêtre d’exposition nécessaire pour la visualisation de la lésion tumorale. Le choix d’utiliser la technique IMTAR est pris en préopératoire par le chirurgien en fonction de la disponibilité de cette technique dans un contexte de chirurgie élective. La technique est une implémentation d’une technique déjà existante et bien validée par la littérature courante dont l’utilisation est faite au niveau crânien, mais ici adaptée à la chirurgie spinale. L’utilisation de la technique IMTAR a pour but de réduire le risque d’erreur de niveau de la localisation des lésions tumorales spinales, situation décrite en littérature. De plus, le choix de trajectoire d’accès trans-musculaire selon la localisation de la lésion tumorale pourrait améliorer l’angle d’accès aux lésions et minimiser le volume d’os enlevé pendant l’abord chirurgical. Sur la série préliminaire de 13 patients dont les résultats sont contenus dans l’article ici joint, la technique IMTAR a montré des résultats d’exérèse tumorale superposables aux résultats de la technique MAS non-naviguée. La procédure IMTAR semble être moins invasive en termes de résection osseuse et elle permet une meilleure localisation de la lésion. Le présent travail de thèse s’est déroulé dans le contexte de l’étude IMTAR, catégorie A (Protocole n. 172/15) approuvé par le CER VD et en cours depuis 01.01.2017 au CHUV de Lausanne (investigateurs principales: Dr Rodolfo Maduri, Dr John Michael Duff). Les perspectives futures pour cette étude sont de décrire les résultats chirurgicaux sur une « prospective cohort » de patients ayant bénéficié de la technique IMTAR et de la technique MAS non-naviguée jusqu’à la date de fin de l’étude. L’étude IMTAR a pour but d’évaluer les résultats de l’utilisation de la technique IMTAR pour les tumeurs spinales par rapport à la technique de chirurgie MAS classique en termes de minimisation de la morbidité associée à l’abord chirurgical, de la réduction du risque d’une instabilité spinale iatrogène et de l’optimisation de l’efficacité de la résection de la tumeur. -- - OBJECTIVE: Standard translaminar approaches for intradural extramedullary (IDEM) tumors require extensive soft tissue dissection and partial facet removal. Ventral lesions may necessitate wider bone resection with sub- sequent possible spinal instability. Any manipulation of an already compromised spinal cord may lead to neurological injury. We describe an image-guided minimal access technique for IDEM tumor resection. - METHODS: Retrospective chart review of 13 consecutive patients after institutional ethics committee approval. We superimpose preoperative magnetic resonance imaging data with intraoperative 3-dimensional fluoroscopic im- ages, allowing to simultaneously visualize osseous anat- omy and the soft tissue lesion using appropriate windowing. We then plan optimal angle of trajectory to the tumor, which defines the skin incision and the trans- muscular trajectory. A tubular retractor is placed to span the tumor. Microsurgical tumor resection is then carried out using this angle of approach. - RESULTS: Thirteen patients (mean age. 57 years; male-to- female ratio, 10:3) were operated on during 28 months. Gross total resection was achieved in all patients. Neuro- logical improvement occurred in 12 of the 13 patients. There was no neurological deficit outside of the expected sensory loss due to intentional nerve root sacrifice. No mechanical pain nor tumor recurrence were noted during the follow-up (mean, 16 months; range, 2e30 months). - CONCLUSIONS: Image merge tailored access resection appears to be at least equivalent in terms of tumor resec- tion, blood loss, and complications to other tubular tech- niques. It may reduce risks of neurological deficit and spine instability. Image merge tailored access resection is a novel application of merging intraoperative fluoroscopic images with preoperative magnetic resonance images for tailored IDEM resection

Augmented reality (AR) for surgical robotic and autonomous systems: State of the art, challenges, and solutions

Despite the substantial progress achieved in the development and integration of augmented reality (AR) in surgical robotic and autonomous systems (RAS), the center of focus in most devices remains on improving end-effector dexterity and precision, as well as improved access to minimally invasive surgeries. This paper aims to provide a systematic review of different types of state-of-the-art surgical robotic platforms while identifying areas for technological improvement. We associate specific control features, such as haptic feedback, sensory stimuli, and human-robot collaboration, with AR technology to perform complex surgical interventions for increased user perception of the augmented world. Current researchers in the field have, for long, faced innumerable issues with low accuracy in tool placement around complex trajectories, pose estimation, and difficulty in depth perception during two-dimensional medical imaging. A number of robots described in this review, such as Novarad and SpineAssist, are analyzed in terms of their hardware features, computer vision systems (such as deep learning algorithms), and the clinical relevance of the literature. We attempt to outline the shortcomings in current optimization algorithms for surgical robots (such as YOLO and LTSM) whilst providing mitigating solutions to internal tool-to-organ collision detection and image reconstruction. The accuracy of results in robot end-effector collisions and reduced occlusion remain promising within the scope of our research, validating the propositions made for the surgical clearance of ever-expanding AR technology in the future

Is 2D Fluoroscopy Reliable in Minimal Invasive Spine Surgery? Evaluation of Perforation Indices in MIS-TLIF

Objective The aim of this study is to assess reliability of 2D Fluoroscopy in Minimal Invasive Surgery Transforaminal Lumbar Interbody Fusion (MIS-TLIF) through evaluation of perforation indices in 1,200 percutaneous pedicle screw instrumentation. Methods It is a single center retrospective study of 300 consecutive patients undergoing single level minimal invasive lumbar interbody fusion surgery (MIS-TLIF) under 2D Fluoroscopy. Percutaneous pedicle screws were analyzed with post-operative CT scan to assess accuracy of pedicle screw placement, Grades of perforation, Critical vs. Non critical Nature, Location of violation. Neurological implications of misplaced screws, Demographic, Clinical Parameters, outcome scores viz. Visual Analogue Score (VAS), Oswestry Disability Index (ODI) were also assessed. Results Overall rate of screw perforation was 5% (60/1,200) with different grades of perforation(Medial=24, Lateral=30, Inferior=1, Superior=5, Anterior=0) (Grade 1=42, Grade 2=18, Grade 3=0). Critical perforations were noted in 18 patient but none of the patients with critical and non critical perforation developed any neurological complications or post-operative leg pain. Conclusion This study showed overall pedicle perforation rate of 5% (60/1,200) in lower lumbar single level MIS-TLIF for grade 1 degenerative spondylolisthesis including grade 1 perforations are 3.5% and grade 2 perforation are 1.5%. 2D Fluoroscopy guided percutaneous pedicle screws placement with appropriate technique in MIS-TLIF is an acceptable and reliable procedure with low rates of screw related complications and revisions