Integrated navigation and visualisation for skull base surgery

Skull base surgery involves the management of tumours located on the underside of the brain and the base of the skull. Skull base tumours are intricately associated with several critical neurovascular structures making surgery challenging and high risk. Vestibular schwannoma (VS) is a benign nerve sheath tumour arising from one of the vestibular nerves and is the commonest pathology encountered in skull base surgery. The goal of modern VS surgery is maximal tumour removal whilst preserving neurological function and maintaining quality of life but despite advanced neurosurgical techniques, facial nerve paralysis remains a potentially devastating complication of this surgery. This thesis describes the development and integration of various advanced navigation and visualisation techniques to increase the precision and accuracy of skull base surgery. A novel Diffusion Magnetic Resonance Imaging (dMRI) acquisition and processing protocol for imaging the facial nerve in patients with VS was developed to improve delineation of facial nerve preoperatively. An automated Artificial Intelligence (AI)-based framework was developed to segment VS from MRI scans. A user-friendly navigation system capable of integrating dMRI and tractography of the facial nerve, 3D tumour segmentation and intraoperative 3D ultrasound was developed and validated using an anatomically-realistic acoustic phantom model of a head including the skull, brain and VS. The optical properties of five types of human brain tumour (meningioma, pituitary adenoma, schwannoma, low- and high-grade glioma) and nine different types of healthy brain tissue were examined across a wavelength spectrum of 400 nm to 800 nm in order to inform the development of an Intraoperative Hypserpectral Imaging (iHSI) system. Finally, functional and technical requirements of an iHSI were established and a prototype system was developed and tested in a first-in-patient study

Surgical approaches for possible positions of an olfactory implant to stimulate the olfactory bulb

Introduction: Current scientific developments seem to allow for an "olfactory implant"in analogy to cochlear implants. However, the position and surgical approaches for electrical stimulation of the olfactory system are unclear. Methods: In a human anatomic cadaver study, we investigated different endoscopic approaches to electrically stimulate the olfactory bulb (OB) based on the following considerations: (1) the stimulating electrode should be close to the OB. (2) The surgical procedure should be as non-invasive and safe as possible and (3) as easy as possible for an experienced ENT surgeon. Results: In summary, the endoscopic intracranial positioning of the electrode via a widened ostium of the fila olfactoria or a frontal sinus surgery like a Draf IIb procedure is a good option in terms of patients' risk, degree of difficulty for ENT surgeons, and position to the OB. Endoscopic intranasal positioning appeared to be the best option in terms of patient risk and the degree of difficulty for ENT surgeons. Although a bigger approach to the OB using a drill and the combined intranasal endoscopic and external approach enabled a close placement of the electrode to the OB, they do not seem relevant in practice due to their higher invasiveness. Conclusion: The study suggested that an intranasal positioning of a stimulating electrode is possible, with placements beneath the cribriform plate, extra- or intracranially, applying elegant surgical techniques with low or medium risk to the patient and a close placement to OB

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

The HoloLens in Medicine: A systematic Review and Taxonomy

The HoloLens (Microsoft Corp., Redmond, WA), a head-worn, optically see-through augmented reality display, is the main player in the recent boost in medical augmented reality research. In medical settings, the HoloLens enables the physician to obtain immediate insight into patient information, directly overlaid with their view of the clinical scenario, the medical student to gain a better understanding of complex anatomies or procedures, and even the patient to execute therapeutic tasks with improved, immersive guidance. In this systematic review, we provide a comprehensive overview of the usage of the first-generation HoloLens within the medical domain, from its release in March 2016, until the year of 2021, were attention is shifting towards it's successor, the HoloLens 2. We identified 171 relevant publications through a systematic search of the PubMed and Scopus databases. We analyze these publications in regard to their intended use case, technical methodology for registration and tracking, data sources, visualization as well as validation and evaluation. We find that, although the feasibility of using the HoloLens in various medical scenarios has been shown, increased efforts in the areas of precision, reliability, usability, workflow and perception are necessary to establish AR in clinical practice.Comment: 35 pages, 11 figure

Herausforderungen bei der Prozessunterstützung im Operationssaal: Aktivitätserfassung und Datenspeicherung als Grundlage zur Erkennung des chirurgischen Prozesses

Die aktuelle Gesundheitsversorgung ist geprägt durch eine steigende Komplexität, die durch die Verzahnung verschiedener medizinischer Bereiche und die Nutzung immer komplexerer, technisch unterstützter Behandlungsmöglichkeiten bedingt ist. Gleichzeitig stehen Kliniken und das medizinische Fachpersonal unter einem hohen Kosten- und Zeitdruck. Für das Erreichen einer optimalen Behandlung des Patienten durch minimalinvasive und mikrochirurgische Eingriffe sind zunehmend Ansätze notwendig, die auf eine Interoperabilität verschiedener Systeme setzen und die Verwendung von zusätzlichen (semi )automatischen Unterstützungssystemen ermöglichen. Diese Arbeit beschäftigt sich mit Herausforderungen bei der Prozessunterstützung im Operationssaal. Dabei liegt der Fokus auf der Aktivitätserfassung und Datenspeicherung als Grundlage zur Erkennung des chirurgischen Prozesses. In einem ersten Schritt wurde ein theoretisches Vorgehensmodell für die intraoperative Prozessunterstützung auf der Basis eines geschlossenen Regelkreises entwickelt. Dabei steht der chirurgische Prozess im Zentrum. In weiteren Schritten wurden ein System zur Erfassung des aktuellen Arbeitsschrittes auf Basis der vorhandenen Videodaten (z.B. Mikroskopie, Ultraschall) sowie eine zentrale Speicherlösung für den Operationssaal entwickelt. Diese zentralen Komponenten sollen es Systemen ermöglichen, während des Eingriffs Daten an die verschiedenen Nutzer bereitzustellen und diese gleichzeitig für eine spätere Dokumentation vorzuhalten. Im weiteren Verlauf der Arbeit werden Ansätze zum Erreichen einer Interoperabilität von Medizingeräten und IT-Systemen im Gesundheitswesen vorgestellt, da technische Systeme neben zusätzlicher Sensorik eine wertvolle Informationsquelle für die Erfassung des aktuellen Prozesses im Operationssaal darstellen. Im Rahmen der Arbeiten des Projektes OR.NET (BMBF, 2012-2016) wurde mit der IEEE 11073-SDC-Standardfamilie eine Möglichkeit zur offenen Vernetzung geschaffen. Konzeptionell integriert werden die Systeme durch eine Beschreibung von Mehrwertdiensten von der einfachen Anzeige von Geräteparametern bis hin zur Teilautomatisierung von technischen Arbeitsschritten auf Basis des Kommunikationsstandards IEEE11073-SDC. Diese wurden basierend auf dieser Basistechnologie gemeinsam mit verschiedenen Projektpartnern entwickelt und mit Klinikern und Klinikbetreibern evaluiert. Die Ergebnisse der Evaluation zeigen, dass durch eine syntaktische und semantische Interoperabilität neue, nutzbringende Funktionen umgesetzt und die Arbeit der verschiedenen Nutzergruppen im Gesundheitssystem effektiv unterstützt werden können.:Inhalt Abstract Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis 1 Einleitung 1.1 Motivation für diese Arbeit 1.2 Zielsetzung der Arbeit 2 Grundlagen der Arbeit 2.1 Aktuelle Operationssäle 2.2 Prozessunterstützung 2.2.1 Workflow und Prozessmodellierung 2.2.2 Workflow in der Medizin 2.2.3 Kontextsensitive Systeme 2.3 Klinische Anwendungsfälle im Rahmen der Arbeit 2.3.1 Intrakranielle Eingriffe am Gehirn 2.3.2 Transsphenoidale Hypophysenadenomentfernung 2.3.3 Sanierende Ohr-OP 3 Vorgehensmodell zur Prozessunterstützung 3.1 Interpretation und Action 3.2 Data analysis und Monitoring 3.3 Mögliche Herangehensweisen bei der Umsetzung einer Prozessunterstützung 4 Erfassung prozessrelevanter Daten im Operationssaal 4.1 Stand der Forschung 4.1.1 Team Assessment und Performanzüberwachung 4.1.2 OP-Dokumentation, Qualitätssicherung und Elektronische Patientenakte (EPA) 4.1.3 Workflow Recognition 4.2 Erkennung der Interaktion zwischen Medizingerät und medizinischem Personal basierend auf der Analyse von Videodaten 4.2.1 Methode 4.2.2 Evaluation 4.2.3 Diskussion 4.3 Erfassung von Informationen durch OP-Integration 4.3.1 Stand der Forschung 4.3.2 Grundlagen des Projektes OR.NET 4.3.3 Zusammenfassung 5 Datenspeicherung im Operationssaal (Surgical Data Recorder und die Erweiterungen auf Basis von OR.NET) 5.1 Surgical Data Recorder 5.1.1 Anforderungsanalyse 5.1.2 Systemkonzept 5.1.3 Evaluationsstudie 5.2 Anpassungen des Datenaufzeichnungskonzeptes im Rahmen des OR.NET-Projekts 5.3 Diskussion und Vergleich der Ansätze 6 Mehrwertdienste auf Basis einer offenen Vernetzung 6.1 Setzen von eingriffsspezifischen Informationen auf den angeschlossenen Geräten 6.2 Anzeige von Informationen im Sichtfeld des Chirurgen 6.3 Mehrwerte durch Datenintegration 6.4 Funktionen mit Nutzung von Prozessinformationen 7 Entwicklung der OP-Demonstratoren und Evaluation der implementierten Mehrwertdienste mit verschiedenen Anwendergruppen 7.1 Anforderungsanalyse für den Leipziger Demonstrator 7.2 Infrastruktur des Demonstrators 7.3 Integrationsszenarien in den Demonstratoren 7.4 Umgesetzte Mehrwertdienste im Leipziger Demonstrator 7.5 Vorgehen bei der Evaluation des Leipziger Demonstrators 7.5.1 Technische Evaluation 7.5.2 Klinische Evaluation 7.6 Ergebnisse der Evaluation 7.6.1 Technische Evaluation 7.6.2 Klinische Evaluation 7.7 Diskussion der Ergebnisse 8 Ausblick auf Weiterentwicklungen der offenen Vernetzung im Operationssaal 9 Zusammenfassung 10 Literatur 11 Anhang 11.1 Modellierung der sanierenden Ohr-OP als EPK inkl. möglicher Vernetzungsszenarien 11.2 Übersicht der umgesetzten Use-Cases im Leipziger Demonstrator 136 11.3 Fragenkatalog OP-Personal 11.4 Fragebogen Betreiber 12 Eigenständigkeitserklärung 13 Eigene Literatur 14 Danksagun

25th International Congress of the European Association for Endoscopic Surgery (EAES) Frankfurt, Germany, 14-17 June 2017 : Oral Presentations

Introduction: Ouyang has recently proposed hiatal surface area (HSA) calculation by multiplanar multislice computer tomography (MDCT) scan as a useful tool for planning treatment of hiatus defects with hiatal hernia (HH), with or without gastroesophageal reflux (MRGE). Preoperative upper endoscopy or barium swallow cannot predict the HSA and pillars conditions. Aim to asses the efficacy of MDCT’s calculation of HSA for planning the best approach for the hiatal defects treatment. Methods: We retrospectively analyzed 25 patients, candidates to laparoscopic antireflux surgery as primary surgery or hiatus repair concomitant with or after bariatric surgery. Patients were analyzed preoperatively and after one-year follow-up by MDCT scan measurement of esophageal hiatus surface. Five normal patients were enrolled as control group. The HSA’s intraoperative calculation was performed after complete dissection of the area considered a triangle. Postoperative CT-scan was done after 12 months or any time reflux symptoms appeared. Results: (1) Mean HSA in control patients with no HH, no MRGE was cm2 and similar in non-complicated patients with previous LSG and cruroplasty. (2) Mean HSA in patients candidates to cruroplasty was 7.40 cm2. (3) Mean HSA in patients candidates to redo cruroplasty for recurrence was 10.11 cm2. Discussion. MDCT scan offer the possibility to obtain an objective measurement of the HSA and the correlation with endoscopic findings and symptoms. The preoperative information allow to discuss with patients the proper technique when a HSA[5 cm2 is detected. During the follow-up a correlation between symptoms and failure of cruroplasty can be assessed. Conclusions: MDCT scan seems to be an effective non-invasive method to plan hiatal defect treatment and to check during the follow-up the potential recurrence. Future research should correlate in larger series imaging data with intraoperative findings

Combined brain language connectivity and intraoperative neurophysiologic techniques in awake craniotomy for eloquent-area brain tumor resection

Speech processing can be disturbed by primary brain tumors (PBT). Improvement of presurgical planning techniques decrease neurological morbidity associated to tumor resection during awake craniotomy. The aims of this work were: 1. To perform Diffusion Kurtosis Imaging based tractography (DKI-tract) in the detection of brain tracts involved in language; 2. To investigate which factors contribute to functional magnetic resonance imaging (fMRI) maps in predicting eloquent language regional reorganization; 3. To determine the technical aspects of accelerometric (ACC) recording of speech during surgery. DKI-tracts were streamlined using a 1.5T magnetic resonance scanner. Number of tracts and fiber pathways were compared between DKI and standard Diffusion Tensor Imaging (DTI) in healthy subjects (HS) and PBT patients. fMRI data were acquired using task-specific and resting-state paradigms during language and motor tasks. After testing intraoperative fMRI’s influence on direct cortical stimulation (DCS) number of stimuli, graph-theory measures were extracted and analyzed. Regarding speech recording, ACC signals were recorded after evaluating neck positions and filter bandwidths. To test this method, language disturbances were recorded in patients with dysphonia and after applying DCS in the inferior frontal gyrus. In contrast, HS reaction time was recorded during speech execution. DKI-tract showed increased number of arcuate fascicle tracts in PBT patients. Lower spurious tracts were identified with DKI-tract. Intraoperative fMRI and DCS showed similar stimuli in comparison with DCS alone. Increased local centrality accompanied language ipsilateral and contralateral reorganization. ACC recordings showed minor artifact contamination when placed at the suprasternal notch using a 20-200 Hz filter bandwidth. Patients with dysphonia showed decreased amplitude and frequency in comparison with HS. ACC detected an additional 11% disturbances after DCS, and a shortening of latency within the presence of a loud stimuli during speech execution. This work improved current knowledge on presurgical planning techniques based on brain structural and functional neuroimaging connectivity, and speech recordingA função linguística do ser humano pode ser afetada pela presença de tumores cerebrais (TC) A melhoria de técnicas de planeamento pré-cirurgico diminui a morbilidade neurológica iatrogénica associada ao seu tratamento cirúrgico. O objetivo deste trabalho é: 1. Testar a fiabilidade da tractografia estimada por difusor de kurtose (tract-DKI), dos feixes cerebrais envolvidos na linguagem 2. Identificar os fatores que contribuem para o mapeamento linguagem por ressonância magnética funcional (RMf) na predição da neuroplasticidade. 3. Identificar aspetos técnicos do registo da linguagem por accelerometria (ACC). A DKI-tract foi estimada após realização de RM cerebral com 1.5T. O número e percurso das fibras foi avaliado. A RMf foi adquirida durante realização de tarefas linguísticas, motoras, e em repouso. Foi testada influência dos mapas de ativação calculados por RMf, no número de estímulos realizados durante a estimulação direta cortical (EDC) intraoperatória. Medidas de conectividade foram extraídas de regiões cerebrais. A posição e filtragem de sinal ACC foram estudadas após vocalização de palavras. O sinal ACC obtido em voluntários foi comparado com doentes disfónicos, após estimulação do giro inferior frontal, e após a adição de um estímulo sonoro perturbador durante vocalização. A tract-DKI estimou um elevado número de fascículos do feixe arcuato com menos falsos negativos. Os mapas linguísticos de RMf intraoperatória, não influenciou a EDC. Medidas de centralidade aumentaram após neuroplasticidade ipsilateral e contralateral. A posição supraesternal e a filtragem de sinal ACC entre 20-200Hz demonstrou menor ruido de contaminação. Este método identificou diminuição de frequência e amplitude em doentes com disfonia, 11% de erros linguísticos adicionais após estimulação e diminuição do tempo de latência quando presente o sinal sonoro perturbador. Este trabalho promoveu a utilização de novas técnicas no planeamento pré-cirúrgico do doente com tumor cerebral e alterações da linguagem através do estudo de conectividade estrutural, funcional e registo da linguagem

Spine Surgery

We are very excited to introduce this new book on spinal surgery, which follows the curriculum of the EUROSPINE basic and advanced diploma courses. The approach we take is a purely case-based one, in which each case illustrates the concepts surrounding the treatment of a given pathology, including the uncertainties and problems in decision-making. The readers will notice that in many instances a lack of evidence for a given treatment exists. So decisions taken are usually not a clearcut matter of black or white, but merely different shades of gray. Probably in a lot of cases, there is often more than one option to treat the patient. The authors were asked to convey this message to the reader, giving him a guidance as what would be accepted within the mainstream. In addition, the reader is provided with the most updated literature and evidence on the topic. Most of the authors are teachers in the courses of EUROSPINE or other national societies with often vast clinical experience and have given their own perspective and reasoning. We believe that the readers will profit very much from this variety and bandwidth of knowledge provided for them in the individual chapters. We have given the authors extensive liberty as to what they consider the best solution for their case. It is thus a representative picture of what is considered standard of care for spine pathologies in Europe. We hope that this book will be an ideal complement for trainees to the courses they take. Munich, Germany Bernhard Meyer Offenbach, Germany Michael Rauschman

Next generation of growth-sparing techniques: preliminary clinical results of a magnetically controlled growing rod in 14 patients

Session 3A - Early Onset Scoliosis: Paper no. 33SUMMARY: Growth-sparing techniques are commonly used for the treatment of progressive EOS. The standard growing rod (GR) technique requires multiple surgeries for lengthening. The preliminary results of MCGR has shown the comparable outcomes to standard GR without the need for repeated surgery which can be expected to reduce the overall complication rate in GR surgery. INTRODUCTION: The growing rod (GR) technique for management of progressive Early-Onset Scoliosis (EOS) is a viable alternative but with a high complication rate attributed to frequent surgical lengthenings. The safety and efficacy of a non-invasive Magnetically Controlled Growing Rod (MCGR) has been previously reported in a porcine model. We are reporting the preliminary results of this technique in EOS. METHODS: Retrospective review of prospectively collected multi-center data. Only patients who underwent MCGR surgery and at least 3 subsequent spinal distractions were included in this preliminary review. Distractions were performed in clinic without anesthesia or analgesics. T1-T12 and T1-S1 height and the distraction distance inside the actuator were analyzed in addition to conventional clinical and radiographic data. RESULTS: Patients (N=14; 7 F and 7 M) had a mean age of 8y+10m (3y+6m to 12y+7m) and underwent a total of 14 index surgeries (SR: index single rod in 5 and DR: dual rod in 9) and 91 distractions. There were 5 idiopathic, 4 neuromuscular, 2 congenital, 2 syndromic and one NF. Mean follow-up (FU) was 10 months (5.8-18.2). Mean Cobb changed from 57° pre-op to 35° post-op and correction was maintained (35°) at latest FU. T1-T12 increased by 4 mm for SR and 10 mm for DR with mean monthly gain of 0.5 and 1.39, respectively. T1-S1 gain was 4 mm for SR and 17 mm for DR with mean monthly gain of 0.5 mm for SR and 2.35 mm for DR. The mean interval between index surgery and the first distraction was 66 days and thereafter was 43 days. Complications included one superficial infection in (SR), one prominent implant (DR) and minimal loss of initial distraction in three after index MCGR (all SR). Overall, partial loss of distraction was observed following 14 of the 91 distractions (one DR and 13 SR). This loss was regained in subsequent distractions. There was no neurologic deficit or implant failure. CONCLUSION: MCGR appears to be safe and provided adequate distraction similar to the standard GR technique without the need for repeated surgeries. DR patients had better initial curve correction and greater spinal height. No major complications were observed during the short follow-up period. The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an ‘off label’ use).postprin