AUTOMATIC LOCALIZATION OF EPIDURAL NEEDLE ENTRY SITE WITH LUMBAR ULTRASOUND IMAGE PROCESSING

Ph.DDOCTOR OF PHILOSOPH

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

Augmented Reality Ultrasound Guidance in Anesthesiology

Real-time ultrasound has become a mainstay in many image-guided interventions and increasingly popular in several percutaneous procedures in anesthesiology. One of the main constraints of ultrasound-guided needle interventions is identifying and distinguishing the needle tip from needle shaft in the image. Augmented reality (AR) environments have been employed to address challenges surrounding surgical tool visualization, navigation, and positioning in many image-guided interventions. The motivation behind this work was to explore the feasibility and utility of such visualization techniques in anesthesiology to address some of the specific limitations of ultrasound-guided needle interventions. This thesis brings together the goals, guidelines, and best development practices of functional AR ultrasound image guidance (AR-UIG) systems, examines the general structure of such systems suitable for applications in anesthesiology, and provides a series of recommendations for their development. The main components of such systems, including ultrasound calibration and system interface design, as well as applications of AR-UIG systems for quantitative skill assessment, were also examined in this thesis. The effects of ultrasound image reconstruction techniques, as well as phantom material and geometry on ultrasound calibration, were investigated. Ultrasound calibration error was reduced by 10% with synthetic transmit aperture imaging compared with B-mode ultrasound. Phantom properties were shown to have a significant effect on calibration error, which is a variable based on ultrasound beamforming techniques. This finding has the potential to alter how calibration phantoms are designed cognizant of the ultrasound imaging technique. Performance of an AR-UIG guidance system tailored to central line insertions was evaluated in novice and expert user studies. While the system outperformed ultrasound-only guidance with novice users, it did not significantly affect the performance of experienced operators. Although the extensive experience of the users with ultrasound may have affected the results, certain aspects of the AR-UIG system contributed to the lackluster outcomes, which were analyzed via a thorough critique of the design decisions. The application of an AR-UIG system in quantitative skill assessment was investigated, and the first quantitative analysis of needle tip localization error in ultrasound in a simulated central line procedure, performed by experienced operators, is presented. Most participants did not closely follow the needle tip in ultrasound, resulting in 42% unsuccessful needle placements and a 33% complication rate. Compared to successful trials, unsuccessful procedures featured a significantly greater (p=0.04) needle-tip to image-plane distance. Professional experience with ultrasound does not necessarily lead to expert level performance. Along with deliberate practice, quantitative skill assessment may reinforce clinical best practices in ultrasound-guided needle insertions. Based on the development guidelines, an AR-UIG system was developed to address the challenges in ultrasound-guided epidural injections. For improved needle positioning, this system integrated A-mode ultrasound signal obtained from a transducer housed at the tip of the needle. Improved needle navigation was achieved via enhanced visualization of the needle in an AR environment, in which B-mode and A-mode ultrasound data were incorporated. The technical feasibility of the AR-UIG system was evaluated in a preliminary user study. The results suggested that the AR-UIG system has the potential to outperform ultrasound-only guidance

Toward forward-looking OCT needle tip vision of the spinal neuroforamen: animal studies

Neurologic complications have been reported with spinal transforaminal injections. Causes include intraneural injection, plus embolization occlusion of the radicular artery with subsequent spinal cord infarction. 1 Optical coherence tomography (OCT) is a non-invasive imaging modality, which is used to image tissue microstructure with very high resolution (less than 20 microns) in real-time. With a view toward needle tip OCT visualization of the spinal neuroforamen, we conducted animal studies to explore OCT imaging of paraspinal neurovascular structures. With institutional animal care committee approval, we performed ex-vivo and in situ OCT studies in a euthanized dog, pig, and rabbit. Image data was gathered on spinal nerve roots, dura, and brachial plexus. Two systems were used: frequency domain OCT imaging system developed at California Institute of Technology, and time domain Imalux NIRIS system with a 2.7 mm diameter probe. In a euthanized pig, excised dura was punctured with a 17-gauge Tuohy needle. FDOCT dural images of the puncture showed a subsurface cone-shaped defect. In a rabbit in situ study, puncture of the dura with a 26-gauge needle is imaged as a discontinuity. FDOCT imaging of both small artery and large arteries will be presented, along with H&E and OCT images of the brachial plexus

The state-of-the-art in ultrasound-guided spine interventions.

During the last two decades, intra-operative ultrasound (iUS) imaging has been employed for various surgical procedures of the spine, including spinal fusion and needle injections. Accurate and efficient registration of pre-operative computed tomography or magnetic resonance images with iUS images are key elements in the success of iUS-based spine navigation. While widely investigated in research, iUS-based spine navigation has not yet been established in the clinic. This is due to several factors including the lack of a standard methodology for the assessment of accuracy, robustness, reliability, and usability of the registration method. To address these issues, we present a systematic review of the state-of-the-art techniques for iUS-guided registration in spinal image-guided surgery (IGS). The review follows a new taxonomy based on the four steps involved in the surgical workflow that include pre-processing, registration initialization, estimation of the required patient to image transformation, and a visualization process. We provide a detailed analysis of the measurements in terms of accuracy, robustness, reliability, and usability that need to be met during the evaluation of a spinal IGS framework. Although this review is focused on spinal navigation, we expect similar evaluation criteria to be relevant for other IGS applications

Pain Management

This book has seven chapters, from more than 15 authors from different countries (Korea, Poland, Saudi Arabia, Taiwan, Turkey and USA) edited by Professor Milica Prostran MD, PhD. The potential reader is shown the modern approach to pain management because the chapters deal at length and clearly with their topics. I believe that this book that I edited with great pleasure and dedication will capture the attention of many readers, from medical students to practicing doctors. All of them need to deal with this extremely important field of medicine: pain treatment. I do believe that the answers they may find in Pain Management will make their practice easier. Also, the life of their patients will be considerably more pleasant, or at least more bearable

Opioid-free anesthesia—dexmedetomidine as adjuvant in erector spinae plane block: a case series

Background: Laparoscopic pain is related to the stretching of the peritoneum and peritoneal irritation caused by insufflation of the parietal peritoneum with carbon dioxide. In 2017, erector spinae plane block (ESPB) was described for management of postoperative pain following open and laparoscopic abdominal surgery. The use of multimodal anesthesia reduces both intraoperative and postoperative opioid use and improves analgesia. The addition of dexmedetomidine to the anesthetic mixture significantly prolongs analgesia, without clinically significant side effects. Case Presentation: We describe a series of three Caucasian women cases that illustrate the efficacy of bilateral ESPB performed at the level of the T7 transverse process to provide intraoperative and postoperative analgesia for laparoscopic gynecological surgery. Conclusion: Further investigation is recommended to establish the potential for ESPB with dexmedetomidine as adjuvant as an opioid-free anesthetic modality in laparoscopic gynecological surgery

Paresthesia

Paresthesias are spontaneous or evoked abnormal sensations of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. Patients generally describe a lancinating or burning pain, often associated with allodynia and hyperalgesia. The manifestation of paresthesia can be transient or chronic. Transient paresthesia can be a symptom of hyperventilation syndrome or a panic attack, and chronic paresthesia can be a result of poor circulation, nerve irritation, neuropathy, or many other conditions and causes. This book is written by authors that are respected in their countries as well as worldwide. Each chapter is written so that everyone can understand, treat and improve the lives of each patient

Perianesthesia analgesia, recovery efficacy, and financial impact of ultrasound-guided lumbar plexus and sciatic nerve analgesia in dogs undergoing tibial plateau leveling osteotomy

Includes bibliographical references.2022 Fall.Perioperative analgesia is critical for patients undergoing surgery because uncontrolled pain can result in deleterious consequences and predispose chronic pain. Therefore, developing an appropriate analgesia technique is crucial, and in this study, an analgesia protocol was investigated in dogs undergoing tibial plateau leveling osteotomy (TPLO). The TPLO is a surgical technique used to stabilize the stifle joint for treating cranial cruciate ligament disease. This surgical procedure is invasive and painful. Therefore, multimodal analgesia is often required for controlling pain associated with TPLO surgery. This study used ultrasound-guided regional anesthesia of the lumbar plexus and sciatic nerve as a component of multimodal analgesia to control perioperative pain compared to patients only receiving a standard systemic analgesia. The study was designed to evaluate the efficacy of regional anesthesia and to determine the financial impact of this additional multimodal procedure. We hypothesized that ultrasound-guided lumbar plexus and sciatic nerve blocks would provide a better analgesic effect intraoperative and postoperatively. The second part of the study we hypothesized that ultrasound-guided lumbar plexus and sciatic nerve blocks would increase the anesthesia cost. It would then be possible to determine a cost – benefit of the procedure. The study was designed as a prospective, randomized, blinded clinical trial. Twenty dogs underwent TPLO surgery were enrolled in the study and randomly assigned to regional analgesia (RA) or control (CON) group. Dogs in the RA group received 0.5% ropivacaine for ultrasound-guided lumbar plexus and sciatic nerve blocks. The total dose of ropivacaine for both blocks was 0.15 mg/kg. Dogs in the CON group received sterile 0.9% saline for the blocks. All dogs received 0.2 mg/kg of hydromorphone and 0.02 mg/kg of atropine for anesthesia premedication. Propofol was administered for anesthesia induction to perform endotracheal tube intubation. Isoflurane in oxygen was delivered using a circle rebreathing system to maintain anesthesia. The ultrasound-guided lumbar plexus and sciatic nerve blocks were performed prior to TPLO surgery. Fentanyl was used for intraoperative as rescue analgesia to reduce the response from surgical stimulation or with an increase in heart rate, respiratory rate, or mean arterial blood pressure. Isoflurane was adjusted to maintain the appropriate anesthesia plane. Hypotension was treated following a stepwise protocol, in a sequencing fashion. The treatment protocol was added until the complications was resolved. The treatment protocol started from decreased isoflurane vaporizer setting, lactate Ringer's solution bolus, hetastarch bolus, and dopamine administration. At extubation, the recovery quality and pain were evaluated. Dexmedetomidine was used to treat poor recovery quality and pain. During the postoperative 12 hours period, pain and recovery quality were assessed by Colorado State University acute pain scale, visual analog pain scale, and modified University of Melbourne pain scale. Fentanyl or methadone was used for postoperative rescue analgesia. Dexmedetomidine or acepromazine was administered to calm the patient. The amount of every drug used, complications management, and extra nursing care were recorded to evaluate the blocks' efficacy. The micro-costing technique was used to collect the financial data and was analyzed to determine the financial impact. In the clinical study, there was a statistically significant difference in the amount of intraoperative fentanyl administered for rescue analgesia between the groups (p = 0.02), with lesser doses given to the RA group. Hypotension was found in 40% of dogs in the RA group and 80% of the dogs in the CON group (p = 0.16). Dogs in the RA group required less intensive treatment than in the CON group. There was a statistically significant difference in the recovery scores between the groups, with those in the RA group having lower recovery scores (p = 0.04). In the postoperative period, the time to receive the first dose of rescue analgesia for dogs in the RA group was longer than dogs in the CON group (p=0.04). Micro-costing method was used for collecting the monetary information. The cost analysis was performed for evaluating the costs of dogs that received ultrasound-guided regional anesthesia with 0.5% ropivacaine and 0.5% sterile saline. The anesthesia fixed cost for the surgery was US$354. There was a statistically significant difference between the variable costs, with the RA group (US$82.65 (69.15-94.56); median (min-max)) having less anesthesia variable costs than dogs in the CON group (US$125.8 (55.23 to 156.35); p = 0.02). The additional cost for a charge per service of the use of ultrasound and electro-nerve stimulator machines (US$26.62) affects the total anesthesia cost for the RA group into both direction, it can enhance and save the total anesthesia cost. It can increases the total anesthesia cost by $US40.54 per dog and it can save the total anesthesia cost by$US35.17 per dog. From the clinical perspective, the number of dogs receiving TPLO surgery at the study hospital is approximately 160 cases per year. This number was used for estimating cost benefit per year performing nerve blocks for TPLO surgery and found that the nerve blocks would potentially increase the total cost for 160 dogs to US$6,486.40 per year but would decrease the total anesthesia cost by US$5,627.20 per year. Ultrasound-guided lumbar plexus and sciatic nerve regional analgesia was found to be an effective multimodal analgesia for TPLO surgery. The technique provided effective intraoperative analgesia that decreased rescue analgesia during surgery and led to better recovery from anesthesia for the dogs in this study. The ultrasound-guided analgesia technique would increase anesthesia costs but better analgesia, anesthesia, and decreased complications provided significant cost-saving benefits when performing regional analgesia for TPLO surgery