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Background Indications for a minimally invasive resections are increasing worldwide, but respecting anatomical planes during intraparenchymal transection is demanding. Intraoperative ICG fluorescence staining of liver parenchyma has been introduced as a tool for real-time intraoperative guidance. The aim of this study is to make a systematic review of the current relevant literature on indications, techniques, and results of laparoscopic anatomical liver resection (LALR) using intraoperative indocyanine green (ICG) fluorescence for positive and negative staining of liver segments in patients affected by liver malignancies. Methods Electronic bibliographical databases (MEDLINE and PubMed) were searched according to the PRISMA criteria. English language articles meeting the selection criteria and published until June 2020 were retrieved and reviewed. Results a total of 86 articles were initially found and 11 articles were finally included in the analysis with a total of 83 patients treated. Sixty-two patients (74.6%) underwent mono-segmentectomies. Thirty-five patients (42.1%) underwent the positive staining technique, and forty-eight patients (57.8%) the negative staining technique. Conclusions The positive or negative indocyanine green staining technique with real-time fluorescence guidance is an emerging and promising approach. However, the technique has to be standardized and advantages in terms of oncologic results still need validation in further studies.

The role of engineering technologies in various aspects of human health and well-being is expanding at a remarkable rate. Whether it’s in routine health screening, diagnostics, monitoring, intraoperative guidance, delivery of treatments, drug and vaccine discovery, or just lifestyle enhancement, the ever-increasing importance of engineering technology is undeniable. In particular, devices and techniques that take advantage of electromagnetics (EM) principles are among the key enablers of medical technologies, providing otherwise-unavailable methods for information collection, information transmission, and treatment and intervention. The areas of influence of EM are numerous; we are not just talking about microwave imaging, which is perhaps one of the earliest applications of EM in biomedicine. There are many other innovative application areas that have emerged in the recent past, including implantable devices, new antenna materials for enhancing traditional applications, wireless power transfer, wearables, and the like.

The use of preoperative and intraoperative guidance in foot and ankle surgery has grown substantially in recent years. Weight-bearing computed tomography (WBCT) and patient-specific instrumentation (PSI) are used in total ankle arthroplasty (TAA) to achieve precise bone cutting and implant positioning, and intraoperative 3-dimensional (3D) imaging has been used to reduce complications and improve clinical outcomes in other foot and ankle surgical procedures. This narrative review of the literature focuses on the evidence supporting the use of WBCT and PSI in TAA and looks at other promising technologies used to guide foot and ankle surgery.

While 3D printing is adapted usefully in certain field of surgery, its application in liver surgery was limited. Here, we introduce our experience for using 3D printing for intraoperative guidance during liver resection in a case for HCC with an intrahepatic metastasis at a sophisticated location. A 50 years old male patient was diagnosed 4.7 cm-sized hepatocellular carcinoma located on segment 3 with and an intrahepatic metastasis located on segment 8 which was between right anterior portal vein, middle hepatic vein and right hepatic vein. Since radiofrequency ablation appeared to be inappropriate, surgical resection was planned. However, the patient had a cirrhotic liver and left liver was estimated to be 47% according to volume measurement. Therefore, we planned a two-step procedure by performing left hemihepatectomy preserving the middle hepatic vein and additionally removing the intrahepatic metastasis by tumorectomy. For better guidance, we made a 3D printed model tailored for using it as a guidance during operation, and the accuracy of 3D-printed model helped the surgical team perform a safe operation. The patient underwent adjuvant proton beam therapy on the site of tumorectomy and did not experience recurrence.

PURPOSE: To assess the use of the new Focal-One(®) HIFU platform in salvage setting to evaluate the occurrence of postoperative complications. METHODS: Patients who underwent salvage HIFU (sHIFU) with Focal-One(®) platform were enrolled prospectively (Candiolo cancer institute—FPO IRCCS; registry number: 258/2018). Perioperative and postoperative outcomes (in terms of oncological and functional ones) were recorded during the first year of follow-up. In particular postoperative complications were classified according to Clavien–Dindo system. RESULTS: 20 patients were enrolled. No grade 3 complications were recorded. Referring to grade 2 complications, eight patients reported urgency after 3 months of follow-up, and in 4 cases, a low urinary tract infection occurred. Evaluating the impact of sHIFU on patients’ sexual potency, micturition and quality of life, no significant deterioration was recorded during the follow-up as proven using the ANOVA analysis for repeated measurements. Only two patient had a biochemical failure after 12 months of follow-up. CONCLUSIONS: The real-time intraoperative guidance with Focal-One(®) platform, allows a continuous monitoring and tailoring of the treatment, with a minimization of the adverse events even in a salvage setting. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40477-021-00594-8.

Residual femoroacetabular impingement syndrome due to incomplete resection of a cam deformity is the leading cause of failed hip arthroscopy. The reliability of the alpha angle has been shown for quantifying cam deformities in femoroacetabular impingement syndrome. An intraoperative navigation tool that provides the ability to compare alpha angle measurements side by side on pre- and post-resection fluoroscopic images has recently been introduced. This tool uses fluoroscopic images obtained in 6 different hip positions. The reliability of these standardized hip positions has been shown by correlation with computed tomography in localization and visualization of cam deformities. The purpose of this Technical Note is to give technical tips about the application of this tool., Technique Video Video 1 Key aspects of hip arthroscopy in right hip with patient in supine position with intraoperative navigation tool based on alpha angle measurement. The navigation monitor is placed below the level of the arthroscopy monitor and between the C-arm and arthroscopy monitor so that it does not disrupt the existing operating room setup. Once joint distraction of nearly 1 cm is observed, the anterolateral portal and then the modified midanterior portal are created. An interportal capsulotomy is performed between these portals. In this right-sided hip arthroscopy, after the distal anterolateral portal is created, 3 anchors are placed at the 12-, 1-, and 2-o’clock positions. For the labral repair, sutures are passed and tied accordingly with the aid of arthroscopic instruments. Next, traction is released, a T-capsulotomy is made through the distal anterolateral portal, and suspension sutures are passed through each side of the capsule for a better vantage. To start the HipCheck application, the surgeon identifies the femoral head and neck on a random fluoroscopic image on the navigation touchscreen. Before osteochondroplasty is started, pre-resection measurements are obtained in 6 different hip positions with the HipCheck system. During the procedure, the amount of resection can be instantly checked by taking fluoroscopic images in the desired hip positions at any time. When the cam resection is considered adequate, the 6 fluoroscopic images obtained before resection are obtained once more in the same order, and the new alpha angle values are recorded as the post-resection measurements. Finally, the capsule is closed.

Objective: Surgical planning for robotic-assisted partial nephrectomy is widely performed using two-dimensional computed tomography images. It is unclear to what extent two-dimensional images fully simulate surgical anatomy and case complexity. To overcome these limitations, software has been developed to reconstruct three-dimensional models from computed tomography data. We present the results of a feasibility study, to explore the role and practicality of virtual three-dimensional modelling (by Innersight Labs) in the context of surgical utility for preoperative and intraoperative use, as well as improving patient involvement. Methods: A prospective study was conducted on patients undergoing robotic-assisted partial nephrectomy at our high volume kidney cancer centre. Approval from a research ethics committee was obtained. Patient demographics and tumour characteristics were collected. Surgical outcome measures were recorded. The value of the three-dimensional model to the surgeon and patient was assessed using a survey. The prospective cohort was compared against a retrospective cohort and cases were individually matched using RENAL (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, location relative to polar lines) scores. Results: This study included 22 patients. Three-dimensional modelling was found to be safe for this prospective cohort and resulted in good surgical outcome measures. The mean (standard deviation) console time was 158.6 (35) min and warm ischaemia time was 17.3 (6.3) min. The median (interquartile range) estimated blood loss was 125 (50–237.5) ml. Two procedures were converted to radical nephrectomy due to the risk of positive margins during resection. The median (interquartile range) length of stay was 2 (2–3) days. No postoperative complications were noted and all patients had negative surgical margins. Patients reported improved understanding of their procedure using the three-dimensional model. Conclusion: This study shows the potential benefit of three-dimensional modelling technology with positive uptake from surgeons and patients. Benefits are improved perception of vascular anatomy and resection approach, and procedure understanding by patients. A randomised controlled trial is needed to evaluate the technology further. Level of evidence: 2b

Artificial intelligence (AI) is gradually changing the practice of surgery with technological advancements in imaging, navigation, and robotic intervention. In this article, we review the recent successful and influential applications of AI in surgery from preoperative planning and intraoperative guidance to its integration into surgical robots. We conclude this review by summarizing the current state, emerging trends, and major challenges in the future development of AI in surgery.

This paper describes a method for setting up an automated and reliable digital profileplasty technique for use in Adobe Photoshop. Digital imaging software can be used to extrapolate more exact measurements during profileplasty. The digital profileplasty technique is helpful to provide intraoperative guidance during surgery.

Dermal filler injections, one of the most commonly performed procedures in facial esthetic surgery, are rising in popularity. This has also led to an increase in nonmedical grade filler injections performed by nonmedical personnel, including that of injectable silicone. Surgical removal of silicone fillers is challenging, as the hydrophobic material often disperses within the soft tissue as droplets. This can lead to a systemic inflammatory reaction requiring steroid treatment. MRI localization of the filler material does not enable intraoperative guidance, and palpitation of the material is challenging since the filler droplets are often too small to palpate and located in multiple planes. We present a case demonstrating the advantages of utilizing intraoperative ultrasound to localize and silicone filler material. Utilizing this technique, we were able to achieve a high degree of excision of silicone filler material and the patient was able to stop her previous necessary immunosuppressive steroid regimen successfully.

Robotic assistance in surgical procedures is a valuable tool that enhances the safety and efficacy of invasive surgeries. These devices are divided functionally into surgeon surrogates where the device operates under the direct control of an offsite surgeon, and surgeon adjuncts where the device is an intraoperative guidance tool used in a portion of the procedure. The current state of robotic spine surgery focuses on the latter, addressing the primary task of pedicle screw placement. We would like to share our experience with the Mazor Robotics devices to discuss the underlying concepts, strengths, weaknesses, and results as they pertain to pediatric spine deformity.

Hyperspectral imaging (HSI) is a novel optical imaging modality, which has recently found diverse applications in the medical field. HSI is a hybrid imaging modality, combining a digital photographic camera with a spectrographic unit, and it allows for a contactless and non-destructive biochemical analysis of living tissue. HSI provides quantitative and qualitative information of the tissue composition at molecular level in a contrast-free manner, hence making it possible to objectively discriminate between different tissue types and between healthy and pathological tissue. Over the last two decades, HSI has been increasingly used in the medical field, and only recently it has found an application in the operating room. In the last few years, several research groups have used this imaging modality as an intraoperative guidance tool within different surgical disciplines. Despite its great potential, HSI still remains far from being routinely used in the daily surgical practice, since it is still largely unknown to most of the surgical community. The aim of this study is to provide clinical surgeons with an overview of the capabilities, current limitations, and future directions of HSI for intraoperative guidance.

Surgical data science (SDS) and computer-assisted surgery (CAS) are becoming increasingly conventional as more physicians incorporate surgical navigation systems into their workflows. Consequently, the necessity for enhanced anatomical structure depictions during intraoperative surgical guidance is also increasing. Anatomically accurate musculoskeletal representations are particularly necessary for orthopedic operations, especially spinal procedures. Additionally, CAS system recognition of clinically relevant structures along surgical corridors is of equal importance; such recognition permits intraoperative guidance when procedures are supervised by surgical process models (SPMs). Therefore, this study outlines a comprehensive solution, termed the “Surgical GPS”, which merges patient-specific, ligamentoskeletal models and physician-designated landmarks and ontologies, to expand spinal anatomy representations and demonstrate SPM applications toward several spine procedures. Patient models are validated with Dice similarity coefficient and Hausdorff distance metrics. Anatomical landmarks are queried from SPMs using pertinent search engines and are highlighted on the patient models, potentially enhancing successful surgical outcomes through context-aware, “GPS” guided CAS.

Transcatheter aortic valve implantation (TAVI) is widely accepted as an alternative to surgical aortic valve replacement (SAVR) for the treatment of severe aortic stenosis (AS). Existing scientific evidence demonstrates that TAVI is superior to SAVR, and it is expected that indications for the clinical applications of TAVI will be expanded in the future. Echocardiography plays a key role in perioperative assessment of patients undergoing TAVI. Preprocedural echocardiographic evaluation is important to determine the severity of AS in addition to patients' anatomical suitability for TAVI. Furthermore, echocardiography is essential for intraoperative guidance, assessment of complications, postoperative evaluation, and prognostic prediction. Inaccurate echocardiographic measurements and evaluation can lead to less-than-optimal/inappropriate treatment strategies in patients with AS. Therefore, a thorough understanding of the limitations of echocardiographic evaluation is important. This review summarizes the role of echocardiographic evaluation in patients undergoing TAVI.

Purpose: Radio-frequency ablations play an important role in the therapy of malignant liver lesions. The navigation of a needle to the lesion poses a challenge for both the trainees and intervening physicians. Methods: This publication presents a new GPU-based, accurate method for the simulation of radio-frequency ablations for lesions at the needle tip in general and for an existing visuo-haptic 4D VR simulator. The method is implemented real-time capable with Nvidia CUDA. Results: It performs better than a literature method concerning the theoretical characteristic of monotonic convergence of the bioheat PDE and a in vitro gold standard with significant improvements (p < 0.05) in terms of Pearson correlations. It shows no failure modes or theoretically inconsistent individual simulation results after the initial phase of 10 seconds. On the Nvidia 1080 Ti GPU it achieves a very high frame rendering performance of >480 Hz. Conclusion: Our method provides a more robust and safer real-time ablation planning and intraoperative guidance technique, especially avoiding the over-estimation of the ablated tissue death zone, which is risky for the patient in terms of tumor recurrence. Future in vitro measurements and optimization shall further improve the conservative estimate., 18 pages, 14 figures, 1 table, 2 algorithms, 2 movies

The intraoperative fluoroscopy has been widely used in modern neuro-spinal surgery due to the overwhelming trend toward minimal-access surgery. However, both patients and surgical personnel were under ionizing-radiation exposure during fluoroscopy usage. Since the fluoroscopy constitutes the vast majority of radiation exposure for both surgeons and patients, the development and improvement of new interventional possibilities are of great importance and interests.A total of 20 patients were included in the current study, who received thoracic-spinal tumor resection via posterior midline approach. In comparison to the conventional C-Arm mobile fluoroscopy machine, the Surgical Approach Visualization and Navigation (SAVN) System was used to evaluate the effectiveness in reducing radiation.The pain intensity and Japanese Orthopedic Association Score were equally ameliorated in patients of two groups. However, compared to C-arm group, the SAVN significantly reduced the screening time from 26.8 + 12.4 to 17.1 + 9.2 s (36.2% radiation reduction, P 0.05), which was mainly due to the significant reduction of radiation attempts (from 12.8 + 4.9 to 7.1 + 5.5 times, P 0.05). For patients, the direct and scatter radiation dose dropped 30.4% (P 0.05) in the surgical region and 47.6% (P 0.01) in the non-surgical region by using the SAVN System. Additionally, the tumor diameter/skin incision ratio increased from 0.39 + 0.4 to 0.47+ 0.28 after SAVN usage. Meanwhile, thedosimeter showed that the radiation dose to the primary surgeon was also lower in the SAVN group (72.1% reduction, P 0.01).Comparing the conventional C-arm, the SAVN System based thoracic-spinal surgery significantly lowered radiation duration and dosage application towards both surgeons and patients.

Combining electromagnetic tracking of instruments with preoperatively acquired images can provide detailed visualization for intraoperative guidance and reduce the need for fluoroscopy and contrast. In this study, we investigated the accuracy of a vessel-based registration method designed for matching preoperative image and electromagnetically tracked positions for endovascular therapy.An open-source registration method was used to match the centerline extracted from computed tomography (CT) to electromagnetically tracked positions within a vascular phantom representing the abdominal aorta with bifurcations. The target registration error (TRE) was calculated for 11 fiducials distributed over the phantom. Median and intra-quartile range (IQR) for 30 registrations was reported. TRE5 mm was claimed sufficient for endovascular navigation, evaluated using the Wilcoxon signed-rank test. TRE was also compared to a 3D-3D registration method based on intraoperative cone-beam CT, using the Mann-Whitney U-test.The TRE was 3.75 (IQR: 3.48-3.99) mm for the centerline registration algorithm and 3.21 (IQR: 1.50-3.57) mm for the 3D-3D method (p .001). For both methods, the TRE was significantly5 mm (p .001).The centerline registration method was feasible, with an accuracy sufficient for navigation in endovascular therapy. The centerline method avoids additional image acquisition for registration purpose only.

The interest and potential use of augmented reality (AR) in several medical fields since the early 90′s has increased consistently. It provides intraoperative guidance for surgical procedures by rendering visible what cannot be seen directly, possibly affecting surgical outcomes. Our objective was to conduct a systematic review of the intraoperative clinical application of augmented reality in neurosurgery, in studies published during the last five years. We carried out an electronic search in the PUBMED database using the terms “Augmented Reality” and “Neurosurgery.” After exclusions, 12 published articles that evaluated the utility of intraoperative clinical applications in surgical settings were included in our review. The results evaluated involved AR technique and visualization, time, complications, projection error, and located structures. We can conclude that the neurovascular application is the most frequent type of use for AR in neurosurgery (47.3%), followed by applications in neuro-oncological pathologies (46.7%), and non-vascular and non-neoplasic lesions (5.9%). The use of AR also allows a surgeon to maintain their view on the operative site permanently, and is useful for locating structures, guiding resections, and planning the craniotomy with more precision, decreasing the risk of injury. The intraoperative application of an augmented reality system helps to improve the quality and characteristics of the surgical field image. The injection of 3D images with AR allows for the successful integration of images in vascular, oncological and other lesions without the need of look away from the surgical field, improving safety, surgical experience, or clinical outcome. However, comparative studies are still required to determine its effectiveness.

Positron-emitting radioactive isotope-labeled gold nanomaterials are suitable imaging agents in biomedical imaging owing to their high sensitivity, straightforward clinical translation, adequate information regarding clinical safety, and their application in another new imaging modality, Cerenkov luminescent imaging. This study aimed to investigate the potential application of PEGylated crushed gold shell @ radioiodine-labeled core nanoparticles (PEG-124I-Au@AuCBs) in detecting sentinel lymph nodes (SLNs) in mice in vivo, using the dual imaging modality of positron emission tomography and Cerenkov luminescence imaging (PET/CLI). PEG-124I-Au@AuCBs were non-toxic and did not affect cellular function in normal and immune cells. In vivo PET imaging revealed the selective accumulation of PEG-124I-Au@AuCBs in SLNs proximal to the site of injection 1 h after injection and radioactivity was detected from the SLN until 24 h. Consistently, the SLNs were also visualized using in vivo CLI at 24 h, consistent with the findings of ex vivo bio-distribution and histological analyses. Therefore, PEG-124I-Au@AuCBs are suitable multimodal contrast agents for in vivo SLN mapping in pre- or intraoperative guidance.

Introduction Previous data examining the effect of gender on surgical trainee autonomy is lacking. We hypothesized that female general surgery residents have less autonomy than males during laparoscopic cases. Methods We retrospectively reviewed factors associated with level of guidance needed during laparoscopic procedures as reported on intraoperative procedure feedback forms and on FLS tasks from one institution from 2013 to 2016. Data collected included resident and attending gender, level of guidance needed, PGY level, case characteristics, resident intraoperative performance, and skills lab FLS performance. Univariate and multivariate analyses were performed using a mixed-effects regression model. Results We analyzed data from 106 PGY1-PGY5 residents (51% Female) and 104 attendings (26% Female). Female resident gender was associated with more intraoperative guidance in univariate (p = 0.019) and multivariate analysis (p = 0.034). Technical performance between genders was similar. Conclusions This study demonstrated gender-based inequality in intraoperative autonomy even after controlling for technical performance, PGY level, and case factors.

REPLY: We would like to thank Dr. Mariani et al. ([1][1]) for their letter highlighting important papers on sentinel node imaging and intraoperative guidance. These papers are noteworthy scientific contributions that continue to have a significant impact on the clinical practice of nuclear medicine

Positron emission tomography-computed tomography (PET-CT) performed with new radiopharmaceuticals has revolutionized the imaging area in prostate cancer (Pca). 68Ga/18F-labeled prostate-specific membrane antigen (PSMA) has been the most promising radiotracer for staging and restaging of Pca. PSMA-based imaging outperformed conventional imaging (CI) in restaging and has a high clinical impact in patient management. Recently introduced 99mTc-labeled-PSMA compounds provide intraoperative guidance, which improved surgical outcomes of salvage surgical therapy. This chapter mainly focuses on PSMA-based imaging and discuss the potential benefits and limitations.

Virtual reality (VR) technology has existed for decades, and the promise for its groundbreaking applications to healthcare has been discussed for almost as long. Recent advances in computer technology and decreasing costs of VR hardware have now allowed this technology to become increasingly utilized in the medical and healthcare industries. Additionally, newer technologies such as augmented reality promise additional benefit to patients and clinicians. By creating immersive and realistic environments, these technologies can be used as medical education tools for clinicians and patients, visualization tools for surgical planning and intraoperative guidance, and therapeutic tools for a wide range of health problems.

With advances in anatomical knowledge and technology, increased interest has been directed towards reconstruction with enhanced aesthetic and functional outcomes. A myriad of thinned perforator flap harvest approaches have been developed for this purpose; however, concerns about jeopardizing their vascularity remain. To ensure optimum reconstructive outcome without hampering the flap’s microcirculation, it is important to make good use of the existing advanced imaging modalities that can provide clear visualization of perforator branches, particularly in the adipose layer, and an accurate assessment of flap perfusion. Therefore, this review will highlight the imaging modalities that have been utilized for harvesting a thinned perforator flap from these two perspectives, along with future insights into creating both functionally and aesthetically satisfying, yet simultaneously safe, thinned perforator flaps for the best reconstructive outcomes for patients.

Pathology is finally profiting from the recent development of promising novel imaging techniques, as well as exploration of computational methods for extracting increased information from existing slides and conventional microscopy. This chapter focuses largely on the latter, looking at application of artificial intelligence (AI) methods for denoising, sharpening, super-resolution, and color mapping from unstained slides to generate virtually stained images. In addition, software-based tools have been developed to replicate histochemical and immunohistochemical results without having to perform the actual procedures. Finally, an example of an application of novel slide-free histology using stimulated Raman microscopy for intraoperative guidance during brain cancer surgery is presented remarkably; this method includes AI classification tools (cancer/not cancer) that surgeons can rely on directly.

The Perihilar area is a complex region where bile ducts, portal veins, hepatic arteries, lymphatics, and nerves intertwine often in an unpredictable way. Anatomical variation is common and the spatial relationships between the vessels are difficult to predict. Imaging techniques greatly assist the surgeon in visualizing the individual anatomy, improving operative precision, patient safety, and shortening duration of surgery. This chapter outlines the characteristic anatomical variation and spatial relationships between the portal veins, hepatic arteries, and bile duct. It categorizes: perihilar diseases and discusses their impact on the hilum, atrophy, and hypertrophy of the liver lobes. We discuss the nature of invasive disease and concomitant difficulties during surgery. We also outline the treatment of disease, and the value of imaging technologies, modeling hepatic lobe segmentation and related vasculature to enable simulated surgery, and for precise preoperative and intraoperative guidance. The chapter closes with a description of the 3D imaging software systems, from image acquisition, and data migration to 3D modelling of the perihilar region and the liver.

Zygomatic implants (ZIs) have been used successfully for the rehabilitation of jaws with severe atrophy for the past 2 decades. The development of computed tomography, three-dimensional (3D) analysis software, and stereolithographic models has positively impacted the development of preoperative planning. This article describes the protocol developed by the Department of Oral and Maxillofacial Surgery of El Bosque University, Bogota, Colombia, through 10 years of experience, for the installation of ZIs, covering from the times when the implants were placed through intraoperative guidance, until now, in which drilling guides developed by computer-aided design and computer-aided manufacturing are used, without neglecting in their design multiple factors that must be considered. To date, this protocol for the treatment of patients with atrophic jaws through ZIs includes a detailed clinical examination, in which variables such as bone and dental relationship between the jaws, oral opening and dynamic interaction between soft cervicofacial tissues are considered. It also includes a 3D computed tomography planning for the design and preparation of surgical guides whose insertion patterns must be executable during surgery. Together, clinical and imaging analysis converge in what it has been called morpho-functional 3D planning.

Intraoperative optical coherence tomography (iOCT) enables real-time visualization of ocular structures during surgery and enhances our understanding of intraoperative dynamics. iOCT aids in decision-making during various anterior segment surgeries, and its efficacy and feasibility in anterior lamellar keratoplasty and endothelial keratoplasty is well established. The landmark DISCOVER study observed that iOCT altered the surgeon decision in 38% of cases undergoing lamellar keratoplasty and provided guidance regarding the need for secondary surgical intervention. iOCT also finds an application in phacoemulsification wherein it helps to assess corneal incisions, intralenticular pressure, and posterior capsule integrity during nuclear emulsification. iOCT aids in the visualization of angle structures during placement of tubes and shunts in glaucoma surgeries and allows precise creation of partial thickness scleral flaps. In addition, iOCT helps in establishing a diagnosis, as well as provide intraoperative guidance, in pediatric patients who are not cooperative for examination. The role of iOCT in refractive surgeries and ocular surface disorders is increasingly being evaluated. The limitations of present-day iOCT systems are related to instrument compatibility, automated tracking of the surgical field, and on-table volumetric analysis of the real-time images. Technological advances may facilitate complete integration of OCT in the surgical microscopes for all surgical procedures.

Cardiac computed tomography (CT) is increasingly used to plan transcatheter structural heart interventions. However, intraoperative guidance relies on transesophageal echocardiography (TEE) and fluoroscopy. This study sought to develop a stepwise CT multi-planar reconstruction manipulation method to mimic TEE, bridging the gap between preoperative planning and intraoperative guidance tools. This CT manipulation reproduced similar configurations as TEE views in the mid-esophageal left ventricle (LV) views, transgastric LV 2-chamber views for mitral apparatus, and other miscellaneous views. Stepwise cardiac CT manipulation to mimic TEE is the final piece of the puzzle in the mental co-registration of these three crucial imaging modalities. Now, we can predict the TEE images and fluoroscopy projections in a preoperative rehearsal, thus improving the intraoperative accuracy of interventions.

Real-time visualization of imaging data constitutes a critical part of surgical workflow. Augmented reality (AR) is a promising tool to assist in conventional surgical navigation systems. We have been developing an AR framework for clinical imaging and guidance using an optical see-through head-mounted display (OST-HMD) and fluorescence lifetime imaging (FLIm) instrumentation. This framework supports in vivo scanning of FLIm data and the real-time visualization of diagnostic information overlaid on the interrogated tissue area. With the high discriminative power of FLIm, our FLIm-AR concept has the potential for indicating tumor margins and assisting with tumor excision surgery.

5-ALA-based fluorescence-guided surgery has been shown to be a safe and effective method to improve intraoperative visualization and resection of malignant gliomas. However, it remains ineffective in guiding the resection of lower-grade, non-enhancing, and deep-seated tumors, mainly because these tumors do not produce detectable fluorescence with conventional visualization technologies, namely, wide-field (WF) surgical microscopy. We describe some of the main factors that limit the sensitivity and accuracy of conventional WF surgical microscopy, and then provide a survey of commercial and research prototypes being developed to address these challenges, along with their principles, advantages and disadvantages, as well as the current status of clinical translation for each technology. We also provide a neurosurgical perspective on how these visualization technologies might best be implemented for guiding glioma surgeries in the future. Detection of PpIX expression in low-grade gliomas and at the infiltrative margins of all gliomas has been achieved with high-sensitivity probe-based visualization techniques. Deep-tissue PpIX imaging of up to 5 mm has also been achieved using red-light illumination techniques. Spectroscopic approaches have enabled more accurate quantification of PpIX expression. Advancements in visualization technologies have extended the sensitivity and accuracy of conventional WF surgical microscopy. These technologies will continue to be refined to further improve the extent of resection in glioma patients using 5-ALA-induced fluorescence.

In patients with supratentorial lesions diffusion tensor imaging fiber tracking (DTI-FT) is increasingly used to visualize subcortical fiber courses. Navigated transcranial magnetic stimulation (nTMS) was applied in this study to reveal specific cortical functions by investigating the particular language errors elicited by stimulation. To make DTI-FT more function-specific, the identified language-positive nTMS spots were used as regions of interest (ROIs). In this study 40 patients (mean age 53.8 ± 16.0 years) harboring language-eloquent left hemispheric lesions underwent preoperative nTMS language mapping. All induced error categories were separately defined as a ROI and used for function-specific nTMS-based DTI-FT. The fractions of patients showing various subcortical language-related pathways and the fibers-per-tract ratio (number of visualized fibers divided by the number of visualized tracts) were evaluated and compared for tractography with the single error types against less specific tractography including all identified cortical language sites (all errors except hesitations). The nTMS-based DTI-FT using all errors except hesitations led to high fractions of visualized tracts (81.1% of patients), with a fibers-per-tract ratio of 538.4 ± 340.5. When only using performance errors, a predominant visualization of the superior longitudinal fascicle (SLF) occurred, which is known to be involved in articulatory processes. Fibers-per-tract ratios were comparatively stable for all single error categories when compared to all errors except hesitations (p > 0.05). This is one of the first studies aiming on function-specific tractography. The results demonstrated that when using different error categories as ROIs, more detailed nTMS-based DTI-FT and, therefore, potentially superior intraoperative guidance becomes possible.

PURPOSE: In breast-conserving surgery (BCS), the cancer is sometimes incompletely excised, leading to reduced patient survival. To pursue complete excisions, radioactive seed localization (RSL) may be used to insert an iodine-125 seed into the tumor. The seed is used as a marker for the location of the tumor during surgery. RSL does not, however, show the extent of the tumor. Based on RSL, we pursue to visualize the seed location together with the tumor extent from diagnostic images. METHODS: A system with two gamma camera heads and two parallel-hole collimators was recently proposed to triangulate the location of an iodine-125 seed during BCS. In the present study, this system was extended with a range camera to visualize a sphere centered on the seed in relation to the breast. This sphere contains the entire tumor and thus defines the target volume for BCS. Physical experiments with acrylic block phantoms (thickness ranging from 3.5 to 6.5 cm) were performed to assess the absolute bias and the precision with which this sphere can be visualized. RESULTS: When a 6.5 cm thick phantom was used, along the horizontal plane, the target volume was visualized with an absolute bias and a precision of 2.1 mm and 0.8 mm, respectively. Along the vertical axis (i.e., Z-axis), these values were 4.2 mm and 2.8 mm, respectively. CONCLUSIONS: The proposed system visualizes the target volume with an absolute bias that may be acceptable for BCS. This article is protected by copyright. All rights reserved.

Background Kommerell's diverticulum is a complex congenital malformation of aorta. Three-dimensional (3D) printing is an innovative manufacturing process that allows computer-assisted conversion of 3D imaging data into physical "printouts." The aim of this study was to explore the feasibility and impact of using patient-specific 3D-printed cardiac prototypes derived from computed tomography data on surgical decision-making and preoperative planning for Kommerell's diverticulum. Methods From April to August 2017, five patients with Kommerell's diverticulum were diagnosed and chosen for study. Cardiac computed tomography was done for all patients. One case was diagnosed with left aortic arch, and another four cases presented right-sided aortic arch and aberrant left subclavian artery. In addition, one patient complicated with aortic dissection. Data were used to generate patient-specific 3D models. All cases were reviewed along with their models, and the impact on surgical decision-making and preoperative planning was assessed. Results Accurate life-sized 3D models were successfully printed for all patients. These models enabled improved understanding of aortic malformation and preoperative planning. 3D models also allowed real-time intraoperative guidance for surgeons. Conclusions 3D printed models can improve the understanding of anatomy and allow anticipation of surgical technique challenges, which could radically assist surgical planning, and safe execution of surgery for Kommerell's diverticulum. The combination of 3D printing technique and surgical procedure is a promising perspective for treatment of complex aortic malformation.

Purpose: The aims of this review are to determine the feasibility of near-infrared fluorescence (NIRF) angiography in anastomotic colorectal surgery and to determine the effectiveness of the technique in improving imaging and quantification of vascularization, thereby aiding in decision making as to where to establish the anastomosis.Methods: A systematic literature search of PubMed and EMBASE was conducted. Searching through the reference lists of selected articles identified additional studies. All English language articles presenting original patient data regarding intraoperative NIRF angiography were included without restriction of type of study, except for case reports, technical notes, and video vignettes. The intervention consisted of intraoperative NIRF angiography during anastomotic colorectal surgery to assess perfusion of the colon, sigmoid, and/or rectum. Primary outcome parameters included ease of use, added surgical time, complications related to the technique, and costs. Other relevant outcomes were whether this technique changed intraoperative decision making, whether effort was taken by the authors to quantify the signal and the incidence of postoperative complications.Results: Ten studies were included. Eight of these studies make a statement about the ease of use. In none of the studies complications due to the use of the technique occurred. The technique changed the resection margin in 10.8% of all NIRF cases. The anastomotic leak rate was 3.5% in the NIRF group and 7.4% in the group with conventional imaging. Two of the included studies used an objective quantification of the fluorescence signal and perfusion, using ROIs (Hamamatsu Photonics) and IC-Calc® respectively.Conclusions: Although the feasibility of the technique seems to be agreed on by all current research, large clinical trials are mandatory to further evaluate the added value of the technique.

Laparoscopic liver resections have gained widespread popularity among hepatobiliary surgeons and is nowadays performed for both standard and more complex hepatectomies. Given the increased technical challenges, preoperative planning and intraoperative guidance is pivotal in laparoscopic surgery to safely carry out complex and oncologically safe hepatectomies. Modern tools can help both preoperatively and intraoperatively and allow surgeons to perform more precise hepatectomies. Preoperative 3D reconstructions and printing as well as augmented reality can increase the knowledge of the specific anatomy of the case and therefore plan the surgery accordingly and tailor the procedure on the patient. Furthermore, the indocyanine green retention dye is an increasingly used tool that can nowadays improve the precision during laparoscopic hepatectomies, especially when considering anatomical resection. The use of preoperative modern imaging and intraoperative indocyanine green dye are key to successfully perform complex hepatectomies such as laparoscopic parenchymal sparing liver resections. In this narrative review, we discuss the aspects of preoperative and intraoperative tools that are nowadays increasingly used in experienced hepatobiliary centers.

Spinal surgery carries an inherent risk of injury to the neural elements. Real-time intraoperative guidance such as neuromonitoring can substantially improve the safety and efficacy of spinal surgery.[1][1] A 32-year-old man, case of cervical spondylotic myelopathy (CSM), Nurick’s grade 3 with

Background: The existing Intraoperative MRI (IMRI) of developed countries is too costly to be affordable in any developing country and out of the reach of common and poor people of developing country at remote areas. We have used the pre-existing (refurbished) 3 side open “C” shaped 0.2 Tesla MRI for IMRI in a very remote area. Materials and Methods: In this technique the 0.2 Tesla MRI and the operating theatre were merged. MRI table was used as an operation table. We have operated 36 cases via IMRI from November 2005 to till date. First case operated was on 13th nov 2005. Results: Low (0.2) Tesla open setup costs very low (around Rs 40 lakhs) so highly affordable to management and thus to patients, used for diagnostic and therapeutic purposes both, the equipments like Nitrous, oxygen and suction is outside the MRI room so no noise inside operative room, positioning the patient didn't take much time due to manual adjustments, no special training to nurses and technicians required because of low (0.2) Tesla power of magnet and same instruments and techniques, sequencing took only 1.31 mints per sequence and re registration is not required since we always note down the two orthogonal axis in x and y axis in preoperative imaging and we were able to operate on posterior fossa tumors as well because of no head fixation except with leucoplast strap. Moreover the images we got intraoperative are highly acceptable. Conclusion: Three side open 0.2 Tesla MRI system, if used for intraoperative guidance, is highly affordable and overcomes the limitations of western setup of IMRI. Postoperative MRI images were highly acceptable and also highly affordable too.

Introduction Because of the inaccuracy of intermaxillary splints in orthognathic surgery, intraoperative guidance via a real time navigation system might represent a suitable method for enhancing the precision of maxillary positioning. Therefore, in this clinical trial, maxillary repositioning after Le Fort I osteotomy was guided splintless by an electromagnetic navigation system. Materials and methods Conservatively planned maxillary reposition in each of 5 patients was transferred to a novel software module of the electromagnetic navigation system. Intraoperatively, after Le Fort I osteotomy, the software guided the maxilla to the targeted position. Accuracy was evaluated by pre- and postoperative cone beam computer tomography imaging (the vectorial distance of the incisal marker points was measured in three dimensions) and compared with that of a splint transposed control group. Results The repositioning of the maxilla guided by the electromagnetic navigation system was intuitive and simple to accomplish. The achieved maxillary position with a deviation of 0.7 mm on average to the planned position was equally accurate compared with that of the splint transposed control group of 0.5 mm (p > 0.05). Discussion The data of this clinical study display good accuracy for splintless electromagnetic-navigated maxillary positioning. Nevertheless, this method does not surpass the splint-encoded gold standard with regard to accuracy. Future investigations will be necessary to show the full potential of electromagnetic navigation in orthognathic surgery.

Craniomaxillofacial reconstructive surgery is a challenging field. First it aims to restore primary functions and second to preserve craniofacial anatomical features like symmetry and harmony. Three-dimensional (3D) printed biomodels have been widely adopted in medical fields by providing tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. Craniomaxillofacial reconstructive surgery was one of the first areas to implement 3D printing technology in their practice. Biomodeling has been used in craniofacial reconstruction of traumatic injuries, congenital disorders, tumor removal, iatrogenic injuries (e.g., decompressive craniectomies), orthognathic surgery, and implantology. 3D printing has proven to improve and enable an optimization of preoperative planning, develop intraoperative guidance tools, reduce operative time, and significantly improve the biofunctional and the aesthetic outcome. This technology has also shown great potential in enriching the teaching of medical students and surgical residents. The aim of this review is to present the current status of 3D printing technology and its practical and innovative applications, specifically in craniomaxillofacial reconstructive surgery, illustrated with two clinical cases where the 3D printing technology was successfully used.

Fluorescence-guided resections have become standard of care for malignant gliomas. Strong fluorescence has been shown to correlate with solid enhancing tumor. However, with experience it has also been shown that visualized fluorescence may not identify the entire extent of the tumor. Knowing that malignant gliomas extend beyond the contrast-enhancing tumor seen on magnetic resonance imaging (MRI), reliance only on the fluorescence intraoperatively may not be enough. Intraoperative ultrasound is a readily available tool for real-time assessment of resection status, irrespective of the tumor type. We describe one such case in which after resecting all the visible fluorescing tumor component, we identified a significant component of nonfluorescing tumor, using intraoperative ultrasound that was further resected completely. This illustrates the need for multimodal intraoperative guidance for achieving optimal tumor resection in malignant gliomas.

Background Optical neuronavigation-guided intracranial surgery has become increasingly common in veterinary medicine, but its use has not yet been described in horses. Objectives To determine the feasibility of optical neuronavigation-guided intracranial biopsy procedures in the horse, compare the use of the standard fiducial array and anatomic landmarks for patient registration, and evaluate surgeon experience. Animals Six equine cadaver heads. Methods Computed tomography images of each specimen were acquired, with the fiducial array rigidly secured to the frontal bone. Six targets were selected in each specimen. Patient registration was performed separately for 3 targets using the fiducial array, and for 3 targets using anatomic landmarks. In lieu of biopsy, 1 mm diameter wire seeds were placed at each target. Postoperative images were coregistered with the planning scan to calculate Euclidian distance from the tip of the seed to the target. Results No statistical difference between registration techniques was identified. The impact of surgeon experience was examined for each technique using a Mann-Whitney U test. The experienced surgeon was significantly closer to the intended target (median = 2.52 mm) than were the novice surgeons (median = 6.55 mm) using the fiducial array (P = .001). Although not statistically significant (P = .31), for the experienced surgeon the median distance to target was similar when registering with the fiducial array (2.47 mm) and anatomic landmarks (2.58 mm). Conclusions and clinical importance Registration using both fiducial arrays and anatomic landmarks for brain biopsy using optical neuronavigation in horses is feasible.

With the continuous progress of virtual simulation technology, medical surgery visualization system has been developed from two-dimensional to three-dimensional, from digital to network and intelligentization. The visualization system with mixed reality technology will also be used in all stage of medical surgery, such as case discussion, surgical planning, intraoperative guidance, post-operative evaluation, rehabilitation, so as to further promote high intelligence, high precision of medical surgery, and consequently improve effectiveness of treatment and quality of medical service. This paper discusses the composition and technical characteristics of medical operation visualization system based on mixed reality technology, and introduces some typical applications of mixed reality technology in medical operation visualization, which provides a new perspective for the application of mixed technology in medical surgery.

Spinal instrumentation has evolved substantially in recent years. In keeping up with this ever-changing landscape, the spine surgeon must be cognizant of the potential complications associated with applying these techniques of spinal fixation. This chapter focuses on enumerating the potential complications associated with placing instrumentation in the subaxial cervical, thoracic, lumbar, and sacral spine in addition to the pelvis. Potential complications can range in severity from a small breach with no sequelae, to an organ or neurovascular injury with conceivably disastrous consequences. This chapter goes on to demonstrate that these complications are avoidable through a meticulous and thorough understanding of the relevant anatomy. Furthermore, this knowledge may be augmented intraoperatively through the use of X-rays, fluoroscopy, or stereotactic guidance. Additionally, these modalities also offer a method of intraoperative verification of hardware placement in order to confirm satisfactory position of instrumentation. Therefore, with a solid anatomical fund of knowledge and the proper intraoperative guidance/verification, the risk of instrumentation-related complications can be maximally mitigated.

Malignant glioma is characterized by active angiogenesis, high invasiveness and infiltration, and extremely rapid growth. Accurate visualization of glioma is crucial to the early diagnosis, preoperative localization, intraoperative guidance, and therapeutic evaluation and thus facilitates the clinical decision-making and improves the clinical outcomes of patients. However, conventional contrast agents directed toward intracranial glioma remain challenging, largely attributed to the existence of physiopathologic barriers unique to brain tumors. Remarkable advancements in nanotechnology and nanomedicine open a multidisciplinary field to design various nanoprobes for overcoming the physiopathologic barriers and for improved glioma imaging. This chapter starts with the critical biological challenges facing intracranial glioma. The innovative approaches for enhancing blood-brain barrier permeability and improved glioma targeting ability are presented. It then provides an overview of the unique advantages of nanomaterials for glioma imaging. The advanced applications of nanoprobes in intracranial glioma imaging are reviewed in detail, including magnetic resonance imaging, photoacoustic imaging, fluorescence imaging, multimodality imaging, and intraoperative glioma margin delineation. Finally, the current challenges and perspectives of this field are also discussed.

Recent technological advances have enabled real-time near-infrared fluorescence cholangiography (NIRFC) with indocyanine green (ICG). Whereas several studies have shown its feasibility, dosing and timing for practical use have not been optimized. We undertook a prospective study with systematic variation of dosing and timing from injection of ICG to visualization. Adult patients undergoing laparoscopic biliary and hepatic operations were enrolled. Intravenous ICG (0.02-0.25 mg/kg) was administered at times ranging from 10 to 180 minutes prior to planned visualization. The porta hepatis was examined using a dedicated laparoscopic system equipped to detect NIRFC. Quantitative analysis of intraoperative fluorescence was performed using a scoring system to identify biliary structures. A total of 37 patients were enrolled. Visualization of the extrahepatic biliary tract improved with increasing doses of ICG, with qualitative scores improving from 1.9 ± 1.2 (out of 5) with a 0.02-mg/kg dose to 3.4 ± 1.3 with a 0.25-mg/kg dose ( P < .05 for 0.02 vs 0.25 mg/kg). Visualization was also significantly better with increased time after ICG administration (1.1 ± 0.3 for 10 minutes vs 3.4 ± 1.1 for 45 minutes, P < .01). Similarly, quantitative measures also improved with both dose and time. There were no complications from the administration of ICG. These results suggest that a dose of 0.25 mg/kg administered at least 45 minutes prior to visualization facilitates intraoperative anatomical identification. The dosage and timing of administration of ICG prior to intraoperative visualization are within a range where it can be administered in a practical, safe, and effective manner to allow intraoperative identification of extrahepatic biliary anatomy using NIRFC.

Transoesophageal echocardiography (TOE) is used in the perioperative arena to monitor patients during life-threatening emergencies, cardiac and high-risk non-cardiac surgeries. It provides qualitative and quantitative information on valvular and ventricular functions, and dynamic cardiac anatomy can be displayed with a physiological perspective. This technology has evolved from two-dimensional (2D) to the ready availability of real-time three-dimensional (RT-3D) imaging in the operating rooms. Enhanced spatial and temporal resolutions with 3D imaging have most significantly impacted the quality of intraoperative surgical valve repair and replacement decisions. Additionally, 3D imaging has facilitated the advent of minimally invasive and percutaneous interventions for structural heart disease. Information derived from TEE is routinely used to evaluate a patient's suitability for an intervention, provide guidance during the intervention and eventually comment on the quality and success of the procedure. Expertise in perioperative TEE is an integral component of a cardiac anaesthesiologist's skill sets. With structural heart disease interventions becoming more minimally invasive, the intraoperative guidance provided by TEE will continue to be a critical component of these procedures. With improving computational and processing power, the expectations from TEE will continue to be incremental in the perioperative arena.

Purpose The aim of this study was to compare the visual outcome of participants undergoing toric intraocular lens (IOL) implantation after cataract extraction using manual marking versus digital marking for intraoperative guidance. Methods Randomized controlled trial of participants with cataract and corneal astigmatism of 1.00 D-4.50 D. The eyes were grouped into manual marking (Group 1) and digital marking (Group 2). Preoperative Uncorrected distance visual acuity (UDVA), Corrected distance visual acuity (CDVA), and corneal astigmatism were determined. IOL power and axis of alignment were determined using Barrett toric calculator. Eyes were marked by bubble marker and Mendez ring in group 1 and by VERION (Alcon, Fort Worth, Texas) digital overlay in Group 2. Postoperatively, UDVA, CDVA, residual refractive cylinder and IOL misalignment were determined (iTrace system, Tracey technologies) at 1 week, 6 weeks, and 3 months. Results A total of 61 eyes of 50 participants, 31 in Group 1 and 30 in Group 2, were studied. The mean postoperative cylindrical error was 0.50 ± 0.39 D in Group 1 and 0.29 ± 0.34 D in Group 2 (P = 0.03). 67.74% (n = 21) and 93.55% (n = 29) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 1, whereas 83.33% (n = 25) and 100% (n = 30) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 2 at 3 months postoperatively. Toric IOL misalignment was 4.71 ± 3.12° in Group 1 and 4.03 ± 2.99° in Group 2 (P = 0.39). Conclusion Accurate manual marking and digital marking are equally effective guides for toric IOL alignment, intraoperatively.

Complex congenital aortic anomalies include diverse types of malformations that may be clinically asymptomatic or present with respiratory or esophageal symptoms. These anomalies may be associated with other congenital heart diseases. It is hard to identify the accurate anatomic vessel location from two-dimensional imaging data, such as computed tomography. As an additive manufacturing method, three-dimensional (3-D) printing can covert the acquired imaging data into 3-D physical models. This protocol describes the procedure for modeling the volumetric DICOM imaging into 3-D data and printing it as an anatomically realistic 3-D model. Using this model, surgeons can identify the vessel location of complex aortic anomalies, which is helpful for pre-operative planning and intra-operative guidance.