Deformable registration of preoperative MR and intraoperative long-length tomosynthesis images for guidance of spine surgery via image synthesis

PURPOSE

Improved integration and use of preoperative imaging during surgery hold significant potential for enhancing treatment planning and instrument guidance through surgical navigation. Despite its prevalent use in diagnostic settings, MR imaging is rarely used for navigation in spine surgery. This study aims to leverage MR imaging for intraoperative visualization of spine anatomy, particularly in cases where CT imaging is unavailable or when minimizing radiation exposure is essential, such as in pediatric surgery.

METHODS

This work presents a method for deformable 3D-2D registration of preoperative MR images with a novel intraoperative long-length tomosynthesis imaging modality (viz., Long-Film [LF]). A conditional generative adversarial network is used to translate MR images to an intermediate bone image suitable for registration, followed by a model-based 3D-2D registration algorithm to deformably map the synthesized images to LF images. The algorithm's performance was evaluated on cadaveric specimens with implanted markers and controlled deformation, and in clinical images of patients undergoing spine surgery as part of a large-scale clinical study on LF imaging.

RESULTS

The proposed method yielded a median 2D projection distance error of 2.0 mm (interquartile range [IQR]: 1.1-3.3 mm) and a 3D target registration error of 1.5 mm (IQR: 0.8-2.1 mm) in cadaver studies. Notably, the multi-scale approach exhibited significantly higher accuracy compared to rigid solutions and effectively managed the challenges posed by piecewise rigid spine deformation. The robustness and consistency of the method were evaluated on clinical images, yielding no outliers on vertebrae without surgical instrumentation and 3% outliers on vertebrae with instrumentation.

CONCLUSIONS

This work constitutes the first reported approach for deformable MR to LF registration based on deep image synthesis. The proposed framework provides access to the preoperative annotations and planning information during surgery and enables surgical navigation within the context of MR images and/or dual-plane LF images.

Robotic assisted versus laparoscopic surgery for deep endometriosis: a meta-analysis of current evidence

Endometriosis is a benign inflammatory onco-mimetic disease affecting 10-15% of women in the world. When it is refractory to medical treatments, surgery may be required. Usually, laparoscopy is the preferred approach, but robotic surgery has gained popularity in the last 15 years. This study aims to evaluate the safety and efficacy of robotic-assisted laparoscopic surgery (RAS) versus conventional laparoscopic surgery (LPS) in the treatment of endometriosis. This study adheres to PRISMA guidelines and is registered with PROSPERO. Studies reporting perioperative data comparing RAS and LPS surgery in patients with endometriosis querying PubMed, Google Scholar and ClinicalTrials.gov were included in the analysis. The Quality Assessment of Diagnostic Accuracy Studies 2 tool (QUADAS-2) was used for the quality assessment of the selected articles. Fourteen studies were identified, including 2709 patients with endometriosis stage I-IV for the meta-analysis. There were no significant differences between RAS and LPS in terms of intraoperative and postoperative complications, conversion rate and estimated blood loss. However, patients in the RAS group have a longer operative time (p < 0.0001) and longer hospital stay (p = 0.020) than those in the laparoscopic group. Robotic surgery is not inferior to laparoscopy in patients with endometriosis in terms of surgical outcomes; however, RAS requires longer operative times and longer hospital stay. The benefits of robotic surgery should be sought in the easiest potential integration of robotic platforms with new technologies. Prospective studies comparing laparoscopy to the new robotic systems are desirable for greater robustness of scientific evidence.

Non-rigid scene reconstruction of deformable soft tissue with monocular endoscopy in minimally invasive surgery

PURPOSE

The utilization of image-guided surgery has demonstrated its ability to improve the precision and safety of minimally invasive surgery (MIS). Non-rigid scene reconstruction is a challenge in image-guided system duo to uniform texture, smoke, and instrument occlusion, etc. METHODS: In this paper, we introduced an algorithm for 3D reconstruction aimed at non-rigid surgery scenes. The proposed method comprises two main components: firstly, the front-end process involves the initial reconstruction of 3D information for deformable soft tissues using embedded deformation graph (EDG) on the basis of dual quaternions, enabling the reconstruction without the need for prior knowledge of the target. Secondly, the EDG is integrated with isometric nonrigid structure from motion (Iso-NRSFM) to facilitate centralized optimization of the observed map points and camera motion across different time instances in deformable scenes.

RESULTS

For the quantitative evaluation of the proposed method, we conducted comparative experiments with both synthetic datasets and publicly available datasets against the state-of-the-art 3D reconstruction method, DefSLAM. The test results show that our proposed method achieved a maximum reduction of 1.6 mm in average reconstruction error compared to method DefSLAM across all datasets. Additionally, qualitative experiments were performed on video scene datasets involving surgical instrument occlusions.

CONCLUSION

Our method proved to outperform DefSLAM on both synthetic datasets and public datasets through experiments, demonstrating its robustness and accuracy in the reconstruction of soft tissues in dynamic surgical scenes. This success highlights the potential clinical application of our method in delivering surgeons with critical shape and depth information for MIS.

Ultrasound-guided robotic surgical procedures: a systematic review

INTRODUCTION

Ultrasound has been nicknamed "the surgeon's stethoscope". The advantages of laparoscopic ultrasound beyond a substitute for the sense of touch are considerable, especially for robotic surgery. Being able to see through parenchyma and into vascular structures enables to avoid unnecessary dissection by providing a thorough assessment at every stage without the need for contrast media or ionising radiation. The limitations of restricted angulation and access within the abdominal cavity during laparoscopy can be overcome by robotic handling of miniaturised ultrasound probes and the use of various and specific frequencies will meet tissue- and organ-specific characteristics. The aim of this systematic review was to assess the reported applications of intraoperative ultrasound-guided robotic surgery and to outline future perspectives.

METHODS

The study adhered to the PRISMA guidelines. PubMed, Google Scholar, ScienceDirect and ClinicalTrials.gov were searched up to October 2023. Manuscripts reporting data on ultrasound-guided robotic procedures were included in the qualitative analysis.

RESULTS

20 studies met the inclusion criteria. The majority (53%) were related to the field of general surgery during liver, pancreas, spleen, gallbladder/bile duct, vascular and rectal surgery. This was followed by other fields of oncological surgery (42%) including urology, lung surgery, and retroperitoneal lymphadenectomy for metastases. Among the studies, ten (53%) focused on locating tumoral lesions and defining resection margins, four (15%) were designed to test the feasibility of robotic ultrasound-guided surgery, while two (10.5%) aimed to compare robotic and laparoscopic ultrasound probes. Additionally two studies (10.5%) evaluated the robotic drop-in probe one (5%) assessed the hepatic tissue consistency and another one (5%) aimed to visualize the blood flow in the splenic artery.

CONCLUSION

The advantages of robotic instrumentation, including ergonomics, dexterity, and precision of movements, are of relevance for robotic intraoperative ultrasound (RIOUS). The present systematic review demonstrates the virtue of RIOUS to support surgeons and potentially reduce minimally invasive procedure times.

Entirely robotic cochlear implant surgery

INTRODUCTION

Robot-assisted cochlear implant surgery (RACIS) as defined by the HEARO®-procedure performs minimal invasive cochlear implant (CI) surgery by directly drilling a keyhole trajectory towards the inner ear. Hitherto, an entirely robotic automation including electrode insertion has not been described yet. The feasability of using a newly developed, dedicated motorised device for automated electrode insertion in the first clinical case of entirely robotic cochlear implant surgery was investigated.

AIM

The aim is to report the first experience of entirely robotic cochlear implantation surgery.

INTERVENTION

RACIS with a straight flexible lateral wall electrode.

PRIMARY OUTCOME MEASUREMENTS

Electrode cochlear insertion depth.

SECONDARY OUTCOME MEASUREMENTS

The audiological outcome in terms of mean hearing thresholds.

CONCLUSION

Here, we report on a cochlear implant robot that performs the most complex surgical steps to place a cochlear implant array successfully in the inner ear and render similar audiological results as in conventional surgery. Robots can execute tasks beyond human dexterity and will probably pave the way to standardize residual hearing preservation and broadening the indication for electric-acoustic stimulation in the same ear with hybrid implants.

Take a shot! Natural language control of intelligent robotic X-ray systems in surgery

PURPOSE

The expanding capabilities of surgical systems bring with them increasing complexity in the interfaces that humans use to control them. Robotic C-arm X-ray imaging systems, for instance, often require manipulation of independent axes via joysticks, while higher-level control options hide inside device-specific menus. The complexity of these interfaces hinder "ready-to-hand" use of high-level functions. Natural language offers a flexible, familiar interface for surgeons to express their desired outcome rather than remembering the steps necessary to achieve it, enabling direct access to task-aware, patient-specific C-arm functionality.

METHODS

We present an English language voice interface for controlling a robotic X-ray imaging system with task-aware functions for pelvic trauma surgery. Our fully integrated system uses a large language model (LLM) to convert natural spoken commands into machine-readable instructions, enabling low-level commands like "Tilt back a bit," to increase the angular tilt or patient-specific directions like, "Go to the obturator oblique view of the right ramus," based on automated image analysis.

RESULTS

We evaluate our system with 212 prompts provided by an attending physician, in which the system performed satisfactory actions 97% of the time. To test the fully integrated system, we conduct a real-time study in which an attending physician placed orthopedic hardware along desired trajectories through an anthropomorphic phantom, interacting solely with an X-ray system via voice.

CONCLUSION

Voice interfaces offer a convenient, flexible way for surgeons to manipulate C-arms based on desired outcomes rather than device-specific processes. As LLMs grow increasingly capable, so too will their applications in supporting higher-level interactions with surgical assistance systems.

Correspondence attention for facial appearance simulation

In orthognathic surgical planning for patients with jaw deformities, it is crucial to accurately simulate the changes in facial appearance that follow the bony movement. Compared with the traditional biomechanics-based methods like the finite-element method (FEM), which are both labor-intensive and computationally inefficient, deep learning-based methods offer an efficient and robust modeling alternative. However, current methods do not account for the physical relationship between facial soft tissue and bony structure, causing them to fall short in accuracy compared to FEM. In this work, we propose an Attentive Correspondence assisted Movement Transformation network (ACMT-Net) to predict facial changes by correlating facial soft tissue changes with bony movement through a point-to-point attentive correspondence matrix. To ensure efficient training, we also introduce a contrastive loss for self-supervised pre-training of the ACMT-Net with a k-Nearest Neighbors (k-NN) based clustering. Experimental results on patients with jaw deformities show that our proposed solution can achieve significantly improved computational efficiency over the state-of-the-art FEM-based method with comparable facial change prediction accuracy.

Accuracy of implant placement with computer-aided static, dynamic, and robot-assisted surgery: a systematic review and meta-analysis of clinical trials

This systematic review explores the accuracy of computerized guided implant placement including computer-aided static, dynamic, and robot-assisted surgery. An electronic search up to February 28, 2023, was conducted using the PubMed, Embase, and Scopus databases using the search terms "surgery", "computer-assisted", "dynamic computer-assisted", "robotic surgical procedures", and "dental implants". The outcome variables were discrepancies including the implant's 3D-coronal, -apical and -angular deviations. Articles were selectively retrieved according to the inclusion and exclusion criteria, and the data were quantitatively meta-analysed to verify the study outcomes. Sixty-seven articles were finally identified and included for analysis. The accuracy comparison revealed an overall mean deviation at the entry point of 1.11 mm (95% CI: 1.02-1.19), and 1.40 mm (95% CI: 1.31-1.49) at the apex, and the angulation was 3.51˚ (95% CI: 3.27-3.75). Amongst computerized guided implant placements, the robotic system tended to show the lowest deviation (0.81 mm in coronal deviation, 0.77 mm in apical deviation, and 1.71˚ in angular deviation). No significant differences were found between the arch type and flap operation in cases of dynamic navigation. The fully-guided protocol demonstrated a significantly higher level of accuracy compared to the pilot-guided protocol, but did not show any significant difference when compared to the partially guided protocol. The use of computerized technology clinically affirms that operators can accurately place implants in three directions. Several studies agree that a fully guided protocol is the gold standard in clinical practice.

Current Application of Navigation Systems in Robotic-Assisted and Laparoscopic Partial Nephrectomy: Focus on the Improvement of Surgical Performance and Outcomes

Kidney cancer represents the third most prevalent malignancy among all types of genitourinary cancer worldwide. Currently, there is a growing trend of employing partial nephrectomy for the management of large and complex tumors. Surgical outcomes are associated with some amendable surgical factors, including warm ischemic time, pedicle clamping, preserved volume of renal parenchyma, appropriate surgical strategy, and precise resection of the tumor. Improving surgical performance is pivotal for achieving favorable surgical outcomes. Due to advancements in imaging visualization technology and the shift of the medical paradigm toward precision medicine, an increasing number of navigation systems have been implemented in partial nephrectomy procedures. The navigation system can assist surgeons in formulating optimal surgical strategies and enhance the safety, precision, and feasibility of resecting complex renal tumors. In this review, we provide an overview of currently available navigation systems and their feasible applications, with a focus on how they contribute to the improvement of surgical performance and outcomes during robotic-assisted and laparoscopic partial nephrectomy.

Translocator Protein 18 kDa (TSPO): A Promising Molecular Target for Image-Guided Surgery of Solid Cancers

The translocator protein 18-kDa (TSPO) is a mitochondrial membrane protein that is previously identified as the peripheral benzodiazepine receptor (PBR). Furthermore, it plays a significant role in a diverse range of biochemical processes, including steroidogenesis, mitochondrial cholesterol transport, cell survival and death, cell proliferation, and carcinogenesis. Several investigations also reported its roles in various types of cancers, including colorectal, brain, breast, prostate, and lung cancers, as well as melanoma. According to a previous study, the expression of TSPO was upregulated in cancer cells, which corresponds to an aggressive phenotype and/or poor prognosis. Consequently, the potential for crafting diagnostic and prognostic tools with a focus on TSPO holds great potential. In this context, several radioligands designed to target this protein have been identified, and some of the candidates have advanced to clinical trials. In recent years, the use of hybrid probes with radioactive and fluorescence molecules for image-guided surgery has exhibited promising results in animal and human studies. This indicates that the approach can serve as a valuable surgical navigator during cancer surgery. The current hybrid probes are built from various molecular platforms, including small molecules, nanoparticles, and antibodies. Although several TSPO-targeted imaging probes have been developed, their development for image-guided surgery of cancers is still limited. Therefore, this review aims to highlight recent findings on the involvement of TSPO in carcinogenesis, as well as provide a new perspective on the potential application of TSPO-targeted hybrid probes for image-guided surgery.

First-in-human validation of a DROP-IN β-probe for robotic radioguided surgery: defining optimal signal-to-background discrimination algorithm

PURPOSE

In radioguided surgery (RGS), radiopharmaceuticals are used to generate preoperative roadmaps (e.g., PET/CT) and to facilitate intraoperative tracing of tracer avid lesions. Within RGS, there is a push toward the use of receptor-targeted radiopharmaceuticals, a trend that also has to align with the surgical move toward minimal invasive robotic surgery. Building on our initial ex vivo evaluation, this study investigates the clinical translation of a DROP-IN β probe in robotic PSMA-guided prostate cancer surgery.

METHODS

A clinical-grade DROP-IN β probe was developed to support the detection of PET radioisotopes (e.g., 68 Ga). The prototype was evaluated in 7 primary prostate cancer patients, having at least 1 lymph node metastases visible on PSMA-PET. Patients were scheduled for radical prostatectomy combined with extended pelvic lymph node dissection. At the beginning of surgery, patients were injected with 1.1 MBq/kg of [68Ga]Ga-PSMA. The β probe was used to trace PSMA-expressing lymph nodes in vivo. To support intraoperative decision-making, a statistical software algorithm was defined and optimized on this dataset to help the surgeon discriminate between probe signals coming from tumors and healthy tissue.

RESULTS

The DROP-IN β probe helped provide the surgeon with autonomous and highly maneuverable tracer detection. A total of 66 samples (i.e., lymph node specimens) were analyzed in vivo, of which 31 (47%) were found to be malignant. After optimization of the signal cutoff algorithm, we found a probe detection rate of 78% of the PSMA-PET-positive samples, a sensitivity of 76%, and a specificity of 93%, as compared to pathologic evaluation.

CONCLUSION

This study shows the first-in-human use of a DROP-IN β probe, supporting the integration of β radio guidance and robotic surgery. The achieved competitive sensitivity and specificity help open the world of robotic RGS to a whole new range of radiopharmaceuticals.

Tracked ultrasound registration for intraoperative navigation during pediatric bone tumor resections with soft tissue components: a porcine cadaver study

PURPOSE

Resection of pediatric osteosarcoma in the extremities with soft tissue involvement presents surgical challenges due to difficult visualization and palpation of the tumor. Therefore, an adequate image-guided surgery (IGS) system is required for more accurate tumor resection. The use of a 3D model in combination with intraoperative tracked ultrasound (iUS) may enhance surgical decision making. This study evaluates the clinical feasibility of iUS as a surgical tool using a porcine cadaver model.

METHODS

First, a 3D model of the porcine lower limb was created based on preoperative scans. Second, the bone surface of the tibia was automatically detected with an iUS by a sweep on the skin. The bone surface of the preoperative 3D model was then matched with the bone surface detected by the iUS. Ten artificial targets were used to calculate the target registration error (TRE). Intraoperative performance of iUS IGS was evaluated by six pediatric surgeons and two pediatric oncologic orthopedists. Finally, user experience was assessed with a post-procedural questionnaire.

RESULTS

Eight registration procedures were performed with a mean TRE of 6.78 ± 1.33 mm. The surgeons agreed about the willingness for clinical implementation in their current clinical practice. They mentioned the additional clinical value of iUS in combination with the 3D model for the localization of the soft tissue components of the tumor. The concept of the proposed IGS system is considered feasible by the clinical panel, but the large TRE and degree of automation need to be addressed in further work.

CONCLUSION

The participating pediatric surgeons and orthopedists were convinced of the clinical value of the interaction between the iUS and the 3D model. Further research is required to improve the surgical accuracy and degree of automation of iUS-based registration systems for the surgical management of pediatric osteosarcoma.

First-in-human Evaluation of a Prostate-specific Membrane Antigen-targeted Near-infrared Fluorescent Small Molecule for Fluorescence-based Identification of Prostate Cancer in Patients with High-risk Prostate Cancer Undergoing Robotic-assisted Prostatectomy

BACKGROUND

Men with high-risk prostate cancer undergoing surgery likely recur due to failure to completely excise regional and/or local disease.

OBJECTIVE

The first-in-human evaluation of safety, pharmacokinetics, and exploratory efficacy of IS-002, a novel near-infrared prostate-specific membrane antigen (PSMA)-targeted fluorescence imaging agent, designed for intraoperative prostate cancer visualization.

DESIGN, SETTING, AND PARTICIPANTS

A phase 1, single-center, dose-escalation study was conducted in 24 men with high-risk prostate cancer scheduled for robotic-assisted radical prostatectomy with (extended) pelvic lymph node dissection using the da Vinci surgical system.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Adverse events (AEs), vital signs, complete blood count, complete metabolic panel, urinalysis, and electrocardiogram were assessed over a 14-d period and compared with baseline. The pharmacokinetic profile of IS-002 was determined. Diagnostic accuracy was assessed for exploratory efficacy.

RESULTS AND LIMITATIONS

AEs predominantly included discoloration of urine (n = 22/24; expected, related, grade 1). There were no grade ≥2 AEs. IS-002 Cmax and area under the curve increased with increasing dose. Plasma concentrations declined rapidly in a biphasic manner, with the median terminal half-lives ranging from 5.0 to 7.6 h, independent of dose and renal function. At 25 μg/kg, the exploratory efficacy readouts for the negative and positive predictive values were, 97% and 45% for lymph nodes, and 100% and 80% for residual/locoregional disease detection, respectively.

CONCLUSIONS

IS-002 is safe and well tolerated, and has the potential to enable intraoperative tumor detection that could not be identified using standard imaging.

PATIENT SUMMARY

IS-002 is a new imaging agent that specifically targets the prostate-specific membrane antigen receptor. In this study, we tested IS-002 for the first time in men with high-risk prostate cancer undergoing surgery and found that IS-002 is safe, is cleared from the body quickly, and potentially allows identification of prostate cancer in areas that would not be identified by conventional white light imaging.

A robotic system for transthoracic puncture of pulmonary nodules based on gated respiratory compensation

BACKGROUND AND OBJECTIVE

With the urgent demands for rapid and precise localization of pulmonary nodules in procedures such as transthoracic puncture biopsy and thoracoscopic surgery, many surgical navigation and robotic systems are applied in the clinical practice of thoracic operation. However, current available positioning methods have certain limitations, including high radiation exposure, large errors from respiratory, complicated and time-consuming procedures, etc. METHODS: To address these issues, a preoperative computed tomography (CT) image-guided robotic system for transthoracic puncture was proposed in this study. Firstly, an algorithm for puncture path planning based on constraints from clinical knowledge was developed. This algorithm enables the calculation of Pareto optimal solutions for multiple clinical targets concerning puncture angle, puncture length, and distance from hazardous areas. Secondly, to eradicate intraoperative radiation exposure, a fast registration method based on preoperative CT and gated respiration compensation was proposed. The registration process could be completed by the direct selection of points on the skin near the sternum using a hand-held probe. Gating detection and joint optimization algorithms are then performed on the collected point cloud data to compensate for errors from respiratory motion. Thirdly, to enhance accuracy and intraoperative safety, the puncture guide was utilized as an end effector to restrict the movement of the optically tracked needle, then risky actions with patient contact would be strictly limited.

RESULTS

The proposed system was evaluated through phantom experiments on our custom-designed simulation test platform for patient respiratory motion to assess its accuracy and feasibility. The results demonstrated an average target point error (TPE) of 2.46 ± 0.68 mm and an angle error (AE) of 1.49 ± 0.45° for the robotic system.

CONCLUSIONS

In conclusion, our proposed system ensures accuracy, surgical efficiency, and safety while also reducing needle insertions and radiation exposure in transthoracic puncture procedures, thus offering substantial potential for clinical application.

Current clinical applications of Cerenkov luminescence for intraoperative molecular imaging

BACKGROUND

Cerenkov luminescence imaging (CLI) is a new emerging technology that can be used for optical imaging of approved radiotracers, both in a preclinical, and even more recently, in a clinical context with rapid imaging times, low costs, and detection in real-time (Grootendorst et al. Clin Transl Imaging 4(5):353-66, 2016); Wang et al. Photonics 9(6):390, 2022). This brief review provides an overview of clinical applications of CLI with a focus on intraoperative margin assessment (IMA) to address shortcomings and provide insight for future work in this application.

METHODS

A literature review was performed using PubMed using the search words Cerenkov luminescence imaging (CLI), intraoperative margin assessment (IMA), and image-guided surgery. Articles were selected based on title, abstract, content, and application.

RESULTS

Original research was summarized to examine advantages and limitations of CLI compared to other modalities for IMA. The characteristics of Cerenkov luminescence (CL) are defined, and results from relevant clinical trials are discussed. Prospects of ongoing clinical trials are reviewed, along with technological advancements related to CLI.

CONCLUSION

CLI is a proven method for molecular imaging and shows feasibility for determining intraoperative margins if future work involves establishing quantitative approaches for attenuation and scattering, depth analysis, and radiation safety for CLI at a larger scale.

Molecular image-guided surgery in gynaecological cancer: where do we stand?

PURPOSE

The aim of this review is to give an overview of the current status of molecular image-guided surgery in gynaecological malignancies, from both clinical and technological points of view.

METHODS

A narrative approach was taken to describe the relevant literature, focusing on clinical applications of molecular image-guided surgery in gynaecology, preoperative imaging as surgical roadmap, and intraoperative devices.

RESULTS

The most common clinical application in gynaecology is sentinel node biopsy (SNB). Other promising approaches are receptor-target modalities and occult lesion localisation. Preoperative SPECT/CT and PET/CT permit a roadmap for adequate surgical planning. Intraoperative detection modalities span from 1D probes to 2D portable cameras and 3D freehand imaging.

CONCLUSION

After successful application of radio-guided SNB and SPECT, innovation is leaning towards hybrid modalities, such as hybrid tracer and fusion of imaging approaches including SPECT/CT and PET/CT. Robotic surgery, as well as augmented reality and virtual reality techniques, is leading to application of these innovative technologies to the clinical setting, guiding surgeons towards a precise, personalised, and minimally invasive approach.

New EAU/ASCO guideline recommendations on sentinel node biopsy for penile cancer and remaining challenges from a nuclear medicine perspective

INTRODUCTION

The European Association of Urology (EAU) and the American Society of Clinical Oncology (ASCO) recently issued updated guidelines on penile cancer, emphasising dynamic sentinel node biopsy (DSNB) as the preferred method for surgical staging among patients with invasive penile tumours and no palpable inguinal lymphadenopathy. This paper outlines the rationale behind this new recommendation and describes remaining challenges, as well as strategies for promoting DSNB worldwide.

MAIN TEXT

DSNB offers high diagnostic accuracy with the lowest postoperative complications compared to open or minimally invasive inguinal lymph node dissection (ILND), prompting its preference in the new guidelines. Nevertheless, despite its advantages, there are challenges hampering the widespread adoption of DSNB. This includes the false-negative rate associated with DSNB and the potential negative impact on patient outcome. To address this issue, improvements should be made in several areas, including refining the timing and interpretation of the lymphoscintigraphy and the single photon emission computed tomography/computed tomography images. In addition, the quantity of tracer employed and choice of the injection site for the radiopharmaceutical should be optimised. Finally, limiting the removal of nodes without tracer activity during surgery may help minimise complication rates.

CONCLUSION

Over the years, DSNB has evolved significantly, related to the dedicated efforts and innovations in nuclear medicine and subsequent clinical studies validating its efficacy. It is now strongly recommended for surgical staging among selected penile cancer patients. To optimise DSNB further, multidisciplinary collaborative research is required to improve SN identification for better diagnostic accuracy and fewer complications.

ST-ITEF: Spatio-Temporal Intraoperative Task Estimating Framework to recognize surgical phase and predict instrument path based on multi-object tracking in keratoplasty

Computer-assisted cognition guidance for surgical robotics by computer vision is a potential future outcome, which could facilitate the surgery for both operation accuracy and autonomy level. In this paper, multiple-object segmentation and feature extraction from this segmentation are combined to determine and predict surgical manipulation. A novel three-stage Spatio-Temporal Intraoperative Task Estimating Framework is proposed, with a quantitative expression derived from ophthalmologists' visual information process and also with the multi-object tracking of surgical instruments and human corneas involved in keratoplasty. In the estimation of intraoperative workflow, quantifying the operation parameters is still an open challenge. This problem is tackled by extracting key geometric properties from multi-object segmentation and calculating the relative position among instruments and corneas. A decision framework is further proposed, based on prior geometric properties, to recognize the current surgical phase and predict the instrument path for each phase. Our framework is tested and evaluated by real human keratoplasty videos. The optimized DeepLabV3 with image filtration won the competitive class-IoU in the segmentation task and the mean phase jaccard reached 55.58 % for the phase recognition. Both the qualitative and quantitative results indicate that our framework can achieve accurate segmentation and surgical phase recognition under complex disturbance. The Intraoperative Task Estimating Framework would be highly potential to guide surgical robots in clinical practice.

A cGAN-based network for depth estimation from bronchoscopic images

PURPOSE

Depth estimation is the basis of 3D reconstruction of airway structure from 2D bronchoscopic scenes, which can be further used to develop a vision-based bronchoscopic navigation system. This work aims to improve the performance of depth estimation directly from bronchoscopic images by training a depth estimation network on both synthetic and real datasets.

METHODS

We propose a cGAN-based network Bronchoscopic-Depth-GAN (BronchoDep-GAN) to estimate depth from bronchoscopic images by translating bronchoscopic images into depth maps. The network is trained in a supervised way learning from synthetic textured bronchoscopic image-depth pairs and virtual bronchoscopic image-depth pairs, and simultaneously, also in an unsupervised way learning from unpaired real bronchoscopic images and depth maps to adapt the model to real bronchoscopic scenes.

RESULTS

Our method is tested on both synthetic data and real data. However, the tests on real data are only qualitative, as no ground truth is available. The results show that our network obtains better accuracy in all cases in estimating depth from bronchoscopic images compared to the well-known cGANs pix2pix.

CONCLUSIONS

Including virtual and real bronchoscopic images in the training phase of the depth estimation networks can improve depth estimation's performance on both synthetic and real scenes. Further validation of this work is planned on 3D clinical phantoms. Based on the depth estimation results obtained in this work, the accuracy of locating bronchoscopes with corresponding pre-operative CTs will also be evaluated in comparison with the current clinical status.

Surgical navigation in maxillofacial surgery: A French national survey

PURPOSE

to gain a national understanding of the utilization of surgical navigation among maxillofacial surgeons in France through a web-based questionnaire.

METHODS

A 14-point multiple-choice questionnaire was created and distributed to the participants, divided into two sections. The first section gathered general information about the respondents, and the second section provided an overview of the use of surgical navigation.

RESULT

A total of 75 participants completed the survey. The results showed that a majority of university hospital departments (65%) utilize an intra-operative 3D imaging system, while very few private clinics and general hospitals use this technology.

CONCLUSION

The survey suggests that surgical navigation is primarily used in university centers in French maxillofacial surgery, with limited utilization and non-standardized indications for use.

The value of Augmented Reality in surgery - A usability study on laparoscopic liver surgery

Augmented Reality (AR) is considered to be a promising technology for the guidance of laparoscopic liver surgery. By overlaying pre-operative 3D information of the liver and internal blood vessels on the laparoscopic view, surgeons can better understand the location of critical structures. In an effort to enable AR, several authors have focused on the development of methods to obtain an accurate alignment between the laparoscopic video image and the pre-operative 3D data of the liver, without assessing the benefit that the resulting overlay can provide during surgery. In this paper, we present a study that aims to assess quantitatively and qualitatively the value of an AR overlay in laparoscopic surgery during a simulated surgical task on a phantom setup. We design a study where participants are asked to physically localise pre-operative tumours in a liver phantom using three image guidance conditions - a baseline condition without any image guidance, a condition where the 3D surfaces of the liver are aligned to the video and displayed on a black background, and a condition where video see-through AR is displayed on the laparoscopic video. Using data collected from a cohort of 24 participants which include 12 surgeons, we observe that compared to the baseline, AR decreases the median localisation error of surgeons on non-peripheral targets from 25.8 mm to 9.2 mm. Using subjective feedback, we also identify that AR introduces usability improvements in the surgical task and increases the perceived confidence of the users. Between the two tested displays, the majority of participants preferred to use the AR overlay instead of navigated view of the 3D surfaces on a separate screen. We conclude that AR has the potential to improve performance and decision making in laparoscopic surgery, and that improvements in overlay alignment accuracy and depth perception should be pursued in the future.

Setting-up a training programme for intraoperative molecular imaging and sentinel node mapping: how to teach? How to learn?

BACKGROUND

The current expansion of image-guided surgery is closely related to the role played by radio-guided surgery in supporting the sentinel node (SN) procedure during more than three decades. The so-called triple approach (lymphoscintigraphy, gamma probe detection and blue dye) was not only essential in the seminal validation of the SN procedure but also a first collective learning effort based on skill transfer and outcome-related evaluation which laid the fundaments to delineate the field of intraoperative molecular imaging (IMI) based on a similar multimodality approach and multidisciplinary practice.

METHODS

These elements are also becoming valid in the current incorporation of SPECT/CT and PET/CT to existing and new protocols of IMI procedures and SN mapping concerning other clinical applications. On the other hand, there is a growing tendency to combine novel modern technologies in an allied role with gamma guidance in the operating room following the development of hybrid tracers and multimodal detection approaches. Against this background, learning initiatives are required for professionals working in this area.

RESULTS

This objective has led to a group of European practitioners with large experience in SN mapping and IMI applications to give shape to a programme made up out of specific learning modules aimed to be used as a conductive thread in peripherical or centralised training instances concerning the topic.

CONCLUSION

The presented work, written as a tutorial review, is placed in an available prior-art context and is primarily aimed at medical and paramedical practitioners as well as at hardware and software developers.

A new bimodal approach for sentinel lymph node imaging in prostate cancer using a magnetic and fluorescent hybrid tracer

PURPOSE

To obtain initial data on sentinel lymph node (SLN) visualisation by pre-operative magnetic resonance imaging (MRI) and intra-operative bimodal SLN identification using a new magnetic fluorescent hybrid tracer in prostate cancer (PCa) patients.

METHODS

Ten patients at > 5% risk for lymph node (LN) invasion were included. The day before surgery, a magnetic fluorescent hybrid tracer consisting of superparamagnetic iron oxide nanoparticles (SPION) and indocyanine green was transrectally injected into the prostate. Five hours after injection, transversal pelvic MRI scans were recorded and T2*-weighed images were screened for pelvic LNs with SPION uptake. Intra-operatively, magnetically active and/or fluorescent SLNs were detected by a handheld magnetometer and near-infrared fluorescence imaging (FI). Extended pelvic lymph node dissection (PLND) and radical prostatectomy completed the surgery. All resected specimens were checked ex situ for magnetic activity and fluorescence and were histopathologically examined.

RESULTS

Pre-operative MRI identified 145 pelvic LNs with SPION uptake. In total, 75 (median 6, range 3‒13) magnetically active SLNs were resected, including 14 SLNs not seen on MRI. FI identified 89 fluorescent LNs (median 8.5, range 4‒13) of which 15 LNs were not magnetically active. Concordance of the different techniques was 70% for pre-operative MRI vs. magnetometer-guided PLND and 88% for magnetic vs. fluorescent SLN detection.

CONCLUSION

These are the first promising results of bimodal, magnetic fluorescent SLN detection in PCa patients. Our magnetic fluorescent hybrid approach provides the surgeon a pre-operative lymphatic roadmap by using MRI and intra-operative visual guidance through the application of a fluorescent lymphatic agent. The diagnostic accuracy of our new hybrid approach has to be evaluated in further studies.

TRIAL REGISTRATION

DRKS00032808. Registered 04 October 2023, retrospectively registered.

How to objectively evaluate the impact of image-guided surgery technologies

PURPOSE

This manuscript aims to provide a better understanding of methods and techniques with which one can better quantify the impact of image-guided surgical technologies.

METHODS

A literature review was conducted with regard to economic and technical methods of medical device evaluation in various countries. Attention was focused on applications related to image-guided interventions that have enabled procedures to be performed in a minimally invasive manner, produced superior clinical outcomes, or have become standard of care.

RESULTS

The review provides examples of successful implementations and adoption of image-guided surgical techniques, mostly in the field of neurosurgery. Failures as well as newly developed technologies still undergoing cost-efficacy analysis are discussed.

CONCLUSION

The field of image-guided surgery has evolved from solely using preoperative images to utilizing highly specific tools and software to provide more information to the interventionalist in real time. While deformations in soft tissue often preclude the use of such instruments outside of neurosurgery, recent developments in optical and radioactive guidance have enabled surgeons to better account for organ motion and provide feedback to the surgeon as tissue is cut. These technologies are currently undergoing value assessments in many countries and hold promise to improve outcomes for patients, surgeons, care teams, payors, and society in general.

Robot-assisted fluorescent sentinel lymph node identification in early-stage colon cancer

BACKGROUND

Patients with cT1-2 colon cancer (CC) have a 10-20% risk of lymph node metastases. Sentinel lymph node identification (SLNi) could improve staging and reduce morbidity in future organ-preserving CC surgery. This pilot study aimed to assess safety and feasibility of robot-assisted fluorescence-guided SLNi using submucosally injected indocyanine green (ICG) in patients with cT1-2N0M0 CC.

METHODS

Ten consecutive patients with cT1-2N0M0 CC were included in this prospective feasibility study. Intraoperative submucosal, peritumoral injection of ICG was performed during a colonoscopy. Subsequently, the near-infrared fluorescence 'Firefly' mode of the da Vinci Xi robotic surgical system was used for SLNi. SLNs were marked with a suture, after which a segmental colectomy was performed. The SLN was postoperatively ultrastaged using serial slicing and immunohistochemistry, in addition to the standard pathological examination of the specimen. Colonoscopy time, detection time (time from ICG injection to first SLNi), and total SLNi time were measured (time from the start of colonoscopy to start of segmental resection). Intraoperative, postoperative, and pathological outcomes were registered.

RESULTS

In all patients, at least one SLN was identified (mean 2.3 SLNs, SLN diameter range 1-13 mm). No tracer-related adverse events were noted. Median colonoscopy time was 12 min, detection time was 6 min, and total SLNi time was 30.5 min. Two patients had lymph node metastases present in the SLN, and there were no patients with false negative SLNs. No patient was upstaged due to ultrastaging of the SLN after an initial negative standard pathological examination. Half of the patients unexpectedly had pT3 tumours.

CONCLUSIONS

Robot-assisted fluorescence-guided SLNi using submucosally injected ICG in ten patients with cT1-2N0M0 CC was safe and feasible. SLNi was performed in an acceptable timespan and SLNs down to 1 mm were detected. All lymph node metastases would have been detected if SLN biopsy had been performed.

Navigation-Assisted Surgery for Locally Advanced Primary and Recurrent Rectal Cancer

BACKGROUND

In some surgical disciplines, navigation-assisted surgery has become standard of care, but in rectal cancer, indications for navigation and the utility of different technologies remain undetermined.

METHODS

The NAVI-LARRC prospective study (NCT04512937; IDEAL Stage 2a) evaluated feasibility of navigation in patients with locally advanced primary (LARC) and recurrent rectal cancer (LRRC). Included patients had advanced tumours with high risk of incomplete (R1/R2) resection, and navigation was considered likely to improve the probability of complete resection (R0). Tumours were classified according to pelvic compartmental involvement, as suggested by the Royal Marsden group. The BrainlabTM navigation platform was used for preoperative segmentation of tumour and pelvic anatomy, and for intraoperative navigation with optical tracking. R0 resection rates, surgeons' experiences, and adherence to the preoperative resection plan were assessed.

RESULTS

Seventeen patients with tumours involving the posterior/lateral compartments underwent navigation-assisted procedures. Fifteen patients required abdominosacral resection, and 3 had resection of the sciatic nerve. R0 resection was obtained in 6/8 (75%) LARC and 6/9 (69%) LRRC cases. Preoperative segmentation was time-consuming (median 3.5 h), but intraoperative navigation was accurate. Surgeons reported navigation to be feasible, and adherence to the resection plan was satisfactory.

CONCLUSIONS

Navigation-assisted surgery using optical tracking was feasible. The preoperative planning was time-consuming, but intraoperative navigation was accurate and resulted in acceptable R0 resection rates. Selected patients are likely to benefit from navigation-assisted surgery.

Use of intraoperative bone scintigraphy for resection of spinal osteoid osteoma

BACKGROUND

The location and proximity to the spinal cord in spinal osteoid osteoma can increase the likelihood of an incomplete resection. Intraoperative bone scintigraphy (IOBS) can be used to verify location and complete surgical resection.

OBJECTIVE

To review our experience using IOBS for resection of intraspinal osteoid osteoma.

METHODS

IRB approved, retrospective review of IOBS-guided resection over 10 years. Patients underwent injection of 200 uCi/kg (1-20 mCi) 99mTc-MDP 3-4 h prior surgery. Portable single-headed gamma camera equipped with a pinhole collimator (3- or 4-mm aperture) was used. Images were obtained pre-operatively, at the start of the procedure, and intraoperatively. Operative notes were reviewed. Evaluation of recurrence and clinical follow-up was performed.

RESULTS

Twenty IOBS-guided resections were performed in 18 patients (median age 13.5 years, 6-22 years, 12 males). Size ranged 5-16 mm, with 38.9% (7/18) cervical, 22.2% (4/18) thoracic, 22.2% (4/18) lumbar, and 16.7% (3/18) sacral. In all cases, IOBS was able to localize the lesion. After suspected total excision, IOBS altered the surgical plan in 75% of cases (15/20), showing residual activity prompting further resection. Median length of follow-up was 6 months (range 1-156 months) with 90% (18/20) showing complete resection without recurrence. Two patients had osteoid osteoma recurrence at 7 and 10 months following the original resection, requiring re-intervention.

CONCLUSIONS

IOBS is a useful tool for real-time localization and assessment of spinal osteoid osteoma resection. In all cases, IOBS was able to localize the lesion and changed surgical planning in 75% of cases. Ninety percent of patients achieved complete resection and remain recurrence free.

New hybrid radio-fluorescent probes [131I]-BPF-01 and [131I]-BPF-02 for visualisation of cancer cells: Synthesis and preliminary in vitro and ex vivo evaluations

We synthesised and biologically evaluated two new hybrid probes [131I]BPF-01 and [131I]BPF-02 which were built from three structural entities: benzothiazole-phenyl, fluorescein isothiocyanate (FITC), and iodine-131. These probes were designed for potential applications in assisting surgical procedures of solid cancers. The cytotoxicity study demonstrated that fluorescent probes BPF-01 (31.23 μg/mL) and BPF-02 (250 μg/mL) were relatively not toxic to normal immortalized human keratinocytes (HaCaT) cells, as indicated by the percentage of cell survival above 50 %. Furthermore, both probes displayed low to moderate anticancer activity against the breast cancer cells (MDA-MB-231) and prostate cancer cells (LNCaP and DU-145). The probe BPF-01 apparently showed an accumulation in the tumour tissues, as suggested by ex vivo fluorescence examinations. In addition, the cellular uptake study suggests that hybrid probe [131I]-BPF-01 was potentially accumulated in the MCF-7 cell line with the highest uptake of 16.11 ± 1.52 % after 2 h of incubation, approximately 50-fold higher than the accumulation of iodine-131 (control). The magnetic bead assay suggests that [131I]-BPF-02 and [131I]-BPF-02 showed a promising capability to interact with translocator protein 18 kDa (TSPO). Moreover, the computational data showed that the binding scores for ligands 7-8, BPF-01 and BPF-02, and [131I]-BPF-01 and [131I]-BPF-02 in the TSPO were considerably high. Accordingly, fluorescent probes BPF-01 and BPF-02, and hybrid probes [131I]BPF-01 and [131I]BPF-02 can be further developed for targeting cancer cells during intraoperative tumour surgery.

Audiological outcomes of robot-assisted cochlear implant surgery

PURPOSE

The main objective of this study is to evaluate the short-term and long-term audiological outcomes in patients who underwent cochlear implantation with a robot-assisted system to enable access to the cochlea, and to compare outcomes with a matched control group of patients who underwent cochlear implantation with conventional access to the cochlea.

METHODS

In total, 23 patients were implanted by robot-assisted cochlear implant surgery (RACIS). To evaluate the effectiveness of robotic surgery in terms of audiological outcomes, a statistically balanced control group of conventionally implanted patients was created. Minimal outcome measures (MOM), consisting of pure-tone audiometry, speech understanding in quiet and speech understanding in noise were performed pre-operatively and at 3 months, 6 months, 12 months and 2 years post-activation of the audioprocessor.

RESULTS

There was no statistically significant difference in pure-tone audiometry, speech perception in quiet and speech perception in noise between robotically implanted and conventionally implanted patients pre-operatively, 3 months, 6 months, 12 months and 2 years post-activation. A significant improvement in pure-tone hearing thresholds, speech understanding in quiet and speech understanding in noise with the cochlear implant has been quantified as of the first measurements at 3 months and this significant improvement remained stable over a time period of 2 years for HEARO implanted patients.

CONCLUSION

Clinical outcomes in robot-assisted cochlear implant surgery are comparable to conventional cochlear implantation. CLINICALTRAILS.

GOV TRAIL REGISTRATION NUMBERS

NCT03746613 (date of registration: 19/11/2018), NCT04102215 (date of registration: 25/09/2019).

Drilling accuracy evaluation of a mouldable surgical targeting system for minimally invasive access to anatomic targets in the temporal bone

PURPOSE

Minimally invasive cochlear implant surgery using a micro-stereotactic surgical targeting system with on-site moulding of the template aims for a reliable, less experience-dependent access to the inner ear under maximal reduction of trauma to anatomic structures. We present an accuracy evaluation of our system in ex-vivo testing.

METHODS

Eleven drilling experiments were performed on four cadaveric temporal bone specimens. The process involved preoperative imaging after affixing the reference frame to the skull, planning of a safe trajectory preserving relevant anatomical structures, customization of the surgical template, execution of the guided drilling and postoperative imaging for determination of the drilling accuracy. Deviation between the drilled and desired trajectories was measured at different depths.

RESULTS

All drilling experiments were successfully performed. Other than purposely sacrificing the chorda tympani in one experiment, no other relevant anatomy, such as facial nerve, chorda tympani, ossicles or external auditory canal were harmed. Deviation between the desired and achieved path was found to be 0.25 ± 0.16 mm at skulls' surface and 0.51 ± 0.35 mm at the target level. The closest distance of the drilled trajectories' outer circumference to the facial nerve was 0.44 mm.

CONCLUSIONS

We demonstrated the usability for drilling to the middle ear on human cadaveric specimen in a pre-clinical setting. Accuracy proved to be suitable for many applications such as procedures within the field of image-guided neurosurgery. Promising approaches to reach sufficient submillimetre accuracy for CI surgery have been outlined.

State of the Art in Prostate-specific Membrane Antigen-targeted Surgery-A Systematic Review

Context

Identifying malignant tissue and leaving adjacent structures undisturbed constitute an ongoing challenge in prostate cancer (PCa) surgery. Image and radioguided surgical technologies targeting the prostate-specific membrane antigen (PSMA) receptor may facilitate identification and removal of diseased tissue.

Objective

To perform a systematic review of the clinical studies on PSMA-targeted surgery.

Evidence acquisition

The MEDLINE (OvidSP), Embase.com, and Cochrane Library databases were searched. Identified reports were critically appraised according to the Idea, Development, Exploration, Assessment, Long-term framework criteria. The risk of bias (RoB) was assessed as per the Risk Of Bias In Non-randomized Studies-of Interventions tool. The strengths and limitations of the techniques and corresponding oncological outcomes were extracted as areas of interest. Data were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

Evidence synthesis

In total, 29 reports were selected, including eight prospective studies, 12 retrospective analyses, and nine case reports, all with a high or an unclear RoB. In 72.4% of studies, PSMA targeting was achieved via radioguided surgery (RGS), predominantly using ^99mTc-PSMA-I&S (66.7%). Hybrid approaches that complement RGS with optical guidance are emerging. The majority of studies retrieved were pilot studies with a short follow-up. In 13 reports, salvage lymph node surgery was discussed (44.8%). In 12 more recent reports (41.4%), PSMA targeting was studied in primary PCa surgery (50.0% lymph nodes and 50.0% surgical margins), and four studied both primary and salvage surgery (13.8%). Overall, specificity was higher than sensitivity (median 98.9% and 84.8%, respectively). Oncological outcomes were discussed only in reports on the use of ^99mTc-PSMA-I&S in salvage surgery (median follow-up of 17.2 mo). A decline in prostate-specific antigen level of >90% ranged from 22.0% to 100.0%, and biochemical recurrence ranged from 50.0% to 61.8% of patients.

Conclusions

In PSMA-targeted surgery, most studies address salvage PSMA-RGS using ^99mTc-PSMA-I&S. Available evidence suggests that the specificity of intraoperative PSMA targeting is higher than the sensitivity. The studies that included follow-up did not yet objectify a clear oncological benefit. Lacking solid outcome data, PSMA-targeted surgery remains investigational.

Patient summary

In this paper, we review recent advances in prostate-specific membrane antigen (PSMA)-targeted surgery, which is used to help identify and remove prostate cancer. We found good evidence to suggest that PSMA targeting helps identify prostate cancer during surgery. The oncological benefits have yet to be investigated further.

Implications of navigation in thoracolumbar pedicle screw placement on screw accuracy and screw diameter/pedicle width ratio

Introduction

There is ample evidence that higher accuracy can be achieved in thoracolumbar pedicle screw placement by using spinal navigation. Still, to date, the evidence regarding the influence of the use of navigation on the screw diameter to pedicle width ratio remains limited.

Research question

The aim of this study was to investigate the implications of navigation in thoracolumbar pedicle screw placement not only on screw accuracy, but on the screw diameter to pedicle width ratio as well.

Material and methods

In this single-center single-surgeon study, 45 Patients undergoing navigated thoracolumbar pedicle screw placement were prospectively included. The results were compared with a matched comparison group of patients in which screw placement was performed under fluoroscopic guidance. The screw accuracy and the screw diameter to pedicle width ratio of every screw were compared between the groups.

Results

Screw accuracy was significantly higher in the navigation group compared to the fluoroscopic guidance group, alongside with a significant increase of the screw diameter to pedicle width ratio by approximately 10%. In addition, both the intraoperative radiation dose and the operating time tended to be lower in the study group.

Conclusion

This study was able to show that navigated thoracolumbar pedicle screw placement not only increases the accuracy of screw placement but also facilitates the selection of the adequate screw sizes, which according to the literature has positive effects on fixation strength. Meanwhile, the use of navigation did not negatively affect the time needed for surgery or the patient's intraoperative exposure to radiation.

Comparison of two hybrid sentinel node tracers: indocyanine green (ICG)-99mTc-nanocolloid vs. ICG-99mTc-nanoscan from a nuclear medicine and surgical perspective

BACKGROUND

Lymph node (LN) metastasis is a relevant predictor for survival in patients with a.o. penile cancer (PeCa), malignant melanoma. The sentinel node (SN) procedure comprises targeted resection of the first tumour-draining SNs. Here, the hybrid tracer indocyanine green (ICG)-99mTc-nanocolloid has been used for several years to combine optical and nuclear detection. Recently, the resource of the nanocolloid precursor stopped production and the precursor was replaced by a different but chemically comparable colloid, nanoscan. Our aim was to study the performance of ICG-99mTc-nanoscan compared to ICG-99mTc-nanocolloid from a nuclear and surgical perspective.

METHODS

Twenty-four patients with either PeCa or head-and-neck (H&N) melanoma and scheduled for a SN procedure were included. The initial group (n = 11) received ICG-99mTc-nanocolloid until no longer available; the second group (n = 13) received ICG-99mTc-nanoscan. Tracer uptake was assessed on lymphoscintigraphy and single-photon emission (SPECT). Intraoperatively, SNs were identified using gamma tracing and fluorescence imaging. Ex vivo (back-table) measurements were conducted to quantify the fluorescence emissions. Chemical analysis was performed to compare the ICG assembly on both precursors.

RESULTS

The mean tracer uptake in the SNs was similar for ICG-99mTc-nanocolloid (2.2 ± 4.3%ID) and ICG-99mTc-nanoscan (1.8 ± 2.6%ID; p = 0.68). 3 SNs (interquartile range (IQR) 3-4) were detected on lymphoscintigraphy in PeCa patients receiving ICG-99mTc-nanoscan compared to 2 SNs (IQR 2-3) in PeCa patients receiving ICG-99mTc-nanocolloid (p = 0.045), no differences were observed in H&N patients. Back-table measurements of resected SNs revealed a lower total fluorescence intensity in the ICG-99mTc-nanoscan group (24*109 arbitrary units (A.U) IQR 1.6*109-14*109 in the ICG-99mTc-nanocolloid group versus 4.6*109 A.U. IQR 2.4*109-42*109 in the ICG-99mTc-nanoscan group, p = 0.0054). This was consistent with a larger degree of "stacked" ICG observed in the nanoscan formulation. No tracer-related adverse events were reported.

CONCLUSIONS

Based on this retrospective analysis, we can conclude that ICG-99mTc-nanoscan has similar capacity for SN identification as ICG-99mTc-nanocolloid and can safely be implemented in SN procedures.

A hybrid radioactive and fluorescence approach is more than the sum of its parts; outcome of a phase II randomized sentinel node trial in prostate cancer patients

OBJECTIVE

To determine the diagnostic accuracy of the hybrid tracer indocyanine green (ICG)-Technetium-99 m(99mTc)-nanocolloid compared to sequential tracers of 99mTc-nanocolloid and free-ICG in detecting tumor-positive lymph nodes (LN) during primary surgery in prostate cancer (PCa) patients.

INTRODUCTION

Image-guided surgery strategies can help visualize individual lymphatic drainage patterns and sentinel lymph nodes (SLNs) in PCa patients. For lymphatic mapping radioactive, fluorescent and hybrid tracers are being clinically exploited. In this prospective randomized phase II trial, we made a head-to-head comparison between ICG-99mTc-nanocolloid (hybrid group) and 99mTc-nanocolloid and subsequent free-ICG injection (sequential group).

METHODS

PCa patients with a  >5% risk of lymphatic involvement according to the 2012 Briganti nomogram and planned for prostatectomy were included and randomized (1:1) between ultrasound-guided intraprostatic tracer administration of ICG-99mTc-nanocolloid (n = 69) or 99mTc-nanocolloid (n = 69) 5 h before surgery. Preoperative lymphoscintigraphy and SPECT/CT were performed to define the locations of the SLNs. Additionally, all participants in the sequential group received an injection of free-ICG at time of surgery. Subsequently, all (S)LNs were dissected using fluorescence guidance followed by an extended pelvic lymph node dissection (ePLND). The primary outcome was the total number of surgically removed (S)LNs and tumor-positive (S)LNs.

RESULTS

The total number of surgically removed (S)LN packages was 701 and 733 in the hybrid and sequential groups, respectively (p = 0.727). The total number of fluorescent LNs retrieved was 310 and 665 nodes in the hybrid and sequential groups, respectively (p < 0.001). However, no statistically significant difference was observed in the corresponding number of tumor-positive nodes among the groups (44 vs. 33; p = 0.470). Consequently, the rate of tumor-positive fluorescent LNs was higher in the hybrid group (7.4%) compared to the sequential group (2.6%; p = 0.002), indicating an enhanced positive predictive value for the hybrid approach. There was no difference in complications within 90 days after surgery (p = 0.78).

CONCLUSIONS

The hybrid tracer ICG-99mTc-nanocolloid improved the positive predictive value for tumor-bearing LNs while minimizing the number of fluorescent nodes compared to the sequential tracer approach. Consequently, the hybrid tracer ICG-99mTc-nanocolloid enables the most reliable and minimal invasive method for LN staging in PCa patients.

Visualization in 2D/3D registration matters for assuring technology-assisted image-guided surgery

PURPOSE

Image-guided navigation and surgical robotics are the next frontiers of minimally invasive surgery. Assuring safety in high-stakes clinical environments is critical for their deployment. 2D/3D registration is an essential, enabling algorithm for most of these systems, as it provides spatial alignment of preoperative data with intraoperative images. While these algorithms have been studied widely, there is a need for verification methods to enable human stakeholders to assess and either approve or reject registration results to ensure safe operation.

METHODS

To address the verification problem from the perspective of human perception, we develop novel visualization paradigms and use a sampling method based on approximate posterior distribution to simulate registration offsets. We then conduct a user study with 22 participants to investigate how different visualization paradigms (Neutral, Attention-Guiding, Correspondence-Suggesting) affect human performance in evaluating the simulated 2D/3D registration results using 12 pelvic fluoroscopy images.

RESULTS

All three visualization paradigms allow users to perform better than random guessing to differentiate between offsets of varying magnitude. The novel paradigms show better performance than the neutral paradigm when using an absolute threshold to differentiate acceptable and unacceptable registrations (highest accuracy: Correspondence-Suggesting (65.1%), highest F1 score: Attention-Guiding (65.7%)), as well as when using a paradigm-specific threshold for the same discrimination (highest accuracy: Attention-Guiding (70.4%), highest F1 score: Corresponding-Suggesting (65.0%)).

CONCLUSION

This study demonstrates that visualization paradigms do affect the human-based assessment of 2D/3D registration errors. However, further exploration is needed to understand this effect better and develop more effective methods to assure accuracy. This research serves as a crucial step toward enhanced surgical autonomy and safety assurance in technology-assisted image-guided surgery.

True keyhole cochlear implant surgery

INTRODUCTION

Minimal invasive Robotic Assisted Cochlear Implant Surgery (RACIS) is a keyhole surgery by definition. It is therefore not possible to visualize the electrode array during insertion in the scala tympani. Hitherto, surgeons visualised the round window via the external auditory canal by folding over the tympanic membrane. However, the opening of a tympanomeatal flap is not minimal invasive and is especially in conventional cochlear implantation surgery not even necessary. Here we prove that image guided and robot assisted surgery can also allow correct electrode array insertion without opening the tympanomeatal flap.

AIM

The aim is to report the first experience of robotic cochlear implantation surgery fully based on image guided surgery and without the opening of a tympanomeatal flap for electrode array insertion.

INTERVENTION

RACIS with a straight flexible lateral wall electrode.

PRIMARY OUTCOME MEASUREMENTS

Electrode cochlear insertion depth with RACIS and autonomous inner ear access with full electrode insertion of a flexible lateral wall electrode array.

SECONDARY OUTCOME MEASUREMENTS

The audiological outcome in terms of mean hearing thresholds.

CONCLUSION

After a series of 33 cases and after fine-tuning the insertion angles and yet another new version of planning software to depict the round window approach, a new clinical routine for inserting electrodes fully based on image guided surgery without opening a tympanomeatal flap was developed in robotic-assisted cochlear implant surgery.

Intraoperative zoom lens calibration for high magnification surgical microscope

BACKGROUND AND OBJECTIVES

An augmented reality (AR)-based surgical guidance system is often used with high-magnification zoom lens systems such as a surgical microscope, particularly in neurology or otolaryngology. To superimpose the internal structures of relevant organs on the microscopy image, an accurate calibration process to obtain the camera intrinsic and hand-eye parameters of the microscope is essential. However, conventional calibration methods are unsuitable for surgical microscopes because of their narrow depth of focus at high magnifications. To realize AR-based surgical guidance with a high-magnification surgical microscope, we herein propose a new calibration method that is applicable to the highest magnification levels as well as low magnifications.

METHODS

The key idea of the proposed method is to find the relationship between the focal length and the hand-eye parameters, which remains constant regardless of the magnification level. Based on this, even if the magnification changes arbitrarily during surgery, the intrinsic and hand-eye parameters are recalculated quickly and accurately with one or two pictures of the pattern. We also developed a dedicated calibration tool with a prism to take focused pattern images without interfering with the surgery.

RESULTS

The proposed calibration method ensured an AR error of < 1 mm for all magnification levels. In addition, the variation of focal length was within 1% regardless of the magnification level, and the corresponding variation with the conventional calibration method exceeded 20% at high magnification levels.

CONCLUSIONS

The comparative study showed that the proposed method has outstanding accuracy and reproducibility for a high-magnification surgical microscope. The proposed calibration method is applicable to various endoscope or microscope systems with zoom lens.

Image-guided cancer surgery: a narrative review on imaging modalities and emerging nanotechnology strategies

Surgical resection is the cornerstone of solid tumour treatment. Current techniques for evaluating margin statuses, such as frozen section, imprint cytology, and intraoperative ultrasound, are helpful. However, an intraoperative assessment of tumour margins that is accurate and safe is clinically necessary. Positive surgical margins (PSM) have a well-documented negative effect on treatment outcomes and survival. As a result, surgical tumour imaging methods are now a practical method for reducing PSM rates and improving the efficiency of debulking surgery. Because of their unique characteristics, nanoparticles can function as contrast agents in image-guided surgery. While most image-guided surgical applications utilizing nanotechnology are now in the preclinical stage, some are beginning to reach the clinical phase. Here, we list the various imaging techniques used in image-guided surgery, such as optical imaging, ultrasound, computed tomography, magnetic resonance imaging, nuclear medicine imaging, and the most current developments in the potential of nanotechnology to detect surgical malignancies. In the coming years, we will see the evolution of nanoparticles tailored to specific tumour types and the introduction of surgical equipment to improve resection accuracy. Although the promise of nanotechnology for producing exogenous molecular contrast agents has been clearly demonstrated, much work remains to be done to put it into practice.

Acidic tumor microenvironment-activatable fluorescent diagnostic probe for the rapid identification and resection of human tumors via spraying

A fluorescent diagnostic probe for real-time intraoperative image-guided tumor resection can significantly improve the efficiency and quality of oncological therapy, but their development is challenging. Herein, a novel fluorescent diagnostic probe called HLTC based on β-carboline was designed and synthesized. HLTC was found to show a ∼10-fold enhancement of fluorescence quantum field with pH from 7.4 to 4.0, indicating its imaging potential in acid environment which is a typical hallmark of the tumor microenvironment (TME). Following fluorescence microscopy imaging showed HLTC could emit specific signals in cancer cells and sections, by both one-photon excitation and two-photon excitation. Importantly, HLTC enabled the precise and rapid delineation of both transplanted tumor and clinical tumor tissues within several minutes of simple topical spray. The tumor-to-background ratio (TBR) was up to 10.2 ± 1.0 at clinical liver cancer tissues and 9.9 ± 0.3 at clinical colon cancer tissues, allowing precise tumor margin identification and the effective guidance of surgical tumor resection. Furthermore, CCK8 assay, pharmacokinetic evaluation, blood analysis and H&E staining were performed, which verified high biocompatibility and biosafety of HLTC at working concentration. These results reveal the exciting potential of this small-molecule fluorescent diagnostic probe for real-time fluorescence-based navigation during surgical tumor resection.

Evaluation of Preoperative and Intraoperative Mobile Gamma Camera Imaging in Sentinel Lymph Node Biopsy for Melanoma Independent of Preoperative Lymphoscintigraphy

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is a standard practice for staging cutaneous melanoma. High false-negative rates have an increased interest in adjunctive techniques for localizing SLNs. Mobile gamma cameras (MGCs) represent potential tools to enhance SLNB performance.

METHODS

An institutional review board approval was obtained for this study (ClinicalTrials.gov ID NCT01531608). After obtaining informed consent, 20 eligible melanoma patients underwent ^99mTc sulfur colloid injection and standard lymphoscintigraphy with a fixed gamma camera (FGC). A survey using a 20 cm square MGC, performed immediately preoperatively by the study surgeon, was used to establish an operative plan while blinded to the FGC results. Subsequently, SLNB was performed using a gamma probe and a novel 6 cm diameter handheld MGC.

RESULTS

A total of 24 SLN basins were detected by FGC. Prior to unblinding, all 24 basins were identified with the preoperative MGC and the operative plan established by preoperative MGC imaging was confirmed accurate by review of the FGC images. All individual sentinel lymph nodes were identified during intraoperative MGC imaging, and in 5/24 (21%) cases, surgeon-reported additional clinically useful information was obtained from the MGC.

CONCLUSIONS

Preoperative MGC images provide information consistent with FGC images for planning SLNB and in some cases provide additional information that aided in surgical decision-making.

A Safe Framework for Quantitative In Vivo Human Evaluation of Image Guidance

Goal: We present a new framework for in vivo image guidance evaluation and provide a case study on robotic partial nephrectomy. Methods: This framework (called the "bystander protocol") involves two surgeons, one who solely performs the therapeutic process without image guidance, and another who solely periodically collects data to evaluate image guidance. This isolates the evaluation from the therapy, so that in-development image guidance systems can be tested without risk of negatively impacting the standard of care. We provide a case study applying this protocol in clinical cases during robotic partial nephrectomy surgery. Results: The bystander protocol was performed successfully in 6 patient cases. We find average lesion centroid localization error with our IGS system to be 6.5 mm in vivo compared to our prior result of 3.0 mm in phantoms. Conclusions: The bystander protocol is a safe, effective method for testing in-development image guidance systems in human subjects.

Computer-based airway stenosis quantification from bronchoscopic images: preliminary results from a feasibility trial

PURPOSE

Airway Stenosis (AS) is a condition of airway narrowing in the expiration phase. Bronchoscopy is a minimally invasive pulmonary procedure used to diagnose and/or treat AS. The AS quantification in a form of the Stenosis Index (SI), whether subjective or digital, is necessary for the physician to decide on the most appropriate form of treatment. The literature reports that the subjective SI estimation is inaccurate. In this paper, we propose an approach to quantify the SI defining the level of airway narrowing, using depth estimation from a bronchoscopic image.

METHODS

In this approach we combined a generative depth estimation technique combined with depth thresholding to provide Computer-based AS quantification. We performed an interim clinical analysis by comparing AS quantification performance of three expert bronchoscopists against the proposed Computer-based method on seven patient datasets.

RESULTS

The Mean Absolute Error of the subjective Human-based and the proposed Computer-based SI estimation was [Formula: see text] [%] and [Formula: see text] [%], respectively. The correlation coefficients between the CT measurements were used as the gold standard, and the Human-based and Computer-based SI estimation were [Formula: see text] and 0.46, respectively.

CONCLUSIONS

We presented a new computer method to quantify the severity of AS in bronchoscopy using depth estimation and compared the performance of the method against a human-based approach. The obtained results suggest that the proposed Computer-based AS quantification is a feasible tool that has the potential to provide significant assistance to physicians in bronchoscopy.

Innovative Imaging Techniques Used to Evaluate Borderline-Resectable Pancreatic Adenocarcinoma

A diagnosis of pancreatic cancer carries a 5-y survival rate of less than 10%. Furthermore, the detection of pancreatic cancer occurs most often in later stages of the disease due to its location in the retroperitoneum and lack of symptoms (in most cases) until tumors become more advanced. Once diagnosed, cross-sectional imaging techniques are heavily utilized to determine the tumor stage and the potential for surgical resection. However, a major determinant of resectability is the extent of local vascular involvement of the mesenteric vessels and critical tributaries; current imaging techniques have limited capacity to accurately determine vascular involvement. Surrounding inflammation and fibrosis can be difficult to discriminate from viable tumor, making determination of the degree of vascular involvement unreliable. New innovations in fluorescence and optoacoustic imaging techniques may overcome these limitations and make determination of resectability more accurate. These imaging modalities are able to more clearly discern between viable tumor tissue and non-neoplastic inflammation or desmoplasia, allowing clinicians to more reliably characterize vascular involvement and develop individualized treatment plans for patients. This review will discuss the current imaging techniques used to diagnose pancreatic cancer, the barriers that current techniques raise to accurate staging, and novel fluorescence and optoacoustic imaging techniques that may provide more accurate clinical staging of pancreatic cancer.

Fibronectin-targeting and metalloproteinase-activatable smart imaging probe for fluorescence imaging and image-guided surgery of breast cancer

Residual lesions in the tumor bed have been a challenge for conventional white-light breast-conserving surgery. Meanwhile, lung micro-metastasis also requires improved detection methods. Intraoperative accurate identification and elimination of microscopic cancer can improve surgery prognosis. In this study, a smart fibronectin-targeting and metalloproteinase-activatable imaging probe CREKA-GK8-QC is developed. CREKA-GK8-QC possesses an average diameter of 21.7 ± 2.5 nm, excellent MMP-9 protein responsiveness and no obvious cytotoxicity. In vivo experiments demonstrate that NIR-I fluorescence imaging of CREKA-GK8-QC precisely detects orthotopic breast cancer and micro-metastatic lesions (nearly 1 mm) of lungs with excellent imaging contrast ratio and spatial resolution. More notably, fluorescence image-guided surgery facilitates complete resection and avoids residual lesions in the tumor bed, improving survival outcomes. We envision that our newly developed imaging probe shows superior capacity for specific and sensitive targeted imaging, as well as providing guidance for accurate surgical resection of breast cancer.

Accuracy of computer-aided static and dynamic navigation systems in the placement of zygomatic dental implants

BACKGROUND

Zygomatic implants are widely used in the rehabilitation of severely atrophic maxillae, but implant placement is not without risks, and it can potentially cause damage to related anatomical structures. The aim of this study was to perform a comparative analysis of the accuracy of static navigation systems in placing zygomatic dental implants in comparison to dynamic navigation systems.

METHODS

Sixty zygomatic dental implants were randomly allocated to one of three study groups, categorized by which implant placement strategy was used: A: computer-aided static navigation system (n = 20) (GI); B: computer-aided dynamic navigation system (n = 20) (NI); or C: free-hand technique (n = 20) (FHI). For the computer-aided study groups, a preoperative cone-beam computed tomography (CBCT) scan of the existing situation was performed in order to plan the approach to be used during surgery. Four zygomatic dental implants were inserted in each of fifteen polyurethane stereolithographic models (n = 15), with a postoperative CBCT scan taken after the intervention. The pre- and postoperative CBCT scans were then uploaded to a software program used in dental implantology to analyze the angular deviations, apical end point, and coronal entry point. Student's t-test was used to analyze the results.

RESULTS

The results found statistically significant differences in apical end-point deviations between the FHI and NI (p = 0.0053) and FHI and GI (p = 0.0004) groups. There were also statistically significant differences between the angular deviations of the FHI and GI groups (p = 0.0043).

CONCLUSIONS

The manual free-hand technique may enable more accurate placement of zygomatic dental implants than computer-assisted surgical techniques due to the different learning curves required for each zygomatic dental implant placement techniques.

Influence of alveolar ridge morphology and guide-hole design on the accuracy of static Computer-Assisted Implant Surgery with two implant macro-designs: An in vitro study

OBJECTIVES

The primary aim of this in vitro study was to evaluate the influence of alveolar ridge morphologies on the accuracy of static Computer-Assisted Implant Surgery (sCAIS). The secondary aims were to evaluate the influence of guide-hole design and implant macro-design on the accuracy of the final implant position.

METHODS

Eighteen standardized partially edentulous maxillary models with two different types of alveolar ridge morphologies were used. Each model was scanned via cone beam computer tomography prior to implant placement and scanned with a laboratory scanner prior to and following implant placement using sCAIS. The postsurgical scans were superimposed on the initial treatment planning position to measure the deviations between planned and postsurgical implant positions.

RESULTS

Seventy-two implants were equally distributed to the study groups. Implants placed in healed alveolar ridges showed significantly lower mean deviations at the crest (0.36 ± 0.17 mm), apex (0.69 ± 0.36 mm), and angular deviation (1.86 ± 0.99°), compared to implants placed in fresh extraction sites (0.80 ± 0.29 mm, 1.61 ± 0.59 mm, and 4.33 ± 1.87°; all p<0.0001). Implants placed with a sleeveless guide-hole design demonstrated significantly lower apical (1.02 ± 0.66 mm) and angular (2.72 ± 1.93°) deviations compared to those placed with manufacturer's sleeves (1.27 ± 0.67 mm; p = 0.01, and 3.46 ± 1.9°; p = 0.02). Deep-threaded tapered bone level implants exhibited significantly lower deviations at the crest (0.49 ± 0.28 mm), apex (0.97 ± 0.63 mm), and angular deviations (2.63 ± 1.85°) compared to shallow-threaded parallel-walled bone level implants (0.67 ± 0.34 mm; p = 0.0005, 1.32 ± 0.67 mm; p = 0.003, and 3.56 ± 1.93°; p = 0.01).

CONCLUSIONS

The accuracy of the final implant position with sCAIS is determined by the morphology of the alveolar ridge, the design of the guide holes, and the macrodesign of the implant.

CLINICAL SIGNIFICANCE

Higher accuracy in the final implant position was observed with implants placed in healed alveolar ridge morphologies, in implants with deep-threaded tapered macro-design, and when sleeveless surgical guide holes were used.

Quantification of bowel ischaemia using real-time multispectral Single Snapshot Imaging of Optical Properties (SSOP)

BACKGROUND

Single snapshot imaging of optical properties (SSOP) is a relatively new non-invasive, real-time, contrast-free optical imaging technology, which allows for the real-time quantitative assessment of physiological properties, including tissue oxygenation (StO2). This study evaluates the accuracy of multispectral SSOP in quantifying bowel ischaemia in a preclinical experimental model.

METHODS

In six pigs, an ischaemic bowel segment was created by dividing the arcade branches. Five regions of interest (ROIs) were identified on the bowel loop, as follows: ROI 1: central ischaemic; ROI 2: left marginal; ROI 3: left vascularised; ROI 4: right marginal; and ROI 5: right vascularised. The Trident imaging system, specifically developed for real-time tissue oxygenation imaging using SSOP, was used to image before (T0) and after ischaemia induction. Capillary and systemic lactates were measured at each time point (T0, T15, T30, T45, T60), as well as StO2 values acquired by means of SSOP (SSOP-StO2).

RESULTS

The mean value of SSOP-StO2 in ROI 1 was 30.08 ± 6.963 and was significantly lower when compared to marginal ROIs (ROI 2 + ROI 4: 45.67 ± 10.02 p =  < 0.0001), and to vascularised ROIs (ROI 3 + ROI 5: 48.08 ± 7.083 p =  < 0.0001). SSOP-StO2 was significantly correlated with normalised lactates r = - 0.5892 p < 0.0001 and with histology r =- 0.6251 p = 0.0002.

CONCLUSION

Multispectral SSOP allows for a contrast-free accurate assessment of small bowel perfusion identifying physiological tissue oxygenation as confirmed with perfusion biomarkers.

Surface deformation tracking in monocular laparoscopic video

Image-guided surgery has been proven to enhance the accuracy and safety of minimally invasive surgery (MIS). Nonrigid deformation tracking of soft tissue is one of the main challenges in image-guided MIS owing to the existence of tissue deformation, homogeneous texture, smoke and instrument occlusion, etc. In this paper, we proposed a piecewise affine deformation model-based nonrigid deformation tracking method. A Markov random field based mask generation method is developed to eliminate tracking anomalies. The deformation information vanishes when the regular constraint is invalid, which further deteriorates the tracking accuracy. Atime-series deformation solidification mechanism is introduced to reduce the degradation of the deformation field of the model. For the quantitative evaluation of the proposed method, we synthesized nine laparoscopic videos mimicking instrument occlusion and tissue deformation. Quantitative tracking robustness was evaluated on the synthetic videos. Three real videos of MIS containing challenges of large-scale deformation, large-range smoke, instrument occlusion, and permanent changes in soft tissue texture were also used to evaluate the performance of the proposed method. Experimental results indicate the proposed method outperforms state-of-the-art methods in terms of accuracy and robustness, which shows good performance in image-guided MIS.

Functionalized polydopamine nanospheres as in situ spray for photothermal image-guided tumor precise surgical resection

Surgical resection is a critical procedure for treatment of solid tumor, which commonly suffers from postoperative local recurrence due to the possibility of positive surgical margin. Although the widely used clinical imaging techniques (CT, MRI, PET, etc.) show beneficial effects in providing a macroscopic view of preoperative tumor position, they are still failing to provide intraoperative real-time imaging navigation during the surgery and need oral or intravenous injection contrast agents with risk of adverse effects. In this work, we present a nano-spray assisted photothermal imaging system for in vitro cells discrimination as well as in vivo visualization of tumor position and border that guides real-time precise tumor resection during surgery (even for tiny tumor less than 3 mm). Herein, the nano-spray were prepared by RGD peptide functionalized polydopamine (PDA-RGD) nanospheres with excellent photothermal conversion efficiency (54.27%), stability and reversibility, which target ανβ3 integrin overexpressed tumor cells. Such PDA-RGD serve as nanothermometers that convert and amplify biological signal to intuitive thermal image signal, depicting the tumor margin in situ. In comparison to conventional imaging techniques, our approach through topical spraying together with portable infrared camera has the characteristics of low cost, convenient, no radiation hazard, real-time intraoperative imaging-guidance and avoiding the adverse effects risk of oral or intravenous contrast agent. This technology provides a new universal tool for potentially assisting surgeons' decision in real-time during surgery and aiding to improved outcome.

Accuracy of keyless vs drill-key implant systems for static computer-assisted implant surgery using two guide-hole designs compared to freehand implant placement: an in vitro study

PURPOSE

This in vitro study aimed at comparing the accuracy of freehand implant placement with static computer-assisted implant surgery (sCAIS), utilizing a keyless and a drill-key implant system and two guide-hole designs.

METHODS

A total of 108 implants were placed in 18 partially edentulous maxillary models simulating two different alveolar ridge morphologies. 3D digital deviations between pre-planned and post-operative implant positions were obtained. Guide material reduction was assessed in the keyless implant system for the manufacturer's sleeve and sleeveless guide-hole designs.

RESULTS

sCAIS using a sleeveless guide-hole design demonstrated smaller mean angular, crestal and apical deviations compared to sCAIS utilizing a manufacturer's sleeve and the freehand group (2.6 ± 1.6°, vs 3.3 ± 1.9°, vs 4.0 ± 1.9°; 0.5 ± 0.3 mm, vs 0.6 ± 0.3 mm, vs 0.8 ± 0.3 mm; and 1.0 ± 0.5 mm, vs 1.2 ± 0.7 mm, vs 1.5 ± 0.6 mm). Smaller angular and apical mean deviations were observed in the keyless implant system as compared with the drill-key implant system (3.1 ± 1.7°, vs 3.5 ± 1.9°, p = 0.03; and 1.2 ± 0.6 mm, vs 1.4 ± 0.7 mm, p = 0.045). Overall, smaller angular, crestal, and apical deviations (p < 0.0001) were observed in healed alveolar ridges (2.4 ± 1.7°, 0.5 ± 0.3 mm, and 0.9 ± 0.5 mm) than in extraction sockets (4.2 ± 1.6°, 0.8 ± 0.3 mm, and 1.6 ± 0.5 mm). Higher mean volumetric material reduction was observed in sleeveless than in manufacturer's sleeve guide-holes (- 0.10 ± 0.15 mm³, vs - 0.03 ± 0.03 mm³, p = 0.006).

CONCLUSIONS

Higher final implant positional accuracy was observed in sCAIS for the keyless implant system, with a sleeveless guide-hole design, and in healed ridges. Sleeveless guide holes resulted in higher volumetric material reduction compared with the manufacturer's sleeve.