Calibration-free structured-light-based 3D scanning system in laparoscope for robotic surgery

Accurate 3D shape measurement is crucial for surgical support and alignment in robotic surgery systems. Stereo cameras in laparoscopes offer a potential solution; however, their accuracy in stereo image matching diminishes when the target image has few textures. Although stereo matching with deep learning has gained significant attention, supervised learning requires a large dataset of images with depth annotations, which are scarce for laparoscopes. Thus, there is a strong demand to explore alternative methods for depth reconstruction or annotation for laparoscopes. Active stereo techniques are a promising approach for achieving 3D reconstruction without textures. In this study, a 3D shape reconstruction method is proposed using an ultra-small patterned projector attached to a laparoscopic arm to address these issues. The pattern projector emits a structured light with a grid-like pattern that features node-wise modulation for positional encoding. To scan the target object, multiple images are taken while the projector is in motion, and the relative poses of the projector and a camera are auto-calibrated using a differential rendering technique. In the experiment, the proposed method is evaluated by performing 3D reconstruction using images obtained from a surgical robot and comparing the results with a ground-truth shape obtained from X-ray CT.

Scale-preserving shape reconstruction from monocular endoscope image sequences by supervised depth learning

Reconstructing 3D shapes from images are becoming popular, but such methods usually estimate relative depth maps with ambiguous scales. A method for reconstructing a scale-preserving 3D shape from monocular endoscope image sequences through training an absolute depth prediction network is proposed. First, a dataset of synchronized sequences of RGB images and depth maps is created using an endoscope simulator. Then, a supervised depth prediction network is trained that estimates a depth map from a RGB image minimizing the loss compared to the ground-truth depth map. The predicted depth map sequence is aligned to reconstruct a 3D shape. Finally, the proposed method is applied to a real endoscope image sequence.

Towards better laparoscopic video segmentation: A class-wise contrastive learning approach with multi-scale feature extraction

The task of segmentation is integral to computer-aided surgery systems. Given the privacy concerns associated with medical data, collecting a large amount of annotated data for training is challenging. Unsupervised learning techniques, such as contrastive learning, have shown powerful capabilities in learning image-level representations from unlabelled data. This study leverages classification labels to enhance the accuracy of the segmentation model trained on limited annotated data. The method uses a multi-scale projection head to extract image features at various scales. The partitioning method for positive sample pairs is then improved to perform contrastive learning on the extracted features at each scale to effectively represent the differences between positive and negative samples in contrastive learning. Furthermore, the model is trained simultaneously with both segmentation labels and classification labels. This enables the model to extract features more effectively from each segmentation target class and further accelerates the convergence speed. The method was validated using the publicly available CholecSeg8k dataset for comprehensive abdominal cavity surgical segmentation. Compared to select existing methods, the proposed approach significantly enhances segmentation performance, even with a small labelled subset (1-10%) of the dataset, showcasing a superior intersection over union (IoU) score.

Towards navigation in endoscopic kidney surgery based on preoperative imaging

Endoscopic renal surgeries have high re-operation rates, particularly for lower volume surgeons. Due to the limited field and depth of view of current endoscopes, mentally mapping preoperative computed tomography (CT) images of patient anatomy to the surgical field is challenging. The inability to completely navigate the intrarenal collecting system leads to missed kidney stones and tumors, subsequently raising recurrence rates. A guidance system is proposed to estimate the endoscope positions within the CT to reduce re-operation rates. A Structure from Motion algorithm is used to reconstruct the kidney collecting system from the endoscope videos. In addition, the kidney collecting system is segmented from CT scans using 3D U-Net to create a 3D model. The two collecting system representations can then be registered to provide information on the relative endoscope position. Correct reconstruction and localization of intrarenal anatomy and endoscope position is demonstrated. Furthermore, a 3D map is created supported by the RGB endoscope images to reduce the burden of mental mapping during surgery. The proposed reconstruction pipeline has been validated for guidance. It can reduce the mental burden for surgeons and is a step towards the long-term goal of reducing re-operation rates in kidney stone surgery.

ASSIST-U: A system for segmentation and image style transfer for ureteroscopy

Kidney stones require surgical removal when they grow too large to be broken up externally or to pass on their own. Upper tract urothelial carcinoma is also sometimes treated endoscopically in a similar procedure. These surgeries are difficult, particularly for trainees who often miss tumours, stones or stone fragments, requiring re-operation. Furthermore, there are no patient-specific simulators to facilitate training or standardized visualization tools for ureteroscopy despite its high prevalence. Here a system ASSIST-U is proposed to create realistic ureteroscopy images and videos solely using preoperative computerized tomography (CT) images to address these unmet needs. A 3D UNet model is trained to automatically segment CT images and construct 3D surfaces. These surfaces are then skeletonized for rendering. Finally, a style transfer model is trained using contrastive unpaired translation (CUT) to synthesize realistic ureteroscopy images. Cross validation on the CT segmentation model achieved a Dice score of 0.853 ± 0.084. CUT style transfer produced visually plausible images; the kernel inception distance to real ureteroscopy images was reduced from 0.198 (rendered) to 0.089 (synthesized). The entire pipeline from CT to synthesized ureteroscopy is also qualitatively demonstrated. The proposed ASSIST-U system shows promise for aiding surgeons in the visualization of kidney ureteroscopy.

Extended endoscopic endonasal approach to the chiasmatic cistern: An anatomical study of the arachnoid

This paper studied the arachnoid of the chiasmatic cistern (CC) and the methods for increasing the exposure of the CC from an endoscopic perspective. Eight anatomical specimens with vascular injection were used for endoscopic endonasal dissection. The anatomical characteristics of the CC were studied and documented, and anatomical measurements were collected. The CC is an unpaired five-walled arachnoid cistern located between the optic nerve, optic chiasm, and the diaphragma sellae. The average exposed area of the CC before the anterior intercavernous sinus (AICS) was transected was 66.67 ± 33.76 mm2 . After the AICS was transected and the pituitary gland (PG) was mobilized, the average exposed area of the CC was 95.90 ± 45.48 mm2 . The CC has five walls and a complex neurovascular structure. It is located in a critical anatomical position. The transection of the AICS and mobilization of the PG or the selective sacrifice of the descending branch of the superior hypophyseal artery can improve the operative field.

Evaluation of a novel disposable endoscope for retroflexed endoscopic rubber band ligation of internal hemorrhoids: a randomized pilot study

PURPOSE

Retroflexed endoscopic rubber band ligation (ERBL) for treating Grade II and III internal hemorrhoids using disposable endoscopes has not been previously assessed. We therefore compared the safety and effectiveness of ERBL for internal hemorrhoids using novel disposable endoscopes versus traditional reusable endoscopes.

METHODS

This prospective randomized controlled trial involved 42 patients who underwent ERBL for Grade II and III internal hemorrhoids using either a disposable endoscope (n = 21) or a reusable endoscope (n = 21). Safety was assessed by the incidence of equipment failure, device-related adverse events, and in-procedure stability of vital signs. Effectiveness was assessed by the postoperative therapeutic effect, feasibility of retroflexed ERBL, and incidence of complications.

RESULTS

In terms of safety, no life-threatening events, equipment failure, or device-related adverse effects occurred during the procedures in either group. The rate of diastolic blood pressure stability was significantly different between the two groups (P = .049), but the rates of systolic blood pressure and heart rate stability were similar. In terms of effectiveness, the therapeutic effects on postoperative Day 30 were similar in both groups. Image clarity and endoscopic flexibility in the disposable endoscope group were mildly inferior to those in the reusable endoscope group, but without statistical significance. Matching between the endoscope and ligating device was 100% in both groups. The incidence of complications on postoperative Days 1 and 10 was not significantly different between the two groups.

CONCLUSION

Compared with reusable endoscopes, disposable endoscopes are equally safe, feasible, and reliable in ERBL for internal hemorrhoids.

The Value of the Endoscope-Holding Arm in Transoral Pharyngeal Surgery

BACKGROUND

Transoral pharyngeal surgery is mainly feasible with the use of a microscope or robotic systems. Data about alternative methods, with lower costs and easier availability, are sparse. We intended to examine to what extent the endoscope-holding arm is a suitable alternative to the microscope or robotic systems.

MATERIAL AND METHODS

We retrospectively reviewed subjects who underwent pharyngeal tumor resection with the endoscope-holding arm in our university department.

RESULTS

We identified 13 subjects who underwent transoral pharyngeal surgery between November 2020 and November 2023. Most subjects presented with an oropharyngeal tumor (6/11 in the lateral wall or tonsil; 4/11 in the tongue base). The oropharyngeal lateral wall or tonsillar tumors were exposed with a standard mouth gag. The tongue-base tumors or hypopharyngeal tumors were exposed with an operating laryngoscope. Advantages over the microscope included an angled view. Advantages over robotic systems included haptic feedback and a faster setup. Advantages over both the microscope and robotic systems included lower costs and easier availability. Visualization with the endoscope was sufficient and similar to that of the microscope. Bimanual action was possible with surgical forceps and a monopolar electrode.

CONCLUSIONS

Transoral pharyngeal surgery was feasible with the endoscope-holding arm. The endoscope-holding arm could be a cost-efficient alternative to the microscope or robotic systems.

Global Trends and Hotspots of Minimally Invasive Surgery in Lumbar Spinal Stenosis: A Bibliometric Analysis

Objective

The popularity of minimally invasive surgery for lumbar spinal stenosis (LSS) has been steadily increasing worldwide. This study aims to conduct a comprehensive bibliometric analysis to identify global trends and hotspots in the research related to this surgical approach.

Methods

Select articles related to the field that were retrieved from the Web of Science Core Collection (WoSCC) between January 1, 1993 and December 31, 2022. Visualization of networks and in-depth bibliometric analyses, including the number of publications, countries/regions, institutions, journals, authors, keywords, and references, were conducted using VOSviewer and CiteSpace software.

Results

A total of 1197 papers were identified over a three-decade period, with the highest production year being 2022, which saw 171 papers published. The most prolific countries/regions were the United States (279) and Harvard Medical School (59). Among journals, Spine (3289 citations) was the most cited, while World Neurosurgery (98 publications) had the highest number of publications. Lewandrowski, Kai-Uwe (29 publications) wrote the most articles, and Ahn, Y (239 citations) ranked first among cited authors. The most frequently used keyword was "discectomy", but recent years have shown a strong emergence of keywords such as "microendoscopic decompressive laminotomy", "foraminotomy" and "classification".

Conclusion

The United States and China have emerged as leaders in the field of minimally invasive surgery for LSS. Endoscopic spinal surgery is recognized as a critical approach, with ongoing research focused on indications, potential complications, minimally invasive anatomical approaches, and outcomes. Furthermore, there is a strong emphasis on optimizing the surgical process, which has become a trending and hot spot in current research. The improvement of surgical techniques is at the forefront of advancements in this field.

Is ultraviolet light disinfection fit to be the future standard for the disinfection of flexible endoscopes without a working channel?

OBJECTIVE

To investigate colony-forming unit (CFU) reduction on contaminated flexible endoscopes (FEs) without a working channel after UV-C light disinfection, compared to the current disinfection method with the endoscope washer disinfector (EWD).

DESIGN, SETTING AND PARTICIPANTS

After pharyngolaryngoscopy, a manual pre-cleaning with tap water was performed. A culture was then collected by rolling the distal 8-10 cm of the FE over an Agar plate. The FE was disinfected using the D60 (60-s disinfection process with UV-C light) or the EWD (gold standard reprocessing process with water and chemicals). Another culture was then taken. After incubation, a CFU count was performed.

RESULTS

A total of 200 FEs without a working channel were divided equally between the two disinfection groups. After clinical use and manual pre-cleaning, 84 of the 100 (84.0%) (UV-C light group) and 79 of the 100 (79.0%) (EWD) FEs were contaminated with at least 1 CFU. FEs that showed no contamination after use were excluded from further analysis. After disinfection with UV-C light, 72 (85.7%) FEs showed no contamination (i.e., 0 CFUs) versus 66 (83.5%) FEs after reprocessing with the EWD.

CONCLUSION

There is no difference in CFUs reduction on contaminated FEs without a working channel between UV-C light disinfection and the current gold standard, the EWD.

Comparative Analysis of Super-Mini Percutaneous Nephrolithotomy Combined with Flexible Ureteroscopic Lithotripsy versus Flexible Ureteroscopic Lithotripsy Alone for Treating Complex Kidney Stones: A Retrospective Study of 205 Patients

BACKGROUND This retrospective study aimed to compare outcomes from super-mini percutaneous nephrolithotomy (SMP) combined with flexible ureteroscopic lithotripsy (FURL) and FURL alone in 205 patients with 2.5-4.2 cm diameter complex kidney stones. MATERIAL AND METHODS Between January 2018 and December 2022, 92 patients were treated with SMP combined with FURL (group A), and 113 patients were treated with FURL alone (group B). The stone-free rate (SFR), retreatment ratio, operation time, mean decline in hemoglobin level, postoperative pain visual analogue scale (VAS), and postoperative hospitalization time and complications were analyzed and compared between the 2 groups. RESULTS The SFR 3 days after the operation was 85.87% in group A, which was significantly higher than that in group B (72.57%) (P=0.021). The rate of retreatment in group A (3.26%) was significantly lower than that in group B (10.62%) (P=0.044). The SFR after 90 days was higher in group A (94.57%) than in group B (90.27%) (P=0.254). The mean decrease in hemoglobin, postoperative hospitalization duration, and VAS score 6 hours after the operation were all significantly higher in group A than in group B (P<0.05). However, there was no significant difference in operation time, VAS score at 12 and 24 hours after the operation, and complication rate. CONCLUSIONS In the treatment of complex renal stones, compared with FURL, SMP combined with FURL in the oblique supine lithotomy position has the advantages of a higher early SFR with no increased risk of complications.

Endoscopic or Microscopic Tympanoplasty Advantages and Disadvantages: A Theory Domain Systematic Review

Introduction  Tympanoplasty is a reparative surgery that has multiple indications. The aid of a microscope or an endoscope is necessary to carry out the procedure. The classic method utilizes the microscope; however, in the recent decades, the endoscope has been popular. Although many articles try to compare these two techniques, there is still no robust evidence that confirms the superiority of either technique. In the present work, we seek to perform a systematic review contribute with this. Objectives  The present systematic review attempted to compare endoscopic and microscopic surgery techniques and to discover whether there would be superiority in the results of any of them, based on data currently available in the literature. Data Synthesis  The objectives of the present review were organized according to the PICO planning and strategy adapted for systematic reviews. The inclusion and exclusion criteria were established aiming to select only select primary data. The main medical databases were searched using an optimized search string with appropriate descriptors. The searched databases were MEDLINE, LILACS, SciELO, and EMBASE. A total of 99 studies were selected and 38 were fully assessed after the inclusion criteria were applied. All included articles were reviewed by all authors and their results were discussed and summarized. Conclusion  The endoscopic technique was shown to be a safer technique comparable in effectiveness to the use of microscopy. In addition, it provides possible advantages such as shortening the surgical time and better postoperative pain outcomes.

Real time endobronchial ultrasound transbronchial needle aspiration for the diagnosis of tuberculous intrathoracic lymphadenopathy: Saudi Arabian Western region experience

OBJECTIVES

To assess the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for presumptive tuberculosis (TB) patients with intrathoracic enlarged lymph nodes in a country with low to moderate TB incidence.

METHODS

Thirty-one patients with clinical features of TB and intrathoracic lymphadenopathy, who had EBUS-TBNA sampling and final confirmation of intrathoracic TB lymphadenopathy, were retrospectively reviewed over an 8-year period. Routine clinical and laboratory evaluations including computerized tomography scans were performed before the EBUS-TBNA. Sociodemographic characteristics, clinical profile, pathological, and microbiological findings were collected.

RESULTS

The EBUS-TBNA confirmed TB diagnosis in 26 (83.9%) subjects with a consistent pathological finding or positive culture of Mycobacterium tuberculosis. Pathological analysis had findings consistent with TB in 25 (80.6%) patients. Culture of the EBUS-TBNA sample was positive for Mycobacterium tuberculosis in 12 (38.7%) patients. Other supportive investigations like purified protein derivative (PPD) skin test was positive in 28 (90.3%) participants. Overall, the sensitivity of the EBUS-TBNA alone was 83.9%. No complications were recorded during the procedure. The EBUS-TBNA aspirate culture positivity was significantly related to having a larger size lymph node (p=0.048) only, while PPD positivity was significantly related to baseline and clinical features of the participants.

CONCLUSION

The EBUS-TBNA demonstrated effective utility and safety in the evaluation and diagnosis of intrathoracic TB lymphadenopathy among individuals with compatible symptoms in a country with low-moderate TB-incidence.

Endoscopy-assisted versus open tissue expander placement in plastic and reconstructive surgery: a meta-analysis

Tissue expansion can be used to overcome challenges due to tissue deficiency in plastic and reconstructive surgery; however, the long expansion process is often accompanied by numerous complications. This meta-analysis aimed to determine whether endoscopy-assisted expander placement could decrease complications and shorten treatment time. This study followed the principles of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in PROSPERO (CRD42021226116). A literature search was performed in eight databases from their inception dates up to 25 August 2021, to identify clinical studies on endoscopy-assisted and/or open tissue expander placement in plastic and reconstructive surgery. Seven studies met the inclusion criteria. In seven studies, 194 underwent endoscopy-assisted expander placement, and 565 underwent open expander placement. The overall complication rate in the endoscopy-assisted group was significantly lower than that in the open group (risk difference (RD) -0.28, 95% confidence interval (CI), -0.38, -0.18, p < .001). Subgroup analysis showed significantly lower incidence rates of hematoma, infection and dehiscence in the endoscopy-assisted group. The complication rate in the head/neck was lower with low heterogeneity (RD, -0.18; 95% CI, -0.26 to -0.09, p < .001; I² = 0%). The endoscopy-assisted group had shorter surgery time, hospital stay and time to full expansion (weighted mean difference (WMD), -13.97 min, -16.88 h, -27.54 days; 95% CI, -15.85, -12.08 min, -24.36, -9.40 h, -38.85, -16.24 days; both p < .001, respectively). Endoscopy-assisted expander placement may help lower the risk of complications, especially in the head/neck, and reduce surgery time, hospital stay, and time to full expansion. Abbreviations: CI: confidence interval; CNKI: China National Knowledge Infrastructure Database; CSTJ, China Science and Technology Journal Database; NOS: the Newcastle-Ottawa Scale; PRISMA: preferred reporting items for systematic reviews and meta-analyses; RCT: randomized controlled trial; RoB: the cochrane risk-of-bias; RD: risk difference; WMD: weighted mean difference; SE: standard error; SND: standard normal deviate.

A 57-Year-Old Woman with Calcific Tendinitis of the Gluteus Medius Presenting with Right Lateral Hip Pain Managed by Endoscopic Debridement

BACKGROUND Calcific tendinitis of the hip is rare but most commonly occurs in the gluteus medius. It occurs more frequently in women, usually between the ages of 40 and 70 years. Calcific tendinitis of the gluteus medius is associated with pain and tenderness in the greater trochanter region, can be acute or chronic, and should be distinguished from other differential diagnoses, such as trochanteric bursitis. Calcific tendinitis of the gluteus medius is scarcely reported in the literature, and there is no management guideline for this condition. Although it is usually managed conservatively, there are reports of more invasive techniques, such as needle lavage and surgery. CASE REPORT We report the case of a middle-aged woman who presented with right hip pain of a 1-year duration, mainly on climbing stairs. Plain radiograph and magnetic resonance imaging revealed calcific tendinitis of the right gluteus medius. She underwent a trial of conservative management, which included a triamcinolone injection, but remained symptomatic. She subsequently underwent endoscopic debridement of the calcification and recovered uneventfully after surgery, with complete resolution of her symptoms at the 2-month follow-up. CONCLUSIONS This report has shown the importance of imaging in the diagnosis of calcific tendinitis of the gluteus medius and supports endoscopic debridement as an effective modality in the management of this condition.

Efficacy of chlorin dioxide wipes in disinfecting airway devices contaminated with Covid-19

Background

Reprocessing and disinfecting endoscopes is a routine practice in otolaryngology. An effective, safe, and rapid disinfection technique is essential during the COVID-19 pandemic.

Objective

To validate the efficacy of chlorine dioxide wipes in disinfecting three types of airway endoscopes contaminated with COVID-19-positive patient secretions.

Methods

Chlorine dioxide wipes were tested on rigid nasal endoscopes, laryngoscope blades, and flexible bronchoscopes. The endoscopes were disinfected using the wipes after exposure to COVID-19-positive patients. The tested scope was included in the study if the post procedure pre disinfection swab was positive for COVID-19 virus using RT-PCR. We analyzed 38 samples for 19 subjects (scopes) pre and post disinfection with chlorine dioxide wipes from July 2021 to February 2022.

Results

A total of four rigid endoscopes, four flexible bronchoscopes, and four laryngoscopes were included in the study which represent 24 pre and post disinfection swabs. The others were excluded because of negative pre disinfection swab. All the post disinfection PCR swab results were negative.

Conclusion

Chlorine dioxide is a convenient, fast, and effective disinfection technique for COVID-19-contaminated airway endoscopes.

A deep learning model using convolutional neural networks for caries detection and recognition with endoscopes

Background

Caries are common, especially in economically undeveloped countries with limited access to medical resources. Sometimes patient cannot even realize that they have oral problems until they feel obvious pain. Deep convolutional neural networks (CNNs) have been widely adopted for medical image analysis and management and have yielded some progress in stomatology while the endoscopes are cheap and easily used in daily life for families or other non-medical situations. Therefore, we created a deep learning model to detect and recognize caries using endoscopic images.

Methods

We used 194 images of non-caries and 1,059 images of permanent molar and premolar caries to build a classification and a segmentation model in patients of endoscope images from the Department of Stomatology of People's Liberation Army General Hospital (PLAGH). A classification model combined with an end-to-end semantic segmentation model, DeepLabv3+ was used for segmenting the caries, then we evaluated with a 5-fold cross-validation protocol whereby each fold was used once.

Results

In the classification model, the mean area under the curve (AUC) [90% confidence interval (CI)] was 0.9897 (0.9821-0.9956) (P<0.01) In the segmentation model, the mean accuracy was 0.9843 (0.9820-0.9871), the recall was 0.6996 (0.6810-0.7194), the specificity was 0.9943 (0.9937-0.9954), the Dice coefficient was 0.7099 (0.6948-0.7343), and the intersection over union (IoU) was 0.5779 (0.5646-0.6006).

Conclusions

We used a deep learning model to monitor caries and encourage their early diagnosis and treatment.

Feasibility of Laser Lithotripsy for Midsize Stones Using Robotic Retrograde Intrarenal Surgery System easyUretero in a Porcine Model

Purpose: To test the safety and feasibility of laser lithotripsy for midsize renal stones using a newly developed robotic retrograde intrarenal surgery (RIRS) system (easyUretero) in a porcine model. Materials and Methods: Three urologic surgeons representing three different RIRS experience levels (beginner, intermediate, and expert) participated. Four female pigs (aged 6 months) underwent manual or robotic RIRS. Under general anesthesia, a nephrostomy tract was created ventrally, and calcium stones (diameter, 1.0-1.5 cm) were inserted at renal calices. For manual RIRS, surgeons operated a flexible ureteroscope. For robotic RIRS, the ureteroscope was attached to the robotic slave device. The Auriga XL™ Holmium laser was used for lithotripsy. Lasering and stone retrieval time were measured. Kidneys and ureters were inspected for injury at the end of each session. Results: For the expert, both lasering and stone retrieval by manual RIRS were quicker than by robotic RIRS (22.8 ± 11.0 s/stone vs 234.5 ± 102.5 s/stone, p = 0.02; 41.5 ± 0.5 s/stone vs 79.3 ± 8.1 s/stone, p = 0.02). For the intermediate and beginner, lasering and stone retrieval times were not significantly different between manual and robotic procedures (127.8 ± 93.2 s/stone vs 284.8 ± 112.3 s/stone, p = 0.08; 86.0 ± 30.5 s/stone vs 84.1 ± 21.4 s/stone, p = 0.92). All stones were removed. Grade 1 ureteral and renal injuries occurred in both manual RIRS and robotic RIRS. Conclusions: The laser lithotripsy using the easyUretero robotic system is safe and feasible in a porcine model, even for less-experienced surgeons.

A Real-Time Endoscope Motion Tracker

OBJECTIVE

In colonoscopy, it is desirable to accurately localize the position of the endoscope's distal tip. Current tip localization techniques are not sufficient for recording the position and movement of the tip, nor is its rotation measured. We hypothesize that integration of multiple tracking modalities can effectively record the endoscope's motion in real time and continuously corrects cumulative errors.

METHODS

A dual modality tracking method is developed to measure the motion of the endoscope's insertion tube in real time, including insertion length, rotation angle, and their velocities. Optical trackballs were used to measure the endoscope insertion tube's motion and cameras were used to correct cumulative errors.

RESULTS

The accuracy of insertion length and rotational angle were measured. For speeds ≤ 10 mm/s, the median and 90th percentile insertion position errors were 0.88 mm and 2.2 mm, respectively. The insertion position error increases with the speed, reaching a maximum of 10 mm for speeds < 40 mm/s. 11° and 21° were the median and 90th percentile rotation angle errors for angular speeds < 40°/s. Cumulative errors are sufficiently reduced by the imaging modality.

CONCLUSION

The prototype device can precisely measure an unmodified endoscope's position, rotation, and motion in real time without significant accumulative error. The prototype device is small and compatible with existing commercial endoscopes as an add-on accessory, which could be used for reporting, localizing the lesions in follow up procedures, operational guidance, quality assurance, and training. Clinical and Translational Impact Statement-This preclinical research develops an endoscope tracker that can be integrated into colonoscopy training, automatically record endoscope motion, and be further developed to improve polyp and tumor localization during colonoscopy.

Active Stabilization of Interventional Tasks Utilizing a Magnetically Manipulated Endoscope

Magnetically actuated robots have become increasingly popular in medical endoscopy over the past decade. Despite the significant improvements in autonomy and control methods, progress within the field of medical magnetic endoscopes has mainly been in the domain of enhanced navigation. Interventional tasks such as biopsy, polyp removal, and clip placement are a major procedural component of endoscopy. Little advancement has been done in this area due to the problem of adequately controlling and stabilizing magnetically actuated endoscopes for interventional tasks. In the present paper we discuss a novel model-based Linear Parameter Varying (LPV) control approach to provide stability during interventional maneuvers. This method linearizes the non-linear dynamic interaction between the external actuation system and the endoscope in a set of equilibria, associated to different distances between the magnetic source and the endoscope, and computes different controllers for each equilibrium. This approach provides the global stability of the overall system and robustness against external disturbances. The performance of the LPV approach is compared to an intelligent teleoperation control method (based on a Proportional Integral Derivative (PID) controller), on the Magnetic Flexible Endoscope (MFE) platform. Four biopsies in different regions of the colon and at two different system equilibria are performed. Both controllers are asked to stabilize the endoscope in the presence of external disturbances (i.e. the introduction of the biopsy forceps through the working channel of the endoscope). The experiments, performed in a benchtop colon simulator, show a maximum reduction of the mean orientation error of the endoscope of 45.8% with the LPV control compared to the PID controller.

UV-C Light-Based Surface Disinfection: Analysis of Its Virucidal Efficacy Using a Bacteriophage Model

Background: The reprocessing of medical devices has become more complex due to increasing hygiene requirements. Previous studies showed satisfactory bactericidal disinfection effects of UV-C light in rigid and flexible endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of high importance. In the present study, the virucidal efficacy of UV-C light surface disinfection was analyzed. Methods: MS-2 bacteriophages were applied to the test samples and irradiated by UV-C light using the UV Smart D25 device; unirradiated test samples were used as controls. A dilution series of the samples was mixed with 1 × 108 Escherichia coli and assayed. Results: 8.6 × 1012 pfu could be harvested from the unprocessed test samples. In the control group without UV-C exposure, a remaining contamination of 1.2 × 1012 pfu was detected, resulting in a procedural baseline reduction rate with a LOG10 reduction factor of 0.72. The LOG10 reduction factor was found to be 3.0 after 25 s of UV-C light exposure. After 50 and 75 s of UV-C radiation LOG10 reduction factors 4.2 and 5.9, respectively, were found, with all reductions being statistically significantly different to baseline. Conclusions: The tested UV system seems to provide a significant virucidal effect after a relatively short irradiation time.

Is a small-caliber or large-caliber endoscope more suitable for colonic self-expandable metallic stent placement? A randomized controlled study

OBJECTIVES

The colonic self-expandable metallic stent (C-SEMS) with a 9-French (Fr) delivery system allows for a small-caliber endoscope (SCE) to be used to treat malignant colonic obstruction. Despite the lack of evidence, the SCE has become popular because it is considered easier to insert than the large-caliber endoscope (LCE). We aimed to determine whether the SCE is more suitable than the LCE for C-SEMS placement.

METHODS

Between July 2018 and November 2019, 50 consecutive patients who were scheduled to undergo C-SEMS for colon obstruction were recruited in this study. Patients were randomized to the SCE or LCE group. The SCE and LCE were used with 9-Fr and 10-Fr delivery systems, respectively. The primary outcome was the total procedure time. Secondary outcomes were the technical success rate, complication rate, clinical success rate, insertion time, guidewire-passage time, stent-deployment time, and colonic obstruction-scoring-system score.

RESULTS

Forty-five patients (SCE group, n = 22; LCE group, n = 23) were analyzed. The procedure time in the LCE group (median, 20.5 min) was significantly (p = 0.024) shorter than that in the SCE group (median, 25.1 min). The insertion time in the LCE group (median, 2.0 min) was significantly (p = 0.0049) shorter than that in the SCE group (median, 6.0 min). A sub-analysis of the procedure difficulties showed that the insertion time in the LCE group (median, 5.0 min) was significantly shorter than that in the SCE group (median, 8.5 min).

CONCLUSION

Both LCE and SCE can be used for C-SEMS; however, LCE is more suitable than SCE as it achieved a faster and equally efficacious C-SEMS placement as that of SCE.

CLINICAL TRIAL REGISTRATION NUMBER

University Hospital Medical Information Network Clinical Trials Registry (UMIN 32748).

Microbiological Surveillance of Endoscopes in a Southern Italian Transplantation Hospital: A Retrospective Study from 2016 to 2019

Endoscopes are medical instruments that are used routinely in health structures. Due to their invasive nature and contact with many patients, they may cause hospital-acquired infections if not disinfected correctly. To ensure a high-level disinfection procedure or reprocessing, since the methods currently adopted in our institute are adequate, we evaluated retrospectively the presence of microorganisms in our endoscopes after reprocessing. Microbiological surveillance was performed from January 2016 to December 2019 in the instruments in use in our endoscopic room after reprocessing. In total, 35 endoscopes (3 duodenoscopes, 3 echoendoscopes, 12 bronchoscopes, 5 colonoscopes, and 12 gastroscopes) were evaluated for the presence of microorganisms, including multidrug-resistant pathogens and indicator microorganisms (IMOs). Our procedures were in agreement with an internal protocol based on Italian, international, and the Center for Disease Control and Prevention (CDC) recommendations. Of a total of 811 samples, 799 (98.5%) complied with the regulatory guidelines, while 9 (1.1%) were positive for IMOs, and 3 (0.4%) displayed more than 10 colony-forming units (CFU) of environmental and commensal pathogens. Our results show that the internal reprocessing protocol is very efficient, leading to a very low number of observed contaminations, and it could be easily implemented by other health facilities that face a huge number of hospital-acquired infections due to incorrectly disinfected endoscopes.

A Review on Lossless Compression Techniques for Wireless Capsule Endoscopic Data

BACKGROUND

The videos produced during wireless capsule endoscopy have larger data size causing difficulty in transmission with limited bandwidth. The constraint on wireless capsule endoscopy hinders the performance of the compression module.

OBJECTIVES

The objectives of this paper are as follows: (i) to conduct an extensive review of the lossless compression techniques and (ii) to find out the limitations of the existing system and the possibilities for improvement.

METHODS

The literature review was conducted with a focus on the compression schemes satisfying minimum computational complexity, less power dissipation and low memory requirements for hardware implementation. A thorough study of various lossless compression techniques was conducted under two perspectives, i.e., techniques applied to Bayer CFA and RGB images. The detail of the various stages of wireless capsule endoscopy compression was investigated to have a better understanding. The suitable performance metrics for evaluating the compression techniques were listed from various literature studies.

RESULTS

In addition to the Gastrolab database, WEO clinical endoscopy atlas and Gastrointestinal atlas were found to be better alternatives for experimentation. Pre-processing operations, especially new subsampling patterns need to be given more focus to exploit the redundancies in the images. Investigations showed that encoder module can be modified to bring more improvement towards compression. The real-time endoscopy still exists as a promising area for exploration.

CONCLUSION

This review presents a research update on the details of wireless capsule endoscopy compression together with the findings as an eye-opener and guidance for further research.

Guidelines for Robotic Flexible Endoscopy at the Time of COVID-19

Flexible endoscopy involves the insertion of a long narrow flexible tube into the body for diagnostic and therapeutic procedures. In the gastrointestinal (GI) tract, flexible endoscopy plays a major role in cancer screening, surveillance, and treatment programs. As a result of gas insufflation during the procedure, both upper and lower GI endoscopy procedures have been classified as aerosol generating by the guidelines issued by the respective societies during the COVID-19 pandemic-although no quantifiable data on aerosol generation currently exists. Due to the risk of COVID-19 transmission to healthcare workers, most societies halted non-emergency and diagnostic procedures during the lockdown. The long-term implications of stoppage in cancer diagnoses and treatment is predicted to lead to a large increase in preventable deaths. Robotics may play a major role in this field by allowing healthcare operators to control the flexible endoscope from a safe distance and pave a path for protecting healthcare workers through minimizing the risk of virus transmission without reducing diagnostic and therapeutic capacities. This review focuses on the needs and challenges associated with the design of robotic flexible endoscopes for use during a pandemic. The authors propose that a few minor changes to existing platforms or considerations for platforms in development could lead to significant benefits for use during infection control scenarios.

[Endoscopic-assisted modified cricothyroid membrane approach for laryngeal surgery in patients with difficult airways]

Objective:To explore the value of endoscopic-assisted modified cricothyroid membrane approach laryngeal surgery in patients with difficult airways and evaluate its safety. Methods:All patients with laryngeal surgery who were hospitalized were evaluated. For the patients with difficult airways those could not be exposed through routine surgical approach, after full communication, we carried out the endoscope-assisted modified loop thyroscopic approach to the thyroid membrane. Results:All the 12 patients completed the operation successfully, and the visual field exposure was satisfactory during the operation. None of the patients had bleeding and glottic and subglottic stenosis after the operation, and the sound recovered satisfactorily. Conclusion:The cricothyroid membrane approach is not a routine choice for laryngeal surgery, but it is significantly better than other surgical methods for patients with difficult airways who are difficult to expose by conventional approaches, and it is a good choice for patients who cannot be exposed by conventional surgical approaches. The choice is worthy of clinical promotion.

Scanning and Actuation Techniques for Cantilever-Based Fiber Optic Endoscopic Scanners-A Review

Endoscopes are used routinely in modern medicine for in-vivo imaging of luminal organs. Technical advances in the micro-electro-mechanical system (MEMS) and optical fields have enabled the further miniaturization of endoscopes, resulting in the ability to image previously inaccessible small-caliber luminal organs, enabling the early detection of lesions and other abnormalities in these tissues. The development of scanning fiber endoscopes supports the fabrication of small cantilever-based imaging devices without compromising the image resolution. The size of an endoscope is highly dependent on the actuation and scanning method used to illuminate the target image area. Different actuation methods used in the design of small-sized cantilever-based endoscopes are reviewed in this paper along with their working principles, advantages and disadvantages, generated scanning patterns, and applications.

[Endoscope-assisted transoral resection of parapharyngeal space tumors: a retrospective study]

Objective:To evaluate the feasibility and safety of the endoscope-assisted transoral approach for the parapharyngeal space（PPS） tumors. Method:This retrospective study included 22 patients who were diagnosed with PPS tumors and treated with the endoscope-assisted transoral approach. Result:The postoperative pathological diagnosis included 10 cases of schwannoma, 7 cases of pleomorphic adenoma, 1 case of paraganglioma, 1 case of branchial cleft cyst, and 3 cases of malignant tumors for a diagnostic purpose. The surgical duration was between 15 minutes and 430 minutes（median duration 105 minutes）, and the intraoperative bleeding was between 10ml to 500ml（median bleeding 20 mL）. Complete resection with minor complication was performed in 21 cases, 1 case of recurrent schwannoma was done in an incomplete style because of intraoperative massive bleeding. With a 12-to-72-months follow up, there was no relapse on the 18 cases of benign tumor which were completely resected. Conclusion:Endoscope-assisted transoral resection provide cosmetic, micro-invasive and increased operative exposure to the PPS, especially for the benign tumors that medial to the carotid sheath. But is not recommend for relapsed cases and lesions that encompassing or lying posterolateral to the carotid sheath.

Establishing an Office-Based Framework for Resuming Otolaryngology Care in Academic Practice During the COVID-19 Pandemic

OBJECTIVE

The COVID-19 health crisis abruptly disrupted the practice of otolaryngology. This article aims to define the changes needed to operate an academic otolaryngology practice safely and efficiently from within the epicenter of the pandemic. We define the areas of normal patient workflow that have been affected by COVID-19, and we offer mitigation strategies with attention paid to the specific needs of subspecialties.

DATA SOURCES

The article includes data specific to the office practice metrics of the Weill Cornell Medicine Department of Otolaryngology-Head and Neck Surgery, as well as publically available data from New York Presbyterian Hospital system and the New York Times.

REVIEW METHODS

Expert opinion.

CONCLUSIONS

Through careful planning and execution, it is possible to reestablish safe otolaryngologic patient care during the COVID-19 pandemic. It will require a significant change from prior practice models for successful implementation. Additionally, telemedicine can be positively integrated into the treatment of otolaryngology diseases for new and established patients.

IMPLICATIONS FOR PRACTICE

The information conveyed in this review can be used as a guide by large and small otolaryngology groups to identify aspects of the patient visit that are "at risk" due to COVID-19, and it suggests sensible responses that can be made without a significant disruption to normal practice. The methods used to identify vulnerabilities with the patient visit process can be applied to future unforeseen crises, such as a resurgence of COVID-19 or a novel pandemic.

Unilateral Laminectomy by Endoscopy in Central Lumbar Canal Spinal Stenosis: Technical Note and Early Outcomes

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate the outcomes and safety of endoscopic laminectomy for central lumbar canal spinal stenosis.

SUMMARY OF BACKGROUND DATA

.: Spinal endoscopy is mostly used in the treatment of lumbar disc herniation, while endoscopic laminectomy for lumbar spinal stenosis is rarely reported.

METHODS

From January 2016 to June 2017, 38 patients with central lumbar canal spinal stenosis were treated with endoscopic laminectomy. Clinical symptoms were evaluated at 1, 3, 6, and 12 months and the last follow-up after surgery. Functional outcomes were assessed by using the Japanese Orthopedic Association Scores (JOA) and Oswestry Disability Index (ODI). The decompression effect was assessed by using the dural sac cross-sectional area (DSCA). Lumbar stability was evaluated using lumbar range of motion (ROM), ventral intervertebral space height (VH), and dorsal intervertebral space height (DH).

RESULTS

The mean age of the cases was 60.8 years, the mean operation time was 66.3 minutes, the blood loss was 38.8 mL, and the length of incision was 19.6 mm. The mean time in bed was 22.3 hours, and the mean hospital stay was 8.8 days. JOA scores were improved from 10.9 to 24.1 (P < 0.05), ODI scores were improved from 79.0 to 27.9 (P < 0.05), DSCA was improved from 55.7 to 109.5 mm (P < 0.05), ROM scores were improved from 5.6° to 5.7° (P < 0.05), and DH scores were reduced from 6.6 to 6.5 mm (P < 0.05). There was no significant difference in VH before and after operation (P > 0.05). There were no serious complications during the follow-ups.

CONCLUSION

Endoscopic laminectomy had the advantage of a wider view, which was effective, safe, and less invasive for lumbar spinal stenosis.

LEVEL OF EVIDENCE

5.

Isolated stridor without any other sleeping breathing disorder diagnosed using drug-induced sleep endoscopy in a patient with multiple system atrophy: A case report

RATIONALE

Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by Parkinsonism and autonomic dysfunction or cerebellar ataxia. MSA can be accompanied by stridor caused by laryngeal stenosis secondary to vocal cord dysfunction.

PATIENT CONCERN

A 60-year-old woman with MSA, complaining of difficulty in breathing during sleep. Her bed partner reported witnessing grunting-like sounds during sleep.

DIAGNOSIS

Isolated stridor without any other sleeping breathing disorder diagnosed using drug-induced sleep endoscopy (DISE) in a patient with MSA.

INTERVENTIONS

On polysomnography, there was no obstructive sleep apnea. Using DISE, abnormally adducted vocal cords during inspiratory respiration were identified, leading to a diagnosis of stridor. We prescribed positive airway pressure to resolve the stridor.

OUTCOME

Our patient was also prescribed continuous positive airway pressure for the treatment of nocturnal stridor, and it is improved.

LESSONS

In summary, when MSA patients present with nocturnal stridor, it is important to evaluate the exact diagnosis and cause of stridor in patients by confirming the movement of vocal cords using DISE, as well as polysomnography.

Learning colon centreline from optical colonoscopy, a new way to generate a map of the internal colon surface

Optical colonoscopy is known as a gold standard screening method in detecting and removing cancerous polyps. During this procedure, some polyps may be undetected due to their positions, not being covered by the camera or missed by the surgeon. In this Letter, the authors introduce a novel convolutional neural network (ConvNet) algorithm to map the internal colon surface to a 2D map (visibility map), which can be used to increase the awareness of clinicians about areas they might miss. This was achieved by leveraging a colonoscopy simulator to generate a dataset consisting of colonoscopy video frames and their corresponding colon centreline (CCL) points in 3D camera coordinates. A pair of video frames were used as input to a ConvNet, whereas the output was a point on the CCL and its direction vector. By knowing CCL for each frame and roughly modelling the colon as a cylinder, frames could be unrolled to build a visibility map. They validated their results using both simulated and real colonoscopy frames. Their results showed that using consecutive simulated frames to learn the CCL can be generalised to real colonoscopy video frames to generate a visibility map.

Needle-Guided Suture Technique for Lumbar Annular Fiber Closure in Microendoscopic Discectomy: A Technical Note and Case Series

BACKGROUND Annular fiber closure techniques have been proven effective in reducing short-term recurrence after discectomy. However, annular fiber closure devices are expensive and still fail at a low rate. We present a novel suture method, needle-guided annular closure suture (NGACS) that does not require a special device and can be performed for annular fiber closure following microendoscopic discectomy. MATERIAL AND METHODS Twenty-five patients who underwent treatment with NGACS were reviewed by analysis of the medical records. The clinical outcomes were assessed and compared preoperatively and immediately, 1, 6, and 12 months postoperatively. The parameters included the Visual Analog Scale (VAS)-back and VAS-leg scores and the Oswestry Disability Index (ODI). Midsagittal T2WI images were obtained to evaluate lumbar disc degeneration using the Pfirrmann grade. Additional adverse events were also recorded and tracked. RESULTS The VAS-back and VAS-leg scores and the ODI were significantly different at each follow-up time point (P<0.001), and improvements in pain and disability were maintained well during the follow-up period. Lumbar disc reherniation or other serious adverse events were not observed in this series. There was no significant difference between the initial and final Pfirrmann grades (Z=-1.414, P=0.157). The preoperative average disc height was 9.94±1.97 mm, and the disc height at 12 months after surgery was 9.14±1.88 mm. The average decrease in disc height was 8.11±3.36%. CONCLUSIONS This study demonstrates the feasibility and superior clinical outcomes of the NGACS technique. This method can be a good substitution when annular fiber closure devices are not available. Moreover, this technique can be easily popularized due to its low cost and few restrictions.

Enzymatic detergent reuse in gastroscope processing: a potential source of microorganism transmission

OBJECTIVE

to evaluate the potential contamination of enzymatic detergent from its reuse and to identify the microbiological profile in the solution used to clean gastrointestinal endoscopic devices.

METHOD

cross-sectional study based on microbiological analysis of 76 aliquots of 19 different enzymatic detergent solutions used to clean endoscopic devices. The aliquots were homogenized, subjected to Millipore® 0.45 µm membrane filtration and the presumptive identification of microorganisms was performed by biochemical-physiological methods according to previously established specific bacterial groups that are of clinical and epidemiological relevance.

RESULTS

the mean values, as well as the standard deviation and the median, of the enzymatic detergent microbial load increased as the solution was reused. There was a significant difference between the means of after first use and after fifth reuse. A total of 97 microorganisms were identified, with predominance of the coagulase-negative Staphylococcus, Pseudomonas spp., Klebsiella spp., Enterobacter spp. genus, and Escherichia coli species.

CONCLUSION

the reuse of the enzymatic detergent solution is a risk to the safe processing of endoscopic devices, evidenced by its contamination with pathogenic potential microorganisms, since the enzymatic detergent has no bactericidal property and can contribute as an important source for outbreaks in patients under such procedures.

Correlations between Aspiration and Pharyngeal Residue Scale Scores for Fiberoptic Endoscopic Evaluation and Videofluoroscopy

PURPOSE

To examine correlations among rating scales and findings suggestive of tracheal aspiration and pharyngeal residue between fiberoptic endoscopic evaluation of swallowing (FEES) and videofluoroscopic swallowing study (VFSS) in dysphagia patients.

MATERIALS AND METHODS

We studied patients referred to our hospital for dysphagia assessment. Three raters judged the residue severity and laryngeal penetration or tracheal aspiration of FEES and VFSS. The raters applied the Penetration-Aspiration Scale (PAS) for tracheal aspiration and pixel-based circumscribed area ratio and Yale Pharyngeal Residue Severity for post-swallow residue in VFSS and FEES, respectively. Anatomy-physiologic findings during FEES associated with tracheal aspiration were also analyzed.

RESULTS

A total of 178 participants were enrolled in our study. In correlation analysis, PAS (r=0.74), vallecula retention (r=0.76), and pyriform sinus retention (r=0.78) showed strong positive correlations between FEES and VFSS. Intra-rater agreement between VFSS and FEES was good for PAS (κ=0.65) and vallecula (κ=0.65) and pyriform sinus retention (κ=0.69). Among 72 patients who showed subglottic shelf residue, a suspected finding of aspiration, in FEES, 68 had concomitant tracheal aspiration during VFSS. Both vocal fold hypomobility and glottic gap during phonation were significantly associated with findings suggestive of tracheal aspiration during FEES (p<0.05).

CONCLUSION

Quantitative and reliable aspiration and post swallow residue rating scales showed strong positive correlations and good agreement between VFSS and FEES.

Automatic detection of calcium phosphate deposit plugs at the terminal ends of kidney tubules

Kidney stones are a common urologic condition with a high amount of recurrence. Recurrence depends on a multitude of factors the incidence of precursors to kidney stones, plugs, and plaques. One method of characterising the stone precursors is endoscopic assessment, though it is manual and time-consuming. Deep learning has become a popular technique for semantic segmentation because of the high accuracy that has been demonstrated. The present Letter examined the efficacy of deep learning to segment the renal papilla, plaque, and plugs. A U-Net model with ResNet-34 encoder was tested; the Letter examined dropout (to avoid overtraining) and two different loss functions (to address the class imbalance problem. The models were then trained in 1666 images and tested on 185 images. The Jaccard-cross-entropy loss function was more effective than the focal loss function. The model with the dropout rate 0.4 was found to be more effective due to its generalisability. The model was largely successful at delineating the papilla. The model was able to correctly detect the plaques and plugs; however, small plaques were challenging. Deep learning was found to be applicable for segmentation of an endoscopic image for the papilla, plaque, and plug, with room for improvement.

Endoscopic video defogging using luminance blending

Endoscopic video sequences provide surgeons with direct surgical field or visualisation on anatomical targets in the patient during robotic surgery. Unfortunately, these video images are unavoidably hazy or foggy to prevent surgeons from clear surgical vision due to typical surgical operations such as ablation and cauterisation during surgery. This Letter aims at removing fog or smoke on endoscopic video sequences to enhance and maintain a direct and clear visualisation of the operating field during robotic surgery. The authors propose a new luminance blending framework that integrates contrast enhancement with visibility restoration for foggy endoscopic video processing. The proposed method was validated on clinical endoscopic videos that were collected from robotic surgery. The experimental results demonstrate that their method provides a promising means to effectively remove fog or smoke on endoscopic video images. In particular, the visual quality of defogged endoscopic images was improved from 0.5088 to 0.6475.

Weakly supervised segmentation for real-time surgical tool tracking

Surgical tool tracking has a variety of applications in different surgical scenarios. Electromagnetic (EM) tracking can be utilised for tool tracking, but the accuracy is often limited by magnetic interference. Vision-based methods have also been suggested; however, tracking robustness is limited by specular reflection, occlusions, and blurriness observed in the endoscopic image. Recently, deep learning-based methods have shown competitive performance on segmentation and tracking of surgical tools. The main bottleneck of these methods lies in acquiring a sufficient amount of pixel-wise, annotated training data, which demands substantial labour costs. To tackle this issue, the authors propose a weakly supervised method for surgical tool segmentation and tracking based on hybrid sensor systems. They first generate semantic labellings using EM tracking and laparoscopic image processing concurrently. They then train a light-weight deep segmentation network to obtain a binary segmentation mask that enables tool tracking. To the authors' knowledge, the proposed method is the first to integrate EM tracking and laparoscopic image processing for generation of training labels. They demonstrate that their framework achieves accurate, automatic tool segmentation (i.e. without any manual labelling of the surgical tool to be tracked) and robust tool tracking in laparoscopic image sequences.

Stable polyp-scene classification via subsampling and residual learning from an imbalanced large dataset

This Letter presents a stable polyp-scene classification method with low false positive (FP) detection. Precise automated polyp detection during colonoscopies is essential for preventing colon-cancer deaths. There is, therefore, a demand for a computer-assisted diagnosis (CAD) system for colonoscopies to assist colonoscopists. A high-performance CAD system with spatiotemporal feature extraction via a three-dimensional convolutional neural network (3D CNN) with a limited dataset achieved about 80% detection accuracy in actual colonoscopic videos. Consequently, further improvement of a 3D CNN with larger training data is feasible. However, the ratio between polyp and non-polyp scenes is quite imbalanced in a large colonoscopic video dataset. This imbalance leads to unstable polyp detection. To circumvent this, the authors propose an efficient and balanced learning technique for deep residual learning. The authors’ method randomly selects a subset of non-polyp scenes whose number is the same number of still images of polyp scenes at the beginning of each epoch of learning. Furthermore, they introduce post-processing for stable polyp-scene classification. This post-processing reduces the FPs that occur in the practical application of polyp-scene classification. They evaluate several residual networks with a large polyp-detection dataset consisting of 1027 colonoscopic videos. In the scene-level evaluation, their proposed method achieves stable polyp-scene classification with 0.86 sensitivity and 0.97 specificity.

Upper gastrointestinal anatomy detection with multi-task convolutional neural networks

Esophagogastroduodenoscopy (EGD) has been widely applied for gastrointestinal (GI) examinations. However, there is a lack of mature technology to evaluate the quality of the EGD inspection process. In this Letter, the authors design a multi-task anatomy detection convolutional neural network (MT-AD-CNN) to evaluate the EGD inspection quality by combining the detection task of the upper digestive tract with ten anatomical structures and the classification task of informative video frames. The authors’ model is able to eliminate non-informative frames of the gastroscopic videos and detect the anatomies in real time. Specifically, a sub-branch is added to the detection network to classify NBI images, informative and non-informative images. By doing so, the detected box will be only displayed on the informative frames, which can reduce the false-positive rate. They can determine the video frames on which each anatomical location is effectively examined, so that they can analyse the diagnosis quality. Their method reaches the performance of 93.74% mean average precision for the detection task and 98.77% accuracy for the classification task. Their model can reflect the detailed circumstance of the gastroscopy examination process, which shows application potential in improving the quality of examinations.

Realistic endoscopic image generation method using virtual-to-real image-domain translation

A realistic image generation method for visualisation in endoscopic simulation systems is proposed in this study. Endoscopic diagnosis and treatment are performed in many hospitals. To reduce complications related to endoscope insertions, endoscopic simulation systems are used for training or rehearsal of endoscope insertions. However, current simulation systems generate non-realistic virtual endoscopic images. To improve the value of the simulation systems, improvement of the reality of their generated images is necessary. The authors propose a realistic image generation method for endoscopic simulation systems. Virtual endoscopic images are generated by using a volume rendering method from a CT volume of a patient. They improve the reality of the virtual endoscopic images using a virtual-to-real image-domain translation technique. The image-domain translator is implemented as a fully convolutional network (FCN). They train the FCN by minimising a cycle consistency loss function. The FCN is trained using unpaired virtual and real endoscopic images. To obtain high-quality image-domain translation results, they perform an image cleansing to the real endoscopic image set. They tested to use the shallow U-Net, U-Net, deep U-Net, and U-Net having residual units as the image-domain translator. The deep U-Net and U-Net having residual units generated quite realistic images.

Simultaneous shape and camera-projector parameter estimation for 3D endoscopic system using CNN-based grid-oneshot scan

For effective in situ endoscopic diagnosis and treatment, measurement of polyp sizes is important. For this purpose, 3D endoscopic systems have been researched. Among such systems, an active stereo technique, which projects a special pattern wherein each feature is coded, is a promising approach because of simplicity and high precision. However, previous works of this approach have problems. First, the quality of 3D reconstruction depended on the stabilities of feature extraction from the images captured by the endoscope camera. Second, due to the limited pattern projection area, the reconstructed region was relatively small. In this Letter, the authors propose a learning-based technique using convolutional neural networks to solve the first problem and an extended bundle adjustment technique, which integrates multiple shapes into a consistent single shape, to address the second. The effectiveness of the proposed techniques compared to previous techniques was evaluated experimentally.

Marker-less real-time intra-operative camera and hand-eye calibration procedure for surgical augmented reality

Accurate medical Augmented Reality (AR) rendering requires two calibrations, a camera intrinsic matrix estimation and a hand-eye transformation. We present a unified, practical, marker-less, real-time system to estimate both these transformations during surgery. For camera calibration we perform calibrations at multiple distances from the endoscope, pre-operatively, to parametrize the camera intrinsic matrix as a function of distance from the endoscope. Then, we retrieve the camera parameters intra-operatively by estimating the distance of the surgical site from the endoscope in less than 1 s. Unlike in prior work, our method does not require the endoscope to be taken out of the patient; for the hand-eye calibration, as opposed to conventional methods that require the identification of a marker, we make use of a rendered tool-tip in 3D. As the surgeon moves the instrument and observes the offset between the actual and the rendered tool-tip, they can select points of high visual error and manually bring the instrument tip to match the virtual rendered tool tip. To evaluate the hand-eye calibration, 5 subjects carried out the hand-eye calibration procedure on a da Vinci robot. Average Target Registration Error of approximately 7mm was achieved with just three data points.

Single use versus reusable digital flexible ureteroscopes: A prospective comparative study

OBJECTIVES

To compare the performance and surgical outcomes of two different single-use digital flexible ureteroscopes with a reusable video flexible ureteroscope.

METHODS

Patients undergoing retrograde flexible ureteroscopy at Nepean Hospital, Sydney, Australia, were included in this study. Three different flexible ureteroscopes were used in this study: (i) single-use digital LithoVue (Boston Scientific, Marlborough, MA, USA); (ii) single-use digital PU3022A (Pusen, Zhuhai, China); and (iii) reusable digital URF-V2 (Olympus, Tokyo, Japan). Visibility and maneuverability was rated on a 5-point Likert scale by the operating surgeon. Operative outcomes and complications were collected and analyzed.

RESULTS

A total of 150 patients were included in the present study. Of these, 141 patients had ureteroscopy for stone treatment, four for endoscopic combined intrarenal surgery and five for diagnostic/tumor treatment. There were 55 patients in the LithoVue group, 31 in the PU3022A group and 64 patients in the Olympus URF-V2 group. The URF-V2 group had higher visibility scores than both the single-use scopes and higher maneuverability scores when compared with the PU3022A. The LithoVue had higher visibility and maneuverability scores when compared with the PU3022A. There were no differences in operative time, rates of relook flexible ureteroscopes, scope failure or complication rates observed.

CONCLUSIONS

Single-use digital flexible ureteroscopes have visibility and maneuverability profiles approaching that of a reusable digital flexible ureteroscope. Single-use flexible ureteroscopes achieve similar clinical outcomes to the more expensive reusable versions.

A comparative randomized trial of intubation success in difficult intubation cases: the use of a Frova intubation catheter versus a Bonfils intubation fiberoscope

Introduction

A difficult airway is one of the main causes of morbidity and mortality in patients who undergo surgical interventions. Therefore, many devices and algorithms have been developed for the management of a difficult airway. However no study has been conducted comparing Frova catheter (FC) and a Bonfils fiberoscope (BF) to date.

Aim

To compare the effectiveness and success of two devices, a FC and BF, in difficult intubation cases.

Material and methods

Design: Single-centre randomized controlled trial in patients with difficult airways. The assignment order was created by unplanned number charts, and the assignment was hidden in closed covers, which were not unlocked until case permission had been provided. Setting: The trial was undertaken in a university hospital in Turkey. The primary analysis was based on 60 participants (n = 30, n = 30) with difficult intubation. The main outcomes were the success rates of placement of the tracheal tube in the trachea and the duration of the tracheal intubation process.

Results

In the BF group, successful intubation was carried out in 25 of the 30 (83.3%) patients, whereas intubation was successful in 28 of the 30 patients (93.3%) in the FC group. Patients who could not be intubated with the first device were intubated with the other device. The mean duration of intubation was 109 (85–140) s in the BF group, whereas it was 38.8 (26–60) s in the FC group.

Conclusions

Both devices were successful in difficult intubation cases. However, given the shorter duration of intubation using the FC and its lower cost as compared with that of the BF, the FC can be considered superior to the BF in difficult intubation cases.

A case of nasopharyngeal angiofibroma removed using a minimally invasive endoscopic endonasal technique

Nasopharyngeal angiofibroma is a rare head and neck tumor characterized by hypervascularity. With the development of various surgical devices and hemostatic agents, endoscopic endonasal surgery for nasopharyngeal angiofibroma, which is characterized by significant intraoperative bleeding, has become possible. We describe our experiences performing an effective endoscopic endonasal removal of a nasopharyngeal angiofibroma without embolization, using advanced devices and hemostatic agents. A 21-year-old male patient presented with massive epistaxis. The characteristic findings of angiofibroma were confirmed by computed tomography scan and nasal endoscopy. Navigation-guided endoscopic endonasal surgery was performed, and complementary devices and products were used to effectively remove the mass. Development of navigation, endoscopes, tissue handling devices, and hemostatic agents has enabled effective endoscopic endonasal removal of nasopharyngeal angiofibroma without embolization.

Integrative microendoscopic system combined with conventional microscope for live animal tissue imaging

Intravital optical imaging technology is essential for minimally invasive optical diagnosis and treatment in small animal disease models. High-resolution imaging requires high-resolution optical probes, and high-resolution optical imaging systems based on highly precise and advanced technologies and therefore, associated with high-system costs. Besides, in order to acquire small animal live images, special types of animal imaging setups are indispensable. In this paper, a microendoscopic system is designed as an add-on to existing conventional imaging microscopes, reducing the price of complete confocal endomicroscopic systems. The proposed attachable system can be configured for confocal microscopes from common manufacturers and this enables users to acquire live animal cellular images from a conventional system. It features a 4f optical plane relay system, a rotary stage for side-view endoscopic probes, and an endoscopic probe mount which swings between the horizontal and the vertical. The system could be widely useful for biological studies of animal physiology and disease models.

ARssist: augmented reality on a head-mounted display for the first assistant in robotic surgery

In robot-assisted laparoscopic surgery, the first assistant (FA) is responsible for tasks such as robot docking, passing necessary materials, manipulating hand-held instruments, and helping with trocar planning and placement. The performance of the FA is critical for the outcome of the surgery. The authors introduce ARssist, an augmented reality application based on an optical see-through head-mounted display, to help the FA perform these tasks. ARssist offers (i) real-time three-dimensional rendering of the robotic instruments, hand-held instruments, and endoscope based on a hybrid tracking scheme and (ii) real-time stereo endoscopy that is configurable to suit the FA's hand-eye coordination when operating based on endoscopy feedback. ARssist has the potential to help the FA perform his/her task more efficiently, and hence improve the outcome of robot-assisted laparoscopic surgeries.

Endoscopic image enhancement with noise suppression

Stereoscopic endoscopes have been used increasingly in minimally invasive surgery to visualise the organ surface and manipulate various surgical tools. However, insufficient and irregular light sources become major challenges for endoscopic surgery. Not only do these conditions hinder image processing algorithms, sometimes surgical tools are barely visible when operating within low-light regions. In addition, low-light regions have low signal-to-noise ratio and metrication artefacts due to quantisation errors. As a result, present image enhancement methods usually suffer from heavy noise amplification in low-light regions. In this Letter, the authors propose an effective method for endoscopic image enhancement by identifying different illumination regions and designing the enhancement design criteria for desired image quality. Compared with existing image enhancement methods, the proposed method is able to enhance the low-light region while preventing noise amplification during image enhancement process. The proposed method is tested with 200 images acquired by endoscopic surgeries. Computed results show that the proposed algorithm can outperform state-of-the-art algorithms for image enhancement, in terms of naturalness image quality evaluator and illumination index.