Flexible endoscopic instrument for diagnosis and treatment of early gastric cancer

Gastric cancer is a common cancer endangering human life and health worldwide. Early detection and diagnosis of gastric cancer that is normally performed by flexible endoscope can significantly improve the survival rate of patients. However, current endoscopic instruments have some problems, such as limitation of degrees of freedom (DOFs) and lack of surgical triangulation. Meanwhile, the lack of an intraoperative technique for the real-time evaluation of early gastric cancer is also a serious problem. To solve these problems, we have developed a dual-bending flexible endoscopic instrument for the diagnosis and treatment of early gastric cancer. This instrument has a compact structure with a maximum outer diameter of 3 mm and an insertion length of 1220 mm. It has 5 DOFs with a dual-bending function, which can form a surgical operation triangulation to easily perform the endoscopic procedure. Apart from the surgical forceps, the end of the instrument can be equipped with different endoscopic devices to meet the needs of diagnosis and treatment, such as endomicroscopic probes, electrosurgical knives, and laser ablation optical fibers. It is verified that the instrument can carry these devices to complete corresponding tasks, demonstrating the great potential of this instrument in clinical applications.

Soft Magnetostrictive Actuator String with Cellulose Nanofiber Skin

The formation of cellulose nanofibrous skin with a colloidal suspension is challenging due to the diffusion of colloidal particles and bacteria to the bulk and a limited supply of oxygen for bacteria in the liquid culture environment. A composite-actuating string was fabricated with magnetic nanoparticles (MNPs) and Gluconacetobacter xylinus in a solid matrix of hydrophobic microparticles. G. xylinus synthesizes a dense skin layer of cellulose nanofibers enclosing MNPs in the solid matrix to form an actuator string responsive to an external magnetic field. The nanofibrous actuator string is transformable to fit the diverse shapes of tubular structures in cross section due to its softness and plastic deformability, which reduce friction and stress against the walls of organ tissues. The nanofibrous skin string is bendable at an acute angle by magnetic actuation and is applicable as an endoscopic guidewire to reach a target deep inside a model kidney structure.

Compressive endoscopic imaging with complementary light modulation

We propose an effective endoscopic imaging method utilizing compressive sensing (CS) theory on the basis of complementary light modulation of a spatial light modulator. Both the simulated and the experimental results show that complementary compressive sensing (CCS) always needs less time to obtain better work than conventional CS with normal modulation at the same sampling rate. First, the speed of CCS is at least twice as fast as CS. Second, in comparison with CS, CCS can improve the signal-to-noise ratio of the reconstructed image by 49.7%, which indicates that this method is of great significance to endoscopic applications in terms of image fidelity and denoising performance.

Solution to prevent tumor spillage in minimally invasive radical hysterectomy using the endoscopic stapler for treating early-stage cervical cancer: Surgical technique with video

Gynecologic oncologists had originally preferred minimally invasive surgery (MIS) over laparotomic surgery for patients with early-stage cervical cancer until the Laparoscopic Approach to Cervical Cancer (LACC) trial reported a worse prognosis and more loco-regional recurrence in patients treated with MIS. Although some controversy remains, experts suggested that tumor cell spillage and aggravation may have been caused by intra-corporeal colpotomy, usage of uterine elevators, maintenance of Trendelenburg position, and tumor irritation by capnoperitoneum during surgery. Thus, we introduce a surgical procedure with some steps added to the conventional MIS radical hysterectomy for preventing tumor spillage during the surgery, which is currently being evaluated in terms of safety and efficacy through a prospective, multicenter, single-arm, phase II study, entitled "Safety of laparoscopic or robotic radical surgery using endoscopic stapler for inhibiting tumor spillage of cervical neoplasms (SOLUTION trial: NCT04370496)".

All-fiber probes for endoscopic optical coherence tomography of the large airways

Endoscopic optical coherence tomography of large airways poses unique challenges. A hybrid lens is described that consists of a section of coreless fiber and graded index fiber (GIF), followed by a ball lens section. This design produces low numerical aperture beams better suited for large airway imaging. The performance of this lens is compared against conventional GIF and ball lens designs. Forward- and side-viewing probes were modeled, fabricated, and tested. The impact of a sheath on the beam profile was also investigated. Probes with working distances larger than 10 mm and depth-of-focus exceeding 12 mm are demonstrated with the proposed design.

One-year clinical outcome after full-endoscopic interlaminar lumbar discectomy for isthmic lumbar spondylolisthesis: Two case reports

RATIONALE

For isthmic lumbar spondylolisthesis (ILS) associated with the removal of herniation, it remains challenging to perform less invasive and minimally disruptive procedures. Good results could potentially be obtained by further preserving the posterior elements in full-endoscopic lumbar discectomy (FESS), which is less invasive than microenscopic surgery (MES).

PATIENT CONCERNS

One patient complained of left leg pain, and another patient complained of right leg pain and low back pain.

DIAGNOSES

Two patients with ILS and Meyerding Grade 1 lumbar spondylolisthesis.

INTERVENTIONS

We performed a full-endoscopic lumbar discectomy via the interlaminar space (FESS-IL) for L5/S1 lumbar disc herniation (LDH) accompanied by isthmic lumbar spondylolisthesis. FESS-IL was performed in 2 patients with radiculopathy caused by different types of LDH using a full endoscopic system with a 4.1 mm working channel and 6.9 mm outer diameter. A 3.5-mm diameter high-speed drill was used in one patient for an upward-migrated LDH in the inner-rim of the infravertebral border. The other patient underwent minimal resection without bone resection.

OUTCOMES

The one-year clinical outcome included confirmation of pain relief and evacuation of migrated LDH on magnetic resonance imaging in all patients. There was no progression of slippage on radiography. The mean operative time was 82 min, and no complication was observed. The one-year clinical outcome demonstrated sufficient pain relief.

LESSONS THE Y

ear postoperative outcome showed improvement. We believe that FESS-IL is a viable alternative operative approach for LDH for ILS.

Total endoscopic sublay mesh repair for umbilical hernias

Umbilical hernias constitute some of the most common surgical diseases addressed by surgeons. Endoscopic techniques have become standard of care together with the conventional open techniques for the treatment of umbilical hernias. Several different approaches were described to achieve laparoscopic sublay repair.We prospectively collected and reviewed the medical records of 10 patients with umbilical hernias underwent total endoscopic sublay repair (TES) at our institution from November 2017 to November 2019. All operations were performed by a same surgical team. The demographics, intraoperative details, and postoperative complications were evaluated.All TES procedures were successfully performed without conversion to an open operation. No intraoperative morbidity was encountered. The average operative time was 109.5 minutes (range, 80-140 minutes). All the patients resumed an oral diet within 6 hours after the intervention. The mean time to ambulation was 7.5 hours (range, 4-14 hours), and mean postoperative hospital stay was 2.2 day (range, 1-4 days). One patient developed postoperative seroma. No wound complications, chronic pain, or recurrence were registered during the follow-up.Initial experiences with this technique show that the TES is a safe, and effective procedure for the treatment of umbilical hernias.

Injectable Thermogel Generated by the "Block Blend" Strategy as a Biomaterial for Endoscopic Submucosal Dissection

Endoscopic submucosal dissection is an established method for the removal of early cancers and large lesions from the gastrointestinal tract but is faced with the risk of perforation. To decrease this risk, a submucosal fluid cushion (SFC) is needed clinically by submucosal injection of saline and so on to lift and separate the lesion from the muscular layer. Some materials have been tried as the SFC so far with disadvantages. Here, we proposed a thermogel generated by the "block blend" strategy as an SFC. This system was composed of two amphiphilic block copolymers in water, so it was called a "block blend". We synthesized two non-thermogellable copolymers poly(d,l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) and blended them in water to achieve a sol-gel transition upon heating in both pure water and physiological saline. We explored the internal structure of the resultant thermogel with transmission electron microscopy, three-dimensional light scattering, ¹³C NMR, fluorescence resonance energy transfer, and rheological measurements, which indicated a percolated micelle network. The biosafety of the synthesized copolymer was preliminarily confirmed in vitro. The main necessary functions as an SFC, namely, injectability of a sol and the maintained mucosal elevation as a gel after injection, were verified ex vivo. This study has revealed the internal structure of the block blend thermogel and illustrated its potential application as a biomaterial. This work might be stimulating for investigations and applications of intelligent materials with both injectability and thermogellability of tunable phase-transition temperatures.

Quantification of Aerosol Concentrations During Endonasal Instrumentation in the Clinic Setting

OBJECTIVE

Recent anecdotal reports and cadaveric simulations have described aerosol generation during endonasal instrumentation, highlighting a possible risk for transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) during endoscopic endonasal instrumentation. This study aims to provide a greater understanding of particle generation and exposure risk during endoscopic endonasal instrumentation.

STUDY DESIGN

Prospective quantification of aerosol generation during office-based nasal endoscopy procedures.

METHODS

Using an optical particle sizer, airborne particles concentrations 0.3 to 10 microns in diameter, were measured during 30 nasal endoscopies in the clinic setting. Measurements were taken at time points throughout diagnostic and debridement endoscopies and compared to preprocedure and empty room particle concentrations.

RESULTS

No significant change in airborne particle concentrations was measured during diagnostic nasal endoscopies in patients without the need for debridement. However, significant increases in mean particle concentration compared to preprocedure levels were measured during cold instrumentation at 2,462 particles/foot3 (95% CI 837 to 4,088; P = .005) and during suction use at 2,973 particle/foot3 (95% CI 1,419 to 4,529; P = .001). In total, 99.2% of all measured particles were ≤1 μm in diameter.

CONCLUSION

When measured with an optical particle sizer, diagnostic nasal endoscopy with a rigid endoscope is not associated with increased particle aerosolization in patient for whom sinonasal debridement is not needed. In patients needing sinonasal debridement, endonasal cold and suction instrumentation were associated with increased particle aerosolization, with a trend observed during endoscope use prior to tissue manipulation. Endonasal debridement may potentially pose a higher risk for aerosolization and SARS-CoV-2 transmission. Appropriate personal protective equipment use and patient screening are recommended for all office-based endonasal procedures.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E1415-E1421, 2021.

A systematic review and meta-analysis of the safety and efficacy of remifentanil and dexmedetomidine for awake fiberoptic endoscope intubation

BACKGROUND

Awake fiberoptic endoscope intubation (AFOI) is the primary strategy for managing anticipated difficult airways. Adequate sedation, most commonly being achieved with remifentanil and dexmedetomidine, is integral to this procedure. This meta-analysis aimed to compare the safety and efficacy of these 2 sedatives.

METHODS

We conducted electronic searches in Embase, Web of Science, PubMed, Google Scholar, Medline, Springer, and Web of Science with no language restrictions. Studies comparing safety and efficacy between the sole use of remifentanil and dexmedetomidine among patients who underwent AFOI were included. Eight randomized controlled trials, comprising 412 patients, met the inclusion criteria. The primary outcomes were first attempt intubation success rate and incidence of hypoxia. The secondary outcomes were the Ramsay Sedation Scale score at intubation, memory recall of endoscopy, and unstable hemodynamic parameters during intubation.

RESULTS

Dexmedetomidine significantly reduced the incidence of hypoxemia during AFOI (risk ratio: 2.47; 95% confidence [CI]: 1.32-4.64]) compared with remifentanil; however, the first intubation success rates were equivalent (risk ratio: 1.12; 95% CI: 0.87-1.46]. No significant differences between the 2 sedatives were found for the Ramsay Sedation Scale score at intubation (mean difference: -0.14; 95% CI: -0.66-0.38) or unstable hemodynamic parameters during intubation (risk ratio: 0.83; 95% CI: 0.59-1.17). Dexmedetomidine reduced memory recall of endoscopy (risk ratio: 1.39; 95% CI: 1.13-1.72).

CONCLUSIONS

While both remifentanil and dexmedetomidine are effective for AFOI and well-tolerated, dexmedetomidine may be more effective in reducing the incidence of hypoxemia and memory recall of endoscopy.

PROSPERP REGISTRATION NUMBER

CRD42020169612.

Endoscopic Endonasal Resection of a Pontine Brainstem Cavernoma

Surgical treatment of brainstem cavernoma is controversial.¹ With modern surgical technique, safe and complete removal of selected brainstem cavernoma is possible.² The choice of optimal corridor must consider various factors, including eloquent structures of the brainstem, cavernoma shape and location, as well as the presence of an exophytic portion to the lesion.^3,4 The endoscopic endonasal approach, with its refinement through the last decade, could offer an optimal corridor for the removal of ventral brainstem cavernomas. This video exemplifies the key surgical steps, advantages of the technique, and relevant anatomy for the endoscopic endonasal removal of a ventrally exophytic pontine cavernoma.

The application of a 70° endoscope in performing transcanal middle ear surgery

BACKGROUND

Endoscopes increase the expediency of transcanal middle ear surgery. However, the application of a 70° endoscope is limited and seldom discussed, mainly because of its large angle. We introduce our experiences with the 70° endoscope in transcanal middle ear surgery.

METHODS

This is a retrospective chart review of 127 patients with chronic otitis media who underwent middle ear surgery performed by the senior author in 2016 at a tertiary referral center. The types of eardrum perforation were classified as central, inferior, posterior, or anterior according to the main location of the hole. The demographics, surgical pictures, and operative records were reviewed.

RESULTS

In 15 ears of the 127 patients, the ossicles were recognized directly by a microscope. In another 112 ears, the ossicles could not be identified under a microscope. Without elevating the tympanomeatal flap, the ossicles could be recognized in 72 of these 112 ears with endoscopes, especially the 70° endoscope. In 35 of these 112 ears, an incision to extend the drum perforation or creation of a small tympanomeatal flap in the posterior-superior canal was made to observe the ossicles. However, 5 of these 112 ears were still noted to have a narrow and/or curved ear canal and preoperatively needed to undergo endaural incisions. Among the other 122 patients who first underwent attempted transcanal surgery, 15 ears changed to endaural incisions. The drum perforations were repaired directly through the perforation in 107 ears via the transcanal route. One year after surgery, the air-bone gap closure was 16.0 ± 11.8 dB, and the graft take rate was 91.3%.

CONCLUSION

With the help of a 70° endoscope, we can use the transcanal transperforation route to evaluate and reconstruct drum perforations and ossicular chains in appropriate patients. Hence, normal tissue injuries to the ear canal can be minimized.

Pivotal Study of a Novel Motor-Driven Endoscopic Ablation System

[Figure: see text].

Updates in techniques for improved visualization in sinus surgery

PURPOSE OF REVIEW

Adequate visualization during endoscopic sinus surgery (ESS) is one of the most critical aspects of performing well tolerated and successful surgery. The topic of visualization encompasses a broad spectrum of preoperative and intraoperative manoeuvres the surgeon can perform that aid in the understanding of the patient's anatomy and in the delivery of efficient surgical care.

RECENT FINDINGS

Preoperative considerations to improve visualization include optimization of haemostasis through management of comorbidities (e.g. hypertension, coagulopathies), medication management (e.g. blood thinners) and systemic versus topical corticosteroids. New technologies allow preoperative visual mapping of surgical plans. Advances in knowledge of intraoperative anaesthesia have encouraged a move toward noninhaled anaesthetics to reduce bleeding. High definition cameras, angled endoscopes, 3D endoscopes and more recently augmented reality, image-guided surgery, and robotic surgery, represent the state of the art for high-quality visualization. Topical interventions, such as epinephrine, tranexamic acid and warm isotonic saline, can help to reduce bleeding and improve the operative field. Surgical manoeuvres, such as polyp debulking, septoplasty, carefully controlled tissue manipulation and a consistent repeatable approach remain fundamental to appropriate intraoperative surgical visualization.

SUMMARY

This chapter delineates medical, technical and technological means - preoperatively and intraoperatively - to achieve optimized visualization of the surgical field in ESS.

How close are we to anterior robotic skull base surgery?

PURPOSE OF REVIEW

The application of robotic surgery to anterior skull base disease has yet to be defined despite the potential for improved tumour resection with less morbidity in this region. Complex anatomy and restricted access have limited the development of robotic anterior skull base surgery.

RECENT FINDINGS

A limited number of transoral robotic surgical anterior skull base procedures have been undertaken; however, there are significant limitations to the utilization of this technology in the anterior skull base. In this article, the advantages, disadvantages and limitations of robotic anterior skull base surgery are discussed. Currently, the major limitation is the size of the robotic endoscope and of the available instrumentation. Technological advancements that provide promise for the future development of robotic anterior skull base surgery are in development, such as single-port robots, flexible instrument systems and miniaturization and growth of minimally invasive platforms.

SUMMARY

Although transnasal access to the skull base is not possible with the currently available robotic systems, promising technology does exist and is in development. Robotic anterior skull base surgery promises to provide greater access to skull base disease, improve oncologic results, reduce morbidity and to reduce the ergonomic burden on the surgeon.

A Method Based on 3D Shape Analysis Towards the Design of Flexible Instruments for Endoscopic Maxillary Sinus Surgery

The emergence of steerable flexible instruments has widened the uptake of minimally invasive surgical techniques. In sinus surgery, such flexible instruments could enable the access to difficult-to-reach anatomical areas. However, design-oriented metrics, essential for the development of steerable flexible instruments for maxillary sinus surgery, are still lacking. This paper proposes a method to process measurements and provides the instrument designer with essential information to develop adapted flexible instruments for limited access surgery. This method was applied to maxillary sinus surgery and showed that an instrument with a diameter smaller than 2.4 mm can be used on more than 72.5% of the subjects' set. Based on the statistical analysis and provided that this flexible instrument can bend up to [Formula: see text] it is estimated that all areas within the maxillary sinus could be reached through a regular antrostomy without resorting to extra incision or tissue removal in 94.9% of the population set. The presented method was partially validated by conducting cadaver experiments.

Comparative study of endoscopic and microscopic tympanoplasty performed by a single experienced surgeon

PURPOSE

The use of endoscopes in otologic procedures has been increasing worldwide. This study aimed to compare the efficacy of microscopic tympanoplasty (MT) and endoscopic tympanoplasty (ET) for tympanic membrane and middle ear surgery.

MATERIALS AND METHODS

We retrospectively analyzed 81 patients who underwent MT (n = 44) and ET (n = 37) for chronic otitis media with tympanic membrane perforation performed by a single surgeon between January 2013 and September 2019. The hearing outcomes, graft success rate, complications, operation time and hospital stay, and cost-effectiveness were recorded and compared between groups. Hearing outcomes were determined by pure tone audiometry. Cost-effectiveness was determined by the operation cost and total cost.

RESULTS

There was no significant difference between the MT and ET groups regarding demographic characteristics, with the exception of the male:female ratio. There was no significant difference in the pre- and postoperative air conduction, bone conduction thresholds, and air-bone gap values between the two groups, but a significant audiologic improvement was observed in both groups (p < 0.05). In terms of recurrence of tympanic membrane perforation, postoperative otorrhea, and discomfort symptoms, there was no significant difference between groups (p > 0.05). The operation time and hospital stay were shorter in the ET group than in the MT group (p < 0.05). There were no significant differences in operation cost between the two groups (p > 0.05), but the total cost was significantly lower in the ET group than the MT group (p < 0.05).

CONCLUSION

ET is as safe and medically efficacious as conventional MT, shortens the operation time and hospital stay, and is cost-effective.

Does Robot Navigation and Intraoperative Computed Tomography Guidance Help with Percutaneous Endoscopic Lumbar Discectomy? A Match-Paired Study

OBJECTIVE

To evaluate the efficacy and safety of robot-assisted percutaneous endoscopic lumbar discectomy (rPELD) using a specially designed orthopaedic robot with an intraoperative computed tomography-equipped suite for treatment of symptomatic lumbar disc herniation and compare rPELD with fluoroscopy-assisted percutaneous endoscopic lumbar discectomy (fPELD).

METHODS

We retrospectively reviewed and compared demographic data, radiologic workups, and patient-reported outcomes of 39 patients treated with rPELD and 78 patients treated with fPELD at our institution between January 2019 and December 2019.

RESULTS

Our data showed that a single-shot puncture in the rPELD group was significantly more precise compared with 4.12 ± 1.71 trials in the fPELD group (P < 0.001). There was an overall reduction of fluoroscopy (21.33 ± 3.89 times vs. 33.06 ± 2.92 times, P < 0.001), puncture-channel time (13.34 ± 3.03 minutes vs. 15.03 ± 4.5 minutes, P = 0.038), and total operative time (57.46 ± 7.49 minutes vs. 69.40 ± 12.59 minutes, P < 0.001) using the rPELD technique versus the fPELD technique. However, there were no significant differences in patient-reported outcomes, length of hospital stay, and complication rate between the 2 groups (P > 0.05).

CONCLUSIONS

Taken together, our data indicate that rPELD provides a precise skin entry point and optimal trajectory for puncture, which increases the success rate of PELD, negating the need for revision surgery. However, further studies are required to confirm the superiority and application of the rPELD technique.

In Vivo Evaluation of a Miniaturized Fluorescence Molecular Tomography (FMT) Endoscope for Breast Cancer Detection Using Targeted Nanoprobes

In this study, in vivo animal experiments with 12 nude mice bearing breast-cancer-patient-tissue-derived xenograft (PDX) tumors were performed aiming to verify the imaging capability of a novel miniaturized fluorescence molecular tomography (FMT) endoscope, in combination with targeted nanoparticle–near-infrared (NIR) dye conjugates. Tumor-bearing mice were divided into two groups by systematic injection with urokinase plasminogen activator receptor-targeted (n = 7) and nontargeted (n = 5) imaging nanoprobes as a contrast agent, respectively. Each mouse was imaged at 6, 24, and 48 h following the injection of nanoprobes using the FMT endoscope. The results show that systemic delivery of targeted nanoprobes produced a 4-fold enhancement in fluorescence signals from tumors, compared with tumors that received nontargeted nanoprobes. This study indicates that our miniaturized FMT endoscope, coupled with the targeted nanoparticle–NIR dye conjugates as a contrast agent, has high sensitivity and specificity, and thus great potential to be used for image-guided detection and removal of a primary tumor and local metastatic tumors during surgery.

An Accelerated Finite-Time Convergent Neural Network for Visual Servoing of a Flexible Surgical Endoscope With Physical and RCM Constraints

This article designs and analyzes a recurrent neural network (RNN) for the visual servoing of a flexible surgical endoscope. The flexible surgical endoscope is based on a commercially available UR5 robot with a flexible endoscope attached as an end-effector. Most of the existing visual servo control frameworks of the robotic endoscopes or robot arms have not considered either the physical limits of the robot or the remote center of motion (RCM) constraints (i.e., the fulcrum effect). To tackle this issue, this article first conducts the kinematic modeling of the flexible robotic endoscope to achieve automation by visual servo control. The kinematic modeling results in a quadratic programming (QP) framework with physical limits and RCM constraints involved, making the UR5 robot applicable to surgical field. To solve the QP problem and accomplish the visual task, an RNN activated by a sign-bi-power activation function (AF) is proposed. The motivation of using the sign-bi-power AF is to enable the RNN to exhibit an accelerated finite-time convergence, which is more preferred in time-critical applications. Theoretically, the finite-time convergence of the RNN is rigorously proved using the Lyapunov theory. Compared with the previous AFs applied to the RNN, theoretical analysis shows that the RNN activated by the sign-bi-power AF delivers an accelerated convergence speed. Comparative validations are performed, showing that the proposed finite-time convergent neural network is effective to achieve visual servoing of the flexible endoscope with physical limits and RCM constraints handled simultaneously.

Early Career Challenges in Setting Up an Endoscopic Spine Surgery Practice

After the completion of an endoscopic spinal surgery fellowship, the next challenge for the newly minted consultant is to set up a viable and sustainable endoscopic practice. A successful practice of endoscopic spine surgery is dependent on several factors, such as anesthetic support; surgical expertise; support for provision and maintenance of endoscopic equipment; cost of equipment; administrative and nursing support; postoperative care services to optimize patients' outcome and satisfaction; patients' ideas, concerns, and expectations, as well as continuing medical education. In this article, a perspective is given on the early career challenges that a fellowship-trained endoscopic surgeon may encounter in the period leading to first successful endoscopic spinal surgery.

Introduction to Transmission of Infection: Potential Agents Transmitted by Endoscopy

Pathogen contamination of endoscopes depends on pathogen factors, surface factors, and environmental conditions. The most common pathogens associated with transmission and infections associated with gastrointestinal endoscope contamination are Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa. Biofilm production together with disruption to device surfaces play an outsized role in the risk of contamination. Sampling schemes are limited by these factors, and further developments are needed to improve the accuracy of sampling.

[En bloc MoLEP (MOSES HoLEP) with early apical dissection and preservation of the sphincter's mucosa. Surgical technique and technology developments that allow a new paradigm of endoscopic prostate enucleation]

Endoscopic enucleation of the prostate was first described by Hiraoka in 1986, using a monopolar resectoscope. His contribution was largely ignored until Gilling and Fraundorfer published their three-lobe enucleation technique with the Holmium laser in 1998 ,that ended establishing itself as a reliable option for the treatment of HBP, backed by ample scientific evidence. Later on, enucleation performed with other lasers, as well as bipolar energy, have shown concordance in their clinical results. As a result, the term AEEP (anatomic endoscopic enucleation of the prostate) emerged to encompass all these techniques. During the last few years there have been significant advances in two areas: first, technology, with the development of pulse modulation for Holmium generators (MOSES) as well as high-speed morcellators. Second, the development of new surgical techniques that recognize the importance of the early release of the sphincter from the apex of the adenoma during the operation as well as the careful preservation of the external sphincter's mucosa, to avoid early stress incontinence. In this paper,we review the recent evolution of both technology and surgical technique. AEEP has been risen to a new level, reducing operative time significantly, usually under one hour, and radically reducing the incidence of early temporary stress incontinence, and maybe also facilitating the learning curve of AEEP.

Handling of endoscopic equipment after use in the case of a patient with suspected prion disease

INTRODUCTION

Prion diseases are slow-acting, neurodegenerative diseases found in humans and many species of animals. Although they occur very rarely in humans, currently, an increase in this type of disease is being observed, probably as a result of exposure to infectious prions causing BSE disease in cows.

OBJECTIVE

The aim of the procedures described in the article is to minimize the risk of human-to-human transfer of all forms of transmissible spongiform encephalopathy, including variant CJD (vCJD) by contaminated medical equipment.

BRIEF DESCRIPTION OF THE STATE OF KNOWLEDGE

All diseases caused by prions, referred to as transmissible spongiform encephalopathies, are fatal. They are characterized by a long development period (up to several decades). Enormous problems are connected with the risk of transferring prions from patient to patient on the surface of instruments used in medical procedures. Laboratory tests indicate that standard disinfection and sterilization procedures may be insufficient to completely remove infectious proteins from contaminated instruments. One of the methods of infection prevention involves taking equipment used for surgery within the brain, tonsils or appendix, into quarantine until biopsy results of these organs have been received that exclude, as far as possible, asymptomatic carriage of prions.

CONCLUSIONS

Whenever possible and justified, disposable-use instruments should be used for invasive surgery in patients with definite, clinically probable cases of CJD (vCJD). After use, these instruments should be incinerated.

The usefulness and utilization of a detachable steel wire-rimmed retractor (KN retractor) for endoscopic thyroid and parathyroid surgery

PURPOSE

In endoscopic surgery, surgeons occasionally encounter difficulties due to visual field obstruction by muscles or blood vessels. In these situations, specialized instruments that can effectively retract these obstructions are required. Recently, we developed a new detachable wire-rimmed retractor (KN retractor) for narrow-space surgery.

METHODS

We evaluated the utility of this KN retractor in 15 patients with thyroid and parathyroid disease. Of those, five patients with papillary thyroid cancer had gasless endoscopic hemithyroidectomy with central node dissection, five underwent endoscopic total thyroidectomy for Graves' disease, and the remaining five received endoscopic parathyroidectomy with gas insufflation.

RESULTS

Surgeons were able to perform meticulous operations in a satisfactory visual field supported by the KN retractor. In all patients, the strap muscles were preserved without cutting. The average operating time was 149, 154, and 81 min in patients who underwent hemithyroidectomy with central node dissection, total thyroidectomy, and parathyroidectomy, respectively. Gas insufflation was successfully completed in all cases while maintaining sufficient airtightness.

CONCLUSIONS

The KN retractor is suitable for both the gasless lifting method and gas insufflation surgery in a narrow space. We believe that the KN retractor is a new device that will greatly improve the safety and shorten the operation time in endoscopic surgery.

Astigmatism-corrected endoscopic imaging probe for optical coherence tomography using soft lithography

In endoscopic optical coherence tomography, a transparent protective sheath is used to protect the optics and tissue. However, the sheath causes astigmatism, which degrades transverse resolution and signal-to-noise ratio due to the cylindrical lens effect. Generally used methods for correcting this astigmatism are complex, difficult to control precisely, high-cost, and increase the dimensions of the imaging probe. To overcome these problems, we have developed an astigmatism-corrected imaging probe with an epoxy window. The astigmatism is precisely and cost-effectively adjusted controlling the curvature radius of the epoxy window, which is produced by soft lithography. Using the fiber optic fusion splicing, the fabrication process is simple. The fabricated imaging probe is almost monolithic, so its diameter is similar to that of a standard single-mode fiber. We demonstrate its astigmatism-correcting performance using focal spot analysis, imaging micro-beads and a biological sample.

Nerve Segmentation with Deep Learning from Label-Free Endoscopic Images Obtained Using Coherent Anti-Stokes Raman Scattering

Semantic segmentation with deep learning to extract nerves from label-free endoscopic images obtained using coherent anti-Stokes Raman scattering (CARS) for nerve-sparing surgery is described. We developed a CARS rigid endoscope in order to identify the exact location of peripheral nerves in surgery. Myelinated nerves are visualized with a CARS lipid signal in a label-free manner. Because the lipid distribution includes other tissues as well as nerves, nerve segmentation is required to achieve nerve-sparing surgery. We propose using U-Net with a VGG16 encoder as a deep learning model and pre-training with fluorescence images, which visualize the lipid distribution similar to CARS images, before fine-tuning with a small dataset of CARS endoscopy images. For nerve segmentation, we used 24 CARS and 1,818 fluorescence nerve images of three rabbit prostates. We achieved label-free nerve segmentation with a mean accuracy of 0.962 and an F1 value of 0.860. Pre-training on fluorescence images significantly improved the performance of nerve segmentation in terms of the mean accuracy and F1 value (p<0.05). Nerve segmentation of label-free endoscopic images will allow for safer endoscopic surgery, while reducing dysfunction and improving prognosis after surgery.

Alternative uses of lumen apposing metal stents

The advent of lumen apposing metal stents (LAMS) has revolutionized the management of many complex gastroenterological conditions that previously required surgical or radiological interventions. These procedures have garnered popularity due to their minimally invasive nature, higher technical and clinical success rate and lower rate of adverse events. By virtue of their unique design, LAMS provide more efficient drainage, serve as conduit for endoscopic access, are associated with lower rates of leakage and are easy to be removed. Initially used for drainage of pancreatic fluid collections, the use of LAMS has been extended to gallbladder and biliary drainage, treatment of luminal strictures, creation of gastrointestinal fistulae, pancreaticobiliary drainage, improved access for surgically altered anatomy, and drainage of intra-abdominal and pelvic abscesses as well as post-surgical fluid collections. As new indications of endosonographic techniques and LAMS continue to evolve, this review summarizes the current role of LAMS in the management of these various complex conditions and also highlights clinical pearls to guide successful placement of LAMS.

The daily impact of COVID-19 in gastroenterology

A new strain of coronavirus, called SARS-CoV-2, emerged in Wuhan, China, in December 2019, probably originating from a wild-animal contamination. Since then, the situation rapidly evolved from a cluster of patients with pneumonia, to a regional epidemic and now to a pandemic called COrona VIrus Disease 2019 (COVID-19). This evolution is related to the peculiar modes of transmission of the disease and to the globalization and lifestyle of the 21st century that created the perfect scenario for virus spread. Even though research has not evidenced particular susceptibility of inflammatory bowel disease (IBD) patients to SARS-CoV-2 infection, immunosuppressive and immunomodulatory treatments were considered potential risk factors. In this context, initiating treatments with these agents should be cautiously weighted and regular ongoing treatments shall be continued, while the dose of corticosteroids should be reduced whenever possible. Due to the increased risk of contamination, elective endoscopic procedures and surgeries should be postponed and IBD online appointments shall be considered. IBD patients shall also follow the recommendations provided to the general population, such as minimization of contact with infected or suspected patients and to wash hands frequently. In the absence of effective treatments and vaccines, this pandemic can only be controlled through prevention of SARS-CoV-2 transmission with the main objectives of providing patients the best healthcare possible and reduce mortality.

[Clinical application value of the endoscopic surveillance system in transurethral bipolar plasmakinetic resection of the prostate]

OBJECTIVE

To evaluate the clinical application of the endoscopic surveillance system (ESS) in transurethral bipolar plasmakinetic resection of the prostate (TUPKRP).

METHODS

We retrospectively analyzed 136 cases of TUPKRP performed with the assistance of ESS from September 2018 to March 2019. According to the prostate volume (PV), we divided the patients into a PV ≥ 60 ml and a PV < 60 ml group, and compared the surgery-related parameters between the two groups of patients.

RESULTS

Operations were successfully completed in all the 136 cases. Statistically significant differences were observed between the PV ≥ 60 ml and a PV < 60 ml groups in the operation time (［78.93 ± 28.63］ vs ［51.77 ± 14.85］ min, P < 0.05), intraoperative blood loss (［261.61 ± 204.25］ vs ［69.26 ± 61.13］ ml, P < 0.05) and absorption of the rinse fluid (［948.20 ± 656.00］ vs ［347.39 ± 256.53］ ml, P < 0.05), but not in the postoperative red cell count, levels of hemoglobin, hematocrit and ions, hospital stay, incidence of prostatic perforation or blood transfusion (P > 0.05). The patients also showed statistically significant differences between the baseline and postoperative parameters in red cell count (［4.62 ± 0.63］ vs ［4.31 ± 0.74］ ×1012/L, P < 0.05) and levels of hemoglobin (［141.83 ± 18.30］ vs ［135.20 ± 19.91］ g/L, P < 0.05), K+ (［4.01 ± 0.43］ vs ［3.92 ± 0.54］ mmol/L, P < 0.05) and Na+ (［141.90 ± 3.11］ vs ［139.42 ± 3.81］ mmol/L, P < 0.05), but not in the levels of Cl－ (［103.74 ± 9.32］ vs ［103.70 ± 4.50］ mmol/L, P > 0.05) and Ca2+ (［2.21 ± 0.13］ vs ［2.19 ± 0.21］ mmol/L, P > 0.05).

CONCLUSIONS

Large-volume absorption of rinse fluid may overburden the circulatory system and induce left ventricular failure, pulmonary edema or massive bleeding during PKRP for patients with PV ≥ 60 ml due to long operation time and rich blood supply in the hyperplasia gland. The endoscopic surveillance system can provide real-time data on the absorption of rinse fluid and bleeding, reduce complications, and improve surgical safety.

Miniaturized precalibration-based Lissajous scanning fiber probe for high speed endoscopic optical coherence tomography

We present a miniaturized precalibration-based forward-viewing Lissajous scanning fiber probe for high speed endoscopic optical coherence tomography (OCT). The probe is based on an asymmetric fiber cantilever driven by the piezoelectric bender to realize two-dimensional (2D) Lissajous scanning. The stability and repeatability of the Lissajous scanning trajectory of the probe is tested by a position sensitive detector (PSD)-based position calibration setup. The two orthogonal resonant frequencies of the cantilever are measured to be 167.2 and 121 Hz. A 25 µm focal spot is formed at the working distance of 5 mm by the graded-index (GRIN) lens, and the field of view of the imaging probe is around ${1.5}\;{\rm mm} \times {1.5}\;{\rm mm}$1.5mm×1.5mm. The probe is fully packaged in a hypodermic tube for endoscopic imaging. The total rigid length and outer diameter are 35 mm and 3.5 mm, respectively. The probe is incorporated in a 50 KHz swept source OCT system with the axial resolution of 14 µm, and its imaging performance is validated by the 2D en face and 3D volumetric OCT imaging of the phantom and the biological tissue.

Calf Reduction by Partial Resection of Gastrocnemius Using a Suction-Assisted Cartilage Shaver

BACKGROUND

Long-term aesthetic reduction of the legs in Asians is gaining increasing popularity among cosmetic patients. Current treatment options include botulinum toxin injection, radiofrequency, neurectomy, and total, subtotal, or partial muscle resection of the gastrocnemius. Partial resection using Kelly forceps was introduced in 2000. This article presents the use of a suction-assisted cartilage shaver to perform partial resection, describing the procedures and shaver modifications and evaluating its use.

METHODS

A retrospective review of 71 cases with a minimum 6-month follow-up (average, 36.5 months; range, 6 to 160 months) was performed. Twenty partial calf reductions were performed with a short shaver, 27 with a long shaver, and 24 with an endoscope-guided long shaver.

RESULTS

Mean reduction of calf circumference was 2 cm (range, -1 to 6 cm); the mean preoperative and postoperative calf circumferences were 35.8 cm and 33.8 cm, respectively. Mean tissue reduction per calf was 110 g (range, 25 to 300 g).Two patients developed larger calves after surgery, one because of weight gain and the other because of weight training. Complications included surface irregularity (n = 4, 5.6 percent), numbness over the lateral ankle or lateral foot (n = 9, 12.7 percent), hematoma clot requiring surgical evacuation (n = 11, 15.5 percent), prolonged seroma (n = 2, 2.8 percent), and left ankle plantar-flexion contracture due to tight, sustained postsurgery bandaging (n = 1, 1.5 percent). Scar-related complications were hyperpigmentation (n = 6, 8.5 percent), depressed scars (n = 5, 7 percent), and hypertrophic scars (n = 2, 2.8 percent).

CONCLUSIONS

Short, long, and endoscope-guided long suction-assisted cartilage shavers for partial resection of calf muscles can be used effectively to reduce the calf. Several mostly treatable complications were noted.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Continuum Robot With Follow-the-Leader Motion for Endoscopic Third Ventriculostomy and Tumor Biopsy

BACKGROUND

In a combined endoscopic third ventriculostomy (ETV) and endoscopic tumor biopsy (ETB) procedure, an optimal tool trajectory is mandatory to minimize trauma to surrounding cerebral tissue.

OBJECTIVE

This paper presents wire-driven multi-section robot with push-pull wire. The robot is tested to attain follow-the-leader (FTL) motion to place surgical instruments through narrow passages while minimizing the trauma to tissues.

METHODS

A wire-driven continuum robot with six sub-sections was developed and its kinematic model was proposed to achieve FTL motion. An accuracy test to assess the robot's ability to attain FTL motion along a set of elementary curved trajectory was performed. We also used hydrocephalus ventricular model created from human subject data to generate five ETV/ETB trajectories and conducted a study assessing the accuracy of the FTL motion along these clinically desirable trajectories.

RESULTS

In the test with elementary curved paths, the maximal deviation of the robot was increased from 0.47 mm at 30 ° turn to 1.78 mm at 180 ° in a simple C-shaped curve. S-shaped FTL motion had lesser deviation ranging from 0.16 to 0.18 mm. In the phantom study, the greatest tip deviation was 1.45 mm, and the greatest path deviation was 1.23 mm.

CONCLUSION

We present the application of a continuum robot with FTL motion to perform a combined ETV/ETB procedure. The validation study using human subject data indicated that the accuracy of FTL motion is relatively high. The study indicated that FTL motion may be useful tool for combined ETV and ETB.

Endoscopic Full-thickness Resection with the Full-Thickness Resection Device (FTRD) for "difficult to resect" colonic lesions. A single-center experience

INTRODUCTION

Aim of our observational and retrospective study is to compare efficacy and indications of endoscopic full-thickness resection device (FTRD) with the over-the-scope (OVESCO) clip closure for en bloc resection of colorectal lesions (including adenomas, early carcinomas, inflammatory polyps and neuroendocrine tumors).

MATERIAL AND METHODS

This article collected 36 cases of colorectal neoplasms from a single Italian referral center per colorectal disease treatment. Primary endpoints included en bloc resection, R0 resection and an early discharge of the patient. Secondary endpoints included procedure-related adverse events.

RESULTS

Mean procedure time± standard deviation (SD) was 19.6±22.1 minutes and mean hospital stay (± SD) was 2.2±1.1 days. Overall, an en bloc resection was achieved in 34 cases (94.4%), with an R0 resection rate of 91.6%. Among the three not R0 patients, further additional treatments were needed.

DISCUSSION

Along the same line of other already published articles, the main current indications of EFTR by FTRD-OVESCO are limited to superficial or low-risk malignancy lesions (eg, adenomas, early cancers or subepithelial tumors), not suitable to conventional endoscopic resection or in patients with a severe surgical risk. Both en bloc resection rate and complication rate are aligned with other authors' data.

CONCLUSIONS

EFTR by FTRD system represents an effective and safe options whenever a recurrent lesion in a challenging environment occurres (eg, recent scar, low rectum or beyond a large colonic bend). Procedure-related adverse events are potentially severe, so that this novel technique should be performed by "expert hands".

KEY WORDS

Difficult polypectomies, Early carcinomas, Endoscopic Full-Thickness Resection (EFTR), Full-Thickness Resection Device (FTRD) by Over-The-Scope (OVESCO) clip closure, Literature overview, Single center experience.

A minimally invasive lens-free computational microendoscope

Ultra-miniaturized microendoscopes are vital for numerous biomedical applications. Such minimally invasive imagers allow for navigation into hard-to-reach regions and observation of deep brain activity in freely moving animals. Conventional solutions use distal microlenses. However, as lenses become smaller and less invasive, they develop greater aberrations and restricted fields of view. In addition, most of the imagers capable of variable focusing require mechanical actuation of the lens, increasing the distal complexity and weight. Here, we demonstrate a distal lens-free approach to microendoscopy enabled by computational image recovery. Our approach is entirely actuation free and uses a single pseudorandom spatial mask at the distal end of a multicore fiber. Experimentally, this lensless approach increases the space-bandwidth product, i.e., field of view divided by resolution, by threefold over a best-case lens-based system. In addition, the microendoscope demonstrates color resolved imaging and refocusing to 11 distinct depth planes from a single camera frame without any actuated parts.

Tongue peak pressure: a tool to aid in the identification of obstruction sites in patients with obstructive sleep apnea/hypopnea syndrome

Purpose of this study was to evaluate whether tongue peak pressure measured using the Iowa Oral Performance Instrument is correlated with the topographic site of obstruction in patients with obstructive sleep apnea/hypopnea syndrome observed during drug-induced sleep endoscopy. Thirty-five consecutive adult patients (29 men, 6 women) were prospectively enrolled after having been diagnosed with severe obstructive sleep apnea/hypopnea syndrome by polysomnography. An apnea-hypopnea index > 30 was confirmed, and age, gender, and body mass index were recorded by Epworth Sleepiness Scale questionnaire, and a thorough evaluation of the upper airway by video-flexible endoscopy. Twenty healthy controls according to age and sex were chosen for IOPI measurements. After drug-induced sleep endoscopy, a topographic diagnosis was done using the VOTE classification. Tongue and lip peak pressures were both measured using the Iowa Oral Performance Instrument in all patients and in 20 healthy controls. Main outcomes and measures: the correlations between office findings, Iowa Oral Performance Instrument measures, and the VOTE tongue classification during drug-induced sleep endoscopy (T0, T1, T2) were then investigated. RESULTS: The average Iowa Oral Performance Instrument tongue and lip pressure were 44.02 ± 12.29 and 15.03 ± 3.71 kPa, respectively. The Iowa Oral Performance Instrument scores were both significantly lower than values in healthy controls (P < 0.001). The VOTE classification referring to the tongue position was T0 in 13 cases (37.1%), T1 in 12 cases (34.3%), and T2 in 10 cases (28.6%). A significant correlation was found between the Iowa Oral Performance Instrument tongue pressure and the T size during drug-induced sleep endoscopy (Kruskal-Wallis χ² 25.82; P ≤ 0.001). CONCLUSIONS: In our experience, the Iowa Oral Performance Instrument is a useful tool for evaluating tongue collapse for the topographic diagnosis of patients with obstructive sleep apnea/hypopnea syndrome.

Technological Advances in Endoscopic Equipment in Exotic Pet Medicine

The aim of this article is to review some of the technological advances in endoscopy and endosurgery. The article focuses on a few key areas relevant to exotic pets, including advances in urolith management, visualization, and laparoscopic surgery.

Line scanning, fiber bundle fluorescence HiLo endomicroscopy with confocal slit detection

Fiber bundle fluorescence endomicroscopy is an effective method for in vivo imaging of biological tissue samples. Line-scanning confocal laser endomicroscopy realizes confocal imaging at a much higher frame rate compared to the point scanning system, but with reduced optical sectioning. To address this problem, we describe a fiber bundle endomicroscopy system that utilizes the HiLo technique to enhance the optical sectioning while still maintaining high image acquisition rates. Confocal HiLo endomicroscopy is achieved by synchronizing the scanning hybrid-illumination laser line with the rolling shutter of a CMOS camera. An evident improvement of axial sectioning is achieved as compared to the line-scanning confocal endomicroscopy without the HiLo technique. Comparisons are also made with epifluorescence endomicroscopy with and without HiLo. The optical sectioning enhancement is demonstrated on lens tissue as well as porcine kidney tissue.

Characterization of a multicore fiber image guide for nonlinear endoscopic imaging using two-photon fluorescence and second-harmonic generation

Multiphoton microscopy (MPM) has the capacity to record second-harmonic generation (SHG) and endogenous two-photon excitation fluorescence (2PEF) signals emitted from biological tissues. The development of fiber-based miniaturized endomicroscopes delivering pulses in the femtosecond range will allow the transfer of MPM to clinical endoscopy. We present real-time SHG and 2PEF ex vivo images using an endomicroscope, which totally complies with clinical endoscopy regulations. This system is based on the proximal scanning of a commercial multicore image guide (IG). For understanding the inhomogeneities of the recorded images, we quantitatively characterize the IG at the single-core level during nonlinear excitation. The obtained results suggest that these inhomogeneities originate from the variable core geometries that, therefore, exhibit variable nonlinear and dispersive properties. Finally, we propose a method based on modulation of dispersion precompensation to address the image inhomogeneity issue and, as a proof of concept, we demonstrate its capability to improve the nonlinear image quality.

A review on recent advances in soft surgical robots for endoscopic applications

BACKGROUND

Soft materials, with their compliant properties, enable conformity and safe interaction with human body. With the advance in actuation and sensing of soft materials, new paradigm in robotics called "soft robotics" emerges. Soft robotics has become a new approach in designing medical devices such as wearable robotic gloves and exoskeleton. However, application of soft robotics in surgical instrument inside human body is still in its infancy.

AIMS

In this paper, current application and design of soft robots specifically applied for endoscopy are reviewed.

MATERIALS & METHODS

Different aspects in the implementation of soft robotics in endoscope design were reviewed. The key studies about MIS and NOTES were reviewed to establish the clinical background and extract the limitations of current endoscopic device in the last decade.

RESULTS AND DISCUSSION

In this review study, the implementation of soft robotics concepts in endoscopic application, with highlights on different features of several soft endoscopes, were evaluated. The progress in different aspects of soft robotics endoscope, current state, and future perspectives were also discussed.

CONCLUSION

Based on the survey on the structural specification, actuation, sensing, and stiffening the future soft surgical endoscopes are recommended to fulfil the following specifications: safe especially from pressure leakage, fully biocompatible materials, MR-compatible, capable for large bending in at least two antagonistic directions, modularity, adjustable stiffness.

Application of lacrimal endoscopy in the diagnosis and treatment of primary canaliculitis: Practical technique and graphic presentation

To investigate the efficacy of lacrimal endoscopy in the diagnosis and treatment of primary canaliculitis.This is a retrospective, interventional study. Fifteen patients diagnosed as primary canaliculitis were investigated, who underwent surgery with lacrimal endoscopy from January 2015 to December 2017 at Zhejiang Provincial People's Hospital. Patients were subsequently followed post-operatively for at least 6 months. Pre- and post-operative main measurement included ocular surface symptoms, signs of canaliculitis, intraoperative images, treatment response and complications.Twelve patients (12 eyes) were enrolled. Endoscopy was successful in revealing the residual concretion and pathological change of lacrimal duct. With its unique direct vision and micro drill, all concretions got removed and lacrimal ducts got patent. On postoperative month 6, all of the patients got cured with no signs of redness, swelling of the punctum and eyelid, epiphora with discharge and pain. None serious complications such as false canalicular passage were observed.Lacrimal endoscopy is indispensable in diagnosis, treatment and follows up of primary canaliculitis. With less iatrogenic injury, higher resolution rate and direct observation of canalicular mucosa, lacrimal endoscopy should be widely applied in the management of lacrimal diseases.

The effect of high-speed videoendoscopy configuration on reduced-order model parameter estimates by Bayesian inference

Bayesian inference has been previously demonstrated as a viable inverse analysis tool for estimating subject-specific reduced-order model parameters and uncertainties. However, previous studies have relied upon simulated glottal area waveforms with superimposed random noise as the measurement. In practice, high-speed videoendoscopy is used to measure glottal area, which introduces practical imaging effects not captured in simulated data, such as viewing angle, frame rate, and camera resolution. Herein, high-speed videos of the vocal folds were approximated by recording the trajectories of physical vocal fold models controlled by a symmetric body-cover model. Twenty videos were recorded, varying subglottal pressure, cricothyroid activation, and viewing angle, with frame rate and video resolution varied by digital video manipulation. Bayesian inference was used to estimate subglottal pressure and cricothyroid activation from glottal area waveforms extracted from the videos. The resulting estimates show off-axis viewing of 10° can lead to a 10% bias in the estimated subglottal pressure. A viewing model is introduced such that viewing angle can be included as an estimated parameter, which alleviates estimate bias. Frame rate and pixel resolution were found to primarily affect uncertainty of parameter estimates up to a limit where spatial and temporal resolutions were too poor to resolve the glottal area. Since many high-speed cameras have the ability to sacrifice spatial for temporal resolution, the findings herein suggest that Bayesian inference studies employing high-speed video should increase temporal resolutions at the expense of spatial resolution for reduced estimate uncertainties.

The effect of high-speed videoendoscopy configuration on reduced-order model parameter estimates by Bayesian inference

Bayesian inference has been previously demonstrated as a viable inverse analysis tool for estimating subject-specific reduced-order model parameters and uncertainties. However, previous studies have relied upon simulated glottal area waveforms with superimposed random noise as the measurement. In practice, high-speed videoendoscopy is used to measure glottal area, which introduces practical imaging effects not captured in simulated data, such as viewing angle, frame rate, and camera resolution. Herein, high-speed videos of the vocal folds were approximated by recording the trajectories of physical vocal fold models controlled by a symmetric body-cover model. Twenty videos were recorded, varying subglottal pressure, cricothyroid activation, and viewing angle, with frame rate and video resolution varied by digital video manipulation. Bayesian inference was used to estimate subglottal pressure and cricothyroid activation from glottal area waveforms extracted from the videos. The resulting estimates show off-axis viewing of 10° can lead to a 10% bias in the estimated subglottal pressure. A viewing model is introduced such that viewing angle can be included as an estimated parameter, which alleviates estimate bias. Frame rate and pixel resolution were found to primarily affect uncertainty of parameter estimates up to a limit where spatial and temporal resolutions were too poor to resolve the glottal area. Since many high-speed cameras have the ability to sacrifice spatial for temporal resolution, the findings herein suggest that Bayesian inference studies employing high-speed video should increase temporal resolutions at the expense of spatial resolution for reduced estimate uncertainties.

A Systematic Review of Disposable Sheath Use During Flexible Endoscopy

Flexible endoscopes are exposed to blood, mucus, and other secretions during procedures. Single-use sheaths are designed to prevent contact between contaminants and reusable endoscope components. This systematic review examined findings from 22 studies that assessed endoscopic sheath use during urologic, gastrointestinal, or respiratory procedures. The evidence showed that sheaths were durable and yielded faster endoscope turnover times because their reusable components did not require high-level disinfection or sterilization. After a brief learning period, health care providers successfully assembled and maneuvered sheathed endoscopes. Patients generally did not experience greater discomfort during procedures in which sheaths were used. Microbial cultures of sheathed endoscopes were negative or similar to unsheathed endoscopes. More research is needed to evaluate the potential effect of disposable sheaths on infection risks. The evidence suggests that sheaths are a viable option for reliably providing a barrier between endoscopes and patients without affecting the quality of endoscopic procedures.

Is biportal technique/endoscopic spinal surgery satisfactory for lumbar spinal stenosis patients?: A prospective randomized comparative study

BACKGROUND

Lumbar decompressive surgery is a standard surgical technique for lumbar spinal stenosis. Many new surgical techniques have been introduced, ranging from open surgery to minimally invasive procedures. Minimally invasive surgical techniques are preferred because patients experience less postoperative pain and shorter hospital stays. However, the success rate of minimally invasive techniques have been controversial. The object of this study was to assess the feasibility of spinal decompression using biportal technique/endoscopic surgery compared with microscopic surgery.

METHODS

Seventy lumbar spinal stenosis patients undergoing laminectomy were included in this study. A number table was used to randomize the patients into two groups: a biportal technique/endoscopic surgery group (BG-36) and a microscopic surgery group (OG-34). One surgeon performed either biportal technique/endoscopic decompression or microscopic decompression using a tubular retractor, depending on the group to which the patient was randomized. Perioperative data and clinical outcomes at postoperative 6 months were collected and analyzed.

RESULTS

The demographic data and level of surgery were comparable between the two groups. A shorter operation time (36 ± 11 vs 54 ± 9 min), less hemovac drain output (25.5 ± 15.8 vs 53.2 ± 32.1 ml), less opioid usage (2.3 ± 0.6 vs 6.5 ± 2.5 T) and shorter hospital stay (1.2 ± 0.3 vs 3.5 ± 0.8 days) were shown in BG. The BG experienced no significant differences in clinical outcomes compared with OG. Favorable clinical outcomes were shown at 6 months after surgery in both groups.

CONCLUSION

Lumbar decompressive surgery using biportal technique/endoscopy showed favorable clinical outcomes, less pain and a shorter hospital stay compared to microscopic surgery in patients with lumbar spinal stenosis.

Endoscopic optical coherence tomography angiography using a forward imaging piezo scanner probe

A forward imaging endoscope for optical coherence tomography angiography (OCTA) featuring a piezoelectric fiber scanner is presented. Imaging is performed with an optical coherence tomography (OCT) system incorporating an akinetic light source with a center wavelength of 1300 nm, bandwidth of 90 nm and A-line rate of 173 kHz. The endoscope operates in contact mode to avoid motion artifacts, in particular, beneficial for OCTA measurements, and achieves a transversal resolution of 12 μm in air at a rigid probe size of 4 mm in diameter and 11.3 mm in length. A spiral scan pattern is generated at a scanning frequency of 360 Hz to sample a maximum field of view of 1.3 mm. OCT images of a human finger as well as visualization of microvasculature of the human palm are presented both in two and three dimensions. The combination of morphological tissue contrast with qualitative dynamic blood flow information within this endoscopic imaging approach potentially enables improved early diagnostic capabilities of internal organs for diseases such as bladder cancer.

Endoscopic optical coherence tomography angiography using a forward imaging piezo scanner probe

A forward imaging endoscope for optical coherence tomography angiography (OCTA) featuring a piezoelectric fiber scanner is presented. Imaging is performed with an optical coherence tomography (OCT) system incorporating an akinetic light source with a center wavelength of 1300 nm, bandwidth of 90 nm and A-line rate of 173 kHz. The endoscope operates in contact mode to avoid motion artifacts, in particular, beneficial for OCTA measurements, and achieves a transversal resolution of 12 μm in air at a rigid probe size of 4 mm in diameter and 11.3 mm in length. A spiral scan pattern is generated at a scanning frequency of 360 Hz to sample a maximum field of view of 1.3 mm. OCT images of a human finger as well as visualization of microvasculature of the human palm are presented both in two and three dimensions. The combination of morphological tissue contrast with qualitative dynamic blood flow information within this endoscopic imaging approach potentially enables improved early diagnostic capabilities of internal organs for diseases such as bladder cancer.