Three techniques for guidewire-assisted sulcus glaucoma tube shunt placement

Purpose

Tube shunts can be inserted into the anterior chamber, ciliary sulcus, or pars plana. Sulcus tube placement can be challenging. This report demonstrates three techniques for guidewire-assisted sulcus tube insertion.

Observations

The first technique uses a needle inserted through a paracentesis 180-degrees across from the tube entry site and creates an ab-interno sclerotomy through which the guidewire is inserted by docking it into the needle bevel. The second technique involves inserting the guidewire into the eye via a paracentesis and using microforceps to retrieve it through a sclerotomy. The third technique uses forceps to insert the guidewire into a paracentesis 180° across from the planned tube entry site and dock it into a needle bevel that has been inserted into the sulcus. Each of these techniques provides a reliable and reproducible way to insert a tube into the sulcus.

Conclusions and importance

Guidewire-assisted tube entry offers a promising solution in cases of difficult sulcus tube placement without substantial additional cost.

Double-guidewire technique for selective biliary cannulation does not increase the rate of post-endoscopic retrograde cholangiopancreatography pancreatitis in patients with naïve papilla

BACKGROUND/AIMS

This study aimed to compare the safety of the double-guidewire technique (DGT) with that of the conventional single-guidewire technique (SGT) in real-world situations.

METHODS

A total of 240 patients with naïve papilla who underwent endoscopic retrograde cholangiopancreatography (ERCP) at Daegu Catholic University Medical Center between January 2021 and December 2021 were included. The primary outcome was the rate of post-ERCP pancreatitis (PEP) in the SGT and DGT groups.

RESULTS

A total of 163 patients (67.9%) belonged to the SGT group, and 77 (32.1%) belonged to the DGT group. The rates of successful biliary cannulation were 95.7% and 83.1% in the SGT and DGT groups, respectively (p=0.002). In the study group, PEP occurred in 14 patients (5.8%). The PEP rates were not significantly different between the SGT and DGT groups (4.3% vs. 9.1%, p=0.150). In the multivariate analysis, the age of <50 years (odds ratio [OR], 9.305; 95% confidence interval [CI], 1.367-63.358; p=0.023) and hyperlipidemia (OR, 7.384; 95% CI, 1.103-49.424; p=0.039) were significant risk factors for PEP in the DGT group.

CONCLUSION

DGT did not increase the PEP rate in patients with naïve papilla. In addition, the age of <50 years and hyperlipidemia were significant risk factors for PEP in the DGT group.

Magnetism-enhanced biomaterial Mg guide wire by MAP process for development of catheter insertion

The surface topography of implant tools has indicated an interfacial contact in degradation still being discovered; however, the glossy texture of a tiny magnesium wire is important for absorbable medical devices. This paper investigated the alterations of surface quality by a magnetic abrasive polishing method using a rotational magnetic field-assisted system with input parameters of revolution, abrasive media, magnetic pole, flux density, vibration, and amplitude that could noticeably enhance asperities along a sample. Furthermore, the blood flow simulation is used to analyze flow within blood vessels while maintaining the surface roughness conditions of the guide wire. The results are compared and discussed. Magnetic field simulation is employed to investigate the magnetic field strength in the polishing zone. Scanning Electron Microscopy (SEM) provides visual aids for recognizing the differences between pre-and post-workpieces of magnesium wire. The experimental results reveal that a wire diameter of 0.50 mm predominantly achieves surface morphology from the initial roughness of 0.22 μm to 0.05 μm. The results corroborate that the distribution of blood in the circulatory system was relatively stable. Hence, this study establishes a crucial benchmark for the precision polishing of ultra-thin magnesium wires, which is vital for their use as high-precision biodegradable medical devices.

Sulcus Tube Internal Needle Guidewire Technique for Glaucoma Drainage Device Placement: Improving Surgical Ease and Precision

INTRODUCTION

Despite the rise of micro-invasive glaucoma surgery (MIGS), glaucoma drainage device implantation continues to be a mainstay among glaucoma surgical treatment options. Anterior chamber tube placement, while effective in reducing intraocular pressure (IOP), poses corneal endothelial risks. Ciliary sulcus tube placement shows promise in reduced corneal endothelial cell loss, but proper sulcus placement can be challenging. Our study describes the initial safety and effectiveness results using  a novel sulcus tube internal needle guidewire (STING) technique for glaucoma drainage device insertion into the ciliary sulcus.

METHODS

We retrospectively reviewed the charts of all consecutive patients who underwent the STING technique using the Ahmed ClearPath, Ahmed Glaucoma Valve, or Baerveldt glaucoma implant with at least 6 months of follow-up. Demographic characteristics, type of glaucoma, previous medical and surgical treatment, pre- and postoperative IOP, pre- and postoperative medications, complications, and success rates were recorded.

RESULTS

Out of nine eyes, seven resulted in qualified success (77.8%). Preoperative mean IOP was 23.8 ± 6.3 mmHg, and postoperative IOP decreased significantly to 14.9 ± 3.7 mmHg (p = 0.008). The average number of preoperative medications per patient was 4.4 ± 0.7, while the average number of postoperative medications per patient was reduced significantly to 3.6 ± 1.0 (p = 0.039).

CONCLUSION

The STING technique is a novel method for placing a glaucoma drainage device into the ciliary sulcus, leading to IOP lowering with minimal complications. The STING technique is designed to improve surgical ease and increase anatomical precision of sulcus tube placement. Video available for this article.

Removal of a guide-wire sliding into abdominal cavity via transgastric natural orifice transluminal endoscopic surgery: A case report

BACKGROUND

Guidewire slippage into the peritoneal cavity during clinical operations is extremely rare. Therefore, this paper aims to report a successful case of guidewire removal using transgastric natural orifice transluminal endoscopic surgery (NOTES). The goal is to enhance physicians' understanding of the management plan for this unique scenario and provide a valuable reference for clinical practice.

CASE SUMMARY

A 64-year-old man presented with abdominal distension and was diagnosed with cirrhosis combined with massive ascites. To proceed with treatment, the patient underwent ultrasound-guided peritoneal puncture and underwent catheterization and drainage. Unfortunately, a 0.035-inch guidewire slipped into the abdominal cavity during the procedure. Following a comprehensive evaluation and consultation by a multidisciplinary team, the guidewire was successfully removed using NOTES.

CONCLUSION

This case highlights the potential consideration of transgastric NOTES removal when encountering a foreign body, such as a guidewire, within the abdominal cavity.

The positional consistency between guidewire and cannulated or solid screw in robot-assisted spinal internal fixation surgery

BACKGROUND

This study aimed to investigate the positional consistency between the guidewire and the screw in spinal internal fixation surgery.

METHODS

This study involved 64 patients who underwent robot-assisted thoracic or lumbar pedicle screw fixation surgery. Guidewires were inserted with the assistance of the Tirobot. Either cannulated screws or solid screws were inserted. Guidewire and screw accuracy was measured using CT images based on the Gertzbein and Robbins scale. The positional consistency between guidewire and screw was evaluated based on the fused CT images, which could graphically and quantitatively demonstrate the consistency. The consistency was evaluated based on a grading system that considered the maximum distance and angulation between the centerline of the guidewire and the screw in the region of the pedicle.

RESULTS

A total of 322 screws were placed including 206 cannulated ones and 116 solid ones. Based on the Gertzbein and Robbins scale, 97.5% of the guidewires were grade A, and 94.1% of the screws were grade A. Based on our guidewire-screw consistency scale, 85% in cannulated group, and 69.8% in solid group, were grade A. Both solid and cannulated screws may alter trajectory compared to the guidewires. The positional accuracy and guidewire-screw consistency in the solid screw group is significantly worse than that in the cannulated screw group. The cortical bone of the pedicle has a positive guide effect on either solid or cannulated screws.

CONCLUSION

The pedicle screws may alter trajectory despite the guidance of the guidewires. Solid screws show worse positional accuracy and guidewire-screw consistency compared with cannulated screws. Trial registration The study was retrospectively registered and approved by our center's institutional review board.

Inadvertent catheter misplacement into the subclavian artery during ultrasound-guided internal jugular venous catheterization: a case report

BACKGROUND

Ultrasound-guided central venous catheterization has become a standard procedure. However, mechanical complications are still reported.

CASE PRESENTATION

An 85-year-old woman presented with coagulopathic bladder tamponade. Ultrasound-guided right internal jugular venous catheterization was planned because of difficult peripheral venous access. A guidewire was advanced through a needle inserted at the midpoint of the right carotid triangle. The guidewire was identified in the short axis, but not in the long-axis ultrasound view, leading to inadvertent insertion of the catheter into the right subclavian artery through the internal jugular vein. Stent graft insertion was performed for perforation closure. The patient exhibited no symptoms of cerebral ischemia following stent graft insertion.

DISCUSSION

This case demonstrated that the needle-sticking site should not be placed close to the clavicle for ultrasound-guided internal jugular venous catheterization, as it may not confirm the position of guidewire in the long-axis ultrasound view.

Numerical Methodology to Evaluate Trackability and Pushability of PTCA Balloon Catheter

PURPOSE

During percutaneous coronary intervention (PCI), the ability to navigate a catheter without causing injury to the vessel and damage to the device is crucial outcome of the procedure. This study aimed to develop a numerical model to analyse the percutaneous transluminal coronary angioplasty (PTCA) catheter navigation in coronary vessels.

METHODS

Trackability and pushability are two major parameters used to characterize the navigation of PTCA balloon catheters, and they are influenced by vessel tortuosity, contact interactions and catheter design. In the current study, finite element analysis model is presented to evaluate trackability and pushability considering two different vessel geometries. Impact of contact interactions among catheter, guidewire, and vessel were studied to validate the numerical model with in vitro test data. Further, a parametric study was conducted to understand the influence of distal shaft, and proximal shaft outer diameter.

RESULTS

Obtained results suggest that contact interaction and co-efficient of friction between guidewire and catheter are critical parameters to obtain numerical results comparable to experimental data. Results from the parametric study predicted strong positive correlation of distal shaft diameter on pushability, and weak correlation on trackability force. Furthermore, parametric variation in proximal shaft diameter has strong positive correlation on trackability force and strong negative correlation on pushability.

CONCLUSION

Numerical methodology presented in this study is a preliminary attempt to simulate the behavior of PTCA balloon catheter navigation. This methodology will be helpful in the design and optimization of PTCA balloon catheter and similar devices with improved deliverability.

Comparison of Percutaneous Coronary Intervention Procedures and Outcomes for Recent and Acute ST-Elevation Myocardial Infarction

Although the primary percutaneous coronary intervention (PCI) is an established treatment for acute ST-elevation myocardial infarction (STEMI), relevant guidelines do not recommend it for recent-STEMI cases with a totally occluded infarcted related artery (IRA). However, PCI is allowed in Japan for recent-STEMI cases, but little is known regarding its outcomes. We aimed to examine the details and outcomes of PCI procedures in recent-STEMI cases with a totally occluded IRA and compared the findings with those in acute-STEMI cases.Among the 903 consecutive patients admitted with acute coronary syndrome, 250 were treated with PCI for type I STEMI with a totally occluded IRA. According to the time between symptom onset and diagnosis, patients were divided into the recent-STEMI (n = 32) and acute-STEMI (n = 218) groups. The background, procedure details, and short-term outcomes were analyzed. No significant differences between the groups were noted regarding patient demographics, acute myocardial infarction severity, or IRA distribution. Although the stent number and type were similar, significant differences were observed among PCI procedures, including the number of guidewires used, rate of microcatheter or double-lumen catheter use, and application rate of thrombus aspiration. The thrombolysis rate in the myocardial infarction flow 3-grade post-PCI did not differ significantly between the groups. Both groups had a low frequency of procedure-related complications. The in-hospital mortality rates were 0% and 4.6% in the recent-STEMI and acute-STEMI groups, respectively (P > 0.05).Although recent-STEMI cases required complicated PCI techniques, their safety, success rate, and in-hospital mortality were comparable to those of acute-STEMI cases.

Over-the-Scope-Clips Can Be Fired Safely Over a Guidewire: Proof of Concept in an Ex-Vivo Porcine Model

Background and Objectives

To assist in achieving optimal position when deploying over-the-scope (OTS)-clips, the concept of cannulating the defect with a guidewire, backloading the endoscope onto the wire, and firing the OTS-clip over the wire with subsequent wire removal has been demonstrated. The safety of this technique has not been evaluated.

Methods

An ex-vivo porcine foregut model was utilized. Biopsy punches were used to create 3-mm diameter full-thickness gastrointestinal tract defects through which a guidewire was threaded. An endoscope was backloaded over the wire and OTS-clips (OVESCO, Tuebingen, Germany) were fired over the mucosal defect and wire. The wire was removed through the endoscope and the removal difficulty was graded using a Likert scale. This process was repeated for each unique combination of nine OTS-clip types, two wire types, four wire angles, and three tissue types. Statistical analysis included t test and ANOVA.

Results

Two hundred sixteen OTS-clip firings with wire removal attempts were performed with the following Likert score breakdown: 1 - No difficulty (80.6%), 2 - mild difficulty (16.2%), 3 - moderate difficulty (2.3%), 4 - extreme difficulty (0.9%), and 5 - unable to remove (0%). Statistically significant differences were noted in removal difficulty between OTS-clip sizes (p < 0.05). No differences were identified between clip teeth types, wire types, tissue types, and wire angles (p > 0.05).

Conclusion

In this ex-vivo model, the guidewire was successfully removed through the endoscope in all cases. This technique can be employed to facilitate OTS-clip closure of gastrointestinal tract defects, but further study is indicated before wide clinical implementation.

Characterization of Surgical Tools for Specific Endovascular Navigation

PURPOSE

The aim of this work was to mechanically characterize a specific active guidewire and catheters that are commercially available, for further implementation into numerical simulation of endovascular navigation towards complex targets.

METHODS

For the guidewire, 3-point bending tests and bending with added masses were used to obtain the Young moduli of its various components. To study its behavior, the guidewire was activated under "ideal" conditions and its performance was investigated. As for the various catheters, they were measured and 3-point bending tests were conducted to determine their mechanical properties.

RESULTS & CONCLUSION

The Young moduli of the shaft and the distal tip of the guidewire were determined. We defined a suitable current intensity to activate the guidewire related to an optimal curvature. Then, the time of activation/deactivation was measured at 1.7 s. On the flip side, parts of the catheters were considered either elastic or viscoelastic. In all cases, the rigidity gradients along the various catheters were highlighted. The characterization of the aforementioned surgical tools provides the opportunity to simulate the endovascular nagivation process.

Safety of Sheathless Transradial Balloon Guide Catheter Placement for Acute Stroke Thrombectomy

BACKGROUND

Transradial access has been described for mechanical thrombectomy in acute stroke, and proximal balloon occlusion has been shown to improve recanalization and outcomes. However, sheathed access requires a larger total catheter diameter at the access site. We aimed to characterize the safety of sheathless transradial balloon guide catheter use in acute stroke intervention.

METHODS

Consecutive patients who underwent sheathless right-sided transradial access for thrombectomy with a balloon guide catheter were identified in a prospectively collected dataset from 2019 to 2021. Demographics, procedure details, and short-term outcomes were collected and reported with descriptive statistics.

RESULTS

A total of 48 patients (20 women) with a mean age of 72.3 years were identified. Of patients, 56.3% had occlusions in the left-sided circulation; 35 (72.9%) had M1 occlusions, 7 (14.6%) had M2 occlusions, and 6 (12.5%) had internal carotid artery occlusions. Tissue plasminogen activator was administered to 16 (33.3%) patients. Five (10.4%) patients underwent intraprocedural carotid stenting. The cohort had successful reperfusion after a median of 1 (interquartile range: 1, 2) pass. Median time from access to recanalization was 31 (interquartile range: 25, 53) minutes. A postprocedural Thrombolysis In Cerebral Infarction score of ≥2b was achieved in 46 (95.8%) patients. Five patients had wrist access site hematomas. All hematomas resolved with warm compresses, and no further intervention was required.

CONCLUSIONS

Sheathless radial access using a balloon guide catheter may be safely performed for acute ischemic stroke with excellent radiographic outcomes. Further investigation is warranted to evaluate the comparative effectiveness of sheathless compared with sheathed transradial balloon guide access.

Usefulness of the double-guidewire technique for endoscopic procedures in the field of biliary and pancreatic diseases

The double-guidewire method has been increasingly used in endoscopic procedures for biliary and pancreatic diseases in recent years, including endoscopic retrograde cholangiopancreatography and endoscopic ultrasonography-related procedures. In addition, double-lumen catheters with uneven distal and proximal lumen openings have been introduced, making it possible to easily create a double-guidewire situation, and the usefulness of the double-guidewire technique using uneven double-lumen cannulas has been widely reported. Although the advantages of using two guidewires depend on the particular situation and the appropriate use of the two guidewires, deepening the knowledge of the double-guidewire method will contribute greatly to troubleshooting in daily practice. In this review, the usefulness of the double-guidewire technique is discussed with respect to two main areas: selective insertion of guidewires and devices and biliary cannulation.

Use of ultrasound to confirm guidewire position in hemodialysis catheter implantation

INTRODUCTION

Hemodialysis is the most used dialysis modality in Brazil for the treatment of end-stage chronic kidney disease and severe acute kidney injury. Non-tunneled, short-term, double-lumen catheters allow immediate vascular access in patients without a definitive vascular access for dialysis treatment. Implantation is performed using the Seldinger technique, traditionally based on anatomical landmarks or with puncture under direct visualization by ultrasonography. Confirmation of the placement of the catheter is usually made with a chest X-ray after the end of the procedure.

OBJECTIVE

To describe the use of ultrasonography to confirm the proper positioning of the guidewire during catheter implantation in real time, ensuring the desired path.

METHODS

We used the Seldinger technique for catheter implantation. The confirmation of the position of the guidewire occurred after the introduction of 50 cm of this wire, as described in the aforementioned technique. A convex transducer was placed longitudinally below the xiphoid process to visualize the guidewire in the inferior vena cava, or transversely at the same location to visualize it in the cavoatrial junction or right ventricle, using the two-dimensional mode of the ultrasound device. After viewing the guidewire, the catheter implantation proceeded.

RESULTS AND DISCUSSION

The technique was performed in 1549 patients, and regarded 2596 catheter implantations over a period of 5 years and 9 months. The only complication observed was local hematoma, occurring in 0.1% of cases.

CONCLUSION

Confirmation of guidewire position with ultrasonography during catheter implantation is recommended because it is safe, low cost and ensures correct catheter direction.

Evaluation of a diluted lipid emulsion solution as a lubricant for improved peripherally inserted central catheter guidewire removal in a neonatal population

BACKGROUND

Medical management of neonates is often established upon safe and reliable vascular access, frequently utilized to provide physiological monitoring, parenteral and supportive treatments, and diagnostic and/or procedural purposes. For this, peripherally inserted central catheters (PICCs) are often used to provide safe vascular access and infusion-related therapies in the neonatal intensive care (NICU) setting.

PURPOSE

Difficult PICC guidewire removal is understood to cause catheter damage, causing luminal rupture or possible breakage of the catheter or guidewire itself. The aim of this study was to assess and compare the incidence of therapy failures with use of a preflush fluid using normal saline (NSS) versus a diluted lipid solution (DLS) prior to device insertion, to assist with guidewire removal and prevent unnecessary catheter damage.

METHOD AND SETTING

A retrospective, observational study was performed in the Neonatal Intensive Care Unit (NICU) of the Women's Wellness and Research Centre, Hamad Medical Corporation, Qatar. This single site study included 507 neonates who required intravenous therapy administered via a PICC during the study period.

RESULTS

Results demonstrated the use of a diluted lipid solution preflush (DLS) resulted in significantly lesser failures, when compared with the control group (NSS). This highlights a clinical significance after adjusting for day of insertion, gestational age, birth weight and catheter type.

CONCLUSION

DLS preflush demonstrated a benefit over the use of a NSS preflush to enhance PICC guidewire removal in neonatal patients in the NICU. The risk for development of maintenance-related complications leading to premature device removal decreased significantly if the DLS preflush was used. During the study period, no complications related to the use of a lipid preflush solution were identified.

IMPLICATIONS FOR PRACTICE AND RESEARCH

This may be the first study published investigating and supporting guidewire removal enhancement by using a diluted lipid/saline preflush solution. When the requirement for vascular access is most pertinent in the neonate, using a diluted lipid preflush may provide an effective method to assist in guidewire removal to prevent malposition and vascular device complications in the neonatal population.

Effect of guidewire insertion in fractional flow reserve procedure for real geometry using computational fluid dynamics

BACKGROUND

Coronary artery disease is an abnormal contraction of the heart supply blood vessel. It limits the oxygenated blood flow to the heart. Thus, diagnosing its severity helps physicians to select the appropriate treatment plan. Fractional flow reserve (FFR) is the most accurate method to pinpoint the stenosis severity. However, inserting the guidewire across stenosis may cause a false overestimation of severity.

METHODS

To estimate the errors due to guidewire insertion, reconstructed three-dimensional coronary artery geometry from a patient-specific scan is used. A comprehensive three-dimensional blood flow model is developed. Blood is considered non-Newtonian and the flow is pulsatile. The model is numerically simulated using realistic boundary conditions.

RESULTS

The FFR value is calculated and compared with the actual flow ratio. Additionally, the ratio between pressure drop and distal dynamic pressure (CDP) is studied. The obtained results for each case are compared and analyzed with the case without a guidewire. It was found that placing the guidewire leads to overestimating the severity of moderate stenosis. It reduces the FFR value from 0.43 to 0.33 with a 23.26% error compared to 0.44 actual flow ratio and the CDP increases from 5.31 to 7.2 with a 35.6% error. FFR value in mild stenosis does not have a significant change due to placing the guidewire. The FFR value decreases from 0.83 to 0.82 compared to the 0.83 actual flow ratio.

CONCLUSION

Consequently, physicians should consider these errors while deciding the treatment plan.

The curative effect analysis of peripherally inserted central venous catheter catheterization for tumor patients under the guidance of new medical guide wire

Objective

To report a method of PICC catheterization with the aid of a new medical guide wire, and to discuss the curative effect.

Methods

Five hundred and thirteen patients who visited our hospital from January 2013 to December 2019 for PICC catheterization were selected as study subjects. Random number method was used to group patients. General information was recorded for both groups. Patients in the observation group received catheterization with the aid of a new medical guide wire. The control group received catheterization via conventional guide wire. The success rate of the first catheterization, the success rate of the catheterization, the timing of the catheterization, the complications and the position of the catheter end were compared between the two groups.

Results

There was no significant difference in general information between the two groups. After analyzing the puncture situation of the two groups, it was found that the average catheterization time of the observation group was shorter than that of the control group, and the difference was statistically significant. Patients in the observation group had higher success rate of one-time catheterization and catheterization success rate, and the difference was statistically significant. The incidences of occult thrombosis, phlebitis and catheter blockage in the observation group were lower than those in the control group, and the difference was statistically significant. The incidence of dominant thrombosis and bleeding at puncture point in the observation group was also lower than that in the control group, but the difference was not statistically significant.

Conclusion

The new type of medical guide wire component is effective for PICC catheterization and worthy of further promotion.

A novel technique for Endobronchial Watanabe Spigot placement for bronchopleural fistula: a traction method

Empyema with bronchopleural fistula is a challenging condition that often requires open-window thoracostomy. Bronchial occlusion with Endobronchial Watanabe Spigot is an effective and less invasive procedure to close the fistula; however, delivering a spigot into the target bronchus requires high technical skills. Herein, we report a case of bronchopleural fistula occluded with a spigot using a new 'traction method' in which the spigot is tied as an anchor to a guidewire and pulled into the target bronchus. Our method allows selective and steady placement of the spigot for patients who undergo open-window thoracostomy for the treatment of bronchopleural fistula.

Open surgery retrieval of a missing guidewire causing cerebral infarctions after cerebral angiography: a case report

BACKGROUND

Intra-aortic foreign body (IAFB) is uncommon, which is usually caused by a rupture of the catheter or guidewire. IAFB can cause catastrophic complications, including arrhythmia, embolization of guidewire fragments, intravascular clipping of the guidewire and vascular perforation. However, there are still no guidelines on removal and management of IAFB. Here, we present a rare case of fractured cerebral angiographic guidewires in the aorta that resulted in multiple cerebral infarctions.

CASE PRESENTATION

A 50-year-old man experienced new cerebral infarction after cerebral angiography. Computed tomography and echocardiography demonstrated foreign bodies in his ascending aorta and aortic arch. Open surgery was successfully performed to retrieve the guidewires. The postoperation and follow-up was uneventful.

CONCLUSION

It is very important for interventional radiologists to check the catheter and guidewire after operation and perform ultrasound or radiograph to prevent IAFB. Additionally, the effective management of IAFB requires the early detection and the selection of appropriate treatment options, as well as long-time follow up.

Horseshoe kidney leading to ERCP failure; innovative use of guide wire during laparoscopic CBD exploration: A case report

INTRODUCTION

Horseshoe kidneys are the most common fusion defect of the kidneys, which amounts to about 0.25% of the population. They are usually asymptomatic and are often identified incidentally. The horseshoe kidney can push the second and third part of the duodenum anteriorly, leading to an altered CBD course. Choledocholithiasis is seen in approximately 10-15% of patients with cholelithiasis. Presently, the most preferred approach for managing CBD stones is ERCP. However, in ERCP failure cases, Laparoscopic CBD exploration is the primary treatment modality, with or without T-tube use, with all the advantages of minimally invasive surgery.

CASE PRESENTATION AND DISCUSSION

A 65-year-old female presented with complaints of pain in the right hypochondriac region for three months associated with nausea, jaundice, and loss of appetite and weight. Her USG abdomen showed cholelithiasis with dilated CBD with horseshoe kidney with severe hydronephrosis of the left kidney. They are usually asymptomatic and are often identified incidentally. In this patient, it was believed that the horseshoe kidney had pushed the second and third part of the duodenum anteriorly, leading to an altered CBD course leading to ERCP failure. MRCP confirmed cholelithiasis with choledocholithiasis with dilated CBD of 11.3 mm with horseshoe kidney. ERCP was attempted but was unsuccessful due to non-visualization of the papilla due to overcrowding of duodenal folds. For patients with ERCP failure, laparoscopic CBD exploration is mandatory. For this patient, the CBD was cannulated with a guidewire, if needed, for repeat ERCP and was closed with T-tube in situ.

CONCLUSION

There are no particular preoperative indicators that can predict the failure of ERCP. However, in ERCP failure cases, laparoscopic CBD exploration (with or without T-tube use) is the primary treatment modality.

Ball tipped guide wire for broken nail removal: a case report

A broken intramedullary nail is a well-known complication of non-union of femur shaft fractures. Numerous surgical techniques have been presented before in patients with non-union of long bone fractures. We report the surgical technique used to perform removal of the broken distal segment of a nail in a patient who achieved uneventful union after intramedullary nailing of closed femur shaft fracture. A ball-tipped guidewire was inserted through the broken segment of the femur nail. A pre-bend plain wire was then inserted. With the help of a vise-grip, both wires were twisted in order to make a secure handle between guidewires and a broken implant. With the help of a mallet upward-directed blows were applied to extract a broken segment of the nail. We found ball-tipped guidewire technique a useful and effective technique in removing the broken distal portion of the nail.

Distal catheter lengthening in pediatric patients with hydrocephalus using a guidewire-assisted technique

PURPOSE

The aim of this study was to evaluate the lengthening or replacement of the peritoneal catheter in a ventriculoperitoneal shunt by using a simple guidewire-assisted technique. Here we report on our experience with this methodology, its indications, caveats, and contraindications.

METHODS

A prospective study was performed in 59 consecutively shunted children who required elective lengthening of the peritoneal catheter (25 females and 34 males, mean 10.5 + 4.2 years). The procedure required an incision of only 1 cm over the distal catheter. The catheter was sectioned, and a soft hydrophilic guidewire was inserted into the exposed end of it, which serves as a route for the guidewire to reach the intraperitoneal space. The procedure was followed by the replacement of the patient's catheter with one with additional length as considered appropriate, prior to putting additional slots in the last 5 to 8 cm of the new catheter.

RESULTS

The technique was used in 62 CSF shunts (3 patients had a double derivative system). Fifty-five of the 62 (89%) procedures performed were effective. A conventional peritoneal opening technique was used in the 7 unsuccessful attempts. One patient presented a migration of the abdominal catheter during the first days after surgery. No incident of peritoneal perforation was associated with this technique, nor were any infections or other early or late complications associated with this surgical procedure.

CONCLUSION

The technique we propose permits the peritoneal catheter of a derivative system to be lengthened or replaced in a manner that is simple, fast, and safe.

A preclinical animal model for evaluating the sealing capacity of covered stent grafts in acute vessel perforation

Background

Percutaneous coronary intervention is among the most common therapeutic interventions in cardiology. This procedure may, however, be associated with a rare, though life-threatening complication: acute coronary perforation (CP). CP is primarily treated using covered stents, which are made of bare metal stents with a polytetrafluoroethylene (PTFE) or polyurethane coating. These stents’ major limitations include higher rates of thrombus formation and restenosis. Hence, there is a still unmet need for new stents regarding their design and composition. Or, to test new covered stent designs, the rabbit iliac artery has become the best-established animal model. This study sought to present a preclinical animal approach designed to test covered stents that are utilized following vessel perforation.

Methods

The animal experiments were performed using New Zealand white rabbits, each weighting 3.5–4.5 kg. The animal models described herein relied on the three most common clinical causes for CP, such as guidewire-induced, balloon catheter bursting, and device oversizing. Moreover, the sealing capacity of covered stent grafts was assessed for each of these models by means of angiography.

Results

We herein report a rabbit iliac artery perforation model using three different types of vessel perforation that closely mimic the clinical setting, such as guidewire-induced, balloon catheter rupture, and device oversizing. Using the same rabbit iliac perforation model, we additionally assessed the sealing capacity of a covered stent graft for each model.

Conclusions

The novel rabbit iliac artery perforation models, as described in this report, represent promising animal testing approaches. While their setting is very similar to the real-life context encountered in humans, all three models are based on an animal model that is ideally suited for evaluating the sealing capacity and performance of new medical devices for humans.

Filling of Polyglycolic Acid Sheets for Closure of Gastrointestinal Fistulas With an Easily Deliverable Technique Using a Guidewire

Background

This retrospective study aimed to investigate the suitable indications, methodology and long-term effect of the closure of gastrointestinal (GI) fistulas using polyglycolic acid (PGA) sheets and fibrin glue (FG) and to evaluate the usefulness of a delivery technique using a guidewire.

Methods

It involved 10 applications in six patients (median age 73 (range 53 - 78) years old, three men) with GI fistulas. A guidewire was introduced endoscopically or percutaneously into the fistula beyond the opposite orifice of the fistula with radiologic control. A tapered catheter was inserted over the guidewire, and the fistula was cleaned with an adequate quantity of saline. Subsequently, a small piece of PGA sheet was skewered onto the guidewire at the center and then pushed using the tapered catheter over the guidewire and delivered into the fistula. In cases of endoscopic procedure, the mucosa around the fistula was ablated, and the orifice of the fistula along with the surrounding mucosa was shielded with a piece of PGA sheet fixed with hemoclips and FG.

Results

Technical success of fistula closure was achieved in all applications, and no complications were observed after the procedure. The long-term occlusion of the fistula was ultimately achieved in four of six patients at 202 - 654 days (median duration, 244 days) after the last procedure with one or two applications.

Conclusions

The closure of GI fistulas using PGA sheets and FG demonstrated long-term efficacy for upper GI fistula of a certain length, and the filling technique using a guidewire ensured a safe smooth procedure.

Pyramid attention recurrent networks for real-time guidewire segmentation and tracking in intraoperative X-ray fluoroscopy

In endovascular and cardiovascular surgery, real-time and accurate segmentation and tracking of interventional instruments can aid in reducing radiation exposure, contrast agent and processing time. Nevertheless, this task often comes with the challenges of the elongated deformable structures with low contrast in noisy X-ray fluoroscopy. To address these issues, a novel efficient network architecture, termed pyramid attention recurrent networks (PAR-Net), is proposed for real-time guidewire segmentation and tracking. The proposed PAR-Net contains three major modules, namely pyramid attention module, recurrent residual module and pre-trained MobileNetV2 encoder. Specifically, a hybrid loss function of both reinforced focal loss and dice loss is proposed to better address the issues of class imbalance and misclassified examples. Quantitative and qualitative evaluations on clinical intraoperative images demonstrate that the proposed approach significantly outperforms simpler baselines as well as the best previously published result for this task, achieving the state-of-the-art performance.

Analysis of the effect of guidewire position on stenosis diagnosis using computational fluid dynamics

BACKGROUND

Fractional flow reserve is an accurate method for diagnosing stenosis. The difficulty in using this procedure lies in placing the guidewire precisely at the blood vessel centerline. Owing to the long distance between the insertion point and the stenosis, a guidewire inclination can occur. Therefore, the main objective of this study is to investigate how the measured pressure in a blood vessel varies with the guidewire position.

METHODS

A three-dimensional model of blood flow is developed and numerically simulated. Two positions and two inclination angles from the blood vessel centerline and three throat diameters are investigated. The predicted results are validated using the available experimental data. The predicted results and actual measurements are observed to agree well with each other.

RESULTS

The pressure drop coefficient (CDP) increases because of guidewire insertion. When the guidewire is placed at inclined positions in moderate stenosis, the values of CDP are 66 and 68, depending on the inclination angle; the errors in CDP are 69% and 76%, respectively. At a high flow rate, the errors are reduced to 67% and 70%, respectively. The error in the CDP ranges from 42% to 61% when the guidewire is placed parallel to the centerline. For severe stenosis, the CDP is nearly the same at all positions and varies between 240 and 250; without a guidewire, the CDP is 163.

CONCLUSIONS

The findings confirmed that practitioners should be aware of the guidewire position during the operation. The displacement of the guidewire should be estimated, and the corresponding error must be considered.

Image intensification - A solution for difficult guidewire insertion for central venous access: A case report

Presentation of case

A 56-year old male presented for an elective redo-sternotomy, aortic valve replacement, tricuspid valve annuloplasty, and coronary artery bypass grafting. During central vascular access using a standard Seldinger technique, resistance to two spring-wire guide wires was encountered when the wires were advanced through the patient's internal jugular vein. Ultrasound provided limited views of the anatomical path of the guidewires and was unable to provide visualisation of the level or cause of obstruction. We describe the application of continuous image intensification to successfully identify the anatomical location and safe circumnavigation of guidewire obstruction during the insertion of a central venous and pulmonary artery catheter for cardiac surgery.

Discussion

The use of x-ray image intensification enabled the immediate identification of the cause of obstruction, minimising further attempts at guidewire insertion and subsequent complications. The direct real-time visualisation allowed for manoeuvres such as wire manipulation, rotation and advancement to be safely performed.

Conclusion

Image intensification may decrease malposition rates and mechanical complications associated with difficult central venous catheterisation. Further research comparing the safety and efficiency of ultrasound-guided and fluoroscopy-guided CVC insertion should be contemplated.

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Multiple attempts at central line placement are associated with higher rates of complications.

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Image intensification can be used with ultrasound to facilitate the safe placement of central venous/pulmonary artery catheters.

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Image intensification can provide continuous and real-time visualisation of the guidewire along the vessel's anatomical course.

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Image intensification may decrease malposition and mechanical complications associated with difficult central venous access.

Guidewire Entrapped in the Right Ventricle: A Rare Complication of Hemodialysis Catheter Insertion

How to cite this article: Verma A, Chitransh V, Jaiswal S, Vishen A, Sheikh WR, Haldar M, et al. Guidewire Entrapped in the Right Ventricle: A Rare Complication of Hemodialysis Catheter Insertion. Indian J Crit Care Med 2020;24(1):80–81.

In Response to Guidewire Entrapped in the Right Ventricle: A Rare Complication of Hemodialysis Catheter Insertion

Verma et al. meticulously prevented the further complications once they recognize the entrapped guidewire in the right ventricle. Authors were very correct to mention overzealous insertion of the guidewire without watching the monitor, which may lead to such complications; however, every time monitor is not available for assistance. The Seldinger technique is routinely used for inserting central venous (CV) and hemodialysis (HD) catheters; however, both are different entities and their designs and lengths including of their guidewires vary. During guidewire insertions, simply adhering to the safe length may prevent or minimize many guidewire-related complications.

Use of a radiofrequency guidewire to simplify workflow for left atrium access: a case series

PURPOSE

Transseptal puncture (TSP) is widely used in catheter-based cardiac procedures to gain left atrial access, but its workflow has remained largely unchanged in the last 50 years. This study evaluated the safety and efficacy of a novel, simplified technique for TSP with a radiofrequency (RF)-powered guidewire that eliminates multiple exchanges required with standard needles.

METHODS

TSP was performed in 84 patients undergoing left-sided procedures (72 atrial fibrillation ablations [32 RF, 40 cryoballoon], 4 atrial tachycardia ablations, 2 ventricular arrhythmia ablations, 6 left atrial appendage closure) utilizing a stiff, exchange length RF guidewire. Under fluoroscopic and echocardiographic guidance, the RF guidewire was used to facilitate septal puncture with RF energy and provide a rail for advancing catheters to the left atrium without exchange. All procedures were performed under general anesthesia or sedation.

RESULTS

TSP was achieved in all patients with no complications. The RF guidewire allowed catheters to be tracked back up to the superior vena cava without exchange in cases where another dropdown was desired to locate a preferred puncture site. The stiffness of the wire provided adequate support to advance all sheaths to the left side regardless of outer diameter.

CONCLUSION

TSP was performed safely and successfully for various left heart procedures with a RF guidewire that served as an RF transseptal device and a stiff guidewire. This allowed for a more efficient and potentially safer technique without the need for re-wiring or an over the wire sheath exchange. This provides substantial savings in both time and materials.

Resection of recurrent third branchial cleft fistulas assisted by flexible pharyngotomy

BACKGROUND

Treatment of fistulas arising from the third branchial cleft includes endoscopic cauterization or open cervical fistulectomy. Both approaches are associated with recurrence rates of 14%-18%, and possibly greater rates when the fistula has been treated operatively beforehand. Treatment of fistulas arising from the third branchial cleft is associated with an inordinate recurrence rate. Recurrence may be multifactorial and related to incomplete resection of all of the anatomical elements of the fistula.

AIM

To present a new approach that involves complete resection of the recurrent fistula by a combined therapeutic approach.

METHODS

Here, 12 adult patients diagnosed with recurrent third branchial cleft fistulas underwent a combined therapy assisted by flexible fiber-optic pharyngoscopy to identify and resect the entry site of the fistula into the pyriform sinus. The fistulous opening into the pyriform sinus was identified by flexible fiber-optic pharyngoscopy. The application of intubation with a guidewire by pharyngoscopy, in addition to the removal of the partial excision of the thyroid cartilage, allowed complete resection of the opening and all parts of the fistula tract.

RESULTS

All of the internal openings of the fistulas in the pharynx were found and easily identified by flexible fiber-optic pharyngoscopy. All of the 12 patients underwent complete resection of the recurrent fistula by the combined therapeutic approach. There were no postoperative complications such as parapharyngeal abscess or wound infection, injury or dysfunction of the recurrent laryngeal or superior laryngeal nerves. The pharyngeal edema had degraded, and the pharyngeal wound healed postoperatively within 1 wk. Laryngeal endoscopy and voice analysis were performed on the 14th d post-operatively. Vocal cord movements did not change. The characters of voice for jitter, shimmer, and normalized noise energy were all within normal limits. In addition, no recurrences were observed during the 13-60 mo follow-up period.

CONCLUSION

It can be concluded that the proposed combined therapy is associated with excellent results, minimal morbidity, and no recurrence.

Cardiovascular magnetic resonance-guided right heart catheterization in a conventional CMR environment - predictors of procedure success and duration in pulmonary artery hypertension

BACKGROUND

Cardiovascular magnetic resonance imaging (CMR) is valuable for the investigation and management of pulmonary artery hypertension (PAH), but the direct measurement of pulmonary hemodynamics by right heart catheterization is still necessary. CMR-guided right heart catheterization (CMR-RHC) combines the benefits of CMR and invasive cardiac catheterization, but its feasibility in patients with acquired PAH has not been established. The aims of this study are to: (1) demonstrate the feasibility of CMR-RHC in patients being assessed for PAH in a conventional diagnostic CMR scanner room; (2) determine the predictors of (i) procedure duration, and (ii) procedural failure or technical difficulty as determined by the adjunctive need for a guidewire.

METHODS

Fifty patients investigated for suspected or known PH underwent CMR-RHC. Durations of separate procedural components were recorded, including time taken to pass the catheter from the femoral vein to a stable wedge position (procedure time) and total time the patient spent in the CMR department (department time). Associations between procedural failure/guidewire usage and hemodynamic/CMR measures were assessed using logistic regression. Relationships between procedure times and hemodynamic/CMR measures were evaluated using Spearman's correlation coefficient.

RESULTS

A full CMR-RHC study was successfully completed in 47 (94%) patients. CMR-conditional guidewires were used in 6 (12%) patients. Metrics associated with guidewire use/procedural failure were higher mean pulmonary artery (PA) pressures (mPAP: OR = 1.125, p = 0.018), right heart dilatation (right ventricular (RV) end-systolic volume (RVESV): OR = 1.028, p = 0.018), RV hypertrophy (OR = 1.050, p = 0.0067) and RV ejection fraction (EF) (OR = 0.914, p = 0.014). Median catheter and department times were 3.6 (2.0-7.7) minutes and 60.0 (54.0-68.5) minutes, respectively. All procedure times became significantly shorter with increasing procedural experience (p < 0.05). Catheterization time was also associated with PH severity (RV systolic pressure: rho = 0.46, p = 0.0013) and increasing RV end-systolic volume (RVESV: rho = 0.41, p = 0.0043), hypertrophy (rho = 0.43, p = 0.0025) and dysfunction (RVEF: rho = - 0.32, p = 0.031).

CONCLUSIONS

This study demonstrates that CMR-RHC using standard technology can be incorporated into routine clinical practice for the investigation of PAH. Procedural failure was rare but more likely in patients with severe PAH. Procedure time is clinically acceptable and increases with worsening PAH severity.

Guidewire Mishap: An Avoidable Iatrogenic Complication

Central vein catheterization is a commonly used technique in indoor patients. It is mainly used for venous access, allowing administration of drugs, fluids, chemotherapy, blood components. Central vein catheterisation may lead to many complication which includes bleeding, perforation of veins and hematoma formation, thrombosis, infections, bleeding, needle stick injury, air embolism, kinking or looping of the wire tip, breakage of a guidewire, etc. We, hereby, report a case where the guidewire was lost during femoral venous catherisation. A whole guidewire embolization is completely preventable complication. It may not necessarily produce any symptoms and may remain unnoticed for long time.

How to cite this article

Rani A, Malik PK. Guidewire Mishap: An Avoidable Iatrogenic Complication. Indian J Crit Care Med 2019;23(8):382-383.

Technical Reports of Endoscopic Retrograde Cholangiopancreatography Guidewires on the Basis of Physical Properties

Background/Aims

Using an appropriate guidewire can increase the success rate of selective cannulation in endoscopic retrograde cholangiopancreatography. The purpose of this technical study was to investigate the characteristics of each guidewire type and to evaluate its efficiency and rapidity of insertion.

Methods

We conducted a three-point bending test using a universal testing machine to investigate the flexibility and bending features of each guidewire. 3D-printed silicone tubes with various types of stricture and a hand-made biliary tree silicone model with six-stranded intrahepatic ducts were used to evaluate the success rate and insertion time of each guidewire.

Results

In the three-point bending test, the characteristics of each guidewire were classified. We found that the bending strengths and times were independent of shaft thickness. Using two in vitro biliary duct models, we determined that the success rate and total insertion time were better for guidewires with a resilient shaft and angled tip than for other types of guidewires (p<0.001). Although thickness of the guidewire affected the success rate (p<0.05), it did not affect the total insertion time (p≥0.05).

Conclusions

Among several types of guidewire, some factors (resilient shaft, highly flexible, and angled tip) appeared to be associated with the efficiency and rapidity of the guidewire insertion.

Hybrid treatment of symptomatic carotid disease

Hybrid treatment is a well reported technique for tandem carotid artery disease. Herein, we present a previously undescribed technique to facilitate safe passage of a guidewire via the inflow limb of the Pruitt-Inahara shunt in the proximal common carotid artery. This technique helps to obviate the risk of causing dissection or intimal damage during retrograde access and carotid stenting in hybrid carotid procedures.

A Spinal Subdural Hematoma Induced by Guidewire-based Lumbar Drainage in a Patient with Ruptured Intracranial Aneurysms

We present a rare case of spinal subdural hematoma induced by guidewire-based lumbar drainage in a subarachnoid hemorrhage patient with a ruptured intracranial aneurysm. Decreased muscle strength and muscle tension of bilateral lower limbs were noted, and an MRI confirmed the spinal subdural hematoma from the sacral to the thoracic segments. The spinal subdural hematoma evacuation and spinal canal decompression were performed by laminectomy. However, the patient did not benefit from the surgery and developed lower limb muscle atrophy. The complication of the spinal subdural hematoma after lumbar drainage is extremely rare; only limited approaches are available for the treatment of spinal hematoma to improve the outcome and avoid severe consequences. Thus, the present case might suggest refraining from use of a guidewire during lumbar drainage for the prevention of spinal subdural hematoma and close observation of the related symptoms and signs for the early detection of spinal hematoma after the procedure. In addition, full decompression can be performed by complete hematoma evacuation and laminectomy of related segments for the treatment of spinal subdural hematoma induced by lumbar drainage.

Transcoronary pacing : Reliability during myocardial ischemia and after implantation of a coronary stent

BACKGROUND

Transcoronary pacing is a useful therapeutic option for the treatment of unheralded bradycardias in the setting of percutaneous coronary interventions (PCI).

OBJECTIVES

In the present study, we investigated the influence of stent implantation and transient myocardial ischemia on the feasibility of transcoronary pacing in a porcine model.

METHODS

7 adult pigs underwent a percutaneous coronary intervention with implantation of a coronary stent under general anaesthesia in an animal catheterization laboratory. Transcoronary pacing was established by using a standard guidewire isolated with an angioplasty balloon positioned in the periphery of the right coronary artery serving as the cathode. As the indifferent anode, a skin patch electrode at the back of the animal was used. The reliability of transcoronary pacing was assessed by measurement of threshold and impedance data and the magnitude of the epicardial electrogram at baseline, after implantation of a coronary stent and finally during myocardial ischemia.

RESULTS

Effective transcoronary pacing could be demonstrated in all cases with the standard unipolar transcoronary pacing setup yielding a low pacing threshold at baseline of 1.3 ± 0.8 V with an impedance of 283 ± 67 Ω. Implantation of a coronary stent did not influence the pacing threshold (1.0 ± 0.4 V) and impedance (262 ± 63 Ω). Acute myocardial ischemia lead to a significant but clinically nonrelevant increase of the pacing threshold to 2.0 ± 0.6 V and a drop in pacing impedance (137 ± 39 Ω).

CONCLUSIONS

Transcoronary pacing in the animal model is not affected by implantation of a coronary stent in the same vessel used for pacing. Despite a significant increase in pacing threshold, the transcoronary pacing approach is reliable in acute myocardial ischemia during a percutaneous coronary intervention.

Right heart catheterization using metallic guidewires and low SAR cardiovascular magnetic resonance fluoroscopy at 1.5 Tesla: first in human experience

BACKGROUND

Cardiovascular magnetic resonance (CMR) fluoroscopy allows for simultaneous measurement of cardiac function, flow and chamber pressure during diagnostic heart catheterization. To date, commercial metallic guidewires were considered contraindicated during CMR fluoroscopy due to concerns over radiofrequency (RF)-induced heating. The inability to use metallic guidewires hampers catheter navigation in patients with challenging anatomy. Here we use low specific absorption rate (SAR) imaging from gradient echo spiral acquisitions and a commercial nitinol guidewire for CMR fluoroscopy right heart catheterization in patients.

METHODS

The low-SAR imaging protocol used a reduced flip angle gradient echo acquisition (10° vs 45°) and a longer repetition time (TR) spiral readout (10 ms vs 2.98 ms). Temperature was measured in vitro in the ASTM 2182 gel phantom and post-mortem animal experiments to ensure freedom from heating with the selected guidewire (150 cm × 0.035″ angled-tip nitinol Terumo Glidewire). Seven patients underwent CMR fluoroscopy catheterization. Time to enter each chamber (superior vena cava, main pulmonary artery, and each branch pulmonary artery) was recorded and device visibility and confidence in catheter and guidewire position were scored on a Likert-type scale.

RESULTS

Negligible heating (< 0.07°C) was observed under all in vitro conditions using this guidewire and imaging approach. In patients, chamber entry was successful in 100% of attempts with a guidewire compared to 94% without a guidewire, with failures to reach the branch pulmonary arteries. Time-to-enter each chamber was similar (p=NS) for  the two approaches. The guidewire imparted useful catheter shaft conspicuity and enabled interactive modification of catheter shaft stiffness, however, the guidewire tip visibility was poor.

CONCLUSIONS

Under specific conditions, trained operators can apply low-SAR imaging and using a specific fully-insulated metallic nitinol guidewire (150 cm × 0.035" Terumo Glidewire) to augment clinical CMR fluoroscopy right heart catheterization.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03152773 , registered May 15, 2017.

VCSim3: a VR simulator for cardiovascular interventions

PURPOSE

Effective and safe performance of cardiovascular interventions requires excellent catheter/guidewire manipulation skills. These skills are currently mainly gained through an apprenticeship on real patients, which may not be safe or cost-effective. Computer simulation offers an alternative for core skills training. However, replicating the physical behaviour of real instruments navigated through blood vessels is a challenging task.

METHODS

We have developed VCSim3-a virtual reality simulator for cardiovascular interventions. The simulator leverages an inextensible Cosserat rod to model virtual catheters and guidewires. Their mechanical properties were optimized with respect to their real counterparts scanned in a silicone phantom using X-ray CT imaging. The instruments are manipulated via a VSP haptic device. Supporting solutions such as fluoroscopic visualization, contrast flow propagation, cardiac motion, balloon inflation, and stent deployment, enable performing a complete angioplasty procedure.

RESULTS

We present detailed results of simulation accuracy of the virtual instruments, along with their computational performance. In addition, the results of a preliminary face and content validation study conveyed on a group of 17 interventional radiologists are given.

CONCLUSIONS

VR simulation of cardiovascular procedure can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. VCSim3 is still a prototype, yet the initial results indicate that it provides promising foundations for further development.

Endoscopic occlusion with silicone spigots for the closure of refractory esophago-bronchiole fistula after esophagectomy

A 65-year-old man with cT1bN0M0 stage I middle thoracic esophageal cancer underwent subtotal esophagectomy and gastric tube reconstruction through the posterior mediastinal route after preoperative carbon-ion radiotherapy and chemotherapy in a clinical trial. Anastomotic leakage occurred, but it spontaneously improved. At six months after the operation, he was rehospitalized with a cough and dysphagia. An esophago-bronchiole fistula and stenosis of the gastric tube were observed. He first underwent stent placement in the gastric tube. Two weeks later, the syringeal epithelium was burned by argon plasma coagulation after stent removal. Endoscopic occlusion was then performed for the fistula with two guidewire-assisted silicone spigots. Two weeks later, he was discharged on an oral diet, and he has not developed recurrence of the fistula or cancer for three years. This is the first report of endoscopic occlusion with a guidewire-assisted silicone spigot through the esophagus.

Robust guidewire tracking under large deformations combining segment-like features (SEGlets)

Robust tracking of interventional tools, such as guidewires and catheters, in X-ray fluoroscopic video sequences has a wide range of clinical applications for endovascular procedures. Thus far, the tracking is usually achieved by finding the optimal displacement of the control points of a spline, which models the guidewire, between consecutive frames. The displacement of the control points is typically driven by a data term and smoothed by a regularization term. In the presence of large deformation and changes in length of the tool, the current tracking methods may fail to recover the guidewire motion. This can occur because of the limitation of the data and regularization terms, and the absence of an explicit solution for coping with elongations of the guidewire. The purpose of this paper is to present an algorithm that can robustly track guidewires under these challenging conditions. The algorithm is based on two main contributions: (a) new robust features termed SEGlets for segment-like features are introduced to overcome the limitations of the current data terms; (b) a tracking formulation based on the generation of tracking hypotheses by organizing the SEGlets in plausible guidewire shapes. The proposed method allows high flexibility of the guidewire between consecutive frames in contrast to the spline model, which can suffer from the limitations of the regularization terms. Furthermore, the technique models elongations of the guidewire which makes it possible for robust tracking under motion. A tool model which is recursively updated by employing a Kalman filter, is also proposed for modelling the regularization term. A detailed evaluation and a comparative study with three state-of-the-art guidewire tracking methods have been performed to demonstrate the potential clinical value of the technique. The proposed method achieves an overall guidewire tracking precision of 2.40 pixels, tip precision of 25.55 pixels, false tracking rate of 5.73%, missing tracking rate of 9.69%, and F₁ score of 0.92. The implementation of the proposed technique and the three tracking methods will be made publicly available as software libraries.

Novel device, a temporary guidewire fixator

A novel device for distal fixation of a guidewire was tested in regards to deployment and retrieval, deposition in the blood stream and force of fixation in a pig model. Eleven pigs were subjected to full anaesthesia and heparinized to active clotting time 250-350 s. Uninterrupted blood flow during 4 h deposition was assessed by angiography and inspected for thrombus deposition upon retrieval. The force of fixation was investigated up to the level of loss of fixation (displacement force). The device was successfully deployed and retrieved in over 40 cases. In one case, an alternative method for bailout retrieval was used. Deposition for 4 h was performed, and uninterrupted blood flow was verified by angiography. No instances of arterial occlusion or thrombosis were detected. The median dislocation force was 7.6 N. No arterial rupture or dissection was detected following the loss of fixation. As a conclusion, the device was considered safe and functional in this animal test model.

Optimal Use of Wire-Assisted Techniques and Precut Sphincterotomy

Various endoscopic techniques have been developed to overcome the difficulties in biliary or pancreatic access during endoscopic retrograde cholangiopancreatography, according to the preference of the endoscopist or the aim of the procedures. In terms of endoscopic methods, guidewire-assisted cannulation is a commonly used and well-known initial cannulation technique, or an alternative in cases of difficult cannulation. In addition, precut sphincterotomy encompasses a range of available rescue techniques, including conventional precut, precut fistulotomy, transpancreatic septotomy, and precut after insertion of pancreatic stent or pancreatic duct guidewire-guided septal precut. We present a literature review of guidewire-assisted cannulation as a primary endoscopic method and the precut technique for the facilitation of selective biliary access.

Prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis by pancreatic duct stenting using a loop-tipped guidewire

AIM: To examine whether it is possible to prevent the occurrence of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis in patients experiencing difficulties with selective biliary duct cannulation by pancreatic duct stenting using a loop-tipped guidewire.

METHODS: Procedure success rate, frequency of unintended insertion of the guidewire into side branches of the pancreatic duct, and incidence of procedural accidents were examined using a loop-tipped guidewire (Group A, 20 patients), and a conventional straight-type guidewire (Group B, 20 patients).

RESULTS: The success rate of the procedure was 100% in both groups. Unintended insertion of the guidewire into a side branch of the pancreatic duct occurred 0.056 ± 0.23 (0-1) times in Group A and 2.3 ± 1.84 (0-5) times in Group B; thus, unintended insertion of the guidewire into a side branch of the pancreatic duct was seen significantly less frequently in Group A. There were no procedural accidents in Group A, whereas pancreatitis occurred in one Group B patient; however, the difference between the two groups was not statistically significant. The serum amylase level after ERCP was 257.15 ± 136.4 (88-628) IU/L in Group A, and 552.05 ± 534.57 (101-2389) IU/L in Group B, showing a significantly lower value in Group A. Hyperamylasemia was found in two patients (10%) in Group A, and nine (45%) in Group B, showing a significantly lower value in Group A.

CONCLUSION: The results suggest that in patients who experience difficulties with biliary cannulation, the use of a loop-tipped guidewire for pancreatic duct stenting may assist with the prevention of post-ERCP pancreatitis, and thereby to a reduction of the risk of post-ERCP pancreatitis or hyperamylasemia.

Language of CTO interventions - Focus on hardware

The knowledge of variety of chronic total occlusion (CTO) hardware and the ability to use them represents the key to success of any CTO interventions. However, the multiplicity of CTO hardware and their physical character and the terminology used by experts create confusion in the mind of an average interventional cardiologist, particularly a beginner in this field. This knowledge is available but is scattered. We aim to classify and compare the currently used devices based on their properties focusing on how physical character of each device can be utilized in a specific situation, thus clarifying and simplifying the technical discourse.