Comparing Blind and Ultrasound-Guided Retrobulbar Nerve Blocks in Equine Cadavers: The Training Effect

In standing ophthalmic surgery in horses, a retrobulbar nerve block (RNB) is often placed blindly for anesthesia and akinesia. The ultrasound (US)-guided RNB may have fewer complications, but the two techniques have only been compared once in equine cadavers. This study compares the techniques for success and complication rates and analyzes the effect of training on US guidance. Twenty-two equine cadavers were divided into three groups: blind RNBs were performed bilaterally in eight cadavers, US-guided RNBs were performed bilaterally in seven cadavers, and after US-guided training, blind RNBs were performed bilaterally in seven cadavers. All RNBs were performed by the same two inexperienced operators, and a combination of contrast medium (CM; 1.25 mL) and methylene blue dye (1.25 mL) were injected (2.5 mL total volume). Needle positioning in the periorbita and the distance of the CM to the optic foramen were assessed using computerized tomography (CT). Dye spreading was evaluated by dissection. In group 1, 37.5% of the injections were in the optimal central position in the periorbita; in group 2, 75% and in group 3, 71.4%. There was no significant difference between the groups regarding needle position (groups 1 and 2 p = 0.056; groups 1 and 3 p = 0.069, groups 2 and 3 p = 0.8). The mean CM distribution distance was not significantly different between all groups. Group 1 had 18.75% intraocular injections versus 0% in group 2 and 7.1% in group 3 (not significant). US guidance showed no significant increases in accuracy nor decreases in complications. However, the effects on accuracy showed a trend towards significant improvement, and larger scale follow-up studies might show significant training effects on US guidance.

Towards a First-Person Perspective Mixed Reality Guidance System for Needle Interventions

While ultrasound (US) guidance has been used during central venous catheterization to reduce complications, including the puncturing of arteries, the rate of such problems remains non-negligible. To further reduce complication rates, mixed-reality systems have been proposed as part of the user interface for such procedures. We demonstrate the use of a surgical navigation system that renders a calibrated US image, and the needle and its trajectory, in a common frame of reference. We compare the effectiveness of this system, whereby images are rendered on a planar monitor and within a head-mounted display (HMD), to the standard-of-care US-only approach, via a phantom-based user study that recruited 31 expert clinicians and 20 medical students. These users performed needle-insertions into a phantom under the three modes of visualization. The success rates were significantly improved under HMD-guidance as compared to US-guidance, for both expert clinicians (94% vs. 70%) and medical students (70% vs. 25%). Users more consistently positioned their needle closer to the center of the vessel’s lumen under HMD-guidance compared to US-guidance. The performance of the clinicians when interacting with this monitor system was comparable to using US-only guidance, with no significant difference being observed across any metrics. The results suggest that the use of an HMD to align the clinician’s visual and motor fields promotes successful needle guidance, highlighting the importance of continued HMD-guidance research.

Axillary vein catheterization using ultrasound guidance: A prospective randomized cross-over controlled simulation comparing standard ultrasound and new needle-pilot device

Background: Real-time ultrasound (US) guidance facilitates central venous catheterization in intensive care unit (ICU). New magnetic needle-pilot devices could improve efficiency and safety of central venous catheterization. This simulation trial was aimed at comparing venipuncture with a new needle-pilot device to conventional US technique. Methods: In a prospective, randomized, simulation trial, 51 ICU physicians and residents cannulated the right axillary vein of a human torso mannequin with standard US guidance and with a needle-pilot system, in a randomized order. The primary outcome was the time from skin puncture to successful venous cannulation. The secondary outcomes were the number of skin punctures, the number of posterior wall puncture of the axillary vein, the number of arterial punctures, the number of needle redirections, the failure rate, and the operator comfort. Results: Time to successful cannulation was shorter with needle-pilot US-guided technique (22 s (interquartile range (IQR) = 16–42) vs 25 s (IQR = 19–128); median of difference (MOD) = −9 s (95%-confidence interval (CI) −5, −22), p < 0.001). The rates of skin punctures, posterior wall puncture of axillary vein, and needle redirections were also lower ( p < 0.01). Comfort was higher in needle-pilot US-guided group on a 11-points numeric scale (8 (IQR = 8–9) vs 6 (IQR = 6–8), p < 0.001). Conclusions: In a simulation model, US-guided axillary vein catheterization with a needle-pilot device was associated with a shorter time of successful cannulation and a decrease in numbers of skin punctures and complications. The results plea for investigating clinical performance of this new device.

Complication rates of percutaneous brachial artery puncture: effect of live ultrasound guidance

Purpose The current literature on the use of brachial artery access is controversial. Some studies found increased puncture site complications. Others found no higher complication rates than in patients with femoral or radial access. The purpose of this study was to determine the impact of ultrasound (US)-guidance on access site complications. Materials and methods This is a single-center retrospective study of all consecutive patients with brachial arterial access for interventional procedures. Complications were classified into minor complications (conservative treatment only) and major complications (requiring surgical intervention). The brachial artery was cannulated in the antecubital fossa under US-guidance. After the intervention, manual compression or closure devices, both followed by a compression bandage for 3 h, either achieved hemostasis. Results Seventy-five procedures in seventy-one patients were performed in the study period using brachial access. Access was successful in all cases (100%). Procedures in different vascular territories were performed: neurovascular (10/13.5%), upper extremity (32/43.2%), visceral (20/27.0%), and lower extremity (12/16.3%). Sheath size ranged from 3.2F to 8F (mean: 5F). Closure devices were used in 17 cases (22.7%). In total, six complications were observed (8.0%), four minor complications (5.3%, mostly puncture site hematomas), and two major complications, that needed surgical treatment (2.7%). No brachial artery thrombosis or upper extremity ischemia occurred. Conclusion Exclusive use of US-guidance resulted in a low risk of brachial artery access site complications in our study compared to the literature. US-guidance has been proven to reduce the risk of access site complications in several studies in femoral access. In addition, brachial artery access yields a high technical success rate and requires no additional injection of spasmolytic medication. Sheath size was the single significant predictor for complications.

Radiation-Free Transabdominal Ultrasound-Guided Endoscopic Biliary Stenting in Pregnant Women with Choledocholithiasis

Background: Hepatobiliary disorders are common problems during pregnancy, causing significant morbidity and mortality in both mother and fetus. Biliary pancreatitis and cholangitis are common sequelae that warrant urgent endoscopic interventions. However, fetal radiation exposure is a major concern during endoscopic retrograde cholangiopancreatography (ERCP). Fetal malformation, preterm labor, and intrauterine fetal death are the recognized complications of ERCP. Objectives: To evaluate the application of transabdominal ultrasound (US) guidance in endoscopic biliary stenting as a substitute for fluoroscopy and contrast injection. Methods: In this study, we reviewed the data of ten pregnant patients, who had undergone endoscopic biliary stenting under US guidance without fluoroscopy between January 2018 and October 2020. An abdominal US examination was performed to confirm that the guide wire and the stent were placed inside the common bile duct (CBD) without fluoroscopy. The CBD clearance was postponed until after delivery. Results: The mean gestational age was 12 weeks (range: 5 - 33 weeks), and the mean maternal age was 23 years (range: 19 - 33 years). All procedures were performed successfully, with biochemical and clinical improvements after endoscopy. In none of the patients, maternal or fetal complications were reported after endoscopy or at birth. Also, no cases of post-endoscopic pancreatitis were documented. Conclusions: Based on the present findings, abdominal US guidance in endoscopic biliary stenting can be a safe and effective approach.

Complication Rates of Percutaneous Brachial Artery Puncture: Effect of Live Ultrasound Guidance

PurposeThe current literature on the use of brachial artery access is controversial. Some studies found increased puncture site complications. Others found no higher complication rates than in patients with femoral or radial access. The purpose of this study was to determine the impact of ultrasound (US)-guidance on access site complications.Materials and MethodsThis is a single-center retrospective study of all consecutive patients with brachial arterial access for interventional procedures. Complications were classified into minor complications (conservative treatment only) and major complications (requiring surgical intervention). The brachial artery was cannulated in the antecubital fossa under US-guidance. After the intervention, manual compression or closure devices, both followed by a compression bandage for 3 hours, either achieved hemostasis.Results75 procedures in 71 patients were performed in the study period using brachial access. Access was successful in all cases (100%). Procedures in different vascular territories were performed: neurovascular (11/14.7%), upper extremity (36/48%), visceral (20/26.7%), and lower extremity (12/16%). Sheath size ranged from 3.2F to 8F (mean: 5F). Closure devices were used in 17 cases (22.7%). In total, six complications were observed (8.0%), four minor complications (5.3%, mostly puncture site hematomas), and two major complications, that needed surgical treatment (2.7%). No brachial artery thrombosis or upper extremity ischemia occurred.ConclusionExclusive use of US-guidance resulted in a low risk of brachial artery access site complications in our study compared to the literature. US-guidance has been proven to reduce the risk of access site complications in several studies in femoral access. In addition, brachial artery access yields a high technical success rate and requires no additional injection of spasmolytic medication. Sheath size was the single significant predictor for complications.

Deconstructing Dante: How things fall apart in the Paradiso

Much recent commentary on Dante’s Commedia focuses on Dante’s truth claims in the poem. Indeed, Teodolinda Barolini has proposed that “the fundamental question for all readers of Dante’s poem” is “How are we to respond to the poet’s insistence that he is telling us the truth?” I propose that the poem itself gives us guidance as to the seriousness of its claims to literal truth. It does so by actively deconstructing its own meaning at critical junctures. I look at several such moments of deconstruction, but I argue that the first few cantos of the Paradiso in particular provide a reflection on the difference between reality and fiction. Early in the Paradiso, Dante draws attention to the metaphoric nature of his poem and reminds his reader, through his character’s own actions, that metaphor is not reality. In this way, Dante implies that we should not take the narrative particulars of his poem too literally but should treat metaphor as metaphor rather than as mimesis.

Ulnar Neuropathy at the Elbow: From Ultrasound Scanning to Treatment

Ulnar neuropathy at the elbow (UNE) is commonly encountered in clinical practice. It results from either static or dynamic compression of the ulnar nerve. While the retroepicondylar groove and its surrounding structures are quite superficial, the use of ultrasound (US) imaging is associated with the following advantages: (1) an excellent spatial resolution allows a detailed morphological assessment of the ulnar nerve and adjacent structures, (2) dynamic imaging represents the gold standard for assessing the ulnar nerve stability in the retroepicondylar groove during flexion/extension, and (3) US guidance bears the capability of increasing the accuracy and safety of injections. This review aims to illustrate the ulnar nerve's detailed anatomy at the elbow using cadaveric images to understand better both static and dynamic imaging of the ulnar nerve around the elbow. Pathologies covering ulnar nerve instability, idiopathic cubital tunnel syndrome, space-occupying lesions (e.g., ganglion, heterotopic ossification, aberrant veins, and anconeus epitrochlearis muscle) are presented. Additionally, the authors also exemplify the scientific evidence from the literature supporting the proposition that US guidance is beneficial in injection therapy of UNE. The non-surgical management description covers activity modifications, splinting, neuromobilization/gliding exercise, and physical agents. In the operative treatment description, an emphasis is put on two commonly used approaches—in situ decompression and anterior transpositions.

Real-time ultrasound-guided low thoracic epidural catheter placement: technical consideration and fluoroscopic evaluation

Background and objectiveThoracic epidural analgesia can significantly reduce acute postoperative pain. However, thoracic epidural catheter placement is challenging. Although real-time ultrasound (US)-guided thoracic epidural catheter placement has been recently introduced, data regarding the accuracy and technical description are limited. Therefore, this prospective observational study aimed to assess the success rate and describe the technical considerations of real-time US-guided low thoracic epidural catheter placement.Methods38 patients in the prone position were prospectively studied. After the target interlaminar space between T9 and T12 was identified, the needle was advanced under real-time US guidance and was stopped just short of the posterior complex. Further advancement of the needle was accomplished without US guidance using loss-of-resistance techniques to normal saline until the epidural space was accessed. Procedure-related variables such as time to mark space, needling time, number of needle passes, number of skin punctures, and the first-pass success rate were measured. The primary outcome was the success rate of real-time US-guided thoracic epidural catheter placement, which was evaluated using fluoroscopy. In addition, the position of the catheter, contrast dispersion, and complications were evaluated.ResultsThis study included 38 patients. The T10–T11 interlaminar space was the most location for epidural access. During the procedure, the mean time for marking the overlying skin for the procedure was 49.5±13.8 s and the median needling time was 49 s. The median number of needle passes was 1.0 (1.0–1.0). All patients underwent one skin puncture for the procedure. The first-pass and second-pass success rates were 76.3% and 18.4%, respectively. Fluoroscopic evaluation revealed that the catheter tips were all positioned in the epidural space and were usually located between T9 and T10 (84.2%). The cranial and caudal contrast dispersion were observed up to 5.4±1.6 and 2.6±1.0 vertebral body levels, respectively. No procedure-related complications occurred.ConclusionReal-time US guidance appears to be a feasible option for facilitating thoracic epidural insertion. Whether or not this technique improves the procedural success and quality compared with landmark-based techniques will require additional study.Trial registration numberNCT03890640.

Long-term Clinical Results of Carpal Tunnel Release Using Ultrasound Guidance

Background: The purpose of this study was to determine the long-term safety and efficacy of carpal tunnel release (CTR) using ultrasound guidance in a group of patients treated by a single physician. Methods: The study group consisted of 76 consecutive CTRs performed on 47 patients between June 2017 and April 2019 for whom 1-year follow-up was available. All procedures were performed by the same operator using a single CTR technique. Outcomes included complications; Boston Carpal Tunnel Questionnaire symptom severity (BCTQ-SSS) and functional status (BCTQ-FSS) scores; Quick Disabilities of the Arm, Shoulder, and Hand (QDASH) scores; and a 5-point global satisfaction score (4 = satisfied, 5 = very satisfied). Results: The 47 patients included 27 females and 20 males (ages 31-91 years). Twenty-five patients (50 hands) had simultaneous bilateral CTRs, 4 patients (8 hands) had staged bilateral CTRs, and 18 patients had unilateral CTRs. No complications occurred. Statistically and clinically significant reductions in BCTQ-SSS, BCTQ-FSS, and QDASH scores occurred by 1 to 2 weeks post-CTR and persisted at 1-year (mean 1-year changes vs. pre-CTR -2.11, -1.70, and -44.99, respectively; P < .001 for all). The mean global satisfaction score at 1-year was 4.63. Conclusions: CTR using ultrasound (US) guidance is a safe and effective procedure that produces statistically and clinically significant improvements within 1 to 2 weeks postprocedure that persist to 1 year. Furthermore, simultaneous bilateral CTRs using US guidance are feasible and may be advantageous for patients who are candidates for bilateral CTR.