Advancement Of Catheter Research Articles

Pediatric Arterial Interventions

The spectrum of pediatric vascular pathology differs from the adult population and it varies greatly to include congenital and acquired disorders. Although catheter-directed angiography remains the gold standard, most vascular conditions in the child can be adequately diagnosed with magnetic resonance angiography, computed tomographic angiography, or duplex/Doppler ultrasonography with only a few exceptions, such as intrarenal arterial stenosis, small vessel vasculitides, and visceral vascular malformations. The advancement of catheter and wire technology has made it increasingly possible for complex arterial interventions to be performed in children, including embolization, angioplasty with stent insertion, thrombolysis, and endovascular neurological procedures. More angiographic procedures are being performed with the aim of also being therapeutic. Special considerations in children include the use of appropriate equipment and adequate dosing of contrast and of the various medications used during angiography, particularly in patients less than 15 kg in weight. This article will focus on the management of renovascular hypertension, liver transplant hepatic arterial intervention, and the use of carbon dioxide gas as a contrast agent in the child.

Azygous Continuation of Inferior Vena Cava

![Figure][1] A 70-year-old man presented for typical atrial flutter ablation. Right femoral venous access was obtained but there was difficulty in catheter advancement into the right atrium and the procedure was abandoned. The patient was sent for a cardiac computed tomographic angiography.

The threshold elicited motor response via an in situ femoral nerve catheter predicts analgesia following total knee replacement

BackgroundContinuous femoral nerve blocks are a part of the multimodal perioperative anesthetic regimen following total knee replacement. Elicitation of a quadriceps muscle contraction (QC) at placement is desirable. We prospectively evaluated the relationship between elicited motor response and threshold current with block success in situ femoral nerve catheters after total knee replacement.MethodsAfter Institutional Review Board approval and written informed consent, 100 adults aged ≥18 years, undergoing total knee replacement were studied. The threshold current for an elicited motor response (QC or sartorius muscle contraction [SC]) was recorded during needle insertion, after femoral nerve catheter advancement, and prior to local anesthetic administration on the first postoperative day. Patients were assessed for pinprick sensory anesthesia of the femoral nerve distribution by an observer unaware of the current threshold or evoked motor response at 5-minute intervals for 30 minutes. A successful block was considered a lack of pinprick sensation within 30 minutes.ResultsNinety patients completed the study. A QC was obtained at needle insertion in 89 and maintained following catheter advancement in 77 subjects. Prior to drug administration a QC was obtained in 66 patients, 13 demonstrated an SC, and 11 had no motor response. QC prior to drug administration had a sensitivity of 0.85 (95% confidence intervals [CI]: 0.75 to 0.92) and a specificity of 0.55 (95% CI: 0.37 to 0.72) for complete femoral nerve block. The specificity of a QC prior to drug administration was greater than at catheter placement (P = 0.006). Compared to the threshold current at catheter placement, 27 patients had a decrease, 60 had an increase, and 3 exhibited no change in the threshold current prior to drug administration (P < 0.01). The median interquartile range (IQR) threshold current in patients that achieved a complete block was 0.56 (0.29 to 0.80) mA compared with 1.1 mA (0.41 to 2.75) mA for incomplete blocks (P < 0.01). The area under the receiver operator characteristics curve for current threshold prior to local anesthetic administration (0.74) was greater than at catheter placement (0.45) (P < 0.001). The intersection of sensitivity and specificity for the minimal threshold current prior to local anesthetic injection was 0.84 mA.ConclusionThe elicited motor response and current threshold from a stimulating femoral catheter measured prior to local anesthetic injection is an important determinant of the success of femoral nerve block following bolus administration.

Arterial imaging in patients with lower extremity ischemia and diabetes mellitus

Precise, comprehensive imaging of the arterial circulation is the cornerstone of successful revascularization of the ischemic extremity in patients with diabetes mellitus. Arterial imaging is challenging in these patients because the disease is often multisegmental with a predilection for the distal tibial and peroneal arteries. Occlusive lesions and the arterial wall itself are often calcified and patients presenting with ischemic complications frequently have underlying renal insufficiency. Intra-arterial digital subtraction angiography (DSA), contrast enhanced magnetic resonance angiography (MRA), and more recently, computerized tomographic angiography (CTA) have been used as imaging modalities in lower extremity ischemia. Each has specific advantages and shortcomings in this patient population, which will be summarized and contrasted in this review. DSA is an invasive technique most often performed from a femoral arterial puncture and requires the injection of arterial contrast, which can occasionally cause allergic reactions. In patients with pre-existing renal insufficiency, contrast infusion can result in worsening renal failure; although usually self-limited, it may occasionally require hemodialysis, especially in patients with diabetes. However, DSA provides the highest degree of spatial resolution and image quality. It is also the only modality in which the diagnosis and treatment of arterial disease can be performed simultaneously. MRA is noninvasive, and when enhanced with gadolinium contrast injection provides arterial images of comparable quality to DSA and in some circumstances may uncover distal arterial targets not visualized on DSA. However, spatial resolution is inferior to DSA and erroneous interpretations due to acquisition artifacts are common. Specialized equipment and imaging techniques are necessary to minimize their occurrence in the distal lower extremity. In addition, due to the risk of inducing nephrogenic systemic fibrosis, gadolinium-enhanced MRA cannot be used in patients with renal insufficiency. CTA is noninvasive and rapidly performed, with better spatial resolution than MRA, but requires the largest volume of contrast infusion, exposes patients to high-doses of radiation, and is subject to interpretive error due to reconstruction artifacts especially in heavily calcified arteries, limiting its usefulness in many patients with diabetes. For patients in whom the planned intervention is a surgical bypass, DSA and MRA will provide high quality images of the lower extremity arterial anatomy. For patients in whom a catheter-based intervention is the likely treatment, a diagnostic DSA immediately followed by a catheter-based treatment in the same procedure is the preferred approach. In patients with pre-existing renal dysfunction, in which gadolinium-enhanced MRA is contraindicated, DSA or CTA can be performed. However, patients should have an infusion of intravenous normal saline solution or sodium bicarbonate before the procedure to reduce the incidence of contrast-induced nephropathy.

Examining the causes of ablation failure in the Wolff-Parkinson-White syndrome

the His-bundle at a midseptal or anteroseptal location, increasing the risk of inadvertent complete atrioventricular block. The use of a long sheath may facilitate catheter stability if the accessory pathway is located along the right midseptal or anteroseptal region. In these cases, we favour advancement of the ablation catheter from the right jugular vein, since this site of access is in direct alignment with the location of the accessory pathway. Stable wall contact is accomplished by counterclockwise torque of the catheter. In addition, we found that an anteroseptal pathway may be successfully ablated from the non-coronary cusp. 7 Some operators prefer to use cryothermia. Our laboratory routinely uses RF current when ablating para-Hisian pathways. A His potential is practically always recorded at the earliest site of accessory pathway activation. However, the His bundle is protected by fibrous tissue, whereas the accessory pathway is superficially located, making damage to the His bundle very unlikely with the judicious use of RF energy. An epicardial accessory pathway location may not be amenable to a routine endocardial approach. If a posteroseptal accessory pathway is suspected, coronary sinus angiography will facilitate proper anatomic delineation and catheter ablation. In 21% of patients with a suspected posteroseptal or left posterior accessory pathway, coronary sinus angiography demonstrated a diverticulum originating from the middle cardiac vein, coronary sinus, or both. 8 Ablation is performed by advancing the ablation catheter into the coronary sinus, targeting the neck of the diverticulum. In rare cases, an epicardial accessory pathway may mimic electrocardiographic criteria of a manifest right anteroseptal accessory pathway. Clues to the correct diagnosis during endocardial

Strategies to prevent intravascular placement of epidural catheter

To the Editor: We read with great interest the article by Kundra et al. [1] regarding resistance to the insertion of epidural catheter and intravascular placement. It is interesting to note that resistance was felt in a large number of patients in the study (83 out of 120; 69.12%) at insertion length of 2.5 cm during the epidural catheter placement. However, only 7.5% of these patients had intravascular placement, which suggests that this resistance felt by researchers may not be necessarily due to blood vessels. It is also not clear from the article for the reasons for this resistance. In view of this, it is difficult to say that the advancement of catheter more than 2.5 cm, despite resistance may cause intravascular placement, as suggested by researchers. There are at least three studies that demonstrate safe and successful placement of epidural catheter up to 5 cm in length in laboring patients [2]. Though the optimal insertion length of epidural catheter is not conclusive, there should be a balance between successful epidural analgesia and strategies taken to minimize complications [3]. We would also like to point out that there are at least five strategies to prevent intravascular placement of epidural catheter. As per the previous studies, these strategies are; fluid injection before catheter insertion [4], lateral position during the procedure, use of single orifice, wireembedded catheters [5], and epidural insertion length not more than 6 cm [2]. Recent systematic review by Mhyre et al. [5] published in April 2009 has discussed these strategies in detail for the prevention of intravascular placement of epidural catheter in laboring patients. Though this systematic review did not recommend one particular strategy over another to prevent intravascular placement, more studies support lateral position during the procedure and fluid injection before catheter insertion. Also, there is little evidence to support the practice of a paramedian versus midline approach or using a smaller epidural needle. So it is advisable to use multiple strategies to prevent intravascular placement of the catheter rather than relying on single strategy.

Usefulness of CT-Guided Percutaneous Catheter Drainage Using a Modified Version of the Seldinger Technique for the Treatment of Intra-abdominal Small Abscess and Poorly Depicted Fluid Collection on Sonogram

Purpose: To evaluate the usefulness of CT-guided percutaneous catheter drainage (PCD) using a modified version of the Seldinger technique for deep-seated, small abscesses and poorly depicted fluid collection on abdominal sonogram. Materials and Methods: Fifty-nine cases of CT-guided PCD were performed on 56 patients. Four techniques were applied to secure safe access routes, which include scan postural change, angulation of the gantry, traversal of organs, and using a dissecting needle which can push the intervening bowel. Three landmarks (depth of the front and back wall of the fluid collection and the end point of catheter advancement over the guide wire) were indicated on the drainage catheter for extracorporeal direct observation of moving distance and location of the catheter during the insertion process. The technical success rate, clinical outcome, complications, and instrumental impairments were reviewed. Results: The technical success rate was 100% (59/59), and no grave complications occurred. Four cases (7%) of crooked guide wire insertion were noted. The clinical outcome revealed a 95% (56/59) successful treatment rate and a 5% (3/59) failed treatment rate, which was caused by undissolved hematoma (1/59) and fistula (2/59). Conclusion: The results of this study suggest that CT-guided PCD using a modified version of the Seldinger technique for deep-seated, small abscesses and poorly depicted fluid collections on an abdominal sonogram is useful in terms of accuracy and safety.

Use of the Seldinger Type Movement Over a J-Shaped Stylet for Left Ventricular Vent Insertion

Access through the right superior pulmonary vein is a commonly used route for left ventricular vent insertion. Complex reshaping of the stylet and vent into a certain position or external guidance do not guarantee successful placement. In this article we describe a modified technique where the stylet sets up the position to allow consistent atraumatic advancement of the catheter across the mitral valve.

Peritoneal Dialysis Catheter Insertion by Interventional Nephrologists

Peritoneal dialysis (PD) catheter placement is performed by surgeons, interventional radiologists, and interventional nephrologists. Catheter insertion is accomplished through various methods including open surgical technique and laparoscopic, peritoneoscopic, and fluoroscopic guidance. Complication rates and catheter survival can vary based on the insertion technique used. Recently, nephrologists have made significant advances in the area of peritoneal dialysis catheter design and placement. Current data suggest that nephrologists are increasingly placing PD catheters using peritoneoscopic and fluoroscopic technique. This review focuses on peritoneoscopic and fluoroscopic insertion and highlights the advantages of catheter insertion by nephrologists.

Robotic magnetic navigation for ablation of human arrhythmias: Initial experience

Magnetic navigation system (MNS) (Niobe, Stereotaxis, Saint-Louis, Missouri, USA) allows remote control of a radiofrequency ablation catheter using a steerable magnetic field and a catheter advancement system. We report our initial experience of ablation of human arrhythmias using the MNS. Eighty-four patients (mean age 54+/-17years; 39 women) had an electrophysiologic study followed by ablation with the MNS using non-irrigated 4, 8 and 3.5mm-tip catheters with three distal magnets. All patients were symptomatic, with commonly-accepted indications for ablation: atrioventricular nodal re-entrant tachycardia (AVNRT; n=37); typical atrial flutter (n=15); accessory pathway (n=12); atypical atrial flutter (n=7); ventricular tachycardia (n=7); atrial tachycardia (n=3); paroxysmal atrial fibrillation (n=3). Electroanatomical mapping was used for atrial flutter, atrial fibrillation, atrial tachycardia and ventricular tachycardia procedures (29 patients, 34%). Ablation was performed successfully in 69 (82%) patients. In 15 patients (18%), MNS technique was unsuccessful: seven typical atrial flutters, four accessory pathways, two left atrial flutters after atrial fibrillation ablation, one ventricular tachycardia and one AVNRT; in all these cases except one typical atrial flutter and two left atrial flutters, success was obtained by switching to the manual technique by means of an irrigated catheter. Total fluoroscopy time was 14+/-11minutes; operator exposure fluoroscopy time was 1.5+/-0.6minutes; procedure time was 169+/-72minutes. MNS ablation is a feasible treatment for various human arrhythmias, with a high success rate. Mapping with a magnetic catheter is safe. However, magnetic ablation of typical atrial flutter remains challenging, probably because of insufficient pressure for cavotricuspid isthmus ablation.

Small Animal Models of Heart Failure

Received June 23, 2008; accepted January 20, 2009. The study of heart failure requires viable animal models whereby chronic changes in myocardial structure and function can evolve and the progression of heart failure and left ventricular (LV) dysfunction can be quantified. During the past 40 years, basic and translational scientists have used small animal models to explore the pathophysiology of heart failure and to develop novel therapies that might slow the progression of this prevalent and fatal disease. The purpose of this review is to describe commonly used heart failure models in rodents and to cite examples of how these models have been used to evaluate novel therapies for the treatment of heart failure. Heart failure models were originally developed in rats because of numerous potential advantages inherent in a small animal model (see Table 1). Housing and maintenance costs for rats are much lower than for large animals, thus reducing costs and increasing the number of animals included in a given study to improve the statistical power. Moreover, more recent technological advances in echocardiography, MRI, and micromanometer conductance catheters have greatly streamlined the assessment of cardiac function in rodents, removing a significant barrier to their use in heart failure research. The development of suitable expertise to perform open-chest surgical procedures and invasive hemodynamic assessments in rats is far easier compared with that required for mice. Additionally, investigators are able to perform a greater number of postmortem histological or molecular biological analyses given the approximately 10-fold greater myocardial mass of rats compared with mice. For these reasons, the rat models detailed below have been the most widely and successfully used heart failure models in basic and translational research. View this table: Table. Commonly Used Rodent Heart Failure Models Myocardial infarctions (MIs) in rats were originally induced by the sequential administration of subcutaneous isoproterenol …

An unusual complication of endotracheal tube suctioning

1. Ensure that the suction catheter size is appropriate in relation to the lumen of the ETT prior to insertion. 2. Consider lubricant or silicone spray when a larger diameter suction catheter is considered for suctioning. 3. Consider the use of a smaller diameter suction catheter. 4. Avoid manipulation (back and forth advancement and withdrawal) of the suction catheter within the lumen of the ETT. 5. When using a larger diameter suction catheter, completely remove the suction catheter from the ETT and re-insert if needed for a subsequent pass.

Vascular changes after cardiac surgery: role of NOS, COX, kinases, and growth factors

Cardiovascular disease remains the leading cause of mortality in the industrialized world. Despite advances in pharmacotherapy and catheter based interventions, coronary artery bypass grafting remains an essential therapeutic modality. The majority of coronary artery bypass operations, as well as other cardiac surgical procedures require the use of ischemic cardioplegic arrest and cardiopulmonary bypass, both of which result in iatrogenic injury to the vasculature and microcirculation. This injury can manifest as impaired vasorelaxation or vasoconstriction, depending upon the organ system involved, resulting in impaired tissue perfusion and the development of edema. Key to this dysfunction are changes in the following: nitric oxide signaling secondary to changes in eNOS and iNOS expression and activity, cyclooxygenase function with increases in pro-inflammatory COX-2 activity, alterations in Protein Kinase C and Mitogen Activated Protein Kinase signaling, and an increase in Vascular Endothelial Growth Factor expression increasing vascular permeability and dilatation. This review discusses our current understanding of cardioplegia and cardiopulmonary bypass induced changes in the vasculature, and therapeutic interventions aimed at modulating the altered signaling pathways.

Knotting of a guidewire during internal jugular vein catheterization in an infant: A case report.

Central venous catheterization has been frequently used in pediatric patients in wide variety of conditions. Several authors have described about various complication of central venous catheterization in pediatric patients and reported complication rates of 3% to 6%. Knotting of guidewire as a complication of central venous catheterization has been reported in adult patients, but knotting of guidewire has not been reported in infants. Therefore we report an infant who experienced a knotting of guidewire during internal jugular vein catheterization which was successfully removed without any adverse events. We suggest that knot formation is possible in infants and there should be a high suspicion if resistance is felt at the time of catheter advancement.

Atherosclerotic Peripheral Vascular Disease Symposium II

Percutaneous intervention for peripheral artery disease has evolved from balloon angioplasty for simple focal lesions to multimodality techniques that enable treatment of severe arterial insufficiency. This technological expansion comes without a standard approach or algorithm, which makes the decision-making process more subjective than objective. Nevertheless, clinical tools are available that can have a favorable effect on patient care, and these promote usage. So, when are standard endovascular techniques (such as balloon and stents) good enough, and when are the latest advances (eg, atherectomy, drug-eluting stents) more appropriate? This section will address these questions for acute limb ischemia (ALI) and chronic critical limb ischemia (CLI). It will also delineate the problem of restenosis, particularly of the superficial femoral artery (SFA), and describe treatment alternatives. The discussion will review the role of drug-eluting stents, atherectomy devices, reentry catheters, and brachytherapy, as well as their potential complications and appropriate remedies. Treatment algorithms for aortoiliac and infrainguinal disease are provided in Figures 1 through 3⇓⇓. Figure 1. Treatment algorithm for acute lower-limb ischemia. *Short infusion of thrombolytic therapy proximal to occlusion can be used to facilitate wire traversal. Figure 2. Simplified treatment algorithm for symptomatic aortoiliac disease in patients deemed candidates for revascularization. In patients with multilevel disease, the aortoiliac segment should be addressed first. TASC indicates TransAtlantic Inter-Society Consensus; AI, aortoiliac; PTA, percutaneous transluminal angioplasty; PE, physical examination; ABI, ankle-brachial index; and U/S, ultrasound. Figure 3. Simplified treatment algorithm for symptomatic infrainguinal peripheral arterial disease, assuming concomitant aortoiliac disease has been treated and the patient is an acceptable candidate for revascularization. *Alternative therapies to PTA include cryotherapy, atherectomy (directional, rotational, ablative), and cutting balloon. †Alternative stent options include stent (graft, balloon expanding, and self expanding) and drug-eluting stent. PTA indicates percutaneous transluminal angioplasty; TASC, TransAtlantic Inter-Society Consensus; PE, physical examination; …

Audit of motor weakness and premature catheter dislodgement after epidural analgesia in major abdominal surgery

In a quality improvement audit on epidural analgesia in 300 patients after major abdominal surgery, we identified postoperative lower leg weakness and premature catheter dislodgement as the most frequent causes of premature discontinuation of postoperative epidural infusion. Lower limb motor weakness occurred in more than half of the patients with lumbar epidural analgesia. In a second period monitoring 177 patients, lumbar catheter insertion was abandoned in favour of exclusive thoracic placement for epidural catheters. Additionally, to prevent outward movement, the catheters were inserted deeper into the epidural space (mean (SD) 5.2 (1.5) cm in Period Two vs 4.6 (1.3) cm in Period One). Lower leg motor weakness declined from 14.7% to 5.1% (odds ratio 0.35; 95% confidence interval 0.16-0.74) between the two periods. Similarly, the frequency of premature catheter dislodgement was reduced from 14.5% to 5.7% (odds ratio 0.35; 95% confidence interval 0.17-0.72). With a stepwise logistic regression model we demonstrated that the odds of premature catheter dislodgement was reduced by 43% for each centimetre of additional catheter advancement in Period Two. We conclude that careful audit of specific complications can usefully guide changes in practice that improve success of epidural analgesia regimens.

High‐frequency vibration for the recanalization of guidewire refractory chronic total coronary occlusions

Recanalization of coronary chronic total occlusions (CTOs) remains a clinical challenge, particularly when standard guidewire attempts fail. We sought to determine the safety and efficacy of a novel method that used high-frequency (20 kHz) vibration to fragment occlusive fibrous tissue and facilitate guidewire crossing into the distal vessel. A total of 125 patients with CTO, who failed at attempts of conventional guidewire recanalization after more than 5 min of fluoroscopy time, were enrolled in the study. The primary efficacy endpoint was the advancement of the CROSSER catheter through the occlusion and attainment of coronary guidewire positioning in the distal coronary lumen. The primary safety endpoint was the occurrence of death, myocardial infarction, clinical perforation, or target vessel revascularization within the first 30 days. The average fluoroscopy time while delivering the CROSSER catheter was 12.4 min. CROSSER-assisted guidewire recanalization was achieved in 76 (60.8%) procedures and a final diameter stenosis <50% was obtained in 68 (54.4%) of cases. Major adverse events occurred in 11 (8.8%) patients, lower than the predefined objective performance criteria. Angina frequency and quality of life were improved in patients with successful guidewire recanalization. We conclude that high-frequency vibration using the CROSSER catheter is a safe and effective therapy for patients with CTO, which are refractory to standard guidewire recanalization.

Long-Axis Ultrasound Imaging of the Nerves and Advancement of Perineural Catheters Under Direct Vision: A Preliminary Report of Four Cases

Ultrasound allows visualization of in plane needle insertion toward a nerve and the perineural spread of local anesthetic (LA) solution. However, advancement and final positioning of perineural catheters is difficult to visualize. We assessed the feasibility of long axis nerve scans for controlling perineural catheter placement. Four orthopedic patients scheduled for continuous peripheral nerve blocks (interscalene, femoral, midfemoral sciatic, and popliteal sciatic), had perineural catheters inserted under ultrasound guidance. After obtaining adequate short axis images of the target nerves, the high frequency linear transducer was rotated 90 degrees to obtain long axis views. An 18-gauge epidural Tuohy needle was inserted tangentially to the nerve and the correct tip position was confirmed visually by small volume injections of LA. A rigid epidural catheter was inserted under the transducer's long plane and advanced into the desired perineural position. LA was then injected through the catheter and the spread was confirmed both on long axis and short axis scans. The catheters were captured on the long axis scans in all 4 patients, both exiting the needle tip, and during further advancement. They remained in situ for 3 to 5 days providing adequate postoperative analgesia and were removed uneventfully. This short case series suggests that long axis imaging of the nerve, the needle, and the catheter allows visualization of a catheter's advancement. Using to-and-fro movements, and slight rotation the needle's bevel, the catheter may be maneuvered under the ultrasound beam, which facilitates correct positioning.

Long-Axis Ultrasound Imaging of the Nerves and Advancement of Perineural Catheters Under Direct Vision

Long-Axis Ultrasound Imaging of the Nerves and Advancement of Perineural Catheters Under Direct Vision

The Sensitivity of Motor Response to Needle Nerve Stimulation During Ultrasound Guided Interscalene Catheter Placement

Neurostimulation during single shot interscalene block has a significant false negative motor response rate. Compared with tangential needle approaches for single shot block, interscalene catheter (ISC) placement commonly involves Tuohy needles inserted longitudinally to the brachial plexus. This study aimed to determine the sensitivity of neurostimulation during ultrasound-guided ISC needle placement, and the feasibility of an ultrasound-guided ISC needle endpoint. One hundred fifty-five consecutive nonstimulating ISCs were placed with the needle tip position confirmed by the sonographic spread of 5 mL dextrose 5%. Catheter advancement was then blind 2 to 3 cm past the needle tip. A 0.8 mA electrical stimulus at 2 Hz was applied throughout. When a satisfactory image was obtained, neurostimulation was ignored and the minimum motor response amplitude noted. If imaging was equivocal, a brief appropriate motor response at 0.8 mA was sought. A sustained response at <0.5 mA was only sought if imaging was suboptimal. Prior to surgery conducted under general anesthesia, 30 mL ropivacaine 0.5% was administered through the ISC. Catheter success was defined as a recovery room numerical rating pain score of </=2 (scale, 0-10). In 57% of patients, a muscle response was not elicited. An ultrasound needle endpoint was used in 92% of ISC placements, of which 96% were successful. Sustained twitches at <0.5 mA were obtained in 12 (8%) patients, 6 (4%) of these deliberately sought because of suboptimal imaging. Catheter success overall was 95%. This study suggests that the false negative motor response rate for longitudinal ISC needle placement is higher than the false negative response rate associated with tangential needle approach interscalene block. An ultrasound guided ISC needle endpoint is a feasible alternative to a neurostimulation endpoint.