Scott D. Simon

Semen analysis of military personnel associated with military duty assignments

A collaborative study between the U.S. Army Biomedical Research and Development Laboratory (USABRDL) and the National Institute for Occupational Safety and Health (NIOSH) was designed to assess fecundity of male artillery soldiers with potential exposures to airborne lead aerosols. Potential exposure assessment was based upon information provided in an interactive questionnaire. It became apparent from extensive questionnaire data that many soldiers in the initial control population had potentially experienced microwave exposure as radar equipment operators. As a result, a third group of soldiers without potential for lead or microwave exposures, but with similar environmental conditions, was selected as a comparison population. Blood hormone levels and semen analyses were conducted on artillerymen (n = 30), radar equipment operators (n = 20), and the comparison group (n = 31). Analysis of the questionnaire information revealed that concern about fertility problems motivated participation of some soldiers with potential artillery or microwave exposures. Although small study population size and the confounding variable of perceived infertility limit the reliability of the study, several statistically significant findings were identified. Artillerymen who perceived a possible fertility concern demonstrated lower sperm counts/ejaculate (P = 0.067) and lower sperm/mL (P = 0.014) than the comparison group. The group of men with potential microwave exposures demonstrated lower sperm counts/mL (P = 0.009) and sperm/ejaculate (P = 0.027) than the comparison group. Variables used to assess endocrine, accessory sex gland, and sperm cell function were not different than the comparison group. Additional studies, incorporating larger numbers of individuals, should be performed in order to more optimally characterize potential lead and microwave exposure effects on male fecundity.

Endovascular treatment of side wall aneurysms using a liquid embolic agent: a US single-center prospective trial.

OBJECTIVEOnyx HD-500 is a liquid embolic agent consisting of ethylene vinyl alcohol copolymer dissolved in dimethylsulfoxide and mixed with tantalum. This viscous embolic agent was designed to treat intracranial side wall aneurysms, but there have been no prospective published series from the United States. From this early experience, we developed several protocol revisions, technical details, and clinical pearls that have not been published for liquid embolic embolization of aneurysms. CLINICAL PRESENTATIONWe present our single-center prospective series of patients treated with Onyx HD-500 from a multicenter, randomized, controlled trial. Thirteen patients received Onyx HD-500, and their ages ranged from 43 to 81 years. Twelve patients had aneurysms on the internal carotid artery, and 1 patient had an aneurysm the vertebral artery. Every patient had an immediate postangiographic result with 90% or more occlusion by an independent core laboratory assessment. In 1 patient, the Onyx HD-500 injection was aborted, and the aneurysm was embolized with coils. Eleven of 13 patients (85%) underwent 6-month follow-up angiography that demonstrated persistent durable occlusion with no recanalization. There was 1 complication (8%) and no deaths. CONCLUSIONThis is the only prospective series of intracranial aneurysms treated with Onyx HD-500 in the United States. This is also the first publication that describes detailed procedure techniques, recommended protocol revisions, lessons learned from early complications, clinical pearls, and advantages and disadvantages of liquid embolic embolization of aneurysms.

Complete angiographic obliteration of intracranial AVMs with endovascular embolization: incomplete embolic nidal opacification is associated with AVM recurrence

Background Embolization of intracranial arteriovenous malformations (AVMs) is generally a preoperative adjunctive procedure in the USA. However, sometimes embolization can result in complete angiographic obliteration of the AVM. There is significant controversy regarding the best management strategy for this subset of patients. There is a scarcity of literature predicting which embolized, angiographically obliterated AVMs are likely to recur and which ones are cured. We present our series of patients with complete obliteration of their AVMs from embolization. Methods A prospectively maintained database identified 122 patients who underwent embolization of an intracerebral pial AVM with liquid embolics. Eighteen patients (15%) achieved complete angiographic obliteration of the AVM with embolization. We followed several parameters to assess possible predictors of recurrence. Results Fifteen of 18 patients (83%) had angiographic/anatomical follow-up to assess for AVM recurrence and 3 (17%) refused angiographic follow-up. Three patients underwent surgical resection with intraoperative angiography despite complete AVM obliteration with embolization alone. Thirteen of the 15 (87%) patients with follow-up remained obliterated at time of follow-up, and all of these patients had an embolic cast that had a similar morphology to the AVM nidus. Two of 15 patients (13%) had AVM recurrence, both of whom had incomplete embolic nidal opacification (proximal pedicle embolization). Conclusions A minority of intracranial AVMs can be safely obliterated with stand-alone embolization. Proximal occlusion of feeding arteries appears to be associated with recurrence. Prospective studies with longer follow-up and larger patient numbers are necessary.

Rebleeding risk after treatment of ruptured intracranial aneurysms

OBJECT Postprocedural rebleeding is a significant source of morbidity following endovascular treatment of ruptured intracranial aneurysms. Previous large-scale reports include the Cerebral Aneurysm Rerupture After Treatment trial, the International Subarachnoid Aneurysm Trial, and the study on Early Rebleeding after Coiling of Ruptured Cerebral Aneurysms, which reported nonprocedural rebleeding rates within 30 days of treatment of 2.7%, 1.9%, and 1.4%, respectively. However, coiling of intracranial aneurysms is in a state of continual change due to advancing device design and evolving techniques. These studies included only patients initially treated prior to 2004. In the present study the authors assess the most recent short-term results with endovascular treatment of ruptured aneurysms. METHODS A multicenter retrospective chart review was conducted of patients undergoing endovascular treatment for ruptured intracranial aneurysms between July 2004 and October 2009. The technique used, including the use of stent or balloon assistance, was evaluated. Demographic and clinical factors, such as sex, age, initial clinical presentation, aneurysm size, aneurysm location, and modified Raymond Classification following initial treatment, were also evaluated and compared between the groups in which rebleeding did and did not occur. RESULTS A total of 469 patients underwent endovascular treatment for a ruptured aneurysm; nonprocedural rehemorrhage occurred within 30 days of the initial coiling in 4 cases (0.9%). Two patients (50%) died after rehemorrhage. Stent-assisted coiling was used during the original treatment in 1 (25%) of the 4 patients with a rerupture. However, no technical, clinical, or demographic factors were found to be statistically significant in association with rebleeding. CONCLUSIONS Recent data suggest that the periprocedural rebleeding rate may be improving over time.

Embolization of a giant pediatric, posttraumatic, skull base internal carotid artery aneurysm with a liquid embolic agent

Many treatments for posttraumatic, skull base aneurysms have been described. Eight months after an all-terrain-vehicle accident, this 12-year-old girl presented with right-side Horner syndrome caused by a 33 x 19-mm internal carotid artery aneurysm at the C-1 level. We chose to treat the aneurysm with a new liquid embolic agent for wide-necked, side-wall aneurysms (Onyx HD 500). We felt this treatment would result in less morbidity than surgery and was less likely to occlude the parent artery than placement of a covered stent, especially in a smaller artery in a pediatric patient. Liquid embolic agents also appear to be associated with a lower chance of recanalization and lower cost compared with stent-assisted coil embolization. After the patient was treated with loading doses of aspirin, clopidogrel bisulfate, and heparin, 99% of the aneurysm was embolized with 9 cc of the liquid embolic agent. There were no complications, and the patient remained neurologically stable. Follow-up angiography revealed durable aneurysm occlusion after 1 year. The cost of Onyx was less than the cost of coils required for coil embolization of similarly sized intracranial aneurysms at our institution. Liquid embolic agents can provide a safe, efficacious, and cost-effective approach to treatment of select giant, posttraumatic, skull base aneurysms in pediatric patients.

Hydrodynamic comparison of the Penumbra system and commonly available syringes in forced-suction thrombectomy

Background The Penumbra system uses a coaxial separator and continuous extracorporeal suction to remove a clot from a cerebral artery. Forced-suction thrombectomy (FST) involves aspirating clots through the same reperfusion catheter using only a syringe, decreasing the procedure time and supplies needed. Objective To evaluate multiple combinations of catheters and syringes to determine the optimal pairing for use in FST. Methods Tests were performed using both the Penumbra system and syringes to aspirate water through Penumbra 0.041 inch (041), 4Max, 0.054 inch (054) and 5Max reperfusion catheters and a shuttle sheath. Dynamic pressure and flow at the catheter tip were calculated from the fill times for each system. Static pressure and force for each aspiration source were determined with a vacuum gauge. Results All syringes provided significantly higher dynamic pressure at the catheter tip than the Penumbra system (p<0.001). Increasing syringe volume significantly increased static pressure (p<0.001). Both flow and aspiration force significantly increased with catheter size (p<0.001). Cases are presented to demonstrate the clinical value of the laboratory principles. Conclusions Maximizing static and dynamic pressure when performing FST is achieved by aspirating with a syringe possessing both the largest volume and the largest inlet diameter available. Maximizing aspiration force and flow rate is achieved by using the largest catheter possible.

Use of intracranial stenting to secure unstable liquid embolic casts in wide-neck sidewall intracranial aneurysms.

BACKGROUND Onyx HD 500 (eV3, Irvine, CA) is a high-viscosity liquid embolic agent that has recently been approved in the United States as a humanitarian use device for the treatment of wide-neck sidewall intracranial aneurysms. Preliminary evidence suggest that liquid embolic agents can provide improved angiographic results with a lower incidence of recanalization compared to coil embolization. OBJECTIVE To report unstable Onyx casts and how to deal with them. METHODS We report 4 cases of intracranial aneurysms treated with Onyx HD 500 in which, after the aneurysm was successfully obliterated, the Onyx cast was noted to have 1 of 2 types of embolic cast instability. In all 4 cases, an intracranial stent or vascular reconstruction device (VRD) was placed across the Onyx cast at the aneurysm orifice and the cast was stabilized. CONCLUSION This series is the first published description of Onyx HD 500 aneurysm cast instability. It is also the first report of using a stent or vascular reconstruction device rescue technique to secure an unstable Onyx cast and represents a new indication for these devices.

Biomechanical attributes of microcatheters used in liquid embolization of intracranial aneurysms

Objective A steel-reinforced and a nitanol-reinforced microcatheter are both approved for use with Onyx HD-500 embolization of intracranial aneurysms. The biomechanical behavior of these catheters when used with high viscosity embolic liquids is poorly understood. We performed biomechanical laboratory testing and examined our clinical experience to identify situations where one catheter might have an advantage over the other. Methods The catheters were tested for detachment force from aneurysm cast, burst pressure, burst location, and pressure under dynamic delivery pressure. The results were compared using ANOVA. Results The average detachment forces for the Echelon 10, 14, and Rebar 14 catheters were 97.6, 76.825, and 62.6 g, respectively (p=0.023). The average burst pressures for the Echelon 10, 14, and Rebar 14 were 1108, 1213, and 1365 psi, respectively (p=0.003). The average burst location was 26.0, 20.0, and 4.5 mm, respectively, from the tip (p=0.035). There was no significant difference regarding burst location (p=0.39). The delivery pressures of the catheters were not significant (p=0.98). Two cases are presented that illustrate the importance of these findings and how they can be incorporated into practice. Conclusion The lower detachment force of the Rebar 14 makes it ideal for liquid embolization, but its stiffness makes it less desirable for accessing smaller aneurysms or navigating tortuous anatomy. The Echelon 10 should be avoided unless it is the only catheter that can access an aneurysm because of small size or tortuous anatomy. In such cases, the higher detachment force suggests a stent should be in place to prevent the cast from being destabilized.

Dural arteriovenous fistulas masquerading as dural sinus thrombosis

The authors report dural sinus thrombosis diagnosed in 2 patients based on noninvasive imaging results, which were revealed to be dural arteriovenous fistulas (DAVFs) diagnosed using digital subtraction (DS) angiography. The first patient was a 63-year-old man who presented with headaches. Magnetic resonance venography was performed and suggested dural sinus thrombosis of the left transverse sinus and jugular vein. He was administered warfarin anticoagulation therapy but then suffered multiple intracranial hemorrhages. A DS angiogram was requested for a possible dural sinus thrombectomy, but the DS angiogram revealed a DAVF. The patient underwent serial liquid embolization with complete obliteration of the DAVF. The second patient, an 11-year-old boy, also presented with headaches and was diagnosed with dural sinus thrombosis on MR imaging. A DS angiogram was also requested for a possible thrombectomy and revealed a DAVF. This patient underwent serial liquid embolization and eventual operative resection. These reports emphasize that different venous flow abnormalities can appear similar on noninvasive imaging and that proper diagnosis is critical to avoid contraindicated therapies.

Multicenter registry of liquid embolic treatment of cerebral aneurysms.

OBJECTIVE The Cerebral Aneurysm Multicenter European Onyx trial was the first multicenter prospective case series using liquid embolization for cerebral aneurysms. It suggested a possible decreased risk for recanalization of smaller aneurysms compared with coil embolization. After publication of that trial, the Onyx HD embolic agent, injection devices, and treatment protocols have all been updated and improved to increase efficacy and decrease adverse events. We present the results from a multicenter registry of liquid embolization treatments using the current method and materials. We hypothesize that the evolution of this technique will result in lower complication and recanalization rates when compared with earlier series. METHODS Surgeons performing liquid embolization submitted data about consecutive patients and procedures. The data provided were used to determine what characteristics were associated with durable occlusion and recanalization. RESULTS One hundred thirteen patients at 25 medical centers throughout the United States underwent liquid embolization. Of these, 110 had follow-up data of at least 6 months. Seventeen patients (15%) experienced a complication and 4 (3.5%) experienced procedure-related ischemic stroke or death. Nine patients (8.1%) had aneurysm recanalization and 5 (4.5%) required retreatment. All retreatments were accomplished with further liquid embolization and were stable at the last follow-up angiogram available. Those with durable occlusion had smaller aneurysm size (mean, 10 mm vs. 17 mm) (P = 0.03) and were de novo (P = 0.02). CONCLUSIONS Recent advances in liquid embolization have led to decreased recanalization and complications. Liquid embolization is more likely to achieve a durable result in smaller aneurysms that have not been previously treated.