David A. Stidd

Amygdala deep brain stimulation is superior to paroxetine treatment in a rat model of posttraumatic stress disorder.

BACKGROUND Posttraumatic stress disorder (PTSD) is a very debilitating disease refractory to current treatment with selective serotonin reuptake inhibitors (SSRIs) in up to 30 percent of patients, illustrating the need for new treatments of PTSD. Neuroimaging studies have shown increased activity of the amygdala of patients with PTSD. OBJECTIVE/HYPOTHESIS To investigate amygdala deep brain stimulation (DBS) as a possible novel treatment for PTSD and compare it to current treatment with a commonly used SSRI, paroxetine, in a rat PTSD model. METHODS A PTSD model was created by subjecting rats to inescapable foot shocks in the presence of a conspicuous ball. Response to treatment was measured as a decreased burying behavior when presented with the same ball 1 and 2 weeks after the shocks. Rats were treated with either daily intraperitoneal paroxetine injections or amygdala DBS via an electrode implanted 1 week prior to shocks. Generalized anxiety was assessed using an elevated plus maze. RESULTS Animals treated with amygdala DBS showed less ball burying at 2 weeks relative to the animals treated with paroxetine. The animals treated with paroxetine, however, had a lower general anxiety level compared to the DBS-treated group. CONCLUSIONS In this PTSD model, paroxetine was found to decrease the measured general anxiety level of rats that underwent the PTSD protocol, but did not counteract shock-induced hyper-vigilance toward the trauma-associated object (ball). Amygdala DBS, however, did decrease shock-induced hyper-vigilance as measured by a lower burying time, but had no effect on general anxiety assessed in the elevated plus maze. By attenuating amygdala function, DBS may act to treat the cause of PTSD, hyperactive amygdala function, and may be a promising novel alternative in cases of PTSD refractory to current pharmacological treatments.

Successful Mechanical Thrombectomy in a 2-Year-Old Male Through a 4-French Guide Catheter

A 2-year-old boy with hypoplastic left heart syndrome that required multiple cardiovascular surgeries and a heterozygous prothrombin G20210A mutation with resulting thrombophilia maintained on warfarin presented with acute right middle cerebral artery (MCA) infarction manifesting as a left hemiplegia. An MRI revealed a complete occlusion of the right M1 segment with an area of restricted diffusion in the right basal ganglia representing only a small area of acute infarction. Patchy areas of subacute infarction were also present in the right MCA territory. He underwent endovascular mechanical thrombectomy with a stent retriever. This is an account of a successful mechanical thrombectomy performed in the youngest patient reported in the English literature to date.

Evaluation of a Metal Artifacts Reduction Algorithm Applied to Postinterventional Flat Panel Detector CT Imaging

BACKGROUND AND PURPOSE: Flat panel detector CT images are degraded by streak artifacts caused by radiodense implanted materials such as coils or clips. A new metal artifacts reduction prototype algorithm has been used to minimize these artifacts. The application of this new metal artifacts reduction algorithm was evaluated for flat panel detector CT imaging performed in a routine clinical setting. MATERIALS AND METHODS: Flat panel detector CT images were obtained from 59 patients immediately following cerebral endovascular procedures or as surveillance imaging for cerebral endovascular or surgical procedures previously performed. The images were independently evaluated by 7 physicians for metal artifacts reduction on a 3-point scale at 2 locations: immediately adjacent to the metallic implant and 3 cm away from it. The number of visible vessels before and after metal artifacts reduction correction was also evaluated within a 3-cm radius around the metallic implant. RESULTS: The metal artifacts reduction algorithm was applied to the 59 flat panel detector CT datasets without complications. The metal artifacts in the reduction-corrected flat panel detector CT images were significantly reduced in the area immediately adjacent to the implanted metal object (P = .05) and in the area 3 cm away from the metal object (P = .03). The average number of visible vessel segments increased from 4.07 to 5.29 (P = .1235) after application of the metal artifacts reduction algorithm to the flat panel detector CT images. CONCLUSIONS: Metal artifacts reduction is an effective method to improve flat panel detector CT images degraded by metal artifacts. Metal artifacts are significantly decreased by the metal artifacts reduction algorithm, and there was a trend toward increased vessel-segment visualization.

Freehand thoracic pedicle screw technique using a uniform entry point and sagittal trajectory for all levels: preliminary clinical experience

OBJECT Experience with freehand thoracic pedicle screw placement is well described in the literature. Published techniques rely on various starting points and trajectories for each level or segment of the thoracic spine. Furthermore, few studies provide specific guidance on sagittal and axial trajectories. The goal of this study was to propose a uniform entry point and sagittal trajectory for all thoracic levels during freehand pedicle screw placement and determine the accuracy of this technique. METHODS The authors retrospectively reviewed postoperative CT scans of 33 consecutive patients who underwent open, freehand thoracic pedicle-screw fixation using a uniform entry point and sagittal trajectory for all levels. The same entry point for each level was defined as a point 3 mm caudal to the junction of the transverse process and the lateral margin of the superior articulating process, and the sagittal trajectory was always orthogonal to the dorsal curvature of the spine at that level. The medial angulation (axial trajectory) was approximately 30° at T-1 and T-2, and 20° from T-3 to T-12. Breach was defined as greater than 25% of the screw diameter residing outside of the pedicle or vertebral body. RESULTS A total of 219 thoracic pedicle screws were placed with a 96% accuracy rate. There were no medial breaches and 9 minor lateral breaches (4.1%). None of the screws had to be repositioned postoperatively, and there were no neurovascular complications associated with the breaches. CONCLUSIONS It is feasible to place freehand thoracic pedicle screws using a uniform entry point and sagittal trajectory for all levels. The entry point does not have to be adjusted for each level as reported in existing studies, although this technique was not tested in severe scoliotic spines. While other techniques are effective and widely used, this particular method provides more specific parameters and may be easier to learn, teach, and adopt.

Frameless neuronavigation based only on 3D digital subtraction angiography using surface-based facial registration

OBJECT Cerebrovascular lesions can have complicated abnormal anatomy that is not completely characterized by CT or MR angiography. Although 3D rotational angiography provides superior spatial and temporal resolution, catheter angiograms are not easily registered to the patient, limiting the use of these images as a source for neuronavigation. However, 3D digital subtraction angiography (DSA) contains not only vascular anatomy but also facial surface anatomy data. The authors report a novel technique to register 3D DSA images by using only the surface anatomy contained within the data set without having to fuse the DSA image set to other imaging modalities or use fiducial markers. METHODS A cadaver model was first created to assess the accuracy of neuronavigation based on 3D DSA images registered by facial surface anatomy. A 3D DSA scan was obtained of a formalin-fixed cadaver head, with acquisitions of mask and contrast runs. The right common carotid artery was injected prior to the contrast run with a 45% contrast solution diluted with water-soluble red liquid latex. One week later, the head was registered to a neuronavigation system loaded with the 3D DSA images acquired earlier using facial surface anatomy. A right pterional craniotomy was performed and 10 different vascular landmarks were identified and measured for accuracy using the neuronavigation system. Neuronavigation based only on 3D DSA was then used to guide an open clipping procedure for a patient who presented with a ruptured distal lenticulostriate aneurysm. RESULTS The accuracy of the measurements for the cadaver model was 0.71 ± 0.25 mm (mean ± SE), which is superior to the 1.8-5 mm reported for neuronavigation. The 3D DSA-based navigation-assisted surgery for the distal lenticulostriate aneurysm aided in localization, resulting in a small craniotomy and minimal brain dissection. CONCLUSIONS This is the first example of frameless neuronavigation based on 3D catheter angiography registered by only the surface anatomy data contained within the 3D DSA image set. This is an easily applied technique that is beneficial for accurately locating vascular pathological entities and reducing the dissection burden of vascular lesions.

Granulomatous Amoebic Encephalitis Caused by Balamuthia Mandrillaris in an Immunocompetent Girl

BACKGROUND Balamuthia mandrillaris is a recently recognized cause of a rare, devastating infection, granulomatous amoebic encephalitis (GAE). Presenting symptoms of GAE are nonspecific and can last for months before becoming clinically significant. Once the infection involves the central nervous system, death often results within days to weeks. A high degree of clinical suspicion is needed to correctly diagnose this infection because definitive diagnostic tests are presently limited, and even then there are only sparse data concerning effective treatment. The importance of early diagnosis is emphasized because delay likely contributes to the extremely high mortality with this infection. METHODS This study presents a previously healthy, immunocompetent 2-year-old female patient who succumbed to GAE secondary to B. mandrillaris, with the intention of raising awareness of this devastating infection. RESULTS Balamuthia amoebic encephalitis is a devastating form of amoebic encephalitis that is increasingly reported in the literature. CONCLUSIONS GAE should be considered for a patient with atypical encephalitis and single or multiple lesions with surrounding edema evident on neurodiagnostic imaging.

Spinal cord stimulation with implanted epidural paddle lead relieves chronic axial low back pain

Introduction Spinal cord stimulation (SCS) provides significant relief for lumbosacral radiculopathy refractory to both medical and surgical treatment, but historically only offers limited relief for axial low back pain (LBP). We aim to evaluate the response of chronic axial LBP treated with SCS using a surgically implanted epidural paddle lead. Materials and methods This is a retrospective review of a consecutive series of patients with exclusive LBP or predominant LBP associated with lower extremity (LE) pain evaluated and treated with SCS using an implanted paddle lead within the dorsal thoracic epidural space. Baseline LBP, and if present LE pain, were recorded using the visual analogue scale (VAS) at an initial evaluation. At a follow-up visit (a minimum of 12 months later), LBP and LE pain after a spinal cord stimulator implantation were again recorded using the VAS. Patients were also asked to estimate total LBP pain relief achieved. Results Patients with either exclusive (n=7) or predominant (n=2) axial LBP were treated with SCS by implantation of a paddle lead at an average spine level of T9. The baseline VAS score for LBP was 7.2; after a follow-up of 20 months, the score decreased to 2.3 (P=0.003). The LE pain VAS score decreased from 7.5 to 0.0 (P=0.103). Patients also reported a subjective 66.4% decrease of their LBP at follow-up. There were no surgical complications. Conclusions Axial LBP is refractory to many treatments, including SCS. SCS using a surgically implanted paddle electrode provides significant pain relief for chronic axial LPB, and is a safe treatment modality.

Monoplane 3D Overlay Roadmap versus Conventional Biplane 2D Roadmap Technique for Neurointervenional Procedures

Purpose We investigated whether a 3D overlay roadmap using monoplane fluoroscopy offers advantages over a conventional 2D roadmap using biplane fluoroscopy during endovascular aneurysm treatment. Materials and Methods A retrospective chart review was conducted for 131 consecutive cerebral aneurysm embolizations by three neurointerventionalists at a single institution. Allowing for a transition period, the periods from January 2012 to August 2012 (Time Period 1) and February 2013 to July 2013 (Time Period 2) were analyzed for radiation exposure, contrast administration, fluoroscopy time, procedure time, angiographic results, and perioperative complications. Two neurointerventionalists (Group 1) used a conventional 2D roadmap for both Time Periods, and one neurointerventionalist (Group 2) transitioned from a 2D roadmap during Time Period 1 to a 3D overlay roadmap during Time Period 2. Results During Time Period 2, Group 2 demonstrated reduced fluoroscopy time (p<0.001), procedure time (P=0.023), total radiation dose (p=0.001), and fluoroscopy dose (P=0.017) relative to Group 1. During Time Period 2, there was no difference of immediate angiographic results and procedure complications between the two groups. Through the transition from Time Period 1 to Time Period 2, Group 2 demonstrated decreased fluoroscopy time (p< 0.001), procedure time (p=0.022), and procedure complication rate (p=0.041) in Time Period 2 relative to Time Period 1. Conclusion The monoplane 3D overlay roadmap technique reduced fluoroscopy dose and fluoroscopy time during neurointervention of cerebral aneurysms with similar angiographic occlusions and complications rate relative to biplane 2D roadmap, which implies possible compensation of limitations of monoplane fluoroscopy by 3D overlay technique.

Use of a stop-flow programmable shunt valve to maximize CNS chemotherapy delivery in a pediatric patient with acute lymphoblastic leukemia

Background: The requirement for frequent intraventricular drug delivery in the setting of shunt dependence is particularly challenging in the treatment of central nervous system infection, neoplastic disease, and hemorrhage. This is especially relevant in the pediatric population where both hematogenous malignancy requiring intrathecal drug delivery and shunt-dependent hydrocephalus are more prevalent. Intrathecal and intraventricular chemotherapy agents can be prematurely diverted in these shunt-dependent patients. Case Description: We report the use of a stop-flow programmable shunt valve to maximize delivery of intraventricular chemotherapy in a child with acute lymphoblastic leukemia and disseminated intravascular coagulation who presented with spontaneous intracerebral and intraventricular hemorrhages. The patient then developed posthemorrhagic hydrocephalus and eventually progressed to shunt dependence but still required frequent intraventricular chemotherapy administration. A ventriculoperitoneal shunt, equipped with a valve that allows for near cessation of cerebrospinal fluid flow (Certas®, Codman, Raynham, MA), and a contralateral Ommaya reservoir were inserted to maximize intraventricular dissemination of chemotherapy. Conclusions: To the best of our knowledge, this is the first reported case of the use of a high-resistance programmable valve being used to virtually cease cerebrospinal fluid flow through the distal catheter temporarily in order to maximize intraventricular drug dissemination in a pediatric patient with acute lymphoblastic leukemia.

Aneurysm coil embolization using a 1.5-fr distal outer diameter microcatheter.

The current assortment of microcatheters widely used for aneurysm coil embolization may not be well suited for several anatomic variants, including excessive vascular tortuosity and small aneurysms less than 3 mm. Longer microcatheters designed with a smaller caliber that can accommodate and deliver coils may be of use in these situations. This case series and literature review illustrates the advantages and limitations of the Marathon microcatheter (Covidien, Irvine, CA, USA) when used for coil embolization of cerebral aneurysms. Despite some technical compromises including the distal marker, length, and the risk of buckling, the Marathon microcatheter was able to adequately deliver coils to achieve satisfactory occlusion of cerebral aneurysms. We found unique advantages with regards to length and smaller distal outer diameter (OD). These results may serve as a guide for the further development of a microcatheter used for coil embolization that has the features of a smaller distal OD and longer length.