Shakeel A. Chowdhry

Indocyanine green angiography in the surgical management of cerebral arteriovenous malformations: lessons learned in 130 consecutive cases.

BACKGROUND: Indocyanine green (ICG) angiography is commonly used to map the vascular configuration of cerebral arteriovenous malformations (AVMs) during resection. OBJECTIVE: To determine whether ICG improves rates of resection and clinical outcomes. METHODS: A retrospective chart review was done for all patients undergoing resection of an AVM by the senior author (R.F.S.) between 2007 and 2011. Operative reports, hospital records, and radiographic imaging were used to determine the use of ICG, the incidence of residual disease, and clinical outcomes. RESULTS: A total of 130 cases (56 ICG, 74 non-ICG) were identified. Average AVM grade (2.2 vs 2.4) and size (2.7 vs 2.7 cm) were similar between the ICG and non-ICG groups, respectively. ICG was more often used when the AVM nidus was close to the cortical surface (71.4% vs 17.6%; P = .001) or lobar (82.1% vs 54.1%; P = .008). Eighteen patients (13.8%) were noted to have residual disease. Reoperation rates and change in modified Rankin Scale score were not different between the 2 groups (12.5% vs 14.9%, P = .8; 0.6 vs 0.4, P = .17). There were no ICG-attributable complications. CONCLUSION: ICG videoangiography is a quick and safe method of intraoperatively mapping the angioarchitecture of superficial AVMs, but it is less helpful for deep-seated lesions. This modality alone does not improve the identification of residual disease or clinical outcomes. Surgeon experience with extensive study of preoperative vascular imaging is paramount to achieving acceptable clinical outcomes. Formal angiography remains the gold standard for the evaluation of AVM obliteration. ABBREVIATIONS: AVM, arteriovenous malformation DSA, digital subtraction angiography ICG, indocyanine green

Intraventricular Neuroendoscopy: Complication Avoidance and Management

In the modern era, neuroendoscopy has had an increasingly prominent role in neurosurgery. As attention has focused the development of minimally invasive surgical methods, neuroendoscopy has advanced both as an independent treatment modality for various neurologic disorders and as an adjunct to microneurosurgery. Neuroendoscopy is distinct from traditional surgery, and a thorough understanding of its unique attributes is required to attain maximal benefit. In addition to its advantages, neuroendoscopy is associated with unique obstacles that must be anticipated, appreciated, and accounted for to prevent complications. This article outlines techniques to reduce and manage complications during more common intraventricular neuroendoscopic procedures including endoscopic third ventriculostomy (ETV), colloid cyst resection, tumor biopsy and resection, and treatment of loculated hydrocephalus.

Long-term follow-up of blister aneurysms of the internal carotid artery.

BACKGROUND Blister aneurysms of the internal carotid artery (ICA) are uncommon. There is a paucity of data on the long-term outcomes of patients. OBJECTIVE To review our experience with the treatment of these lesions. METHODS We retrospectively reviewed all aneurysms treated at our institution between 1994 and 2005. Relevant operative notes, radiology reports, and inpatient/outpatient records were reviewed. RESULTS Seventeen patients (3 male, 14 female) with 18 blister aneurysms of the ICA were identified. The mean age was 44.6 years (range, 17-72; median, 42 years). Twelve patients (70.6%) presented with aneurysmal subarachnoid hemorrhage. The mean admission Glasgow Outcome Scale score was 4.3 (range, 2-5; median, 5). All patients were initially treated using microsurgical technique with direct clipping (n = 15; 83.3%) or clip-wrapping with Gore-Tex (n = 3, 16.7%). There were 4 cases of intraoperative rupture, all associated with attempted direct clipping; all 4 cases were successfully clipped. Two cases rebled post-treatment. Both rebleeding episodes were managed with endovascular stenting. Follow-up angiography was available for 14 patients and revealed a new aneurysm adjacent to the site of clipping in 1 patient and in-stent stenosis in 2. At the mean follow-up of 74.5 months (median, 73; range, 7-165), the mean Glasgow Outcome Scale score was 4.6 (range, 2-5; median, 5). CONCLUSION Microsurgical treatment of blister aneurysms of the ICA results in excellent outcome. In the evolution of treating these friable aneurysms, we have modified our clip-wrapping technique and use this technique when direct clipping is not feasible.

History of the Kleeblattschädel deformity: Origin of concepts and evolution of management in the past 50 years

The history and evolution of surgical strategies for the treatment of Kleeblattschädel deformity are not well described in the medical literature. Kleeblattschädel anomaly is one of the most formidable of the craniosynostoses, requiring a multidisciplinary team for surgical treatment. The initial descriptions of this cloverleaf deformity and the evolution of surgical treatment are detailed in the present report. Two illustrative cases of Kleeblattschädel deformity, syndromic and nonsyndromic craniosynostoses treated by the senior authors, are also described along with insights into operative strategies.

Contralateral interhemispheric approach to deep-seated cavernous malformations: surgical considerations and clinical outcomes in 31 consecutive cases.

BACKGROUND Deep-seated periventricular cavernous malformations of the basal ganglia or thalamus can be approached via an interhemispheric craniotomy. OBJECTIVE To determine surgical efficacy and clinical outcomes of the contralateral interhemispheric approach. METHODS Retrospective chart review was performed on patients undergoing an interhemispheric approach for the resection of deep-seated cavernous malformation by the senior author (R.F.S.) between 2005 and 2013. Demographic data and clinical outcomes were reviewed. Pre- and postoperative imaging were analyzed for lesion location, size, associated venous anomaly, proximity to ventricle, and presence of residual. RESULTS Twenty-one patients underwent a contralateral interhemispheric-transventricular approach, 7 patients had a contralateral interhemispheric-transcingulate approach and 3 patients had a contralateral interhemispheric-transchoroidal approach. Mean age was 40.1 years, and the majority were female (58.1%). Mean maximum cavernoma diameter was 1.97 cm, and 43.8% reached the surface of the ventricle. Average follow-up was 8.9 months, with complete resection achieved in 96.8% of patients. At last follow-up, 61.3% of patients remained stable and 29.0% had improved. Of the patients, 6.5% experienced transient weakness that resolved at last follow-up, and 1 patient (3.2%) had short-term memory problems. There were no surgical mortalities. CONCLUSION The contralateral interhemispheric approach is a safe, clinically well tolerated, and surgically efficacious approach to deep-seated cavernomas.

Robotic autopositioning of the operating microscope.

BACKGROUND: Use of the operating microscope has become pervasive since its introduction to the neurosurgical world. Neuronavigation fused with the operating microscope has allowed accurate correlation of the focal point of the microscope and its location on the downloaded imaging study. However, the robotic ability of the Pentero microscope has not been utilized to orient the angle of the microscope or to change its focal length to hone in on a predefined target. OBJECTIVE: To report a novel technology that allows automatic positioning of the operating microscope onto a set target and utilization of a planned trajectory, either determined with the StealthStation S7 by using preoperative imaging or intraoperatively with the microscope. METHODS: By utilizing the current motorized capabilities of the Zeiss OPMI Pentero microscope, a robotic autopositioning feature was developed in collaboration with Surgical Technologies, Medtronic, Inc. (StealthStation S7). The system is currently being tested at the Barrow Neurological Institute. RESULTS: Three options were developed for automatically positioning the microscope: AutoLock Current Point, Align Parallel to Plan, and Point to Plan Target. These options allow the microscope to pivot around the lesion, hover in a set plane parallel to the determined trajectory, or rotate and point to a set target point, respectively. CONCLUSION: Integration of automatic microscope positioning into the operative workflow has potential to increase operative efficacy and safety. This technology is best suited for precise trajectories and entry points into deep-seated lesions.

Cerebral revascularization for ischemic disease in the 21st century

Shortly after the first extracranial to intracranial (EC–IC) carotid artery bypass was performed by Yasargil in 1967 for internal carotid artery occlusion, cerebral revascularization became widely accepted in the neurosurgical field, and the procedures became increasingly used as practitioners began to master the technical aspects of the surgery. The procedures were performed for intracranial arterial stenosis and occlusion and used as an adjunct in the treatment of large aneurysms and skull base tumors. The results of the EC–IC bypass group trial in 1985 were surprising to many and sobering to all; EC–IC bypass for stenosis or occlusion of the high internal carotid artery or middle cerebral artery did not decrease the risk of subsequent stroke compared with medical management. Rather, the incidence of stroke increased, and the events were noted to occur sooner than with medical therapy alone. Despite the known limitations of this landmark study, the number of EC–IC bypass procedures fell precipitously over the ensuing decades. Despite this significant setback, cerebral revascularization is not obsolete. This article revisits the sequence of events leading to the rise of revascularization surgery and recaps the impact of the EC–IC bypass trial. The limitations of the trial are discussed, as are current studies evaluating the efficacy of cerebrovascular bypass procedures for symptomatic carotid occlusive disease. The authors review the accepted indications for bypass surgery in the early 21st century.

N-butyl 2-cyanoacrylate (n-BCA) embolization of a cerebellar hemangioblastoma

Hemangioblastomas (HBs) are highly vascular tumors whose resection can be associated with significant bleeding. Angioembolization has been used as an adjunct to surgical therapy, but particle embolization of cerebellar HBs has been associated with hemorrhage and resultant morbidity and mortality. We present a case of successful n-BCA embolization of an HB of the cerebellum.

KLF6 contributes to myeloid cell plasticity in the pathogenesis of intestinal inflammation

Inflammatory bowel disease (IBD) is associated with dysregulated macrophage responses, such that quiescent macrophages acquire a pro-inflammatory activation state and contribute to chronic intestinal inflammation. The transcriptional events governing macrophage activation and gene expression in the context of chronic inflammation such as IBD remain incompletely understood. Here, we identify Kruppel-like transcription factor-6 (KLF6) as a critical regulator of pathogenic myeloid cell activation in human and experimental IBD. We found that KLF6 was significantly upregulated in myeloid cells and intestinal tissue from IBD patients and experimental models of IBD, particularly in actively inflamed regions of the colon. Using complementary gain- and loss-of-function studies, we observed that KLF6 promotes pro-inflammatory gene expression through enhancement of nuclear factor κB (NFκB) signaling, while simultaneously suppressing anti-inflammatory gene expression through repression of signal transducer and activator of transcription 3 (STAT3) signaling. To study the in vivo role of myeloid KLF6, we treated myeloid-specific KLF6-knockout mice (Mac-KLF6-KO) with dextran sulfate sodium (DSS) and found that Mac-KLF6-KO mice were protected against chemically-induced colitis; this highlights the central role of myeloid KLF6 in promoting intestinal inflammation. Collectively, our results point to a novel gene regulatory program underlying pathogenic, pro-inflammatory macrophage activation in the setting of chronic intestinal inflammation.

Microvascular decompression for hemifacial spasm secondary to vertebrobasilar dolichoectasia: Surgical strategies, technical nuances and clinical outcomes

Hemifacial spasm (HFS) due to direct compression of the facial nerve by a dolichoectatic vertebrobasilar artery is rare. Vessels are often non-compliant and tethered by critical brainstem perforators. We set out to determine surgical strategies and outcomes for this challenging disease. All patients undergoing surgery for HFS secondary to vertebrobasilar dolichoectasia were reviewed. Hospital records, clinic notes and radiographic imaging were collected for outcome measures. Seventeen patients (eight males, nine females) were identified. Sixteen patients (94%) were treated with Teflon pledgets (DuPont, Wilmington, DE, USA) and one (6%) patient had a vascular sling placed around a severely diseased vertebral artery. All patients had significant reduction in symptoms and 82% of patients had complete resolution of symptoms (average follow-up: 41.4 months). One patient suffered persistent facial nerve paresis and swallowing difficulty. Two other patients suffered a 1 point decrease in the House-Brackmann facial nerve grading scale. Four patients (23%) required re-operation (infection, cerebrospinal fluid leak, and two patients with delayed recurrence of HFS). Of the latter, one patient required repositioning of a Teflon pledget and another patient underwent a sling decompression. There were no perioperative strokes or death. Excellent relief of symptoms with acceptable preoperative morbidity can be achieved using Teflon pledgets alone in most cases. In recalcitrant cases, sling transposition can be used to further augment the decompression. Careful attention must be paid to prevent vascular kinking and preserve brainstem perforators.