Preoperative angiographic protocol for the surgical management of spinal dural arteriovenous fistulas: a technical nuance for safe minimally invasive surgery

BACKGROUND

Interruption of the fistoulus point is the goal of the treatment of spinal dural arteriovenous fistula (dAVFs). Microsurgery still represents a highly efficient treatment in terms of complete occlusion with the lowest risk of recurrence rate. It is reported that the hardest step consists in finding the fistulous site itself, potentially extending surgical access and time, and increasing potential post-operative surgical-related complications. The accurate preoperative detection of the shunt and spinal level together is crucial for guiding optimal, fast and safe microsurgical treatment.

METHODS

In the present paper, the authors describe a preoperative angiographic protocol for achieving a safe and simple resection of spinal dAVFs based on a six-year Institutional experience of forty-two patients who underwent minimally invasive. Two illustrative cases are also included in order to support the technical descriptions.

RESULTS

The suspected artery associated to the vascular malformation of interest is studied in our angiographic protocol through non-subtracted selective acquisitions in the lateral projection. The resulting frames are reconstructed with 3D Rotational Angiography. The implementation of the preoperative angiographic protocol allowed 100% of intraoperative identification of the fistoulus point in all cases with the use of minimally invasive approach.

CONCLUSIONS

Nowadays, neurosurgeons advocate for minimally invasive procedures and low morbidity risk procedures for the treatment of spinal dAVFs.Our preoperative approach for accurate angigoraphic localization of the fistoulus point through non-subtracted and 3D reconstructed angiography allowed to achieve safe and definitive occlusion of the shunt.

The Use of Intraoperative Microvascular Doppler in Vascular Neurosurgery: Rationale and Results-A Systematic Review

Surgical treatment of neurovascular lesions like intracranial aneurysms, arteriovenous malformations and arteriovenous dural fistulas is still associated with high morbidity. Several recent studies are providing increasing insights into reliable tools to improve surgery and reduce complications. Inadvertent vessel compromise and incomplete occlusion of the lesion represent the most possible complications in neurovascular surgery. It is clear that direct visual examination alone does not allow to identify all instances of vessel compromise. Various modalities, including angiography, microvascular Doppler and neurophysiological studies, have been utilized for hemodynamics of flow vessels in proper clipping of the aneurysm or complete obliteration of the lesion. We intended to review the current knowledge about the intraoperative microvascular Doppler (iMDS) employment in the most updated literature, and explore the most recent implications not only in intracranial aneurysms but also in neurovascular lesions like arteriovenous malformations (AVMs) and arteriovenous dural fistulas (AVDFs). According to the PRISMA guidelines, systematic research in the most updated platform was performed in order to provide a complete overview about iMDS employment in neurovascular surgery. Twelve articles were included in the present paper and analyzed according to specific research areas. iMDS employment could represent a crucial tool to improve surgery in neurovascular lesions. The safety and effectiveness of the surgical treatment of neurovascular lesions like intracranial aneurysm and other neurovascular lesions like AVMs and AVDFs requires careful and accurate consideration regarding the assessment of anatomy and blood flow. Prognosis may depend on suboptimal or incomplete exclusion of the lesion.

Endovascular and surgical obliteration rates of spinal dural arteriovenous fistulae: a single UK Centre experience

OBJECTIVE

Endovascular treatment (EVT) of spinal dural arteriovenous fistulae (SDAVF) has become increasingly popular given its less invasive nature. This study aims to assess radiological obliteration rates after surgery and EVT for SDAVF in a major tertiary referral centre serving a population of 2.2 million.

METHOD

A retrospective review of all patients diagnosed with SDAVF between February 2010 and February 2018 was undertaken, identifying baseline demographics, treatment modality and the final radiological outcome (i.e., persistence of the SDAVF). Patients were identified from the departmental neurovascular database, clinical notes and imaging reports.

RESULTS

Twenty patients were identified with an angiographically confirmed SDAVF. Two (10%) were managed conservatively. Nine patients (45%) underwent EVT. Obliteration was achieved in one patient (11%) after a single procedure, while one patient required two sessions. Further surgery was required in five patients (56%) to achieve complete obliteration. Nine patients (45%) underwent surgical disconnection as first treatment. Obliteration was radiologically confirmed in eight patients (89%). No radiological (MRI or angiographic) follow-up data was available for two patients (one from each group) and these were excluded from analysis. In this study, the obliteration rate of SDAVF after surgery was superior compared to EVT (p <0.01).

CONCLUSION

Complete obliteration and recurrence rates after single treatment with EVT were inferior compared to surgical intervention. EVT may be better suited for specific presentations of SDAVF either in isolation or as an adjunct in multi-modality treatment. A national registry of outcomes may aid ongoing refinement of patient selection for EVT.

The Role of Cisternostomy and Cisternal Drainage in the Treatment of Aneurysmal Subarachnoid Hemorrhage: A Comprehensive Review

Aneurysmal subarachnoid hemorrhage (aSAH) provokes a cascade reaction that is responsible for early and delayed brain injuries mediated by intracranial hypertension, hydrocephalus, cerebral vasospasm (CV), and delayed cerebral ischemia (DCI), which result in increased morbidity and mortality. During open microsurgical repair, cisternal access is achieved essentially to gain proximal vascular control and aneurysm exposition. Cisternostomy also allows brain relaxation, removal of cisternal clots, and restoration of the CSF dynamics through the communication between the anterior and posterior circulation cisterns and the ventricular system, with the opening of the Membrane of Liliequist and lamina terminalis, respectively. Continuous postoperative CSF drainage through a cisternal drain (CD) is a valuable option for treating acute hydrocephalus and intracranial hypertension. Moreover, it efficiently removes the blood and toxic degradation products, with a potential benefit on CV, DCI, and shunt-dependent hydrocephalus. Finally, the CD is an effective pathway to administer vasoactive, fibrinolytic, and anti-oxidant agents and shows promising results in decreasing CV and DCI rates while minimizing systemic effects. We performed a comprehensive review to establish the adjuvant role of cisternostomy and CD performed in cases of direct surgical repair for ruptured intracranial aneurysms and their role in the prevention and treatment of aSAH complications.

Peculiar Neurological Examination Secondary to Persistent Primitive Hypoglossal Artery

A persistent primitive hypoglossal artery (PPHA) is an anatomical variant resulting in persistent carotid-vertebrobasilar anastomoses. This variant arises from the distal cervical segment of the internal carotid artery (ICA) between C1 and C3 and passes through an enlarged hypoglossal canal to join the basilar circulation. This case report describes a 60-year-old male with an acute ischemic event secondary to an occlusion in the right ICA and PPHA, resulting in a unique physical examination. Digital subtraction angiography (DSA) was utilized to visualize occlusion of the right common carotid artery with no residual right internal carotid artery or right vertebral artery filling. The patient's presenting symptoms yielded a unique neurological examination, making it difficult to localize a solitary lesion, which would account for the patient's acute presentation. In retrospect, with angiography revealing a right PPHA, his presentation fit more thoroughly with the clinical picture. With the increased utility of neuro-endovascular procedures, clinicians have a higher probability of encountering diverse angiographical findings. With this case report, we would like to familiarize practitioners with the presence of PPHA, present unique imaging findings involving typically isolated vascular territories, and stress the importance of clinical judgment when making decisions regarding stroke care.

Heart rate and heart rate variability during diagnostic and interventional neuroendovascular procedures

INTRODUCTION

Heart rate variability (HRV) reflects the activity of the autonomic nervous system (ANS) and can be used as a potential predictor of stress-related cardiovascular diseases. This study aimed to assess whether physical and mental strain during the performance of cerebral endovascular procedure influence time-domain HRV parameters in operating surgeon.

MATERIALS AND METHODS

Heart rate (HR) and HRV metrics were measured using a HR sensor chest strap before, during, and after neuroendovascular interventions performed by a single neurosurgeon. Three consecutive data series were reported by recording time domain: before procedure, during and after performing endovascular procedures. HR and HRV parameters were recorded during diagnostic and interventional neuroendovascular procedures. HR and HRV measures were analyzed by procedure type and recording time domain.

RESULTS

HRV measures of a single endovascular neurosurgeon were recorded during 50 procedures. The median intraprocedural HRV score was the lowest and the median HR was the highest (HRV: 52, HR: 89 bpm) compared to preprocedural (HRV: 59, HR: 70 bpm) and postprocedural cardiovascular measures (HRV: 53, HR: 79, bpm, p < 0.001). On univariate linear regression, a negative association of interventional procedures with lower intraprocedural (β = -0.905, p = 0.001) and postprocedural (β = -1.12, p < 0.001) HRV scores compared to the diagnostic procedures was noted.

CONCLUSIONS

HRV is a reliable tool to measure cardiovascular and mental stress. Interventional neuro-endovascular procedures seem to negatively impact the cardiovascular measures of neurointerventionalists. Further longitudinal studies utilizing HRV are warranted to address their long-term effects on the mental health of physicians.

A novel, reusable, realistic neurosurgical training simulator for cerebrovascular bypass surgery: Iatrotek® bypass simulator validation study and literature review

Background

Microanastomosis is a challenging technique requiring continuous training to be mastered. Several models have been proposed, but few effectively reflect a real bypass surgery; even fewer are reusable, most are not easily accessible, and the setting is often quite long. We aim to validate a simplified, ready-to-use, reusable, ergonomic bypass simulator.

Methods

Twelve novice and two expert neurosurgeons completed eight End-to-End (EE), eight End-to-Side (ES), and eight Side-to-Side (SS) microanastomoses using 2-mm synthetic vessels. Data on time to perform bypass (TPB), number of sutures and time required to stop potential leaks were collected. After the last training, participants completed a Likert Like Survey for bypass simulator evaluation. Each participant was assessed using the Northwestern Objective Microanastomosis Assessment Tool (NOMAT).

Results

When comparing the first and last attempts, an improvement of the mean TPB was registered in both groups for the three types of microanastomosis. The improvement was always statistically significant in the novice group, while in the expert group, it was only significant for ES bypass. The NOMAT score improved in both groups, displaying statistical significance in the novices for EE bypass. The mean number of leakages, and the relative time for their resolution, also tended to progressively reduce in both groups by increasing the attempts. The Likert score expressed by the experts was slightly higher (25 vs. 24.58 by the novices).

Conclusions

Our proposed bypass training model may represent a simplified, ready-to-use, reusable, ergonomic, and efficient system to improve eye-hand coordination and dexterity in performing microanastomoses.

The art of combining neuroanatomy and microsurgical skills in modern neurosurgery

Neurosurgical training outside the operating room has become a priority for all neurosurgeons around the world. The exponential increase in the number of publications on training in neurosurgery reflects changes in the environment that future neurosurgeons are expected to work in. In modern practice, patients and medicolegal experts demand objective measures of competence and proficiency in the growing list of techniques available to treat complex neurosurgical conditions. It is important to ensure the myriad of training models available lead to tangible improvements in the operating room. While neuroanatomy textbooks and atlases are continually revised to teach the aspiring surgeon anatomy with a three-dimensional perspective, developing technical skills are integral to the pursuit of excellence in neurosurgery. Parapharsing William Osler, one of the fathers of neurosurgical training, without anatomical knowledge we are lost, but without the experience and skills from practice our journey is yet to begin. It is important to constantly aspire beyond competence to mastery, as we aim to deliver good outcomes for patients in an era of declining case volumes. In this article, we discuss, based on the literature, the most commonly used training models and how they are integrated into the treatment of some surgical brain conditions.

Microsurgical Treatment of a Giant Intracavernous Carotid Artery Aneurysm in a Pediatric Patient: Case Report and Literature Review

Intracranial aneurysms in children account for 4%-5% of all cases, with 20% being considered giant (>25 mm). The main sites of occurrence are the internal carotid artery (ICA) and the middle cerebral artery (MCA). Rupture and secondary subarachnoid hemorrhage occur in approximately 55%-72.5% of cases, with a 10%-23% mortality rate. We report the case of a previously healthy nine-year-old girl who developed sudden, severe right retroocular pain and a holocranial headache as a mode of onset. Besides, the patient presented with double vision, and her relatives sought medical attention. Paresis of the right III, IV, and VI cranial nerves was found at physical examination. An MRI and digital subtraction angiography showed the presence of a giant aneurysm in the cavernous portion of the ICA with a mass effect. The patient was treated surgically through a high-flow bypass using a radial artery graft and trapping of the aneurysm. She had an uneventful postoperative course and was discharged three days after the operation to continue follow-up at the outpatient clinic. The therapeutic options were: a) an endovascular approach using flow diverters or stenting and coiling; or b) surgical treatment with proximal closure of the ICA if the patient had good collateral circulation or trapping the aneurysm combined with a high-flow bypass if the collateral circulation was not good or absent. After discussion, we decided on the surgical option. Even when the surgery was successful in this case, there is no consensus about the best way to treat it; the selection should be based on the center´s experience when confronting this rare entity.

Randomized study comparing 3D virtual reality and conventional 2D on-screen teaching of cerebrovascular anatomy

OBJECTIVE

Performing aneurysmal clipping requires years of training to successfully understand the 3D neurovascular anatomy. This training has traditionally been obtained by learning through observation. Currently, with fewer operative aneurysm clippings, stricter work-hour regulations, and increased patient safety concerns, novel teaching methods are required for young neurosurgeons. Virtual-reality (VR) models offer the opportunity to either train a specific surgical skill or prepare for an individual surgery. With this study, the authors aimed to compare the spatial orientation between traditional 2D images and 3D VR models in neurosurgical residents or medical students.

METHODS

Residents and students were each randomly assigned to describe 4 aneurysm cases, which could be either 2D images or 3D VR models. The time to aneurysm detection as well as a spatial anatomical description was assessed via an online questionnaire and compared between the groups. The aneurysm cases were 10 selected patient cases treated at the authors' institution.

RESULTS

Overall, the time to aneurysm detection was shorter in the 3D VR model compared to 2D images, with a trend toward statistical significance (25.77 ± 37.26 vs 45.70 ± 51.94 seconds, p = 0.052). No significant difference was observed for residents (3D VR 24.47 ± 40.16 vs 2D 33.52 ± 56.06 seconds, p = 0.564), while in students a significantly shorter time to aneurysm detection was measured using 3D VR models (26.95 ± 35.39 vs 59.16 ± 44.60 seconds, p = 0.015). No significant differences between the modalities for anatomical and descriptive spatial mistakes were observed. Most participants (90%) preferred the 3D VR models for aneurysm detection and description, and only 1 participant (5%) described VR-related side effects such as dizziness or nausea.

CONCLUSIONS

VR platforms facilitate aneurysm recognition and understanding of its spatial anatomy, which could make them the preferred method compared to 2D images in the years to come.

Does the discontinuation time of antiplatelet or anticoagulation treatment affect hemorrhagic complications in patients undergoing craniotomy for neurovascular lesions?

BACKGROUND

The number of patients treated with platelet inhibitors (PI) and/or anticoagulants (AC) in neurosurgery is increasing. The aim of this study was to analyse the effect of PI/AC discontinuation time on hemorrhagic events after craniotomy for neurovascular pathologies.

METHODS

The 30-day postoperative bleeding rates were retrospectively compared between short (≤5 days) and long (>5 days) discontinuation time of PI/AC before and after surgery. Kaplan-Meier survival analysis comparing time to postoperative bleeding and the effect of PI/AC discontinuation time on bleeding rates were analysed. Potential risk factors for postoperative bleeding were further analysed in uni- and multivariate analysis.

RESULTS

Out of 215 consecutive patients undergoing craniotomy for neurovascular lesions between January 2009 and April 2019, 23.3% were treated with PI/AC. Of these 36% (n = 18) and 20.8% (n = 10) were included in the short pre- and postoperative discontinuation group, respectively. Bleeding rates were comparable between the pre- and postoperative short and long discontinuation groups (preoperative 11.1% vs 10%, p = .659; postoperative 0% vs 13.2%, p = .566). In-hospital mortality rates and time to bleed of the groups were comparable as well. Similarly, the rate for thromboembolic events was not significantly affected by the pre- or postoperative discontinuation time of PI/AC. After multivariate analysis preoperative bleeding of the lesion was significantly associated with postoperative bleeding.

CONCLUSIONS

Patients with short discontinuation time of PI/AC treatment undergoing craniotomy for the treatment of neurovascular lesions do not appear to have increased rates of postoperative bleeding.

The Fluorescent Patient: An Unusual Effect of Fluorescein Angiography

Although fluorescein is widely used for intraoperative angiography, some of its side effects remain obscure. In this report, we present the case of a 41-year-old patient with chronic ischemia caused by moyamoya syndrome who underwent bypass revascularization with intraoperative fluorescein angiography (FA). Immediately after the surgery, the patient presented homogeneous fluorescence of the entire skin. We discuss this curious phenomenon as well as other side effects that may arise due to FA.

Application of the Endoscopic Micro-Inspection Tool QEVO® in the Surgical Treatment of Anterior Circulation Aneurysms-A Technical Note and Case Series

Introduction: The application of neuro-endoscopes in cerebral aneurysm surgery may help to avoid unintended aneurysm remnants and the accidental clipping of perforating arteries and aid the detection of blood collecting in the subdural spaces. Here, we present our experience with the novel endoscopic micro-inspection tool QEVO® (Carl Zeiss Meditec, Germany) in aneurysm surgery.

Materials and Equipment: In all patients the surgical microscope KINEVO® (Carl Zeiss Meditec, Germany) and the Microinspection tool QEVO® were applied.

Methods: The case series comprises 22 unruptured cerebral aneurysms of the anterior circulation. All aneurysms were treated surgically. All patients routinely underwent computed tomography and digital subtraction angiography within 10 days after surgery.

Results: No aneurysm remnants, cerebral ischemic deficits, or subdural hematomas were detected.

Discussion: In this technical note, we discuss the benefits and limitations of the QEVO® tool and illustrate the major paradigms by means of intraoperative photographs.

Posterior Internal Frontal Artery Vascularization of the Precentral Gyrus Responsible for Proximal Arm Movement: Insight from a Case of Coil Migration

Our knowledge of the vascularization of the precentral gyrus by branches of the anterior cerebral artery (ACA) relies mainly on anatomical cadaveric dissection. A distal branch of the ACA known as the posterior internal frontal artery (PIFA) is thought to vascularize the precentral gyrus responsible for proximal arm movement; however, no clinical correlation has yet been reported to confirm this relation. In this manuscript, we report a case of coil migration in the PIFA, causing proximal arm weakness in a 58-year-old woman treated for aneurysmal subarachnoid hemorrhage. The occurrence of clinical signs immediately following coil migration into the PIFA, combined with evidence of stroke in the cortical territory related to arm movement as seen on imaging, indicates that the PIFA indeed can vascularize this lateral portion of the precentral gyrus. This case confirms our current understanding of the vascularization of the precentral gyrus by distal ACA branches, in particular the PIFA.

[Perimedullary arteriovenous fistula. Case report and literature review]

Arteriovenous fistula is a common vascular abnormality of spinal cord and meninges. This disease is more common in young men. Clinical manifestation includes progressive sensitive and motor disorders. However, acute symptoms including impaired consciousness, head or back pain are also possible. The authors describe a rare case. A 15-year-old boy experienced acute depression of consciousness accompanied by headache, vomiting, weakness in the upper limbs and sensitive disorders. The patient was hospitalized to the intensive care unit and examined for subarachnoid hemorrhage. MRI of the head and cervical spine and direct invasive angiography were performed. Perimedullary AVF of cervical spinal cord was diagnosed. Complete clinical regression was observed within a month. Microsurgical removal of AVF was performed in scheduled fashion. Postoperative follow-up period was over 6 months.

Predictors of an academic career among fellowship-trained open vascular and endovascular neurosurgeons

OBJECTIVE

Although previous studies have explored factors that predict an academic career among neurosurgery residents in general, such predictors have yet to be determined within specific neurosurgical subspecialties. The authors report on predictors they identified as correlating with academic placement among fellowship-trained vascular neurosurgeons.

METHODS

A database was created that included all physicians who graduated from ACGME (Accreditation Council for Graduate Medical Education)-accredited neurosurgery residency programs between 1960 and 2018 using publicly available online data. Neurosurgeons who completed either open vascular or endovascular fellowships were identified. Subsequent employment of vascular or endovascular neurosurgeons in academic centers was determined. A position was considered academic if the hospital of employment was affiliated with a neurosurgery residency program; all other positions were considered non-academic. Bivariate analyses were conducted using Fisher's exact test or the Mann-Whitney U-test, and multivariate analysis was performed using a logistic regression model.

RESULTS

A total of 83 open vascular neurosurgeons and 115 endovascular neurosurgeons were identified. In both cohorts, the majority of neurosurgeons were employed in academic positions after training. In bivariate analysis, only 2 factors were significantly associated with a career in academic neurosurgery for open vascular neurosurgeons: 1) an h-index of ≥ 2 during residency (OR 3.71, p = 0.016), and 2) attending a top 10 residency program based on U.S. News and World Report rankings (OR 4.35, p = 0.030). In bivariate analysis, among endovascular neurosurgeons, having an h-index of ≥ 2 during residency (OR 4.35, p = 0.0085) and attending a residency program affiliated with a top 10 U.S. News and World Report medical school (OR 2.97, p = 0.029) were significantly associated with an academic career. In multivariate analysis, for both open vascular and endovascular neurosurgeons, an h-index of ≥ 2 during residency was independently predictive of an academic career. Attending a residency program affiliated with a top 10 U.S. News and World Report medical school independently predicted an academic career among endovascular neurosurgeons only.

CONCLUSIONS

The authors report that an h-index of ≥ 2 during residency predicts pursuit of an academic career among vascular and endovascular neurosurgeons. Additionally, attendance of a residency program affiliated with a top research medical school independently predicts an academic career trajectory among endovascular neurosurgeons. This result may be useful to identify and mentor residents interested in academic vascular neurosurgery.

Application of Fluorescein Fluorescence in Vascular Neurosurgery

Background: Fluorescein sodium (FNa) is a fluorescent drug with a long history of use for assessing retinal blood flow in ophthalmology; however, its application in vascular neurosurgery is only now gaining popularity. This review summarizes the current knowledge about using FNa videoangiography in vascular neurosurgery.

Methods: We performed a literature review on the usage of FNa for fluorescent videoangiography procedures in neurosurgery. We analyzed methods of injection, dosages of FNa, visualizing platforms, and interpretation of FNa videoangiography. We also reviewed practical applications of FNa videoangiography during various vascular neurosurgeries.

Results: FNa videoangiography can be performed with intraarterial (intracarotid) or intravenous dye injections. Both methods provide excellent resolution with enhanced fluorescence that shows intravascular blood flow on top of visible surrounding anatomy, and both allow simultaneous purposeful microsurgical manipulations. Although it is invasive, an intracarotid FNa injection results in faster contrast appearance and higher-intensity fluorescence and requires a lower dose per injection (reported range, 1–50 mg) compared with peripheral intravenous FNa injection (reported range, 75–2,000 mg or 1–1.5 mg/kg body weight). Four optical excitation/detection tools for FNa videoangiography have been successfully used: conventional xenon-light operating microscope with a special filter set, pencil-type light-emitting diode probe with a filter set, laser-illumination operating microscope, and an endoscope with a filter set. FNa videoangiography was reported to be feasible and useful in various clinical scenarios, such as examining the feeders and drainers in arteriovenous malformation surgery, checking the patency of a microvascular anastomosis, and assessing blood flow during aneurysm clipping. FNa videoangiography can be repeated during the same procedure and used along with indocyanine green (ICG) videoangiography.

Conclusions: Compared with ICG videoangiography, FNa videoangiography has the advantages of enabling real-time inspection and better visualization at deep locations; however, thick vessel walls limit visualization of FNa in larger vessels. FNa videoangiography is a useful tool in multiple neurovascular scenarios and merits further studies to establish its clinical value.

Long-term patency in cerebral revascularization surgery: an analysis of a consecutive series of 430 bypasses

OBJECTIVE

Large cohort analysis concerning intracerebral bypass patency in patients with long-term follow-up (FU) results is rarely reported in the literature. The authors analyzed the long-term patency of extracranial-to-intracranial (EC-IC) and intracranial-to-intracranial (IC-IC) bypass procedures.

METHODS

All intracranial bypass procedures performed between 1997 and 2017 by a single surgeon were screened. Patients with postoperative imaging (CT angiography, MR angiography, or catheter angiography) were included and grouped into immediate (< 7 days), short-term (7 days-1 year), and long-term (> 1 year) FU groups. Data on patient demographics, bypass type, interposition graft type, bypass indication, and radiological patency were collected and analyzed with univariate and multivariate (adjusted multiple regression) models.

RESULTS

In total, 430 consecutive bypass procedures were performed during the study period (FU time [mean ± SD] 0.9 ± 2.2 years, range 0-17 years). Twelve cases were occluded at FU imaging, resulting in an overall cumulative patency rate of 97%. All bypass occlusions occurred within a week of revascularization. All patients in the short-term FU group (n = 76, mean FU time 0.3 ± 0.3 years) and long-term FU group (n = 89, mean FU time 4.1 ± 3.5 years) had patent bypasses at last FU. Patients who presented with aneurysms had a lower rate of patency than those with moyamoya disease or chronic vessel occlusion (p = 0.029). Low-flow bypasses had a significantly higher patency rate than high-flow bypasses (p = 0.033). In addition, bypasses with one anastomosis site compared to two anastomosis sites showed a significantly higher bypass patency (p = 0.005). No differences were seen in the patency rate among different grafts, single versus bilateral, or between EC-IC and IC-IC bypasses.

CONCLUSIONS

The overall bypass patency of 97% indicates a high likelihood of success with microsurgical revascularization. Surgical indication (ischemia), low-flow bypass, and number of anastomosis (one site) were associated with higher patency rates. EC-IC and IC-IC bypasses have comparable patency rates, supporting the use of intracranial reconstructive techniques. Bypasses that remain patent 1 week postoperatively and have the opportunity to mature have a high likelihood of remaining patent in the long term. In experienced hands, cerebral revascularization is a durable treatment option with high patency rates.

Infrared thermography brain mapping surveillance in vascular neurosurgery for anterior communicating artery aneurysm clipping

Background:

Infrared thermography (IT) is a noninvasive, real-time diagnostic method that requires no contact with the patient and has a broad spectrum of potential applications in neurosurgery. It has been previously demonstrated the high sensitivity and specificity that IT has to detect brain blood flow changes.

Case Description:

The case is based on a 64-year-old diabetic and hypertensive male, to whom an anterior communicating artery (ACoA) incidental aneurysm was discovered. We performed the basal infrared thermography mapping (ITM) and immediately after the transitory clip placement in both A1 segments of the anterior cerebral artery (A1-ACA), we performed a second ITM of the exposed brain cortex. After the definitive clip placement in the neck of the ACoA aneurysm, we removed the transitory clips of both A1-ACA and performed a third ITM of the cortical surface, without finding any cortical cooling or significative temperature differences (Ϫt) compared to the basal ITM. The postoperatory computed tomography (CT) and angio-CT did not show any ischemic damage and confirmed the accurate aneurysm clipping.

Conclusions:

The ITM seems to be a real-time, safe, and useful brain mapping method to identify different temperature zones and temperature dispersion gradients in the human brain cortex. More studies are needed to evaluate the potential applications of IT mapping of the human brain and its use in neurosurgery and vascular neurosurgery.

Magnetic resonance susceptibility weighted imaging in neurosurgery: current applications and future perspectives

Susceptibility weighted imaging (SWI) is a relatively new imaging technique. Its high sensitivity to hemorrhagic components and ability to depict microvasculature by means of susceptibility effects within the veins allow for the accurate detection, grading, and monitoring of brain tumors. This imaging modality can also detect changes in blood flow to monitor stroke recovery and reveal specific subtypes of vascular malformations. In addition, small punctate lesions can be demonstrated with SWI, suggesting diffuse axonal injury, and the location of these lesions can help predict neurological outcome in patients. This imaging technique is also beneficial for applications in functional neurosurgery given its ability to clearly depict and differentiate deep midbrain nuclei and close submillimeter veins, both of which are necessary for presurgical planning of deep brain stimulation. By exploiting the magnetic susceptibilities of substances within the body, such as deoxyhemoglobin, calcium, and iron, SWI can clearly visualize the vasculature and hemorrhagic components even without the use of contrast agents. The high sensitivity of SWI relative to other imaging techniques in showing tumor vasculature and microhemorrhages suggests that it is an effective imaging modality that provides additional information not shown using conventional MRI. Despite SWI's clinical advantages, its implementation in MRI protocols is still far from consistent in clinical usage. To develop a deeper appreciation for SWI, the authors here review the clinical applications in 4 major fields of neurosurgery: neurooncology, vascular neurosurgery, neurotraumatology, and functional neurosurgery. Finally, they address the limitations of and future perspectives on SWI in neurosurgery.

Factors that predict hydrocephalus following intraventricular hemorrhage

OBJECTIVE

To evaluate potential risk factors that can predict the development of hydrocephalus (HCP) in adult patients with intraventricular hemorrhage (IVH).

METHODS

Retrospective analysis of all adult patients presented to King Fahad Medical City between 2004 and 2011 with intraventricular hemorrhage to evaluate different variables and their association with HCP.

RESULTS

A total of 31 patients were included in the study, 14 patients (45.16%) developed HCP. Seventy-four percent of HCP patients (10 out of 14) had Graeb classification of ≥6 and/or had IVH affecting all ventricles, while 76% of the patients without HCP (13 out of 17) had a Graeb classification of <6 and/or had IVH only in the lateral ventricles (8 out of 17) or lateral ventricles and either third or fourth ventricle (5 out of 17). Statistical analysis showed that HCP is significantly associated with both Graeb classification of 6 or greater number of IVH affecting all ventricles and 3 versus 1-2 affected ventricles; (OR (95% CI, p value), respectively, 19.3(2, >20), p value<0.05; 8.5 (1.6, >30), p value<0.05.

CONCLUSION

HCP following IVH is present in approximately half of all IVH cases. In the present retrospective study, it was found that patients with higher grades of IVH and/or a greater number of affected ventricles had a greater risk of developing HCP.