Deep Hypothermic Circulatory Arrest for Complex Cerebral Aneurysms: Lessons Learned

Endovascular management of large and giant intracranial aneurysms: Experience from a tertiary care neurosurgery institute in India

Objective

With the development of endovascular technique and devices, large and giant intracranial aneurysms are increasingly being managed by this less invasive method. Here we discuss our experience on managing such aneurysms via endovascular technique.

Methods

Retrospective data on 42 patients with large and giant intracranial aneurysms managed by endovascular techniques between September 2015 to December 2017 at our neurosurgery institute were included in this analysis.

Results

There were a total 42 patients with 9 giant and 33 large aneurysms in this study. Eight aneurysms were treated by parent vessel occlusion, 22 aneurysms with coils and rest 12 aneurysms were treated with stent assisted coiling. Following the procedure, Raymond class I occlusion was accomplished in 31 (73.8%) patients while class Ⅱ in 9 (21.4%) and class Ⅲ in 2 (4.8%) patients. Overall morbidity and mortality were 9.5% and 14.3% respectively and favorable outcome was seen in 80.9% patients. Significant correlation was observed with clinical outcome and initial neurological status.

Conclusions

The study indicates that endovascular intervention is a safe and effective method in managing large and giant intracranial aneurysms with lesser morbidity and mortality.

Endovascular selective hypothermia facilitates giant aneurysm clipping: illustrative case

BACKGROUND

The authors present a case of selective hypothermia used for neuroprotection during clipping of a giant partially thrombosed middle cerebral artery (MCA) aneurysm. Although these cases have traditionally required deep hypothermic cardiac arrest, this case illustrates a novel and entirely endovascular solution that avoids cardiac standstill and whole-body cooling.

OBSERVATIONS

This is, to the authors' knowledge, the first case in human surgery of a catheter-based selective hypothermic circuit used to facilitate MCA trapping for almost 30 minutes. Core temperatures never dropped below 34°C, and the patient recovered uneventfully and has been well for over 5 years.

LESSONS

The technical nuances and physiological changes unique to selective hypothermia are discussed.

Endovascular Temporary Balloon Occlusion for Microsurgical Clipping of Posterior Circulation Aneurysms

Based on the relationship between the posterior clinoid process and the basilar artery (BA) apex it may be difficult to obtain proximal control of the BA using temporary clips. Endovascular BA temporary balloon occlusion (TBO) can reduce aneurysm sac pressure, facilitate dissection/clipping, and finally lower the risk of intraoperative rupture. We present our experience with TBO during aneurysm clipping of posterior circulation aneurysms within the setting of a hybrid operating room (hOR). We report one case each of a basilar tip, posterior cerebral artery, and superior cerebellar artery aneurysm that underwent surgical occlusion under TBO within an hOR. Surgical exposure of the BA was achieved with a pterional approach and selective anterior and posterior clinoidectomy. Intraoperative digital subtraction angiography (iDSA) was performed prior, during, and after aneurysm occlusion. Two patients presented with subarachnoid hemorrhage and one patient presented with an unruptured aneurysm. The intraluminal balloon was inserted through the femoral artery and inflated in the BA after craniotomy to allow further dissection of the parent vessel and branches needed for the preparation of the aneurysm neck. No complications during balloon inflation and aneurysm dissection occurred. Intraoperative aneurysm rupture prior to clipping did not occur. The duration of TBO varied between 9 and 11 min. Small neck aneurysm remnants were present in two cases (BA and PCA). Two patients recovered well with a GOS 5 after surgery and one patient died due to complications unrelated to surgery. Intraoperative TBO within the hOR is a feasible and safe procedure with no additional morbidity when using a standardized protocol and setting. No relevant side effects or intraoperative complications were present in this series. In addition, iDSA in an hOR facilitates the evaluation of the surgical result and 3D reconstructions provide documentation of potential aneurysm remnants for future follow-up.

Exploiting sequence labeling framework to extract document-level relations from biomedical texts

Background

Both intra- and inter-sentential semantic relations in biomedical texts provide valuable information for biomedical research. However, most existing methods either focus on extracting intra-sentential relations and ignore inter-sentential ones or fail to extract inter-sentential relations accurately and regard the instances containing entity relations as being independent, which neglects the interactions between relations. We propose a novel sequence labeling-based biomedical relation extraction method named Bio-Seq. In the method, sequence labeling framework is extended by multiple specified feature extractors so as to facilitate the feature extractions at different levels, especially at the inter-sentential level. Besides, the sequence labeling framework enables Bio-Seq to take advantage of the interactions between relations, and thus, further improves the precision of document-level relation extraction.

Results

Our proposed method obtained an F1-score of 63.5% on BioCreative V chemical disease relation corpus, and an F1-score of 54.4% on inter-sentential relations, which was 10.5% better than the document-level classification baseline. Also, our method achieved an F1-score of 85.1% on n2c2-ADE sub-dataset.

Conclusion

Sequence labeling method can be successfully used to extract document-level relations, especially for boosting the performance on inter-sentential relation extraction. Our work can facilitate the research on document-level biomedical text mining.

Postoperative Antiplatelet Therapy in the Treatment of Complex Basilar Apex Aneurysms Implementing Hunterian Ligation and Extracranial-to-Intracranial Bypass: Review of the Literature with an Illustrative Case Report

Large broad-based basilar artery (BA) apex aneurysms involving multiple arterial origins are complex lesions commonly not amenable to direct clipping or endovascular management. BA proximal (Hunterian) occlusion with extracranial-to-intracranial bypass is a supported strategy if 1 or both posterior communicating arteries are small. Hunterian ligation risks sudden aneurysm thrombosis and thromboembolism in the perforator-rich BA apex. There currently exist no guidelines for antiplatelet and anticoagulant therapy after Hunterian ligation for complex BA apex aneurysm treatment. We present a literature review and an illustrative case of an 18-year-old man who presented with progressive headaches and was found to have a large unruptured BA apex aneurysm involving the origins of the bilateral superior cerebellar and posterior cerebral arteries. Given the small posterior communicating arteries and complexity of the aneurysm, proximal BA occlusion with unilateral superficial temporal artery-to-superior cerebellar artery bypass was recommended. Despite antiplatelet treatment with acetylsalicylic acid before and after operation, the patient experienced acute ischemia of the brainstem and cerebellum and an embolic left temporal lobe infarct. The patient received dual antiplatelet therapy starting on postoperative day 6, after which he experienced no new infarcts and made a significant neurologic recovery. The current evidence suggests that proximal BA occlusion in complex BA apex aneurysm cases is thrombogenic and can be especially dangerous if thrombosis occurs suddenly in aneurysms without pre-existing intraluminal thrombus. Dual antiplatelet therapy during the first postoperative week presents a possible strategy for reducing the risk of ischemia due to sudden aneurysm thrombosis.

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

Selective microsurgical treatment of giant intracranial aneurysms

Giant intracranial aneurysms are defined as greater than 25mm in diameter. They share the same surgical challenges and strategies as so-called complex aneurysms, sometimes smaller in size but presenting with similar complex anatomy. The surgical difficulties arise from the size of the sack, the presence of intraluminal thrombus, the thickness of the arterial wall, and the complexity of arterial branching on the neck. Preoperative imaging gathers complementary information from magnetic resonance imaging, computed tomographic angiography, and rotational catheter-based angiography with three-dimensional reconstruction including balloon-test occlusion. The therapeutic decision-making needs a multidisciplinary approach including endovascular, neurosurgical and anesthesiological expertises. The microsurgical treatment needs a step-by-step preoperative planning with anticipation of possible pitfalls and alternative strategies. Classical principles of aneurysm surgery have to be tailored to face the difficulties arising from the size of the sack and from the arterial wall calcifications.

Endovascular treatment of the distal internal carotid artery large aneurysm

Objective

According to the development of endovascular technique and devices, larger aneurysms on the distal internal carotid artery (ICA) can be treated using a less invasive method. The authors report on clinical and angiographic outcomes of these aneurysms treated using an endovascular technique.

Materials and Methods

Data on 21 patients with large aneurysms at distal ICA treated by endovascular method between January 2005 and December 2012 were included in this retrospective analysis.

Results

Clinical outcome of patients showed strong correlation with the initial neurologic status (p < 0.05). Aneurysm morphology showed saccular, fusiform, and wide-neck in 12, six and three patients. Six patients underwent stent assisted coiling and the other 15 patients underwent simple coiling. Aneurysm occlusion was performed immediately after embolization with near-complete (Raymond class 1-2) in 20 patients (95.2%) and incomplete (Raymond class 3) in one patient (4.8%). Delayed thrombotic occlusion occurred in two patients and their clinical result was fatal. Another five patients died in the hospital, from massive brain edema and/or increased intracranial pressure due to initial subarachnoid hemorrhage. Overall mortality was 30% (seven out of 21). Fatal complication related to the endovascular procedure occurred in two patients with thrombosis at middle cerebral artery (one with stent, the other without it).

Conclusion

Recent developed endovascular device and technique is safe enough and a less invasive method for distal large or giant aneurysms. Based on our analysis of the study, we suspect that coil embolization of large distal ICA aneurysms (with or without stenting) is effective and safe.

HEAVEN: The head anastomosis venture Project outline for the first human head transplantation with spinal linkage (GEMINI)

In 1970, the first cephalosomatic linkage was achieved in the monkey. However, the technology did not exist for reconnecting the spinal cord, and this line of research was no longer pursued. In this paper, an outline for the first total cephalic exchange in man is provided and spinal reconnection is described. The use of fusogens, special membrane-fusion substances, is discussed in view of the first human cord linkage. Several human diseases without cure might benefit from the procedure.

The Y-shaped double-barrel bypass in the treatment of large and giant anterior communicating artery aneurysms

Large and giant anterior communicating artery (ACoA) aneurysms usually show partial thrombosis and incorporate both the A1 and A2 segments and crucial perforating vessels. Therefore, direct clip placement or endovascular strategies often fail, leaving cerebral bypass surgery as a relevant therapeutic option. The authors present 3 cases in which a giant or large ACoA aneurysm was successfully occluded using a new technique that applies a double-barrel radial artery bypass. A radial artery graft is modified into a Y-shaped double-barrel conduit. After both pterional and parasagittal craniotomies are carried out, the graft is tunneled between both sites and anastomosed in an end-to-side fashion proximally to either a superficial temporal artery (STA) or M2 branch and distally to bilateral A3 branches. Aneurysm occlusion is then conducted through the pterional or parasagittal craniotomy. In one case, a 42-year-old patient in whom an endovascular approach had failed, the authors performed an STA-A3-A3 bypass and proximal aneurysm occlusion. In two others, a 49-year-old man in whom coiling had failed and a 56-year-old man in whom a giant ACoA aneurysm was partially thrombosed, the authors performed an M2-A3-A3 double-barrel bypass followed by either proximal or distal aneurysm occlusion. Complete aneurysm occlusion with excellent bypass perfusion was documented in the first two cases. In the third case, the authors observed good bypass perfusion with persistent antegrade aneurysm filling, and thus endovascular coil embolization was added to completely occlude the aneurysm.

The Y-shaped double-barrel bypass using a radial artery graft allows for safe and effective occlusion of large and giant ACoA aneurysms that cannot be treated by direct clip application.

Treatment strategies for complex intracranial aneurysms: review of a 12-year experience at the university of cincinnati

Complex intracranial aneurysms (CIAs) include those classified as giant, those located in brain regions of technically difficult access, or that involve arterial trunks/branches, and/or have complicated wall structure. We reviewed retrospectively our management of such lesions in a 12-year period. From 1997 to 2009, 192 patients were admitted with CIAs (133 females, 59 males; average age 55 years); 128 presented with subarachnoid hemorrhage (SAH) and 64 with unruptured, symptomatic CIAs. The SAH group had 73 anterior- and 55 posterior-circulation aneurysms. Most frequent location was middle cerebral artery. Treatment strategies included clipping (65.6%), coiling/stenting (28.1%), bypass (3.1%), no treatment (3.1%). Coiling/stenting was exclusively used for posterior-circulation aneurysms. Outcomes were good (modified Rankin Scale [mRS] 0 to 2) in 54 patients (42.2%), fair (mRS = 3 to 4) in 38 (29.7%), and poor (mRS = 5 to 6) in 36 (28.1%). Among unruptured CIAs, there were 47 anterior- and 17 posterior-circulation aneurysms. Most frequent location was ophthalmic. Thirty (46.9%) were clipped, 19 (29.7%) coiled, 6 (9.4%) by-passed, 2 (3.1%) wrapped, and 7 (10.9%) had no treatment. Outcomes were good in 57 patients (89%) and fair in 7 (11%). Good outcomes were obtained in unruptured CIAs using a multidisciplinary approach. Ruptured CIAs carry a significantly worse prognosis than overall SAH patients.

Dendritic spines and pre-synaptic boutons are stable despite local deep hypothermic challenge and re-warming in vivo

Background and Purpose

Deep hypothermia to 20°C is used clinically for major pediatric and adult surgical procedures. In particular, it is used in the “standstill operation" where blood flow is stopped for up to 30 min. Patients recovering from these procedures can exhibit neurological deficits. Such deficits could arise from changes to dendritic spines and plasticity-induced changes in network function as a result of cooling and/or re-warming. In the brain, each dendritic spine represents a single excitatory synapse and their number can be reflective of injury or plasticity-induced changes in network function. This research sought to determine whether deep hypothermia and re-warming have detrimental effects on synaptic stability and network function.

Methods

In vivo 2-photon (2-P) imaging in green/yellow fluorescent protein (GFP/YFP)-expressing transgenic mice was performed to determine whether 4 hours of deep hypothermia and 2 hours of re-warming can have relatively covert effects on dendritic spine and presynaptic bouton stability. At the same time, electroencephalographic (EEG) activity was recorded to evaluate network function during deep hypothermia and re-warming.

Results

We report that deep hypothermia and subsequent re-warming did not change the stability of dendritic spines or presynaptic boutons in mouse somatosensory cortex measured over 8 hours. As expected, deep hypothermia attenuated ongoing EEG activity over 0.1–80 Hz frequencies. The effects on EEG activity were fully reversible following re-warming.

Conclusion

These results are consistent with deep hypothermia being a safe treatment which could be applied clinically to those undergoing major elective surgical procedures.

Therapeutic hypothermia in acute ischemic stroke

Induced hypothermia has been used for neuroprotection in cardiac and neurovascular procedures. Experimental and translational studies provide evidence for its utility in the treatment of ischemic cerebrovascular disease. Over the past decade, these principles have been applied to the clinical management of acute stroke. Varying induction methods, time windows, clinical indications, and adjuvant therapies have been studied. In this article the authors review the mechanisms and techniques for achieving therapeutic hypothermia in the setting of acute stroke, and they outline pertinent side effects and complications. The manuscript summarizes and examines the relevant clinical trials to date. Despite a reasonable amount of existing data, this review suggests that additional trials are warranted to define the optimal time window, temperature regimen, and precise clinical indications for induction of therapeutic hypothermia in the setting of acute stroke.

Giant intracranial aneurysms: evolution of management in a contemporary surgical series

BACKGROUND

Many significant microsurgical series of patients with giant aneurysms predate changes in practice during the endovascular era.

OBJECTIVE

A contemporary surgical experience is presented to examine changes in management relative to earlier reports, to establish the role of open microsurgery in the management strategy, and to quantify results for comparison with evolving endovascular therapies.

METHODS

During a 13-year period, 140 patients with 141 giant aneurysms were treated surgically. One hundred aneurysms (71%) were located in the anterior circulation, and 41 aneurysms were located in the posterior circulation.

RESULTS

One hundred eight aneurysms (77%) were completely occluded, 14 aneurysms (10%) had minimal residual aneurysm, and 16 aneurysms (11%) were incompletely occluded with reversed or diminished flow. Three patients with calcified aneurysms were coiled after unsuccessful clipping attempts. Eighteen patients died in the perioperative period (surgical mortality, 13%). Bypass-related complications resulted from bypass occlusion (7 patients), aneurysm hemorrhage due to incomplete aneurysm occlusion (4 patients), or aneurysm thrombosis with perforator or branch artery occlusion (4 patients). Thirteen patients were worse at late follow-up (permanent neurological morbidity, 9%; mean length of follow-up, 23 ± 1.9 months). Overall, good outcomes (Glasgow Outcome Score 5 or 4) were observed in 114 patients (81%), and 109 patients (78%) were improved or unchanged after therapy.

CONCLUSION

A heavy reliance on bypass techniques plus indirect giant aneurysm occlusion distinguishes this contemporary surgical experience from earlier ones, and obviates the need for hypothermic circulatory arrest. Experienced neurosurgeons can achieve excellent results with surgery as the "first-line" management approach and endovascular techniques as adjuncts to surgery.

Therapeutic hypothermia: benefits, mechanisms and potential clinical applications in neurological, cardiac and kidney injury

Therapeutic hypothermia involves the controlled reduction of core temperature to attenuate the secondary organ damage which occurs following a primary injury. Clinicians have been increasingly using therapeutic hypothermia to prevent or ameliorate various types of neurological injury and more recently for some forms of cardiac injury. In addition, some recent evidence suggests that therapeutic hypothermia may also provide benefit following acute kidney injury. In this review we will examine the potential mechanisms of action and current clinical evidence surrounding the use of therapeutic hypothermia. We will discuss the ideal methodological attributes of future studies using hypothermia to optimise outcomes following organ injury, in particular neurological injury. We will assess the importance of target hypothermic temperature, time to achieve target temperature, duration of cooling, and re-warming rate on outcomes following neurological injury to gain insights into important factors which may also influence the success of hypothermia in other organ injuries, such as the heart and the kidney. Finally, we will examine the potential of therapeutic hypothermia as a future kidney protective therapy.

Recipient targeting for revascularization using pulsed Doppler ultrasonography for the treatment of an intracranial giant aneurysm

Aneurysmal occlusion after blood flow revascularization is a promising management strategy for the treatment of intracranial giant aneurysms. However, it is necessary to design robust revascularization for preventing postoperative flow-related infarctions caused by abrupt occlusion of the parent vessels. Since direct anastomosis of donor vessels to recipient vessels near giant aneurysms is often difficult, it is preferable to select cortical recipient branches away from the aneurysm, thus providing a sufficient working space for the surgeon. In this paper, the authors' goal was to identify distal cortical recipient arteries on the brain surface, based on pulsed Doppler ultrasonography analysis of blood flow alteration after temporary closure of the efferent vessels. This method is used to visualize the area around the sacrificed vessels, omits intraoperative arteriography or the risk of a surgical trace of the vessels by dissecting the distal sulci, and could be advantageous for necessary and sufficient revascularization.

Surgical management of aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a common and often devastating condition that requires prompt neurosurgical evaluation and intervention. Modern management of aSAH involves a multidisciplinary team of subspecialists, including vascular neurosurgeons, neurocritical care specialists and, frequently, neurointerventional radiologists. This team is responsible for stabilizing the patient on presentation, diagnosing the offending ruptured aneurysm, securing the aneurysm, and managing the patient through a typically prolonged and complicated hospital course. Surgical intervention has remained a definitive treatment for ruptured cerebral aneurysms since the early 1900s. Over the subsequent decades, many innovations in microsurgical technique, adjuvant maneuvers, and intraoperative and perioperative medical therapies have advanced the care of patients with aSAH. This report focuses on the modern surgical management of patients with aSAH. Following a brief historical perspective on the origin of aneurysm surgery, the topics discussed include the timing of surgical intervention after aSAH, commonly used surgical approaches and craniotomies, fenestration of the lamina terminalis, intraoperative neurophysiological monitoring, intraoperative digital subtraction and fluorescent angiography, temporary clipping, deep hypothermic cardiopulmonary bypass, management of acute hydrocephalus, cerebral revascularization, and novel clip configurations and microsurgical techniques. Many of the topics highlighted in this report represent some of the more debated techniques in vascular neurosurgery. The popularity of such techniques is constantly evolving as new studies are performed and data about their utility become available.

Circulatory arrest and deep hypothermia for the treatment of complex intracranial aneurysms--results from a single European center

BACKGROUND

Vascular neurosurgery faces the controversial discussion about the need for deep hypothermia and circulatory arrest (dh/ca) for the treatment of complex cerebral aneurysms. In this retrospective analysis, we present our experience in the treatment of 26 giant and large cerebral aneurysms under profound hypothermia and circulatory arrest.

METHODS

All patients were treated surgically under dh/ca. Seventeen patients had aneurysms of the anterior circulation, and nine patients had aneurysms of the posterior circulation. Thrombosis or calcification was found in ten patients. Eleven patients presented with subarachnoid hemorrhage. The seven patients with the longest circulation arrest time were analyzed in detail.

RESULTS

Subarachnoid hemorrhage led to hospital admission in 42% (n = 11) of cases. The overall mortality was 11.5%, and the overall morbidity was 15%. Ten patients deteriorated transiently but fully recovered. The mean age, Glasgow Coma Score, Fisher, and Hunt and Hess Score correlated significantly with the long-term outcome. Circulation arrest time correlated significantly to the neurological outcome on discharge. All patients with prolonged circulation arrest times had wide aneurysmal necks, and four had adjacent vessels to the dome or the parent vessel included in the neck. We observed a significant increase of neurological deficits immediately postoperatively, but this neurological deterioration resolved over time.

CONCLUSIONS

We observed neurological deterioration immediately postoperatively in 13 patients, but all patients fully recovered within 6 months except for four patients. A long cardiac arrest time reflected complex pathoanatomical conditions. We conclude that the clipping procedure under deep hypothermia and circulatory arrest remains a pivotal armament in complex vascular neurosurgery.

Impact of hypothermia in the rural, pediatric trauma patient

OBJECTIVE

Hypothermia is an independent predictor of mortality in adult trauma studies. However, the impact of hypothermia on the pediatric trauma population has not been described. The purpose of this study is to evaluate hypothermia as a cofactor to mortality, complications, and among survivors, hospital length of stay parameters in the pediatric trauma population.

DESIGN

Retrospective review of a prospectively collected database (National Trauma Registry of the American College of Surgeons) over a 5-yr period (July 2002 to June 2007).

SETTING

A rural, level I trauma center.

PATIENTS

One thousand six hundred twenty-nine pediatric patients admitted with a traumatic injury.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Multivariate regression models were used to evaluate the association of hypothermia with mortality, infectious complications, organ dysfunction, and among survivors, hospital length of stay parameters. Of 1,629 pediatric trauma patients admitted, 182 (11.1%) patients were hypothermic (temperature below 36 degrees C) on admission. Hypothermia had an adjusted odds ratio (AOR) of 2.41 (95% confidence interval [CI], 1.12-5.22, p = .025) for mortality. After controlling for covariates, hypothermia had associations with developing pneumonia (AOR, 0.185, 95% CI, 0.040-0.853; p = .031) and a bleeding diathesis (AOR, 3.14, 95% CI, 1.04-9.44; p = .042). The median days in the hospital, intensive care unit (ICU), and ventilator were longer in the hypothermic cohort; however, after controlling for covariates, hypothermia was not associated with differences in hospital days, ICU days, or ventilator days.

CONCLUSIONS

Hypothermia is a common problem at admission among pediatric trauma patients. Hypothermia is associated with an increase in the odds of death and the development of a bleeding diathesis, while having decreased odds for developing pneumonia. While the length of stay indicators were longer in the hypothermic cohort among survivors, no significant association was noted with hypothermia for hospital, ICU, or ventilator days after controlling for confounders.

Temporary balloon occlusion during the surgical treatment of giant paraclinoid and vertebrobasilar aneurysms

PURPOSE

We propose the combined neurosurgical-endovascular treatment with the balloon occlusion of parent artery during surgery of giant paraclinoid and vertebrobasilar aneurysms, which are unsuitable for a pure endovascular or surgical approach.

METHODS

Between January 2003 and December 2007, we treated surgically 15 giant aneurysms (11 paraclinoid and four vertebrobasilar) with the combined approach of surgery and endovascular intraoperative technique.

FINDINGS

Complete aneurysm occlusion was achieved in all 15 aneurysms, as confirmed by intraoperative angiographic control. In one paraclinoid aneurysm, a small recurrence became evident 1 year after surgery and needed coil embolisation.

CONCLUSIONS

The temporary balloon occlusion technique is useful and improves the safety of the unavoidable exposure of the parent artery in the surgical treatment of giant paraclinoid and vertebrobasilar aneurysms.

Impact of hypothermia (below 36 degrees C) in the rural trauma patient

BACKGROUND

Hypothermia is an independent predictor of mortality based on urban studies. But this association has not been described in the rural setting. This study's purpose was to evaluate hypothermia as a cofactor to mortality, complications, and hospital length of stay (LOS) parameters in the rural trauma setting.

STUDY DESIGN

The National Trauma Registry of the American College of Surgeons database for our rural, Level I trauma center was queried for a 5-year period (July 2002 to June 2007) to identify adult trauma patients. Multivariate regression models were used to evaluate the association of hypothermia with mortality; infectious complications; organ dysfunction; and, among survivors, hospital LOS parameters.

RESULTS

Of 9,482 adult patients admitted, 1,490 (15.7%) patients were hypothermic. Hypothermia had an adjusted odds ratio of 1.70 for mortality (95% CI, 1.35 to 2.12; p < 0.001). After controlling for covariates, hypothermia was not significantly associated with infectious complications or organ dysfunction, except for arrhythmia (adjusted odds ratio, 1.40; CI, 1.03 to 1.90; p = 0.031). Hypothermia was not associated with a difference in ICU (p = 0.310) or ventilator (p = 0.144) LOS. But a slight increase in hospital days was noted in the hypothermic patient (hazards ratio, 0.890 for discharge; 95% CI, 0.838 to 0.946; p < 0.001).

CONCLUSIONS

Hypothermia is a common problem at admission in a rural trauma center. It is associated with an increase in hospitalized days but not with increased ICU or ventilator days among survivors. Other than arrhythmias, it was not significantly associated with other National Trauma Registry of the American College of Surgeons infectious or organ dysfunction complications. Hypothermia is an independent risk factor for mortality in the rural trauma patient.

Perioperative hypothermia: use and therapeutic implications

Perioperative cerebral ischemic insults are common in some surgical procedures. The notion that induced hypothermia can be employed to improve outcome in surgical patients has persisted for six decades. Its principal application has been in the context of cardiothoracic and neurosurgery. Mild (32-35 degrees C) and moderate (26-31 degrees C) hypothermia have been utilized for numerous procedures involving the heart, but intensive research has found little or no benefit to outcome. This may, in part, be attributable to confounding effects associated with rewarming and lack of understanding of the mechanisms of injury. Evidence of efficacy of mild hypothermia is absent for cerebral aneurysm clipping and carotid endarterectomy. Deep hypothermia (18-25 degrees C) during circulatory arrest has been practiced in the repair of congenital heart disease, adult thoracic aortas, and giant intracranial aneurysms. There is little doubt of the protective efficacy of deep hypothermia, but continued efforts to refine its application may serve to enhance its utility. Recent evidence that mild hypothermia is efficacious in out-of-hospital cardiac arrest has implications for patients incurring anoxic or global ischemic brain insults during anesthesia and surgery, or perioperatively. Advances in preclinical models of ischemic/anoxic injury and cardiopulmonary bypass that allow definition of optimal cooling strategies and study of cellular and subcellular events during perioperative ischemia can add to our understanding of mechanisms of hypothermia efficacy and provide a rationale basis for its implementation in humans.

Can we improve neurological outcomes in severe traumatic brain injury? Something old (early prophylactic hypothermia) and something new (erythropoietin)

Traumatic brain injury is a leading cause of mortality and long-term morbidity, particularly affecting young people. With our best therapies, one half of the patients with severe traumatic brain injury are never capable of living independently. Two interventions, which have real potential to improve neurological outcomes in patients with traumatic brain injury, are (i) very early induction of prophylactic hypothermia and (ii) exogenous erythropoietin therapy. There is substantial experimental evidence, a plausible biological rationale, and supportive clinical evidence from clinical trials to suggest a possible beneficial effect of prophylactic hypothermia and also for exogenous erythropoietin therapy in severe traumatic brain injury. Despite the recent guidelines and publications recommending these interventions, critical care clinicians should be conservative towards implementing these therapies outside clinical trials due to substantial efficacy and safety concerns. Nevertheless the high morbidity and mortality associated with severe traumatic brain injury (TBI) demands that we investigate the safety and efficacy of these promising potential therapies as a matter of urgency.

Clipping of very large or giant unruptured intracranial aneurysms in the anterior circulation: an outcome study

Object

Patients with very large or giant unruptured intracranial aneurysms present with ischemic stroke and progressive disability. The aneurysm rupture risk in these patients is extreme—up to 50% in 5 years. In this study the authors investigated the outcome of surgical treatment for these very large aneurysms in the anterior circulation.

Methods

Clinical data on 62 patients who underwent surgery for unruptured aneurysms (20–60 mm) between 1998 and 2006 were reviewed.

Results

Complete aneurysm occlusion (100%) was achieved in 90% of cases, near complete occlusion (90–99%) in 5%. The surgical risk in patients younger than 50 years of age was 8% (Glasgow Outcome Scale score of 1 or 3 within 1 year after surgery). In older patients, the risk increased with advancing age.

Conclusions

The treatment of very large or giant unruptured intracranial aneurysms is hazardous and complex and thus best performed only at major cerebrovascular centers with an experienced team of neurosurgeons, interventional neuroradiologists, neurologists, and neuroanesthesiologists. Surgery, with acceptable risks and excellent occlusion rates, is typically the treatment of choice in patients younger than 50 years of age. In older patients, the benefits of endovascular treatment versus surgery versus no treatment must be carefully weighed individually. Minimizing temporary occlusion and the consequent use of intraoperative angiography may help reduce surgical complications.

A new technique allowing prolonged temporary cerebral artery occlusion

OBJECT

Clipping of complex cerebral aneurysms often requires temporary vessel occlusion. The risk of stroke, however, increases exponentially with occlusion time. The authors hypothesized that prolonged temporary occlusion might be tolerated if the occluded vessels were perfused with cold physiological saline solution (CPSS). A low-flow perfusion rate would permit surgical manipulation of an aneurysm distal to the occlusion.

METHODS

To test this hypothesis, the authors temporarily occluded the middle cerebral artery (MCA) with an endovascular catheter in 6 rats. Three animals, the treatment group, were perfused with 5-ml CPSS/hour through the occluding endovascular catheter into the MCA, and the other 3 served as an ischemic control group. In both groups, the catheter was removed after 90 minutes of occlusion. The brain temperature was monitored with a stereotactically placed probe in the caudate-putamen in 2 separate experimental groups (11 animals).

RESULTS

Magnetic resonance imaging perfusion scanning during vessel occlusion confirmed similar reduction of cerebral blood flow during MCA occlusion in both the simple-occlusion and perfusion-occlusion groups. Magnetic resonance imaging diffusion scans performed 24 hours after temporary occlusion revealed infarcts in the ischemic control group of 138.3 +/- 28.0 mm(3) versus 9.9 +/- 9.9 mm(3) in the cold saline group (p < 0.005). A focal cooling effect during perfusion with CPSS was demonstrated (p < 0.05).

CONCLUSIONS

Prolonged temporary cerebral vessel occlusion can be tolerated using superselective CPSS perfusion through an occluding endovascular catheter into the ischemic territory. This technique could possibly be applied in neurosurgery practice to the management of complex intracranial aneurysms.

Surgical management of giant intracranial aneurysms

OBJECTIVES

The natural history of giant intracranial aneurysms is generally morbid. Mortality and morbidity associated with giant aneurysms is also higher than for smaller aneurysms. This study was carried out to assess the demographic profile, presenting features, complications, and outcome after surgical treatment of giant intracranial aneurysms.

PATIENTS AND METHODS

A retrospective review of the medical records of all patients with giant intracranial aneurysms treated in the Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, New Delhi, from January 1995 through June 2007 was performed. The demographic profiles, presenting features, radiological findings, surgical treatments, and outcomes were assessed.

RESULTS

A total of 1412 patients harboring 1675 aneurysms were treated. Out of these, 222 patients had 229 (13.7%) giant aneurysms, and of those, 181 aneurysms in 177 patients were managed surgically while 48 were treated with endovascular therapy. In the patients treated with surgery, common clinical presentations included subarachnoid hemorrhage (SAH) in 110 (62%) cases followed by mass effect in 57 (32%) cases. In patients who presented with SAH, the Hunt and Hess SAH grading was: grade I in 43 (39%), grade II in 40 (36%), grade III in 23 (21%), grade IV in two (2%), and grade V in 2 (2%) patients. One hundred and seven aneurysms (in 103 patients) were treated using direct surgical clipping. Forty-six patients with good collateral circulation were treated by gradual occlusion and ligation of the internal carotid artery (ICA) in the neck with a Silverstone clamp. Another nine patients with good collateral circulation, but persisting symptoms after ICA ligation, required trapping for obliteration of the aneurysm. Eleven patients with poor collateral circulation required extracranial-intracranial (EC-IC) bypass before proximal ICA ligation. A post-operative digital subtraction angiography (DSA) was performed in 118 patients and revealed well-obliterated aneurysm in 106 patients. The total treatment mortality rate was 9%. In the last 5 years, 117 patients were operated on with four operative deaths. Overall, the outcome was excellent in 131 (74.0%), good in 22 (12.4%), and poor in eight (4.5%) cases.

CONCLUSIONS

It is concluded that 14% of all intracranial aneurysms are giant. The most common clinical presentation is SAH followed by features of an intracranial mass lesion. The cavernous ICA is the most common portion of the ICA affected. Direct surgical clipping is a safe and effective method of treatment and should be considered the first line of treatment whenever possible. With proper case selection, optimal radiological evaluation, and appropriate surgical strategy, it is possible to achieve a favorable outcome in almost 90% of the cases.