Trends in the use of pulmonary artery catheterization in the aneurysmal subarachnoid hemorrhage population.

Use of the pulmonary artery catheter (PAC) has been controversial since the late 1980s. Multi-center observational and randomized controlled trials (RCTs) have concluded that PACs fail to decrease mortality. Subsequently, studies have looked for a decline in PAC use that corresponds to the literature and have indeed found that it exists. However, none to date have looked primarily at trends in the aneurysmal subarachnoid hemorrhage (aSAH) population. This study uses the Nationwide Inpatient Sample (NIS) from 2000-2010 to identify trends in PAC use among patients with aSAH. Trend analysis was assessed using a multivariable regression model with a calculation of slope of PAC frequency over time for pre-2005 and post-2005. Trends in mortality and routine discharge were also assessed for the same time period. 363,096 SAH patients were extrapolated using survey weights, of whom 6,988 had a PAC. Over time, PAC use declined, with a significant downward shift in the year 2005. Analyses also showed a decrease in mortality over the same time period. Our results show that PAC use among patients with aSAH decreased from 2000 to 2010. Similar to other studies, the decline appears to be temporally related to RCTs that showed a lack of benefit from PAC. Studies such as these have the potential to influence clinical practice through illumination of shifting opinions and approaches.

Complications of endovascular treatment for acute stroke in the SWIFT trial with solitaire and Merci devices.

BACKGROUND AND PURPOSE: Treatment of patients with ischemic stroke after endovascular treatment requires in-depth knowledge of complications. The goal of this study was to make endovascular treatment for acute ischemic stroke safer through an in-depth review of the major periprocedural complications observed in the Solitaire FR With Intention for Thrombectomy (SWIFT) trial. MATERIALS AND METHODS: The SWIFT data base was searched for major peri-procedural complications defined as symptomatic intracranial hemorrhage within 36 hours, SAH, air emboli, vessel dissection, major groin complications, and emboli to new vascular territories. RESULTS: Major peri-procedural complications occurred in 18 of 144 patients (12.5%) as follows: symptomatic intracranial hemorrhage, 4.9%; air emboli, 1.4%; vessel dissection, 4.2%; major groin complications, 2.8%; and emboli to new vascular territories, 0.7%. Rates of symptomatic intracranial bleeding by subtype were PH1, 0.7%; PH2, 0.7% (PH1 indicates hematoma within ischemic field with some mild space-occupying effect but involving ≤ 30% of the infarcted area; PH2, hematoma within ischemic field with space-occupying effect involving >30% of the infarcted area); intracranial hemorrhage remote from ischemic zone, 0%; intraventricular hemorrhage, 0.7%; and SAH, 3.5%. We did not observe any statistically significant associations of peri-procedural complications with age; type of treatment center; duration of stroke symptoms; NIHSS score, IV thrombolytics, atrial fibrillation, site of vessel occlusion; rescue therapy administered after endovascular treatment; or device. Comparing the Merci with the Solitaire FR retrieval device, we observed symptomatic cerebral hemorrhage (10.9% versus 1.1%; P = .013); symptomatic SAH (7.3% versus 1.1%; P = .07), air emboli (1.8% versus 1.1%; P = 1.0), emboli to new vascular territories (1.8% versus 0%; P = .38), vessel dissection (1.8% versus 4.5%; P = .65), and major groin complications (3.6% versus 7.9%; P = .48). Angiographic vasospasm was common but without clinical sequelae. CONCLUSIONS: Understanding of procedural complications is important for treatment of patients with stroke after endovascular treatment. We observed fewer endovascular complications with the Solitaire FR device treatment compared with Merci device treatment, particularly symptomatic cerebral hemorrhage.

Vagus nerve stimulation for control of intractable seizures in childhood.

Vagus nerve stimulation (VNS) is gaining increasing popularity and credibility as a treatment option for children with intractable epilepsy. VNS offers several advantages over extant treatments. Its efficacy is maintained during prolonged stimulation, and seizure control actually improves with time. There is no associated cognitive impairment and no adverse drug interactions. Unlike cerebral surgery, VNS is a potentially reversible form of therapy. The computer-controlled characteristic of the device permits complete and involuntary treatment compliance. VNS is safe and well-tolerated. Its side effects are generally transient and mild, and no physiologic perturbations have been reported despite extensive monitoring. Serious adverse events are rare, and no deaths have been attributed to VNS therapy itself or to the technique of surgical insertion. In this article, we discuss the theoretical background behind VNS and review the clinical studies that substantiate its long-term safety, feasibility, tolerability and potential efficacy in children with refractory epilepsy.

Microcatheterization of the cervical epidural space via lumbar puncture: technical note.

OBJECTIVE: Deposition of opiates, corticosteroids, or local anesthetics into the epidural space is useful for the management of painful maladies of the cervical and thoracic spine. We describe a novel technique for epidural medication delivery via an angiographic microcatheter inserted at or below the conus and advanced cephalad under fluoroscopic guidance. Unlike commercial kits used by anesthesiologists, this method uses a radiopaque catheter that can be precisely targeted to the levels of interest. The hazards of direct puncture, such as "wet tap" or injury to the cervical cord, are minimized. METHODS: An 18-gauge Tuohy needle is inserted into the lumbar epidural space. A 2.3-French microcatheter and a 0.018-inch steerable guidewire are then introduced through the lumen of the needle. The catheter is fluoroscopically advanced to the cervical epidural space, where Depo-Medrol (Pharmacia & Upjohn, Kalamazoo, MI) is administered. As the catheter is withdrawn, additional corticosteroid can be delivered to the thoracic epidural space, together with long-acting morphine compounds or local anesthetics. Regional pressures within the epidural space and other physiological parameters can be measured, and the local microenvironment can be sampled. RESULTS: To date, we have performed 16 procedures for 13 patients. All patients reported improvement, of varying extent and duration. There have been no complications. CONCLUSION: Our system of accessing the epidural space has many advantages, compared with direct puncture and commercially available kits. It provides a safe means of delivering epidural medication to multiple spinal levels and permits measurement of physiological variables that may be useful in the diagnosis and treatment of cervical and thoracic spine disease.

Percutaneous transpedicular polymethylmethacrylate vertebroplasty for the treatment of spinal compression fractures.

OBJECTIVE: To assess the safety, feasibility, and clinical outcome of percutaneous transpedicular polymethylmethacrylate vertebroplasty (PTPV) for the treatment of spinal compression fractures causing refractory pain. METHODS: We retrospectively reviewed a consecutive group of patients undergoing PTPV at our institution between April 1998 and January 2001. Outcome measures included analgesic requirements, ambulatory status, sleep comfort, and overall quality of life 2 weeks after the procedure. RESULTS: A total of 97 patients (73 women and 24 men) underwent 258 PTPV procedures during 133 treatment sessions. The mean age was 76 years (range, 42-99 yr). The mean duration of follow-up was 14.7 months (range, 2-35 mo). Most of the patients had osteoporotic compression fractures, although some had osteolytic malignancies. Complete follow-up was obtained in 81 patients (84%). Narcotic and analgesic usage decreased in 63% of patients, increased in 7%, and remained the same in 30%. Ambulation and mobility were improved in 51%, worse in 1% and the same in 48%. One-half of the patients were able to sleep more comfortably after the procedure, whereas the other half remained the same. Most patients who reported no change in sleep or ambulation had experienced no impairment of these activities before PTPV. Overall, 74% of patients believed that PTPV significantly enhanced their quality of life and 26% reported no change. No patient was worse after PTPV. One patient with preexisting pneumonia died of respiratory failure after the procedure; another died of an acute stroke weeks later. One patient developed symptomatic pulmonary embolism of cement, and another developed transient quadriceps weakness from radiculopathy. Other complications were minor and infrequent. There were no infections. CONCLUSION: PTPV provided significant relief in a high percentage of patients with refractory pain. PTPV is a safe and feasible treatment for patients with spinal compression fractures.

Percutaneous carotid angioplasty and stenting with the use of gadolinium in lieu of iodinated contrast medium: technical case report and review of the literature.

OBJECTIVE AND IMPORTANCE: We describe a patient who underwent percutaneous transluminal carotid angioplasty and stent placement with the use of intra-arterial gadolinium (Gd-DTPA) instead of iodinated contrast medium. This represents one of the first published reports of the use of Gd-DTPA as an angiographic contrast agent for an interventional neuroradiological procedure. CLINICAL PRESENTATION: A 75-year-old man with renal insufficiency and multiple comorbidities developed amaurosis fugax. Doppler examination revealed high-grade stenosis of the right internal carotid artery. INTERVENTION: The patient underwent percutaneous transluminal balloon angioplasty with endovascular stent placement for 95% narrowing of the proximal right internal carotid artery. Because of his impaired renal function, the procedure was performed with the use of Gd-DTPA as the sole contrast agent. Approximately 60 ml of contrast medium (twice the volume typically used for a magnetic resonance imaging study) was used. There were no neurological, renal, or other complications. CONCLUSION: Intra-arterially administered Gd-DTPA may be substituted for iodinated contrast agents in complex neuroendovascular procedures. This capacity expands the armamentarium for interventional neuroradiological procedures.

Treatment of central nervous system infections: a neurosurgical perspective.

Almost any microorganism has the potential to infect the human central nervous system. Neurosurgical intervention may be required for tissue assay, to establish a microbiologic diagnosis, for decompression of space-occupying lesions with significant mass effects, or for definitive treatments such as cerebrospinal fluid diversion. This article surveys the surgical management of intracranial infections with special emphasis on subdural and epidural empyema, brain abscesses, mycotic aneurysms, and neurocysticercosis.

The development of anatomic art and sciences: the ceroplastica anatomic models of La Specola.

Anatomic models are important heuristic aids for surgeons in training. They are uniquely able to convey the three-dimensional relationships of anatomic structures with a physical immediacy not allowed by any other media. We examine the conceptual development of the anatomic model in light of the history of neuroanatomic understanding and coexistent artistic movements. The teaching anatomic model traces its ancestry to the work of Gaetano Zumbo in the late 17th century, on the heels of important anatomic discoveries made in the preceding 100 years of investigation. The anatomic model reached its peak expression in the late 18th century with the founding of the ceroplastica laboratory in Florence. We discuss the technological, artistic, and scientific origins of the anatomic wax model and the conditions that allowed it to flourish in the late 18th century.

Experience with vagus nerve stimulation for intractable epilepsy: some questions and answers.

Vagus nerve stimulation (VNS) is gaining increasing popularity and credibility as a treatment option for patients with intractable epilepsy. VNS is a relatively recent innovation, however, and like many other incipient developments, it has engendered a number of unresolved controversies and perplexities. Limitations in our current understanding of how VNS works lie at the crux of these uncertainties. In this article, we present our clinical experience with VNS and review the fundamental issue which remain unsettled, such as the mechanism of VNS action, the factors underlying variability in patient outcome, and the selection of ideal candidates for VNS therapy. Although many enigmas persist, VNS has proven to be a safe, feasible, and potentially effective method of reducing seizures in select patient populations. It offers several advantages over extant treatments and, as a result, holds much promise for future therapy of medically refractory epilepsy.

Pathogenesis and pharmacological strategies for mitigating secondary damage in acute spinal cord injury.

OBJECTIVE: Experimental models and clinical observations of acute spinal cord injury (SCI) support the concepts of primary and secondary injury, in which the initial mechanical insult is succeeded by a series of deleterious events that promote progressive tissue damage and ischemia. Whereas the primary injury is fated by the circumstances of the trauma, the outcome of the secondary injury may be amenable to therapeutic modulation. This article reviews the pathogenetic determinants of these two phases of injury and summarizes the pharmacological manipulations that may restore neurological function after SCI. METHODS: Experimental models of SCI and their inherent limitations in simulating human SCI are surveyed. The pathogenesis of primary and secondary injury, as well as the theoretical bases of neurological recovery, are examined in detail. The effects of glucocorticoids, lazeroids, gangliosides, opiate antagonists, calcium channel blockers, glutamate receptor antagonists, antioxidants, free radical scavengers, and other pharmacological agents in both animal models and human trials are summarized. Practical limitations to inducing neural regeneration are also addressed. RESULTS: The molecular events that mediate the pathogenesis of SCI are logical targets for pharmacological manipulation and include glutamate accumulation, aberrant calcium fluxes, free radical formation, lipid peroxidation, and generation of arachidonic acid metabolites. Enhancement of neural regeneration and plasticity comprise other possible strategies. CONCLUSION: Pharmacological agents must be given within a narrow window of opportunity to be effective. Although many therapeutic agents show potential promise in animal models, only methylprednisolone has been shown in large, randomized, double-blinded human studies to enhance the functional recovery of neural elements after acute SCI. Future therapy is likely to involve various combinations of these agents.

Invasive pituitary adenomas: significance of proliferation parameters.

Although most pituitary adenomas behave in a purely benign fashion, microscopic invasion of the subjacent dura is very common, and clinically overt infiltration of the surrounding dura and bone is apparent at intraoperative inspection in about one third of cases. The factors governing invasive behavior remain unknown but are believed to be separate from those regulating cell proliferation. Histological features alone do not distinguish between benign, invasive, and malignant tumors of adenohypophyseal origin. Multiple attempts have been made to identify prognostic markers of aggressive behavior among these tumors. They include cytogenetic analysis of putative tumor suppressor genes or proto-oncogenes as well as immunohistochemical detection of cell-cycle specific antigens. At present, however, these analyses can neither distinguish the indolent pituitary adenoma from one that will pursue an invasive course, nor reliably predict the prognosis in individual patients.

Long-term multicenter experience with vagus nerve stimulation for intractable partial seizures: results of the XE5 trial.

OBJECTIVE: Intermittent stimulation of the left cervical vagus nerve trunk (VNS) with the NeuroCybernetic Prosthesis (NCP) is emerging as a novel adjunct in the management of medically refractory epilepsy. We review the safety and efficacy of VNS 1 year after completion of the E05 study, the largest controlled clinical trial of VNS to date. METHODS: One hundred and ninety-nine patients with intractable epilepsy and at least 6 complex partial or secondarily generalized seizures per month enrolled in a randomized, double-blinded, partial crossover trial of high versus low parameters of stimulation (E05). After 3 months, all patients received high stimulation during an open-label, nonblinded extension trial (XE5). Seizure frequency, adverse events and multiple physiologic variables were monitored at regular intervals. RESULTS: At 3 months, the mean reduction in seizure frequency among patients receiving high stimulation during E05 was 28%. Of the 199 subjects participating in this acute-phase trial, 195 continued in the long-term protocol. Among the latter patients, 21 subsequently exited the study due to lack of efficacy, and 2 others died from causes unrelated to VNS. Complete data were obtained for 164 of the remaining subjects. Using a declining N analysis, the mean and median reduction in seizure frequency at 15 months was 37 and 45%, respectively. A last visit carried forward analysis, which controls for dropouts and incomplete follow-up, yielded comparable results (34 and 45%, respectively), indicating little potential for selection bias. At 15 months, 39% of the subjects had a greater than 50% reduction in seizures, including 21% who had a greater than 75% reduction, and 2% have remained seizure free. Few serious adverse events, physiological perturbation or device failures were reported. CONCLUSIONS: The long-term multicenter safety, efficacy, feasibility and tolerability of VNS, as well as the durability of the NCP device have been confirmed. Unlike chronic therapy with antiepileptic medication, the efficacy of VNS is maintained during prolonged stimulation, and overall seizure control continues to improve with time.

Virtual endoscopic environments in modern neurosurgical practice.

Modern radiographic techniques have allowed the creation of high-definition planar images that can provide important anatomical as well as physiological data. Planar imaging sets can be reformatted into three-dimensional (3-D) data sets that can then be manipulated to demonstrate important anatomical or gross pathological features. Three-dimensional data sets have been used with success in modern image-guided or frameless stereotactic surgery. Another potential application is so-called "virtual endoscopy" or "scopeless endoscopy," in which a 3-D anatomical data set is reformatted into a volume-rendered image that can then be viewed. By reformatting images in this way, a "surgeon's-eye" view can be obtained, which can aid in presurgical planning and diagnosis. The use of virtual endoscopy has the potential to increase our understanding of the appropriate anatomy and the anatomical relationships most apparent during neurosurgical approaches. In so doing, virtual endoscopy may serve as an important means of planning for therapeutic interventions. On the other hand, one must always be cognizant of the technical limitations of these studies regardless of the quality of the reconstructed images. Prospective, correlative, clinical studies in which the anatomical advantages of virtual-based endoscopy are evaluated in large cadaver or patient series must be performed. Until then, the only potential ways to compensate for errors that exist in the algorithms and reconstructions of 3-D endoscopic images are based on the surgeon's understanding of the clinical state of the patient and prior experience with the anatomy in the region of question.

An institutional experience with cervical vagus nerve trunk stimulation for medically refractory epilepsy: rationale, technique, and outcome.

OBJECTIVE: Intermittent stimulation of the left cervical vagus nerve trunk is emerging as a novel adjunct in the treatment of medically refractory seizures. We sought to evaluate theoretical and practical issues attendant to this concept. We review the anatomic and physiological background arguing for clinical application of vagus nerve stimulation, discuss salient aspects of patient selection and the nuances of surgical technique, and present our observations of and results from application of the method. METHODS: Each of 18 patients with medically refractory epilepsy and at least six complex partial or secondarily generalized seizures per month underwent placement of a NeuroCybernetic Prosthesis pulse generator (Cyberonics, Webster, TX) in the chest, connected to helical platinum leads applied to the left cervical vagus nerve trunk. The patients were then randomized in a double-blinded fashion to receive either high (presumably therapeutic) or low (presumably less therapeutic) levels of vagus nerve stimulation. Reduction in seizure frequency, global assessments of quality of life, physiological measurements, and adverse events were recorded during a 3-month period. Patients in the low group were then crossed over to high-stimulation paradigms during a 15-month extension trial. RESULTS: All operations were successful, uneventful, and without adverse postoperative sequelae. One patient was excluded from analysis because of inadequate seizure calendars. Of the seven patients initially assigned to high stimulation, the mean reduction in seizure frequency was 71% at 3 months and 81% at 18 months. Five (72%) of these patients had a greater than 75% reduction in seizure frequency, and one (14%) remained seizure-free after more than 1.5 years of follow-up. The mean reduction in seizure frequency among the low-stimulation group was only 6% at 3 months. No serious complications, device failures, or physiological perturbations occurred. CONCLUSION: In our experience, vagus nerve stimulation has proven to be a safe, feasible, and potentially effective method of reducing seizures in select patient populations. However, the elements of strict definition for the application of the method require further study.

Iatrogenic vertebrobasilar insufficiency after surgery of the subclavian or brachial artery: review of three cases.

OBJECTIVE AND IMPORTANCE: Vertebrobasilar insufficiency resulting from disease of the subclavian artery is well recognized. Usually, this occurs as the "subclavian steal" syndrome in the context of chronic subclavian stenosis and is consequently well tolerated because of collateralization. Acute disruption of the hemodynamics of the aortic arch vessels, however, can produce disastrous sequelae. CLINICAL PRESENTATION: We present three cases of iatrogenic vertebrobasilar insufficiency sustained as complications of surgery of the left subclavian artery or its distal continuation. The cases were chosen from a review of approximately 400 emergency neurosurgery consultations requested at the Los Angeles County Hospital between November 1995 and February 1996. INTERVENTION: The first patient underwent repair of a traumatic brachial artery occlusion and awoke postoperatively with bilateral cortical blindness, right hemiparesis, and multiple cranial nerve deficits that were most likely caused by acute subclavian steal. The second underwent removal of a subclavian embolus and developed bilateral cerebellar infarction leading to persistent coma, possibly from inadvertent embolization of the vertebral artery during surgery. The third underwent resection and bypass grafting of a subclavian aneurysm. Good backflow was reported when the vertebral artery was disarticulated from the subclavian artery, and this vessel was not reimplanted into the graft. The patient suffered massive cerebellar infarction leading rapidly to brain death. CONCLUSION: There are myriad ways in which the inherent redundancy of the vertebrobasilar system may be jeopardized, and when this protective mechanism fails, the results can be disastrous. Flow through the vertebral arteries may be compromised by thrombosis, embolization, dissection, inappropriate ligation, excessive head rotation, hypotension, vasospasm, or acute subclavian steal. These examples illustrate the importance of understanding the complex physiology of posterior fossa circulation as the basis of pre-, intra-, and postoperative management of patients undergoing surgery of the subclavian artery.

The use of oxidized regenerated cellulose in neurosurgical procedures.

The following paper discusses a number of issues relevant to the use of topical hemostatic agents in neurosurgical procedures. We initially describe the basic application of such products and review their relative benefits in neurosurgical interventions, emphasizing the use of oxidized, regenerated cellulose. We then discuss their role in specific operations, such as cortical debridement, cavernous sinus, and other skull base approaches, and aneurysms and arteriovenous malformations of the brain.

Development of an in vitro extracellular matrix assay for studies of brain tumor cell invasion.

Invasion of brain by tumor cells is an inherent feature of the malignant phenotype. Assays to quantitate invasiveness should provide a powerful tool to investigate this phenomenon. We have developed a modified in vitro assay to measure tumor cell invasion, attachment, and chemotaxis using a barrier of the complex basement membrane Matrigel on gelatin-coated filters. Within 5 hours, 7.8% of U251MGp and 2.6% of SF126 human malignant glioma cells invaded the Matrigel and filter, compared with 0.8% of normal human leptomeningeal cells. The extent of invasion was directly proportional to incubation time and filter pore size and inversely proportional to the Matrigel concentration. Cells from exponentially growing U251MGp cultures invaded more readily (10.9%) than cells from plateau-phase cultures (2.3%); however, labeling studies with bromodeoxyuridine showed that quiescent cells and rapidly dividing cells were equally capable of invading. This suggests that the mechanisms underlying invasion by malignant glioma cells are distinct from those underlying proliferation and indicates the need for therapy aimed specifically at invasive behavior. In a practical application of this assay to test a potential anti-invasive strategy, monoclonal antibodies to the beta subunit of an integrin receptor mediating attachment to the extracellular matrix inhibited invasion by U251MGp cells in a dose-dependent manner. This assay should allow evaluation of the cellular and molecular basis of brain tumor progression and perhaps aid the development of rationally designed drugs that limit tumor invasion. It may also allow prediction of the clinical behavior of neoplasms in individual patients.