Evidence-based guideline update: intraoperative spinal monitoring with somatosensory and transcranial electrical motor evoked potentials: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and the American Clinical Neurophysiology Society.

OBJECTIVE: To evaluate whether spinal cord intraoperative monitoring (IOM) with somatosensory and transcranial electrical motor evoked potentials (EPs) predicts adverse surgical outcomes. METHODS: A panel of experts reviewed the results of a comprehensive literature search and identified published studies relevant to the clinical question. These studies were classified according to the evidence-based methodology of the American Academy of Neurology. Objective outcomes of postoperative onset of paraparesis, paraplegia, and quadriplegia were used because no randomized or masked studies were available. RESULTS AND RECOMMENDATIONS: Four Class I and 8 Class II studies met inclusion criteria for analysis. The 4 Class I studies and 7 of the 8 Class II studies reached significance in showing that paraparesis, paraplegia, and quadriplegia occurred in the IOM patients with EP changes compared with the IOM group without EP changes. All studies were consistent in showing all occurrences of paraparesis, paraplegia, and quadriplegia in the IOM patients with EP changes, with no occurrences of paraparesis, paraplegia, and quadriplegia in patients without EP changes. In the Class I studies, 16%-40% of the IOM patients with EP changes developed postoperative-onset paraparesis, paraplegia, or quadriplegia. IOM is established as effective to predict an increased risk of the adverse outcomes of paraparesis, paraplegia, and quadriplegia in spinal surgery (4 Class I and 7 Class II studies). Surgeons and other members of the operating team should be alerted to the increased risk of severe adverse neurologic outcomes in patients with important IOM changes (Level A).

The US health care system: Part 1: Our current system.

The US health care crisis is of great concern to American neurologists. The United States has the world's most expensive health care system yet one-sixth of Americans are uninsured. The cost and volume of procedures is expanding, while reimbursement for office visits is declining. Pharmaceutical costs, durable goods, and home health care are growing disproportionately to other services. Carriers spend more for their own administration and profit than on payments to physicians. This first article on the US health care system identifies problems and proposes solutions, many of which are championed by the American Academy of Neurology through its legislative and regulatory committees.

Invited article: the US health care system: part 2: proposals for improvement and comparison to other systems.

In the search for a universal, high quality, affordable health care system, Americans seek to identify and correct a series of current problems. In part one of this two-part series, we presented problems along with some suggested actions. This second part presents other health care systems in Europe and Canada. These different systems provide universal care and at a lower cost than in the United States. Further domestic proposals are presented from the Massachusetts plan and positions from US presidential candidates. These systems and proposals raise ideas about possible changes in the US health care system. Knowledge of these issues and other health care systems will help foster a meaningful dialog about changes in the US health care system.

Acute seizures after intracerebral hemorrhage: a factor in progressive midline shift and outcome.

OBJECTIVE: To determine whether early seizures that occur frequently after intracerebral hemorrhage (ICH) lead to increased brain edema as manifested by increased midline shift. METHODS: A total of 109 patients with ischemic stroke (n = 46) and intraparenchymal hemorrhage (n = 63) prospectively underwent continuous EEG monitoring after admission. The incidence, timing, and factors associated with seizures were defined. Serial CT brain imaging was conducted at admission, 24 hours, and 48 to 72 hours after hemorrhage and assessed for hemorrhage volume and midline shift. Outcome at time of discharge was assessed using the Glasgow Outcome Scale score. RESULTS: Electrographic seizures occurred in 18 of 63 (28%) patients with ICH, compared with 3 of 46 (6%) patients with ischemic stroke (OR = 5.7, 95% CI 1.4 to 26.5, p < 0.004) during the initial 72 hours after admission. Seizures were most often focal with secondary generalization. Seizures were more common in lobar hemorrhages but occurred in 21% of subcortical hemorrhages. Posthemorrhagic seizures were associated with neurologic worsening on the NIH Stroke Scale (14.8 vs 18.6, p < 0.05) and with an increase in midline shift (+ 2.7 mm vs -2.4 mm, p < 0.03). There was a trend toward increased poor outcome (p < 0.06) in patients with posthemorrhagic seizures. On multivariate analysis, age and initial NIH Stroke Scale score were independent predictors of outcome. CONCLUSION: Seizures occur commonly after ICH and may be nonconvulsive. Seizures are independently associated with increased midline shift after intraparenchymal hemorrhage.

A profile of neurology practice based on Medicare services: an AAN Medical Economics and Management Committee report. American Academy of Neurology.

OBJECTIVE: This report uses Medicare data to provide insight into the patient care services most often provided by neurologists. METHODS: The 1998 Medicare data set for physician services was obtained from the Health Care Financing Administration. Neurologists' services were tabulated and compared to the 1998 American Academy of Neurology Member Demographic and Practice Characteristics Report. A profile was derived of neurologists' typical services. RESULTS: Patient visits represent 70% of neurologists' services when evaluated by income. Office was the site of service for 62% of patient visit income. Established patients were 29% of patient visit income. Neurologists frequently code patient visits at levels of service higher than used by other physicians. EMG and nerve conduction velocity together represent 55% of neurodiagnostic services when evaluated by income. CONCLUSIONS: Patient care continues to be the main service of neurologists, with office care more than hospital care. Established patient care is an important part of patient services, confirming the role of the neurologist in principal care. Neurologists' patient care levels of service are higher than for other physicians.

Spinal cord monitoring.

Over the past two decades, intraoperative spinal cord monitoring has matured into a widely used clinical tool. It is used when the spinal cord is at risk for damage during a surgical procedure. This includes orthopedic, neurosurgical, and certain cardiothoracic procedures. Both somatosensory evoked potential (SEP) and direct motor pathway stimulation techniques are available. The SEP techniques are used most widely, are generally accepted, and have been shown to reduce surgical morbidity. A large multicenter study has shown that SEP monitoring reduces postoperative paraplegia by more than 50-60%. Techniques and literature on clinical applications are reviewed in this report.

Increased incidence and impact of nonconvulsive and convulsive seizures after traumatic brain injury as detected by continuous electroencephalographic monitoring.

OBJECT: The early pathophysiological features of traumatic brain injury observed in the intensive care unit (ICU) have been described in terms of altered cerebral blood flow, altered brain metabolism, and neurochemical excitotoxicity. Seizures occur in animal models of brain injury and in human brain injury. Previous studies of posttraumatic seizures in humans have been based principally on clinical observations without a systematic approach to electroencephalographic (EEG) recording of seizures. The purpose of this study was to determine prospectively the incidence of convulsive and nonconvulsive seizures by using continuous EEG monitoring in patients in the ICU during the initial 14 days post-injury. METHODS: Ninety-four patients with moderate-to-severe brain injuries underwent continuous EEG monitoring begin-ning at admission to the ICU (mean delay 9.6+/-5.4 hours) and extending up to 14 days postinjury. Convulsive and nonconvulsive seizures occurred in 21 (22%) of the 94 patients, with six of them displaying status epilepticus. In more than half of the patients (52%) the seizures were nonconvulsive and were diagnosed on the basis of EEG studies alone. All six patients with status epilepticus died, compared with a mortality rate of 24% (18 of 73) in the nonseizure group (p<0.001). The patients with status epilepticus had a shorter mean length of stay (9.14+/-5.9 days compared with 14+/-9 days [t-test, p<0.031). Seizures occurred despite initiation of prophylactic phenytoin on admission to the emergency room, with maintenance at mean levels of 16.6+/-2.8 mg/dl. No differences in key prognostic factors (such as the Glasgow Coma Scale score, early hypoxemia, early hypotension, or 1-month Glasgow Outcome Scale score) were found between the patients with seizures and those without. CONCLUSIONS: Seizures occur in more than one in five patients during the 1st week after moderate-to-severe brain injury and may play a role in the pathobiological conditions associated with brain injury.

Continuous EEG monitoring in the intensive care unit: early findings and clinical efficacy.

The assessment of the neurocritical care patient involves serial assessment of neurologic status using bedside clinical examination and a variety of periodic neurophysiologic testing. Continuous electroencephalographic (CEEG) monitoring in the intensive care unit offers a unique means to track neurologic function directly and regionally. CEEG is becoming more widespread with a growing but small body of literature. The purpose of this paper is to outline the current experience with intensive care unit CEEG monitoring. The basic methods and caveats are discussed. We review the underlying rationale for using CEEG which is that secondary neurologic injury commonly occurs in the intensive care unit and at times is hard to detect. CEEG has a proven role in detecting secondary injuries, namely seizures and brain ischemia. The basic tenets of establishing clinical effectiveness for CEEG in the ICU are discussed while acknowledging a need for further study of clinical effectiveness. We review our initial clinical experience of CEEG in 300 patients and outline the clinical efficacy in terms of cost reduction and improvement in outcome (P < 0.01) using CEEG. Finally, several controversial aspects of CEEG are enumerated, and the need for additional study to answer these pressing questions is presented.

Pentoxifylline is not a promising treatment for multiple sclerosis in progression phase.

Fourteen MS patients took pentoxifylline at varying doses for up to 24 months. In vitro production of tumor necrosis factor alpha was reduced in patients taking 2,400 to 3,200 mg/day of pentoxifylline for 12 weeks or more. Twelve of the 14 patients experienced worsening of the disease during the study according to clinical, MRI, or visual evoked potential criteria. These results provide no hint of efficacy for pentoxifylline as a treatment for MS in progression phase.

Fundamentals of evoked potentials and common clinical applications today.

Visual, auditory and somatosensory evoked potentials are commonly used in neurology today to confirm and localize sensory abnormalities, to identify silent lesions and to monitor changes. Methods have become standardized. Normal limits are now well described. Published reports have described well how these evoked potentials are different in various types of neurologic disorder. Intensive care unit applications and surgical monitoring have also developed appropriate medical uses of these tests. Evoked potentials have become useful as they are relatively objective, reproducible, very sensitive to impairment and relatively easy to use in many clinical settings.