Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective consecutive case series. OBJECTIVE:To determine predictors of outcome in patients undergoing surgical treatment of spinal dural arteriovenous fistula (SDAVF). SUMMARY OF BACKGROUND DATA/BACKGROUND:Most previous studies assessing postoperative outcome in patients with SDAVF have been limited due to small population size, lack of sufficient information on presurgical variables, or short time of postoperative follow-up. Consequently, the most reliable predictors of functional outcome after treatment of SDAVF are not yet well established. METHODS:Retrospective analysis of consecutive patients with SDAVF treated surgically between June 1985 and March 2008 in our institution. The Aminoff-Logue gait (G) and micturition (M) scores were used to stratify the degree of disability and the G + M score was used as the primary outcome measure. Demographics, clinical presentation, time to diagnosis, fistula level, presurgical motor and sphincter impairment, and magnetic resonance imaging findings were assessed as prognosticators for postoperative outcomes. RESULTS:One hundred fifty-three patients were analyzed. Mean follow-up was 31 ± 36.2 months. Most patients were improved (44%) or stable (34%) upon the last follow-up. Among preoperative variables, worsening weakness with exertion was associated with a better G + M score at the last follow-up (P < 0.001) and presence of pinprick level was associated with a worse G + M score at the last follow-up (P = 0.020). On multivariable analysis, worsening weakness with exertion was associated with better outcome at the last follow-up, and higher G score at presentation and higher G + M score at discharge were associated with worse outcome at the last follow-up. Magnetic resonance images obtained postoperatively for 104 patients (mean, 19.1 ± 22.5 mo) showed complete resolution or improvement of the presurgical T2 signal abnormalities in 83.6% of cases. Changes in postoperative magnetic resonance image and fistula level did not correlate with functional outcomes. CONCLUSION/CONCLUSIONS:The degree of preoperative disability from SDAFV does not determine who will benefit most from surgery and even patients with severe deficits can improve after treatment. Patients with preoperative exertional claudication and without pinprick level on examination have greater chances of postsurgical improvement. LEVEL OF EVIDENCE/METHODS:4.

STUDY DESIGN/METHODS:Retrospective consecutive case series. OBJECTIVE:To assess the symptoms, neurologic signs, and radiologic findings in a large series of patients with myelopathy due to spinal dural arteriovenous fistula (SDAVF). SUMMARY OF BACKGROUND/BACKGROUND:The clinical diagnosis of SDAVF is difficult because presenting symptoms and signs can be similar to those seen with spinal canal stenosis or peripheral nerve or root disorders. METHODS:We reviewed 153 consecutive patients with SDAVF treated surgically at our institution between 1985 and 2008. Before surgery, all patients had detailed neurologic examination, 147 patients had spinal magnetic resonance imaging (MRI) and all but one, had spinal angiography. We evaluated associations between symptoms, physical signs, spinal cord T2 signal abnormality on MRI, and fistula level on angiogram. RESULTS:Mean age was 63.5 years and 119 (77.8%) were men. Weakness and sensory changes are usually symmetric and ascend from the lower extremities. Presenting symptoms included leg weakness (74 patients, 48.4%), leg sensory disturbances (41 patients, 26.8%), pain involving back or legs (31 patients, 20.3%), and sphincter disturbances (6 patients, 3.9%). Worsening weakness with exertion was present in 66 (43.1%) patients and correlated with thoracic fistula location (P=0.04). Pinprick level was identified in 57 (37.3%) patients; L1 level (22.8%) was the most common, followed by T10 (19.3%). Fistula level (±2 levels) corresponded to pinprick level in only 40% of these patients. T2 signal abnormality involved the conus in 95% of our patients. Highest cord level of T2 signal hyperintensity (±2 levels) corresponded to pinprick level in 25% of cases. CONCLUSION/CONCLUSIONS:Leg weakness exacerbated by exercise, likely due to worsening hypertension in the arterialized draining vein, is a common manifestation of thoracic SDAVF. Although a sensory level is often found, it cannot reliably guide the level of imaging. Thus, the entire spine should be examined with MRI when an SDAVF is suspected.

BACKGROUND:Extracorporeal membrane oxygenation (ECMO) may be urgently used as a last resort form of life support when all other treatment options for potentially reversible cardiopulmonary injury have failed. OBJECTIVE:To examine the range and frequency of neurological injury in ECMO-treated adults. DESIGN/METHODS:Retrospective clinicopathological cohort study. SETTING/METHODS:Mayo Clinic, Rochester, Minnesota. PATIENTS/METHODS:A prospectively collected registry of all patients 15 years or older treated with ECMO for 12 or more hours from January 2002 to April 2010. INTERVENTION/METHODS:Patients were analyzed for potential risk factors for neurological events and death using logistic regression and Cox proportional hazards models. MAIN OUTCOME MEASURES/METHODS:Neurological diagnosis and/or death. RESULTS:A total of 87 adults were treated (35 female [40%]; median age, 54 years [interquartile range, 31]; mean duration of ECMO, 91 hours [interquartile range, 100]; overall survival >7 days after ECMO, 52%). Neurological events occurred in 42 patients who received ECMO (50%; 95% confidence interval [CI], 39%-61%). Diagnoses included subarachnoid hemorrhage, ischemic watershed infarctions, hypoxic-ischemic encephalopathy, unexplained coma, and brain death. Death in patients who received ECMO who did not require antecedent cardiopulmonary resuscitation was associated with increased age (odds ratio, 1.24 per decade; 95% CI, 1.03-1.50; P = .02) and lower minimum arterial oxygen pressure (odds ratio, 0.79; 95% CI, 0.68-0.92; P = .03). Although stroke was rarely diagnosed clinically, 9 of 10 brains studied at autopsy demonstrated hypoxic-ischemic and hemorrhagic lesions of vascular origin. CONCLUSION/CONCLUSIONS:Severe neurological sequelae occur frequently in adult ECMO-treated patients with otherwise reversible cardiopulmonary injury (conservative estimate, 50%) and include a range of potentially fatal neurological diagnoses that may be due to the precipitating event and/or ECMO treatment.

OBJECTIVE:Transplant recipients are at risk of developing progressive multifocal leukoencephalopathy (PML), a rare demyelinating disorder caused by oligodendrocyte destruction by JC virus. METHODS:Reports of PML following transplantation were found using PubMed Entrez (1958-July 2010). A multicenter, retrospective cohort study also identified all cases of PML among transplant recipients diagnosed at Mayo Clinic, Johns Hopkins University, Washington University, and Amsterdam Academic Medical Center. At 1 institution, the incidence of posttransplantation PML was calculated. RESULTS:A total of 69 cases (44 solid organ, 25 bone marrow) of posttransplantation PML were found including 15 from the 4 medical centers and another 54 from the literature. The median time to development of first symptoms of PML following transplantation was longer in solid organ vs bone marrow recipients (27 vs 11 months, p = 0.0005, range of <1 to >240). Median survival following symptom onset was 6.4 months in solid organ vs 19.5 months in bone marrow recipients (p = 0.068). Case fatality was 84% (95% confidence interval [CI], 70.3-92.4%) and survival beyond 1 year was 55.7% (95% CI, 41.2-67.2%). The incidence of PML among heart and/or lung transplant recipients at 1 institution was 1.24 per 1,000 posttransplantation person-years (95% CI, 0.25-3.61). No clear association was found with any 1 immunosuppressant agent. No treatment provided demonstrable therapeutic benefit. INTERPRETATION/CONCLUSIONS:The risk of PML exists throughout the posttransplantation period. Bone marrow recipients survive longer than solid organ recipients but may have a lower median time to first symptoms of PML. Posttransplantation PML has a higher case fatality and may have a higher incidence than reported in human immunodeficiency virus (HIV) patients on highly-active antiretroviral therapy (HAART) or multiple sclerosis patients treated with natalizumab.

BACKGROUND:To identify a reliable method of performing apnea testing as part of brain death determination in adult patients who develop loss of brainstem reflexes while receiving extracorporeal membrane oxygenation (ECMO). ECMO provides extracirculatory support to patients in cardiorespiratory failure who would otherwise be expected to die. Many studies have reported brain death as a potential complication of adult ECMO, but none have cited how apnea testing was performed in these patients. METHODS:This retrospective review identified adults 15 years or older treated with ECMO at our institution (2002-2010) and the method of determination of brain death when complete loss of brainstem reflexes occurred. RESULTS:Loss of all brainstem reflexes was identified in three cases (3/87, 3.4%). The apnea test was not performed since it was deemed "difficult," leading to withdrawal of ECMO and intensive care. Ancillary tests such as cerebral flow studies were not used because they may not document absent cerebral arterial flow due to the ischemic nature of the injury. We propose the use of an oxygenated apnea test on ECMO using continuous positive airway pressure (CPAP) through the ventilator or anesthesia bag, with an inline manometer and an end tidal CO(2) device. CONCLUSION/CONCLUSIONS:Apnea testing is essential in the determination of brain death, but may not be employed in ECMO-treated adult patients. Apnea testing using the above protocol may assist in better decision making for adult ECMO patients at risk of brain death.

OBJECTIVES/OBJECTIVE:To demonstrate a rare but potential mechanism of quadriplegia in a patient with fulminant pneumococcal meningitis complicated by severe intracranial hypertension. DESIGN/METHODS:Case report. SETTING/METHODS:Intensive care unit. PATIENT/METHODS:A 21-year-old man who presented with 3 days of headache, combativeness, and fever. INTERVENTION/METHODS:Antibiotics and steroids were initiated after lumbar puncture yielded purulent cerebrospinal fluid and streptococcus pneumoniae. RESULTS:The patient's course was complicated by severe cerebral edema necessitating intracranial pressure monitoring and intracranial pressure-targeted therapy. Within 5 days he developed quadriplegia and areflexia. Brain and cervical spine magnetic resonance imaging revealed patchy areas of T2 signal hyperintensity with associated gadolinium enhancement in the superior cervical spinal cord, cerebellar tonsils, and medulla. CONCLUSIONS:Quadriplegia secondary to tonsillar herniation in fulminant meningitis is rare but should be considered in patients with acute quadriparesis after treatment of increased intracranial pressure. Magnetic resonance imaging signal changes and gadolinium enhancement may be demonstrated. Significant improvement of cord symptoms can be expected.