Otogenic Intracranial Abscesses, Our Experience Over the Last Four Decades.

OBJECTIVE: To evaluate the predisposing factors for otogenic intracranial abscesses, assess their changes over time, and analyze how they differ from those due to other causes. MATERIALS AND METHODS: The medical records of all patients treated for otogenic intracranial abscesses, between 1970 and 2012 at a tertiary referral center, were retrospectively analyzed. The analysis included patient demographics, clinical characteristics, causative pathogens, treatments, outcomes, and comparisons of otogenic and non-otogenic intracranial abscesses. RESULTS: Of all intracranial abscesses, 11% (n=18) were otogenic. In the 1970s, otogenic infections were a common predisposing factor for intracranial abscess; but within our study period, the incidence of otogenic intracranial abscesses decreased. Most (94%) otogenic cases were due to chronic suppurative otitis media and 78% were associated with cholesteatoma. Most patients (94%) had ear symptoms. The most common presenting symptoms were discharge from the infected ear (50%), headache (39%), neurological symptoms (28%), and fever (17%). The most common pathogens belonged to Streptococcus spp. (33%), Gram-negative enteric bacteria (22%), and Bacteroides spp. (11%). Neurosurgery was performed on all patients, 69% of which were prior to a later ear surgery. Surgery of the affected ear was performed on 14 patients (78%). A favorable recovery was typical (78%); however, one patient died. CONCLUSION: Otogenic intracranial abscesses were most commonly due to a chronic ear infection with cholesteatoma. Ear symptoms and Gram-negative enteric bacteria were more common among patients with otogenic than non-otogenic intracranial abscesses.

Intracranial abscesses over the last four decades; changes in aetiology, diagnostics, treatment and outcome.

Background The development of modern medicine has resulted in changes in the predisposing conditions, clinical picture, treatment and results of treatment of intracranial abscesses. This study sought to evaluate these changes in a hospital district. Methods A retrospective analysis of the clinical data of all patients treated due to intracranial abscesses at a tertiary referral centre, between 1970-2012. Results The total number of intracranial abscesses was 166. The incidence of intracranial abscesses was 0.33/100 000/year (2000-2012). The most common predisposing conditions were infection of the ear-, nose- and throat region (22%), odontogenic infection (15%) and cardiac anomaly (13%). Lately (2000-2012), infections of the ear-, nose- and throat region (15%) and cardiac anomalies (5%) have become less common, whereas odontogenic infections (32%) have become more common. The most common pathogens belong to Streptococcus spp (42%), Fusobacteriae (14%), Actinomycetales (8%) and Staphylococcus spp (8%). Most patients (66%) experienced a favourable recovery; the proportion of patients with favourable outcome enabling return to prior occupation rose over time, from 12% in 1970-1989 to 24% in 1990-2012. Conclusions The predisposing conditions for intracranial abscesses have changed markedly within the study period. Odontogenic infections have become a common predisposing condition, whereas infections of the ear-, nose- and throat region and cardiac malformations are nowadays less common as predisposing conditions compared to at the beginning of the study period. The proportion of patients with favourable outcome enabling return to prior occupation seems to have increased with time.

Etiology and Long-Term Outcomes of Late-Onset Infantile Spasms.

OBJECTIVES: The purpose of the study was to evaluate the etiology and long-term outcomes of late-onset epileptic spasms (LOS). METHODS: This is a retrospective analysis of all consecutive patients seen at our center with onset of clusters of epileptic spasms between 1 and 3 years of age in 1995 through 2005. RESULTS: Overall, 17 children with LOS were identified. Overall, 14 children (82%) had structural etiology. Six patients received resective surgical treatment. Five had focal cortical dysplasia type 1 (FCD1) histology (29% of all the patients). Overall, 16 children were followed for 2 to 18 years. At the latest follow-up, seizure freedom was observed in 67% of the operated and in 50% of the nonoperated patients. Normal cognition or only mild mental deficiency was observed in nine patients (56%), of whom eight were seizure-free. All patients with intractable spasms had a severe mental deficiency. CONCLUSION: The overall cognitive outcome of LOS was more favorable than in the previous reports and was associated with seizure freedom. FCD1 is a frequent etiology for LOS and the cognitive outcome of patients with FCD1 seemed to be favorable.

[Vestibular schwannoma: active treatment or follow-up?]. / Vestibulaarischwannooma: aktiivinen hoito vai seuranta?

Vestibular schwannoma is a rare benign tumor of a cranial nerve. The symptom picture is usually a varying one, centering on otogenic symptoms, such as hearing loss, tinnitus and dizziness. The diagnosis is often made only after the patient has already had symptoms for a longer time. The number of tumors found yearly in Finland is estimated to be approximately 50 to 100. Even very small tumors are detected by contrast-enhanced magnetic resonance imaging. Since a significant proportion of the tumors remain unchanged in size over a follow-up observation period of several years, follow-up instead of surgical treatment is considered adequate for some of the patients.

[EEG under the surface]. / EEG pintaa syvemmältä.

Epilepsy work-up is based on history and scalp EEG. Drug resistant epilepsy should be evaluated in a dedicated epilepsy surgery unit. Sometimes non-invasive studies fail to localize the epileptogenic area in focal epilepsy and then the work up can be complemented with intracranial EEG. Intracranial electrodes are implanted either in the subdural space or intraparenchymally. This is followed by one to two weeks of EEG monitoring in a specialized videotelemetry unit. Intracranial EEG helps to define the borders of the epileptogenic area for resection. The ultimate objective is to render the patient seizure free. The outcome of resective epilepsy surgery depends on the etiology of epilepsy, localization of the epileptogenic area and MR image yield.

Functional plasticity of the motor cortical structures demonstrated by navigated TMS in two patients with epilepsy.

BACKGROUND: Recently, navigated transcranial magnetic stimulation (nTMS) has been suggested to be useful in preoperative functional localization of motor cortex in patients having tumors close to the somatomotor cortex. Resection of tumors in anatomically predicted eloquent areas without adverse effects have emphasized functional plasticity elicited by intracranial pathology. OBJECTIVE: To describe functional plasticity of motor cortex indicated by nTMS in two patients with epilepsy. METHODS: nTMS, functional MRI (fMRI), diffusion-tensor (DT)-tractography and magnetoencephalography (MEG) were utilized to preoperatively localize motor cortical areas in the workup for epilepsy surgery. The localizations were compared with each other, with the cortical anatomical landmarks, and in one patient with invasive electrical cortical stimulation (ECS). RESULTS: In two out of 19 studied patients, nTMS identified motor cortical sites that differed from those indicated by anatomical landmarks. In one patient, nTMS activated preferentially premotor cortex rather than pathways originating from the precentral gyrus. MEG and fMRI localizations conformed with nTMS whereas ECS localized finger motor function into the precentral gyrus. Resection of the area producing motor responses in biphasic nTMS did not produce a motor deficit. In the other patient, nTMS indicated abnormal ipsilateral hand motor cortex localization and confirmed the functionality of aberrant motor cortical representations of the left foot also indicated by fMRI and DT-tractography. CONCLUSION: nTMS may reveal the functional plasticity and shifts of motor cortical function. Epileptic foci may modify cortical inhibition and the nTMS results. Therefore, in some patients with epilepsy, the nTMS results need to be interpreted with caution with regard to surgical planning.

Sensitivity and specificity of seizure-onset zone estimation by ictal magnetoencephalography.

PURPOSE: Ictal video-electroencephalography (EEG) is commonly used to establish ictal onset-zone location. Recently software development has enabled systematic studies of ictal magnetoencephalography (MEG). In this article, we evaluate the ability of ictal MEG signals to localize the seizure-onset zone. METHODS: Twenty-six patients underwent ictal MEG and epilepsy surgery. Prediction of seizure-onset zone by ictal and interictal MEG was retrospectively compared with ictal-onset area found by intracranial EEG in 12 patients. The specificity and sensitivity of the prediction were calculated at hemisphere-lobe (HL) and at hemisphere-lobe-surface (HLS) levels. KEY FINDINGS: The sensitivity of ictal MEG source localization was 0.958 on HL and 0.706 on HLS levels, and its specificity was 0.900 on HL and 0.731 on HLS levels. The interictal MEG dipole cluster, defined as >10 dipoles on one lobar surface, had sensitivity of 0.400 and specificity of 0.769. Ictal MEG was equally sensitive and specific on dorsolateral and nondorsolateral neocortical surfaces up to a depth of 4 cm from the scalp. SIGNIFICANCE: Sources of ictal-onset MEG signals and interictal dipole clusters are essentially equally specific in estimation of the ictal-onset zone on lobar surface resolution, but ictal MEG is more sensitive. On the lobe resolution, ictal MEG estimates ictal-onset zone with high sensitivity and specificity.

Microsurgical treatment of temporal lobe cavernomas.

BACKGROUND: Cavernomas of the temporal lobe occur in 10-20% of patients with cerebral cavernomas. They frequently cause epileptic seizures, some of which tend to become refractory to medical therapy. Surgical removal of safely achievable symptomatic lesions has been frequently consistent with good long-term outcome. In the present study, a postoperative outcome is assessed. METHODS: Of our 360 consecutive patients with cerebral cavernomas, 53 (15%) had a single cavernoma in the temporal lobe. Forty-nine patients were treated surgically and were included in the study. All data were analyzed retrospectively. The cavernomas were allocated into three groups based on the temporal lobe site: medial, anterolateral, and posterolateral. To collect follow-up data, all available patients were interviewed by phone. Seizure outcome was assessed using the Engel classification and general outcome using the Glasgow Outcome Scale (GOS). RESULTS: Patients' median age at presentation was 37 (range, 7-64) years, with a female/male ratio of 2.5:1. Epileptic seizures occurred in 40 patients (82%). Median duration of seizures preoperatively was 3 (range, 0.1-23) years. In addition, four patients (10%) had memory disorder. Three patients without history of seizures (6%) complained of headache and two (4%) had memory problems. Three patients (6%) had an incidental cavernoma. Hemorrhage occurred in nine patients (18%) preoperatively. Median postoperative follow-up time was 6 (range, 0.2-26) years. Favorable seizure outcome (Engel class I and II) was registered in 35 patients (90%). Ten patients (25%) who had only a single seizure before surgery were seizure free during postoperative follow-up. Good general outcome (GOS, 4.5) was detected in 46 patients (96%). Two patients (4%) developed a new mild memory deficit after surgery, and in two patients existing memory deficits worsened. CONCLUSIONS: Microsurgical removal of temporal lobe cavernomas is a safe and effective method to improve seizure outcome in patients with medically intractable epilepsy and to prevent deterioration caused by hemorrhage.

The effect of surgery in encephalopathy with electrical status epilepticus during sleep.

PURPOSE: We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery. METHODS: All patients had symptomatic etiology of ESES and preoperative neuropsychological deterioration. Ten patients had daily atypical absences. Clinical outcome was assessed at 6 months and at 2 years after surgery. Clinical and EEG data were reviewed retrospectively. The spike propagation pattern and area and source strength in source montage were analyzed from preoperative and postoperative EEG studies. KEY FINDINGS: Preoperative sleep EEG showed electrical status epilepticus during sleep (SES) with one-way interhemispheric propagation in nine patients and with two-way interhemispheric propagation in four. The age of the patients at the time of surgery ranged from 3.6-9.9 years. Focal resection (two patients) or hemispherotomy (one patient with postoperative EEG) either terminated SES or restricted the discharge to one region. Either reduced SES propagation area or source strength was found in four of eight callosotomy patients with postoperative EEG. Of patients who had seizures preoperatively, Engel class I-II seizure outcome was observed in two of three children after focal resection or hemispherotomy and in two of eight children after callosotomy. None of these patients with Engel class I-II outcome had SES with two-way interhemispheric propagation on preoperative EEG. Cognitive deterioration was halted postoperatively in all except one patient. Cognitive catch-up of more than 10 IQ points was seen in three patients, all of whom had shown a first measured IQ of >75. SIGNIFICANCE: Patients with pharmacoresistant ESES based on symptomatic etiology may benefit from resective surgery or corpus callosotomy regarding both seizure outcome and cognitive prognosis.

Two-year follow-up of intelligence after pediatric epilepsy surgery.

Research findings concerning cognitive effects of pediatric epilepsy surgery form an important basis for decisions about surgery. However, most follow-up studies have been of limited duration. In this study, a 2-year follow-up of intelligence was undertaken. Risk factors were analyzed. Included were 38 patients aged 3 to 17 years. Surgery was left in 19 patients and right in 19 patients. Types of surgery included temporal lobe resection (n = 23), extratemporal or multilobar resection (n = 8), and hemispherectomy (n = 7). The Wechsler Scales of Intelligence were administered presurgically, 6 months postsurgically, and 2 years postsurgically. No significant change in verbal or performance intelligence quotient (IQ) was demonstrated on a group level. Lateralization, type of surgery, age at surgery, sex, and presurgical IQ did not affect outcome. Across assessments, IQ scores of left-hemisphere patients were lower than those of right-hemisphere patients. Scores of patients in the hemispherectomy group were lower than those of the extratemporal or multilobar resection group, which were lower than the temporal lobe resection group. Scores improved significantly in six patients and deteriorated in seven. In conclusion, epilepsy surgery in children and adolescents does not, in general, have a significant impact on cognitive development in a 2-year perspective. In individual patients, poor seizure control and extensive surgery for Rasmussen's encephalitis were related to a deterioration of IQ.

Metabolite phantom correction of the nonuniform volume-selection profiles in MR spectroscopic imaging: application to temporal lobe epilepsy.

BACKGROUND AND PURPOSE: In MR spectroscopic imaging (MRSI), the volume-selection profiles of metabolites differ from each other. These differences cause variations in metabolite intensities, which are particularly prominent when the hippocampi are evaluated. We hypothesize that the errors arising from these effects cause notable artifact when temporal lobe epilepsy (TLE) is lateralized with MRSI. METHODS: We examined a metabolite phantom, control subjects, and patients with TLE by using MRSI. We calculated the error arising from the different volume-selection profiles of metabolites in vitro and evaluated this correction in the examination of the control subjects and in the lateralization of epilepsy in the patients. RESULTS: Without a correction, a considerable error in the metabolite content existed, even deep inside the spectroscopic volume of interest. The result was false asymmetry (P < .008) in the hippocampi of control subjects. Among the 11 patients, TLE was correctly lateralized in three only after the correction was made, and in one, TLE was incorrectly lateralized. CONCLUSION: The volume-selection profiles of N-acetylaspartate, choline, and creatine differ enough to cause a significant error, even in the metabolite ratios, when patients with TLE are examined with MRSI. We propose a simple phantom method to correct for this error without a need to modify the pulse sequence.

Low-grade gliomas and focal cortical developmental malformations: differentiation with proton MR spectroscopy.

PURPOSE: To assess proton magnetic resonance (MR) spectroscopy in differentiating between low-grade gliomas and focal cortical developmental malformations (FCDMs). MATERIALS AND METHODS: Eighteen patients with seizures and a cortical brain lesion on MR images were studied with proton MR spectroscopy. A metabolite ratio analysis was performed, and the metabolite signals in the lesion core were compared with those in the contralateral centrum semiovale and in the corresponding brain sites in 18 control subjects to separately obtain the changes in N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine-phosphocreatine (Cr). Ten patients had a low-grade glioma (three, oligodendrogliomas; three, oligoastrocytomas; three, astrocytomas; and one, pilocytic astrocytoma), and eight had FCDM (five, focal cortical dysplasias and three, dysembryoplastic neuroepithelial tumors). Linear discriminant analysis and Student t test were used for statistical comparisons. RESULTS: Loss of NAA and increase of Cho were more pronounced in low-grade gliomas than in FCDMs (NAA, -72% +/- 15 [+/- SD] vs -29% +/- 22, P <.001; Cho, 117% +/- 56 vs 21% +/- 66, P <.01). Changes in NAA and Cho helped differentiate low-grade gliomas from FCDMs, and changes in Cho and Cr helped differentiate astrocytomas from oligodendrogliomas and oligoastrocytomas. Metabolite NAA/Cho and NAA/Cr ratios helped differentiate low-grade gliomas from FCDMs but did not differentiate glioma subtypes. CONCLUSION: MR spectroscopy allows distinction between low-grade gliomas and FCDMs and between low-grade glioma subtypes. Metabolite changes are more informative than are metabolite ratios.

Postural stability after vestibular schwannoma surgery.

Factors related to postural stability and the course of recovery after vestibular schwannoma surgery were analyzed in a retrospective study of 177 patients and in a prospective study of 44 patients. Before surgery, 7 of the 44 patients in the prospective group complained of postural instability. The body sway velocity was measured. In the retrospective study, the sway velocity was abnormal under nonvisual control in 63% of the patients and under visual control in 34%. The sway velocity correlated with tumor size, smooth pursuit deficit, and postoperative work history. We compared patients with abnormal postural control to those with normal postural control, and found that the former relied to a greater extent on visual information and the latter on proprioceptive information. In the prospective study, the sway velocity increased after the operation, and 1 year after surgery it had not returned to preoperative values. In the logistic regression analysis, a translabyrinthine approach, rehabilitation, the patient's age, and preserved function of the facial nerve predicted a good outcome of postural stability. The retrosigmoid approach and depression were the most significant risk factors for postoperative gait difficulties. Vestibular rehabilitation increased the reliance on proprioception for maintenance of postural control and improved postural stability.

Is hearing preservation useful in vestibular schwannoma surgery?

The goal of our study was to examine the usefulness of preserved hearing after unilateral vestibular schwannoma removal. The patients were assessed by clinical evaluation, preoperative and postoperative audiometric evaluation, operative findings, and postoperative functional results. Hearing was preserved in 47 of 119 patients. The postoperative hearing was better than 30 dB in 10 patients. During the follow-up, the hearing decreased 5 dB on average, and almost all of the decrement occurred during the first 6 months. Subjectively, the preserved hearing assisted in understanding of speech in 62% of the patients. Tinnitus did not interfere with understanding of speech. The age of the patients was the most significant factor associated with preserved hearing. Sixty-six percent of the patients with hearing preservation rated their preserved hearing as valuable. Neither tinnitus nor speech distortion reduced the appreciation for hearing preservation. We conclude that efforts to preserve hearing are worthwhile.