Takehiro Uda

Comparison of neuropsychological outcomes after selective amygdalohippocampectomy versus anterior temporal lobectomy

Transsylvian selective amygdalohippocampectomy (TSA) is an operative technique designed to spare unaffected brain tissue during surgical treatment for mesial temporal lobe epilepsy. In contrast to standard anterior temporal lobectomy (ATL), the advantages of TSA with respect to postoperative cognitive outcome are equivocal. We compared cognitive function before and after surgery in 49 patients with unilateral mesial temporal lobe seizures who underwent either ATL (n=17) or TSA (n=32). All patients received neuropsychological testing before and 1 year after surgery. The intelligence quotient (IQ) increased postoperatively in both surgical groups. Memory evaluation in the ATL group revealed a postoperative decline in nonverbal memory after right-sided resection and a postoperative decline in verbal memory after left-sided resection. In the TSA group, there was a slight postoperative decline only in verbal memory after left-sided resection, but other memory function was well preserved. In particular, there was significant postoperative improvement in verbal memory after right-sided resection. Overall, memory function was better preserved in the TSA group than in the ATL group.

Assessment of cervical spondylotic myelopathy using diffusion tensor magnetic resonance imaging parameter at 3.0 tesla.

Study Design. Cross-sectional study. Objective. To assess spinal cord condition in patients with cervical spondylosis (CS), using diffusion tensor imaging parameter. Summary of Background Data. Although myelopathy is a common symptom after CS, clinically objective assessment for determination of surgical intervention is not straightforward. Methods. Twenty-six patients with CS and 30 normal control subjects were enrolled. Diffusion tensor imaging was obtained using a single-shot fast spin-echo–based sequence at 3.0 T. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in the axial plane at 6 spinal levels. To evaluate MD and FA in patients with CS considering the normal variation at each spinal level and between spinal levels, MD and FA at the most compressed spinal level were transformed to normalized values with a z score. Presence of myelopathy was predicted with the MD and FA z scores. Diagnostic validity of MD and FA was compared with receiver operating characteristic analysis. More effective parameter and the optimal cutoff value for prediction were determined. Results. In normal subjects, MD and FA were significantly different between spinal levels. In patients with myelopathy, an MD increase or an FA decrease was demonstrated in most cases. Although both an MD increase and an FA decrease had diagnostic validity for myelopathy, receiver operating characteristic analysis demonstrated a higher sensitivity and specificity for prediction of an MD increase than an FA decrease (areas under the curve for MD and FA were 0.903 and 0.760, respectively). An MD z score of 1.40 was considered to be the best diagnostic cutoff value with 100% sensitivity and 75% specificity. Conclusion. Myelopathy can be predicted with high accuracy with diffusion tensor imaging parameter, with the MD z score at the most compressed spinal level. Level of Evidence: 3

Memory outcome following transsylvian selective amygdalohippocampectomy in 62 patients with hippocampal sclerosis

OBJECT It remains unclear whether selective amygdalohippocampectomy, an operative technique developed for use in epilepsy surgery to spare unaffected brain tissue and thus minimize the cognitive consequences of temporal lobe surgery, actually leads to a better memory outcome. The present study was performed to determine the effects of selective surgery on memory outcome in patients with intractable mesial temporal lobe epilepsy due to hippocampal sclerosis treated using transsylvian selective amygdalohippocampectomy (TSA). METHODS The study population consisted of 62 patients with left hemisphere language dominance who underwent left-(31 patients) or right-sided (31 patients) TSA. All patients underwent comprehensive neuropsychological testing before and 1 month and 1 year after unilateral TSA. Verbal Memory I, Nonverbal Memory I, Total Memory, Attention, and Delayed Recall were assessed using the Wechsler Memory Scale-Revised, whereas Verbal Memory II was assessed using the Miyake Verbal Retention Test (MVRT), and Nonverbal Memory II was assessed using the Benton Visual Retention Test. Separate repeated-measures multivariate analysis of variance (MANOVA) were performed for these intervals with memory scores. RESULTS The results of MANOVA indicated that patients who underwent right-sided TSA showed significant improvements in Verbal Memory I (preoperatively vs 1 month postoperatively, p < 0.0001; and preoperatively vs 1 year postoperatively, p = 0.0002), Nonverbal Memory I (preoperatively vs 1 month postoperatively, p = 0.0003; and preoperatively vs 1 year postoperatively, p = 0.006), and Delayed Recall (preoperatively vs 1 month postoperatively, p = 0.028) at both 1-month and 1-year follow-ups. In addition, Verbal Memory II (MVRT) was also significantly improved 1 year after surgery (p = 0.001). In the group of patients who underwent left-sided TSA, both Verbal Memory I and II were maintained at the same level 1 month after surgery, whereas the Verbal Memory I score 1 year after surgery increased with marginal significance (p = 0.074). In addition, Verbal Memory II showed significant improvement 1 year after surgery (p = 0.049). There were no significant changes in Nonverbal Memory I and II, Attention, or Delayed Recall at either the 1-month or 1-year follow-up. CONCLUSIONS Results of the present study indicated that left-sided TSA for hippocampal sclerosis tends to improve verbal memory function with the preservation of other types of memory function. Moreover, right-sided TSA for hippocampal sclerosis can lead to significant improvement in memory function, with memory improvement observed 1 month after right-sided TSA and persisting 1 year after surgery.

Outcomes of contemporary use of rectangular titanium stand-alone cages in anterior cervical discectomy and fusion: Cage subsidence and cervical alignment

Cervical intervertebral disc replacement using a rectangular titanium stand-alone cage has become a standard procedure for anterior cervical discectomy and fusion (ACDF). We examined outcomes resulting from the contemporary use of rectangular titanium stand-alone cages for ACDF, particularly focusing on cage subsidence and subsequent kyphotic malalignment. Patient data were collected prospectively, and a total of 47 consecutive patients who underwent periodic follow-up of at least 1 years duration after ACDF were studied retrospectively. Sixty-three rectangular titanium cages were implanted during 31 1-level and 16 2-level procedures. None of the patients developed surgery-related complications (including cage displacement or extrusion). Mean Neurosurgical Cervical Spine Scale scores were significantly improved at 1 year after surgery. Twelve of the 63 inserted cages (19.0%) were found to have cage subsidence, occurring in 11 of 47 patients (23.4%). There was no significant difference in functional recovery between patients with and without cage subsidence. Logistic regression analysis indicated that fusion level, cage size and cage position were significantly related to cage subsidence. The distraction ratio among patients with cage subsidence was significantly higher than that among patients without cage subsidence. Cage subsidence resulted in early deterioration of local angle and total alignment of the cervical spine. Although a longer follow-up is warranted, a good surgical outcome with negligible complications appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF. Excessive distraction at the fusion level should be avoided, and cage position should be adjusted to the anterior vertical line.

Surgery for amygdala enlargement with mesial temporal lobe epilepsy: pathological findings and seizure outcome

Objective Amygdala enlargement (AE) has been suggested to be a subtype of mesial temporal lobe epilepsy (MTLE). However, most reports related to AE have referred to imaging studies, and there have been few reports regarding surgical and pathological findings. The present study was performed to clarify the surgical outcomes and pathology of AE. Methods Eighty patients with drug-resistant MTLE were treated surgically at the Tokyo Metropolitan Neurological Hospital between April 2010 and July 2013. Of these patients, 11 were diagnosed as AE based on presurgical MRI. Nine patients with AE underwent selective amygdalohippocampectomy, while the remaining two patients underwent selective amygdalotomy with hippocampal transection. Intraoperative EEG was routinely performed. The histopathology of the resected amygdala tissue was evaluated and compared with the amygdala tissue of patients with hippocampal sclerosis. Results Pathological findings indicated that 10 of 11 specimens had closely clustering hypertrophic neurons with vacuolisation of the background matrix. Slight gliosis was seen in nine specimens, while the remaining two showed no gliotic changes. Intraoperative EEG showed abnormal sharp waves that seemed to originate not from the amygdala but from the hippocampus in all cases. Ten patients became seizure-free during the postoperative follow-up period. Conclusions Histopathologically, clustering hypertrophic neurons and vacuolation with slight gliosis or without gliosis were considered to be pathological characteristics of AE. Amygdalohippocampectomy or hippocampal transection with amygdalotomy is effective for seizure control in patients with AE.

Transsylvian hippocampal transection for mesial temporal lobe epilepsy: surgical indications, procedure, and postoperative seizure and memory outcomes

OBJECT Amygdalohippocampectomy is a well-established, standard surgery for medically intractable mesial temporal lobe epilepsy (MTLE). However, in the case of MTLE without hippocampal atrophy or sclerosis, amygdalohippocampectomy is associated with decreased postoperative memory function. Hippocampal transection (HT) has been developed to overcome this problem. In HT the hippocampus is not removed; rather, the longitudinal hippocampal circuits of epileptic activities are disrupted by transection of the pyramidal layer of the hippocampus. The present study describes a less invasive modification of HT (transsylvian HT) and presents the seizure and memory outcomes for this procedure. METHODS Thirty-seven patients with MTLE (18 men and 19 women; age range 9-63 years; 19 with surgery on the right side and 18 with surgery on the left side; seizure onset from 3 to 34 years) who were treated with transsylvian HT were retrospectively analyzed. All patients had left-side language dominance, and follow-up periods ranged from 12 to 94 months (median 49 months). Seizure outcomes were evaluated for all patients by using the Engel classification. Memory function was evaluated for 22 patients based on 3 indices (verbal memory, nonverbal memory, and delayed recall), with those scores obtained using the Wechsler Memory Scale-Revised. Patients underwent evaluation of the memory function before and after surgery (6 months-1 year). RESULTS Engel Class I (completely seizure free) was achieved in 25 patients (67.6%). Class II and Class III designation was achieved in 10 (27%) and 2 patients (5.4%), respectively. There were differences in memory outcome between the sides of operation. On the right side, verbal memory significantly increased postoperatively (p = 0.003) but nonverbal memory and delayed recall showed no significant change after the operation (p = 0.718 and p = 0.210, respectively). On the left side, all 3 indices (verbal memory, nonverbal memory, and delayed recall) showed no significant change (p = 0.331, p = 0.458, and p = 0.366, respectively). CONCLUSIONS Favorable seizure outcome and preservation of verbal memory were achieved with transsylvian HT for the treatment of MTLE without hippocampal atrophy or sclerosis.

Quinidine therapy for West syndrome with KCNTI mutation: A case report

The KCNT1 gene encodes the sodium-dependent potassium channel, with quinidine being a partial antagonist of the KCNT1 channel. Gain-of-function KCNT1 mutations cause early onset epileptic encephalopathies including migrating partial seizures of infancy (MPSI). At 5months of age, our patient presented with epileptic spasms and hypsarrhythmia by electroencephalogram. Psychomotor retardation was observed from early infancy. The patient was diagnosed with West syndrome. Consequently, various anti-epileptic drugs, adrenocorticotropic hormone therapy (twice), and ketogenic diet therapy were tried. However, the epileptic spasms were intractable. Whole exome sequencing identified a KCNT1 mutation (c.1955G>T; p.G652V). At 2years and 6months, the patient had daily epileptic spasms despite valproate and lamotrigine treatment, and was therefore admitted for quinidine therapy. With quinidine therapy, decreased epileptic spasms and decreased epileptiform paroxysmal activity were observed by interictal EEG. Regarding development, babbling, responsiveness, oral feeding and muscle tone were ameliorated. Only transient diarrhea was observed as an adverse effect. Thus, quinidine therapy should be attempted in patients with West syndrome caused by KCNT1 mutations, as reported for MPSI.

An intradural skull base chordoma presenting with acute intratumoral hemorrhage

We present a rare case of skull base chordoma of extraosseous intradural type that presented as acute intratumoral hemorrhage. Surgical removal of the tumor was accomplished using a skull base approach.

Relapse of herpes simplex virus encephalitis after surgical treatment for temporal lobe epilepsy: rare complication of epilepsy surgery.

Herpes simplex virus (HSV) is the most common cause of fatal encephalitis. After the primary infection, the viral DNA establishes a lifelong latent infection in the cell nucleus and reactivation of HSV may occur at any time in the patient’s life. Here, we report an unusual case of a 20-year-old woman with a history of HSV encephalitis who suffered a relapse of encephalitis after surgical treatment for mesial temporal lobe epilepsy (MTLE). The patient was admitted with a complaint of epilepsy. She had a past history of HSV encephalitis at 1 year old, which was confirmed by polymerase chain reaction (PCR). Her seizure started at 10 years old and remained intractable despite medication. On admission, the patient showed no neurological deficits. Interictal electroencephalography (EEG) revealed paroxysmal spike-and-wave complexes at the left anterior and middle temporal electrodes. Video-EEG monitoring demonstrated ictal onset from the left anterior temporal electrode and the patient displayed a particular semiological appearance in MTLE. Magnetic resonance imaging (MRI) demonstrated a hyperintense mesial occipital lesion on T2-weighted imaging that was considered to represent ulegyria from the infantile HSV encephalitis (Fig. 1a). Fluid-attenuated inversion recovery (FLAIR) imaging showed no abnormality in the hippocampus or surrounding temporal structures (Fig. 1b). N-isopropyl-I-p-iodoamphetamine single-photon emission computed tomography revealed decreased cerebral blood flow in the left mesial temporal lobe. The patient was diagnosed with left MTLE and underwent amygdalohippocampectomy [4, 10–13]. Pathological diagnosis was mild hippocampal sclerosis without findings of chronic viral encephalitis. On postoperative day (POD) 11, she developed high fever with disturbance of consciousness and motor aphasia. Cerebrospinal fluid (CSF) testing showed 43 9 10/L white blood cells (WBCs) (differential: 42 lymphocytes, 1 polymorph), 41 mg/dl of protein, normal glucose levels, and negative results for bacterial cultures. MRI FLAIR demonstrated diffuse signal hyperintense lesions with edematous changes in bilateral frontal lobes and the left thalamus (Fig. 2). Treatment was immediately initiated using high-dose acyclovir (10 mg/kg, intravenously every 8 h). Repeat CSF testing on POD 13 demonstrated elevations of WBCs to 608 9 10/L (differential: 564 lymphocytes, 44 polymorphs), protein to 125 mg/dl, normal glucose levels. On POD 17, HSV was identified in the CSF by PCR and a diagnosis of HSV encephalitis was suspected. On POD 21, the pyrexia subsided and symptoms gradually improved over the next 2 weeks. The patient was discharged from hospital without assistance. To our knowledge, three previous reports have described relapse of HSV encephalitis after brain surgery [1–3]. In the present case, the following two situations may have enhanced the reactivation of HSV. First, ulegyria that may have been associated with the initial HSV encephalitis was located around the lateral ventricle, adjacent to the surgically resected region. Second, neurons of the entorhinal cortex, which was included in the resected region, have been reported as one of the sites of HSV latent infection [7]. This complication is difficult to diagnose initially, because the clinical presentation of encephalitis is usually nonspecific, with symptoms such as headache, pyrexia and T. Uda (&) H. Ito A. Hosono S. Sunaga M. Morino Department of Neurosurgery, Tokyo Metropolitan Neurological Hospital, 2-6-1, Musashidai, Fuchu, Tokyo 183-0042, Japan e-mail: uda_takehiro@hotmail.com

Prediction of the efficacy of surgical intervention in patients with cervical myelopathy by using diffusion tensor 3T-magnetic resonance imaging parameters.

Background: The clinical significance of diffusion tensor (DT) magnetic resonance imaging (MRI) parameters was analyzed to predict postoperative functional recovery in patients with cervical myelopathy. Materials and Methods: Sixteen patients with cervical myelopathy caused by cervical spondylosis, disk herniation or ossification of the posterior longitudinal ligament who underwent surgical intervention in our institute were enrolled in this retrospective study. There were 7 men and 9 women, with a mean age of 62.8 years. Clinical assessment was done before surgery and at least 3 months after surgery. All patients underwent whole-body 3.0-Tesla MRI before surgery. DT images (DTIs) were obtained using a single-shot fast spin-echo-based sequence. Mean values of mean diffusivity (MD) and fractional anisotropy (FA) at 6 disk levels of the cervical spine were measured using manual setting of regions of interest. The MD and FA values at the most compressed part were analyzed. Absolute MD and FA values at the most compressed spinal level in patients were transformed into the normalized values with a z-score analysis. Results: MD-z may decrease with the severity of cervical myelopathy. Receiver operating characteristic analysis of MD-z and FA-z suggested that both MD-z and FA-z have clinical validity for predicting the efficacy of surgical intervention, but MD-z was considered to be the most appropriate value to predict the efficacy of surgery. Conclusions: DTIs may be a promising modality to predict functional recovery after surgery. MD changes may reflect spinal cord condition and its reversibility.