Advances in Intraoperative Neurophysiology During Microvascular Decompression Surgery for Hemifacial Spasm

Microvascular decompression (MVD) is a widely used surgical intervention to relieve the abnormal compression of a facial nerve caused by an artery or vein that results in hemifacial spasm (HFS). Various intraoperative neurophysiologic monitoring (ION) and mapping methodologies have been used since the 1980s, including brainstem auditory evoked potentials, lateral-spread responses, Z-L responses, facial corticobulbar motor evoked potentials, and blink reflexes. These methods have been applied to detect neuronal damage, to optimize the successful decompression of a facial nerve, to predict clinical outcomes, and to identify changes in the excitability of a facial nerve and its nucleus during MVD. This has resulted in multiple studies continuously investigating the clinical application of ION during MVD in patients with HFS. In this study we aimed to review the specific advances in methodologies and clinical research related to ION techniques used in MVD surgery for HFS over the last decade. These advances have enabled clinicians to improve the efficacy and surgical outcomes of MVD, and they provide deeper insight into the pathophysiology of the disease.

Various MRI Findings of Toxocara canis Myelitis

PURPOSE@#To describe magnetic resonance imaging (MRI) findings in 10 cases of Toxocara canis myelitis and to analyze these findings to aid in the diagnosis of this condition.@*MATERIALS AND METHODS@#From June 2015 to March 2018, we retrospectively analyzed the electronic medical records and MR images of patients who were diagnosed with Toxocara canis myelitis. The analysis of the MR images was based on a discussion between an experienced spinal radiologist and a radiology resident.@*RESULTS@#This study classified MRI findings into the following two types. Type 1 was defined as central and diffuse T2 high signal intensity on the axial plane, which was observed in 50% of all cases. All lesions showed avid enhancement, mostly in the posterolateral or posterior region (4 cases, 80%). Type 2 was defined as wedge-shaped or focal T2 high signal intensity in the posterolateral or posterior region and corresponded to the remaining 50% of the cases. In this case, the extent of the lesion was relatively small and contrast enhancement was observed in only one case.@*CONCLUSION@#This study revealed that various imaging findings could be observed in cases of Toxocara canis myelitis, and the findings were classified into two types.

Incidentally Diagnosed Asymptomatic Pneumoparotid / 대한두경부종양학회지

Pneumoparotid is a rare cause of parotid gland swelling, and is caused by retrograde air reflux from the oral cavity, into the parotid gland via Stensen's duct. Most patients complained of painless swelling in the parotid region. Herein, we report a rare case of pneumoparotid, incidentally diagnosed without symptoms on CT, for follow-up of parotid lymph node enlargement.

Successful Treatment of Glycine-Receptor-Antibody-Mediated Progressive Encephalomyelitis with Rigidity and Myoclonus by Combining Steroids and Azathioprine

No abstract available.

Efficacy of Gaze Photographs in Diagnosing Ocular Myasthenia Gravis

BACKGROUND AND PURPOSE: The various tests that are routinely used to diagnose generalized myasthenia gravis, such as the edrophonium test, serum anti-acetylcholine-receptor antibodies (AChR-Ab), and repetitive nerve stimulation (RNS) tests, have lower diagnostic sensitivity in ocular myasthenia gravis (OMG). Diagnosing OMG becomes even more difficult when the clinical symptoms are subtle. There is no gold-standard diagnostic test available for OMG patients, and so this study compared the diagnostic sensitivity of gaze photographs with conventional tests in OMG. METHODS: Records of gaze photographs were available for 25 of 31 consecutive patients diagnosed with OMG. Each patient underwent a neuro-ophthalmologic examination, serum AChR-Ab, RNS, edrophonium test, ice tests, and the acquisition of gaze photographs. The margin reflex distance 1 (MRD1) was measured on each of the gaze photographs, with MRD1 < 2 mm or an interlid MRD1 difference of ≥2 mm on any of the gaze photographs defined as a positive sign of OMG. The diagnostic sensitivities of the tests were assessed. RESULTS: The mean age at onset was 38.5 years (range, 2–76 years), and 13 patients (52%) were men. The diagnostic sensitivities of the RNS test, AChR-Ab test, gaze photographs, and ice test were 56%, 64%, 80%, and 73%, respectively. CONCLUSIONS: The diagnostic sensitivity was higher for gaze photographs than for the other tests applied to OMG patients.

Clevudine Induced Mitochondrial Myopathy

Clevudine was approved as an antiviral agent for hepatitis B virus, which showed marked, rapid inhibition of virus replication without significant toxicity. However, several studies have reported myopathy associated with clevudine therapy. Also, we experienced seven patients who suffered from myopathy during clevudine therapy. To characterize clevudine-induced myopathy, we collected previously reported cases of clevudine myopathy and analyzed all the cases including our cases. We searched electronic databases that were published in English or Korean using PubMed and KoreaMed. Ninety-five cases with clevudine myopathy, including our seven cases, were selected and analyzed for the demographic data, clinical features, and pathologic findings. The 95 patients with clevudine-induced myopathy comprised 52 women and 43 men aged 48.9 years (27–76 years). The patients received clevudine therapy for about 14.2 months (5–24 months) before the development of symptoms. Weakness mainly involved proximal extremities, especially in the lower extremities, and bulbar and neck weakness were observed in some cases (13.7%). Creatine kinase was elevated in the majority of patients (97.9%). Myopathic patterns on electromyography were observed in most patients examined (98.1%). Muscle biopsy presented patterns compatible with mitochondrial myopathy in the majority (90.2%). The weakness usually improved within about 3 months after the discontinuation of clevudine. Though clevudine has been known to be safe in a 6-month clinical trial, longer clevudine therapy for about 14 months may cause reversible mitochondrial myopathy. Careful clinical attention should be paid to patients with long-term clevudine therapy.

Intraoperative Motor-Evoked Potential Disappearance versus Amplitude-Decrement Alarm Criteria During Cervical Spinal Surgery: A Long-Term Prognosis

BACKGROUND AND PURPOSE: We studied the clinical significance of amplitude-reduction and disappearance alarm criteria for transcranial electric muscle motor-evoked potentials (MEPs) during cervical spinal surgery according to different lesion locations [intramedullary (IM) vs. nonintramedullary (NIM)] by evaluating the long-term postoperative motor status. METHODS: In total, 723 patients were retrospectively dichotomized into the IM and NIM groups. Each limb was analyzed respectively. One hundred and sixteen limbs from 30 patients with IM tumors and 2,761 limbs from 693 patients without IM tumors were enrolled. Postoperative motor deficits were assessed up to 6 months after surgery. RESULTS: At the end of surgery, 61 limbs (2.2%) in the NIM group and 14 limbs (12.1%) in the IM group showed MEP amplitudes that had decreased to below 50% of baseline, with 13 of the NIM limbs (21.3%) and 2 of the IM limbs (14.3%) showing MEP disappearance. Thirteen NIM limbs (0.5%) and 5 IM limbs (4.3%) showed postoperative motor deficits. The criterion for disappearance showed a lower sensitivity for the immediate motor deficit than did the criterion for amplitude decrement in both the IM and NIM groups. However, the disappearance criterion showed the same sensitivity as the 70%-decrement criterion in IM (100%) and NIM (83%) surgeries for the motor deficit at 6 months after surgery. Moreover, it has the highest specificity for the motor deficits among diverse alarm criteria, from 24 hours to 6 months after surgery, in both the IM and NIM groups. CONCLUSIONS: The MEP disappearance alarm criterion had a high specificity in predicting the long-term prognosis after cervical spinal surgery. However, because it can have a low sensitivity in predicting an immediate postoperative deficit, combining different MEP alarm criteria according to the aim of specific instances of cervical spinal surgery is likely to be useful in practical intraoperative monitoring.

Proximal Median Neuropathy Caused by Axillary Brachial Plexus Block

An axillary brachial plexus block (BPB) is commonly used in local anesthesia, especially for hand surgery. Infraclavicular brachial plexopathy is a potential complication of axillary BPB. A 44-year-old man with an injury to his left third fingertip presented with weakness of the left thumb and index finger flexion after orthopedic surgery under axillary BPB. This was a rare case of proximal median neuropathy caused by axillary BPB. The diagnosis was confirmed by a detailed neurological examination and electrodiagnostic studies.

Pattern of Respiratory Deterioration in Sporadic Amyotrophic Lateral Sclerosis According to Onset Lesion by Using Respiratory Function Tests

Most amyotrophic lateral sclerosis (ALS) patients show focal onset of upper and lower motor neuron signs and spread of symptoms to other regions or the other side clinically. Progression patterns of sporadic ALS are unclear. The aim of this study was to evaluate the pattern of respiratory deterioration in sporadic ALS according to the onset site by using respiratory function tests. Study participants included 63 (42 cervical-onset [C-ALS] and 21 lumbosacral-onset [L-ALS]) ALS patients and 31 healthy controls. We compared respiratory function test parameters among the 3 groups. Age was 57.4+/-9.6 (mean+/-SD), 60.8+/-9, and 60.5+/-7 years, and there were 28, 15, and 20 male participants, in the C-ALS, L-ALS, and control groups, respectively. Disease duration did not differ between C-ALS and L-ALS patients. Sniff nasal inspiratory pressure (SNIP) was significantly low in C-ALS patients compared with controls. Maximal expiratory pressure (MEP) and forced vital capacity percent predicted (FVC% predicted) were significantly low in C-ALS and L-ALS patients compared with controls. Maximal inspiratory pressure to maximal expiratory pressure (MIP:MEP) ratio did not differ among the 3 groups. Eighteen C-ALS and 5 L-ALS patients were followed up. DeltaMIP, DeltaMEP, DeltaSNIP, DeltaPEF, and DeltaFVC% predicted were higher in C-ALS than L-ALS patients without statistical significance. Fourteen C-ALS (77.8%) and 3 L-ALS (60%) patients showed a constant MIP:MEP ratio above or below 1 from the first to the last evaluation. Our results suggest that vulnerability of motor neurons in sporadic ALS might follow a topographic gradient.

Balo's Concentric Sclerosis Mimicking Cerebral Tuberculoma

Balo's concentric sclerosis (BCS) is considered a rare variant of multiple sclerosis, which often mimics an intracranial neoplasm or abscess. We report the case of a 21-year-old woman presenting with BCS while undergoing treatment for pulmonary tuberculosis. Initial brain magnetic resonance imaging (MRI) findings were similar to those for cerebral tuberculoma, multiple metastases, or abscesses. However, the pathognomonic concentric sclerosis characteristic of BCS was seen on MRI. The antemortem confirmatory diagnosis of BCS was made by follow-up MRI and a brain biopsy. It is suggested that BCS should be included in the differential diagnosis of cerebral tuberculoma, especially in developing countries with a high prevalence of tuberculosis.

Hypolipidemia in Patients with Amyotrophic Lateral Sclerosis: A Possible Gender Difference?

BACKGROUND AND PURPOSE: We compared the levels of serum lipid, protein, and glucose between patients with amyotrophic lateral sclerosis (ALS) and healthy controls. METHODS: The serum levels of lipids [including triglycerides, cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL)], protein, and glucose of 95 patients with ALS (60 men) were compared with those of 99 age- and sex-matched healthy controls (64 men). Both groups had normal dietary intakes. RESULTS: Total cholesterol (p=0.004), LDL (p=0.040), triglyceride (p=0.025), and protein (p=0.010) levels, and LDL/HDL ratios (p<0.001) in men with ALS were significantly lower than those in their control counterparts. There were no such significant differences in these parameters between female patients with ALS and female controls. CONCLUSIONS: The serum levels of lipid and protein were significantly lower in male patients with ALS than in the male controls. Since we controlled for the confounding effects of dietary intake, hypolipidemia in ALS might be associated with the pathophysiology of the disease rather than being the result of the decreased dietary intake in ALS patients. Metabolic demand might increase in ALS, and it may be affected by gender.

A Case of GNE Myopathy Presenting a Rapid Deterioration during Pregnancy

BACKGROUND: GNE myopathy is characterized by early-adult-onset distal myopathy sparing quadriceps caused by mutations in the GNE gene encoding UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase, an enzyme in the sialic-acid synthesis pathway. CASE REPORT: A 27-year-old Korean woman presented a rapid deterioration in strength of the distal lower limbs during her first pregnancy. She was diagnosed with GNE myopathy and carrying the compound heterozygous mutations of the GNE gene (D208N/M29T). CONCLUSIONS: This is a representative case implying that an increased requirement of sialic acid during pregnancy might trigger a clinical worsening of GNE myopathy.

Assessment of Severity by High Resolution Ultrasonography in Carpal Tunnel Syndrome

BACKGROUND: Although nerve conduction study (NCS) is the method most frequently used to confirm clinical diagnosis of carpal tunnel syndrome (CTS), ultrasonographic (US) measurement can give additional information to confirm the diagnosis and also exclude other conditions of nearby soft tissues. However, whether or not the degree of swelling of median nerve (MN) reflects clinical severity has not been proven before. This study is aimed to investigate the further clinical usefulness of US in assessing CTS severity. METHODS: One hundred and twenty-four patients (248 hands) with electrophysiologically confirmed CTS were evaluated. Clinical severity was examined by Historic and Objective (Hi-Ob) scale. Padua scale was used for the severity of electrophysiological impairment. For US study, cross-sectional area (CSA) of the median nerve was measured at the proximal inlet of the carpal tunnel and graded. RESULTS: Ninety-four patients were female (75%) and median disease duration was 19 weeks. There was a good correlation between electrophysiological impairment and CSA of median nerve (correlation coefficient=0.442, p<0.001), and CSA was graded as US severity scale by electrophysiological severity of patients. A statistically significant correlation was found among US severity scale of the MN at wrist, clinical severity scale (correlation coefficient=0.397, p<0.001), and electrophysiological severity scale (correlation coefficient=0.371, p<0.001). CONCLUSIONS: This observation suggests MN swelling in CTS may reflect in itself the degree of nerve damage as expressed by the clinical picture. US measurement could also give additional information about severity of MN involvement above the diagnosis of CTS.

Ischemic Neuropathy Associated with Livedoid Vasculitis

BACKGROUND: Livedoid vasculitis is a chronic dermatological problem with an unclear etiology. Clinical findings are petechiae with painful ulcers in both lower extremities, which heal to become hyperpigmented and porcelain-white satellite lesions. There are only a few reported cases of livedoid vasculitis presenting in combination with peripheral neuropathy. CASE REPORT: We report the first case of a Korean patient presenting with mononeuritis multiplex combined with livedoid vasculitis, which was confirmed by electrophysiological and pathological studies. CONCLUSIONS: Our report supports the possible vaso-occlusive etiology of livedoid vasculitis in multifocal ischemic neuropathy.

Gene Therapy for Muscular Dystrophies: Progress and Challenges

Muscular dystrophies are groups of inherited progressive diseases of the muscle caused by mutations of diverse genes related to normal muscle function. Although there is no current effective treatment for these devastating diseases, various molecular strategies have been developed to restore the expressions of the associated defective proteins. In preclinical animal models, both viral and nonviral vectors have been shown to deliver recombinant versions of defective genes. Antisense oligonucleotides have been shown to modify the splicing mechanism of mesenger ribonucleic acid to produce an internally deleted but partially functional dystrophin in an experimental model of Duchenne muscular dystrophy. In addition, chemicals can induce readthrough of the premature stop codon in nonsense mutations of the dystrophin gene. On the basis of these preclinical data, several experimental clinical trials are underway that aim to demonstrate efficacy in treating these de-vastating diseases.

Motor Unit Number Estimation in Evaluating Disease Progression in Patients with Amyotrophic Lateral Sclerosis

We investigated the availability of motor unit number estimation (MUNE) as a quantitative method to assess the severity and clinical progression of amyotrophic lateral sclerosis (ALS). The 143 ALS patients were evaluated by statistical MUNE and the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). By using mean values of MUNE according to disease duration, regression equation between mean MUNE and disease duration was presented as a formula. The individual MUNE ratio was calculated by dividing individual MUNE value by mean MUNE value. All patients were classified into 2 groups (MUNE ratio or =1) according to the MUNE ratio. Comparison between the 2 groups revealed that the patients in MUNE ratio or =1 group were respectively assigned to rapid progression or slow progression. We recommended informative mean values of MUNE and best regression equation in ALS patients according to disease duration. These values allow us to evaluate the severity and rapidity of progression in ALS.

Clinical Features, Disability and Socioeconomic Status of Patients With Muscular Dystrophy in Korea

BACKGROUND: Since 2001, the Ministry of Health and Welfare in Korea has designated muscular dystrophy (MD) to be a rare and intractable disease, and has ensured that patients with this condition obtain support from the National Health Insurance Corporation for their medical expenditure. However, the health-related and socioeconomic status of Korean patients with MD has yet to be established. METHODS: We selected 441 patients with MD who received medical services at 17 neuromuscular centers during 2005. The medical records of selected patients were analyzed, and the subtype of MD was classified by its clinical course and diagnostic tests. A total of 95 patients or their family members participated in this health-related and socioeconomic status survey. RESULTS: Medical record analysis showed similar clinical and diagnostic characteristic data to those published previously in other countries: male predominance, being young at onset, and muscular weakness of the extremities as a predominant symptom in most patients. The diagnostic tests for MD were based on laboratory and electrophysiological studies. The most frequent form of MD among our cohort was Duchenne/Becker muscular dystrophy (42%). Our survey revealed the effect of the patients' profound disability on their activities of daily living. One-half of the patients were dissatisfied with the medical expenditure support service that was made available to them, and most patients suffered from a financial burden. The most important medical services to be developed in the future are expansion of the public health service or development of a rehabilitation hospital. CONCLUSIONS: This is the first multicenter-based epidemiologic study on the health-related and socioeconomic status of patients with MD in Korea. The findings indicate that medical coverage and public health service are currently inadequate and hence should be expanded in the future.

Alcohol-Related Neurologic Disorders: Ten Years of Experiences

Alcohol-related disorders are among the most costly health problems worldwide. Ingested alcohol is mainly metabolized by an oxidative pathway in the liver. Alcohol and its metabolic products (e.g., acetaldehyde and reactive oxygen species) have toxic effects on multiple organs, especially the nervous system. The diverse mechanisms of alcohol-related neurologic disorders include the direct toxic effects of alcohol, the alcohol withdrawal effect, nutritional deficiency secondary to alcoholism, and abnormalities of serum electrolytes and osmolality. We analyzed 156 cases of alcoholrelated neurologic disorders among admitted patients that had been referred in Korea during the previous 10 years. The duration of alcohol consumption ranged from 0.5 to 47 years (mean=17.8 years) and the mean amount of alcohol intake per day was 245.5 g. The 156 patients had the following diseases: Wernicke's encephalopathy (n=81, 51.9%), peripheral neuropathy (n=68, 43.6%), delirium tremens (n=59, 37.8%), Rum fit (n=31, 19.9%), pellagra encephalopathy (n=29, 18.6%), Korsakoff's psychosis (n=22, 14.2%), cerebellar atrophy (n=11, 7.0%), and alcoholic myopathy (n=6, 3.8%). We report on these cases and review the literature on alcohol-related neurologic disorders.

Plantar Nerve Conduction Studies in Diabetic Sensory Polyneuropathies With Normal Routine Conduction Studies

BACKGROUND: The results of a routine nerve conduction study (NCS) are sometimes normal in diabetic patients with clinical manifestations of sensory polyneuropathy, especially in the early stage. We report on the value of a plantar NCS in diabetic sensory polyneuropathy with normal results from a routine NCS. METHODS: Mixed nerve conduction data in the medial and lateral plantar nerves of both feet were obtained orthodromically in 47 normal subjects and 30 patients with diabetic sensory polyneuropathies with normal results from a routine NCS. The latency and amplitude of compound nerve action potentials (CNAPs) of plantar nerves were normal in the normal subjects. The results of a plantar NCS in the patient group were compared with these normal values. RESULTS: Nerve conduction abnormalities were found in 14 patients (46.7%). The rates of abnormal findings were 33.3% (20 of 60 nerves) and 31.7% (19 of 60 nerves) in the medial and lateral plantar nerves, respectively. A definite polyneuropathy pattern was found in 10 patients (33.3%). The CNAP amplitude was low or absent in 12 patients (85.7%) with abnormal nerve conduction, and 8 patients (57.1%) showed a prolonged CNAP latency. CONCLUSIONS: A plantar NCS is useful for detecting nerve conduction abnormalities in diabetic sensory polyneuropathy when normal results are obtained from a routine NCS. The diagnostic sensitivity of a routine NCS can be significantly increased by adding a plantar NCS when evaluating patients with sensory polyneuropathies, especially in the early stage.

Clinical and Genetic Analysis of Korean Patients with Facioscapulohumeral Muscular Dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominantly inherited muscular disorder, which is characterized by weakness of facial, shoulder and hip girdle, humeral, and anterior distal leg muscles. The FSHD gene has been mapped to 4q35 and a deletion of integral copies of a 3.3-kb DNA repeat motif named D4Z4 was known to be the genetic background of the disorder. Although FSHD is the second most common muscular dystrophy in adulthood, there were few reports on the genetically confirmed patients in Korea. Recently, we experienced four Korean patients with clinical features resembling FSHD. In order to confirm the diagnosis, conventional Southern blot (SB) analysis by using double digestion with EcoRI and BlnI and hybridization with p13E-11 probe was performed in three patients and newly developed long polymerase chain reaction (PCR) method was used for one patient because genomic DNA was not enough for conventional SB for this patient. All patients were demonstrated to have shortened D4Z4 repeats that were consistent with FSHD. Therefore, we could confirm the diagnosis of FSHD in four Korean patients and appropriate genetic counseling was done for the patients and their families. It is of note that long-PCR method could be a good alternative for conventional SB when D4Z4 repeats were less than 5.