Retrograde Epidural Spinal Cord Stimulation for the Treatment of Intractable Neuropathic Pain Following Spinal Cord and Cauda Equina Injuries: A Case Report and Literature Review.

Spinal cord stimulation (SCS) offers an alternative treatment for refractory pain resulting from various etiologies. Generally, SCS electrodes are inserted in an anterograde fashion, moving from caudal to rostral direction. However, there are instances where anterograde placement is unfeasible due to technical limitations. We present the use of retrograde surgical electrode placement in SCS for a patient with extensive epidural fibrosis at the site intended for electrode insertion. A 48-year-old female suffering from refractory neuropathic pain caused from injuries to the conus medullaris and cauda equina opted for SCS. During the SCS trial procedure, challenges emerged when attempting percutaneous electrode insertion at the site of a prior T12 laminectomy. However, the trial stimulation resulted in significant pain relief. For the permanent placement of the stimulator, utilizing a surgical electrode centered at T11 vertebral level, a considerable amount of epidural fibrosis was encountered at the entry of the spine, particularly at the T12 vertebral level. To avoid dural injury and ensure accurate electrode positioning, a retrograde technique for surgical electrode was employed via partial laminectomies at the T9-T10 level. The final electrode positioning was in accordance with the preoperative plan, well-centered at the T11 vertebral level. The patient experienced sustained relief from neuropathic pain over the long term. Retrograde epidural SCS is a suitable option for cases characterized by extensive epidural fibrosis resulting from a previous spinal surgery or when the anterograde placement of the electrode is unattainable due to aberrant vertebral anatomy.

Exploiting nanopore sequencing for characterization and grading of IDH-mutant gliomas.

The 2021 WHO Classification of Central Nervous System Tumors recommended evaluation of cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) deletion in addition to codeletion of 1p/19q to characterize IDH-mutant gliomas. Here, we demonstrated the use of a nanopore-based copy-number variation sequencing (nCNV-seq) approach to simultaneously identify deletions of CDKN2A/B and 1p/19q. The nCNV-seq approach was initially evaluated on three distinct glioma cell lines and then applied to 19 IDH-mutant gliomas (8 astrocytomas and 11 oligodendrogliomas) from patients. The whole-arm 1p/19q codeletion was detected in all oligodendrogliomas with high concordance among nCNV-seq, FISH, DNA methylation profiling, and whole-genome sequencing. For the CDKN2A/B deletion, nCNV-seq detected the loss in both astrocytoma and oligodendroglioma, with strong correlation with the CNV profiles derived from whole-genome sequencing (Pearson correlation (r) = 0.95, P < 2.2 × 10-16 to r = 0.99, P < 2.2 × 10-16 ) and methylome profiling. Furthermore, nCNV-seq can differentiate between homozygous and hemizygous deletions of CDKN2A/B. Taken together, nCNV-seq holds promise as a new, alternative approach for a rapid and simultaneous detection of the molecular signatures of IDH-mutant gliomas without capital expenditure for a sequencer.

Bulbar dysfunction in normal pressure hydrocephalus: a prospective study.

OBJECTIVE Normal pressure hydrocephalus (NPH) is clinically characterized by gait disturbance, cognitive impairment, and urinary incontinence, as well as enlargement of the ventricles. To the best of the authors' knowledge, there have been no previous publications regarding the correlation between bulbar dysfunction and NPH. The primary objective of this study was to compare preoperative and postoperative prevalence of bulbar dysfunction in patients with NPH. Secondary objectives included assessing the results of surgery for swallowing, speech, gait, cognition, and urination, and evaluating the correlation between bulbar dysfunction and triad symptoms. METHODS Fifty-three patients with NPH who underwent shunt placement surgery at Siriraj Hospital were included in the study. Patients were evaluated for gait, cognition, urination, swallowing, and speech before and 6 months after shunt placement. Triad symptoms were assessed using standard methods. Bulbar dysfunctions were assessed using the Swallowing Problem Questionnaire, Thai Articulation Test, Resonation Screening Test (RST), and Thai Nasality Test. The Thai Speech Assessment Program and nasometer were used for objective speech measurement. RESULTS Preoperatively, 86% (43/50) of patients had swallowing problems and 75% (37/49) had speech problems, as measured by the RST. Postoperatively, there was significant improvement in swallowing (p < 0.001), speech problems by RST (p = 0.008), and voice volume (p = 0.009), but no significant change in the nasometer test. All triad symptoms were improved. There were significant correlations between swallowing impairment and gait disturbance (r = 0.358, p = 0.009), and RST and cognitive impairment (r = -0.502, p < 0.001). CONCLUSIONS This is the first study of bulbar dysfunction in patients with NPH. The results showed that the prevalence of bulbar dysfunction is very high. The correlation between bulbar dysfunction and the classic NPH triad has been documented and published. These bulbar symptoms also significantly improved after surgery. As such, bulbar dysfunction should be regarded as a core symptom that should be considered along with the classic triad in the clinical diagnosis and management of NPH.

Computerized Tomographic Angiography for Detection of Cerebral Vasospasm after Ruptured Intracranial Aneurysm.

OBJECTIVE: Digital subtraction angiography (DSA) is the gold standard to diagnose cerebral vasospasm but it is usually not available due to lack of expertise and proper equipment. The present study aimed to compare the diagnostic accuracy of brain computerized tomographic angiography (CTA) in detecting cerebral vasospasm after intracranial aneurysmal rupture. MATERIAL AND METHOD: Between January 2011 and October 2014, 20 patients who were suspected of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) were prospectively enrolled. All patients underwent brain CTA andDSA within 24 hours after clinical onset ofvasospasm. Separate reviewers independently reviewed the CTA and DSA. RESULTS: Twenty patients were enrolled, including 7 males and 13 females. The patient characteristics did not have any relationship to the incidence of cerebral vasospasm. The CTA finding of vasospasm was well correlated to the DSA finding (Kappa 0.793). Diagnostic accuracy and false negative of the CTA were 90% and 5%, respectively. Sensitivity of the CTA was 94% and specificity was 100%. Positive predictive value ofthe CTA was 100% and negative predictive value was 66%. The vessels that showed the most correlation between the CTA and DSA findings were left A1 (Kappa 0.684) and left A2 (Kappa 0.663) segments of anterior cerebral artery, and left M1 (Kappa 0.503) segment of middle cerebral artery. Both CTA and DSA can detect mild vasospasm (< 50% luminal stenosis) located proximal to the circle of Willis. CONCLUSION: Compared to the DSA, the CTA can be used for detecting cerebral vasospasm in patients with ruptured intracranial aneurysms with high sensitivity, specificity, and diagnostic accuracy.

Sparganosis presenting as cauda equina syndrome with molecular identification of the parasite in tissue sections.

A 52-year-old woman presented with lower back pain, progressive symmetrical paraparesis with sensory impairment, and sphincter disturbance. Magnetic resonance imaging (MRI) of the whole spine revealed multiple intradural extramedullary serpiginous-mass lesions in the subarachnoid space continuously from the prepontine to the anterior part of the medulla oblongata levels, C7, T2-T8, and T12 vertebral levels distally until the end of the theca sac and filling-in the right S1 neural foramen. Sparganosis was diagnosed by demonstration of the sparganum in histopathological sections of surgically resected tissues and also by the presence of serum IgG antibodies by ELISA. DNA was extracted from unstained tissue sections, and a partial fragment of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was amplified using a primer set specific for Spirometra spp. cox1. After sequencing of the PCR-amplicon and alignment of the nucleotide sequence data, the causative agent was identified as the larva of Spirometra erinaceieuropaei.

Predictors of meningioma consistency: A study in 243 consecutive cases.

BACKGROUND: Meningioma is a common neoplasm primarily arising in the central nervous system. Its consistency is considered to be one of the critical prognostic factors for determining surgical resectability. The present study endeavored to investigate predictive factors associated with the tumor consistency. METHODS: Two hundred and forty-three consecutive participants who underwent resective surgery of meningioma were examined. The authors designed an objective grading system for meningioma consistency and utilized it for assessing consistency among all cases. We focused on the relationship between preoperative tumor characteristics on neuroimaging studies and the consistency. RESULTS: The tumor attributes on T2-weighted image (T2WI) and fluid attenuated inversion recovery (FLAIR) image were significantly correlated with the tumor consistency (p = 0.004 and 0.045, respectively). The hypointense tumors on both MRI sequences tended to be hard, whereas the tumors showing hypersignal intensity were associated with soft consistency. There was no correlation between the consistency and age, gender, duration of neurologic symptoms, tumor location, size, calcification, cystic portion, en plague appearance, tumor-brain contact interface expressed by cerebrospinal fluid (CSF) cleft, perilesional vasogenic edema, bony status, features on T1-weighted image (T1WI) and pattern of contrast enhancement. In multiple logistic regression analysis, the tumor characteristics on T2WI and FLAIR image were independent factors significantly correlated with the tumor consistency (p = 0.005 and 0.041, respectively). The tumor consistency was also correlated with operative radicalness as evaluated by the Simpson criteria. CONCLUSIONS: Signal intensity on T2WI and FLAIR image can be used for insinuating meningioma consistency. Presurgical prediction of the consistency is highly valuable in operative planning, particularly in arduous cases.

De novo aneurysm on the posterior cerebral artery: a case report and literature review.

De novo aneurysm formation is a rare entity of cerebral aneurysms. The authors describe a 19-year-old man presenting with spontaneous intracerebral hemorrhage of unknown etiology. The initial cerebral angiography revealed no identifiable vascular lesion. A few weeks following a surgical evacuation of the hematoma, a tiny saccular aneurysm was incidentally found on the distal posterior cerebral artery (PCA) remote from the site of the primary ictus. Several rationales indicated that it was compatible with a cerebral aneurysm of infective etiology. The aneurysm was successfully treated by antibiotic therapy alone. To the authors' knowledge, de novo aneurysm on the PCA has rarely been reported.

Accuracy of various subthalamic nucleus targeting methods and an appropriated formula for Thai patients.

OBJECTIVE: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has recently been the standard surgical treatment for Parkinson's disease. Besides appropriate selection of patients, precise STN targeting is the most crucial factor for good surgical outcomes. However, there is no single targeting method universally accepted as the most accurate technique. Thus, the authors studied the accuracy of various STN targeting methods and proposed a formula for Thai patients. MATERIAL AND METHOD: Sixteen patients with Parkinson's disease who fulfilled the intraoperative criteria of good STN targeting and had significant clinical improvements, without any stimulation-induced adverse effects, were included in the present study. Positions of the STN were determined by four targeting methods, direct targeting by axial T2W MRI, direct targeting by coronal T2W MRI, indirect targeting by anterior commissure-posterior commissure based formula and indirect targeting by adjustable digital Schaltenbrand-Wahren (SW) atlas, were compared with the final lead positions. The final lead positions by the four targeting methods were averaged to get an appropriate AC-PC based formula for Thai patients. RESULTS: The most accurate STN targeting method was axial T2W MRL followed by coronal T2W MRI, AC-PC based formula and the SW atlas, respectively. The averaged final lead positions obtained from the four methods was X = 11.5 +/- 1.0, Y = -3.3 +/- 1.0 and Z = -4.8 +/- 0.42 mm. CONCLUSION: The direct targeting by axial T2W MRI yielded the highest accuracy and the appropriate STN formula for Thai patients appeared to be X = +/- 11.5, Y = -3.5 (-3.3) and Z = -5.0 (-4.8) mm.