Browse

You are looking at 1 - 10 of 40,012 items for

  • Refine by Access: all x
Clear All
Restricted access

Association of disruption of the right posterior arcuate fasciculus with spatial neglect

Mia Andreoli, Mauricio Medina-Pizarro, Melissa-Ann Mackie, and Matthew C. Tate

OBJECTIVE

Spatial neglect is a debilitating condition observed in patients with right-sided brain injuries in whom there is defective awareness of the contralesional space. Although classically considered a right parietal lobe deficit, there has been increasing interest in the specific white matter (WM) architecture subserving spatial neglect. Patients who have lesions associated with chronic disruptions in visuospatial networks are of significant relevance in elucidating the WM tracts associated with spatial attention. In this study, the authors used two independent analytical methods to examine the relationship between WM connectivity changes and spatial attention.

METHODS

Thirty patients with right-sided glioma underwent diffusion tensor imaging (DTI) tractography and neuropsychological testing prior to tumor resection. Spatial neglect was assessed using the Bells Test. Diffusion connectometry analysis was performed to calculate the probability of injury to 55 WM tracts. Next, quantitative DTI tractography was used to reconstruct 9 major WM tracts and obtain fractional anisotropy (FA) and streamline number values as indices of connectivity. Differences in connectivity were assessed between patients with neglect and controls.

RESULTS

Of the WM tracts analyzed by diffusion connectometry, only the right posterior segment of the arcuate fasciculus (psAF) showed a higher probability of disconnection in patients with evidence of hemispatial neglect compared to tract reconstructions of previously published healthy controls (hemineglect: 42% ± 12.5%, vs control: 6.3% ± 4.8% [mean ± SEM]; p < 0.05). Of the WM tracts reconstructed by DTI tractography, only the right psAF demonstrated consistently lower indices of connectivity based on the mean streamline number (hemineglect: 550.35 ± 183.41, vs control: 1407.01 ± 319.93; p < 0.05) and FA value (hemineglect: 0.40 ± 0.013, vs control: 0.44 ± 0.0063; p < 0.05) in patients who demonstrated neglect compared to controls. The right long segment of the arcuate fasciculus, inferior frontooccipital fasciculus, and inferior longitudinal fasciculus also demonstrated a lower streamline number, but not a lower FA value, in patients with evidence of hemineglect.

CONCLUSIONS

These findings suggest that parietotemporal networks mediated by the right psAF may play a critical role in visuospatial attention. This analysis may help to disentangle the organization of the visuospatial attention networks, predict deficits in patients with glioma, and optimize surgical planning.

Restricted access

Biomarkers related to hypertrophy of the ligamentum flavum: a systematic review of the literature

William Mualem, Jiaqi Liu, Alan Balu, Kelsi Chesney, and M. Nathan Nair

OBJECTIVE

Spinal stenosis is one of the most common spinal disorders in the elderly. Hypertrophy of the ligamentum flavum (HLF) can contribute to spinal stenosis. The current literature suggests that various biomarkers may play important roles in the pathogenesis of HLF. However, the connection between these biomarkers and the development of HLF is still not well understood. This systematic review aims to explore the current literature on biomarkers related to the development of HLF.

METHODS

A literature search was conducted using PubMed, Embase, Web of Science, and Cochrane Library. The search strategy looked for the titles, abstracts, and keywords of studies that contained a combination of the following phrases: "ligamentum flavum OR yellow ligament," "biomarkers," and "hypertrophy." Recorded data included study design, demographic characteristics (number of patients of each gender and mean age), study period, country where the study was conducted, biomarkers, and diagnostic modalities used. Risk of bias was assessed using the Newcastle-Ottawa Scale for case-control studies.

RESULTS

The authors identified 39 studies. After screening, 26 full-text original articles assessing one or more biomarkers related to HLF were included. The included studies were conducted over a 22-year period. The most popular biomarkers studied, in order of frequency reported, were collagen types I and III (n = 10), transforming growth factor β (TGF-β) (n = 8), and interleukin (IL)–6 (n = 6). The authors found that mechanical stretching forces, tissue inhibitor of metalloproteinases 2 (TIMP-2) induction, and TGF-β were associated with increased amounts of collagen I and III. IL-6 expression was increased by microRNA-21, as well as by leptin, through the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway.

CONCLUSIONS

Biomarkers such as TGF-β, IL-6, and collagen I and III have been consistently correlated with the development of HLF. However, the pathogenesis of HLF remains unclear due to the heterogeneity of the studies, patient populations, and research at the molecular level. Further studies are necessary to better characterize the pathogenesis of HLF and provide a more comprehensive understanding of how these biomarkers may aid in the diagnosis and treatment of HLF.

Restricted access

Editorial. A plea for surgical equity in the treatment of trigeminal neuralgia

Mojgan Hodaie

Restricted access

Familial Chiari malformation: a systematic review and illustrative cases

Alaina Dhawan, Jillian Dhawan, Ajay N. Sharma, Daniel B. Azzam, Ahmed Cherry, and Michael G. Fehlings

OBJECTIVE

Chiari malformations (CMs) are a group of congenital or acquired disorders characterized by hindbrain overcrowding into an underdeveloped posterior cranial fossa. CM is considered largely sporadic—however, there exists growing evidence of transmissible genetic underpinnings. The purpose of this systematic review of all familial studies of CM was to investigate the existence of an inherited component and provide recommendations to manage and monitor at-risk family members.

METHODS

This paper includes the following: 1) a unique case report of dizygotic twins who presented at the Toronto Western Hospital Spinal Cord Clinic with symptomatic CM type 1 (CM-1) and syringomyelia; and 2) a systematic review of familial CM. The EMBASE and MEDLINE databases were searched on June 27, 2023, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only articles in the English language concerning the diagnosis of CM in > 1 human family member presented as a case study, case series, or literature review were included.

RESULTS

Among the 29 articles included in the final analysis, a total of 34 families with CM were analyzed. An average of 3 cases of CM were found per family among all generations. Eighty-one cases (88%) reported CM-1, whereas the other 11 (12%) cases reported either CM-0, CM-1.5, or tonsillar ectopia. A syrinx was present in 37 (54%) cases, with 14 (38%) of these patients also reporting a skeletal abnormality, the most common comorbidity. Most family members diagnosed with CM were siblings (18; 35%), followed by monozygotic twins/triplets (12; 23%).

CONCLUSIONS

Patients most often presented with headaches, sensory disturbances, or generalized symptoms. Overall, there exists mounting evidence for a hereditary component of CM. It is unlikely to be explained by a classic mendelian inheritance pattern, but is rather a polygenic architecture influenced by variable penetrance, cosegregation, and entirely nongenetic factors. For first-degree relatives of those affected by CM, the authors’ findings may influence clinicians to conduct closer clinical and radiographic monitoring, promote patient education, and consider earlier genetic testing.

Restricted access

How should visual function monitoring be performed and interpreted in surgery for suprasellar tumors?

Atsushi Sato, Toshihiro Ogiwara, Tetsuo Sasaki, Kazuhiro Hongo, and Tetsuyoshi Horiuchi

OBJECTIVE

Preservation of visual function is important in surgery for suprasellar tumors. Visual evoked potentials (VEPs) are expected to play an important role in monitoring visual function during surgery. Given the lack of information in this field, the authors aimed to investigate the effects of optic nerve compression caused by suprasellar tumors to understand the possible usefulness of VEP monitoring using off-response (OFR) VEP.

METHODS

Eleven healthy volunteers who underwent surgery for standard record confirmation and 32 patients with optic chiasm lesions who underwent surgery were examined. Preoperative, postoperative, and intraoperative VEPs were recorded. Propofol anesthesia was administered during intraoperative VEP monitoring. Patients who underwent surgery were monitored using the same stimulation method during surgery. Light stimulation was given from a luminant pad on the eyelids, and low-intensity stimulation with continuous 500-msec emission and 500 msec off was performed. The luminescence intensity of the stimulation was at a maximum of 8000 lx with three attenuation steps, each of which was recorded repeatedly.

RESULTS

The OFR potentials and delay latencies decreased as stimulus intensity decreased. In the patient with temporal hemianopia, monocular stimulation produced the highest OFR in the contralateral occipital lobe of the stimulated eye. The authors recorded preoperative, intraoperative, and postoperative VEP in 32 patients and observed intraoperative changes in 23 patients. In the cases where VEP declined during intraoperative recording, it recovered when surgery was discontinued. Furthermore, 3 patients eventually achieved a higher VEP than that achieved at the beginning of the surgery, and rapid recovery was confirmed with visual field examination immediately after surgery. Of the 5 patients in whom VEP did not recover during surgery, 3 showed decreased visual field and acuity after surgery. In 15 cases, potential dropped temporarily but returned to the original potential, and their visual field recovered after surgery.

CONCLUSIONS

OFR has a diagnostic element in the visual field, in which the maximal potential was recorded on the opposite side of the stimulus with monocular stimulation. Unambiguous determination required stimulation of different intensities in both eyes or 1 eye and multiple recording electrodes placed in the occiput. Monitoring the OFR provides real-time alerts, making it a valuable tool for visual function evaluation in suprasellar surgery.

Restricted access

The impact of regular aspirin use on aneurysm recanalization rates after endovascular coiling

Basel Musmar, Samantha E. Spellicy, Jihad Abdelgadir, Stevie Kraljic, Ali Zomorodi, and David M. Hasan

OBJECTIVE

Intracranial aneurysms (IAs) pose a significant health risk, often leading to subarachnoid hemorrhage and severe neurological outcomes. Endovascular coiling has been a principal treatment method, but it comes with the challenge of high recanalization rates. Aspirin has recently emerged as a potential agent to reduce these rates. In this study, the authors aimed to investigate the impact of regular aspirin use on aneurysm recanalization rates following endovascular coiling in a 10-year single-institution study.

METHODS

A retrospective analysis was conducted on a dataset of 2236 aneurysms treated by a single neurosurgeon over a period of 10 years. The primary outcome measure was aneurysm recanalization, defined by a change in the Raymond-Roy Occlusion Classification of at least one grade.

RESULTS

A total of 525 aneurysms were coiled, 109 of which involved patients who reported regular use of aspirin. The recanalization rate was significantly lower in the aspirin group (9.2%) compared with the control group (23.6%) (OR 0.33, 95% CI 0.15–0.66; p = 0.001). On analysis of the specific mechanisms of recanalization, aneurysm sac growth was less frequent in the aspirin group (5.5%) compared with the control group (18%) (OR 0.265, 95% CI 0.09–0.63; p = 0.002). Additionally, patients in the control group had a higher retreatment rate (18%) than patients in the aspirin group (5.5%) (OR 0.265, 95% CI 0.09–0.63; p = 0.002).

CONCLUSIONS

Regular use of aspirin appears to be associated with reduced rates of aneurysm recanalization after endovascular coiling. However, caution is advised in interpretation of these results given the retrospective nature of this study. Further randomized controlled trials are needed to confirm these findings.

Restricted access

Indirect revascularization for pediatric moyamoya disease

Shotaro Ogawa and Hideki Ogiwara

OBJECTIVE

Indirect revascularization is a common and effective treatment for pediatric moyamoya disease. However, in several cases postoperative angiogenesis is not sufficient. It is not fully understood which factors are involved in the development of postoperative collateral circulation. In this study, the authors aimed to elucidate the factors related to postoperative angiogenesis in indirect revascularization.

METHODS

Among the patients who underwent indirect revascularization for moyamoya disease from January 2015 to December 2022, those whose angiogenesis was evaluated using angiography were included. Age, onset symptoms, comorbidities, preoperative imaging findings, surgical details, perioperative complications, postoperative imaging findings, and modified Rankin Scale (mRS) score at the last outpatient visit were retrospectively examined.

RESULTS

Ninety cases (53 patients; 37 bilateral, 16 unilateral) were included. Sixty-eight cases (75.6%) were symptomatic. The mean age at surgery was 7.9 years, and the mean postoperative follow-up duration was 48.5 months. Frontotemporal encephalo-duro-arterio-synangiosis (EDAS) was performed in all cases, and simultaneous frontal encephalo-galeo-synangiosis (EGS) was performed in 34 cases. Postoperative angiography revealed insufficient angiogenesis in 14 of 90 cases (15.6%) after frontotemporal EDAS and in 8 of 34 cases (23.5%) after frontal EGS. A high degree of ivy sign depicted on preoperative MRI was found to be significantly correlated with good angiogenesis after both surgical procedures (p = 0.00030 for EDAS and p = 0.0039 for frontal EGS). In addition, an advanced preoperative Suzuki stage was significantly correlated with good postoperative angiogenesis after EDAS (p = 0.00040). Good angiogenesis was significantly correlated with postoperative improvement of the ivy sign in both procedures (p = 0.0005 in EDAS and p = 0.030 in frontal EGS) as well as correlated with a better mRS score at long-term follow-up after EDAS (p = 0.018).

CONCLUSIONS

Preoperative ivy sign and Suzuki classification are related to the degree of angiogenesis achieved after indirect revascularization for pediatric moyamoya disease.

Restricted access

Letter to the Editor. Headache relief after anterior decompression: is there really an association?

Jaskeerat Gujral, Om H. Gandhi, Mateusz Bielecki, Fabian Sommer, Rodrigo Navarro-Ramirez, and Pravesh S. Gadjradj

Restricted access

Letter to the Editor. Integrating approaches in motor speech mapping

Justin W. Silverstein, Harshal A. Shah, and Randy S. D’Amico

Restricted access

Letter To The Editor. Redefining parasagittal bridging veins: insights and inquiries from a neurosurgical perspective

Sanford P. C. Hsu, Chun-Fu Lin, and Chih-Hsiang Liao