Reappraisal of the Previously Described False Localizing Sign at C1-2 in Cases of Spontaneous Intracranial Hypotension.

BACKGROUND AND OBJECTIVES: We present an illustrative case of spontaneous intracranial hypotension (SIH) in the setting of a suspected C1-2 cerebrospinal fluid (CSF) leak that was successfully treated with muscle, collagen, and epidural blood patch. We examined the literature to identify similar cases reporting Cl-2 retrospinal fluid collections identified on imaging in the setting of SIH and quantified the success of targeted treatment to this area despite previous reports that caution about a "C1-2 false localizing sign." METHODS: A systematic search was performed identifying cases of SIH resulting from CSF leak with C1-2 fluid collection observed on imaging. PubMed, Google Scholar, and Web of Science were queried, and articles were screened for possible inclusion by 2 authors and supervised by the senior author. RESULTS: In total, 28 studies were included with a total of 32 patients. The number of patients in each study with C1-2 fluid collections, number of patients with fluid collections at multiple levels, specific intervention used, and outcomes of each intervention were recorded, with a focus on whether treatment occurred at the levels exhibiting fluid signal. CONCLUSION: Although the C1-2 fluid signal in SIH has previously been described as a "false localizing sign," our study indicates that treating this level as the source of CSF leak results in successful and durable outcomes. Most SIH cases with signal at C1-2 did not have a fluid signal at any other level and were treated successfully and most commonly through epidural blood patch at the C1-2 level. Symptom resolution was also reported after direct repair of C1-2 CSF leaks through primary closure, Gelfoam patch, and muscle fragment with fibrin. In patients with SIH, C1-2 fluid signal, and no other source of CSF leak identified on imaging, surgical intervention at the C1-2 level seemed to have a high success rate.

Timing of diffusion tensor imaging in the management of a ruptured pediatric arteriovenous malformation: illustrative case.

BACKGROUND: Diffusion tensor imaging (DTI) can characterize eloquent white matter tracts affected by brain arteriovenous malformations (AVMs). However, DTI interpretation can be difficult in ruptured cases due to the presence of blood products. The authors present the case of a ruptured pediatric AVM in the corticospinal tract (CST) and discuss how DTI at different time points informed the treatment. OBSERVATIONS: A 9-year-old female presented with a sudden headache and left hemiparesis. She was found to have a Spetzler-Martin grade III, Supplementary grade I AVM in the right caudate and centrum semiovale, with obliteration and corresponding reduced fractional anisotropy (FA), fiber density (FD), and tract count (TC) of the adjacent CST on DTI. The patient remained stable and was scheduled for elective resection following a 6-week period to facilitate hematoma resorption. After 6 weeks, repeat DTI showed part of the nidus within intact CST fibers with concordant improvement in FA, FD, and TC. Considering the nidus location, CST integrity, and motor function recovery, surgery was deferred in favor of stereotactic radiosurgery. LESSONS: In ruptured AVMs, DTI may initially create an incomplete picture and false assumptions about white matter tract integrity. DTI should be repeated if delayed treatment is appropriate to ensure informed decision-making and prevent avoidable permanent neurological deficits. https://thejns.org/doi/10.3171/CASE24225.

Single-level laminoplasty approach to selective dorsal rhizotomy with conus localization by rapid spine MRI.

INTRODUCTION: While selective dorsal rhizotomy (SDR) was originally described as a multilevel approach, single-level approaches are now popularized. Conus localization is beneficial for operative planning in single-level selective dorsal rhizotomy. Our approach to SDR involves minimal exposure for a single-level laminoplasty, preserving one attached interspinous ligament. Pre-operative conus localization is required for this tailored approach to determine the laminoplasty level and dictate rostral or caudal division of the superior spinus ligament. While rapid MRI sequences have been popularized for pediatric cranial imaging, its utility for spinal imagining is less well-described, and specific application for conus localization has not been reported. OBJECTIVE: Illustrate that rapid MRI without sedation is sufficient to identify conus level for tailored single-level laminoplasty SDR. MATERIAL AND METHODS: Patients undergoing SDR from 2014 to 2022 at one institution were reviewed for type of pre-operative MRI (rapid vs full), conus level, procedural time for MRI, and radiology report. The typical rapid MRI has four sequences utilizing single-shot technique (scout, sagittal T2, axial T2, and axial T1) that typically take less than 1 min each of acquisition time, with non-single-shot sequences added periodically in cooperative patients. To include time for patient positioning, pre-scan shimming, procedural incidentals, and other patient-specific variations, MRI procedure length was recorded as documented in the electronic medical record. RESULTS: N = 100 patients had documentation of an MRI for pre-operative imaging. Seventy-nine of these had a rapid MRI, and 21 required a full MRI with anesthesia for their treatment plan. Mean total procedure time for rapid MRI was 21.5 min (median 17). Mean procedure time for MRI under general anesthesia was 91.2 min (median 94). Of patients with rapid MRI imaging, 2/79 had an ambiguous conus level (1 from motion artifact, 1 from spinal hardware) vs 1/21 with a full MRI under anesthesia (due to spinal hardware). CONCLUSION: Rapid spinal MRI without sedation can be used for conus localization in a pediatric population. This may be routinely used as pre-operative imaging for a single-level approach to selective dorsal rhizotomy, without sedation or intubation procedures.

Blood Pressure and Spot Sign in Spontaneous Supratentorial Subcortical Intracerebral Hemorrhage.

BACKGROUND: Spontaneous intracerebral hemorrhage is a potentially devastating cause of brain injury, often occurring secondary to hypertension. Contrast extravasation on computed tomography angiography (CTA), known as the spot sign, has been shown to predict hematoma expansion and worse outcomes. Although hypertension has been associated with an increased rate of the spot sign being present, the relationship between spot sign and blood pressure has not been fully explored. METHODS: We retrospectively analyzed data from 134 patients (40 women and 94 men, mean age 62.3 ± 15.73 years) presenting to a tertiary academic medical center with spontaneous supratentorial subcortical intracerebral hemorrhage from 1/1/2018 to 1/4/2021. RESULTS: A spot sign was demonstrated in images of 18 patients (13.43%) and correlated with a higher intracerebral hemorrhage score (2.61 ± 1.42 vs. 1.31 ± 1.25, p = 0.002), larger hematoma volume (53.49cm3 ± 32.08 vs. 23.45cm3 ± 25.65, p = 0.001), lower Glasgow Coma Scale on arrival (9.06 ± 4.56 vs. 11.74 ± 3.65, p = 0.027), increased risk of hematoma expansion (16.67% vs. 5.26%, p = 0.042), and need for surgical intervention (66.67% vs. 15.52%, p < 0.001). We did not see a correlation with age, sex, or underlying comorbidities. The presence of spot sign correlated with higher modified Rankin scores at discharge (4.94 ± 1.00 vs. 3.92 ± 1.64, p < 0.001). We saw significantly higher systolic blood pressure at the time of CTA in patients with a spot sign (184 mm Hg ± 43.11 vs. 153 mm Hg ± 36.99, p = 0.009) and the highest recorded blood pressure (p = 0.019), although not blood pressure on arrival (p = 0.081). Performing CTA early in the process of blood pressure lowering was associated with a spot sign (p < 0.001). CONCLUSIONS: The presence of spot sign correlates with larger hematomas, worse outcomes, and increased surgical intervention. There is a significant association between spot sign and systolic blood pressure at the time of CTA, with the highest systolic blood pressure being recorded prior to CTA. Although the role of intensive blood pressure management in spontaneous intracerebral hemorrhage remains a subject of debate, patients with a spot sign may be a subgroup that could benefit from this.

Early Minimally Invasive Parafascicular Surgery for Evacuation of Spontaneous Intracerebral Hemorrhage in the Setting of Computed Tomography Angiography Spot Sign: A Case Series.

BACKGROUND: Spontaneous intracerebral hemorrhage (sICH) is associated with high morbidity and mortality, and the role of surgery is uncertain. Spot sign on computed tomography angiography (CTA) has previously been seen as a contraindication for minimally invasive techniques. OBJECTIVE: To demonstrate the use of minimally invasive parafascicular surgery (MIPS) for early evacuation of sICH in patients with spot sign on CTA. METHODS: Retrospective review of patients presenting to a US tertiary academic medical center from 2018 to 2020 with sICH and CTA spot sign who were treated with MIPS within 6 h of arrival. RESULTS: Seven patients (6 men and 1 woman, mean age 54.4 yr) were included in this study. There was a significant decrease between preoperative and postoperative intracerebral hemorrhage volumes (75.03 ± 39.00 cm3 vs 19.48 ± 17.81 cm3, P = .005) and intracerebral hemorrhage score (3.1 ± 0.9 vs 1.9 ± 0.9, P = .020). The mean time from arrival to surgery was 3.72 h (±1.22 h). The mean percentage of hematoma evacuation was 73.78% (±21.11%). The in-hospital mortality was 14.29%, and the mean modified Rankin score at discharge was 4.6 (±1.3). No complications related to the surgery were encountered in any of the cases, with no abnormal intraoperative bleeding and no pathology demonstrating occult vascular lesion. CONCLUSION: Early intervention with MIPS appears to be a safe and effective means of hematoma evacuation despite the presence of CTA spot sign, and this finding should not delay early intervention when indicated. Intraoperative hemostasis may be facilitated by the direct visualization provided by a tubular retractor system.

Technical notes on the placement of cerebral microdialysis: A single center experience.

Background: Cerebral microdialysis enables monitoring of brain metabolism and can be an important part of multimodal monitoring strategies in a variety of brain injuries. Microdialysis catheters can be placed in brain parenchyma through a burr hole, a cranial bolt, or directly at the time of an open craniotomy or craniectomy. The location of catheters in relation to brain pathology is important to the interpretation of data and guidance of interventions. Methods: Here we retrospectively review the use of cerebral microdialysis at a US Regional Medical Center between March 2018 and February 2022 and provide detailed descriptions and technical nuances of the different methods to place microdialysis catheters. Results: Eighty two unique microdialysis catheters were utilized in 52 patients. 35 (42.68%) were placed via a quad-lumen bolt and 47 (57.32%) were placed through craniotomies. 27 catheters (32.93%) were placed in a perilesional location, 50 (60.98%) were located in healthy tissue, and 6 (7.32%) were mispositioned. No significant difference was seen between placement by bolt or craniotomy in regard to perilesional location, mispositioning, or complications. Conclusion: With careful planning and thoughtful execution, cerebral microdialysis catheters can be successfully placed though a variety of strategies to optimize and individualize brain monitoring in different clinical settings. This paper provides a detailed guide for the various methods of catheter placement to help providers begin or expand their use of cerebral microdialysis.

A Noninvasive Retrograde Flushing System for Shunted Hydrocephalus: Initial Case Series of 25 Patients.

Hydrocephalus is a common neurosurgical pathology associated with high patient morbidity and systemwide healthcare costs. A significant portion of these costs are related to the failure of ventricular shunting systems. Despite decades of research and technological development, the rate of shunt failure and revision has not significantly improved. The Reflow™ Ventricular System (Anuncia, Inc., Lowell, MA) is a recent technological development with the potential to prolong the shunt lifespan. This system introduces a noninvasive means of flushing a shunt proximally with a controlled, repeatable pulse of cerebral spinal fluid (CSF) and of creating a new ventricular opening for occluded shunts. In this multicenter case series, we present the early clinical experiences with this device and discuss its potential.

Intranasal administration as a route for drug delivery to the brain: evidence for a unique pathway for albumin.

A variety of compounds will distribute into the brain when placed at the cribriform plate by intranasal (i.n.) administration. In this study, we investigated the ability of albumin, a protein that can act as a drug carrier but is excluded from brain by the blood-brain barrier, to distribute into the brain after i.n. administration. We labeled bovine serum albumin with [(125)I] ([(125)I]Alb) and studied its uptake into 11 brain regions and its entry into the blood from 5 minutes to 6 hours after i.n. administration. [(125)I]Alb was present throughout the brain at 5 minutes. Several regions showed distinct peaks in uptake that ranged from 5 minutes (parietal cortex) to 60 minutes (midbrain). About 2-4% of the i.n. [(125)I]Alb entered the bloodstream. The highest levels occurred in the olfactory bulb and striatum. Distribution was dose-dependent, with less taken up by whole brain, cortex, and blood at the higher dose of albumin. Uptake was selectively increased into the olfactory bulb and cortex by the fluid-phase stimulator PMA (phorbol 12-myristate 13-acetate), but inhibitors to receptor-mediated transcytosis, caveolae, and phosphoinositide 3-kinase were without effect. Albumin altered the distribution of radioactive leptin given by i.n. administration, decreasing uptake into the blood and by the cerebellum and increasing uptake by the hypothalamus. We conclude that [(125)I]Alb administered i.n. reaches all parts of the brain through a dose-dependent mechanism that may involve fluid-phase transcytosis and, as illustrated by leptin, can affect the delivery of other substances to the brain after their i.n. administration.