BACKGROUND: Atraumatic subarachnoid haemorrhage (SAH) is associated with high morbidity and mortality. Proposed mechanisms for red blood cell (RBC) clearance from the subarachnoid space (SAS) are erythrolysis, erythrophagocytosis or through efflux along cerebrospinal fluid (CSF) drainage routes. We aimed to elucidate the mechanisms of RBC clearance from the SAS to identify targetable efflux pathways.
METHODS: Autologous fluorescently-labelled RBCs along with PEGylated 40 kDa near-infrared tracer (P40D800) were infused via the cisterna magna (i.c.m.) in female reporter mice for lymphatics or for resident phagocytes. Drainage pathways for RBCs to extracranial lymphatics were evaluated by in vivo and in situ near-infrared imaging and by immunofluorescent staining on decalcified cranial tissue or dural whole-mounts.
RESULTS: RBCs drained to the deep cervical lymph nodes 15 min post i.c.m. infusion, showing similar dynamics as P40D800 tracer. Postmortem in situ imaging and histology showed perineural accumulations of RBCs around the optic and olfactory nerves. Numerous RBCs cleared through the lymphatics of the cribriform plate, whilst histology showed no relevant fast RBC clearance through dorsal dural lymphatics or by tissue-resident macrophage-mediated phagocytosis.
CONCLUSIONS: This study provides evidence for rapid RBC drainage through the cribriform plate lymphatic vessels, whilst neither fast RBC clearance through dorsal dural lymphatics nor through spinal CSF efflux or phagocytosis was observed. Similar dynamics of P40D800 and RBCs imply open pathways for clearance that do not impose a barrier for RBCs. This finding suggests further evaluation of the cribriform plate lymphatic function and potential pharmacological targeting in models of SAH.
BACKGROUND: Swiss National Science Foundation (310030_189226), SwissHeart (FF191155).

BACKGROUND: Stereotactic radiosurgery (SRS) represents a minimally invasive and valuable alternative for jugular foramen schwannomas (JFS), both as upfront and/or adjuvant treatment (in hybrid approaches).
METHODS: We conducted a retrospective review of our cases treated at the Lausanne University Hospital (CHUV) from June 2010 to October 2023. Eleven patients underwent SRS, among whom three had prior surgery, two in our center in the frame of a planned combined approach and one in another center. Two patients received \"volume-staged\" SRS. The mean age at SRS was 60 years (median 68; range 29-83). Cranial nerve (CN) symptoms were present in six patients, while five were asymptomatic. The mean tumor volume at SRS was 2.1 cc (median 1.2; range 0.068-7.3 cc), with a 12 Gy marginal dose prescribed in all cases.
RESULTS: The mean follow-up period was 3.9 years (median 2, range 1-7). Cranial nerve function improved after SRS in six patients, while five remained stable. At the last follow-up, all tumors showed a decrease in volume, except for one patient, who underwent surgery at 18 months after SRS, for volumetric increase at 6 and 12 months, with further XII-th CN palsy and medulla oblongata compression. Although tumor decreased at 18 months, such patient needed microsurgical resection for symptom persistence and was further controlled. The mean tumor volume at 1 year post-SRS was 1.6 cc (median 0.55; range 0.028-7.77 cc), at 2 years was 1.31 cc (median 0.76; range 0.19-5), and at 3 years was 1.32 cc (median 0.59; range 0.23-4.8). No adverse radiation events were observed.
CONCLUSIONS: Stereotactic radiosurgery is considered a safe and effective treatment for jugular foramen schwannomas, ensuring high rates of tumor control in all patients over the long term. The cranial nerve function improved after SRS in the 6 patients who had deficits and the other 5 patients who had no deficits remained asymptomatic. For larger tumors, combined/hybrid approaches can be a valuable alternative, to obtain tumor control and to preserve neurological function.

OBJECTIVE: Cranial nerve (CN) involvement is not a common feature of typical chronic inflammatory demyelinating polyneuropathy (CIDP). Patients with acute presentation of CN palsy in CIDP may be misdiagnosed and treated as other pathologies.
METHODS: We report a patient with multiple cranial neuropathies at the onset of CIDP in detail. In addition, we reviewed a large cohort of patients with CN involvement in CIDP and summarized their characteristics and clinical findings.
RESULTS: We presented a 28-year-old woman who presented with progressive weakness and involvement of CN III, VII, X, XII in the subacute phase who was diagnosed as CIDP and was treated accordingly. A scoping review of the literature resulted in a total of 59 patients with available patient-level data [61.2% men, median age of 32 (Q1-Q3; 20-51.5) years]. CN impairment was present in the acute phase of the polyneuropathy in 10 out of 43 patients (23.3%), while it took a median of 7.7 [Q1-Q3; 3-13] years for other patients to present CN palsy. Sensitivity analysis did not reveal any difference among patients with acute-phase presentation of CN symptoms (N = 11) compared with those with delayed CN palsy (N = 33) in terms of demographics, patterns of CN involvement, associated diminished sensorimotor findings, or relapse. However, patients with acute presentation of CN palsy underwent plasmapheresis approximately 4 times more than those with delayed CN presentations (45.5% vs. 12.1%, P = 0.02).
CONCLUSIONS: In this case presentation and review study, we observed that in one-fourth of patients with CIDP and CN neuropathy, CN involvement occurred in the acute phase. This finding indicates the necessity of considering CIDP among differential diagnoses of patients with CN involvement and polyneuropathies.

We report a case of a 57-year-old man with a tumor arising from the cauda equina with spinal cord and intracranial metastases in the basal cisterns and along the cranial nerves. He presented with severe lower back pain and mild gait imbalance. His imaging revealed a large mass in the lumbosacral region with involvement of the cauda equina, intradural extramedullary enhancing metastases in the thoracic spinal canal, and intracranial metastases in the suprasellar cistern and along both trigeminal and facial/vestibulocochlear nerve complexes. Pathological examination of the resected thoracic spinal cord mass showed an atypical papillary proliferation with moderate nuclear pleomorphism and rare mitotic figures. While the morphologic and immunophenotypic features were consistent with the diagnosis of a choroid plexus tumor, the atypical location for this entity required the exclusion of other epithelioid tumors with papillary architecture. Additional immunohistochemical markers were used to exclude a metastatic adenocarcinoma, a papillary variant of a meningioma, and a papillary variant of an ependymoma. Ultimately, methylation-based tumor profiling determined that the methylation class was a match for \"plexus tumor\" resulting in the integrated diagnosis of the tumor with features of choroid plexus papilloma. This is a unique presentation for both the location and the metastatic spread. The methylation profile was instrumental in establishing this diagnosis.

OBJECTIVE: Neuromodulation approaches have been a part of a revolution in migraine therapies with multiple devices approved or in development. These devices vary in the nerve(s) being targeted, implantable versus noninvasive form factors as well as their effectiveness for acute pain reduction or migraine prevention. This review will summarize these recent advancements and approaches that are being developed which build upon prior work and improved technology that may help enhance the effectiveness as well as the patient experience.
RESULTS: Both noninvasive and implantable devices primarily targeting cranial nerves have shown the ability to help alleviate migraine symptoms. Multiple prospective and retrospective studies have demonstrated clinically meaningful reductions in headache intensity with noninvasive approaches, while prevention of migraine demonstrates more modest effects. Implantable neuromodulation technologies focusing on occipital and supraorbital stimulation have shown promise in migraine/headache prevention in chronic migraine patients, but there is a need for improvements in technology to address key needs for surgical approaches.
CONCLUSIONS: Electrical neuromodulation approaches in the treatment of migraine is undergoing a transformation towards improved outcomes with better technologies that may suit various patient needs on a more individualized basis.

BACKGROUND: Jugular paragangliomas are highly vascularized tumors that can grow in challenging neurovascular compartments and are particularly challenging to resect. There is still no consensus whether preoperative embolization should be employed to minimize intraoperative morbidity.
METHODS: A systematic review and meta-analysis was conducted by searching PubMed, Web of Science, and Embase databases for key terms including \"embolization,\" \"jugular paragangliomas,\" and \"surgery.\"
RESULTS: This review included 25 studies with 706 patients and 475 (67%) preoperative embolizations. Polyvinyl alcohol particles were the most common embolic agent (97.8% of all patients who underwent embolization). Complication rate of embolization was 1% (95% confidence interval [CI]: 0%, 2%). Preoperative embolization was significantly associated with less intraoperative estimated blood loss (mean difference of -7.92 dL [95% CI: -9.31 dL, -6.53 dL]), shorter operating room times (mean difference of -55.24 minutes [95% CI: -77.10 minutes, -33.39 minutes]), and less overall tumor recurrence (odds ratio = 0.23 [95% CI: 0.06, 0.91]) compared with resective surgery alone. Preoperative embolization had no impact on the development of postoperative new cranial nerve deficits not associated with embolization (odds ratio = 1.17 [95% CI: 0.47, 2.91]) and achievement of gross total resection (odds ratio = 1.92 [95% CI: 0.67, 5.53]).
CONCLUSIONS: Preoperative embolization may provide surgical efficiency with faster surgical times and less bleeding and safety with diminished overall recurrence via safe embolization with minimal risks. These results must be considered taking into account the nonrandomness of studies.

BACKGROUND: Assessing pupil size and reactivity is the standard of care in neurocritically ill patients. Anisocoria observed in critically ill patients often prompts further investigation and treatment. This study explores anisocoria at rest and after light stimulus determined using quantitative pupillometry as a predictor of discharge modified Rankin Scale (mRS) scores.
METHODS: This analysis includes data from an international registry and includes patients with paired (left and right eye) quantitative pupillometry readings linked to discharge mRS scores. Anisocoria was defined as the absolute difference in pupil size using three common cut points (> 0.5 mm, > 1 mm, and > 2 mm). Nonparametric models were constructed to explore patient outcome using three predictors: the presence of anisocoria at rest (in ambient light); the presence of anisocoria after light stimulus; and persistent anisocoria (present both at rest and after light). The primary outcome was discharge mRS score associated with the presence of anisocoria at rest versus after light stimulus using the three commonly defined cut points.
RESULTS: This analysis included 152,905 paired observations from 6,654 patients with a mean age of 57.0 (standard deviation 17.9) years, and a median hospital stay of 5 (interquartile range 3-12) days. The mean admission Glasgow Coma Scale score was 12.7 (standard deviation 3.5), and the median discharge mRS score was 2 (interquartile range 0-4). The ranges for absolute differences in pupil diameters were 0-5.76 mm at rest and 0-6.84 mm after light. Using an anisocoria cut point of > 0.5 mm, patients with anisocoria after light had worse median mRS scores (2 [interquartile range 0-4]) than patients with anisocoria at rest (1 [interquartile range 0-3]; P < .0001). Patients with persistent anisocoria had worse median mRS scores (3 [interquartile range 1-4]) than those without persistent anisocoria (1 [interquartile range 0-3]; P < .0001). Similar findings were observed using a cut point for anisocoria of > 1 mm and > 2 mm.
CONCLUSIONS: Anisocoria after light is a new biomarker that portends worse outcome than anisocoria at rest. After further validation, anisocoria after light should be considered for inclusion as a reported and trended assessment value.

OBJECTIVE: Our study aims to investigate three parts of the intracranial cavity, their distances to essential anatomical landmarks, and the correlations between these distances with sex, laterality, and surgical significance.
METHODS: The cranial nerve foraminae and essential surgical landmarks of each fossa were investigated bilaterally in 30 adult formalin-fixed cadaveric heads. Measurements, including lengths, depths, diameters, and horizontal distances to each other, to the midline of the skull, and to the outer lateral margin of the skull, were recorded on both sides.
RESULTS: The optic canal (OC) depth, internal auditory meatus (IAM) width, CNVII and CNIX diameters, and accessory hypoglossal canal (HC) distance were significantly greater on the left side (p < 0.05). CNVI length, CNV diameter, CNXI length, and the distances of the HC and accessory HC from the skull were significantly greater on the right side (p < 0.05). In males, correlations were found between the length of the left CNVIII and the right IAM diameter (r = 0.864, p = 0.001), right CNVIII length (r = 0.709, p = 0.022), right accessory HC length (r = 0.847, p = 0.016), and right-sided skull distance (r = 0.829, p = 0.042). In females, correlations were noted between IAM depth and length, right IAM location relative to the skull, left CNIX and CNX lengths, left CNXII length, left accessory HC location relative to the skull, and accessory HC length.
CONCLUSIONS: The findings of the current study indicate inherent asymmetry, sexual dimorphism, and variability in certain cranial nerves among cadaveric heads, which could have implications for surgical procedures, neuroanatomical studies, and clinical assessments. The study revealed side disparities and correlations within cranial fossa formations and essential surgical landmarks in both genders.

Retropharyngeal infections (RPIs) are uncommon in young infants and are difficult to diagnose due to their non-classical presentation. RPI can occasionally be complicated with multiple cranial nerve palsies but rarely in isolation. Isolated hypoglossal nerve palsy (HNP) due to RPI has been described in the literature but mostly in older children and adults. Assessment for hypoglossal nerve function is challenging in a young infant because the conventional signs of hypoglossal nerve dysfunction are difficult to elicit in this age group. Early recognition and treatment of RPI are associated with good HNP recovery. We present a case of a young infant with tongue deviation and difficulty with feeding attributed to an isolated HNP caused by suppurative retropharyngeal lymphadenitis. The infant underwent incision and drainage with complete recovery of the tongue function after 8 weeks.

BACKGROUND: Supratentorial craniotomy represents the upper part of the combined trans-tentorial or the supra-infratentorial presigmoid approach. In this study, we provide qualitative and quantitative analyses for the supratentorial extension of the presigmoid retrolabyrinthine suprameatal approach (PRSA).
METHODS: The infratentorial PRSA followed by the supratentorial extension craniotomy with dividing and removal of the tentorial strip were performed on both sides of 5 injected human cadaver heads (n = 10 sides). Quantitative analysis was performed for the surface area gained (surgical accessibility) by adding the supratentorial craniotomy. Qualitative analysis was performed for the parts of the brainstem, cranial nerves, and vascular structures that became accessible by adding the supratentorial craniotomy. The anatomical obstacles encountered in the added operative corridor were analyzed.
RESULTS: The supratentorial extension of PRSA provides an increase in surgical accessibility of 102.65% as compared to the PRSA standalone. The mean surface area of the exposed brainstem is 197.98 (standard deviation: 76.222) and 401.209 (standard deviation: 123.96) for the infratentorial and the combined supra-infratentorial presigmoid approach, respectively. Exposure for parts of III, IV, and V cranial nerves is added after the extension, and the surface area of the outer craniotomy defect has increased by 60.32%. Parts of the basilar, anterior inferior cerebellar, and superior cerebellar arteries are accessible after the supratentorial extension.
CONCLUSIONS: The supratentorial extension of PRSA allows access to the supra-trigeminal area of the pons and the lower part of the midbrain. Considering this surgical accessibility and exposure significantly assists in planning such complex approaches while targeting central skull base lesions.