Angiographic challenges of spinal dural and epidural arteriovenous fistulas: report on 45 cases.

PURPOSE: The localization of the fistula level in spinal dural arteriovenous fistulas (dAVFs) and epidural arteriovenous fistulas (edAVFs) remains a diagnostic challenge. METHODS: Consecutive patients with spinal dAVFs and edAVFs in the thoracic, lumbar, and sacral regions were included. The primary endpoint was to describe the characteristics of patients who required angiography with multiple catheterizations of segmental arteries (10 or more). RESULTS: Forty-five patients (median age 69 years; male 89%; dAVFs, n = 31; edAVFs, n = 14) were included. Spinal dAVFs commonly developed in the thoracic region and edAVFs in the lumbosacral region. Fistulas were predicted at the correct level or plus/minus 2 level in less invasive examinations using multi-detector CT angiography (n = 28/36, 78%) and/or contrast-enhanced MR angiography (n = 9/14, 64%). We encountered diagnostic challenges in the localization of fistulas in 6 patients. They underwent angiography a median of 2 times. In each patient, spinal levels were examined at a median of 25 levels with a median radiation exposure of 3971 mGy and 257 ml of contrast. Fistulas were finally localized at the high thoracic region (T4-6) in 3 patients, the sacral region (S1-2) in 2, and the lumbar region (L3) in 1. Four patients were diagnosed with edAVFs and 2 with dAVFs. The correlation coefficient between the fistula level and the rostral end of the intramedullary T2 high-signal intensity on MRI was interpreted as none. CONCLUSION: In patients in whom less invasive examinations failed for fistula localization, high thoracic or sacral AVFs need to be considered.

Calcified Hofmann's ligaments as the cause of spinal cerebrospinal fluid leaks associated with spinal ventral dural tears.

OBJECTIVE: Patients with spinal CSF leaks often have ventral dural abnormalities (type 1 CSF leaks); however, the pathological mechanism for developing dural abnormalities is unknown. The authors investigated whether calcified dural ligaments contribute to the development of ventral dural tears, which cause spinal CSF leaks. METHODS: Consecutive patients diagnosed with type 1 CSF leaks who had spiculated spinal lesions between 2010 and 2024 were included. Clinical, radiological, surgical, and histological findings were reviewed. RESULTS: Nineteen patients with type 1 CSF fistulas had spiculated spinal lesions (15 men; median age 47 years, range 28-71 years). Spiculated lesions showed a high density on CT, and the median lesion length was 3.5 mm (range 1.6-9.1 mm). Spiculated lesions were consistently located at the center of the ventral dural abnormalities, penetrated the dura mater, and were located in the high thoracic spine (T1-5) in 13 patients (68%) and in the low thoracic spine (T8-12) in 6 (32%). These spinal lesions were connected to the posterior longitudinal ligament, but not to the vertebral body or disc. Histologically, they did not include degenerative osteophytic or discogenic tissues, mostly comprised fibrotic tissues with some calcification, and were consistent with calcified dural ligaments. CONCLUSIONS: The anatomical characteristics of spiculated spinal lesions associated with ventral dural abnormalities are consistent with those of calcified dural ligaments, referred to as Hofmann's ligaments. These ligaments are important for neurosurgeons, neurologists, and neuroradiologists who diagnose and treat type 1 CSF fistulas.

Prevalence, Radiological, and Pathological Findings of Ossification and Calcification of the Lumbar Spinal Ligamentum Flavum: A Comparative Study with Thoracic Lesions.

This study aimed to determine the prevalence of lumbar ligamentum flavum lesions and identify correlations between radiological and pathological findings. We conducted an observational cross-sectional study of 349 patients (lumbar: n = 296, thoracic: n = 39, lumbar and thoracic: n = 14, mean age: 69 ± 12 years, male: 74%) who underwent posterior surgery for thoracolumbar spinal canal stenosis between January 2008 and April 2023 at our hospital.Computed tomography (CT) revealed that the prevalence of ligamentum flavum lesions defined as a high-density area with a CT value of 200 Hounsfield Unit or higher in the lumbar and thoracic spine was 47% (147/310) and 85% (45/53), respectively. CT showed that most patients had radiologically suspected ossification in the lumbar (90%) and thoracic spine (98%) than radiologically suspected calcification. Lumbar lesions were thinner than the thoracic lesions (2.5 vs 3.7 mm, p < 0.01). Pathological examinations were performed in specimens collected from 34 cases (lumbar: n = 13, thoracic: n = 21), and ossification was found in 62% (8/13) and 95% (20/21) of lumbar and thoracic lesions (p = 0.02), respectively. Lastly, ossification was confirmed pathologically in 72% (8/11) and 95% (19/20) of lumbar and thoracic lesions that showed ossification on imaging (p = 0.13), respectively. The literature review revealed that the prevalence of the lumbar ligamentum flavum lesions varied from 1.5 to 35% and the patient population was mostly asymptomatic.Collectively, we found that the prevalence of lumbar ligamentum flavum lesions in symptomatic patients was greater than previously reported. Histologically confirmed ossification was less common in lumbar lesions than in thoracic lesions.

Cerebral Hyperperfusion Syndrome After a Burr Hole Drainage Surgery for Chronic Subdural Hematoma.

BACKGROUND: Although chronic subdural hematoma (CSDH) has a good prognosis after classical minimally-invasive drainage surgery, severe complications still occur at a substantial rate. Cerebral hyperperfusion syndrome (CHS), which is a common severe complication after carotid endarterectomy or carotid artery stenting for cervical carotid artery stenosis, is rare after drainage surgery for a CSDH. CASE DESCRIPTION: We describe the case of an 82-year-old woman who presented with ipsilesional symptoms including contralateral hemiparesis and dysarthria, progressively worsening consciousness, and status epilepticus after a burr hole drainage surgery for CSDH. Magnetic resonance fluid-attenuated inversion recovery imaging showed diffuse subcortical low intensity in the ipsilesional hemisphere almost simultaneously with the appearance of the symptoms. Arterial spin labeling magnetic resonance perfusion imaging showed the abnormal increase of cerebral blood flow in the hemisphere. Continuous propofol administration and blood pressure management improved the symptoms. CONCLUSIONS: CHS can cause severe postoperative complications after drainage surgery for CSDH. Subcortical low-intensity fluid-attenuated inversion recovery imaging is a useful investigation for early detection of CHS in CSDH, and arterial spin labeling imaging is an effective minimally-invasive modality for confirming the diagnosis.