• bone or cartilage anomalies may affect cerebral arteries and cause ischemic stroke (“bony stroke“); however, the association of bone disorders with cerebrovascular diseases is often indirect and accidental
  • mainly, single case reports or small case series have been reported
  • more common in the relatively young patients
  • the following pathomechanisms may contribute:
    • direct affection of the vessel wall resulting in dissection (Eagle syndrome)
    • chronic irritation of a vessel leading to the formation of pseudoaneurysms, which can be a source of arterial embolism
    • hypoperfusion due to arterial stenosis/occlusion/compression (osteopetrosis, Bow-hunter syndrome)
  • each of these mechanisms may be permanent or transient, depending on the specific head position
  • bony strokes are a possible cause of recurrent ischemia of unknown cause in a single vascular territory and may also cause fracture of previously implanted stents
  • the diagnosis of a bony stroke is based on a combination of medical history and imaging modalities (CT/MR angiography, ultrasound of brain-supplying vessels)
    • dynamic imaging modalities (ultrasound, CTA, or even DSA) with the patient’s head in a fixed rotation or reclination can help detect transient compressive disorders
    • competing etiologies of ischemic stroke should be sufficiently excluded, and contact between a bone or cartilage anomaly and the affected vessel should be demonstrated
  • treatment options require a multidisciplinary approach and include:
    • conservative treatment
    • endovascular stenting
    • occlusion of the affected vessel
    • surgical bypass
    • bone/cartilage removal
  • correct diagnosis and timely treatment may eliminate the risk of stroke recurrence and significantly impact the patient’s long-term outcome; prospective trials are needed to optimize care

Fibrocartilaginous emboli

  • embolization (spinal or intracranial) can very rarely result from a ruptured nucleus pulposus

Skull disorders

  • osteopetrosis (OP) is a rare, inherited metabolic disorder of unknown etiology, characterized by abnormal accumulation of bone mass, probably due to reduced bone resorption
    • cerebrovascular involvement is quite rare; strokes can occur due to arterial compression caused by the mechanical constriction of the basal foramina from the osteopetrotic bone
  • cerebrovascular disorders in patients with Paget´s disease are mainly of mechanical origin
  • spondyloepiphyseal dysplasia –  an autosomal recessive disorder where cerebral ischemia, associated with the moyamoya phenomenon, has been reported

Vascular Eagle syndrome

  • a condition associated with the contact of the ICA with the elongated styloid process or a calcified stylohyoid ligament
  • clinically characterized by throat and neck pain that radiates to the ear; rarely, it may cause carotid dissection  Eagle´s syndrome - elongated styloid process may cause direct mechanical damage to the carotid artery  (Ogura, 2015) (Saccomanno, 2018)
  • in cases where dissections are treated with stenting, an unrecognized elongated styloid process may cause subsequent stent fracture  (Haertl, 2023)

Spine and neck anomalies

Bow-Hunter syndrome

  • Bow Hunter’s syndrome (also known as Rotational vertebral artery occlusion syndrome) is a condition characterized by symptomatic vertebrobasilar insufficiency, typically transient, resulting from the mechanical compression of the vertebral artery at the atlanto-axial joint during head rotation within the normal physiological range
  • in DDx exclude compression by the thyroid cartilage (see below)

Vertebral artery affection by a bony spur

  • bony spur is a rare cause of recurrent posterior circulation strokes
  • it usually can be detected on a CT scan
  • in some cases (recurrent stroke despite best medical treatment), endovascular occlusion of the vessel may be performed

Vertebral artery compression from the thyroid cartilage

  • VA compression in the V2 segment due to thyroid cartilage may cause recurrent posterior circulation ischemic strokes
  • in some cases, the lesion may not become apparent until the stent is deployed and its compression by the thyroid cartilage is documented
  • close anatomic relationship to the thyroid cartilage may become more pronounced during swallowing and/or head rotation (dynamic imaging)
  • surgical treatment options:
    • surgical removal of the thyroid cartilage
    • surgical bypass to the V3 segment with occlusion of the V2 segment

Periodontal disorders

  • periodontal disease is highly prevalent
    • gingivitis, the mildest form of periodontal disease, is caused by the bacterial biofilm (dental plaque) that accumulates on the teeth adjacent to the gingiva
    • periodontitis results in loss of connective tissue and bone support and is a significant cause of tooth loss in adults
  • periodontitis appears to be an independent risk factor for cardiovascular disease and ischemic stroke  (Leng, 2023)  (Karnoutsos, 2008)
  • the association has several possible pathophysiologic links:
    • increased risk of thrombosis induced by periodontal pathogens
    • accelerated atherosclerosis (periodontal bacteria have been found in the atheromatous plaques and can influence cardiovascular risk factors, such as lipids, fibrinogen, and C-reactive protein)

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Bone and cartilage disorders and stroke
link: https://www.stroke-manual.com/bone-disorders-and-stroke/