persistent stapedial artery

Persistent

stapedial artery • Persistent stapedial artery - Ganzer Fall bei Radiopaedia

O'Donnell, C. Persistent stapedial artery. Case study, Radiopaedia.org. (accessed on 27 Oct 2022) https://doi.org/10.53347/rID-33222 • CC by-nc-sa 3.0 (modified)

An additional

challenge for head and neck radiologists: anatomic variants posing a surgical risk – a pictorial review. Persistent stapedial artery. Axial partitions, TOF sequence with selective venous flow suppression (a–c). A thin arterial structure (arrows) is seen close to the ICA (c) along the promontory (b) and along the tympanic segment of the facial nerve (a). CT of the brain (d,e): coronal multiplanar reformation (MPR) and native axial acquisition. A linear structure runs along the cochlear promontory (arrows), and the left foramen spinosum is absent (black arrowhead points to the right foramen, normally present). Findings are consistent with a persistent stapedial artery

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The persistent stapedial artery (PSA) is an abnormal small vessel arising from the petrous portion of the internal carotid artery and crossing through the middle ear. It results from the failure of regression of the embryonic stapedial artery.

Epidemiology

The prevalence is thought to range from 0.02 to 0.48% in the population.

Clinical presentation

pulsatile tinnitus
conductive hearing loss due to ankylosis of the stapes
sensorineural hearing loss due to an erosion of otic capsule (rare)
mass seen over the promontory in the middle ear while performing an otoscopic examination
incidental finding during surgery that can lead to hemorrhage if not properly identified

Gross anatomy

arises from the proximal hyoid artery at 4-5 weeks of life
passes through the obturator foramen of stapes
branches into upper and lower divisions
posterior division of the upper branch becomes middle meningeal artery
lower branch (maxillomandibular) has two branches
- mandibular artery (becomes inferior alveolar artery in adult)
- infraorbital artery (becomes infraorbital artery in adult)

Anastomosis forms between the ventral pharyngeal artery (precursor of external carotid artery) and lower division of the stapedial artery.

As the ventral pharyngeal artery supplies flow to middle meningeal artery, stapedial artery regresses, leaving small caroticotympanic artery.

It is termed persistent as it is normally found until week 10, at which point flow reverses at the foramen spinosum which in turn induces degeneration over the course of the 3rd fetal month.

Blood supply

Can arise from:

Radiographic features

small canaliculus originating from the petrous segment of the internal carotid artery
linear soft tissue density crossing over the cochlear promontory
enlarged facial nerve canal or separate canal parallel to facial nerve
aplastic or hypoplastic foramen spinosum
- may be a normal variant or in instances where middle meningeal artery arises from the ophthalmic artery

History and etymology

It was first discovered in 1836 at postmortem examination by Austrian anatomist Joseph Hyrtl (1810-1894) , most famous for his description of the tympanomeningeal fissure.

Related pathology

may be associated with aberrant internal carotid artery, which is formed when inferior tympanic artery anastomosis with the caroticotympanic artery; enlarged inferior tympanic canaliculus is then seen
may be associated with other middle ear anomalies