Persistent stapedial artery with ankylosis of the stapes footplate.
The patient gave consent for middle ear exploration and stapedectomy. His malleus and incus were mobile. A large, pulsating vessel was found passing through the crura of the stapes, consistent with a persistent stapedial artery (PSA) (figure 2). His stapes footplate was found to be fixed. Because of the large PSA, stapedectomy was abandoned, despite the presence of a fixed stapes.
Postoperatively, the CT images were reviewed and the lucency that had previously been identified on the stapes footplate was determined to be a PSA. The patient also was noted to have an absent foramen spinosum, one of the features of PSA (figure 3).
Given the position and size of the patient's PSA, his treatment options were either hearing aids or ablation of the PSA followed by a stapedotomy. Because of the theoretical risks of ablation, including bleeding and injury to the facial nerve, the patient decided to use hearing aids to manage his conductive hearing loss.
PSA is a rare congenital vascular anomaly with a prevalence of 0.02% to 0.5%.' It may present as a pulsatile middle ear mass or may appear as an incidental finding during middle ear surgery. Most patients with a PSA are asymptomatic. The classic CT findings suggestive of a PSA include a soft-tissue prominence in the region of the tympanic segment of the facial nerve and the absence of the ipsilateral foramen spinosum. These findings also can include a small canaliculus originating from the carotid canal and enlargement of the tympanic segment of the facial nerve canal or a separate canal paralleling the facial nerve.
In the present case, the presence of the soft tissue on the stapes footplate initially gave the appearance of an otosclerotic plaque. This case illustrates an unusual presentation of a PSA and demonstrates the importance of thorough middle ear assessment in the management conductive hearing loss.
(1.) Moreano EH, Paparella MM, Zelterman D, Goycoolea MV. Prevalence of facial canal dehiscence and of persistent stapedial artery in the human middle ear: A report of 1000 temporal bones. Laryngoscope 1994;104(3 Pt l):309-20.
Fiona C.E. Hill, MBBS; Bing Teh, MBBS; Michael Tykocinski, FRACS
From the Department of Otolaryngology Head and Neck Surgery, The Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia (Dr. Hill and Mr. Tykocinski); and the Department of Otolaryngology Head and Neck Surgery, The Alfred Hospital, Melbourne, Victoria, Australia (Dr. Bing and Mr. Tykocinski). The case described in this article occurred at The Alfred Hospital.
Caption: Figure 1. CT demonstrates the opacification over the stapes footplate (arrow), originally reported as a sclerotic plaque but determined to be a PSA.
Caption: Figure 2. In this photograph down the external auditory canal with the tympanic membrane elevated, the pulsatile stapedial artery can be seen running over the stapes footplate, between the anterior and posterior crura. The stapedius tendon and chorda tympani nerve are seen in the foreground.
Caption: Figure 3. CT reveals the bilateral foramen ovale (red arrows) and the foramen spinosum on the left (yellow arrow), which is absent on the right.
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|Title Annotation:||OTOSCOPIO CLINIC|
|Author:||Hill, Fiona C.E.; Teh, Bing; Tykocinski, Michael|
|Publication:||Ear, Nose and Throat Journal|
|Date:||Aug 1, 2018|
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