Absent pyramidal eminence and stapedial tendon associated with congenital stapes footplate fixation: Intraoperative and radiographic findings

OBJECTIVE

Report an association between congenital stapes footplate fixation (CSFF) and radiological absence of the pyramidal eminence and stapedial tendon.

PATIENTS

Children and adults with intraoperatively confirmed CSFF and an absent stapedial tendon.

INTERVENTIONS

Computed tomography (CT); exploratory tympanotomy with stapedotomy.

MAIN OUTCOME MEASURES

Absence of a pyramidal eminence and stapedial tendon aperture identified on preoperative CT that was confirmed intraoperatively.

RESULTS

Eight patients with intraoperative confirmation of CSFF and absent stapedial tendon were retrospectively identified. The average preoperative bone conduction and air conduction pure tone averages were 19.6 dB (SD 15.6 dB) and 55.9 dB (SD 23.6 dB), respectively. The average air-bone gap was 36.3 dB (SD 17.9 dB) preoperatively. In the seven patients who underwent preoperative CT, all were consistently identified to have an absent or hypoplastic pyramidal eminence and absent stapedial tendon aperture at the pyramidal eminence. In six cases, the stapedial footplate appeared normal, while in one case the footplate appeared abnormal which correlated with severe facial nerve prolapse observed intraoperatively. All eight cases underwent exploratory tympanotomy and demonstrated intraoperative stapes footplate fixation, absent stapedial tendon and either absent or hypoplastic pyramidal eminence, which correlated with preoperative CT findings.

CONCLUSIONS

This study identifies a clinically pragmatic association between an absent pyramidal eminence identified on high-resolution CT and the diagnosis of CSFF. In a condition that otherwise generally lacks distinctive radiological features, the absence of a pyramidal eminence on CT in a patient with nonprogressive, congenital conductive hearing loss may strengthen clinical suspicion for CSFF.

The extent of inferior displacement of the mastoid tegmen is related to the severity of congenital aural atresia

CONCLUSION

The extent of inferior displacement of the mastoid tegmen is related to the severity of congenital aural atresia (CAA).

OBJECTIVE

To analyze anatomic variations observed on high-resolution temporal bone computed tomography (TBCT) in patients with CAA, the extent of inferior displacement of the mastoid tegmen and the size of the incudo-stapedial (IS) joint angle were compared with surgical parameters for atresiaplasty, such as Jahrsdoerfer score and hearing acuity.

METHODS

Sixty-one patients with unilateral CAA underwent high-resolution TBCT and hearing tests. We evaluated TBCTs in terms of Jahrsdoerfer criteria and analyzed the relationships among the inferior displacement of the mastoid tegmen, size of the IS joint angle, hearing acuity, and the Jahrsdoerfer score on the atretic side.

RESULTS

IS joint angle on the atretic side was found to be 120.6 ± 11°, which was significantly greater than the corresponding value of 103.4 ± 5.4° on the normal side. Cholesteatoma occurred significantly more often in CAA patients with narrow external auditory canals (EACs) (9/27; 33.3%), compared with CAA patients with no EAC opening (2/34; 5.9%). There was a significant relation between the extent of inferior displacement of the mastoid tegmen (28.9% in the atretic side and 17.3% in the normal side) and the Jahrsdoerfer score (p < 0.0001).

[Morphodifferentiation of the stapedius muscle. Personal contribution]

The aim of this study is to explain the origin of the anomalies and variations that affect the muscle-tendon complex of the stapes. These are interpreted from the model of the stapes muscle differentiation formed by two independent anlagen (Rodríguez-Vázquez, 2005, 2009 and Rodríguez-Vázquez et al., 2010): one for the belly muscle, located on the second branchial arch medially to the facial nerve; and another for the tendon, formed from the internal segment of interhiale. The external segment of the interhiale usually disappears. The pyramidal eminence is organized from the mesenchymal condensation sorrounding the muscle belly, which is independent of the second branchial arch cartilage.

Congenital stapedial fixation associated with Beckwith--Wiedemann syndrome: two cases of a woman and her brother

Beckwith-Wiedemann syndrome (BWS) is characterized by the triad of exophthalmos, macroglossia, and gigantism (EMG syndrome) presented at birth. Two patients with BWS, a woman and her younger brother, who presented with conductive deafness caused by middle ear anomaly are reported. Stapedial fixations were confirmed by tympanotomy, and satisfactory hearing improvements were obtained by small fenestra stapedectomy. Hearing loss associated with BWS has not previously been reported. Characteristic sulci on the auricular lobe of BWS are thought to be caused by malposition of the antitragus, which originates from the second branchial arch. Stapedial fixation might be due to maldevelopment of the stapedial lamina, which also originates from the second branchial arch. There could be a causal relationship between stapedial fixation and BWS.

Stapedius tendon ossification: a rare cause of congenital conductive hearing loss

Two cases are presented of bilateral conductive deafness in siblings. An initial presumptive diagnosis of otosclerosis was made in the first case, that of a nine-year-old girl with a bilateral hearing loss of 45 dB. Exploratory tympanotomy revealed normal ossicles but the stapedius 'tendon' was found to be a solid bony bar fixing the stapes. Division of the 'tendon' resulted in normal ossicular mobility and return of hearing with closure of the air-bone gap. Identical ossification was found in her other ear, and some years later in both ears of one of her brothers. Similar surgery restored hearing successfully in each case. An acquired aetiology has been proposed in one of the three previously reported cases; this report, however, suggests the congenital nature of the anomaly. No previous cases have been described occurring in siblings.