Styloid Process Elongation or Eagle’s Syndrome: Is There Any Role for Ectopic Calcification?

Abstract

The styloid process (SP) is a cylindrical, long cartilaginous bone located on the temporal bone. The normal SP length is approximately 20–30 mm. The styloid process elongation (SPE) can be assumed if either the SP or the adjacent stylohyoid ligament ossification shows an overall length in excess of 30 mm. Elongated SP is known as Eagle’s syndrome when it causes clinical symptoms as neck and cervicofacial pain. It is supposed that this symptoms and signs are due to the compression of the SP on some neural and vascular structures. It may also cause stroke due to the compression of carotid arteries. This syndrome is diagnosed by both radiographical and physical examination. Instead of many hypotheses and studies, the exact etiology of elongated SP and the role of ectopic calcification are unknown. Ectopic calcification (EC) might have a role for the elongation of SP. Abnormal calcium (Ca), phosphorus (P) and vitamin D metabolism is very common in patients with end-stage renal disease (ESRD). Therefore, this calcification in nonosseous soft tissue due to abnormal serum Ca and P levels is commonly associated with this disorder. EC due to the abnormality in this metabolism which is related to the duration of dialysis is also very important for this calcification. Therefore, a study in patients with ESRD investigating the prevalence of SP and the correlation between dialysis period and the SP length may help us explaining the role of EC in the elongation of SP. Because, this disease might be a good model for the investigation of the EC in this elongation. However, further studies and large samples are also needed to clarify the etiology of this disorder.

Morphological assessment of the stylohyoid complex variations with cone beam computed tomography in a Turkish population

“…Putative normal length and prevalence values on previous studies are shown in Table 8. Prevalence of elongated SHC varies between 4.5% and 63.2% in studies which proposed 30 mm as normal length [5,13,18,22,28,30,35,37,40]. Andrei et al [1] determined the normal length of SHC as 35 mm and they reported the prevalence of elongated SHC as 40% in their CBCT study.…”

The importance of medial‐lateral styloid process angulation/coronal plane angle in symptomatic eagle syndrome

“…There is no need to take informed consent, because the data was evaluated retrospectively. (Prasad et al, 2002;Carter, 2004;Jung et al, 2004;Gokce et al, 2008).…”

“…The reason for SPE is not clear (Gokce et al, 2008). It has been suggested that neighboring chronic irritation, surgical injury, endocrine changes in females at menopause, development of the bony tissue, and mechanical anxiety or injury during the development of the SP could bring about calcified hyperplasia of the SP (Balbuena et al, 1997;Fini et al, 2000;Prasad et al, 2002;Gokce et al, 2008).…”

“…The reason for SPE is not clear (Gokce et al, 2008). It has been suggested that neighboring chronic irritation, surgical injury, endocrine changes in females at menopause, development of the bony tissue, and mechanical anxiety or injury during the development of the SP could bring about calcified hyperplasia of the SP (Balbuena et al, 1997;Fini et al, 2000;Prasad et al, 2002;Gokce et al, 2008). Also, the following etiological hypotheses have been proposed: (1) constancy of a cartilaginous precursor of the stylohyoid (one of the embryological antecedents of the styloid) and congenital SPE, (2) calcification of the stylohyoid ligament for obscure reasons, and (3) osseous tissue development at the insertion of the stylohyoid ligament (Balbuena et al, 1997).…”

Prevalence of Elongated Styloid Process and Eagle Syndrome in East Eagean Population

“…Eagle syndrome (ES) which is also known as styloid-carotid artery syndrome, is a rare condition with an elongation of SP or calcification of stylohyoid ligament and clinical symptoms such as neck and cervicofacial pain (1)(2)(3)(4)(5)(6)(7). It was first described by an otorhinolaryngologist, whose name was Eagle, in 1937 (8).…”