In short

Research on Eagle syndrome consists mostly of case reports, small surgical series and reviews that pool them. There are good anatomical studies of the styloid process and several systematic reviews of treatment, but no randomized trials. Jugular compression has the newest and smallest evidence base.

On this page

Research on Eagle syndrome consists mostly of case reports and small surgical series from single centers, together with systematic reviews that pool them. There are large anatomical studies of the styloid process and several reviews of treatment outcomes, but no randomized trials comparing treatments. The studies below are the ones the pages on Eagle Syndrome Wiki rely on most, grouped by the question they address.

Treatment and outcomes

Three systematic reviews pool published patients. The largest, from 2024, collected 497 patients from 285 reports and compared the classic and vascular forms and their outcomes1. A 2019 review compared surgical approaches and medical treatment2, and a 2025 review focused on patients with vascular complications3. A 2024 meta-analysis compared complication rates between surgery through the mouth and through the neck4, and a 2025 review gathered patients with styloid-related carotid dissection5.

StudyDesignSizePopulationMain findingLimitation
Hassani et al. 2024systematic review497 patients from 285 reportsAdults with Eagle syndrome described in case reports and series published 2000 to 2023.Improvement or resolution in 313 of 320 surgical patients and 81 of 123 treated without surgery.Built from published case reports and single-center series, which favor successful cases. Treatment groups were not randomized, and "improvement or resolution" combines two different outcomes.
Lisan et al. 2019systematic review482 patients in 12 series; 128 in 90 case reportsPublished series and case reports with at least one month of follow-up.Cure in 84.2% after cervical and 73.7% after transoral styloidectomy (series); 91.8% after surgery vs 64.3% after medication (case reports).Based on series and case reports, not trials. "Cure" was defined as disappearance of symptoms, and reporting of complications varied between papers.
Thielen et al. 2025systematic review231 patients from 150 publicationsPatients with Eagle syndrome who had arterial or venous complications.After styloidectomy first, 78.5% cured and 2.5% recurred; after medical treatment first, 24.5% cured and 47.2% recurred.A review of published cases, all selected because complications occurred. It can't estimate how often an elongated styloid causes such complications.
Ferreira et al. 2024meta-analysis36 studies (20 in the meta-analysis)The intraoral approach had the highest complication rate.Pools small observational studies of varying quality; its conclusion differs from the earlier Lisan review.
Klail et al. 2025literature review84 patients in 75 reportsPublished patients with carotid dissection linked to a nearby or elongated styloid process.Symptoms recurred in 33% after conservative treatment and in none treated first with styloidectomy.A narrative review of case reports. Patients chosen for surgery may have differed from those treated conservatively.

Anatomy and imaging

A 2025 meta-analysis of 104 studies established how common styloid elongation is and what the typical length is6. The classification of ossification types used in imaging reports dates from 19867. A 2025 study measured how often dental panoramic X-rays miss elongation8, and a 2026 meta-analysis examined which features of the styloid are linked to carotid dissection9. A 2026 review proposes a framework that groups the neural, arterial and venous forms by mechanism10.

StudyDesignSizePopulationMain findingLimitation
Triantafyllou et al. 2025meta-analysis104 studies; 136,010 sides of the neckAnatomical, radiographic and CT studies of the styloid process from many countries.Elongation (30 mm or longer) on 25.03% of sides; pooled mean length 28.91 mm.Measures anatomy, not symptoms. Studies differed in imaging method, measurement technique and population.
Langlais et al. 1986case report1 patientProposed the elongated, pseudo-articulated and segmented types still used in imaging reports.A descriptive classification illustrated with one case. It describes appearance and doesn't predict symptoms.
Akçiçek et al. 2025diagnostic accuracy study407 patientsDental patients in Ankara who had both panoramic X-rays and cone-beam CT.Panoramic X-rays missed about a third of elongated styloids (sensitivity 64 to 67%).Dental patients, not people with symptoms; one center.
Klail et al. 2026meta-analysis270 patients with dissection, 377 controls (5 studies)Case-control studies comparing styloid anatomy in people with and without carotid dissection.A shorter styloid-to-carotid distance was associated with dissection; styloid length and angle were not.Few, small and varied studies. An association in case-control data doesn't prove that the styloid caused the dissection.
Bănică et al. 2026literature reviewn/aSymptoms depend more on orientation, distance to C1 and vessels, and head position than on length.A narrative review; its classification and treatment strategy are proposals that need testing in prospective studies.

Surgical series

Single-center series report the results of styloidectomy with different approaches: through the neck1112, through the mouth13, robotic surgery through the mouth14, and a mix of approaches15. Most are retrospective, follow patients for months rather than years, and measure success in different ways.

StudyDesignSizePopulationMain findingLimitation
Hardin et al. 2018cohort study21 patientsPatients treated surgically at one US tertiary center, 2011 to 2017.Pain improved in 90% and resolved completely in 62%; first bite syndrome in 24%.Small, retrospective, single-center study.
Fitzpatrick TH 4th, Lovin BD, Magister MJ, Waltonen JD, Browne JD, Sullivan CA 2020case series19 patients, 21 operationsPatients treated at one US academic center, 2000 to 2017; 6 robotic transoral and 15 transcervical resections.90% reported lasting improvement and 55% significant improvement; complications in 3 open cases and no robotic cases.Very small, retrospective and single-center; the robotic group had six operations.
Bargiel et al. 2024cohort study84 patients assessed (97 operated)Patients with classic Eagle syndrome treated in Kraków, 2021 to 2023, with at least six months of follow-up.Significant pain reduction in 94.2% and overall success in 97.1%; all satisfied with the scar.Retrospective, single center, with outcomes collected by questionnaire.
Held et al. 2024case series56 patients; 51 operated; 30 survey responsesAdults diagnosed at one US tertiary center.All 30 survey respondents reported improvement (12) or resolution (18).Retrospective, single surgeon, and only 30 of 51 operated patients answered the survey.
Prasad et al. 2002case series58 patientsPatients with cervicofacial pain and an elongated styloid seen over ten years in India.Transoral surgery with minimal complications and no deep neck infections.Single center, older series; the diagnostic tests weren't compared with a reference standard.

Jugular compression

Compression of the internal jugular vein between the styloid process and C1 has the newest evidence base. A 2012 report of two patients described compression relieved by styloidectomy16, and a 2019 series of 10 patients measured venous pressures and anatomy against a comparison group17. Later reports describe removing the C1 transverse process18, decompressing the vein on all sides19 and moving the carotid artery away from the vein20. Two literature reviews summarize the surgical results2122. A 2024 series reports the results and complications of jugular stenting23, and a hypothesis paper proposes jugular obstruction as a common cause of idiopathic intracranial hypertension24.

Two of these papers are by Dr. Kamran Aghayev, who edits Eagle Syndrome Wiki1920.

StudyDesignSizePopulationMain findingLimitation
Dashti et al. 2012case report2 patientsStyloid removal relieved jugular narrowing and intracranial hypertension in both patients.Two patients.
Zhao et al. 2019case series10 patients, 11 controlsConsecutive patients operated in Phoenix, 2009 to 2017, compared with patients with idiopathic intracranial hypertension and normal venography.9 of 10 improved or resolved after transcervical decompression.Small, retrospective and single-center.
Fritch et al. 2020case report1 patientC1 transverse process resection plus a stent relieved the pressure gradient and symptoms.One patient.
Aghayev et al. 2026case series14 patientsPatients with jugular narrowing between the C1 transverse process and the styloid process; 13 of 14 had both sides decompressed.Vein cross-section roughly 2.5 to 3 times larger after surgery; 9 reported significant and 5 moderate improvement.Retrospective, 14 patients, with improvement self-reported on a subjective scale. Written by Dr. Aghayev, who edits this site.
Aghayev et al. 2026case report1 patientMoving the carotid artery forward and resecting the C1 transverse process resolved all symptoms.One patient. Written by Dr. Aghayev, who edits this site.
Scerrati et al. 2021literature review149 patients in 13 articlesPublished patients with jugular compression by the styloid process or cervical spine.General improvement in 58 of 80 patients with outcome data; complications in 9 of 39 with complication data.Small observational studies with inconsistent reporting; different numbers of patients contribute to each outcome.
Petersingham et al. 2025literature review14 studiesStyloidectomy is the most common operation; no large cohorts or trials exist.A literature review of small studies with varied outcome measures.
Fargen et al. 2024case series29 patients, 33 proceduresPatients with venous outflow disorders stented at one US center, 2019 to 2023; 69% had a connective tissue disorder.About 75% were reported to improve initially; lasting improvement was reported in 12 patients over a mean follow-up of 4.5 months; complications in 11 of 33 procedures (33%).Retrospective, single center, short follow-up.
Fargen et al. 2024hypothesis papern/aProposes that jugular outflow obstruction drives much of idiopathic intracranial hypertension.A hypothesis, not a study. Two authors declare an ownership interest in a company working on venous treatments.

Original descriptions

Watt W. Eagle described two patients with elongated styloid processes in 193725 and the carotid form in 194926. A 2017 review summarizes the presentation, imaging and treatment options for clinicians27.

StudyDesignSizePopulationMain findingLimitation
Eagle 1937original description2 patientsFirst description of the syndrome that now carries the author's name.Two case reports; of historical interest rather than evidence for diagnosis or treatment today.
Eagle 1949original description2 patientsDescribed a second, carotid artery form of the syndrome.Two case reports; the proposed mechanism of carotid-related pain has been questioned since.
Badhey et al. 2017literature reviewn/aCT is the standard test, helped by 3D reconstruction and angiography.A narrative review, not a systematic one.

Why published results differ

Figures for the same operation vary from study to study for reasons that have little to do with the operation itself:

  • What counts as success. Some studies report "cure" (no symptoms), others "improvement", and many reviews combine the two.
  • Who is included. Patients chosen for surgery may have clearer symptoms or a more obvious anatomical cause than those treated with medication.
  • How long patients are followed. Most series follow patients for months; recurrence can come later.
  • What gets published. Case reports and series with good results are more likely to be published than failures.
  • How outcomes are measured. Questionnaires, surgeons' notes and imaging measure different things, and survey response rates are often incomplete.

For these reasons, a success rate from a published series describes the patients in that series. It doesn't predict the result for an individual patient, which depends on how well the diagnosis is established and on the surgeon's experience.

References

  1. Hassani M, Grønlund EW, Albrechtsen SS, Kondziella D. Neurological phenotypes and treatment outcomes in Eagle syndrome: systematic review and meta-analysis. PeerJ. 2024;12:e17423. doi:10.7717/peerj.17423 PubMed ↩
  2. Lisan Q, Rubin F, Werner A, Guiquerro S, Bonfils P, Laccourreye O. Management of stylohyoid syndrome: a systematic review following PRISMA guidelines. Eur Ann Otorhinolaryngol Head Neck Dis. 2019;136(4):281-287. doi:10.1016/j.anorl.2019.05.002 PubMed ↩
  3. Thielen A, Brizzi V, Majoufre C, Nicot R, Schlund M. Eagle syndrome and vascular complications: a systematic review. Int J Oral Maxillofac Surg. 2025;54(1):31-42. doi:10.1016/j.ijom.2024.09.011 PubMed ↩
  4. Ferreira MS, Miranda G, Almeida FT, et al. Complications in intraoral versus external approach for surgical treatment of Eagle syndrome: a systematic review and meta-analysis. Cranio. 2024;42(5):570-582. doi:10.1080/08869634.2021.2020995 PubMed ↩
  5. Klail T, Sachs L, Panos LD, et al. Styloid process-related internal carotid artery dissection: extensive literature review of diagnosis, treatment and outcomes (exemplified with a single-center case series). Neuroradiology. 2025;67(6):1355-1364. doi:10.1007/s00234-025-03616-y PubMed ↩
  6. Triantafyllou G, Paschopoulos I, Duparc F, Tsakotos G, Papadopoulos-Manolarakis P, Piagkou M. The anatomy of the stylohyoid chain: a systematic review with meta-analysis. Diagnostics (Basel). 2025;15(7):925. doi:10.3390/diagnostics15070925 PubMed ↩
  7. Langlais RP, Miles DA, Van Dis ML. Elongated and mineralized stylohyoid ligament complex: a proposed classification and report of a case of Eagle's syndrome. Oral Surg Oral Med Oral Pathol. 1986;61(5):527-532. doi:10.1016/0030-4220(86)90400-7 PubMed ↩
  8. Akçiçek G, Kara D, Uysal S, Zengin HY. Diagnostic accuracy of panoramic radiography in detecting styloid process elongation: a cone-beam computed tomography referenced retrospective study. BMC Oral Health. 2025;25(1):1969. doi:10.1186/s12903-025-07306-2 PubMed ↩
  9. Klail T, Kalioras E, von Gernler M, et al. Anatomical characteristics of the styloid process associated with internal carotid artery dissection: a systematic review and meta-analysis of controlled trials. Front Radiol. 2026;6:1788985. doi:10.3389/fradi.2026.1788985 PubMed ↩
  10. Bănică DA, Zamfirescu VI, Rusu MC, Brezean I. Compression syndromes of the stylohyoid complex: neural, arterial, and venous phenotypes in a dynamic neurovascular corridor. Tomography. 2026;12(9):127. doi:10.3390/tomography12090127 PubMed ↩
  11. Hardin FM, Xiao R, Burkey BB. Surgical management of patients with Eagle syndrome. Am J Otolaryngol. 2018;39(5):481-484. doi:10.1016/j.amjoto.2018.05.003 PubMed ↩
  12. Bargiel J, Gontarz M, Gąsiorowski K, Marecik T, Wyszyńska-Pawelec G. Outcomes of elongated styloid process syndrome treated with minimally invasive cervical styloidectomy (MICS): a single-center retrospective study. J Clin Med. 2024;13(21):6409. doi:10.3390/jcm13216409 PubMed ↩
  13. Prasad KC, Kamath MP, Reddy KJ, Raju K, Agarwal S. Elongated styloid process (Eagle's syndrome): a clinical study. J Oral Maxillofac Surg. 2002;60(2):171-175. doi:10.1053/joms.2002.29814 PubMed ↩
  14. Fitzpatrick TH 4th, Lovin BD, Magister MJ, Waltonen JD, Browne JD, Sullivan CA. Surgical management of Eagle syndrome: a 17-year experience with open and transoral robotic styloidectomy. Am J Otolaryngol. 2020;41(2):102324. doi:10.1016/j.amjoto.2019.102324 PubMed ↩
  15. Held ME, Farsi S, Creighton ERW, Davis KP, King DL, Suen JY. Eagle syndrome presentation and outcomes in a large surgical case series. Laryngoscope Investig Otolaryngol. 2024;9(4):e1289. doi:10.1002/lio2.1289 Source ↩
  16. Dashti SR, Nakaji P, Hu YC, et al. Styloidogenic jugular venous compression syndrome: diagnosis and treatment: case report. Neurosurgery. 2012;70(3):E795-E799. doi:10.1227/NEU.0b013e3182333859 PubMed ↩
  17. Zhao X, Cavallo C, Hlubek RJ, et al. Styloidogenic jugular venous compression syndrome: clinical features and case series. Oper Neurosurg. 2019;17(6):554-561. doi:10.1093/ons/opz012 PubMed ↩
  18. Fritch C, Voronovich Z, Carlson AP. C1 transverse process resection for management of jugular stenosis. Oper Neurosurg. 2020;19(2):E209-E213. doi:10.1093/ons/opaa032 PubMed ↩
  19. Aghayev K, Demir H, Ozdol C, Comella Z, Vrionis FD. Bilateral circumferential internal jugular vein decompression for atlanto-styloid compression syndrome: report of 14 cases. Oper Neurosurg. Published online September 3, 2026. doi:10.1227/ons.0000000000002185 PubMed ↩
  20. Aghayev K, Comella Z, Vrionis FD. Internal carotid artery anterior transposition for internal jugular vein decompression: illustrative case. J Neurosurg Case Lessons. 2026;12(9):CASE26599. doi:10.3171/CASE26599 PubMed ↩
  21. Scerrati A, Norri N, Mongardi L, et al. Styloidogenic-cervical spondylotic internal jugular venous compression, a vascular disease related to several clinical neurological manifestations: diagnosis and treatment, a comprehensive literature review. Ann Transl Med. 2021;9(8):718. doi:10.21037/atm-20-7698 Source ↩
  22. Petersingham G, Shrestha N, Elliott M, et al. Invasive surgical management of cervical internal jugular venous compression: a literature review. J Clin Neurosci. 2025;137:111304. doi:10.1016/j.jocn.2025.111304 PubMed ↩
  23. Fargen KM, Midtlien JP, Belanger K, Hepworth EJ, Hui FK. The promise, mystery, and perils of stenting for symptomatic internal jugular vein stenosis: a case series. Neurosurgery. 2024;95(2):400-407. doi:10.1227/neu.0000000000002891 PubMed ↩
  24. Fargen KM, Midtlien JP, Margraf CR, Hui FK. Idiopathic intracranial hypertension pathogenesis: the jugular hypothesis. Interv Neuroradiol. 2026;32(5):2198-2207. Published online August 8, 2024. doi:10.1177/15910199241270660 PubMed ↩
  25. Eagle WW. Elongated styloid processes: report of two cases. Arch Otolaryngol. 1937;25(5):584-587. doi:10.1001/archotol.1937.00650010656008 DOI ↩
  26. Eagle WW. Symptomatic elongated styloid process; report of two cases of styloid process-carotid artery syndrome with operation. Arch Otolaryngol. 1949;49(5):490-503. doi:10.1001/archotol.1949.03760110046003 PubMed ↩
  27. Badhey A, Jategaonkar A, Anglin Kovacs AJ, et al. Eagle syndrome: a comprehensive review. Clin Neurol Neurosurg. 2017;159:34-38. doi:10.1016/j.clineuro.2017.04.021 PubMed ↩

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