Gruber's Ligament is a Part of the Dura Mater: An Anatomical and Histological Study of Dorello's Canal Relevant to Skull Base Surgery

Abstract

Objective

Many studies have focused on Gruber's ligament and Dorello's canal. However, only scant studies have analyzed these structures via histological analysis. Furthermore, the histology studies for these structures did not sufficiently evaluate them and their surrounding anatomical relationships. Therefore, this study aims to assess the comprehensive morphology of Gruber's ligament and Dorello's canal.

Methods

Histological observation in coronal and sagittal sections and microsurgical observations (using both conventional and inferior approaches) were conducted on Gruber's ligament, Dorello's canal, and related structures.

Results

Histological observation revealed that the only extension of the dura was found between the petrous apex and the clivus. Microsurgical dissection using the conventional approach identified a fibrous band, whereas the inferior approach did not reveal any distinct connective tissue other than dura. Our multidirectional approach demonstrated that Gruber's ligament is part of the dura between the petrous apex and clivus. The petrous apex end was artificially separated from the dura along the medial wall of the cavernous sinus. The previously reported variations of Gruber's ligament, such as duplication or absence, can now be explained by our findings.

Conclusion

Gruber's ligament is simply a part of the dura at the skull base. The extension of the dura between the petrous apex and clivus, which forms part of a mesh-like structure rather than a distinct ligament, traditionally has been termed Gruber's ligament.

Keywords

Dorello's canal - Gruber's ligament - dura - abducens nerve - anatomy - cadaver - petroclinoid ligament - petrosphenoidal ligament - petroclival ligament

• References

• 1 Plutecki D, Ostrowski P, Bonczar M. et al. The petroclinoid ligament: a meta-analysis of its morphometry and prevalence of mineralization with a review of the literature. Folia Morphol (Warsz) 2023; 82 (03) 487-497
• 2 Ekanem UI, Chaiyamoon A, Cardona JJ. et al. Prevalence, laterality, and classification of ossified petroclival ligaments: an anatomical and histological study with application to skull base surgery. Cureus 2023; 15 (03) e36469
• 3 Gutierrez S, Khan PA, Iwanaga J, Dumont AS, Tubbs RS. Review of the petroclinoid ligament. Kurume Med J 2022; 67 (01) 5-10
• 4 Iwanaga J, Altafulla JJ, Gutierrez S. et al. The petroclinoid ligament: its morphometrics, relationships, variations, and suggestion for new terminology. J Neurol Surg B Skull Base 2020; 81 (06) 603-609
• 5 Wysiadecki G, Radek M, Tubbs RS. et al. Microsurgical anatomy of the inferomedial paraclival triangle: contents, topographical relationships and anatomical variations. Brain Sci 2021; 11 (05) 596
• 6 Özgür A, Esen K. Ossification of the petrosphenoidal ligament: multidetector computed tomography findings of an unusual variation with a potential role in abducens nerve palsy. Jpn J Radiol 2015; 33 (05) 260-265
• 7 Inal M, Muluk NB, Burulday V. et al. Investigation of the calcification at the petroclival region through multi-slice computed tomography of the skull base. J Craniomaxillofac Surg 2016; 44 (04) 347-352
• 8 Tubbs RS, Sharma A, Loukas M, Cohen-Gadol AA. Ossification of the petrosphenoidal ligament: unusual variation with the potential for abducens nerve entrapment in Dorello's canal at the skull base. Surg Radiol Anat 2014; 36 (03) 303-305
• 9 Cederberg RA, Benson BW, Nunn M, English JD. Calcification of the interclinoid and petroclinoid ligaments of sella turcica: a radiographic study of the prevalence. Orthod Craniofac Res 2003; 6 (04) 227-232
• 10 Nagaseki Y, Shimizu T, Kakizawa T, Fukamachi A, Nukui H. Primary internal ophthalmoplegia due to head injury. Acta Neurochir (Wien) 1989; 97 (3-4): 117-122
• 11 Iwanaga J, Kikuchi K, Tabuchi K. et al. A histology guide for performing human cadaveric studies: SQIP 2024 what to look for with light microscopy. Clin Anat 2024; 37 (05) 555-562
• 12 Iwanaga J, Singh V, Takeda S. et al. Standardized statement for the ethical use of human cadaveric tissues in anatomy research papers: recommendations from Anatomical Journal Editors-in-Chief. Clin Anat 2022; 35 (04) 526-528
• 13 Potu BK, Al-Khamis FH, Taher HH, Abdulreheim A. Occurrence of the ossification of petrosphenoid ligament: a retrospective radiologic study from computed tomographic images. Folia Morphol (Warsz) 2024; 83 (01) 176-181
• 14 Ambekar S, Sonig A, Nanda A. Dorello's canal and Gruber's ligament: historical perspective. J Neurol Surg B Skull Base 2012; 73 (06) 430-433
• 15 Fukushima T, Day JD, Hirahara K. Extradural total petrous apex resection with trigeminal translocation for improved exposure of the posterior cavernous sinus and petroclival region. Skull Base Surg 1996; 6 (02) 95-103
• 16 Tubbs RS, Radcliff V, Shoja MM. et al. Dorello canal revisited: an observation that potentially explains the frequency of abducens nerve injury after head injury. World Neurosurg 2012; 77 (01) 119-121
• 17 Destrieux C, Velut S, Kakou MK, Lefrancq T, Arbeille B, Santini JJ. A new concept in Dorello's canal microanatomy: the petroclival venous confluence. J Neurosurg 1997; 87 (01) 67-72
• 18 Rhoton Jr AL. The sellar region. Neurosurgery 2002; 51 (4, Suppl): S335-S374
• 19 Iwanaga J, Singh V, Ohtsuka A. et al. Acknowledging the use of human cadaveric tissues in research papers: recommendations from anatomical journal editors. Clin Anat 2021; 34 (01) 2-4