The Dorello Canal

Historical Development, Controversies in Microsurgical Anatomy, and Clinical Implications

Varun R. Kshettry, M.D; Joung H. Lee, M.D; Mario Ammirati M.D., M.B.A

Neurosurg Focus. 2013;34(3):e4

Conclusions

The anatomy of the abducent nerve in the petroclival region helps explain abducent palsies seen in clinical practice. Knowledge of the relationships between bony landmarks, venous sinus anatomy, and cranial nerves is critical for safe surgery in this area. Additionally, familiarity with anatomical variations enhances surgical knowledge.

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Author contributions to the study and manuscript preparation include the following. Conception and design: Kshettry. Acquisition of data: Kshettry. Analysis and interpretation of data: Kshettry. Drafting the article: Kshettry. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Ammirati. Statistical analysis: Kshettry. Administrative/technical/material support: Lee. Study supervision: Ammirati.

Acknowledgements
The authors greatly appreciate Mark Sabo, B.F.A., and the Medical Art Department at the Cleveland Clinic for the development of the graphics for the manuscript.

Abbreviations used in this paper
DMA = dorsal meningeal artery; ICA = internal carotid artery; IPS = inferior petrosal sinus; PVC = petroclival venous confluence.

Table 1. Review of studies detailing microsurgical anatomy of the Dorello canal and the abducent nerve
Authors & Year	Specimens	Definition	Canal Dimensions (mm)	Gruber Ligament	Abducent Course	Vasculature
Umansky et al., 1991	20	classic	diameter 0.5–3.0 (mean 1.5), length 4.0–13 (mean 9.2)	butterfly shape, silver color, mean length 12.3 ± 2.2 mm; duplicated 5%, ossified 5%, hypoplastic 5%	inside Dorello canal 100%; location in canal: medial 9%, middle 52%, lat 39%; duplicated nerve 15%	DMA present in canal in 80%; ostium of IPS outside canal in 100%; relation to abducent: 20% medial, 80% lat
Tsitsopoulos et al., 1996	20	classic	diameter 6–10 (mean 7.5), length 2.5–6 (mean 3.88)	butterfly shape, length 8–16 mm (mean 11.5 mm); duplicated 15%, ossified 10%, hypoplastic 10%	inside Dorello canal 100%; location in canal: medial 0%, middle 15%, lat 85%	DMA inside canal 75%; ostium of IPS outside canal 100%; relation to abducent: 15% medial, 85% lat
Destrieux et al., 1997	28	PVC	not given	butterfly shape; ossified 4%, hypoplastic 4%	abducent w/in PVC 100%; 96% below & 4% above Gruber ligament; abducent duplication 7%	ostium of IPS outside PVC 100%
Ozveren et al., 2002	8	PVC	not given	butterfly shape, smaller toward petrous apex	abducent w/in PVC 100%, below Gruber ligament 100%; location in canal: medial 0%, middle 25%, lat 75%	abducent nerve supplied by tiny arteries traveling inside subarachnoid space from cisternal segment
Iaconetta et al., 2003	40	PVC	classic definition: canal mean length 8.4, mean height 1.7	butterfly shape, silver color, mean length 13.3 ± 2.3 mm; ossified 7.5%, hypoplastic 2.5%	venous segment of abducent mean length 11.5 ± 3.7 mm	DMA under Gruber ligament 85%; ostium of IPS relation to abducent: medial 40%, lat 60%
Ozveren et al., 2007	10	not specified	length from dural porus to lat wall of cavernous ICA 8.5–11 (mean 9.5)	not given	abducent below Gruber ligament 100%	lat clival artery supplies abducent dural sheath, but not nerve (confirmed on histology)
Iaconetta et al., 2007	100	classic	not given	butterfly shape, mean length 13.3 ± 2.3 mm; ossified 6%, hypoplastic 3%, histological continuity w/petrolingual ligament (falciform)	abducent gulfar segment length 11.5 ± 1.7 mm, abducent duplicated 8%	DMA under Gruber ligament in 86%

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The Dorello Canal

Historical Development, Controversies in Microsurgical Anatomy, and Clinical Implications

Conclusions

Tables

References

Authors and Disclosures

Authors and Disclosures

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