Anatomy of the Optic Canal: A Computed Tomography Study of Endoscopic Nerve Decompression

Objective (1) Analyze the radiographic anatomy of the optic canal in relationship to the sphenoid sinus. (2) Understand the role variation in optic canal anatomy may have in the variability of outcomes in optic nerve decompression. Methods Fine cut computed tomography images of the sinuses were obtained with an IRB waiver. Optic canal dimensions were measured on sinus computed tomography images of 96 patients. 191 optic canals were analyzed (111 females, 80 males). Student T-test calculations were performed for statistical analysis on computer software. Results The average medial canal wall length was 1.48 centimeters (range 0.7–2.3). The length in males was 1.61 centimeters (1.1–2.3) as compared to 1.39 centimeters (0.7–2.0) in females (p=8.0–7). The average degree of exposure of the optic canal exposed to the sphenoid sinus was 101.3 degrees (56–176). The degree of exposure was 105.6 in males versus 98.2 in females (p=.01). The potential area of canal exposed to the sphenoid sinus was 0.66 centimeters squared or 28% of the total surface area. The potential area exposed to the sphenoid sinus in males was 0.76cm2 (28%) and 0.58 centimeters squared (27%) in females. Conclusions A wide range in medial canal wall length and exposure of the bony optic canal to the sphenoid sinus exists on CT images. The variation in medial canal wall length and in optic canal exposure to the sphenoid sinus may contribute to the variability in success rates of endoscopic optic nerve decompression for optic neuropathy.

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Anatomy of the Optic Canal: A Computed Tomography Study of Endoscopic Nerve Decompression

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348940911801203 ◽

2009 ◽

Vol 118 (12) ◽

pp. 839-844 ◽

Cited By ~ 27

Author(s):

Catherine K. Hart ◽

Phillip V. Theodosopoulos ◽

Lee A. Zimmer

Keyword(s):

Computed Tomography ◽

Optic Canal ◽

Nerve Decompression

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Cone-beam computed tomography of the orbit and optic canal volumes

Journal of Cranio-Maxillofacial Surgery ◽

10.1016/j.jcms.2016.06.003 ◽

2016 ◽

Vol 44 (9) ◽

pp. 1342-1349 ◽

Cited By ~ 11

Author(s):

Reinhard E. Friedrich ◽

Marc Bruhn ◽

Christian Lohse

Keyword(s):

Computed Tomography ◽

Cone Beam Computed Tomography ◽

Cone Beam ◽

Optic Canal

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Visual Outcome of Tuberculum Sellae Meningiomas after Extradural Optic Nerve Decompression

Neurosurgery ◽

10.1227/01.neu.0000228683.79123.f9 ◽

2006 ◽

Vol 59 (3) ◽

pp. 570-576 ◽

Cited By ~ 90

Author(s):

Tiit Mathiesen ◽

Lars Kihlström

Keyword(s):

Cerebrospinal Fluid ◽

Optic Nerve ◽

Diabetes Insipidus ◽

Visual Outcome ◽

Optic Canal ◽

Visual Deterioration ◽

Nerve Decompression ◽

Visual Outcomes ◽

Tuberculum Sellae

Abstract OBJECTIVE: Meningiomas of the tuberculum sellae have a close relationship with the optic apparatus. Even modern series show a 10 to 20% risk of visual deterioration after surgery. We have attempted to improve visual outcome by extradural decompression of the optic canal and anterior clinoid process, followed by intradural release of the optic nerve; this study provides an analysis of visual outcomes with this approach. METHODS: Treatment, histopathology, and follow-up data of 29 consecutive patients undergoing surgery for tuberculum sellae meningiomas with initial release of the optic nerve were prospectively collected. RESULTS: Radical tumor removal was possible in all 23 patients with primary tumors and in three out of six patients with recurrent tumors. All patients but two of the worst affected with preoperative visual compromise improved from surgery; there were no instances of visual deterioration. Five patients with normal preoperative vision remained intact and visual improvement was 22 (91%) out of 24 patients in the remaining patients. In total, 13 patients (42%) had completely normal vision at follow-up. Mainly patients younger than 60 years experienced complete normalization after surgery. Two patients underwent transsphenoidal surgery for cerebrospinal fluid leaks. Postoperative endocrinological symptoms were temporary diabetes insipidus in one patient and permanent diabetes insipidus in another patient undergoing elective sectioning of the pituitary stalk because of a recurrent tumor with invasive growth into the stalk. CONCLUSION: Adding early optic nerve decompression by extradural clinoidectomy and optic canal unroofing to a frontopterional approach seemed to improve visual outcomes because there were no instances of visual deterioration. Simpson Grade 1 to 2 removal was possible in all patients with primary surgery, whereas recurrent cases could only be treated with lower grades of radicality. Radical removal, however, required readiness to reoperate for cerebrospinal fluid leakage at the site of the drilled tumor origin in bone.

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Relation between optic and carotid canals with sphenoid sinus in patients with communicant hydrocephalus: a computed tomography evaluation study

Acta Radiologica ◽

10.1177/0284185119895483 ◽

2020 ◽

Vol 61 (8) ◽

pp. 1064-1071

Author(s):

Ziya Şencan ◽

Nuray Bayar Muluk ◽

Yunus Yilmazsoy ◽

Adnan Özdemir ◽

Havva Meltem Mutlucan

Keyword(s):

Computed Tomography ◽

Sphenoid Sinus ◽

Optic Canal ◽

Cranial Computed Tomography ◽

Control Group ◽

Group Type ◽

Carotid Canal ◽

Adjacent Structures ◽

Positive Correlations ◽

Type 3

Background There are neuro-ophthalmologic findings in patients with communicant hydrocephalus (CH). Purpose To investigate the relationships of the optic canal and carotid canal classifications at sphenoid sinus and anterior clinoid process (ACP) pneumatization in patients with CH. Material and Methods In this multicentric retrospective cross-sectional study, the cranial computed tomography (CT) images of 38 patients with CH (20 men, 18 women) and 40 controls (25 men, 15 women) were included. Optic and carotid canal classification at sphenoid sinus, ACP pneumatization, and sphenoid sinus septation were evaluated. Results In the CH group, type 3 optic canal was detected in 21.1% of the patients and type 4 optic canal was detected in 2.6% of the patients on the left side which was significantly different from the control group ( P<0.05). In the CH group, type 3 carotid canal was detected in 21.1% of the patients (left) and 18.4% of the patients (right). ACP pneumatization was present in 13.2% of the patients in the CH group bilaterally. There were positive correlations between optic canal classifications and ACP pneumatization ( P<0.05). There were also positive correlations between the right and left carotid canal classifications and ACP pneumatization ( P<0.05). Conclusion To avoid complications, CT should be evaluated carefully in patients with CH before surgical interventions in sphenoid sinuses and surgeons should work carefully in the sphenoid sinus or adjacent structures. The protrusion possibility of the optic canal or carotid canal to the sphenoid sinus may be higher in pneumatized ACP patients.

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Anatomy of the posterior and middle ethmoidal arteries via computed tomography

SAGE Open Medicine ◽

10.1177/2050312118772473 ◽

2018 ◽

Vol 6 ◽

pp. 205031211877247 ◽

Cited By ~ 2

Author(s):

Hiroki Yamamoto ◽

Kazuhiro Nomura ◽

Hiroshi Hidaka ◽

Yukio Katori ◽

Naohiro Yoshida

Keyword(s):

Computed Tomography ◽

Skull Base ◽

Cell Walls ◽

Older Age ◽

Optic Canal ◽

First Wall ◽

Computed Tomography Images ◽

Ethmoidal Artery ◽

Ethmoidal Arteries ◽

Age And Sex

Objective: The aim of this study is to investigate the anatomy of the posterior and middle ethmoidal arteries from the viewpoint of an endoscopic sinus surgeon. Methods: Based on 100 computed tomography images, the anatomical position of the posterior ethmoidal artery in relation to the posterior ethmoid cells was classified into five types. The presence of the posterior and middle ethmoidal arteries, their distance from the skull base, and their length exposed in the ethmoid cells were measured. The association of patients’ age and sex, presence of the middle ethmoidal artery, and anatomical type of the posterior ethmoidal artery with the posterior ethmoidal artery distance from the ethmoid roof was analyzed. Results: The posterior ethmoidal artery’s position, relative to the ethmoid cell walls, was most often near the first wall, anterior to the optic canal (92.5%). The posterior ethmoidal artery’s distance from the skull base ranged from 0 to 6.4 mm (mean: 1.2 mm). Older age, longer length of the posterior ethmoidal artery exposed in the ethmoid cells, and absence of the middle ethmoidal artery were positively associated with a longer posterior ethmoidal artery distance from the skull base. Conclusion: Attention should be paid to the posterior and middle ethmoidal arteries.

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Evaluation of Optic Canal and Surrounding Structures Using Cone Beam Computed Tomography

Journal of Craniofacial Surgery ◽

10.1097/scs.0000000000002726 ◽

2016 ◽

Vol 27 (5) ◽

pp. 1327-1330 ◽

Cited By ~ 6

Author(s):

Alper Sinanoglu ◽

Kaan Orhan ◽

Sebnem Kursun ◽

Beste Inceoglu ◽

Bengi Oztas

Keyword(s):

Computed Tomography ◽

Cone Beam Computed Tomography ◽

Cone Beam ◽

Optic Canal

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Ultra-Early Optic Nerve Decompression for the Resection of Anterior Clinoidal Meningioma

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0038-1623521 ◽

2018 ◽

Vol 79 (S 02) ◽

pp. S231-S232

Author(s):

Soichi Oya ◽

Toru Matsui

Keyword(s):

Optic Nerve ◽

Surgical Resection ◽

Surgical Techniques ◽

Magnetic Resonance Images ◽

Optic Canal ◽

Decompression Surgery ◽

Nerve Decompression ◽

Visual Deficits ◽

Optic Nerve Decompression ◽

The Right

AbstractImprovement in vision is one of the main goals of surgery for anterior clinoidal meningiomas with visual deficits. Early optic nerve decompression surgery has been advocated in previous studies to achieve the best visual outcome. Through this video, the authors describe their surgical techniques to decompress the optic nerve at the very early stage of surgery. A 35-year-old patient presented with subjective blurry vision in the right eye over the last 8 months. Magnetic resonance images showed a 3.2-cm meningioma arising at the right anterior clinoid. Preoperative ophthalmological test was within the normal range, but the patient wished to have surgical resection after a detailed discussion of benefits and risks related to surgical resection. The surgical strategy consisted of the right lateral subfrontal approach that includes a standard right frontotemporal craniotomy, extradural anterior clinoidectomy, and early optic nerve decompression prior to tumor resection. The tumor was divided into compartments defined by the arteries and resected. Simpson grade II resection was achieved without complications. The patient's symptoms disappeared. In anterior clinoidal meningiomas that cause visual deficits, the optic nerve is assumed very vulnerable to any further injuries related to the operative maneuver. Ultra-early optic nerve decompression can be performed in anterior clinoidal meningiomas regardless of their size by extradural unroofing of the optic canal and sectioning of the optic canal sheath, which we believe contributes to better visual improvement.The link to the video can be found at: https://youtu.be/RIFi4ecWAhQ.

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Extradural Anterior Clinoidectomy as an Alternative Approach for Optic Nerve Decompression: Anatomic Study and Clinical Experience

Operative Neurosurgery ◽

10.1227/01.neu.0000236122.28434.13 ◽

2006 ◽

Vol 59 (suppl_4) ◽

pp. ONS-253-ONS-262 ◽

Cited By ~ 4

Author(s):

Yang Yang ◽

Hongjie Wang ◽

Yi Shao ◽

Zenghua Wei ◽

Shugan Zhu ◽

...

Keyword(s):

Optic Nerve ◽

Optic Neuropathy ◽

Optic Canal ◽

Falciform Ligament ◽

Traumatic Optic Neuropathy ◽

Pterional Craniotomy ◽

Anterior Clinoidectomy ◽

Nerve Decompression ◽

Optic Nerve Decompression ◽

Alternative Approach

Abstract OBJECTIVE: We introduce pterional craniotomy extradural anterior clinoidectomy as a new alternative approach for optic nerve decompression in patients with traumatic optic neuropathy. METHODS: Intracranial structures pertinent to pterional craniotomy extradural anterior clinoidectomy were carefully studied in 10 dry craniums and 10 cranial bases with dura mater. Important parameters of these structures were measured. Stepwise dissections simulating pterional craniotomy extradural anterior clinoidectomy were performed in 20 cadaver heads bilaterally. Pterional craniotomy extradural anterior clinoidectomy was then applied to 12 patients (13 eyes) with traumatic optic neuropathy and severe visual dysfunction. RESULTS: The anatomic features and their variations of optic canal, ophthalmic artery, falciform ligament, and Zinn's ring (annular tendon) were studied and measured in detail. Extensive opening of the optic canal and optic nerve sheath was successfully achieved in all 12 patients without major surgical complications. Significant visual acuity improvement occurred in eight (nine eyes) out of our 12 patients after surgery. The surgical techniques and advantages of pterional craniotomy extradural anterior clinoidectomy for optic nerve decompression are presented and discussed in detail. @@CONCLUSION:@@ Pterional craniotomy extradural anterior clinoidectomy is a promising new alternative approach for optic nerve decompression in patients with traumatic optic neuropathy.

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