Optic Canal Research Articles

Mapping the Posterior Ledge and Optic Foramen in Orbital Floor Blowout Fractures.

Background The posterior ledge (PL) is a vital structure that supports the implant posteriorly during orbital floor reconstruction. This study describes a technique for mapping the PL in relation to the infraorbital margin (IM) in patients with orbital floor blowout fractures. This study establishes the location of the optic foramen in relation to the PL. Methods Facial computed tomography (FCT) scans of 67 consecutive patients with isolated orbital floor blowout fractures were analyzed using Osirix. Planes of reference for orbital fractures, a standardized technique for performing measurements on FCT, was used. Viewed coronally, the orbit was divided into seven equal sagittal slices (L1 laterally to L7 medially) with reference to the midorbital plane. The distances of PL from IM and location of optic foramen were determined. Results The greatest distance to PL is found at L5 (median: 30.1 mm, range: 13.5-37.1 mm). The median and ranges for each slice are as follows: L1 (median: 0.0 mm, range: 0.0-19.9 mm), L2 (median: 0.0 mm, range: 0.0-21.5 mm), L3 (median: 15.8 mm, range: 0.0-31.7 mm), L4 (median: 26.1 mm, range: 0.0-34.0 mm), L5 (median: 30.1 mm, range: 13.5-37.1 mm), L6 (median: 29.0 mm, range: 0.0-36.3 mm), L7 (median: 20.8 mm, range: 0.0-39.2 mm). The median distance of the optic foramen from IM is 43.7 mm (range: 37.0- 49.1) at L7. Conclusion Distance to PL from IM increases medially until the L5 before decreasing. A reference map of the PL in relation to the IM and optic foramen is generated. The optic foramen is located in close proximity to the PL at the medial orbital floor. This aids in preoperative planning and intraoperative dissection.

Scanning Laser Ophthalmoscopy Demonstrates Disc and Peripapillary Strain During Horizontal Eye Rotation in Adults

We used automated image analysis of scanning laser ophthalmoscopy (SLO) to investigate mechanical strains imposed on disc, and retinal and choroidal vessels during horizontal duction in adults. Deep learning analysis of optical images. The peripapillary region was imaged by SLO in central gaze, and 35° abduction and adduction, in younger and older healthy adults. Automated image registration was followed by deep learning-based optical flow analysis to track determine local tissue deformations quantified as horizontal, vertical, and shear strain maps relative to central gaze. Choroidal vessel displacements were observed when fundus pigment was light. Strains in the retina and disc could be quantified in 22 younger (mean ± SEM, 26 ± 5 years) and 19 older (64 ± 10 years) healthy volunteers. Strains were predominantly horizontal and greater for adduction than for abduction. During adduction, maximum horizontal strain was tensile in the nasal hemi-disc, and declined progressively with distance from it. Strain in the temporal hemi-retina during adduction was minimal, except for compressive strain on the disc of older subjects. In abduction, horizontal strains were less and largely confined to the disc, greater in older subjects, and generally tensile. Vertical and shear strains were small. Nasal to the disc, choroidal vessels shifted nasally relative to overlying peripapillary retinal vessels. Strain analysis during horizontal duction suggests that the optic nerve displaces the optic canal, choroid, and peripapillary sclera relative to the overlying disc and retina. This peripapillary shearing of the optic nerve relative to the choroid and sclera may be a driver of disc tilting and peripapillary atrophy.

NUT-CARCINOMA INVOLVING TRIGEMINAL NERVE - A CASE REPORT

NUT-carcinoma is a rare aggressive disease caused by BRD4/3‐NUT fusion that results in MYC upregulation. A 50-years-old male patient presented frontotemporal headache and paraesthesia, evolving with worsening headache, diplopia, ptosis and reduced visual acuity for at least 12 months. Clinical diagnosis was meningioma due to an expansive process in the right temporal fossa with hyperostosis and optic canal stenosis. Histological analysis revealed malignant neoplasm presenting cohesive blocks of basaloid cells with foci of abrupt keratinization and necrosis, with infiltration of dense connective tissue and bone marrow. Immunohistochemistry was positive for EMA, P63, INI1(retained), AE1/AE3, CK5/6, CK8-18, CD117 and NUT. In addition, Ki-67 was positive in 80% of the neoplasia. Therefore, the final diagnosis was NUT carcinoma. The patient is still alive at the last follow-up. This case highlights the importance of considering NUT-carcinoma in the provisional diagnosis for undifferentiated or poorly differentiated neoplasms and immunohistochemistry can aid diagnosis. NUT-carcinoma is a rare aggressive disease caused by BRD4/3‐NUT fusion that results in MYC upregulation. A 50-years-old male patient presented frontotemporal headache and paraesthesia, evolving with worsening headache, diplopia, ptosis and reduced visual acuity for at least 12 months. Clinical diagnosis was meningioma due to an expansive process in the right temporal fossa with hyperostosis and optic canal stenosis. Histological analysis revealed malignant neoplasm presenting cohesive blocks of basaloid cells with foci of abrupt keratinization and necrosis, with infiltration of dense connective tissue and bone marrow. Immunohistochemistry was positive for EMA, P63, INI1(retained), AE1/AE3, CK5/6, CK8-18, CD117 and NUT. In addition, Ki-67 was positive in 80% of the neoplasia. Therefore, the final diagnosis was NUT carcinoma. The patient is still alive at the last follow-up. This case highlights the importance of considering NUT-carcinoma in the provisional diagnosis for undifferentiated or poorly differentiated neoplasms and immunohistochemistry can aid diagnosis.

Sinonasal Anatomy Variations on CT Scans of a Sample of Filipino Adults With Chronic Rhinosinusitis

ABSTRACT
 Objective: To determine the prevalence of sinonasal anatomic variations seen on paranasal sinus (PNS) CT scans of a sample of Filipino adults with chronic rhinosinusitis.Methods: Design: Cross-sectional study Setting: Tertiary Government Training Hospital Participants: The PNS CT scans of 51 Filipino patients with chronic rhinosinusitis with and without nasal polyposis diagnosed at our outpatien Department of Otorhinolaryngology-Head and Neck Surgery between October 2015 to December 2020 were reviewed for the presence of sinonasal anatomic variants. The prevalence of the identified variants was calculated.
 Results: The CT scans of 51 patients, 41 (80.4%) men and 10 (19.6%) women, were included. The median age was 48 years (Q25: 35, Q75: 56, IQR:21). The median Lund Mackay Score (LMS) was 15 (Q25: 12, Q75: 20, IQR:8). Majority (94%) had an LMS of ≥5. The most common anatomic variant in the study population was agger nasi (n=46/51, 90.2% present bilaterally) followed by uncinate process attachment to the lamina papyracea (n=90/102, 88.24%). The third to sixth most common findings were Keros type II classification (n=76/102, 74.51%), nasal septal deviation (n=35/51, 68.62%), optic nerve canal type 1 (n=67/102, 65.69%) and anterior ethmoid artery grade 1 (n=46/102, 45.1%), respectively. Less common variants were Onodi cell (n=13/51, 25.49% unilateral and n=10/51, 19.61% bilateral), Haller cell (n=8/51, 15.69% unilateral and n=1/51, 1.96% bilateral), supraorbital cell (n=4/51, 7.84% unilateral and n=4/51, 7.84% bilateral), middle turbinate concha bullosa (n=3/51, 5.88% unilateral and n=6/51, 11.76% bilateral), superior turbinate concha bullosa (n=2/51, 3.92% unilateral and n=1/51, 1.96% bilateral), pneumatized crista galli (n=2/51, 3.92%) and optic nerve dehiscence (n=1/51, 1.96% bilateral). 
 Conclusion: In the adult Filipino population with CRS sampled in this study, the six most common sinonasal anatomic variants were agger nasi, superior attachment of the uncinate process to the lamina papyracea, Keros type II classification, septal deviation, optic nerve canal type 1 and anterior ethmoid artery grade 1. Pre-operatively, the PNS CT scan of every patient must be meticulously evaluated for the sinonasal anatomic variants to avoid surgical complications.

Ophthalmic artery arising from the external carotid artery system: the middle meningeal artery in South African patients

BackgroundThe ophthalmic artery is the first branch of the internal carotid artery. It arises from the supraclinoid segment of the internal carotid artery within the subarachnoid space and enters the orbit via the optic canal. However, due to complex embryogenesis, the ophthalmic artery can arise from different parts of the internal carotid artery or the distal branches of the external carotid artery. This is usually associated with a variation in the course of the ophthalmic artery through the superior orbital fissure instead of coursing through the optic canal. The ophthalmic artery and its branches vascularise the eyeball and its contents. Consequently, information about its morphologic variation is essential for treating clinical conditions such as central retinal artery occlusion, retinoblastoma chemoembolization, and ophthalmic artery aneurysm.Case presentationWe report on two cases of the ophthalmic artery arising from the middle meningeal artery in one adult (33-year-old Indian female) and one pediatric (2-year-old African male) South African patient examined by digital subtraction angiography. The patients were diagnosed with arteriovenous malformations and bilateral retinoblastoma, respectively.ConclusionsThe ophthalmic artery plays a vital role in vision generation. Thus, its anatomy is of clinical interest to neurosurgeons, ophthalmologists, and interventional radiologists.

Suprasellar Meningioma Classification: Endoscopic Transnasal Perspective.

Objectives Midline suprasellar meningiomas include planum sphenoidale, tuberculum sellae, and diaphragma sellae meningiomas. Multiple classifications have been previously documented; however, they come with controversies and limitations, including those with surgical implications. The aim of this study was to classify suprasellar meningiomas based on their behavior toward the underlying bone and neurovascular structures. Methods Patients with newly diagnosed suprasellar meningiomas that underwent extended endoscopic transnasal approach between 2015 and 2021 were included in this study. The following parameters were evaluated: chiasmatic sulcus length, location of the optic chiasm and nerves, optic canal involvement, and vascular displacement. Results We identified 40 cases of midline suprasellar meningiomas, 1 diaphragma sellae meningioma (type A), 10 tuberculum sellae meningiomas (type B), 9 chiasmatic sulcus meningiomas (type C), and 10 planum sphenoidale meningiomas (type D). Asymmetrical visual complaints were most common in chiasmatic sulcus meningiomas, followed by tuberculum sellae meningiomas (66 and 50%, respectively). Chiasmatic sulcus meningiomas showed increased separation between the optic chiasm and the A1/A2 complex (8.9 mm) compared with tuberculum sellae (2.7 mm) and planum sphenoidale (1.9 mm) meningiomas. Compared with other types, increased chiasmatic sulcus length was observed in chiasmatic sulcus meningiomas. Conclusion Preoperative evaluation of bone involvement and tumor relation to neurovascular structures can be used to classify suprasellar meningiomas. Chiasmatic sulcus meningioma is a distinct subtype of suprasellar meningiomas. Its unique behavior toward nearby neurovascular structures could be of surgical value during tumor resection.

Comparative characteristics of extended endoscopic endonasal operations in giant pituitary adenomas with ventricular system extention and craniopharyngiomas

Objective ‒ to evaluate the results of extended endonasal interventions in patients with craniopharyngioma (CPH) and giant pituitary adenoma (GPA) with an extension to ventricular system, to compare the effects of interventions in these pathologies, to determine the basic principles of extended endoscopic endonasal surgical interventions. Materials and methods. The study is based on a retrospective analysis of patients endoscopically operated through the nose in the Department of Endonasal Neurosurgery of the Skull base in the SI «Romodanov Neurosurgery Institute NAMS of Ukraine» from 2014 to 2021. In the group with GPA were 18 (36.7 %) female and 31 (63.3 %) male patients. The mean age of the patients was 54.1±11.3 years. The CPH group included 42 (60.9 %) women and 27 (39.1 %) men. The mean age in this group was 46.6±14.5 years. Results. In 14.3 % of GPA cases, postoperative cerebrospinal fluid leak (CSFL) occurred, which is statistically insignificant compared to the postoperative CSFL level at CPH – 13 %, despite the fact that when removing GPA, we routinely encountered high-flow liquorrhea, given the characteristics of tumor growth (p=0.921). The number of electrolyte abnormalities with CPH was higher than with GPA removal (40.5 % with CPH versus 16.3 % with GPA). For the first time, diabetes insipidus requiring the prescription of hormone replacement therapy due to the removal of GPA that were extending to the ventricular system was diagnosed in the postoperative period in 12.2 % of patients versus 33.3 % in CPH group. Endocrine disorders in the form of hypopituitarism were found in 34.7 % of GPA and 44.9 % of CPH. The median duration of the operation was 227.9±74.9 min for GPA and 318.4±65.4 min for CPH. The area of the trepanation window is always larger in GPA, as it includes an enlarged sellar window and, sometimes, a parasellar direction in the invasion of the cavernous sinuses. Decompression of the optic canals was performed almost exclusively in GPA that extend parasellarly and/or retrosellarly (38,0 % with CPH in comparison to 5.8 % in the GPA group). Closure of the skull base defect was performed with autologous and artificial materials in all cases, as the removal of GPA and CРН was always accompanied by high-flow intraoperative CSFL.Conclusions. After analyzing the results of endonasal surgeries performed in GPA with extension to the ventricular system and CPH, it was noted that the use of extended transtuberculum-transplanum approach provides a wide surgical corridor and provides the possibility of total tumor removal. It is essential to install a lumbar drainage system when working in open liquid spaces. In our opinion, the priority should be given to the safety of operations and prevention of postoperative interventions (preservation of the pituitary stem, perforating arteries, chiasm, minimization of manipulations with the diencephalic areas and the bottom of the III ventricle), rather than increasing radicality in CPH, as in GPA. Fatty graft packaging should be avoided for CPH located near the junction of the optic nerves (in the anterior position of the chiasm), as the absence of the arachnoid barrier increases the risk of involving the optic structures in the postoperative scar.

Long-term Outcomes Following Endoscopic Transnasal Surgery for Optic Neuropathy Due to Craniofacial Fibrous Dysplasia.

To investigate the feasibility of endoscopic transnasal optic canal decompression (ETOCD) guided by a navigation surgical system (NSS) for vision recovery in patients with compressive optic neuropathy (CON) caused by craniofacial fibrous dysplasia (CFD), and to explore the underlying cause of visual impairment. All patients underwent unilateral NSS-guided ETOCD and were followed up periodically for at least six months. Paired sample t-test and Pearson correlation analyses were used to compare continuous variables of the visual outcomes at the final review. A histopathological test of abnormal bone specimens was performed postoperatively. Thirty-four patients were finally included, and all surgeries were uneventful. The best corrected visual acuity (BCVA) (logMAR units) decreased from 1.29 ± 0.80 preoperatively to 0.97 ± 0.78 at the last follow-up (p = 0.0012), improving in 28 patients (82.35%). The absolute value of mean defect (MD) significantly decreased (p < 0.001). Color vision was impaired in 17 patients preoperatively and improved in 6 patients. BCVA at the last follow-up was significantly correlated with preoperative BCVA, onset time, preoperative retinal nerve fibril layer thickness, and MD (all p < 0.05). Among 34 patients, 26 had a blunt bony process near the anterior foot of the optic chiasm. Of the total patients, 73.53% patients experienced bony fiber recurrence 6 months or earlier after surgery without visual loss. NSS-guided ETOCD appeared to be safe and effective for visual recovery in patients with CON due to CFD, and early surgical intervention was critical for long-term recovery. Unbalanced compression of the optic canal by the blunt bony process may be a major cause of visual impairment. 4 Laryngoscope, 133:1857-1866, 2023.

Diagnosis and treatment of transnasal endoscopic optic canal decompression for traumatic optic neuropathy.

To investigate the clinical efficacy and prognostic factors of transnasal endoscopic optic decompression in the treatment of traumatic optic neuropathy (TON). A retrospective analysis was performed on 13 TON patients in The Seventh Affiliated Hospital of Sun Yat-sen University and Shenzhen Eye Hospital in Shenzhen City (China) from June 2020 to April 2022. These patients had received transnasal endoscopic optic decompression, and hormonal and neurotrophic drugs were given after surgery. Visual acuity (VA) improvement was used as the criterion to judge clinical efficacy. In a total of 13 patients, 13 injured eyes (12 men and 1 woman; mean age, 28.0 ± 11.8 years) received transnasal endoscopic optic decompression. After surgery, nine patients had improved VA, whereas four patients failed to show any improvement, resulting in a total effective rate of 69.2%. Of the six patients with no light perception preoperatively, three had effective results after the operation, giving an effective rate of 50.0%. Of the seven patients with residual light sensation preoperatively, six had effective results after the operation, giving an effective rate of 85.7%. Of the 10 patients operated on within 7 days after injury, seven had effective results, giving an effective rate of 70%. Of the three patients injured and operated on after 7 days, two had effective results, giving an effective rate of 66.7%. Transnasal endoscopic optic nerve decompression is an effective treatment method for TON. The presence of residual light perception and the timing of surgery within 7 days are crucial to the prognosis.

Endoscopic endonasal optic nerve sheath decompression (EONSD) for idiopathic intracranial hypertension: Technical details and meta-analysis

BackgroundThe neurosurgical management of idiopathic intracranial hypertension (IIH) remains controversial. Although shunting and newer endovascular stenting techniques are part of the neurosurgical armamentarium to treat medically refractory IIH symptoms, optic nerve sheath fenestration has traditionally been performed by ophthalmologists. ObjectiveWe present a detailed cadaveric dissection that simulates the endoscopic endonasal optic nerve sheath decompression (EONSD) technique along with the literature review. MethodsEONSD was performed in four freshly injected cadaveric specimens. Additionally, a systematic review from different electronic databases has been done. ResultsBilateral EONSD was performed in all specimens without significant technical difficulties. Based on our experience, there is no need to expose the periorbita or orbital apex. The primary anatomic landmarks were the optic canal, the lateral opticocarotid recess, the tuberculum, the limbus, and the clinoid segment of the internal carotid artery. Based on the systematic review, 68 patients (77.9% female) underwent EONSD, with a mean age of 33.4 ± 6.9 years in adult patients. Follow-up ranged from 3 to 58 months across different studies. The pooled meta-analysis showed headache, papilledema, and visual disturbance improvement in 78% [95%CI 0.65–0.90], 72% [95%CI 0.61–0.83], and 88% [95%CI 0.80–0.96] of cases who underwent EONSD, respectively. The subgroup analysis showed there was no statistically significant difference between unilateral and bilateral EONSD in terms of different measured outcomes. ConclusionEONSD is a feasible surgical procedure that may obviate the need for shunting in patients with IIH. Although clinical studies showed that EONSD is a safe and effective technique, further studies are required to establish the preferences of either unilateral or bilateral approaches.

Strabismus and Exophthalmos in Children: Think of Optic Nerve Glioma

Introduction: Optic nerve gliomas are rare tumors that are mainly observed in children. Exophthalmos and strabismus are the main signs of the disease. Neuroimaging and in particular magnetic resonance imaging is of great help in the diagnosis and follow-up of these tumors. The therapeutic management of these gliomas involves different means: surgical removal, chemotherapy, radiotherapy or abstention under surveillance. The indications must be discussed on a case-by-case basis. We report in this work a case of optic nerve glioma revealed by a strabismus and a unilateral exophthalmos. Case Report: This is a 3-year-old girl from a non-consanguineous marriage, with no specific pathological ATCD, who presented with divergent strabismus with left exophthalmos evolving for 3 months. The ophthalmologic examination noted a constant wide-angle divergent strabismus on the left eye with moderate exophthalmos on the same side. Corrected visual acuity was reduced to near finger count on the left and 5/10 on the right. Somatic examination found café au lait spots on the back and trunk. Cerebral CT showed a bilateral thickening of the optic nerves, fusiform and regular, more marked on the left, isodense to spontaneous contrast, homogeneously enhancing after injection of PDC. On the left, it is responsible for a downward refoulement of the eyeball with grade 1 exophthalmos. An MRI was ordered revealing a regular well-limited fusiform thickening of the optic nerves in T1 isosignal, intermediate in T2 and FLAIR, in diffusion hypersignal without ADC restriction, intensely and finely heterogeneous enhancing after injection of contrast medium. This thickening is responsible for a grade I left exophthalmos, with widening of the optic canals posteriorly and filling of the intraconical fat evoking a glioma appearance. The child was referred to neurosurgery for management. Conclusion: The diagnosis of optic nerve glioma in children is rare, with atypical presentations both in terms .........

Anatomical Study and Clinical Application of Optic Canal Decompression Via Transethmoid-sphenoid Approach Under Endoscope.

This study aimed to evaluate the safety and accuracy of the endoscopic transethmoid-sphenoid approach for optic canal decompression. Twelve sides of 6 adult cadaveric heads fixed in formalin were selected to simulate optic canal decompression using the endoscopic transethmoid-sphenoid approach. Furthermore, this approach was used for optic canal decompression in 10 patients (11 eyes) with optic nerve canal injury. Related anatomical structures were observed using a 0-degree endoscope, and the anatomical characteristics as well as the surgical data were collected. The maximum effective widths of the cranial opening, orbital opening, and middle segment of the canal that could be drilled open endoscopically were 7.82±2.63, 8.05±2.77, and 6.92±2.01mm, respectively. The angle between the line linking the center point of the tubercular recess with the midpoint of the cranial opening of the optic canal and the horizontal coordinate was 17.23±1.34 degrees. At the orbital opening of the optic canal, the ophthalmic artery was located directly inferior to the optic nerve in 2 cases (16.7%) and laterally inferior to the optic nerve in 10 cases (83.3%). Six of the operational eyes were effective while the remaining 5 were ineffective. No postoperative complications such as bleeding, infection, or cerebrospinal fluid leakage were observed during the follow-up period (6-12mo). In conclusion, optic canal decompression positively impacts the prognosis of partial traumatic optic neuropathy. Furthermore, the endoscopic transethmoid-sphenoid approach for optic canal decompression is a minimally invasive procedure that provides direct access and adequate decompression. This technique is easy to master and suitable for clinical applications.

Anatomical Variations of the Optic Nerve in the Sphenoid Sinus: Do Ethnic Variations Matter?

There are several variations in the anatomical relations of the optic nerve with the sphenoid sinus. Proper understanding of these variations is clinically important to minimize injuries associated with surgical procedures that involve the sphenoid sinus. CT scans of paranasal sinuses obtained prior to any endoscopic surgery in the sphenoid sinus area is useful for designing operative strategies. Ethnic variations in sinonasal anatomy have been documented. The objective was to study the pattern of relationship between optic nerve and the sphenoid sinus using computerized tomographic imaging in a north Indian population, to compare our findings with previous studies in different ethnic groups and find out if ethnic variations in such a relationship matter. A prospective study was conducted on 300 patients who underwent computed tomography of the paranasal sinuses from Sept 2020 to June 2021. Relationship of optic nerves to the sphenoid sinuses was categorized according to DeLano classification. Pneumatization of the anterior clinoid process and bony dehiscence of optic nerve was also observed. Type 1 position of optic nerve was seen in 69.3%, Type 2 in 20.9%, Type 3 in 3% and Type 4 in 6.8% of sinuses. The pneumatization of anterior clinoid process (ACP) was observed in 10.5% and the bony dehiscence of optic nerve was noted in 6.5% sinuses. Bony dehiscence of optic canal had associated ACP pneumatization in 64.1% sinuses.The variability of the relation of optic nerve to the sphenoid sinus even in the persons of same ethnicity precludes a definite role of ethnicity in these variations. Other factors possibly contributing to such a relationship have been discussed.

Endoscopy-Assisted Microneurosurgery for Sella and Optic Foramen Invading Anterior Cranial Fossa Base Meningiomas

Anterior skull base meningioma produces symptoms as a result of mass effect and neurovascular compression. The bony anatomy of the anterior skull base is complex and houses the critical cranial nerves and vessels. Traditional microscopic approaches remove these tumors effectively but require extensive brain retraction and bone drilling. Endoscope assistance offers the advantages of a smaller incision, less brain retraction, and bone drilling. The most significant advantage of endoscope-assisted microneurosurgery for lesions invading the sella and optic foramen is the complete resection of the sellar and foraminal components frequently responsible for recurrence. In this report, we describe the technique of endoscope-assisted microneurosurgical resection of anterior skull base meningiomas invading the sella and foramen. We present 10 cases and 3 case examples of endoscope-assisted microneurosurgery for meningiomas invading the sella and optic foramen. This report presents the operating room setup and surgical details to resect sellar and foraminal tumors. The surgical procedure is presented as a video. Endoscope-assisted microneurosurgery yielded excellent clinical and radiologic results and no recurrence at the last follow-up of meningiomas invading the sella and optic foramen. The present article discusses the challenges faced with endoscope-assisted microneurosurgery, techniques, and challenges in the procedure. Endoscope assistance enables complete tumor excision under vision with less retraction and bone drilling in anterior cranial fossa meningioma, invading the chiasmatic sulcus, optic foramen, and sella. The mixed use of microscope and endoscope makes it safer and saves time and is like bringing out the best of both worlds.

Identification of orbital arteries by means of stamp-pad ink on embalmed cadavers

Vascular identification is an effective way of analysing the vascular system from large to very small blood vessels in cadaveric studies. A variety of vascular injection products have been utilised over the past decades to facilitate and demonstrate dissection of the blood vessels. The coloured dye used to demonstrate the branching patterns of the vascular system was introduced by Jean Riolan (1580 to 1657) (Doomernik et al., 2016). Although different identification techniques are available, only a few can be used on the specimens during dissections. A total of 118 human eyes from 59 bodies were dissected and all blood vessels were exposed. The ophthalmic artery (OA) and its branches were identified by means of fine dissections. The aid of a lighted magnifying glass made fine dissections of small blood vessels possible. After removing the orbital fat around the blood vessels, the arteries were then smoothly painted with the red stamp-pad ink and a paintbrush. Specimens were then allowed to dry at room temperature before photographic capturing and recording of the OA and its branches in each of the specimens were made. An accurate identification of the arterial system was possible as the arteries were followed intraorbitally from the point where the OA emerged from the optic canal on course with the optic nerve. All branches of the OA that were present were identified and recorded. The application of stamp-pad ink as a dye is useful in the marking and identification of anatomical structures and can be used in the anatomy training for both undergraduate and postgraduate students.

Anemia and idiopathic intracranial hypertension – A coincidence or a correlation

Idiopathic intracranial hypertension (IIH) is commonly seen in females of reproductive age (15–45 years). Here, we report a unique case of a 22-year-old female presenting with complaints of headache and vomiting with a history of polycystic ovarian syndrome for which she was on treatment. The patient had bilateral optic disc edema on fundus examination. Hematological investigations showed severe iron deficiency anemia with hemoglobin 3.7 g/dl. Lumbar puncture showed raised cerebrospinal fluid opening pressure of 270 cm of H2O. Magnetic resonance imaging brain showed partially empty sella and T2 hyperintensity in optic nerve canal, suggestive of IIH. The patient was treated subsequently with blood transfusion followed by iron therapy. After treatment, she showed drastic improvement with the resolution of papilledema and normalization of visual field analysis. Our findings emphasize the importance of hematological investigations and prompt treatment in IIH, which ensure a better prognosis by shortening the disease course.

Radiological study of variations in intersphenoidal septum in a south Indian population- a retrospective cross-sectional study

Introduction and Aim: The anatomical variations in intersphenoidal septum (ISS) will affect the ease of surgery and risk of intraoperative injury to neurovascular structures. It is very important to assess the same in different populations using preoperative imaging. Hence the objective of this study is to determine the prevalence of anatomical variations of intersphenoidal septum and its pattern of attachment among Southern Indian population for better planning of surgery and avoid complications.&#x0D; &#x0D; Materials and Methods: A retrospective cross-sectional analysis of patients who underwent computed tomography paranasal sinus at a tertiary care hospital was done. Data from 186 cases in total were used in this study. The proportion of cases with intersphenoidal septa was the primary outcome evaluated, and the number, location, development, and point of termination of intersphenoidal septa were the secondary outcomes. Statistical software for social studies was used to analyse the data.&#x0D; &#x0D; Results: Absence of intersphenoidal septum was noted in 0.5% of cases with predominant sellar type of pneumatization. Also, single intersphenoidal septum (81.6%), right sided deviation of septum (48.1%), complete formation of intersphenoidal septum (92.4%) and protrusion of septum towards optic nerve canal (45.9%) were the common findings noted in this study.&#x0D; &#x0D; Conclusion: Anatomical variations of the intersphenoidal septum clearly signify that the surgeons should keenly note the variations before planning the surgery.

CT analysis of predictors for visual acuity in optic neuropathy with mucocele

ObjectiveTo evaluate the causative and risk factors for optic neuropathy with mucocele via imaging studies. MethodsWe included 21 patients with rhinogenous optic neuropathy with mucocele. We collected data on the sinus involved, age, sex, number of days from the onset of visual impairment to surgery, and computed tomography (CT) imaging findings (bone defects in the lamina papyracea, Onodi cell mucocele, exophthalmos, and optic nerve deviation). The results were compared between two groups, the one having nine patients with pre-operative visual acuity of <0.1 (the poor group) and the other having 12 patients with pre-operative visual acuity of ≥0.1 (the fair group). Whether or not there was a difference in pre-operative visual acuity between patients with and without Onodi cell mucocele was determined. ResultsAfter surgery, visual acuity improved in 16/21 (76.2%) patients, and a correlation analysis showed a significant positive correlation between pre-operative and post-operative visual acuity. In imaging, the causative sinuses accounted for 85.7% of both posterior ethmoid and sphenoid sinuses. Bone defects of the lamina papyracea at the optic canal and the vertical downward deviation of the optic nerve at each location, especially in 6/9 patients with Onodi cell mucocele, were characteristic in the poor group. In these conditions, increasing the contact areas of the optic nerve and mucocele can leads to more chances of direct downward compression of the optic nerve and infection occurring, and it may lead to severe pre-operative visual impairment. ConclusionImaging studies of optic neuropathy with mucocele help to determine the risk factors and perform early and precise diagnostic imaging and decision-making for surgery.

The Anatomical Landmarks in Endonasal Endoscopic Optic Nerve Decompression Surgery: An Anatomical Study

Aim&#x0D; Optic nerve decompression can be applied for many pathologies that affect the optic canal and the optic nerve. Optic nerve decompression via endonasal endoscopic method is very popular in nowadays with the developments in endoscopic surgery. &#x0D; Material and Methods&#x0D; In this study, the lateral opticocarotid recess (LOCR) and the medial opticocarotid recess (MOCR) which are important anatomical landmarks used during transsphenoidal approach to the opticocarotid region were evaluated. The relations of these anatomical landmarks with each other and with important surrounding landmarks such as optic nerve were examined.&#x0D; Results&#x0D; MOCR were observed in all cadavers on the right side and in 4 of 5 cadavers on the left side. The superior border of the LOCR was measured as 4.85±1.94 mm in average on the right side and 3.93±1.11 mm in average on the left side. The inferior border of the LOCR was measured as 4.72±2.11 mm in average on the right side and 3.98±1.67 mm in average on the left side. The linear distance between the LOCR and the MOCR was measured as 3.11±1.41 mm in average on the right side and 2.46±1.36 mm in average on the left side.&#x0D; Conclusion&#x0D; It is necessary for a safe surgery to reveal the anatomical landmarks and to know the detailed anatomy of this region during optic nerve decompression.

Endoscopic Supraorbital Eyebrow Approach for Medium-Sized Tuberculum Sellae Meningiomas: A Cadaveric Stepwise Dissection, Technical Nuances, and Surgical Outcomes

Tuberculum sellae meningiomas (TSMs) have traditionally been removed using a transcranial approach. In recent years, endoscopic surgery for TSMs has been reported with an expansion of indications. We have performed a fully endoscopic supraorbital keyhole approach for small to medium-sized TSMs and performed radical tumor removal similar to conventional transcranial procedure. We report the details of this surgical procedure including cadaveric stepwise dissection and initial surgical results for small to medium-sized TSMs. We used an endoscopic supraorbital eyebrow approach for 6 patients with TSMs between September 2020 and September 2022. Mean tumor diameter was 16.0 mm (range, 10-20 mm). The surgical approach included an eyebrow skin incision ipsilateral to the lesion, a small frontal craniotomy, subfrontal exposure of the lesion, removal of the tuberculum sellae, unroofing of the optic canal, and resection of the tumor. The extent of resection, preoperative and postoperative visual function, complications, and operative time were evaluated. Optic canal involvement was observed in all patients. Two patients (33%) showed visual dysfunction before surgery. Simpson grade 1 tumor resection was achieved in all cases. Visual function was improved in 2 cases, and remained unchanged in 4 cases. Postoperative pituitary function was preserved in all cases, with no decreases in olfaction. The endoscopic supraorbital eyebrow approach for TSMs allowed resection of the lesion, including tumor extending to the optic canal, with a good surgical view. This technique is minimally invasive for patients and may represent a good surgical option for medium-sized TSMs.