3D anatomy of the supraorbital and greater occipital nerve trajectories.

PURPOSE: This research aims to enhance understanding of the anatomy of the supraorbital nerve (SON) and greater occipital nerve (GON), focusing on their exit points, distal trajectories, and variability, utilizing a novel 3D representation. METHODS: Ten cadaveric specimens underwent meticulous dissection, and 3D landmarks were registered. Models were generated from CT scans, and a custom 3D method was employed to visualize nerve trajectories. Measurements, including lengths and distances, were obtained for the SON and GON. RESULTS: The SON exhibited varied exit points, with the lateral branches being the longest. The GON showed distinct branching patterns, which are described relative to various anatomical reference points and planes. No systematic left-right differences were observed for either nerve. 3D analysis revealed significant interindividual variability in nerve trajectories. The closest approximation between the SON and GON occurred between lateral branches. CONCLUSION: The study introduces a novel 3D methodology for analyzing the SON and GON, highlighting considerable anatomical variation. Understanding this variability is crucial for clinical applications and tools targeting the skull innervation. The findings serve as a valuable reference for future research, emphasizing the necessity for personalized approaches in innervation-related interventions.

Transorbital Endoscopic Approach to the Foramen Rotundum for Infraorbital Nerve Stripping.

PURPOSE: To develop and evaluate a transorbital endoscopic approach to the foramen rotundum to excise the maxillary nerve and infraorbital nerve branch. METHODS: Cadaveric dissection study of 10 cadaver heads (20 orbits). This technique is predicated upon 1) an inferior orbital fissure release to facilitate access to the orbital apex and 2) the removal of the posterior maxillary wall to enter the pterygopalatine fossa (PPF). Angulations along the infraorbital nerve were quantified as follows: the first angulation was measured between the orbitomaxillary segment within the orbital floor and the pterygopalatine segment suspended within the PPF, while the second angulation was taken between the pterygopalatine segment and maxillary nerve as it exited the foramen rotundum. With refinement of the technique, the minimum amount of posterior maxillary wall removal was quantified in the final 5 cadaver heads (10 orbits). RESULTS: The mean distance from the inferior orbital rim to the foramen rotundum was 45.55 ± 3.24 mm. The first angulation of the infraorbital nerve was 133.10 ± 16.28 degrees, and the second angulation was 124.95 ± 18.01 degrees. The minimum posterior maxillary wall removal to reach the PPF was 11.10 ± 2.56 mm (vertical) and 11.10 ± 2.08 mm (horizontal). CONCLUSIONS: The transorbital endoscopic approach to an en bloc resection of the infraorbital nerve branch up to its maxillary nerve origin provides a pathway to the PPF. This is relevant for nerve stripping in the context of perineural spread. Other applications include access to the superior portion of the PPF in selective biopsy cases or in concurrent orbital pathology.

Morphometric Analysis of the Supraorbital Foramen and Notch in the Population of Bosnia and Herzegovina.

OBJECTIVE: The aim of this study was to learn about the morphological characteristics of the supraorbital foramen and to determine its precise position in relation to the surrounding anatomical landmarks in the adult population of Bosnia and Herzegovina. MATERIAL AND METHODS: For this purpose, 60 skulls from the Bosnia and Herzegovina population of known sex (32 males and 28 females), taken from the osteological collection of the Department of Human Anatomy of the Medical Faculty in Sarajevo, were subjected to morphological and morphometric analysis. Morphometric measurements were performed using a digital vernier caliper (Mitutoyo Corporation, Japan). RESULTS: The study showed that most supraorbital nerves exit the orbit through the supraorbital notch (73.8%) and the rest through the foramen (26.2%). Of this number, bilateral supraorbital notches were recorded in 58.33% of cases, a bilateral supraorbital foramen in 18.34% of cases, while in 23.33% of cases a notch was recorded on one side and a foramen on the contralateral side. Morphometric measurements performed to determine the exact position of the supraorbital foramen relative to the surrounding landmarks showed different values in males and females. An accessory foramen was also observed on the examined skulls in 16.67% of cases. CONCLUSION: Detailed knowledge of anatomical variations of the supraorbital foramen is required for safe and successful administration of regional anesthesia, in order to avoid iatrogenic nerve injuries during orbitofacial region surgery.

The Oculomotor Nerve: Anatomy and Pathology.

The oculomotor nerve is the third cranial nerve, exiting the brainstem in the medial border of the cerebral peduncle, from where it crosses straight to the superior orbital fissure. It is a purely motor nerve responsible for the innervation of all the extraocular muscles, except the superior oblique and lateral rectus muscles. It also has parasympathetic pre-ganglionic fibers, responsible for the innervation of sphincter pupillae and ciliary muscles. Magnetic resonance imaging (MRI) is the best imaging exam to evaluate patients with clinical signs of third cranial nerve palsy. The oculomotor nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. This article aims to review the oculomotor nerve anatomy, discuss the best MRI techniques to evaluate each nerve segment, and demonstrate the imaging aspect of the diseases that most commonly affect it.

Modified procedure for reconstructing the inferior wall of the orbit: identification of a reliable new landmark.

BACKGROUND: In orbital floor reconstruction, fractures involving the slope of the posterior end of the orbital floor make it difficult to determine the best location for implant placement. Therefore, landmarks for reconstruction are desirable to perform safe and reproducible reconstruction surgery. METHODS: We developed a surgical procedure that focuses on three orbital landmarks: the infraorbital nerve, the inferior margin of the greater wing of the sphenoid bone, and the posterior superior wall of the maxilla. CONCLUSIONS: Landmark-based orbital floor fracture reconstruction enables accurate reconstruction of fractures that extend to the slope of the posterior end of the orbital floor.

Preservation of Infraorbital Nerve in Orbital Floor and Maxillary Defect Reconstruction With Patient-Specific Three-Dimensional Implant: A Case Report.

Reconstruction of orbitomaxillary defects poses many operative challenges because it requires consideration of cosmetic as well as functional elements: reestablishing facial symmetry while constituting the orbital volume and preserving involved neurovascular structures. The development of patient-specific polyetheretherketone implants have revolutionized complex craniofacial reconstruction due to its adaptability to anatomic constraints and accommodation of vital structures. Herein, we described 2 cases of orbitomaxillary reconstruction using PEEK implant with novel modifications to preserve the infraorbital nerve with optimal cosmetic outcomes and minimal postoperative morbidity.

Resolution of persistent traumatic supraorbital pain after neuroma excision.

We describe a case of an 18-year-old male who developed a supraorbital neuroma following facial trauma that occurred 2 years earlier. He presented with complaints of persistent facial pain and migraines despite successful laceration repair and removal of foreign bodies at the time of injury. A non-contrast computed tomography (CT) scan of the orbits revealed an enlarged supraorbital nerve with remodeling and expansion of the supraorbital notch, suggesting a neuroma. The patient underwent orbitotomy with excision of neuroma (confirmed histologically) and experienced a complete resolution of periorbital pain.

Comparison of three regional anaesthetic techniques for infraorbital or maxillary nerve block in cats: a cadaveric study.

OBJECTIVES: The maxillary nerve courses very close to the globe, rendering cats - with their large eyes - at risk of globe penetration during infraorbital or maxillary nerve blocks. Therefore, the goals of the study were to compare the distribution and potential complications of three infraorbital or maxillary regional injection techniques. METHODS: Twenty-three bilateral maxillae of cat cadavers were used in a randomised blinded trial. Each maxilla was injected with a 0.2 ml 1:1 mixture of lidocaine 2% and a contrast medium by one of three injection techniques: infraorbital foramen (IOF; n = 14); infraorbital canal (IOC; n = 16); or maxillary foramen (MF; transpalpebral approach; n = 16) using a 25 G 1.6 cm needle. CT imaging of each cadaver head was performed before and after injections. A radiologist scored injectate distribution (none [0], mild [1], moderate [2], large [3]) in four locations: rostral, central and caudal IOC, and at the MF, for which the distribution side was also determined. Comparisons were performed with ordinal logistic mixed effects (P <0.05). RESULTS: The median (range) total distribution score of the IOC and MF technique were significantly higher compared with the IOF technique (6.5 [4-12], 4 [2-8] and 0 [0-10], respectively). The total IOC score was also significantly higher compared with the MF technique. Injectate distribution at the MF was significantly more central following IOC injection compared with MF injection, which distributed centrolaterally. None of the techniques resulted in intraocular injection. CONCLUSIONS AND RELEVANCE: The IOC and MF techniques produced a satisfactory spread of the mixture that could result in effective maxillary anaesthesia in cats. Further studies are required to determine the effectiveness and safety of these techniques.

Hyperintense areas in the intraorbital optic nerve evaluated by T2-weighted magnetic resonance imaging: a glymphatic pathway?

PURPOSE: The present study aimed to explore the glymphatic pathway in the intraorbital optic nerve (ON) using magnetic resonance imaging (MRI). METHODS: Following conventional MRI examination, a total of 89 outpatients underwent T2-weighted imaging in thin-sliced coronal and sagittal sections. Moreover, three injected cadaver heads were dissected. RESULTS: In the cadaver specimens, differences in appearance between the central and peripheral parts of the ON were not observed. On the axial T2-weighted MRI performed in the initial examination, the central part of the intraorbital ONs was delineated as a well-demarcated, linear hyperintense area in 19% of patients. On the thin-sliced serial coronal images, the hyperintense areas were identified on both sides in 91% of patients. They were delineated as continuous hyperintense areas in the ONs with an inconsistent appearance even in the same nerve. In 12.4% of patients, the areas were divided into the upper and lower parts by a horizontal septum, while others showed variable morphologies, lacking a septum. On thin-sliced sagittal images, hyperintense areas were identified in 46% of patients. CONCLUSION: Hyperintense areas in the intraorbital ON detected on T2-weighted sequences may involve a glymphatic pathway with perivascular spaces of the ON and central retinal artery. These may be collapsed and difficult to identify on surgical and cadaver specimens.

Reversal of vision loss after traumatic optic neuropathy.

Traumatic optic neuropathy is sinister sequelae of craniofacial trauma leading to vision loss. The decision between early medical or surgical intervention is usually individualised. Visual evoked potentials may guide the treatment plan. We describe a young male presenting 5 days after a road traffic accident with no perception of light vision in the right eye. He was managed medically with high dose of intravenous steroids. At the 3-month follow-up, he reported a reversal of vision loss with return of visual acuity to 3/60, which improved to 6/36 at 5 months and remained stable at 8 months.

Anatomical study of the supraorbital and supratrochlear nerves: A new classification and application to understanding some migraine headaches.

The frontal nerve is the largest branch of the ophthalmic nerve. This nerve gives rise to two terminal branches, the supraorbital (SON) and supratrochlear nerves (STN). To the best of our knowledge, there are no reports describing the detailed proximal course of these nerves while inside the orbit. Therefore, the goal of this study was to clarify the anatomy of the SON and STN inside and at their exit from the orbit. Twenty sides from ten fresh-frozen cadavers were used in this study. Intra and extra orbital dissections were performed to observe the course of the SON and STN. Additionally, measurements of the nerves were made at these locations. The course of the SON and STN inside the orbit was classified into three groups depending on the STN branching pattern from the SON. The group without any branch from the SON and STN inside the orbit was the most common. The exit points of these nerves were via the supraorbital notch, foramen, or neither a notch nor foramen. A distinct fibrous band was consistently found tethering the nerve except in specimens with nerves traversing a bony foramen. The mean diameters of the SON and STN were 1.3 ± 0.2 and 0.7 ± 0.1 mm, respectively. The results of this study further our knowledge of the course and morphology of the SON and STN and might be useful for better understanding and potentially treating some forms of migraine headache due to SON or STN compression/entrapment. Clin. Anat. 33:332-337, 2020. © 2019 Wiley Periodicals, Inc.

Anatomical variations of the levator palpebrae superioris, including observations on its innervation and intramuscular nerves' distribution pattern.

BACKGROUND: The levator palpebrae superioris muscle (LPS) acts as the upper eyelid's major elevator and retractor and is innervated by the oculomotor nerve. The muscle's paralysis is manifested by ptosis. MATERIAL AND METHODS: 70 orbits were dissected. After removing the orbital roof, the LPS' shape and anatomical variations (i.e., the presence of accessory muscular bands or atypical formation of the muscle) were assessed. To visualize the distribution of the oculomotor nerve's intramuscular sub-branches, the isolated levator palpebrae superioris muscles were stained using Sihler's staining technique. RESULTS: Several LPS anatomical variations were observed in the specimens examined, in seven of which (7/70; 10%) additional delicate muscular slips arose from the LPS' lateral border and reached the lacrimal gland. Histological examination confirmed the presence of striated skeletal muscle fibers in all those cases. In three other specimens (3/70; 4.28%), supernumerary muscular bands ("tensor trochleae") were found that linked the levator with the superior oblique muscle's trochlea. In the next case, the LPS' origin was double and the muscle was bipartite on its proximal half. In most cases (55/70; 78.6%), muscular branches formed a single bundle that wrapped around the superior rectus muscle's medial border to reach the levator's inferior surface. Intramuscular sub-branches were distributed largely within the proximal two-thirds of the LPS and formed an irregular, tree-like pattern. However, thin sub-branches and small retrograde sub-branches extended as far as the muscle's insertion. CONCLUSIONS: Plastic surgeons and ophthalmologists should be aware of the levator palpebrae superioris muscle's anatomic variations both in planning and conducting surgeries on the upper eyelid.

Anatomic Factors Predicting Postoperative Strabismus in Orbital Wall Fracture Repair.

This study is aimed to determine the relationship between orbital fracture sites in each CT scan view and postoperative diplopia. Data for 141 patients of orbital wall fracture were analyzed retrospectively. One group of examiners reviewed sagittal, coronal and axial CT scans. Descriptive statistical analysis was used to assess each fracture area and its potential relationship with the occurrence of postoperative diplopia. Among the three anatomical views, sagittal sections were significantly associated with post-operative diplopia (PD) (p = 0.044). For orbital wall fractures in a single location, C1 (p = 0.015), A1 (p = 0.004) and S3 (p = 0.006) fractures were significantly related to PD. Orbital wall fractures found in more than one location resulted in a higher probability of PD in all sections:, C1 + C2 group (p = 0.010), C1 + C2 + C3 group (p = 0.005), A1 + A2 group (p = 0.034), A3 + A1 group (p = 0.005), S1 + S2 group (p < 0.001), S2 + S3 group (p = 0.006) and S1 + S2 + S3 group (p < 0.001). For combinations of two or three sections, we found that only fractures involving both coronal and sagittal sections led to a significantly increased risk of PD (p = 0.031). PD is the main posttreatment complication of orbital bone fracture reduction. In addition to the known myogenic cause (failure to relieve entrapment) of diplopia, both trauma and surgical manipulation can compromise ocular motor nerve function and possibly result in the development of neurogenic causes of diplopia. Careful assessment of patient symptoms (whether preoperative diplopia is present), and the location of orbital fractures (and the influence of related musculature, fat, and nerves) on CT scans are strongly related to surgical success.

Ex Vivo Oculomotor Slice Culture from Embryonic GFP-Expressing Mice for Time-Lapse Imaging of Oculomotor Nerve Outgrowth.

Accurate eye movements are crucial for vision, but the development of the ocular motor system, especially the molecular pathways controlling axon guidance, has not been fully elucidated. This is partly due to technical limitations of traditional axon guidance assays. To identify additional axon guidance cues influencing the oculomotor nerve, an ex vivo slice assay to image the oculomotor nerve in real-time as it grows towards the eye was developed. E10.5 IslMN-GFP embryos are used to generate ex vivo slices by embedding them in agarose, slicing on a vibratome, then growing them in a microscope stage-top incubator with time-lapse photomicroscopy for 24-72 h. Control slices recapitulate the in vivo timing of outgrowth of axons from the nucleus to the orbit. Small molecule inhibitors or recombinant proteins can be added to the culture media to assess the role of different axon guidance pathways. This method has the advantages of maintaining more of the local microenvironment through which axons traverse, not axotomizing the growing axons, and assessing the axons at multiple points along their trajectory. It can also identify effects on specific subsets of axons. For example, inhibition of CXCR4 causes axons still within the midbrain to grow dorsally rather than ventrally, but axons that have already exited ventrally are not affected.

Anatomical Variations of the Supraorbital and Supratrochlear Nerves: Their Intraorbital Course and Relation to the Supraorbital Margin.

BACKGROUND This study aimed to describe the topographical anatomy of the supraorbital and supratrochlear nerves. Anatomical variations of both the intraorbital course of the 2 nerves and their relation to the supraorbital margin were analyzed. MATERIAL AND METHODS The research material involved 50 isolated adult cadaveric hemi-heads and 25 macerated adult skulls. All studied specimens were of Caucasian origin. RESULTS Taking into account the location of the frontal nerve division, 2 main variants of the intraorbital course of the supraorbital and supratrochlear nerves were distinguished. The first variant (variant I, 42%) involved cases in which the supraorbital and supratrochlear nerves branched off from the frontal nerve in the distal half of the length of the orbit. In the second variant (variant II, 58%), the frontal nerve branched into the supraorbital and supratrochlear nerves in the proximal half of the orbit. Variant II was characterized by the presence of a thick supraorbital nerve and a long, tiny supratrochlear nerve. For variant I, 27.8% of the supraorbital nerves were divided into the medial and lateral branch within the orbit, whereas, for variant II, 75% of nerves were divided into the medial and lateral branch within the orbit (before crossing the supraorbital margin). Single passage was observed on the supraorbital margin in 80% of wet specimens and in 78% of orbits examined on the macerated skulls. CONCLUSIONS Both the intraorbital and extraorbital course of the branches of the supraorbital and supratrochlear nerves were highly diverse. These variations should be taken into account during medical procedures performed within the orbital and frontal regions.

Lateral Antebrachial Cutaneous Nerve as Autologous Graft for Mini-Invasive Corneal Neurotization (MICORNE).

PURPOSE: We describe the first case of a novel surgical technique of mini-invasive corneal neurotization (MICORNE) using the lateral antebrachial cutaneous nerve as a graft nerve and the contralateral supraorbital nerve as a donor nerve in a herpetic patient with a neurotrophic keratopathy (NK). METHODS: A MICORNE procedure was performed in a 32-year-old man with a 5-year history of herpes simplex virus (HSV)-related NK in the right eye (RE). Visual acuity and corneal sensation were assessed over 9 months of follow-up. HSV-1 and HSV-2 genomes were screened preoperatively and postoperatively in the patient's tears using the quantitative polymerase chain reaction technique. A high does of the oral antiviral prophylaxis was prescribed during the follow-up. RESULTS: Preoperative best-corrected visual acuity was 20/200 in the RE. A Cochet-Bonnet esthesiometer revealed complete corneal anesthesia (<5 mm ie, >15.9 g/mm) in all quadrants in a scarred and neovascularized cornea. Twelve months after the procedure, the visual acuity of the RE was 20/80 and corneal sensitivity had increased to 40 mm, that is, 0.8 g/mm (superior quadrant), 35 mm, that is, 1 g/mm (inferior quadrant), 40 mm (temporal quadrant), 35 mm, that is, 1 g/mm (nasal quadrant), and 40 mm (centrally). We observed no clinical recurrence of herpes, and HSV was not detected in tears during the follow-up period. CONCLUSIONS: We report the first case of MICORNE, a novel surgical technique of corneal neurotization in a herpetic patient with NK. Despite the potential risk of viral recurrence, our patient showed dramatic improvement in corneal sensation and visual acuity.

Surgical anatomy of the orbit. A systematic and clear study of a complex structure. / Anatomía quirúrgica de la órbita. Un estudio sistematizado y claro de una estructura compleja.

BACKGROUND AND OBJECTIVE: The orbit is a structure of interest for many medical specialties. Surgical approaches to the orbit present significant difficulties for the general neurosurgeon. Whoever decides to practice orbital surgery must have vast anatomical knowledge of this structure. However, although many of the existing publications about orbital anatomy show the complexity of this structure in detail, they fail to facilitate their understanding. The purpose of this study was to systematise and simplify the anatomical study of the orbit from a surgical perspective, to facilitate its understanding. MATERIALS AND METHODS: A review of the international literature on the subject was carried out, and the principle of the rule of 7was followed for its ordering. For illustration purposes, photographs of cadaveric preparations and digital drawings were used. RESULTS: The orbits are 2cavities located symmetrically on both sides of the nose. They have a pyramidal shape, with 4sides, a posterior vertex, an anterior base and their axis established from the sagittal plane at a 20-degree angle. A distinctive feature of the orbit is that its elements are organised into groups of seven: 7bones, 7intraorbital extraocular muscles and 7nerves. CONCLUSION: A systematisation of the orbital anatomy was performed with clear illustrations to simplify its study. The understanding of the anatomy of the orbit is vital to classify lesions and provides a solid basis when choosing the most appropriate approach for their treatment.

Ultrasound-guided posterior extraconal block in the dog: anatomical study in cadavers.

OBJECTIVE: To describe a novel ultrasound-guided posterior extraconal block in the dog. STUDY DESIGN: Prospective experimental cadaveric study. ANIMALS: A total of 13 Beagle Cross cadaver heads. METHODS: After describing the ultrasound bony landmarks and posterior extraconal local regional technique in one head, 12 heads were used to evaluate the spreading of contrast and evaluate potential complications. A 5-8 MHz microconvex ultrasound probe was positioned caudal to the orbital ligament, with the beam orientated transversely, and then tilted caudally until the orbital fissure was visualized. After identifying the bony structures consistent with the orbital fissure, a needle was advanced using an in-plane technique and 0.5 mL of a 50:50 mixture of iohexol and methylene blue was injected. Computed tomography (CT) and dissection were used to evaluate successful injections and potential complications. The injection was considered successful if radiopaque contrast medium was 5 mm from the orbital fissure. Potential complications were defined as the presence of radiopaque contrast within the globe or the intracalvarial tissues. RESULTS: The CT images confirmed contrast at the target site in 15/24 (63%) of the injections. Only two injections were found in the temporalis muscle; the rest of the injections were located in the extraconal space. No potential complications such as intracranial spreading of contrast, intravascular or intraocular injection were found. CONCLUSIONS AND CLINICAL RELEVANCE: The technique can deliver contrast close to the main nerves which provide sensory and motor innervation to the eye. Further studies are needed to evaluate this technique in clinical cases.

Visualization of the supraorbital notch/foramen using magnetic resonance imaging.

The supraorbital notch/foramen involving the segment of the supraorbital nerve (SON) and the supraorbital artery (SOA) has little been explored with magnetic resonance imaging (MRI). Therefore, we explored these structures using MRI. A total of 90 patients underwent thin-sliced contrast MRI. In addition, eight sides of the orbits were dissected in four cadaveric heads. Cadaver dissections showed that the SOA coursed consistently beneath and in close proximity to the SON and reached the supraorbital notch/foramen. On axial MRI images, the supraorbital notch/foramen was identified in 98% on the right side and in 99% on the left. The distance from the midline to the midpoint of the supraorbital notch/foramen and depth from the skin surface to the supraorbital foramen/exit were measured. The median distance was 22.6 ±â€¯3.08 mm on the right side and 22.8 ±â€¯3.07 mm on the left, whereas the depth was 7.7 ±â€¯1.39 mm on the right and 7.7 ±â€¯1.43 mm on the left. Eighty percent of the sagittal images showed well-developed diploic veins in the supraorbital rim. Of these, 8.3% had anastomotic channels with the subcutaneous veins through the anterior wall of the supraorbital rim, 11.8% through the inferior wall, and 9% through the SOF. The SON and SOA segments passing through the supraorbital exit can be reliably located using contrast MRI. The supraorbital rim may function as the intracranial to extracranial anastomotic channel.