Supraorbital Notch and Foramen: Positional Variation and Relevance to Direct Brow Lift

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.

Evaluation and Classification of Supraorbital Nerve Emerging Patterns

BACKGROUND

Numerous significant variations in the supraorbital nerve (SON) pass through the notches and foramina. During endoscopic forehead lifting, the passage and the location of the nerve against the frontal bone render it susceptible to injury, resulting in diminished or absent sensation in the corresponding location. We attempted to obtain accurate knowledge of the SON emergence routes.

METHODS

Data of patients who underwent an endoscopic forehead lift in a plastic surgery clinic between November 2015 and August 2021 were retrospectively analyzed. Deep and superficial branch pathways of SONs were identified and compared according to side and gender. We also classified the nerve patterns into six types.

RESULTS

Altogether, 942 patients (1884 SON cases) were evaluated. Out of the patients, 86 patients were male, and 856 were female. The overall mean age was 48.6 (± 13.1) years. In the deep branches, 49% came from the notch, and 51% came from the foramen. In the superficial branches, 67% came from the notch, and 33% of superficial branches came from the foramen. Unlike the deep branch, superficial branches from the notch were significant. Deep and superficial branches of male patients were much more notched than those of female patients. Branches emerged together in 56% and separately in 44% of the cases.

CONCLUSION

The absolute number of SON notches was higher than that of SON foramina. This study with the largest number of SON cases will help surgeons understand the variation and course of SON.

LEVEL OF EVIDENCE IV

This journal requires that authors 38 assign a level of evidence to each article. For a full 39 description of these Evidence-Based Medicine ratings, 40 please refer to the Table of Contents or the online 41 Instructions to Authors www.springer.com/00266 .

Suspect graveyard burial (South Armagh, N. Ireland): Combined search, forensic anthropology and radiocarbon dating

Geophysical investigation of a former convent graveyard for conversion to a community centre identified an unrecorded, unmarked burial below a later burial. Archaeological excavation confirmed the presence of skeletonized human remains, considered by police as a possible clandestine burial. Mortuary examination indicated the remains belonged to a mature adult female. To determine whether the deceased could be a recorded missing person, radiocarbon dating was undertaken on a femur and a rib bone. This is not always straightforward, and results showed two possible ages due to intercepts on either side of the nuclear weapons testing spike in atmospheric ¹⁴C; however, the later dated burial allowed us to constrain the date of a rib to CE 1959. This study demonstrates that dating a second tissue with a longer turnaround time, such as a femur, can help to constrain which side of the bomb spike is most probable. This paper documents in one work the search, scene and sample and then advances this to resolution by anthropological analysis and radiocarbon dating of human remains.

Anatomical considerations of cutaneous nerves of scalp for an effective anesthetic blockade for procedures on the scalp

Objective

The anatomy of the scalp nerves varies widely with age, race, and individuals of the same race and even within the same individual and hence need to be studied extensively to avoid complications and improve effectiveness during various surgical and anesthetic procedures of the scalp.

Materials and Methods

Gross dissection was carried out on 11 cadavers (22 Hemifaces: 11 right and 11 left) with no obvious scalp deformities or surgeries. The distances of the supraorbital nerve (SON), supratrochlear nerve (STN), and greater occipital nerve (GON) from commonly used bony landmarks were measured. The branching pattern and presence of accessory notches/foramina were noted.

Results

SON and STN were found almost midway and at the junction between medial and middle one-third of the line joining midline and lateral orbital margin, respectively. The distances of STN and SON from the midline were about ½ and 3/4th of the transverse orbital diameters of the individual. GON was found at the medial 2/5 and lateral 3/5 of the line joining inion to the mastoid. In 40.9% cases, SON gave three branches while STN and GON remained as single trunks in 77.27% and 40.0% cases, respectively. Accessory foramina/notches for SON and STN were found in 36.36% and 4.54% of the specimen, respectively. SON and STN remained lateral in the majority while GON ran medially to corresponding vessels.

Conclusion

These parameters on the Indian population would give a comprehensive idea of the distribution of these cutaneous scalp nerves and would be beneficial in the targeted and accurate deposition of local anesthetic.

Precision Analysis of Supraorbital Transcranial Exits Using Three Dimensional Multidetector Computed Tomography

PURPOSE

Anatomical variation in supraorbital transcranial exits, which can be divided into the lateral supraorbital exit and the medial frontal exit, has been investigated in several studies during the past few decades. However, in previous studies, inconsistent criteria were used for classifying those exits. The authors analyzed variations in supraorbital transcranial exits using 3 dimensional multidetector computed tomography (3D MDCT), and present a consistent classification of the types of those exits with precise location measurements.

METHODS

In 1181 patients (2362 orbits) who underwent facial 3D MDCT, the authors measured a set of qualitative and quantitative parameters. The qualitative parameters included an assessment of the location and type of the exit, and the number of accessory foramina. The quantitative parameters included various distance measurements.

RESULTS

A frontal exit was present in 2071 orbits and a supraorbital exit in 953. Neither a frontal exit nor a supraorbital exit was found in 11 orbits. The most common type of frontal exit was the notch type, followed by the foramen type and none. The mean distance from the nasion to the frontal exit was 24.70 ± 3.50 mm on the right side and 23.69 ± 3.42 mm on the left side.

CONCLUSION

In conclusion, various types of supraorbital transcranial exits were observed, of which the frontal notch was the most common. This is the first study to conduct a consistent analysis of a large sample of skulls to characterize the distribution of supraorbital transcranial exit types using a comprehensive and clear set of criteria.

Facial Nerve Preservation for Supraorbital Approaches: Anatomical Mapping Based on Consistent Landmarks

BACKGROUND

The supraorbital keyhole approach (SOKA) provides a safe and advantageous access to the anterior cranial fossa. The implemented skin incision varies depending on surgeon's preferences and requirements. Facial nerve (FN) injury might appear in up to 5.6% of patients. There is a lack of validated tenets for avoiding FN injury.

OBJECTIVE

To define a safety area for FN preservation during a SOKA.

METHODS

Ten dried skulls and 5 injected cadaveric heads (10 sides) were used. A Cartesian frame was created with its horizontal axis at the level of the supraorbital notch and the vertical axis just lateral to the frontozygomatic junction (FZj). FNs were dissected and points along their course were registered and transferred to the Cartesian frame.

RESULTS

Ten microscopic dissections of the FN were performed preserving all branches. A safety area could be defined 8 mm superior and 10 mm inferior to the FZj extending medially to the supraorbital notch and beyond. A 20 mm2 area superior and lateral to the FZj provided low probability (≤10%) of injuring the FN. Similarly, starting 4 mm inferior to the FZj, a lateral safety area was also found. A probabilistic colored heat map was built to represent the results.

CONCLUSION

We provide a "safety zone" for a SOKA incision in which the probability to encounter the FN is low. Clinical studies following our method may validate our findings and add evidence to the tenets for minimizing morbidity related to the SOKA incision.

[An anatomical study on the applicability of direct endoscopic exclusion of the ethmoid arteries for devascularization of the anterior skull base structures]

The anterior skull base structures are the site of initial growth of histologically different tumors. The difficulties in their removal are often associated with significant vascularization, which may limit the amount of resection due to abundant intraoperative blood loss. Midline tumors are primarily fed by the ethmoid arteries that are not accessible to embolization. The aim of this work was a comparative experimental study of various direct approaches to the ethmoid arteries.

MATERIAL AND METHODS

The study was conducted on anatomical specimens of 12 cadaveric heads of deceased people without pathology of the anterior skull base structures, orbits, nasal cavity, and paranasal sinuses (24 sides). In all specimens, the internal and external carotid arteries were stained with silicone. During anatomical dissection, four surgical approaches for exclusion of the ethmoid arteries were studied: 1) transorbital approach to the arteries using a bicoronal incision; 2) endoscopic retro-caruncular approach; 3) endoscopic endonasal transethmoidal approach to the ethmoid artery canals; 4) endoscopic endonasal transethmoidal transorbital approach to the ethmoid arteries in the orbit.

RESULTS

We described a surgical technique for exclusion of the ethmoid arteries using the approaches and analyzed their advantages and disadvantages. We formulated an algorithm for choosing the method for direct endoscopic exclusion of the ethmoid arteries, depending on the surgical approach chosen for removal of the tumor and features of the tumor extracranial spread.

CONCLUSION

The decision on tumor devascularization is based on assessment of tumor blood supply (CT angiography or MR angiography data). Our study demonstrated the advantages and disadvantages of various approaches to the ethmoid arteries for their exclusion in order to early devascularize anterior skull base tumors. All these approaches are less traumatic and characterized by a good cosmetic and functional outcome.

Supraorbital nerve exits: positional variations and localization relative to surgical landmarks

Significant variations exist in the occurrence, form, and position of supraorbital nerve exits through the frontal bone. Detailed knowledge of the positional variations of supraorbital exits is important to ensure safe and successful regional anesthesia, and to avoid iatrogenic nerve injuries during surgery of the orbitofacial region. Supraorbital nerve exits from 116 sides of 58 dry intact adult skulls (37 male and 21 female) in a Sri Lankan population were examined to determine the morphological features and the precise position in relation to the facial midline, temporal crest of frontal bone, and frontozygomatic suture. A majority of supraorbital nerve exits existed as notches (73.8%) and the rest as foramina (26.2%). Accessory exits were seen in 18.9% skulls. Of the skulls examined, 55.1% displayed bilateral supraorbital notches, 8.6% had bilateral supraorbital foramina, and 36.3% had a notch on one side and a foramen on the contralateral side. In males, the supraorbital nerve exit was located 23.64±3.49 mm laterally from the facial midline, 27.86±2.76 mm medially from the temporal crest of the frontal bone, 28.66±2.56 mm from the frontozygomatic suture, and 2.12±1.07 mm above the supraorbital margin in the case of a foramen, and in females 22.69±3.28 mm laterally from the facial midline, 26.32±3.02 medially from temporal crest of frontal bone, 27.29±3.05 from the frontozygomatic suture, and 2.99±1.49 mm above the supraorbital margin when it existed as a foramen. The observations made in this study will be useful when planning a supraorbital nerve block and surgery in the supraorbital region.

Topography of the supraorbital nerve with reference to the lacrimal caruncle: danger zone for direct browplasty

PURPOSE

To elucidate the course of the supraorbital nerve (SON) with reference to the lacrimal caruncle in order to facilitate safer direct browplasty by preventing nerve injury.

METHODS

Thirty-four hemifaces from 18 embalmed Korean cadavers were dissected. A vertical line through the upmost point of the lacrimal caruncle and a horizontal line through the supraorbital margin were used as the horizontal and vertical reference positions, respectively. The course of the SON in the frontal view and the point at which it pierced the overlaying musculature were examined.

RESULTS

The SON divides into a superficial branch and a deep branch just after exiting the orbit. In all cases, the deep SON remains in the subgaleal plane deep to the corrugator and frontalis muscles. The superficial SON travels under the corrugator muscle dividing into three branches (medial, intermediate and lateral) and pierced the frontalis muscle at 19-32 mm above the supraorbital margin. However, in 11 cases (32%) the medial branch of the superficial SON pierced the lower portion of the corrugator muscle at 3.6 mm above the supraorbital margin and ran in front of the muscle along with the vertical line through the upmost point of the lacrimal caruncle.

CONCLUSIONS

One-third of the medial branch of the superficial SON without corrugator muscle protection is vulnerable to iatrogenic injury during direct browplasty. Therefore, the oculofacial surgeon must bring the dissection plane of the forehead tissue more superficially around the vertical line through the upmost point of the lacrimal caruncle in order to avoid nerve injury.

Anterior and Posterior Ethmoidal Artery Ligation in Anterior Skull Base Meningiomas: A Review on Microsurgical Approaches

OBJECTIVE

Anterior skull base neoplastic and vascular lesions can receive significant blood supply from the anterior and posterior ethmoidal artery. Although useful in preoperative embolization of middle meningeal artery branches, endovascular techniques for the occlusion of anterior ethmoidal artery expose the parent vessel, the ophthalmic artery, to possible embolic complications, which can cause loss of vision. When dealing with anterior fossa giant meningiomas, moreover, it is not always possible to gain direct intracranial access to anterior ethmoidal arteries because of dimensions and invasiveness of these neoplasms. The aim of this review is to illustrate the anterior and posterior ethmoidal artery anatomy and the microsurgical approaches for extracranial ligation.

METHODS

We performed a literature review of the relevant microsurgical anatomy of these arteries; particular attention is given to anterior cranial fossa and medial orbital wall anatomy.

RESULTS

Our research found two surgical sites of arterial occlusion that can be best exposed with five microsurgical approaches.

CONCLUSIONS

A combination of different surgical and endovascular techniques before resection of hypervascular giant olfactory groove and planum sphenoidale meningiomas should always be considered. Microsurgical extracranial ligation of anterior and sometimes posterior ethmoidal arteries provides a safe and feasible option to limit blood loss during anterior skull base surgery.

Recent Advances in Ophthalmic Plastic Surgery: Part 1-Eyelid

PURPOSE

The objective of this study was to provide an update of the current literature in ophthalmic and facial plastic surgery, specifically related to disorders of the eyelid.

DESIGN

This was a review of published literature from January 2012 to June 2013 METHODS: The authors conducted a PubMed literature search of English-language articles published between January 2012 and June 2013 using the following search terms: eyelid, congenital, acquired, infection, inflammation, trauma, tumor, ptosis, entropion, ectropion, lagophthalmos, botulinum toxin, fillers, blepharoplasty, and miscellaneous topics related to the disorders of the eyelid. The authors included original articles, review articles, and case reports with relevant new information that is of potential clinical use to a comprehensive ophthalmologist as well as to the subspecialist.

RESULTS

Current literature on the disorders of the eyelid is replete with useful clinical information of relevance to a practicing ophthalmologist. Major advances have been reported in understanding of the surgical anatomy and its applications, ptosis, entropion, ectropion, lagophthalmos, infection, inflammation, trauma, and tumors.

CONCLUSIONS

There seems to be tremendous excitement in revisiting the anatomy and pathology and modifying the management protocols and surgical procedures to achieve optimal results, as the subspecialty continues to advance at a brisk pace.