A cadaveric study investigating the anatomy of the medial orbital wall

A review of the ethmoidal foramina and their clinical application

The ethmoidal foramina (EF), located on the medial orbital wall along the frontoethmoidal sutures, are critical anatomical landmarks for surgeries involving the medial orbital wall. This review aimed to review the surgical anatomy of the EF, including their embryology and radiology. Although the frontoethmoidal sutures mostly have two foramina passing through them, there are reports of single foramen or multiple, up to six foramina. These foramina provide a passage for the ethmoidal arteries and nerves, branches of ophthalmic arteries and nerves. The surgical guideline "24-12-6" is based on the approximate distance between the anterior lacrimal crest, the anterior and posterior ethmoidal arteries, and the optic canal, commonly used to navigate this area. However, some studies from various populations defined different ratios. Embryologically, the EF were formed by the union of intramembranous ossified frontal bones and endochondral ossified ethmoid bones. EF and neurovascular structures can be identified in computed tomography even in the 3 mm sectional intervals. A comprehensive anatomical understanding of EF will help clinicians improve surgical guidelines and ultimately reduce the risk of complications.

Exploring the lacrimal sac fossa: anatomical insights for optimizing external dacryocystorhinostomy

BACKGROUND

External dacryocystorhinostomy is considered the gold standard for treating epiphora resulting from nasolacrimal duct obstruction. Despite the success of the procedure, a visible facial skin scar often undermines the surgical outcome. The aim of this study is to prevent visible facial scarring following oculoplastic interventions by improving the insight into the anatomical details of the lacrimal sac fossa (LSF), lacrimo-maxillary suture (LMS), periosteum, and lacrimal diaphragm.

METHODS

The study examined the medial canthal region of eighty adult male sspecimens to investigate the landmarks associated with the LSF. The periorbital area was dissected to reveal the skin, subcutaneous tissues, orbicularis oculi muscles, and the lacrimal drainage system, all of which were detached from their bony attachments. The lengths of the lacrimal crests, midline length, midline width, dorsolateral angle, composition of the LMS, and area of the LSF were evaluated using the ImageJ program. The LSF was categorized into six distinct shapes: ellipsoid, oval, inverted pear, straight pear, oblique hammer, and quadrangular.

RESULTS

The measurements of the anterior lacrimal crest averaged 2.2 ± 0.4 cm, the posterior edge 2.0 ± 0.4 cm, and the midline 1.9 ± 0.3 cm. The area of the LSF was found to be 1.4 ± 0.5 cm². The analysis reveals that about half of the LSF consists of equal parts maxillary and lacrimal bones. The dorsolateral angle values where the maxilla and os lacrimale equally contributed to the structure of the LSF were higher than those completely formed by the maxilla. The shapes of the LSF were classified as ellipsoid (35%), oblique hammer (21.3%), oval (13.7%), inverted pear (15%), with the ellipsoid type being the most frequent. The anterior lacrimal crest length of the oval-shaped LSF was shorter than that of the oblique hammer-shaped LSF. Similarly, the posterior lacrimal crest of the oval-shaped LSF was shorter than that of the oblique hammer-shaped LSF. The midline length of ellipsoid, oval, and inverted pear-shaped LSFs was shorter than that of oblique hammer-shaped LSFs.

CONCLUSION

The length of anterior lacrimal crest and LMS are suggested as the most reliable navigational references for locating the type of LSF. Mastery of the transversal and vertical orientation of the LSF is essential for surgeons performing oculoplastic surgeries tailored to individual anatomical variations. This study is clinically valuable as it underscores the necessity for oculoplastic surgeons to adapt surgical techniques in response to anatomical differences encountered during surgery.

A Systematic and Critical Review on the Anatomy of the Ethmoidal Foramina

PURPOSE

The osteologic anatomy of the orbit is still a field of intense research, particularly as far as vascular channels are concerned. Among them, ethmoidal foraminas (EFs) are certainly those that have more clinical importance and indeed have been deeply investigated. Unfortunately, the vast production of articles, far from clarifying their anatomy, generated a certain degree of confusion.

METHODS

A search on Pubmed and Scopus databases updated up to December 31, 2023, has been carried out with the keyword "ethmoidal foramen" yielding a list of 357 items. With a careful screening process, 31 articles were enlisted to be included in the present review.

RESULTS

A critical review process confirmed that many results published over the years appear inconsistent, particularly as far as EFs topography is concerned. The possible reasons for this lack of consistency can be traced back to inter-ethnical differences, uncertainty on the anterior bony landmarks employed in the investigations, and lack of a general consensus over EFs classification. A novel approach, based on the normalization of the distance of the anterior landmarks relative to the length of the orbit (relative depth index), should overcome some of the major problems encountered so far.

CONCLUSIONS

Novel and clear guidelines to classify EFs and to locate them on the medial wall are required. Determining the relative depth index of EFs may be an interesting approach to solve the matter. Other methods can be also devised. However, direct measurements from bony landmarks, without any further analysis seem inadequate and possibly misleading.

Position of the anterior ethmoidal foramen and trauma to the cranial base during transconjunctival medial orbital decompression: a systematic literature review

PURPOSE

To review the literature on the location of the anterior ethmoidal foramen (AEF) and trauma during transconjunctival medial wall decompression.

METHODS

A comprehensive literature search was conducted using the PubMed, Embase, and Scopus databases, combining the terms "olfactory fossa" and "fovea ethmoidalis" with "trauma," "cerebrospinal fluid leak," "pneumocephalus," "orbital decompression," and "anterior ethmoidal artery" (AEA). All cases of cranial base trauma during medial orbital decompression and the anatomical studies on the location of the AEF and the course of the AEA were reviewed.

RESULTS

Ninety-four articles were identified, of which 37 were related to the AEF, 41 reported the course of the AEA, and 16 to reported cases of cranial base trauma. Out of these cases, 10 were related to transconjunctival medial orbital decompression, affecting 11 patients. Most AEFs are situated at the frontoethmoidal suture, but up to 38.15% of AEFs are located above the suture on the frontal bone. Most AEFs are adjacent to the roof of the ethmoidal sinus. The distance of the AEF to the cranial base increases in the presence of supraorbital ethmoidal cells (SOEC).

CONCLUSIONS

The position of the AEF is variable and should not be considered a safe landmark for all patients.

Practical Considerations in Computerized Surgical Planning for Frontofacial Surgery

The field of frontofacial surgery has advanced considerably, building on the pioneering techniques of Paul Tessier, with computerized surgical planning (CSP) emerging as a critical component. CSP has enhanced the precision and efficiency of surgeries for craniofacial dysostoses and hypertelorism, resulting in improved outcomes. This review delves into the importance of understanding orbital anatomy and the crucial bony and soft tissue landmarks essential to the application of CSP in frontofacial procedures, encompassing Le Fort III and monobloc advancements, as well as the correction of hypertelorism.

Endoscopic-assisted Orbitotomy for Obliteration of Orbital Arteriovenous Fistula Refractory to Endovascular Techniques

Orbital arteriovenous fistula is a rare acquired disorder. The coincidence of arteriovenous fistula with lymphaticovenous malformation is even rarer. The optimal treatment, thus, is controversial. Surgical approaches vary widely, with associated pros and cons. The purpose of this case report is to describe an orbital arteriovenous fistula in a 25-year-old man with congenital fronto-orbital lymphaticovenous malformation, refractory to endovascular techniques, which was later successfully ablated by a direct endoscopic-assisted orbital approach.

Anatomy of lacrimal sac fossa affecting success rate in endoscopic and external dacryocystorhinostomy surgery in Mongolians

To study the affect of anatomical variance of lacrimal sac fossa on dacryocystorhinostomies (DCR) performed by the traditional external (EX-DCR) approach or an endoscopic (EN-DCR) endonasal approach. A total of 292 consecutive cases with primary nasolacrimal obstruction underwent DCR surgery. Orbital computed tomography scan was used to measure lacrimal sac fossa and other related structures and Lac-Q questionnaire was used to compare surgery result. Maxillary portion of lacrimal sac fossa is thicker in failed surgery group than successful surgery group (P<0.05). Lateral nasal structures (uncinate process, operculum of the middle turbinate, agger nasi) are dominantly adjusting to lacrimal sac fossa in failed surgery group (P<0.05). Patients who underwent EX-DCR has a 6.0-point and EN-DCR group 11.0-point improvement (P<0.016) in Lac-Q questionnaire. Patients who have a thick frontal process of the maxilla and uncinate process, operculum of the middle turbinate, ethmoid cells adjusting to lacrimal fossa are prone to have recurrence of nasolacrimal duct obstruction after DCR surgery. The EN-DCR and the EX-DCR approach have an equivalent surgical success rate but improvement in quality of life by using the Lac-Q questionnaire is greater in the endoscopic group when compared with the external.