A cadaveric study of the morphometric relationships and bony composition of the caucasian nasolacrimal fossa

Computed tomographic assessment of the lacrimal sac fossa in southwest population of Iran

To determine the morphology of the lacrimal sac fossa and bony nasolacrimal duct using computed tomography for obtaining detailed anatomical understanding of the drainage system and utilizing these measurements in planning for dacryocystorhinostomy (DCR) and nasolacrimal duct (NLD) obstruction in normal southwest (SW) population of Iran. One-hundred-sixty-five cases referred for the diagnosis of neuro-ophthalmic conditions were retrospectively studied. Measurements of lacrimal sac fossa were taken on three anatomical sections (upper, middle, and lower planes) utilizing a digital caliper/protractor instrument. Lacrimal thickness and two measurements of maxillary bone thickness were taken at each plane—namely, the “midpoint thickness” and the “maximum thickness.” The anterior extent of the nasal mucosa and NLD width was also evaluated. The mean maximum thickness of the maxillary bone at the three anatomical planes of the lacrimal sac fossa was 4.07 mm, 4.78 mm, and 5.60 mm, respectively. The midpoint thickness of the maxillary bone at each plane was 2.38 mm, 1.99 mm, and 1.68 mm, respectively, in both sexs. The lacrimal bone thickness at each level was 0.76 mm, 0.69 mm, and 0.67 mm, respectively. The proportion of the lacrimal sac fossa comprising the lacrimal bone at lower plane was 43.57% and showed a positive correlation with age (P=0.01). The mean anteroposterior bony nasolacrimal diameter was 5.94 mm with no significant difference between patient sex and age. According to the results, its indicate that performing an osteotomy during DCR could be easier in the Iranian SW population compared to other ethnics.

Computed tomographic assessment of the lacrimal sac fossa in the Japanese population

PURPOSE

To analyze the morphology of the lacrimal sac fossa in the Japanese population using computed tomographic images.

MATERIALS AND METHODS

One-hundred-fifty-five Japanese patients diagnosed with unilateral orbital fracture were retrospectively reviewed. Measurements of the dimensions of the lacrimal sac fossa were taken on three anatomical planes (upper, middle, and lower planes) using a digital caliper/protractor tool.

RESULTS

The mean maximum thickness of the maxillary bone at the upper, middle, and lower planes of the lacrimal sac fossa were 4.60 mm, 5.07 mm, and 6.30 mm, respectively. The midpoint thickness of the maxillary bone at each plane were 3.04 mm, 3.00 mm, and 2.17 mm, respectively. The lacrimal bone thickness at each plane were 1.13 mm, 1.13 mm, and 1.08 mm, respectively. The proportion of the lacrimal sac fossa comprising of the lacrimal bone at each plane were 39.00%, 42.05%, 38.92%, respectively. On the middle plane, the mean angle between the lacrimal bone and sagittal plane was 131.92°.

CONCLUSIONS

In Japanese patients, the proportion of the lacrimal bone on the lacrimal sac fossa tended to be of greater proportion compared to studies done on other races. The mean angle of the lacrimal sac fossa seemed to be comparatively high. These results indicate that performing an osteotomy during dacryocystorhinostomy could be relatively easier in the Japanese population compared to other races.

Anatomical considerations in endoscopic lacrimal surgery

PURPOSE

To provide a review of the anatomy of the lacrimal drainage system and lateral wall of the nose pertaining to endoscopic dacryocystorhinostomy.

METHODS

The authors performed a PubMed search of articles published pertaining to the anatomy of the lateral wall of the nose and the anatomy of endonasal and external dacryocystorhinostomy surgery.

RESULTS

The article covers the regional surface and surgical anatomy for endoscopic dacryocystorhinostomy (DCR), including the maxillary line, middle turbinate, agger nasi air cell, lacrimal sac and fossa and the upper portion of the nasolacrimal drainage system. It also explores the dimensions and location of bony ostium formation to ensure full exposure and marsupialisation of the lacrimal sac. Finally, it covers the anatomy of potential complications of endoscopic DCR surgery including penetration of the skull base and orbit, inadvertent entry to the maxillary sinus and breach of the skin.

CONCLUSION

A good understanding of the anatomy of the lacrimal drainage system and the lateral wall of the nose will increase the likelihood of successful surgery and minimize the risk of complications and damage to neighbouring structures such as the orbit and skull base.

Morphology and morphometry of lacrimal drainage system in relation to bony landmarks in Caucasian adults: a cadaveric study

PURPOSE

The objective of this study is to examine the morphometry of the lacrimal drainage system with reference to bony landmarks in the vicinity.

METHODS

Twenty midsaggitalized heads obtained from sixteen preserved cadavers were studied. Measurements involved detailed morphometry of anterior and posterior lacrimal crests, bony lacrimal sac fossa, entrance and length of the bony nasolacrimal duct (NLD), attachment of Horner's muscle, and characteristics of the inferior meatal opening of the NLD.

RESULTS

The mean lengths of anterior and posterior lacrimal crests were 16.3 and 12.5 mm, respectively. At the midpoint of the posterior lacrimal crest, Horner's muscle was found to be attached at a mean of 1.3 mm posterior to the crest. The mean dimensions of the bony lacrimal sac fossa at superior, mid and inferior levels were 6.5, 8.7, and 5.9 mm, respectively. The mean contribution of the lacrimal bone to the lacrimal sac fossa was 56.2%. The mean anteroposterior and transverse diameters of the entrance of the bony NLD were 5.7 and 4.7 mm, respectively. The most common type of NLD opening in the inferior meatus was that of "vertical sulcus" (70%, 14/20). The mean distance of the NLD opening from the anterior nasal spine and Limen nasi were 22.2 and 18.9 mm, respectively.

CONCLUSION

This study provides useful anatomical and positional relationship of bony lacrimal landmarks and nasolacrimal duct in Caucasian adults.

Measurement of Lacrimal Sac Fossa Using Orbital Computed Tomography

PURPOSE

To evaluate the clinical usefulness of measuring the lacrimal sac fossa length using orbital computed tomography in normal Koreans.

METHODS

The authors retrospectively evaluated 140 patients (70 males and 70 females) who underwent orbital computed tomography at Guro Hospital and who had no history of orbital disease or orbital trauma. Computed tomography scans of the right orbit, including the proportion of the lacrimal bone and maxillary bone that comprise the lacrimal sac fossa, were evaluated at 3 different axial planes (lower, middle, and upper levels). Additionally, the mid-point thickness and maximum thickness of the maxillary bone were measured. Finally, the authors also evaluated the relationship between nasal bone height and maxillary bone thickness in the lacrimal sac fossa.

RESULTS

Maxillary bone thickness in the lacrimal sac fossa was thicker in males than in females at mid-point thickness and maximum thickness (P < 0.05). However, there was no significant difference in the size of the lacrimal sac fossa and the proportion of the maxillary bone between males and females.In comparisons between maxillary cross-sections, bone thickness was greater toward the upper level of the lacrimal sac fossa (P = 0.008), and the proportion of the maxillary bone was also greater (P = 0.006).Aging had a significant positive correlation with maxillary bone thickness at all 3 axial planes (P < 0.05), but there was no relationship between age and maxillary bone proportion. Nasal bone height and maxillary bone thickness were also not significantly related.

CONCLUSION

In comprising the lacrimal sac fossa, the maxillary bone accounted for a bigger proportion than the lacrimal bone. Male maxillary bone thickness was greater than female thickness. The authors also observed that maxillary bone thickness increased toward the upper areas of the lacrimal sac fossa and with increasing subject age. Understanding the form and variation of a normal lacrimal sac fossa is helpful for preparing for a successful osteotomy with endoscopic dacryocystorhinostomy.

Minimally invasive medial maxillectomy and the position of nasolacrimal duct: the CT study

Several minimally invasive modifications of endoscopic medial maxillectomy have been proposed recently, with the least traumatic techniques utilizing the lacrimal recess as a route to enter the sinus. The aim of the study was to analyze the anatomy of medial maxillary wall in the region of nasolacrimal canal and, thus, to determine the capability of performing minimally invasive approach to the maxillary sinus leading through the lacrimal recess. The course of nasolacrimal canal and the distance between the anterior maxillary wall and the nasolacrimal canal (the width of lacrimal recess) were evaluated in 125 randomly selected computed tomography (CT) head examinations. The proportion of cases with unfavorable anatomical conditions (lacrimal recess too narrow to accept a 4 mm optic) to perform minimally invasive middle maxillectomy was assessed. The width of lacrimal recess, measured at the level of the inferior turbinate attachment, varied between 0 and 15.2 mm and was related to slanted course of nasolacrimal canal. The more perpendicular the axis of the canal to the nasal flor, the narrower the lacrimal recess. In about 16% of cases, lacrimal recess width was less than 4 mm and in 14.4% it was missing. The endoscopic approach to maxillary sinus leading through lacrimal recess is possible in about 70% of patients. In the remaining group of patients when the lacrimal recess is too narrow, this type of approach may be difficult to perform without damaging the piriform aperture rim or bony framework of nasolacrimal duct, or it may be impracticable when lacrimal recess is missing.

Radiological Comparison of the Lacrimal Sac Fossa Anatomy Between Black Africans and Caucasians

PURPOSE

To compare, in black Africans and Caucasians, the radiological anatomy of the intranasal structures and lacrimal sac fossa as relevant to dacryocystorhinostomy.

METHODS

0.75 mm section cranio-orbital computed tomography scans from 72 patients (42 black Africans and 30 Caucasian) were included in this retrospective observational case series. Only one orbit from each scan was utilized. The main outcome measures were: the thickness and proportions of the lacrimal bone and frontal process of the maxilla evaluated at 3 axial planes (upper, middle, lower) in the lacrimal sac fossa; 2 measurements of maxillary thickness were obtained at each plane-namely, the "midpoint thickness" and the "maximum thickness." The anterior extent of the nasal mucosa was also evaluated.

RESULTS

The frontal process of the maxilla was thickest inferiorly (p < 0.001) and the maximum maxillary thickness was significantly thicker in black Africans as compared with Caucasians (p < 0.001) at all planes. At midfossa level, the proportion of maxillary bone forming the lacrimal fossa wall was significantly greater in black Africans (p < 0.01). In contrast, the length of nasal mucosa available for creation of an anastomosis, as estimated from the greatest mucosal height, was significantly greater in Caucasians (p < 0.01).

CONCLUSIONS

Black Africans have a lacrimal sac fossa bounded by thicker maxillary bone, this bone constituting a higher proportion of the fossa wall at its midpoint, and also have significantly less nasal mucosa available for soft-tissue anastomosis during lacrimal drainage surgery. The anterior lacrimal crest, comprising the frontal process of the maxilla, was thickest at the lowest plane in both black Africans and Caucasians.

Anatomical landmarks of the lateral nasal wall: implications for endonasal lacrimal surgery

PURPOSE OF REVIEW

An accurate understanding of the anatomy of the lateral nasal wall is key to achieving complete exposure of the lacrimal sac during endonasal dacryocystorhinostomy (EnDCR) and the avoidance of complications such as basal skull fracture and orbital fat prolapse. This review provides a comprehensive summary of the clinical and cadaveric anatomical studies of the lateral nasal wall to date and their application to endonasal lacrimal surgery.

RECENT FINDINGS

The maxillary line and the axilla of the middle turbinate are the major landmarks commonly utilized by lacrimal surgeons to localize the lacrimal sac. Numerous clinical, cadaveric and radiologic studies have attempted to define the relationship of these and other important anatomical landmarks, closely related to the lacrimal sac and routinely encountered during endonasal surgery, such as the frontal process of the maxilla, the agger nasi air cell and the uncinate process. A greater understanding of the relevant endonasal anatomy over time has led to safer and more effective surgical techniques.

SUMMARY

Greater insights into the precise anatomical relationship of the lacrimal sac to other structures on the lateral nasal wall has enabled lacrimal surgeons to perform EnDCR surgery in a more accurate, efficient and well tolerated manner, matching its success to that of the external approach.

Surgical and topographic anatomy of the maxillary line: an important landmark for endoscopic nasal surgery

The maxillary line is an important surgical landmark in the lateral nasal cavity. We investigated its location, variation, and relation to other landmarks in 47 formalin fixed cadaveric half-heads dissected in steps. Measurements and observations were made to describe the topography of the maxillary line, maxillary line midpoint (M-point), and their relationship with surgically important structures. The mean curved length of the maxillary line was 15 mm (SD 3.5) and can be classified into three types. The M-point had a mean vertical distance of 0.8mm (SD 2.9) below the nasolacrimal sac-duct junction. It was found below, above, or on the same level as the nasolacrimal sac-duct junction in 57.4%, 38.3%, and 4.3% of specimens, respectively. In 51.1% the M-point was anterior to the nasolacrimal duct axis and 48.9% overlapping the lacrimal apparatus. The maxillary line and its M-point are useful surgical landmarks for localizing the nasolacrimal duct segments.