Anatomical Study of the Intraosseous Pathway of the Infraorbital Nerve

Maxillary Sinus Anatomy and Physiology

This study summaries the anatomy, including neurovascular anatomy, and physiology of the maxillary sinus. As the maxillary sinus is intimately related to the maxillary dentition, the maxillary sinus is the first paranasal sinus to become involved in infections of dental origin. Not only are these infections often very symptomatic but also spread to neighboring paranasal sinuses and extrasinus tissues such as the skin and the orbit.

Location of infraorbital and accessory infraorbital foramina in Iranian population: a retrospective radiological study with crucial clinical implications

PURPOS

The location of infraorbital foramen (IOF) and the prevalence of accessory IOF vary among different populations. It may lead to infraorbital nerve (ION) blockage during surgery. This study aimed to assess the IOF location and AIOF frequency in Iranian people.

METHOD

In this retrospective cross-sectional study, 500 paranasal sinus computed tomography scans of adults were examined using the INFINITT PACS system.

RESULT

The distance from IOF to infraorbital margin (IOM), mid-pupillary line (MPL), midsagittal line (MSL), canine eminence (CE), and skin thickness (ST) was 8.97 ± 1.79, 5.73 ± 1.84, 24.86 ± 2.23, 20.39 ± 3.47, and 10.90 ± 2.59 mm, respectively. The vertical and transverse diameters of the foramen were 3.03 ± 0.65 and 3.71 ± 0.76 mm, respectively. In addition, the shape of 63.5% of the foramina was oval. The prevalence of AIOF was 9%, and its most common location was superomedial to IOF.

CONCLUSION

We believe that in this study, landmarks like IOM, MPL, MSL, CE and ST could help the clinicians localize IOF and improve the ION anesthesia success rate. Furthermore, the occurrence of AIOF should be considered by physicians to reduce the chance of injuries to the infraorbital neurovascular complex.

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.

A morphological study and the variability in the number of infraorbital foramina in the African green monkey (Grivet) (Chlorocebus aethiops) using microcomputed tomography

Knowledge of the nonhuman primate morphology and anatomy related to craniofacial mechanoreception is essential for a fundamental understanding of the incidents that have occurred during the evolution of craniofacial features. The present study focuses on the variability in the number of infraorbital foramina and associated anatomical structures such as the infraorbital canal (IOC) and the infraorbital groove (IOG), as they are considered to play an important role in the behavioral ecology of these animals. A total of 19 skulls of Chlorocebus aethiops were analyzed. The number of infraorbital foramina was assessed macroscopically using a magnifying glass and a small diameter probe. Three dimensional (3D) projections and morphometric analysis of the infraorbital foramina, IOCs, and IOGs were performed using microcomputed tomography (micro-CT) for two skulls that represent one of the most common morphological types. Regardless of sex and body side, the most common morphological type observed in the studied species is the presence of three infraorbital foramina. The IOC takes a funnel or pinched shape. 3D projections were made to assess the course of the infraorbital vascular and nerve bundles in selected individuals. The results indicate a high morphological diversity within the species, although there appears to be a consistent distribution pattern of infraorbital neurovascular bundles in species of the Cercopithecidae family. The use of X-ray micro-CT allowed 3D visualization of the maxillary region to determine the variability of the infraorbital foramina and to track the division of the infraorbital neurovascular bundle in the case of the most common macroscopic expression of the number of the infraorbital foramen in C. aethiops, as well as the morphometric of the IOCs and IOGs which are related to mechanoreception of the primate's snout.

Morphological and Morphometric Relations of Infraorbital Foramen in North Indian Population

Introduction The evidence regarding the anatomy of the infraorbital foramen in the Indian population is limited. It mainly focuses on its shape, size, and incidence in the Indian population. The current study aimed to evaluate morphometric parameters of infraorbital foramen that can help clinicians during surgery and procedures around it. Methods We evaluated 90 dry adult human hemi-skulls. The morphological parameters studied included the assessment of the shape of the infraorbital foramen, its horizontal and vertical diameters, and its relation to the teeth of the upper jaw. In addition, we measured the distance of the infraorbital foramen from the anterior nasal spine, nasion, infraorbital margin, and the lower extent of the alveolar margin. The length of the infraorbital canal till the inferior orbital fissure and the infraorbital groove and the infraorbital canal orientation angles in different planes were also measured. The measurement values were compared between the right and left side hemi-skulls. Results The oval-shaped infraorbital foramen was most commonly noticed. The mean vertical and transverse diameters were 3.8 mm and 2.6 mm, respectively, on the right side. The left side's mean vertical and transverse diameters were 3.9 mm and 2.5 mm, respectively. The most common location of infraorbital foramen was in line with the maxillary second premolar tooth. The distances of infraorbital foramen from the alveolar margin were 29.6 mm and 29 mm on the right and left sides, respectively. The distances of the infraorbital foramen from the anterior nasal spine were 34.3 mm and 34.2 mm on the right and left sides, respectively. The distances of infraorbital foramen from the nasion were 42.3 mm and 42.2 mm on the right and left sides, respectively. The distances of infraorbital foramen from the inferior orbital margin were 5.8 mm and 6.2 mm on the right and left sides, respectively. The distances between the inferior orbital margin and infraorbital groove were 12.7 mm and 12.7 mm on the right and left sides, respectively. The distances between the inferior orbital margin and inferior orbital fissure were 27.5 mm and 27.1 mm on the right and left sides, respectively. The orientation angles of infraorbital foramen were 48.31° in the horizontal plane, 34.07° in the Frankfurt plane, and 14.4° in the parasagittal plane. Conclusion Our findings suggest that the location of the infraorbital foramen is difficult to standardize, considering the wide interindividual variations in the foramen relations. Further research should be performed to investigate the parameters related to the distance and orientation of the infraorbital foramen in relation to nearby bony landmarks that are least affected by individual variations in skull morphology.

Cone beam computed tomographic evaluation of infraorbital canal protrusion into the maxillary sinus and its importance for endoscopic surgery

OBJECTIVE

The aim of this retrospective study is to investigate the prevalence of Infraorbital Canal Protrusion (ICP) degree into the maxillary sinus and its relationship with variations in adjacent structures on Cone Beam Computed Tomography (CBCT) images.

METHODS

350 CBCT images (700 Infraorbital Canal [IC]) were evaluated retrospectively. ICP was divided into 3 subtypes according to the protrusion degree. The correlation between IC types and variations in adjacent anatomical structures (Haller cell, middle nasal concha pneumatization, maxillary sinus mucosal thickening and septa) was evaluated. The distance between Infraorbital Canal and Cnine Root (IC-CR) was also measured. For type 3, measurements were performed on IC as the length of the bony septum from the IC to the Mxillary Sinus Wall (IC-MSW), the distance from the inferior orbital rim, where the IC begins to protrude into the maxillary sinus (IOR-ICP), the vertical distance from the IC to the Maxillary Sinus Roof (IC-MSR) and Floor (IC-MSF).

RESULTS

The prevalence of type 1, 2 and 3 was 62.9%, 29.1%, and 8% respectively. IC-CR was 10.2, 10.7 and 11.4 mm in type 1, 2 and 3, respectively. IC-MSW, IOR-ICP, IC-MSR and floor IC-MSF was 3.8, 10.9, 7.4 and 27.7 mm, respectively. On the right and left side, statistically significant correlation was found between IC types and the presence of the Haller cell and sinus septa. But there was no significant correlation between IC types and middle concha pneumatization.

CONCLUSION

Accurate diagnosis of ICP is very important in preventing infraorbital nerve damage in surgical procedures to be performed in the maxillary region. The results of this study could be a guide for surgical planning in this region.

LEVEL OF EVIDENCE

Retrospective study.

Prevalence of canalis sinuosus and accessory canals of canalis sinuosus on cone beam computed tomography: a systematic review and meta-analysis

The aim of this systematic review was to determine the prevalence of the canalis sinuosus (CS) and accessory canals of the canalis sinuosus (ACCS) as identified on cone beam computed tomography (CBCT). Online searches were conducted in the MEDLINE (via PubMed), Scopus, LILACS, Cochrane CENTRAL, Web of Science, and SIGLE (via OpenGrey) databases. Primary studies that determined the prevalence of canalis sinuosus and/or its anatomical variations using CBCT were included. The risk of bias assessment was performed using the AQUA tool. The quality effects model using double arcsine transformation was used for the meta-analysis of prevalence. Heterogeneity, publication bias, and sensitivity analyses were performed. Of 3237 initial results, 17 papers were included for systematic review. The meta-analysis comprising 1994 patients showed a pooled prevalence of CS of 0.80 (95% confidence interval (CI) 0.51-0.99; P = 0.001; I² = 99%). Publication bias analysis revealed minor asymmetry (LFK index 1.84). The meta-analysis of 4605 patients showed a pooled prevalence of ACCS of 0.54 (95% CI 0.38-0.69; P = 0.001; I² = 99%). The sensitivity analysis showed a pooled prevalence of ACCS of 0.53 (95% CI 0.32-0.74; P = 0.001; I² = 99%) for studies with ≥ 1000 patients and 0.55 (95% CI 0.33-0.76; P = 0.001; I² = 98%) for studies with< 1000 patients. Canalis sinuosus showed a pooled prevalence of 0.80 and ACCS showed a pooled prevalence of 0.54; hence both should be considered as anatomical structures, which means that they are present in most people. Surgeons must be aware of the CS and ACCS on CBCT analysis during pre-surgical planning. PROSPERO REGISTRATION NUMBER: CRD42020154195.

[Surgical anatomy of the maxillary sinus]

BACKGROUND

Improved understanding of the microanatomy of the paranasal sinuses, including its individual variations, makes a substantial contribution to current progress in endonasal endoscopic microsurgery. Microanatomy of the sinuses is an active field of present scientific investitations.

MATERIALS AND METHODS

A comprehensive review on microanatomy of the maxillary sinus is presented from the perspective of contemporary endonasal endoscopic microsurgery.

RESULTS

The range of variation of the individual microanatomy of all sections of the maxillary sinus is presented, in particular to minimize secondary sugical tissue trauma, to avoid complications (e.g. on orbital tissues) and as a basis for the prelacrimal access to the maxillary sinus.

CONCLUSION

Improved understanding of the range of microanatomical variations reduced the burden on the patient while opimizing the effectiveness of the necessary surgical manipulations.

Value of Performing Routine Vascular Mapping Synchronous with Radiographic Assessment of Endodontic Lesions: Case Series

With the adoption of limited-volume cone beam computed tomographic (CBCT) imaging in dentistry, high resolution of the maxillomandibular complex has led to the recognition of numerous accessory neurovascular canals. The preoperative identification of these structures is essential to facilitate the safe performance of an assortment of invasive dental procedures; however, there is limited information in the endodontic literature regarding mapping of these neurovascular canals and their anatomic variants. To emphasize the utility of accessory neurovascular channel mapping in conjunction with endodontic therapy, we have presented the clinical findings of 4 diverse cases. Comprehensive evaluation of the CBCT scans showed relevant underlying etiopathologies, prompting clinical modifications that led to enhanced patient outcomes.

Variability in the number of infraorbital foramina in rhesus macaques (Macaca mulatta) and cynomolgus macaques (Macaca fascicularis)

This study aimed to determine the number of infraorbital foramina in monkeys of the Papionini tribe. The authors performed a μCT analysis of the morphology of the infraorbital foramina. A total number of 52 simian skulls belonged to two macaque species: Macaca mulatta and Macaca fascicularis were used in the study. The number of infraorbital foramina was counted macroscopically and with the use of a magnifying glass. Next, the skull representing the most common morphological type was selected and scanned by micro-computed tomography (μCT). The Shapiro-Wilk normality test was used in the study. To compare the differences in the number of infraorbital foramen between species, sex and sides, the Mann-Whitney U test was applied. Three infraorbital foramina were present in most individuals from the test group. The Mann-Whitney test revealed no statistically significant difference between the number of foramina on the right- and left-hand side. Likewise, no statistically significant differences between the numbers of infraorbital foramina across sexes were observed. Volumetric reconstructions revealed the presence of separate infraorbital canals for each infraorbital foramen. Craniofacial innervation in macaques is formed by complex branching patterns of cranial nerves. Variability in the number of infraorbital foramina suggests a variable maxillary innervation pattern in these animals. Based on the analysis of volumetric projections, the presence of two labial branches and a single nasal branch of the infraorbital nerve is suggested. Detailed descriptions are supported by quantitative data and μCT evidence.

The maxillary sinus: physiology, development and imaging anatomy

OBJECTIVES

The maxillary sinus is of paramount importance for otolaryngologists, rhinologists, oral and maxillofacial surgeons, head and neck and dental and maxillofacial radiologists. A comprehensive review article concerning the physiology, development and imaging anatomy was undertaken.

METHODS

Relevant literature pertaining to the physiology of the sinonasal cavity, development of the paranasal sinuses and imaging anatomy of the maxilla and maxillary sinus from 2000 to 2019 was reviewed. Emphasis was placed on literature from the last 5 years.

RESULTS

Extensive recent research using imaging has provided new insights into the development of the maxillary sinus, the other paranasal sinuses and the midface. The fundamental physiological concept of mucociliary clearance and its role in sinus health is emphasized. The paranasal sinuses are an integral part of a common mucosal organ formed by the upper and lower airway.An in-depth understanding of the soft-tissue and neurovascular relationships of the maxillary sinus to the deep fascial spaces and branches of the trigeminal nerve and external carotid artery respectively is required to evaluate and report imaging involving the maxillary sinus.Sinusitis of rhinogenic, rather than odontogenic origin, originates from nasal inflammation followed by anterior ethmoid disease and secondary obstruction of the ostiomeatal unit. The role of anatomical variants that predispose to this pattern of disease is discussed in detail with illustrative examples.The maxillary sinus is intimately related to the roots of the posterior maxillary teeth; the high frequency of mucosal disease and sinusitis of odontogenic aetiology is now well recognized. In addition, an understanding of the anatomy of the alveolar process, morphology of the alveolar recess of the maxillary sinus and neurovascular supply are essential both for deliberate surgical intervention of the sinus and complications related to oral surgical procedures.

CONCLUSIONS

An understanding of the fundamental principles of the development, physiology, anatomy and relationships of the maxillary sinus as depicted by multi-modality imaging is essential for radiologists reporting imaging involving the paranasal sinuses and midface.

The Appearance of The Infraorbital Canal and Infraorbital Ethmoid (Haller's) Cells on Panoramic Radiography of Edentulous Patients

Objectives. The aim of the study is to detect the prevalence and the characteristics of infraorbital canal and Haller's cells on panoramic radiography of edentulous patients. Methods. The study group comprised 291 panoramic radiographs of edentulous patients. Radiographs were interpreted for the visibility and characteristics of infraorbital canal and Haller's cells. For classification of infraorbital canal, a method based on the image characteristics of the border of the canal (Types I, II, and III) was used. Haller's cells were grouped according to the number and the shape of loculations. Results. Infraorbital canal was observed in 246 (84.6%) radiographs. The most prevalent of the observed canals were Type III for both sides (39.9 % for right and 32.3% for left side). The visibility of Haller's cells was 23.7%. The frequencies of Haller's cells' visibility were approximately equal for both genders. There is no significant difference between genders for the visibility of infraorbital canal and Haller's cells. Conclusions. The surgeons, implantologists, and radiologists should take into consideration infraorbital canal and Haller's cell for planning implant surgery of maxillary anterior region and undefined orofacial pain for edentulous patients.