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

Infraorbital canal variants and its clinical and surgical implications. A systematic review

BACKGROUND

Recent literature highlights anomalous cranial nerves in the sinonasal region, notably in the sphenoid and maxillary sinuses, linked to anatomical factors. However, data on the suspended infraorbital canal (IOC) variant is scarce in cross-sectional imaging. Anatomical variations in the sphenoid sinuses, including optic, maxillary, and vidian nerves, raise interest among specialists involved in advanced sinonasal procedures. The infraorbital nerve's (ION) course along the orbital floor and its abnormal positioning within the orbital and maxillary sinus region pose risks of iatrogenic complications. A comprehensive radiological assessment is crucial before sinonasal surgeries. Cone-beam computed tomography (CBCT) is preferred for its spatial resolution and reduced radiation exposure.

OBJECTIVE

The aim of this study was to describe the prevalence of anatomical variants of the infraorbital canal (IOC) and report its association with clinical condition or surgical implication.

METHODS

We searched Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception up to June 2023. Two authors independently performed the search, study selection, data extraction, and assessed the methodological quality with assurance tool for anatomical studies (AQUA). Finally, the pooled prevalence was estimated using a random effects model.

RESULTS

Preliminary results show that three types are prevalent, type 1: the IOC does not bulge into the maxillary sinus (MS); therefore, the infraorbital foramen through the anterior wall of MS could be used for identification of the ION. Type 2: the IOC divided the orbital floor into medial and lateral aspects. Type 3: the IOC hangs in the MS and the entire orbital floor lying above the IOC. From which the clinical implications where mainly surgical, in type 1 the infraorbital foramen through the anterior wall of MS could be used for identification of the ION, while in type 2, since the lateral orbital floor could not be directly accessed an inferiorly transposition of ION is helpful to expose the lateral orbital wall directly with a 0 scope; or using angled endoscopes and instruments, however, the authors opinion is that direct exposure potentially facilitates the visualization and management in complex situations such as residual or recurrent mass, foreign body, and fracture located at the lateral aspect of the canal. Lastly, in type 3, the ION it's easily exposed with a 0° scope.

CONCLUSIONS

This systematic review identified four IOC variants: Type 1, within or below the MS roof; Type 2, partially protruding into the sinus; Type 3, fully protruding into the sinus or suspended from the roof; and Type 4, in the orbital floor. Clinical recommendations aim to prevent nerve injuries and enhance preoperative assessments. However, the lack of consistent statistical methods limits robust associations between IOC variants and clinical outcomes. Data heterogeneity and the absence of standardized reporting impede meta-analysis. Future research should prioritize detailed reporting, objective measurements, and statistical approaches for a comprehensive understanding of IOC variants and their clinical implications. Open Science Framework (OSF): https://doi.org/10.17605/OSF.IO/UGYFZ .

Protrusion of the infraorbital canal into the maxillary sinus: A cross-sectional study in Cairo, Egypt

Purpose

The aim of this study was to investigate the prevalence of infraorbital canal protrusion in an Egyptian subpopulation using cone-beam computed tomography and to describe its radiographic representation.

Materials and Methods

This retrospective cross-sectional study was conducted using the records of 77 patients and 123 maxillary sinuses. The full lengths of the sinuses were visible for the detection of infraorbital canal protrusion. The infraorbital canals were classified into 3 types based on their relation to the sinus. If the septum was present, its length and its distance from the sinus floor were measured. Qualitative and quantitative variables were described as percentages and means with standard deviations, respectively.

Results

The infraorbital canal most commonly presented as the normal confined type (detected in 78.1% of sinuses), whereas the suspended (or protruded) variant was found in 14.6% of the examined sinuses. The septal length ranged from 0.9 to 5.1 mm, with a mean of 2.8±1.1 mm. The distance to the sinus floor ranged from 5.2 to 29.6 mm depending on the sinus shape and size.

Conclusion

The present study indicates that protrusion of the infraorbital canal is not rare, and surgeons that use the maxillary sinuses as corridors for their procedures must be more cautious, especially in the upper lateral confines of the sinus.

Infected Haller Cell Misdiagnosed as Invasive Fungal Sinusitis - A Parallax

We report an unusual case of a 29-year-old female with a short duration of right lower eyelid swelling, painful eye movement and paraesthesia of right cheek. She was subsequently worked up with mucormycosis in mind, but intra-operative findings were suggestive of an infected Haller cell and post-operatively she was symptom free.

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.

Air spaces neighbouring the infraorbital canal

OBJECTIVE

The infraorbital canal (IOC) courses through the roof of the maxillary sinus (MS). Different grading systems concerning the topography of the IOC have been proposed. Further, it has been suggested that a transantral IOC would be morphologically related to Haller's cells (HCs). However, we hypothesized that this is not necessarily the case. Hence, we aimed to study the anatomical possibilities of the air spaces located medially to the IOC.

MATERIALS AND METHODS

The cone-beam computed tomography (CBCT) files of 40 adult patients were retrospectively evaluated.

RESULTS

The transantral type of IOC was found in 32.5% of patients. The infraorbital recesses of the MS were found medial to the IOC in 20% of patients. As referred to the nasolacrimal canal, these recesses were either prelacrimal (appearing as false isolated air cells) or retrolacrimal (appearing as false HCs). True HCs were found in 10% of patients. They were located medial to the IOC and they drained into the ethmoidal infundibulum (EI), which was distinct from the MS drainage. In 15% of patients, aerated nasolacrimal ducts (NLDs) were found anterior to the EI and medial to the antral angle. They were capable of masquerading either a HC or an infraorbital recess of the MS.

CONCLUSION

Previous classifications of the IOC, which related it to HCs, were reviewed and the evidence was found to be insufficient to assess the HC-related topography of the IOC. Therefore, to achieve the accurate anatomical identification of the air spaces neighbouring the IOC, the infraorbital recesses of the MS, the HCs, and the aerated NLDs should be carefully discriminated within the antero-supero-medial antral angle.