Relação anatômica do nervo óptico com o seio esfenoidal: estudo por tomografia computadorizada

Evaluation of variations of optic nerve course in relation to posterior paranasal sinuses in MDCT in a tertiary care center of Nepal: a retrospective cross-section study

Background

The proximity of optic nerves to the posterior paranasal sinuses (PNS) is a critical consideration in preventing optic nerve injuries during functional endoscopic sinus surgery.

Methods

A retrospective cross-sectional study was conducted on 367 patients aged 13 years and above. Four radiologists, each with 2-6 years of experience, evaluated computed tomography scans of the PNS and the head of these patients. The optic nerves were classified into four types based on DeLano's classification, and their respective prevalence rates were determined. Additionally, the prevalence of optic nerve dehiscence and pneumatization of the anterior clinoid process was assessed.

Results

A total of 734 optic nerves were evaluated and categorized into four groups as per DeLano's classification. The most common type was classified as type 1 optic nerve, representing 65.4% of all optic nerves. Types 2, 3, and 4 optic nerves accounted for 16.9, 8.6, and 9.1%, respectively. The prevalence rates of type 1, type 2, type 3, and type 4 optic nerves were 76.6, 24.5, 12.3, and 14.4%, respectively. Optic nerve dehiscence was observed in 14.3% of cases, with a prevalence of 21.2% in the study. Type 3 optic nerves were most commonly associated with dehiscence, with 49.2% of them showing dehiscence in their course through the ethmoid or sphenoid sinus. The prevalence of pneumatization of the anterior clinoid process in the study population was 28.3%, with type 3 optic nerves being the most frequently associated.

Conclusion

An understanding of the relationship between optic nerves and posterior PNS, as well as awareness of optic nerve dehiscence, is essential in preventing injuries during sinus surgeries. Type 1 optic nerve predominates among Nepalese patients visiting our hospital.

Inter Observer Agreement Among Radiologist and Otorhinolaryngologists on Paranasal Sinus Computed Tomography Scans in Chronic Rhinosinusitis

To evaluate inter observer agreement between Radiologist and Otorhinolaryngologists in identifying important structures and pathologies on pre operative computed tomography (CT) scans of paranasal sinus (PNS) in chronic rhinosinusitis (CRS). A retrospective review of CT scans PNS of CRS patients. Archived CT scans were evaluated by 3 observers, similarly experienced radiologist and otorhinolaryngologist and a less experienced otorhinolarygologist. The degree of intra- as well as inter observer agreement was assessed by Cohen's kappa statistics. A moderate and a fair inter observer agreement was noted among experienced radiologist and otorhinolaryngologist; & experienced experts and less experienced otorhinolaryngologist respectively. The greatest disagreements among all observers were found in superior attachment of uncinate process, optic nerve's relationship with sphenoid sinus and dehiscence of anterior ethmoid canal. The present study demonstrated a considerable inter observer variability among radiologists and otorhinolaryngologists, irrespective of their experience in the field of speciality. A few critically important structures which showed an unsatisfactory level of agreement and thus need to be sought after with more training and practice, were also identified. These included Keros type, optic nerve's location, dehiscence of anterior ethmoid artery, vidian and maxillary nerves, lamina papyracia defect, sphenoid sinus pneumatization and attachment of uncinate process. The study also emphasized the importance of inter disciplinary conferences for pre operative evaluation of sinus CT scans of CRS patients.

Is There Any Racial Difference in Term of Anatomical Variations of Nasal and Paranasal Sinus Structures

The aim of our study was to determine the anatomical variations detected on computed tomography radiological imaging of the paranasal sinus between citizens and refugees patient groups and to reveal the differences between the two patient groups. In this study, the data from the files of 38 Turkish Citizens (Group 1), 41 Syrian Refugees (Group 2), a total of 79 patients who were admitted to the ENT Clinic of Adana City Training and Research Hospital due to rhinological complaints between 01.01.2019 and 01.01.2020 and had paranasal sinus tomography, were analyzed retrospectively. Due to the Syrian Civil War that started in 2011, more than 10 million Syrian have left their countries and immigrated to neighboring countries as refugees. The paranasal sinus area has a wide variety of variations. Congenital anomalies and normal anatomical variations in this area are important, although rarely, as they may have pathological consequences or may be a source of difficulty during surgery. In the study, 38 of 79 patients were in Group 1 (48.1%) and 41 were in Group 2 (51.9%). Of the patients, 30 were female (38%) and 49 were male (62%). The ages of the patients ranged from 9 to 78 years, with a mean age of 32.52 years. In our study, we could not find a statistically significant difference between Turkish Citizens and Syrian refugees in terms of anatomical variations detected on paranasal radiological imaging. We consider the number of patients in our study as a limitation of our study and we think that it is important to conduct studies with larger populations.

Volumetric and linear evaluation of the sphenoidal sinus of a Brazilian population, in cone beam computed tomography

The determination of sex from skeletal remains has been widely used in biological profile reconstruction since these are some of the last structures to perish after death. The sphenoid sinus is located deeply in the skull and is enveloped by diverse structures within the sphenoid body. It is, therefore, less predisposed to injuries and/or pathological changes. The aim of this study is to evaluate the possibility of determining sex in a Brazilian population by means of linear and volumetric measurements of the sphenoid sinus, in addition to identifying and quantifying the presence of extensions of this sinus in cone beam computed tomography (CBCT) scans. In total 268 CBCT scans were analysed, from patients aged between 22 and 70 years old, of which 145 were female, and 123 were male. The images, representative of a Brazilian population, were selected by a dental radiologist from a CBCT image bank. The volumetric measurements were made by means of the segmentation software ITK-SNAP 3.0® and the linear inferio-superior, latero-lateral and anteroposterior measurements, as well as the presence of extensions of the sphenoidal sinus, were made using the CS Imaging Software®. The results of this study suggested that when comparing men and women, there were no statistical differences in the linear measurements and extensions of the sphenoidal sinus, although the values were considerable in the extensions for the pterygoid processes and greater wings of the sphenoid bone, particularly in women. However, there was a statistically significant difference when the sphenoidal sinus volume was compared, as it was larger for men (11.364 mm³ ± 4.229 mm³) than for women (10.000 mm³ ± 3.615 mm³). In summary, the sphenoidal sinus volumetric measurements in CBCT exams are useful for determining the sex of unknown individuals.

Endonasal identification of the orbital apex

OBJECTIVES/HYPOTHESIS

To describe anatomical landmarks for endoscopic endonasal approaches to the orbital apex and to measure the distances between those landmarks.

METHODS

In this anatomic study, the nasal fossae of 30 adult fresh cadavers were dissected (n = 60 half-skulls). One double-injected orbit was carefully dissected, mainly focusing on the neurovascular structures. The orbital apex was dissected under endoscopic endonasal visualization in all cases. The distances between the ethmoidal crest and choanal arch to the optic canal (OC) and superior orbital fissure (SOF) were measured and recorded.

RESULTS

The sample was predominantly male (63.3%, 19/30 cadavers). The following correlations between measurements according to side were observed: ethmoidal crest to OC, r = 0.748 (P = 0.0001); ethmoidal crest to SOF, r = 0.785 (P = 0.0001); choanal arch to OC, r = 0.835 (P = 0.0001); choanal arch to SOF, r = 0.820 (P = 0.0001).

CONCLUSIONS

In the cadavers studied in this sample, the ethmoidal crest and choanal arch were relevant structures and exhibited consistent measurements. Spearman correlation coefficients were greater than 0.7, which is indicative of good correlation between measurements obtained in the skull halves of each cadaver. Comparison of the measurements obtained in different sides showed similar values, with no statistically significant differences in the distances between any of the proposed anatomic landmarks.