Computed tomographic analysis of frontal sinus drainage pathway variations and frontal rhinosinusitis

Relationship between the Superior Attachment of the Uncinate Process and Pneumatization of the Middle Turbinate—A Radiological Study

Objective: the superior attachment of the uncinate process (SAUP) is highly variable. Lateral types of SAUP are associated with frontal rhinosinusitis. SAUP in the middle turbinate is more common when the middle turbinate is aerated. We aim to refine these findings by studying the relationship between the SAUP type and the different subtypes of pneumatization of the middle turbinate. Methods: 200 CT sinonasal scans were analyzed by an otolaryngologist and a radiologist. All CT scans were analyzed to study the type of the middle turbinate concha bullosa and lamellar cell and the type of SAUP. Results: 379 sides were analyzed. The prevalence of the various types of SAUP were: Type I: 43.80%, Type II: 22.16%, Type III: 16.36%, Type IV: 3.69%, Type V: 9.76%, and Type VI: 4.22%. When studying the pneumatization of the middle turbinate and the SAUP types, we only found a statistically significant association between the lateral attachment of the uncinate process and the presence of a lamellar cell (p = 0.029). Conclusion: lateral types of SAUP are more likely in the presence of a lamellar cell. This finding, therefore, renders checking for lateral SAUP types in the presence of a lamellar cell even more relevant than when studying the pre-surgical CT scan. In those cases, it is advisable to perform a careful and complete uncinectomy.

N, Hosemann W. Supplements and refinements to current classifications and nomenclature of the fronto-ethmoidal transition region by systematic analysis with 3D CT microanatomy

Objective: The microanatomy of the fronto-ethmoidal transition region has been addressed in several classifications. CT stereoscopic imaging (3DCTSI) provides improved display and delineates three defined complex “spaces”, the Frontal Sinus/Frontal Recess Space, the Infundibular Space of the Ethmoid Uncinate Process, and the Ethmoid Bulla Space (FSRS, IS-EUP, EB), none of which were adequately described with the “cell” terminology. We present details on the 3D microanatomy, variability, and prevalence of these spaces. Methods: 3D stereoscopic imaging displays (3DCTSI) were created from 200 datasets. The images were analyzed and categorized by a radiologist (SJZ), and consultant otolaryngologists, focusing on 3D microanatomy of the fronto-ethmoidal transition, the frontal recess/frontal sinus, and drainage pathways, in comparison to established anatomical classification systems. Results: The anterior ethmoid is subdivided into seven groups with the following core properties and prevalence: 1. The horizontal roof of the IS-EUP is attached to the superior half of the frontal process of the maxilla (19%); 2. The IS-EUP extends into the frontal recess (6.5%); 3. The IS-EUP extends into the frontal recess and the frontal sinus (18.5%); 4. A bulla is seen in the medial frontal sinus (3%); 5. The ethmoid bulla and supra bullar space extend into the frontal sinus (7%); 6. Lamellae extend into the FSRS antero-superiorly (25%); 7. FSRS expansion expands below the upper half of the frontal process of the maxilla (FSRS) (21%). Conclusion: 3-D analysis of the detailed anatomy provides important new anatomic information with the increased focus on precision surgery in the region.

Association between the insertion type of the uncinate process and the development of Frontal Sinus Mucoceles - is there a relationship?

BACKGROUND

The frontal sinus drainage pathway is formed by either the ethmoid infundibulum or the middle meatus, which depends on the superior insertion of the uncinate process. According to Landsberg & Friedman the are 6 types of superior uncinate process insertion. The aim of this study is to find an association between the uncinate process insertion type and the development of frontal sinus mucoceles.

METHODS

Fifty sinus CT scans were analysed. Exclusion criteria were previous nasal surgeries, malignancy, polyposis and an insufficient image quality. Superior insertions of the uncinate process were analysed according to the Landsberg & Friedman classification. The results were tabulated and analysed using SPSS 25.0.

RESULTS

The analysis revealed type 1 insertion in 6% of the CT scans, type 2 in 32%, type 3 in 26%, type 4 in 0%, type 5 in 28% and type 6 in 8%. Despite 44% of the CT scans with frontal sinus mucocele showing a type 2 insertion of the uncinate process, both the Chi-Square test and the Cramer's V test showed no statistical significance (p>.05). Logistic regression also showed that uncinate process insertion type does not influence the likelihood of development of frontal sinuses mucoceles.

CONCLUSIONS

The insertion of the uncinate process does not influence the development of frontal sinus mucoceles.

Endoscopic frontal recess anatomy directed by the drainage pathways using the connecting plates as landmarks

PURPOSE

To investigate the anatomical features of frontal recess (FR) drainage, and the classification of FR cells and frontal sinus (FS).

METHODS

Fifty sides from 30 adult cadaver heads were examined. FR cells and FS along the drainage pathways were dissected under 0° and 70° endoscopic views using unique connecting structures between the uncinate process and the ethmoid bulla as landmarks.

RESULTS

Connecting plates between the uncinate process and the ethmoid bulla were discovered and termed medial suprainfundibular plate (MSIP), which were observed on each cadaver head, and lateral suprainfundibular plate (LSIP) on 92% (46/50) sides. Separated by MSIP, two drainage pathways were identified and named medial pathways of the FR (MPFR) medial to the MSIP and the lateral pathways of the FR (LPFR) in the lateral side. Different drainage pathways of the FS were confirmed, in which drained into the MPFR in 37 and into the LPFR in 13 of the cadaver sides.

CONCLUSIONS

MSIP is the critical landmark for the recognition of MPFR, LPFR, and the classification of FR cells. The FR resection along LPFR and MPFR facilitated excellent exposure of FS.

Sinus Irrigation Penetration After Proposed Modified Draf IIa Technique in a Side-to-Side Cadaveric Model

BACKGROUND

Endoscopic sinus surgery (ESS) is an effective intervention for patients with medically refractory chronic rhinosinusitis. Frontal sinusotomy is the most challenging part of ESS, with one of the key outcomes being access for topical irrigations.

OBJECTIVE

The purpose of this study is to compare irrigation penetration into the frontal sinus following Draf IIa versus modified Draf IIa frontal sinusotomy.

METHODS

Four fresh cadaver heads were used in this experiment. Draf IIa was performed on one side of each head and a modified Draf IIa on the contralateral side. This proposed modification consists of a Draf IIa combined with an agger nasi punch-out procedure and partial trimming of the vertical lamella of the middle turbinate back to the posterior table of the frontal sinus without drilling the beak. Each head was irrigated with methylene blue-dyed water and recorded by rigid endoscopy through an endonasal view (EV) of the frontal sinus and frontal trephination view (TV). Two blinded rhinologists scored the extent of staining (using an ordinal scale of 0 to 3) for each side. A case report where the modified Draf IIa was performed is also described.

RESULTS

After modified Draf IIa sinuosotomy, the mean score for the EV was 2.125 and for the TV was 2, versus 0.875 and 0.625 for traditional Draf IIa, respectively. There was a statistically significant increase for both EV (p = 0.019) and TV (p = 0.018) after modified Draf IIa.

CONCLUSION

In our cadaveric model, this procedural modification improved penetration of postoperative irrigations into the frontal sinus. This simple technique may be easily adapted into frontal ESS when indicated.

Can Volumetric and Morphological Variants of Sphenoid Sinuses Influence Sinuses Opacification?

Improvements in computed tomography and in functional endoscopic sinus surgery have recently increased interest toward paranasal sinus anatomy and anatomic variations that can be observed in patients affected by sinusitis. Isolated sphenoid sinusitis is a relatively rare pathology, often related to nonspecific symptoms, therefore making diagnosis difficult. The correlation between this type of sinusitis and anatomical variants remains unclear.The authors' aim was to retrospectively revise paranasal sinuses computed tomography scans of patients affected by sphenoid sinusitis, compared with a control group, analyzing the types of sphenoid sinus and the presence of aberrant pneumatization, and performing a segmentation of the sphenoid sinuses to calculate the volumes.Sphenoid sinuses of 60 patients affected by sinus opacification, compared with a control group, were segmented. Type of sinus (sellar, presellar, postsellar) and presence of aberrant pneumatization were assessed as well. Possible statistically significant differences in volumes according to sex and group were assessed through 2-way ANOVA test (P < 0.05). Post-hoc test was assessed through Student t test. χ test was applied in order to verify the statistically significance of differences in frequency of different types of sinus pneumatization variants (P < 0.05).Average volume of sphenoid sinuses in males was of 7.672 cm and of 7.751 cm in females within the group of patients; statistically significant differences in volume were found according to sex (P: 0.342), but not between the patients and control group (P: 0.0929). Post-hoc test verified that males affected by sinus opacification showed smaller volumes in comparison with the control males (P < 0.05). In addition, patients by affected sinus opacification showed more frequently the postsellar type and were less affected by pneumatization variants of the sphenoid bone than the control group (P < 0.05).This study first suggests the possible protective role of variants of pneumatization in the development of sphenoid sinus opacification.

The association of superior attachment of uncinate process with pneumatization of middle turbinate: a computed tomographic analysis

The frontal sinus outflow pathway is complex and can be influenced by the configuration of the uncinate process (UP). The UP can attach superior to the lamina papyracea, skull base, and middle turbinate. The factors associated with superior attachment remain unclear. This study analyzed the relationships between different types of superior UP attachment and characteristics of the surrounding structures including the agger nasi cell, skull base, and middle turbinate. This retrospective study utilized computed tomography images of 836 sides with identifiable sinus structure from 434 Taiwanese patients. Types of superior UP attachment, height of the ethmoid cribriform plate, prevalence of agger nasi cell, and degree of pneumatization of the middle turbinate were analyzed. In the current study, neither the presence of an agger nasi cell nor height of the cribriform plate had significant relationship with superior UP attachment type. However, UP attachment type was statistically significantly associated with pneumatized middle turbinate (PMT) type (p < 0.01). The PMT group had a higher incidence of UP attachment to the middle turbinate (38%) than the non-PMT group (18%). In the extensive PMT group, the incidence of UP attachment to the middle turbinate was high to 49%. In conclusion, superior UP attachment to the middle turbinate was associated with pneumatization of the middle turbinate. The UP has a greater tendency to attach to the middle turbinate in cases with more PMT.

Outcomes of chronic frontal sinusitis treated with ethmoidectomy: a prospective study

BACKGROUND

In medically refractory chronic frontal sinusitis, ethmoidectomy without instrumentation of the frontal ostium may resolve frontal disease. Our aim was to determine the efficacy of ethmoidectomy alone for the treatment of chronic frontal sinusitis.

METHODS

Adults with chronic rhinosinusitis prospectively enrolled in a multicenter study who demonstrated frontal sinusitis on computed tomography were divided into 2 groups: (1) endoscopic sinus surgery (ESS) incorporating ethmoidectomy, but excluding frontal sinusotomy; and (2) ESS incorporating frontal sinusotomy. The primary outcome was improvement in 22-item Sino-Nasal Outcome Test (SNOT-22) scores. Secondary outcomes included endoscopic scores and use of corticosteroids and antibiotics.

RESULTS

A total of 196 cases undergoing frontal sinusotomy and 30 cases treated with ethmoidectomy without frontal sinusotomy were analyzed and were comparable demographically. The prevalence of nasal polyps, previous ESS, asthma, and aspirin intolerance was more common in the frontal sinusotomy group (p < 0.050). Preoperative endoscopy and computed tomography scores were higher in the frontal sinusotomy group (p ≤ 0.001). Postoperatively, both groups showed comparable SNOT-22 scores with worse endoscopy scores in the frontal sinusotomy group (p = 0.038). Postoperative improvement in SNOT-22 total and subdomain scores was comparable between groups. Nasal endoscopy scores improved to a greater degree in the frontal sinusotomy group (p = 0.023). Duration of postoperative topical steroid use was higher in the frontal sinusotomy group (p = 0.007). Revision surgery was needed in 2.6% of frontal sinusotomy patients and 0% of patients without frontal sinusotomy.

CONCLUSION

The treatment of chronic frontal sinusitis through ethmoidectomy is a potential alternative to frontal sinusotomy achieving similar quality of life (QOL) improvements in patients manifesting less severe sinus disease.