Background: The olfactory cleft (OC) comprising the olfactory epithelium (OE) is the most important anatomical location for olfactory function. Endoscopic sinus surgery (ESS) is used to treat diseases related to the OC and improve olfactory dysfunction. However, iatrogenic OE injury occasionally occurs. Comprehensive knowledge of the olfactory region is required to avoid damage to the OE during endoscopic procedures.Methods: Immunohistochemistry was performed on olfactory mucosa obtained from the unaffected side of olfactory neuroblastoma surgical specimens. The OE was defined as the epithelium containing mature olfactory sensory neurons (OSNs). The distribution and cell kinetics of the OE were examined. Results:The OE was selectively localized to the anterior two-thirds of the superior turbinate (ST) and in the nasal septum (NS) just opposite to the ST; the OE was not detected within the mucosa of the superior meatus. The density of mature OSNs was high at the ethmoid tegmen but gradually decreased with distance from the ethmoid tegmen. The extent of cell death and proliferation was relatively even across the OE. Analysis of airflow profiles revealed that resection of inferior ST does not decrease airflow to the OC. Conclusion:The results indicate that the distribution and degree of differentiation of mature OSNs are heterogenous throughout the OE. Epithelial resection of the anterior or superior ST has the potential to damage olfactory function. Resection of the inferior or posterior ST or widening of the superior meatus is a safer alternative that does not damage mature OSNs or alter airflow to the OC.

Objectives/Hypothesis Reconstruction of mucosal defects using free mucosal grafts has become a common procedure during endoscopic sinus surgery. Epithelialization of mucosal grafts affects postoperative complications and outcomes, which could be influenced by different recipient tissue. However, morphological changes occurring in the grafts transplanted over different tissues remain unexplored. Study Design An animal study. Methods Free mucoperichondrial grafts were prepared from the nasal septum of rabbits; the cartilage group had reconstruction on the nasal septal cartilage, and the perichondrium group had reconstruction on the contralateral perichondrium. The nasal septum was removed after 1 and 4 weeks of reconstruction, and the graft was histologically evaluated. Results After 1 week of reconstruction, the mucosal epithelium of grafts in the cartilage group disappeared, whereas the columnar epithelium of grafts was preserved in the perichondrium group. After 4 weeks of reconstruction, the mucosal defect site was covered with mucosal epithelium in both groups. However, while squamous epithelium was mostly observed in the cartilage group, columnar epithelium containing the healthy ciliary and goblet cells was observed in the perichondrium group. Statistically significant differences were detected in the parameters of epithelial morphology between the two groups, which were higher in the perichondrium group. Conclusions In the reconstruction of mucosal defects using free mucosal grafts, difference in recipient tissue affects the graft epithelial morphology. Level of Evidence NA Laryngoscope, 132:2301–2306, 2022

Skull base injuries caused by the outside-in frontal drill-out technique have not been reported. In this report, we chose an outside-in approach to open the frontal sinus for olfactory neuroblastoma resection. Although we identified the first olfactory fibre, the anterior skull base was damaged while drilling into the frontal sinus on the tumour side. We reconstructed the skull base in multiple layers using fascia and cartilage. Postoperative cerebrospinal fluid leakage or intracranial haemorrhage was not observed. In this case, a morphological difference existed in the posterior wall of the frontal sinus between the right and left sides, like a “hump” in the posterior wall of the frontal sinus. This case of damage to the anterior skull base that could not be avoided by identifying the first olfactory fibre alone is the first published case of skull base injury caused by the outside-in approach due to morphological variations of the frontal sinus and skull base. In this approach, the posterior wall of the frontal sinus cannot be observed because the intraoperative landmark is limited to the first olfactory fibre. Therefore, morphological variations of the posterior wall of the frontal sinus should be analysed in advance to prevent cranial base injury.

ObjectiveThe histological findings of wound healing depending on different nasal packing materials and replacement periods were lacking.MethodsMucosal defects were created in the nasal septum of rabbits and covered with Spongel®, Algoderm®, or Nasopore®, which were cleaned on Day 14. To investigate the effect of replacement durations, Spongel® was removed on Days 3 and 7. All nasal septal specimens were collected on Day 28. Samples without packing material were prepared as controls. Depending on residual packing materials in the regenerated tissue, specimens were classified into the remnant and non‐remnant groups, and morphology was compared using epithelium grade score and subepithelial thickness.ResultsThe epithelium grade score in the Spongel‐14d group was lower than that in the other groups (p < 0.05). Subepithelial thickness was higher in the Algoderm‐14d and Spongel‐14d groups (p < 0.05). Epithelium grade scores were higher and subepithelial thicknesses were lower in the Spongel‐3d and ‐7d groups than in the Spongel‐14d group. Epithelium grade score was lower and subepithelial thickness was higher in the remnant group (n = 10) than in the non‐remnant group (n = 15; p < 0.05).ConclusionsDifferences in packing materials and placement durations affected wound healing of nasal mucosa. The selection of appropriate packing materials and replacement duration was considered essential for ideal wound healing.Level of EvidenceNA Laryngoscope, 2023

A 69-year-old male patient presented to the hospital with a chief complaint of nasal obstruction. Physical examination revealed swelling of the anterior nasal septum and nasal dorsum and tender indurated oedema of the dorsum of both hands. Blood tests showed an elevated inflammatory response, and contrast-enhanced computed tomography (CT) showed a polycystic abscess in the nasal septum. Emergency surgery and histopathology were performed on the day of the initial visit for incisional drainage. Intraoperative findings showed white necrosis between the nasal septal cartilage and nasal septal mucosa, as well as white necrosis and pus accumulation in the periosteum and soft tissue of the piriform aperture and the nasal bone. The patient underwent endoscopic dissection and drained as much as possible, and the abscess and surrounding normal nasal septal mucosa were sampled for diagnostic purposes. The patient was diagnosed with vasculitis based on the clinical findings, pathological examination results, and blood test results. After the diagnosis was confirmed, steroid and cyclophosphamide pulse administration was initiated, and the swelling of the anterior nasal septum and nasal dorsum and the bilateral dorsal indentation oedema improved markedly. The patient is now doing well and will continue to be carefully monitored in the outpatient clinic.