Analysis of Histopathologic Characteristic and Treatment of Sinonasal Benign Tumor

BACKGROUND AND OBJECTIVES: The main treatment modality of sinonasal benign tumor is surgical resection, and the endoscopic intranasal approach has been commonly performed since the 1990s. The objective of this study was to evaluate the recurrence rates of different sinonasal benign tumors and to analyze the diverse approaches used in their surgical treatment. SUBJECTS AND METHOD: In 270 patients who were histopathologically diagnosed with sinonasal benign tumor during a period of 20 years, histopathologic type, treatment approach, interval between first treatment and recurrence, and recurrence rate according to treatment approach were analyzed. RESULTS: Recurrence rate was higher with the intranasal approach than with the extranasal approach in inverted papilloma and angiofibroma, but the differences were not statistically significant. The proportion of the intranasal approach during the latter 10 years was higher than that during the former 10 years. There was no significant differences between the recurrence rate during the former 10 years and that during the latter 10 years for both intranasal and extranasal approaches. CONCLUSION: Based on tumor location and stage and skill of the surgeon, the intranasal approach can replace the extranasal approach with no major changes in treatment outcome.

Clinical Features of Obstructive Sleep Apnea That Determine Its High Prevalence in Resistant Hypertension

PURPOSE: Resistant hypertension (HTN) occurs in 15-20% of treated hypertensive patients, and 70-80% of resistant hypertensive patients have obstructive sleep apnea (OSA). The characteristics of resistant HTN that predispose patients to OSA have not been reported. Therefore, we aimed to determine the clinical, laboratory, and polysomnographic features of resistant HTN that are significantly associated with OSA. MATERIALS AND METHODS: Hypertensive patients (n=475) who underwent portable polysomnography were enrolled. The patients were categorized into controlled (n=410) and resistant HTN (n=65) groups. The risk factors for the occurrence of OSA in controlled and resistant hypertensive patients were compared, and independent risk factors that are associated with OSA were analyzed. RESULTS: Out of 475 patients, 359 (75.6%) were diagnosed with OSA. The prevalence of OSA in resistant HTN was 87.7%, which was significantly higher than that in controlled HTN (73.7%). Age, body mass index, neck circumference, waist circumference, and hip circumference were significantly higher in OSA. However, stepwise multivariate analyses revealed that resistant HTN was not an independent risk factor of OSA. CONCLUSION: The higher prevalence and severity of OSA in resistant HTN may be due to the association of risk factors that are common to both conditions.

Neck Circumference and Lowest Oxygen Saturation Are Independently Associated with High Coexistence of Hypertension in Obstructive Sleep Apnea

PURPOSE: Obstructive sleep apnea (OSA) is considered an independent risk factor for hypertension. However, it is still not clear which clinical factors are related with the presence of hypertension in OSA patients. We aimed to find different physical features and compare the sleep study results which are associated with the occurrence of hypertension in OSA patients. MATERIALS AND METHODS: Medical records were retrospectively reviewed for patients diagnosed with OSA at Severance Cardiovascular Hospital between 2010 and 2013. Males with moderate to severe OSA patients were enrolled in this study. Clinical and polysomnographic features were evaluated to assess clinical variables that are significantly associated with hypertension by statistical analysis. RESULTS: Among men with moderate to severe OSA, age was negatively correlated with hypertension (odds ratio=0.956), while neck circumference was positively correlated with the presence of hypertension (odds ratio=1.363). Among the polysomnographic results, the lowest O2 saturation during sleep was significantly associated with the presence of hypertension (odds ratio=0.900). CONCLUSION: Age and neck circumference should be considered as clinically significant features, and the lowest blood O2 saturation during sleep should be emphasized in predicting the coexistence or development of hypertension in OSA patients.

IL-1beta Induces Lysozyme Overexpression through a Mechanism Involving ERK/p38 Mitogen Activated Protein Kinase Activation in Human Airway Epithelial Cells

BACKGROUND AND OBJECTIVES: Lysozyme, a major serous component of airway epithelial secretions, plays an important role in airway defense. However, little is understood about the regulation of its expression and the associated signaling pathway. The object of this study is to investigate the regulation of lysozyme expression, the downstream signaling pathway of lysozyme expression, and the related protein kinases under inflammatory conditions using the IL-1beta, which acts as a significant cytokine in many airway inflammations. MATERIALS AND METHODS: After the IL-1beta treatment of normal human nasal epithelial cells (NHNE), lysozyme mRNA expression was determined by RT-PCR. Expressed levels of ERK/p38 kinase were determined by Western blot analysis. RESULTS: IL-1beta treated NHNEcells had over-expressed lysozyme compared to the control group. Activated ERK/p38 kinase level showed marked increment by treating NHNE with IL-1beta. Lysozyme expression and ERK/p38 kinase levels decreased when inhibitors of ERK/p38 MAP kinases were added to the IL-1beta treated cells. Finally, expression of lysozyme and activated level of ERK/p38 MAP kinases decreased in a dominant-negative cell line even when treated with IL-1beta. CONCLUSION: From these results, we concluded that IL-1beta induces over-expression of lysozyme via ERK/p38 MAP kinase signaling pathways in airway epithelial cells.

Effects of Levocetirizine on Quality of Life in the Patients with Allergic Rhinitis

BACKGROUND AND OBJECTIVES: Allergy is a chronic disorder with undesirable consequences on the quality of life (QoL). The first aim of this study is to evaluate the impact of allergy on the QoL and to show the correlation between symptoms and categories of the QoL. The second purpose is to determine whether treatment with levocetirizine improves the QoL among allergic rhinitis patients. MATERIALS AND METHODS: A total of 412 allergic patients answered the questionnaire and its sensitivity was checked to validate its usefulness in asthma and allergic rhinitis patients. To evaluate the effect of applying levocetirizine for 1 month on the QoL among allergic rhinitis patients, a total of 94 subjects were assessed with the questionnaire and analyzed (paired t-test). To evaluate its effect on the symptoms of allergic rhinitis for the duration of 2 and 4 weeks, a total of 100 subjects were analyzed (repeated ANOVA) with the symptom questionnaire. RESULTS: Besides the physical symptoms, patients suffered from activity restriction, emotional problems, difficulty in being examined, and dissatisfaction with health status. The correlation between the questionnaire and the QoL was statistically significant. After treatment, the QoL and symptoms, except nasal congestion, were significantly improved. CONCLUSION: The questionnaire can be beneficial in assessing the QoL among allergic patients. Treatment with levocetirizine provides improvement in the QoL and lowers the symptoms score among allergic rhinitis patients.

MUC8 as a Ciliated Cell Marker in Human Nasal Epithelium / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: To examine the MUC8 mRNA expression patterns according to the mucociliary differentiation of the normal human nasal epithelial (NHNE) cells, and to investigate the localization of the MUC8 proteins in the nasal polyps. MATERIALS AND METHODS: The passage-2 NHNE cells were cultured using an air-liquid interface technique and nasal polyp specimens. On the 2, 7, 14, and 28 days after confluence, the ciliated cells were counted using cytospin slide immunostaining using H6C5 and beta-tubulin, and the MUC8 mRNA levels were determined using real-time quantitative PCR. After synthesizing the polyclonal anti-MUC8 peptide antibodies, MUC8 immunostaining was preformed using the nasal polyps. The MUC8 mRNA and protein levels were determined with the NHNE cells treated with IL-1beta (10 ng/ml for 24 hours) using RT-PCR and Western blot analysis. RESULTS: The increasing pattern of the number of ciliated cells as well as the MUC8 gene expression level with increasing culture time in the NHNE cells was quite similar. MUC8 was expressed in the ciliated cells of the human nasal polyps. The MUC8 protein level as well as the mRNA level was up-regulated as a result of the IL-1beta treatment. CONCLUSIONS: This study indicates that the MUC8 protein is expressed in ciliated cells from the human nasal epithelial cells and is up-regulated by the IL-1beta treatment. These results suggest that the MUC8 gene and protein expression levels might be used as a ciliated cell marker in the human nasal epithelium.

15-Lipoxygenase-1 Induced by Interleukin-4 Mediates Apoptosis in Oral Cavity Cancer Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In oral cavity cancer (OCC) cells, the effects of interleukin-4 (IL-4) are various according to the cell specificity. However, if IL-4 induces apoptosis on OCC cells, the mediator of this apoptosis is uncertain. Therefore, we investigated whether apoptosis of OCC cells occurs by IL-4 and whether 15-lipoxygenase-1 (15-LO-1) induced by IL-4 is the possible mediator of this apoptosis. MATERIALS AND METHODS: SCC 1483 cells were used. Flow cytometry and poly ADP-ribose polymerase cleavage were used to examine apoptosis. Western blot analysis and reverse transcription-polymerase chain reaction were used to measure 15-LO-1 protein and mRNA. RESULTS: The inhibition of cell proliferation by more than 50% was noted from 10 ng/ml of IL-4. At this dose, apoptosis was observed and this apoptosis was inhibited by 2.2 microM caffeic acid. 15-LO-1 expression was observed from the 8 hour treatment of IL-4 and apoptosis increased after the 24 hour treatment of IL-4. In this apoptosis, caspase cascade, cyclooxygenase-2, and non-steroidal anti-inflammatory drugs-activated gene-1 (NAG-1) were not involved. CONCLUSION: IL-4 induced apoptosis in SCC 1483 OCC cells and 15-LO-1 induced by IL-4 may mediate this apoptotic pathway.

Membrane-Specific Expression of Functional Purinergic Receptors in Normal Human Nasal Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Extracellular purines and pyrimidines regulate various physiological responses via cell surface receptors known as purinoreceptors, and may exert autocrine or paracrine effects on ion transport, fluid transport, ciliary beat frequency and mucin secretion. This study aims to investigate the expression patterns of such purinoreceptors found in normal human nasal epithelial (NHNE) cells. MATERIALS AND METHOD: In RT-PCR, the mRNAs for several P2X (P2X3, P2X4, P2X7) and P2Y (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12) receptors were identified in NHNE cells. Functional localizations of P2 receptors were investigated by measuring [Ca2+]i increases in a membrane-specific manner using a double-perfusion chamber. Absence of the responses of -Me ATP and 2MeS-ATP excluded functionally active P2X3, P2X4, and P2Y1 receptors as far as [Ca2+]i increase was concerned. RESULTS: Applications with ATP and UTP revealed that luminal membranes of NHNE cells express P2Y2 and P2Y6 receptors and basolateral membranes P2Y2 receptors. Expressions of P2Y2 and P2Y6 receptors in NHNE cells were further verified by the immunoblotting using specific antibodies. In addition, the results with BzATP indicated that the P2Y11 receptor may be present on the luminal side. CONCLUSION: The NHNE cells express functionally active P2Y2, P2Y6 and P2Y11 receptors in a membrane-specific pattern, which may play an important role in the control of mucin and fluid secretion in NHNE cells.

Optic Nerve Injury Secondary to Endoscopic Sinus Surgery: an Analysis of Three Cases

Major orbital complications after the endoscopic sinus surgeries are rare and of these, optic nerve injury is one of the most serious. This study was to undertaken to analyze 3 cases of optic nerve injury after endoscopic sinus surgery. The three cases included one patient with a loss of visual acuity and visual field defect, and two patients with total blindness. In all cases, no improvement of visual acuity was observed despite treatment. It is important to frequently check the location and direction of the endoscope during surgery to avoid optic nerve injury. In addition, surgeons must have a precise knowledge of the detailed anatomy through cadaver dissections, an ability to interpret the PNS CT scan and experienced procedural surgical skills.

15-Lipoxygenase-1 Mediates Mucociliary Differentiation in Normal Human Nasal Epithelial Cells

BACKGROUND AND OBJECTIVES: 15-lipoxygenase-1 (15-LO-1) is involved in the differentiation of human tracheobronchial epithelial cells. Here we investigated the relation between 15-LO-1 expression and the differentiation of normal human nasal epithelial (NHNE) cells. MATERIALS AND METHODS: NHNE cells, RT-PCR, Western blot analysis, and scanning electron microscopy (SEM) were used. RESULTS: In retinoic acid (RA)-sufficient culture media, 15-LO-1 expression in NHNE cells increased time-dependently, but its expression was undetectable in RA-deficient culture media. Moreover, in RA-deficient culture media, IL-4 time-dependently induced 15-LO-1 expression at a concentration of 1 ng/mL. In addition, MUC8 gene expression, a marker of mucociliary differentiation, was up-regulated by 15-LO-1, which was itself induced by IL-4. In SEM, the ciliated epithelium was observed with the treatment of IL-4. CONCLUSION: Our findings suggest that 15-LO-1 may be related to the differentiation of human nasal epithelium, and that it may mediate the mucociliary differentiation of NHNE cells.

Induction of Non-Steroidal Anti-Inflammatory Drug-Activated Gene(NAG-1) in Human Oral Cavity Cancer Cells and its Effect on Apoptosis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Nonsteroidal anti-inflammatory drug (NSAID)-activated gene (NAG-1), which is induced by NSAIDs, has proapoptotic and antitumorigenic effects in colorectal cancer cells. However, NAG-1 induction and its effect on the apoptosis in human oral cavity cancer cells (SCC 1483) have not been determined. MATERIALS AND METHOD: NAG-1 expression by various NSAIDs in SCC 1483 cells was investigated by Western blot analysis. The induction of apoptosis by NSAID and the relationship between NAG-1 expression and apoptosis were determined by Western blot assay and flow cytometry. Drosophila cells stably expressing NAG-1 were constructed and NAG-1 conditioned medium (NCM) were made. Apoptosis was examined with flow cytometry on SCC 1483 cells treated with NCM. RESULTS: Diclofenac was the most potent inducer of NAG-1. Diclofenac inhibited the proliferation of SCC 1483 cells and this inhibition was proved as apoptosis. Diclofenac induced the expression of NAG-1 and also induced apoptosis in time and dose dependent manner. In the concentrated NCM, the expression of NAG-1 was intense and apoptosis was induced by addition of 5 mu of NCM. CONCLUSION: Based on these data, we could assure that NSAIDs induced NAG-1 in oral cavity cancer cells and NAG-1 induced apoptosis. Therefore, we suggest that it is possible to use NSAIDs as a chemopreventive agent in oral cavity cancer. Further studies on the mechanism of NAG-1 and clinical use will be needed.

Structural Changes of Inferior Turbinate in Patients with Septal Deviation: Surgical Implication

Septal deviation causes various nasal symptoms and other sinonasal disease. We evaluated the relationship between septal deviation and morphologic changes of the inferior turbinate. PNS CT of 31 patients (septal deviation group) and 20 normal subjects (normal control group) were reviewed. We measured the thickness of the inferior turbinate and the angle between the lateral nasal wall and the inferior turbinate in each group. Each measurements were analyzed using t-test and compared. The thic-kness of the inferior turbinate and the angle between the lateral nasal wall and the inferior turbinate showed no difference between the right and left side in the control group. The same measurement of the convex side in the septal deviation group were not different from those of the control group. However, the thickness of the inferior turbinate and the angle between the lateral nasal wall and the inferior turbinate differed significantly from the control group data. Changes of the inferior turbinate in septal deviation were caused not only by hypertrophy of the inferior turbinate, but also by the increased angle between the lateral nasal wall and the inferior turbinate.

Surgical Outcome of Radical Maxillectomy in Advanced Maxillary Sinus Cancers

We investigated the surgical outcome of radical maxillectomy in advanced maxillary sinus cancers invading through the posterior wall and into the infratemporal fossa. Twenty-eight patients with maxillary sinus squamous cell carcinoma, who visited the Otorhinolaryngology Department at Severance Hospital from March, 1993 to February, 2001 and underwent the surgery, were analyzed retrospectively by reviewing clinical medical records and radiologic test results. The mean follow- up period was 78.8 months. (26 -162 months) Local recurrence, sites of local recurrence, and the 2-year disease-free survival rate were analyzed. Of the total 28 cases, 9 cases were T3, and 19cases were T4. Total maxillectomy was performed in 12 cases (42.9%) and radical maxillectomy in 16 cases (57.1%). Regardless of staging, radical maxillectomy was performed only when cancers invaded through the posterior wall and into the infratemporal fossa. When cancers only maginally or did not invade the posterior wall, total maxillectomy was performed. The 2-year disease-free survival rate was 75% for both total and radical maxillectomy, and the local recurrence rates were 8.3% and 18.7% respectively. All recurrence occurred at the posterior resection margin of the maxillectomy. We strongly recommend the use of radical maxillectomy in the cases of advanced maxillary sinus cancers invading the infratemporal fossa. Radical maxillectomy can provide sufficient safety margins and lower the local recurrence rate.

UTP and ATPgammaS Induce Mucin Secretion via Ca2+ Dependant Pathways in Human Nasal Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Nucleotides such as adenosine triphosphate (ATP) and uridine-5-triphosphate (UTP) play fundamental roles in the early stage of secretion in nasal epithelial cells via P2Y receptor. In the present study, we examined the expression pattern of P2Y subtypes and their functions on Ca2+ influx ([Ca2+]i) in normal human nasal epithelial (NHNE) cells. We also examined the effect of UTP (agonist for P2Y2) and ATPgammaS (agonist for P2Y11) on mucin secretion and mucin gene expression. MATERIALS AND METHOD: The expression pattern of P2Y receptors and mRNA levels of MUC5AC, MUC5B and MUC8 were examined after treatment with UTP and ATPgammaS by RT-PCR. Mucin was quantitated by immunoblotting assay. We measured the [Ca2+]i in NHNE cells with a double perfusion chamber. RESULTS: Two uracil-sensitive receptors (P2Y2, P2Y4) and two adenine-sensitive receptors (P2Y1, P2Y11) were expressed in NHNE cells. UTP and ATPgammaS increased [Ca2+]i via caffeine-sensitive pathways, and these two agonists stimulated mucin secretion to a similar magnitude without their gene enhancement. In addition, the mucin stimulatory effects subsided when the intracellular Ca2+ was removed by 2-bis (2-aminophenoxy) ethane-N, N, N', N'-tetraacetic acid-acetoxymethyl ester. CONCLUSION: Our study showed that P2Y2 and P2Y11 receptors were expressed in NHNE cells and that their agonists, UTP and ATPgammaS, act as secretogogues on mucin secretion via Ca2+-dependent pathways.

Mucociliary Differentiation according to Time in Human Nasal Epithelial Cell Culture / 대한이비인후과학회지

In cell culture studies using human nasal epithelial cells, information regarding the state of differentiation, cell phenotype, and gene expression for mucus production would be important to have in relations to different culture time as these factors may vary according to the length of culture period. The primary purpose of this research was to determine whether the number of the ciliated cells increases as a function of differentiation in normal human nasal epithelial (NHNE) cells. When an increase was observed in the number of ciliated cells, we determined the composition ratio of ciliated cells and secretory cells according to the culture duration. At the same time, we also examined the levels of mucin and lysozyme secretion at the same time. The presence of ciliated cells was not evident up to 2 days after confluence. However, 3.1+/-0.2%, 7.4+/-0.5%, and 14.5+/-0.6% of the cells were ciliated 7, 14, and 28 days after confluence, respectively. Meanwhile, the percentage of secretory cells were 35.6+/-2.8%, 32.8+/-2.5%, 32.8+/-2.5%, and 49.4+/-1.4% on the 2, 7, 14 and 28 days after confluence, respectively. The amount of secreted mucin showed an abruptly increasing pattern by the 14th day of confluence, but showed no significant changes thereafter. The amount of secreted lysozyme increased as a function of differentiation. We concluded that in in vitro studies with NHNE cells, the time point of treatment should vary according to the purpose of the study.

A Case of Solitary Fibrous Tumor of the Nasal Cavity

Solitary fibrous tumor (SFT) belongs to a group of mesenchymal tumors, first described as a primary spindle cell tumor of the pleura in 1931. Recently, SFT has been reported in various locations with no relation to serosal surface, such as the mediastinum, head and neck, orbit and urogenital system. Histopathologically, the tumors have a disorganized or "patternless" arrangement of spindle cells in a collagenous background and prominent vascular channels of varing size. To date, only 22 cases of SFT arising from the nasal cavity and paranasal sinuses have been reported in the world literature. We report a case of SFT localized in the right nasal cavity with extension to the right ethmoid sinus with a review of literature.

Effect of Patient-Controlled Analgesia after Tonsillectomy with Laser Resection of Palatopharynx (LRPP)

BACKGROUND AND OBJECTIVES: Pain control is one of the most important factors for the patients that underwent the snoring surgery. This study was performed to investigate the effectiveness of intravenous patient-controlled analgesia (PCA) for postoperative pain control after tonsillectomy with laser resection of palatopharynx. MATERIALS AND METHODS: In this double-blind randomized study, 44 patient were randomly allocated to 2 groups. In the PCA group comprising 32 patients, fentanyl citrate, ketorolac tromethamine and zofran in normal saline solution were administered by PCA equipment. In the control group comprising 12 patients, normal saline solution was given without analgesic drug by PCA equipment. Visual analogue pain score (VAS) was recorded right after surgery and 2, 4, 6, 12, 18, and 24 hours after surgery and satisfaction score was recorded just before discharge from the hospital. RESULTS: VAS was significantly higher in the control group of all time points. Overall satisfaction score was also higher in PCA group than control group. CONCLUSION: The results of this study suggest that intravenous PCA is an effective method for postoperative pain control after tonsillectomy with laser resection of palatopharynx.

The Effect of MAC (Monitored Anesthesia Care) on Perioperative Pain in Endoscopic Sinus Surgery

BACKGROUND AND OBJECTIVES: Pain and anxiety control is the most important factor for patients that have undergone endoscopic sinus surgery under local anesthesia. Monitored anesthesia care (MAC) technique has been applied to local anesthetic patients for anxiolysis and analgesia. This technique encompasses the use of sedatives, tranquilizers and analgesics in combination to local supplements. This study was performed to evaluate the effectiveness of MAC for intraoperative pain control in patients who have undergone endoscopic sinus surgery. MATERIALS AND METHODS: We studied 83 patients undergoing ambulatory endoscopic sinus surgery. Patients were randomly allocated into 2 groups of MAC (n=49) and placebo (n=34). We administrated alfentani1 and propofol intravenously at 2-3 minutes before local anesthesia for endoscopic sinus surgery. We evaluated the intraoperative pain with visual analogue pain score (VAS) and satisfactory score to pain control. RESULTS: Overall, MAC cases showed statistically significant better VAS than placebo cases. Satisfactory score to pain control was also higher in MAC cases than placebo cases. CONCLUSION: We conclude that MAC is an effective method using intravenous sedatives and analgesics for intraoperative sedation and pain control in patients undergoing endoscopic sinus surgery under local anesthesia.

The Application of Laser Doppler Flowmetry for Allergic Rhinitis and Rhinitis Medicamentosa

BACKGROUND AND OBJECTIVES: Allergic rhinitis (AR) and rhinitis medicamentosa (RM) have different mucosal color and pathophysiology. To investigate whether the mucosal color and nasal blood flow are different between the diseases in spite of same symptoms, we designed this study. Materials and Methods: 20 patients with allergic rhinitis and 21 patients with rhinitis medicamentosa were compared with 20 normal volunteers using mucosal color grading and Laser Doppler flowmetry. The Laser Doppler flowmetry was performed with a Periflux 4001 (Perimed, Jrtlla, Sweden) and perfusion unit (PU), velocity unit (VU), and concentration Unit (CU) were measured. The Laser Doppler flowmetry data in AR and RM were compared with those of the normal subjects, and between AR and RM. RESULTS: The perfusion score of AR and RM were lower than the control (p<0.05) and it was statistically significant that the mucosal color of AR were pale and of RM were reddish, comparing to the control group (p<0.05). CONCLUSION: The nasal blood flow was decreased with AR and RM compared to control but the mucosal color of AR and RM were different because of the difference of pathophysiology of diseases. When diagnosing RM, observation of mucosal color and measurement of nasal blood flow will be helpful besides the history of long-term use of nasal decongestant.

Surgical Anatomy of the Anterior Ethmoidal Canal in Ethmoid Roof: Anatomical and Computed Tomographic Analysis / 대한이비인후과학회지

BACKGROUNDS AND OBJECTIVES: This study was undertaken to examine three main relationships. First, the distance and angle from the anterior ethmoid canal to the limen nasi and the sill were measured. Second, The location of the anterior ethmoid canal was examined in relation to the lamellas and the skull base. Third, the existence of bony defects in the canal and the course through the anterior cranial fossa were studied. MATERIALS AND METHODS: This study employed both sagittal computed tomography and cadaver dissection. Seventy sagittally divided heads from randomly chosen Korean adult cadavers were used. Sagittal computed tomography was performed on all specimens. Then they were meticulously dissected under a surgical microscope. RESULTS: The mean distance and angle between the limen nasi and the anterior ethmoid canal was 49.0 mm and 54.5, respectively. The anterior ethmoid canal was located between the 2nd and 3rd lamella in 61 of 70 cases. In 60 of 70 cases, it was attached to the base of the skull, and in the remaining 10 cases, it ran 2 to 3 mm below the skull base. When viewed from the superior side, the course of the anterior ethmoid canal formed a diagonal line from the lateral to the medial side. Partial bony defects of the anterior ethmoid canal were observed in eight cases and complete bony defects in none. CONCLUSION: This study provides surgeons with a better understanding of the anatomy of the anterior ethmoid canal.