Comparison of Clinical Features between Noroviral and Rotaviral Gastroenteritis

OBJECTIVE: Rotavirus and norovirus are the most common pathogens causing acute gastroenteritis in children. As the incidence of noroviral gastroenteritis increases, it is becoming more important to identify the clinical features of noroviral infection. We compared the clinical features of noroviral gastroenteritis and rotaviral gastroenteritis. METHODS: This study included 79 children with noroviral and 151 children with rotaviral gastroenteritis, who were admitted to the Soonchunhyang University Gumi Hospital between January 2013 and December 2014. We reviewed their medical records and compared the clinical features of gastroenteritis between the two groups respectively. RESULTS: In those belonging to the norovirus group, the mean age was 29.65 months, which was younger than that of the rotavirus group, at 34.74 months. Patients suffering from noroviral gastroenteritis experienced more vomiting (5.6 episodes/day) than diarrhea (3.5 episodes/day). Vomiting, diarrhea, and fever were all less severe in those suffering from noroviral gastroenteritis. It is commonly noted that patients with noroviral infection have vomiting and diarrhea without fever (55.0%), while those with rotaviral infection present with vomiting, diarrhea, and fever (44.3%). CONCLUSION: Although noroviral gastroenteritis is less severe than rotaviral gastroenteritis, the incidence of noroviral infection is increasing, and the mean age group infected with this virus is getting younger; thus, noroviral infection must be considered in the differential diagnoses in young patients with gastroenteritis.

A case of gastric trichobezoar causing psychiatric problems / 소아과

Trichobezoar is characterized by the accumulation of hair in the gastrointestinal tract and usually occurs in those who have trichotillomania, other psychiatric disorders, or neurologic problems. Trichobezoar typically presents as gastric obstruction, including abdominal pain, vomiting, anorexia, and weight loss. A 9-year-old girl visited our clinic with the complaint of abdominal discomfort and vomiting. A review of her medical history revealed that she had trichophagia since the age of 5, and she felt that her parents had been strict with her. She underwent gastrotomy, during which a large trichobezoar was removed. This case highlights the importance of psychiatric and comprehensive approaches in patients with trichobezoar.

Clinical Characteristics of Allergic Rhinitis According to Allergic Rhinitis and Its Impact on Asthma Guidelines

OBJECTIVES: The Allergic rhinitis and its impact on asthma (ARIA) guidelines were suggested for use to classify allergic rhinitis (AR). However, few studies have been performed in Asians. The objective of this study is to identify the clinical characteristics of AR in Korean patients according to the ARIA guidelines. METHODS: For the study, 610 patients who had been diagnosed with allergic rhinitis at Seoul National University Bundang Hospital and 545 patients who had been diagnosed with allergic rhinitis at 3 local clinics were included. All the patients were categorized into 4 groups, such as the mild intermittent, mild persistent, moderate-severe intermittent and moderate-severe persistent groups. The patients were given a questionnaire on allergic rhinitis-related symptoms and they underwent blood tests, including the blood eosinophil count and the serum total IgE level. RESULTS: The most prevalent type was the moderate-severe persistent group (34.7%), and the moderate-severe intermittent group (17.1%) was the rarest. There were significant differences among the 4 groups for olfaction (P<0.001), self-awareness of rhinitis (P=0.013), a previous history of AR (P<0.001), self-awareness of asthma (P=0.001) and allergic conjunctivitis (P<0.001). On the allergy laboratory tests, there was a significant difference between the groups for the eosinophi count (P=0.004). The number of blood eosinophil was more in the persistent groups than in the intermittent groups. CONCLUSION: According to the ARIA guidelines, the moderate-severe persistent group was the most prevalent for Korean patients. Blood eosinophilia and olfactory dysfunction were the most severe in the moderate-severe persistent group.

Allergic Immune Reaction in Recurrent Aphthous Ulceration by Multiple Allergosorbent Test(MAST) / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Recurrent aphthous ulceration (RAU) is most common among benign oral mucosal diseases, but its pathogenesis is not clearly defined yet. We aimed to evaluate the allergic reaction and identify the allergen by using the multiple allergosorbent test (MAST). SUBJECTS AND METHOD: We selected a total of 20 patients with RAU. RAU was not diagnosed by biopsy but by clinical findings, and MAST was performed in all patients. Parameters used were total IgE concentration, type of positive allergens, and the specific IgE concentration. RESULTS: The results were as follows: 1) The total IgE concentration was increased more in the RAU group than in the control group (p<0.05). 2) The type of positive allergens was multiple and had more even distribution in the RAU group than in the control group (p<0.05). 3) The specific IgE concentration according to the positive allergen was higher in the RAU group than in the control group (p<0.05). CONCLUSION: Allergic reactions could be invol-ved in the pathogenesis of RAU. The pathomechanism of allergic reaction to the RAU and the feasibility of treatment options such as avoidance therapy, the immune therapy, and the antihistamine usage need further study.

Multicenter Evaluation on the Safety of Gore-Tex as an Implant in Rhinoplasty / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study was done to evaluate the safety of Gore-Tex as a nasal implant. Materials and METHOD: A retrospective multicenter study was carried out on 15 surgeons from 11 general hospitals and 4 private practice clinics regarding the safety of the Gore-Tex as a nasal implant. The study involved 853 patients, of whom 656 received primary surgery and 197 revision surgery. Gore-Tex was mainly used as a dorsal implant in a form of sheet or as a reinforced nasal implant. RESULTS: The overall complication rate associated with Gore-Tex was 2.5% (21 cases). Infection was the most common complication (18 cases ; 2.1%) followed by 2 cases of seroma and 1 case of persistent nasal swelling. In 19 out of 21 complication cases, the graft needed removal to control the infection or seroma (91% removal rate). Nine cases of infection developed in both primary cases (1.37%) and in revision cases (4.57%), which suggests a higher association rate between infection and revision cases (p=0.0062). Infection developed within 1 month in 5 cases while 9 cases developed infection after 6 months of operation. Other complications such as aesthetic problems (malpositioning of the implant or dorsal irregularities) were found in 15 cases (1.8%) and hematoma in 1 case. CONCLUSION: The infection rate of Gore-Tex used in rhinoplasty was about 2% and it rose significantly in the revision cases. If infected, almost all of the implanted Gore-Tex needs removal; therefore, we suggest judicious use of Gore-Tex in rhinoplasty.

A Case of Non-Hodgkin's Lymphoma of the Oral Cavity Presenting as a Buccal Mass / 대한이비인후과학회지

Non-Hodgkin's lymphoma is a heterogenous group of neoplasm affecting the lymphoid system. About 10% of Non-Hodgkin's lymphoma occur in the extra-nodal region in the head and neck area and more than half of extra-nodal lymphoma in the head and neck area involves the Waldeyer's ring. Localization in the oral cavity is rare. We experienced one rare case of Non-Hodgkin's lymphoma in the oral cavity, with trismus and persistent ulcerated swelling in the right-side cheek as the chief complaint.

Effects of Dexamethasone on RANTES Expression of Nasal Fibroblast / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Fibroblasts play an indirectly augmenting effector role in allergic inflammatory response by releasing different proinflammatory cytokines, including RANTES, GM-CSF, IL-8 after stimulation by other inflammatory cytokines such as IFN-gamma, TNF-alpha. The aim of this study was to investigate expression of RANTES in allergic and non-allergic nasal fibroblasts after stimulation with IFN-gamma and TNF-alpha, and to study the effect of dexamethasone on the RANTES expression of nasal fibroblast cell. MATERIALS AND METHODS: Using the 3rd passage of fibroblasts taken from the inferior turbinates of allergic and non-allergic patients, we evaluated the RANTES expression of fibroblasts after the IFN-gamma, TNF-alpha stimulation in the presence or in the absence of dexamethasone by ELISA. RESULTS: The expression of RANTES in allergic nasal fibroblasts stimulated by cytokines was stronger than in non-allergic nasal fibroblasts stimulated by cytokines. And dexamethasone suppressed the RANTES expression in allergic nasal fibroblasts stimulated by IFN-gamma. However, dexamethasone did not affect the RANTES expression in allergic fibroblasts stimulated by TNF-alpha and non-allergic fibroblasts stimulated by IFN-gamma and TNF-alpha. CONCLUSION: This study shows different responses of the RANTES production in nasal fibroblasts to dexamethasone, perhaps reflecting heterogeneity of nasal fibroblasts.

Effects of External Nasal Dilators on Nasal Respiration and Patency in Patients with Deformity of the Nasal Septum by Mladina ClaSSIFICATION: An Acoustic Rhinometric Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The external nasal dilator (END) was designed to improve nasal respiration by expanding the nasal valve area and authors have proven in previous reports that the END improves nasal respiration and patency in patient with DSN. The present study attempts to assess the different effects of the END on nasal respiration and patency in DSN patients with dysfunction of the nasal valve area and in those with dysfunction of some other areas. MATERIALS AND METHODS: Fourty-six male patients (ages 18-49, average age 31.5) without any other nasal or sinus disease and who are not classified as Mladina types 1, 4 or 7 were used as subjects. The type of DSN was determined by Mladina classification. Those with dysfunction of the nasal valve area (Type 2) were classited as Group A and those with dysfunction of some other anatomical area as Group B (Type 3, 5, 6). The subjective sensation of nasal respiration, average minimum cross-sectional area (MCA) and nasal volume (V5: nasal volume from 0-5 cm) of all subjects were assessed and compared before and after the application of an END. RESULTS: Subjective sensation of nasal respiration, MCA and V, improved sign ificantly in both groups after the application of an END, but there were no significant differences between the two groups. CONCLUSION: Although an F,ND significantly improves nasal respiration and patency, this effect does not show any significant differences between patients with dysfunction of the nasal valve area and those with dysfunction of some other anatomical areas. This is because ENDs equally affect all Types of septal deformity.

A Case of Angiosarcoma of the Maxillary Sinus / 대한암학회지

Angiosarcomas are extremely rare in the nasal cavity and para-nasal sinus. Upto the present only nineteen cases have been reported in the literature. A 31-year-old male presented with right facial swelling and large oral cavity mass. He was treated with wide excision of the tumor by radical maxillectomy. The tumor was diagnosed as angiosarcoma by immunohistochemical staining with factor VIII-reactive antigen. No adjuvant radiotherapy after surgery was done. After 9 montbs from surgery, the tumor recurred in the primary sites of oral cavity and right maxillary sinus and metastasized to the both lungs. He was treated with palliative chemotherapy and showed a stable disease in follow-up magnetic resonance image of para-nasal sinus and simple chest X-ray after second cycle of chemotherapy. He is undergoing further chemotherapy without any problems. We report first in Korea a case of primary angiosarcoma of the right maxillary sinus in a 31-year-old male.

Significance of Fine-Needle Aspiration Cytology and Frozen Section Biopsy of Thyroid Nodules / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Although fine needle aspiration (FNA) cytology is a safe, simple and relatively accurate procedure, satisfactory samples cannot be obtained in about 10-20% of cases and there is also difficulty in differentiating between benign and malignant lesions in follicular neoplasm. Authors have compared preoperative FNA results and frozen section biopsy with permanent histologic findings and evaluated the significance of FNA cytology and frozen section biopsy in the diagnosis of thyroid nodules. MATERIALS AND METHODS: The medical records of 136 patients who underwent FNA cytology and thyroidectomy from October 1, 1993 to September 30, 1998 at the department of Otolaryngology and General Surgery of Ewha Womans University Mokdong Hospital were retrospectively analyzed. RESULTS: Among the 136 patients who received FNA, there were 75 cases (55.1%) diagnosed as benign, 30(22.1%) as malignant, 13(9.6%) as suspicion of malignant and 18(13.2%) as unsatisfactory. Sensitivity of FNA was 77.1%, the specificity 91.4%, and the accuracy 85.6%. Frozen section biopsy was performed in 118 patients and the sensitivity and specificity rate was 78.3% and 100%, respectively. CONCLUSION: FNA cytology has a high sensitivity (77.1%) and specificity (91.4%) rate. It is therefore a valuable initial procedure for diagnosing thyroid nodules and reducing unnecessary extensive surgery. When FNA yields a diagnosis of follicular neoplasm, frozen section biopsy having a specificity rate of 100% is an important step in determining the extent of operation.

A Study of Non-Convective Factor of Caloric Nystagmus in Relationship between Head Position and Maximal Slow Phase Eye Velocity / 대한이비인후과학회지

Background and OBJECTIVE: There are strong evidences that the caloric nystagmus may be due to non-convective factors in addition to the widely accepted Barany's convection theory. The influence of non-convective factor on the caloric nystagmus was interpreted by measuring the maximal slow phase eye velocity according to the head position. MATERIALS AND METHODS: In 18 normal ears, the maximal slow phase eye velocity of the cold caloric nystagmus was measured at five (-15degrees, 05degrees, 305degrees, 455degrees, 605degrees) different head positions. RESULTS: The sine value of the angle of the lateral semicircular canal (LSCC) plotted against the maximal slow phase velocity showed linear relationship without crossing the zero point in linear regression analysis. CONCLUSION: Maximal slow phase eye velocity shows linear relationship with the sine value of the angle of the LSCC. Compared with the curve expected by the convective factor, the curve in this study was biased by a constant amount (about 20%), which can be attributed to non-convective factor.

Effects of External Nasal Dilators on Nasal Respiration and Patency in Patients with Deformity of the Nasal Septum: An Acoustic Rhinometric Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Some types of deformities of the nasal septum (DNSs) interfere with the nasal valve function. External nasal dilators (ENDs) were developed to improve the nasal airway by mechanically dilating the nasal valve. The aim of this study is to evaluate the effects of ENDs on nasal respiration and patency in patients with DNS. MATERIALS AND METHODS: Fifty-four patients with DNS (37 males and 17 females, aged 18 to 46 years) without other sinonasal diseases were included in this study. All subjects were required to assess their own sensation of nasal respiration on a 100 mm visual analog scale. Minimal cross-sectional areas (MCAs) and volumes of 0 to 5 cm from the nostril (V 5s) of both nasal cavities were measured by acoustic rhinometry, respectively. All measurements before application of an END were compared with those 5 minutes after application. RESULTS: The subjective sensation of nasal respiration improved significantly after application of an END in both male and female. The END increased MCA and V5 significantly in both sexes. However, there were no significant correlations between changes in the subjective and objective parameters. CONCLUSION: ENDs offer an effective, nonsurgical therapeutic approach in the management of DNS by improving nasal respiration and by increasing MCA and nasal cavity volume. However, it should be kept in mind that this improvement in nasal patency does not always coincide with the improvement in subjective sensation of nasal respiration.

Effects of External Nasal Dilators on Snoring and Obstructive Sleep Apnea in Korean Adults: A Polysomnographic Study / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: It was reported that external nasal dilators (ENDs) can reduce snoring and obstructive sleep apnea (OSA) in white people by dilating the nasal valve area and then, improving nasal breathing. However, there are no available data on Asians, whose geometry of nasal cavities is different from that of white people. The aim of this study is to evaluate the effects of ENDs on snoring and OSA in Korean adults. MATERIALS AND METHODS: Twelve simple snorers (3 female and 9 males, aged 19 to 44 years) and 35 OSA patients (35 males, aged 22 to 65 years) without nasal diseases were included in this study. Polysomnography including measurement of snoring intensity was performed at two separate nights, one with and the other without an END. Averaged maximum snoring intensity, apnea index (AI), respiratory disturbance index (RDI), ratio of deep sleep (stage 3 and 4) to total sleep time, and minimum arterial oxygen saturation (SaO2) with and without an END were measured and compared. RESULTS: Snoring intensity was reduced in 6 (50.0%) of 12 simple snorers and 16 (45.7%) of 35 OSA patients. In overall, snoring improved significantly in both groups. In OSA patients, AI and RDI improved significantly, but ratio of deep sleep time and minimum SaO2 did not. There were no significant correlations between change of snoring intensity and change of AI or RDI in OSA patients. CONCLUSION: These results suggest that ENDs are helpful to improvement of snoring and respiration during sleep, but the sleep stages remain almost unchanged by ENDs in Korean adults with snoring and/or OSA.

Effects of IFN - gamma on Spheroid and Raft Culture of Squamous Cell Carcinoma of the Head and Neck / 대한암학회지

PURPOSE: To establish new in vitro model systems that better reflect in vivo condition, multicellular tumor spheroids(MTS) and raft culture were developed using cell lines of squamous cell carcinoma(SCCHN) of the head and neck. In these 3-dimensional systems, the expression of cell surface molecules which are important for modulation of physiology of tumor cells were studied with or without the treatment of interferon(IFN)-gamma. MATERIALS AND METHODS: Four SCCHN cell lines were used for MTS and raft culture. The effects of interferon-gamma on SCCHN cells were examined by immunohistochemistry. RESULTS: All cell lines formed MTS, but only Tu-138 showed a good stratification at the air-liquid interface in the raft culture system. Immunohistochemical studies of MTS using monoclonal antibodies revealed a strong staining for MHC class I, no staining for MHC-DR, a weak patch expression of ICAM-1 and a central strong staining for integrin a 6. Staining patterns were similar for the raft cultures except integrin a 6(intense full-thickness positivity). In both systems, IFN-gamma enhanced the expression of MHC-DR and ICAM-1. No significant change was found in the expression of MHC class I and integrin a 6. CONCLUSIONS: MTS and raft culture system were established successfully from the SCCHN cell lines. IFN-gamma can modulate the surface molecules of tumor cells in the 3-dimensional culture systems.

Effects of Pseudomonas Aeruginosa Infection and Mechanical Trauma to the Sinus Mucosa on Polyp Formation in the Rabbit Maxillary Sinuses

The aim of this study is to develop an animal model of polyps that is more suitable for further polyp studies by semiquantitatively analyzing the effects of Pseudomonas aeruginosa infection and/or mechanical trauma to the sinus mucosa, based on the epithelial rupture theory, on polyp formation in the rabbit maxillary sinuses. The natural ostia were occluded in 30 Pasturellafree New Zealand white rabbits. All rabbits were divided into three groups according to the following modes of manipulation on the right maxillary sinus: inoculation with P. aeruginosa (group A), brushing of the sinus mucosa (group B), and inoculation with P. aeruginosa accompanied by brushing of the mucosa (group C). The left maxillary sinuses were used as the control. After four weeks, macroscopic polyps and light microscopic polyps and/or polypoid mucosa were semiquantitatively analyzed. The number of macroscopic polyps per sinus was significantly larger in groups A (1.0 polyps) and C (1.3 polyps) than in group B (0.0 polyps). Microscopic examination revealed significantly higher levels of polyps and/or polypoid mucosa in groups A and C than in group B. The results of this study suggest that a rabbit model of polyps using P. aeruginosa is suitable for further polyp studies and that induction of this type of model needs no mechanical trauma to the sinus mucosa.

Significance of Caloric Test in Reversed Position / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Caloric nystagmus has been known since a century ago, and the thermal convection theory proposed by Barany has been widely accepted. Gravity plays an important role in thermal convection. In 1984, caloric nystagmus was reported in weightless space environments and although the response was weak, the nystagmus was found to occur in the same direction as the earth. This implies that factors other than thermal convection might participate in the caloric nystagmus. MATERIALS AND METHODS: Using 50 normal ears as subjects, this study compared the responses of conventional caloric test and reversed caloric test, which places the plane of the lateral semicircular canal upside down. RESULTS: The direction of the nystagmus was reversed, and the maximal slow phase velocity was decreased compared to that of the normal caloric test. CONCLUSION: The reversed direction of the nystagmus observed in this study basically supports the theory by Barany, however, the differences that are noted implicate that other factors with a certain direction maybe involved.

Dose-response Relationship of Morphologic Changes by Cisplatin and Radiation in Guinea Pig Cochleas / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Cisplatin or radiation have been widely used in the treatment of patients with head and neck cancers. However, their adverse effects such as ototoxicity and nephrotoxicity are serious considerations. This study was aimed to establish a dose-dependent response in an animal model, with the hope of contributing to research for prevention of ototoxicity in cancer patients treated with radiation or chemotherapy. MATERIAL AND METHODS: Three different doses (4, 8, 12 mg/kg) of intraperitoneal cisplatin and radiation (17, 23, 33 Gy) were administered to guinea pigs. RESULTS: After 8 days, the temporal bones were prepared for scanning electron microscopic examination. The cochlear hair cells, especially outer hair cells in the third row, were severely damaged in the cisplatin groups and irradiation groups and these damages were related to the dose administered. The main abnormalities were the deletion or distortion of stereocilia of the hair cells and the loss of stiffness. CONCLUSION: A dose-dependent response relationship established in this study will provide as a useful reference for other researches for the prevention of ototoxicity by cisplatin and radiation.

Preventive Effect of Fosfomycin on Cisplatin Induced Ototoxicity in Cochlea of Guinea Pig / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The use of cisplatin as a therapeutic drug in malignant neoplasm is known to have associated side effects such as nephrotoxicity and ototoxicity. Although the nephrotoxic effect of this drug can be somewhat decreased by use of the hydration method, prevention of the ototoxic effect, which is known to induce irreversible change on the cochlea, has not been well established. The purose of this study is to evaluate the preventive effect of fosfomycin in cisplatin induced ototoxicity. METHODS: Fosfomycin was used to reduce the ototoxic effects of cisplatin, and its efficacies were evaluated anatomically as well as physiologically. Anatomically, a histologic study of cochleas was carried out by scanning electro-microscopy, and physiologically, cochlear microphonics and compound action potentials were studied in guinea pigs. RESULTS: Protection against distortion and loss of outer hair cells in the basal turn of cochlea caused by cisplatin was found to be statistically significant in the groups injected with fosfomycin. CONCLUSION: Fosfomycin was found to be effective in providing protection against cisplatin induced ototoxicity.

Anatomical Relationship of the Anterior Ethmoid Canal to the Anterior Skull Base: A Computed Tomographic Analysis on the Types of the Fovea Ethmoidalis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: As the anterior ethmoid canal (AEC) provides a good surgical landmark and its injury may result in serious complications, the anatomical relationship of the AEC to the anterior skull base (ASB) should be evaluated preoperatively. Despite some studies on the ASB, studies analyzing this anatomical relationship and the types of the fovea ethmoidalis (FE) on computed tomography (CT) are rare. The aim of this study is to better understand this anatomical relationship by determining the frequency of each type of the FE and distances between anatomical structures on the CT scans with our new classification. MATERIALS AND METHOD: Four hundred sides of the FE were analyzed from the preoperative coronal CT scans of 200 chronic sinusitis patients (100 males and 100 females, aged 20 to 59 years). The FE was classified into 4 types (I: non-separated type, II: partially separated type, III: completely separated type, IV: unidentifiable type) and 2 subtypes (A: developed medial cranial wall, B: undeveloped medial cranial wall). Heights of the medial cranial wall (a), the AEC (b), and the ethmoid roof (c) were measured on the CT image. RESULTS: Frequencies of the types I-IV were 48.0% (IA: 25.2%, IB: 22.8%), 19.3% (IIA: 4.3%, IIB: 15.0%), 29.5% (IIIA: 29.5%, IIIB: 0%), and 3.2%, respectively. The medial cranial wall of type IIIA was significantly longer than those of the other types, and the AEC of type IIIA was in a significantly lower position than those of the other types. CONCLUSION: On the CT scans, we found the AEC in 96.8% and type IIIA in nearly 30% of all types of the FE. Sinus surgery should be performed only after preoperative evaluation of these anatomical relationship on the CT scans under close scrutiny. For the type IIIA, surgery should be performed with utmost care due to high risk of injury to the AEC and the medial cranial wall.

Effects of Mechanical Trauma to the Sinus Mucosa on Polyp Formation in Induction of Maxillary Sinusitis in Rabbits by Streptococcus Pneumoniae / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Pathogenesis, definition, and treatment of sinonasal polyps remain uncertain. To elucidate them, many studies on polyps have been made. However, recently reported studies on polyps using animal models seldom provided comparative data on polyp formation in various conditions. The aim of this study is to develop an animal model of polyps which is more suitable for further polyp studies. We attempted a semiquantitative analysis on the effects of mechnical trauma to the sinus mucosa on formation of polyps and polypoid mucosa in duction of rabbit maxillary sinusitis by Streptococcus pneumoniae and compared the prevalences of polyps under the different conditions. MATERIALS AND METHODS: The natural ostia of both sinuses were occluded in 10 Pasturella-free New Zealand white rabbits. Both sinuses were inoculated with S. pneumoniae, without brushing the mucosa in the left maxillary sinuses (control group) and with brushing in the right sinuses (experimental group). After four weeks, all sinuses were re-opened. Macroscopic polyp and light microscopic polyps and/or polypoid mucosa were semiquantitatively analyzed and each prevalence was compared between the two groups. RESULTS: The number of macroscopic polyps per sinus was significantly larger in the experimental group (1.1 polyps) than that in the control group (0.1 polyps). Microscopic examination revealed significantly more polyps and/or polypoid mucosa in the experimental group than in the control group. CONCLUSIONS: Our results suggest that mechanically traumatizing the sinus mucosa, such as brushing, is more helpful to polyp formation when a rabbit model of polyps is to be induced by S. pneumoniae.