Prediction of the efficacy of proton-pump inhibitors in patients with contact granuloma using 24-hour combined dual channel pH/impedance monitoring.

OBJECTIVES: We aimed to evaluate the treatment outcomes of proton-pump inhibitors (PPIs) in patients with contact granuloma (CG) and to investigate the parameters of 24 h combined dual channel pH/impedance (24 h pH/MII) monitoring, which are reliable for predicting the response to PPI of CG patients. METHODS: We reviewed the medical records of patients with CG who had been treated with PPIs and had completed more than 6 months of follow-up. We classified the patients into two groups (cured vs. persistent), according to their PPI treatment outcomes. Reflux events were categorized into three groups based on pharyngeal pH during reflux: 1) acid reflux (pH < 4), 2) weak acid reflux (4 < pH < 7), and 3) weak alkaline reflux (pH >7), as detected by a proximal probe. We compared the results of 24h-pH/MII between the two groups and used receiver operating characteristic curve (ROC) analysis to determine the cutoff values of significant parameters for predicting responses to PPIs. RESULTS: Among 22 patients who completed at least 6 months of PPI treatment and follow-up, weak acid reflux events were more frequently observed in persistent group than in the cured group (p = 0.046), and the proportion of weak acid reflux was also higher in the persistent group (p = 0.031) than in the cured group. Reliable parameters predictive of a poor response to PPIs were a number of weak acid reflux events ≥ 11 (area under the curve [AUC], 0.775; p = 0.03) and a proportion of weak acid reflux events ≥ 56.7 % (AUC, 0.763; p = 0.038) in ROC analyses. CONCLUSION: Weak acid reflux was identified as a significant factor associated with the treatment outcomes of PPIs in patients with CG. A number of weak acid reflux events ≥ 11 is considered to be the most reliable predictor of a poor response to PPIs in patients with CG.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery.

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

A Rat Model for Oral Mucositis Induced by a Single Administration of 5-Fluorouracil.

BACKGROUND/AIM: This study aimed to develop a reliable chemotherapy-induced oral mucositis (CIOM) rat model by intraperitoneally administering a single dosage of 5-fluorouracil (5-FU) combined with a chemical stimulus. MATERIALS AND METHODS: The 5-FU dosage for CIOM development was determined by the survival rate of rats administrated 160 mg/kg, 200 mg/kg, and 240 mg/kg of 5-FU. Thirty rats were assigned to normal control (NC) and three experimental groups: i) ulcer formation without 5-FU administration (PBS/U+), ii) 5-FU administration without ulcer formation (5-FU/U-), and iii) ulcer formation after 5-FU administration (5-FU/U+). White blood cell count and weight were measured at the day of 5-FU administration (D0), ulcer formation (D2), and two days after ulcer formation (D4). The oral mucosa for histologic evaluations was obtained two (D4) and five days (D7) after ulcer formation. RESULTS: The 5-FU dosage for CIOM development was 200 mg/kg. White blood cell count (WBC) counts and weight of rats were significantly lower in 5-FU/U- (WBC, p<0.001; weight, p=0.002) and 5-FU/U+ (WBC, p<0.001; weight, p<0.001) groups compared to those in the NC group at D4. The number of Ki-67 positive cells in the oral epithelium was lower in 5-FU/U+ group compared to that in NC (p<0.001) and PBS/U+ (p=0.047) groups at D7. CONCLUSION: Single administration of 200 mg/kg of 5-FU combined with a chemical stimulus can lead to an immune-suppressive status, failure of weight gain, and impairment of epithelium regeneration as observed in a CIOM rat model.

Changes in the Laryngeal Mucosa After Thyroid Surgery: A Rat Model.

BACKGROUND/AIM: Thyroidectomy can cause various airway symptoms affecting the quality of life. We investigated the changes in extracellular matrix (ECM) composition and markers for inflammation and microcirculation of laryngeal mucosa. MATERIALS AND METHODS: Sixty Sprague-Dawley rats were categorized into control and three surgical groups based on the extent of surgeries, 1) flap elevation (FE) group, 2) thyroid and trachea exposure (TE) group, and 3) thyroid isthmectomy (TI) group. We analyzed the expression of TGF-ß1, VEGFR-3, CD31, and MMP- 9 in relation to the inflammatory and microcirculatory changes in the lamina propria on postoperative days (PODs) 3, 7, and 21. ECM composition of hyaluronic acid (HA) and collagen in the subglottic area (SA) was also evaluated. RESULTS: All parameters increased in surgical groups at each postoperative phase except collagen deposition. On POD 3, TGF-ß1 expression and SA increased in relation to the surgical extent and decreased over time, but more than the control in all surgical groups on POD 21. Surgical groups had more HA and less collagen composition, causing a higher HA to collagen ratio in relation to the surgical extent. VEGFR-3 and CD31 expression increased with time at all postoperative phases according to the surgical extent. Expression of MMP-9 increased in TI groups compared to TE and FE groups on POD 7 and POD 21. CONCLUSION: This study demonstrated that thyroid surgery exposing the thyroid and trachea induces an increase in the SA with a higher HA and lesser collagen composition. Furthermore, the markers for acute inflammation and microcirculation with tissue remodeling increased in the laryngeal mucosa.

Application of a strip design to monitor the viability of buried radial forearm free flap in East Asians: A case series study.

OBJECTIVES: The objectives of this study were to evaluate the reliability of a strip design as a monitoring flap in buried flap and to investigate whether strip design of radial forearm free flap (RFFF) could affect donor site morbidity in East Asian. METHODS: Patients with externalized flap in buried RFFF were consecutively included in this study. For cases with mucosal defect repair, a skin strip with a 1.5 cm width was proximally positioned to the primary flap along with the pedicle. Compared to a mucosal defect, a skin strip was distally positioned overlying the pedicle (near the wrist) when the flap was used for reinforcing the facial contour, reconstructing sacrificed facial nerve, or reanimating facial expression. The externalized flap formation was performed after completion of anastomoses of vessels. Monitoring results of flap failure using an externalized monitoring flap and additional morbidity of donor site were evaluated. RESULTS: Nine patients were included in this study. Although there were two cases of pharyngeal fistula due to mucosal necrosis of resection margin, transferred RFFF was viable in all cases. The externalized flap provided reliable monitoring for the buried RFFF without a case of necrosis even in two cases with a partial detachment of septocutaneous branches between the radial artery and the designed skin strip. There was no false - positive case. Therefore, the sensitivity and positive predictive value of the externalized monitoring flap were 100%. All defects of radial forearm caused by skin strip harvest were also primarily closed without an additional skin graft. CONCLUSION: A strip design for externalized monitoring flap in RFFF can facilitate an easier creation of externalized monitoring flap in cases with buried RFFF without additional morbidity at the donor site compared to a conventional techniques.

Restoration of Homeostasis in the Tracheal Mucosa After Thyroid Surgery in a Rat Model.

BACKGROUND/AIM: This study aimed to investigate the process of homeostatic restoration in the tracheal mucosa (TM) after thyroid surgery. MATERIALS AND METHODS: Fifty-four rats were divided into normal controls (NC) and three experimental groups: (i) flap elevation (FE), (ii) thyroid exposure (TE), and (iii) thyroid isthmusectomy (TI). Expression of mRNA and proteins of key factors regulating homeostasis were evaluated in the TM obtained 3, 7, and 21 days after thyroid surgery. RESULTS: Increased mRNA expression of transforming growth factor-ß1 (TGF-ß1), hypoxia-inducible factor-1α (HIF-1α), and matrix metalloproteinase-9 (MMP-9) were observed 21 days after thyroid surgery in all experimental groups compared to that of NC group. CONCLUSION: Thyroid surgery leads to an actual increase of TGF-ß1, HIF-1α, and MMP-9 expression in the TM. This increased expression of key regulators of homeostatic restoration in the TM lasts for a considerable period of time after surgery, especially if the extent of surgery increased.

Effects of allergic rhinitis on the progression and recovery of acute otitis media in a mouse model.

OBJECTIVES: The objective of this study was to evaluate the effects of allergic rhinitis (AR) on the development, progression, and recovery of acute otitis media (OM) in an animal model and investigate the secondary effects of bacterial infection. METHODS: BALB/c mice were divided into four groups: AR + OM, AR, OM, and control groups. AR + OM and AR groups were sensitized with ovalbumin (OVA) and alum and then challenged intranasally with OVA. Phosphate-buffered saline (PBS) was administered to the OM and control groups the same number of times. After AR induction, OM was induced by surgical inoculation of non-typeable Haemophilus influenza (NTHi) into the middle ear (ME) cavity of the mice in the AR + OM and OM groups. PBS was injected into the bulla in the AR and control groups. Each group was subdivided into sets of six mice, one for each of the four time points (0, 2, 7, and 10 days post-bacterial inoculation), at which point the mice were euthanized and ME and nasal cavity mucosa were obtained and evaluated. The occurrence of OM and the ME mucosa thickness were evaluated and compared among the four groups. Tissue expression of interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α) in infected ME mucosa was assessed by immunohistochemical staining. We also investigated IgE, IL-4, and IL-5 in the nasal mucosa. RESULTS: Most of the ears showed OM on post-inoculation day 2 in both AR + OM and OM groups. In the AR + OM group, 58.3% of ears still had OM on post-inoculation day 10, while only 16.7% of the OM group had OM. The ME mucosa of all groups increased, and the AR + OM group exhibited the thickest mucosa. The OM group showed peak thickness on post-inoculation day 2 and then decreased, whereas the ME mucosa thickness of the AR + OM group continued to increase to day 7. In the OM group, the expression of IL-1ß, IL-6, and TNF-α in the ME also increased significantly, peaking on post-inoculation day 2, and then gradually decreased. In the AR + OM group, the expression of these proteins increased until day 7 and then decreased. The IgE and Th2 response (IL-4 and IL-5) cytokines were expressed at higher levels in the AR + OM and AR groups than in the OM and control groups. CONCLUSION: The inflammatory reaction to NTHi was more intense and lasted longer in the allergic group, which indicates that AR affects the progression and subsequent recovery of acute bacterial OM.

Changes in Tracheal Respiratory Mucosa After Thyroidectomy: A Rat Model.

BACKGROUND/AIM: This study aimed to investigate changes in the tracheal mucosa after thyroidectomy, that can be a cause of post-thyroidectomy discomfort. MATERIALS AND METHODS: Forty rats were divided into normal controls and 3 surgical groups: (i) thyroid isthmectomy with cauterization, (ii) isthmectomy by a cold instrument without hemostasis, and (iii) sham (exposure of the trachea and thyroid gland without thyroidectomy by dissection through pretracheal fascia). Animals were euthanized at 1 and 4 weeks. Mucosal edema and glandular hyperplasia were measured. Mucin production and basal cell activities were evaluated by mucin 5AC (MUC5AC) and keratin 5 (KRT5) using immunofluorescence staining. RESULTS: Larger mucosal areas were observed in all surgical groups at 1 and 4 weeks. More submucosal glandular hyperplasia was noted in the group with isthmectomy without hemostasis. MUC5AC and KRT5 expressions were significantly higher in the surgical groups. CONCLUSION: The tracheal mucosa may change after surgery, which could explain postoperative discomfort after thyroidectomy.

Effects of Amniotic Membrane Extract on the Hyperplastic Response of the Middle Ear Mucosa in a Bacterially-Induced Otitis Media Rat Model: A Preliminary Study.

OBJECTIVES: Human amniotic membrane extract (AME) is known to contain numerous bioactive factors and anti-inflammatory substances. However, the anti-inflammatory effects of AME on the middle ear (ME) mucosa are unclear. This study assessed the effects of AME on the growth of the ME mucosa in response to bacterially-induced otitis media (OM). METHODS: OM was induced by inoculating nontypeable Haemophilus influenzae (NTHi) into the ME cavity of rats. ME mucosal explants were cultured in AME concentrations of 0, 5, 10, or 50 µg/mL. The area of explant outgrowth was measured in culture and analyzed at 1, 3, 5, and 7 days after explantation. The expression of Ki-67, mucin 5AC (MUC5AC), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) in the explants was also evaluated using quantitative polymerase chain reaction (PCR) and immunocytochemistry (ICC). RESULTS: The NTHi-induced ME mucosa growth increased gradually over the 7-day culture period in all explants at different AME concentrations. There was a trend for mucosal growth inhibition at higher concentrations of AME, although the growth was not significantly different among the groups until day 5. The ME mucosal explants treated with the 50 µg/mL concentration of AME showed significantly suppressed growth on postexplantation day 7 compared with other explants on the same day. PCR and ICC staining revealed that the expression of Ki-67, MUC5AC, TNF-α, and IL-10 further decreased in the explants with higher concentrations of AME than in those with lower concentrations of AME. CONCLUSION: Our results showed that higher concentrations of AME reduced the mucosal proliferative response in bacterial OM in rats. These findings provide evidence that AME has an influence on the inflammatory and proliferative responses to NTHi infection in ME mucosa.

Prediction of anterior commissure exposure of vocal folds prior to laryngeal microscopic surgery: Parameters reflecting occipito-atlanto-axial complex extension capacity.

OBJECTIVE: The purpose of this prospective study was to identify preoperative predictors of unstable exposure of vocal folds with focus on the anterior commissure (AC) prior to Laryngeal Microscopic Surgery. METHODS AND MATERIALS: Patients were classified into four groups based on the degree of AC exposure during Laryngeal Microscopic Surgery, and for the analysis, these groups were subdivided into unstable exposure and stable exposure subgroups depending on whether external manipulation was required to achieve AC exposure. Correlation of the degree of AC exposure with demographics, physical measurements, and anatomical measurements taken using landmarks in simple radiograph were evaluated. Receiver operating characteristic curve analysis was used to determine optimal cutoff values to predict unstable AC exposure. RESULTS: Fifty-nine patients were included in the analyses. Thyroid-mandible angle (TMA) in the extended position, thyroid-mental distance (TMD) ratio, and TMA difference in the neutral and extended positions were significantly correlated with the degree of AC exposure. However, only a TMD ratio of <1.25 reliably predicted unstable AC exposure. CONCLUSIONS: TMD ratio of <1.25 reliably predicted unstable AC exposure. If there is no increase of the distance between the thyroid notch and the mental prominence (TMD) more than 25% on neck extension, the probability of getting stable exposure of the anterior commissure is low.

Prognostic value of the posterior cricoarytenoid muscle atrophy in computerized tomography scans for unilateral vocal fold paralysis recovery.

OBJECTIVES: To evaluate the prognostic value of the posterior cricoarytenoid (PCA) muscle atrophy observed on neck computed tomography (CT) in patients with unilateral vocal fold paralysis. METHODS: CT images of 87 subjects with unilateral vocal fold paralysis (UVFP) were evaluated to analyze the PCA muscle atrophy and to measure the severity of the PCA muscle atrophy in semi-quantitative manner. The grading of the PCA muscle atrophy was compared with the recruitment pattern of laryngeal electromyography (LEMG) and restoration of vocal fold movement. RESULTS: The PCA muscle was identifiable on CT in 73 subjects. Using the PCA muscle atrophy as an indicator of UVFP, we correctly predicted the paralysis in 69 (94.5%). Grade of the PCA muscle atrophy is significantly correlated with recruitment pattern of LEMG. If the positive result is defined as the PCA muscle showed moderate to severe degree of atrophy, we could predict the persistent UVFP in 88% of patients. CONCLUSIONS: PCA muscle atrophy identified on CT scan in patients with UVFP, is associated with low rates of return of mobility in the affected vocal fold.

Comparison of Treatment Outcomes for T3 Glottic Squamous Cell Carcinoma: A Meta-Analysis.

OBJECTIVES: This study compared the survival outcomes, local control rate, and laryngeal preservation rate of various treatment strategies in the treatment of T3 squamous cell carcinoma of the glottis using proportional meta-analyses. METHODS: Twenty-five retrospective case-series studies were included in these analyses. Treatment strategies were classified as total laryngectomy (TL), open partial laryngectomy (PL), transoral laser microsurgery (TLM), chemo-radiation therapy (CRT), and radiation therapy (RT) alone. RESULTS: The overall survival rate and disease-specific survival rate among laryngeal preservation treatments did not differ from the overall survival rate of TL. However, the local control rate was lower with RT than TL and PL, and laryngeal preservation rates of TLM and CRT were higher than RT alone. CONCLUSION: Consideration of preservation of laryngeal function is necessary when treating T3 glottic squamous cell carcinoma. PL, TLM, and, CRT are considered more appropriate initial laryngeal preservation strategies if available.

Clinical outcomes after local anesthesia with monitored anesthesia care during thyroidectomy and selective neck dissection: a randomized study.

Although thyroidectomy under local anesthesia with monitored anesthesia care (LA-MAC) has been reported, reports of neck dissections beyond level VI under LA-MAC in patients with thyroid cancer are rare. We aimed to analyze clinical data and patient satisfaction levels during thyroidectomy and selective neck dissection by comparing LA-MAC and general anesthesia (GA) in adult patients undergoing these surgeries for thyroid cancer. The 60 enrolled patients comprised 50 patients that underwent thyroidectomy and 10 that underwent selective neck dissection; 30 underwent thyroidectomy (n = 25) or selective neck dissection (n = 5) under LA-MAC and 30 (matched patients) underwent thyroidectomy (n = 25) or selective neck dissection (n = 5) under GA. Complaints of postoperative nausea, vomiting, throat discomfort, and voice changes were significantly fewer in the LA-MAC group than in the GA group. Postoperative pain, odynophagia, dyspnea, and patient satisfaction levels were not significantly different between groups. In the thyroidectomy group, postoperative nausea, vomiting, throat discomfort, and voice changes were less common with LA-MAC, whereas postoperative pain, odynophagia, dyspnea, and patient satisfaction levels were similar for both anesthesia methods. The selective neck dissection group showed no differences between the two anesthesia methods. No postoperative complications were reported in all patients. Our results suggest that LA-MAC can be routinely used for select cases of thyroidectomy and is feasible for selective neck dissection beyond level VI with regard to postoperative discomfort, patient satisfaction levels, and safety. However, further investigations are necessary to clarify these findings.

A Case of Nuclear Protein in Testis Midline Carcinoma Arising From the Submandibular Gland Duct in a Pregnant Patient.

This report describes the first reported case of a nuclear protein in testis midline carcinoma (NMC) arising from the submandibular gland (SMG) duct in a pregnant woman. A 29-year-old pregnant woman presented with a left-side mass in the floor of the mouth. An NMC arising from the SMG duct was confirmed by excisional biopsy examination. Intensive treatment, including surgery and chemotherapy, was provided without termination of the pregnancy. Additional chemotherapy and radiotherapy were provided after delivery. The treatment was successful. Neither the patient nor her infant had any complications and the patient remained disease free 20 months after her initial surgery. This report describes the successful diagnosis and treatment of a rare presentation of an NMC of the SMG duct in a pregnant woman.

Antitumor effect of CXCR4 antagonist AMD3100 on the tumorigenic cell line of BHP10-3 papillary thyroid cancer cells.

BACKGROUND: A tumorigenic cell line (BHP10-3M) derived from nontumorigenic papillary thyroid carcinoma (PTC) cells (BHP10-3) having rearranged during transfection (RET)/PTC1 gene rearrangement might have a higher expression of CXCR4, either quantitatively or functionally. The authors also postulated that CXCR4-mediated invasion or tumorigenesis could be blocked by CXCR4 antagonists, including AMD3100. METHODS: The expression of CXCR4 in BHP10-3 and BHP10-3M cells was assessed using immunoblot analysis, flow cytometry, and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). The effect of AMD3100 on BHP10-3 and BHP10-3M cell lines was evaluated using cell proliferation assay, invasion assay, and tumor growth experiment in nude mice. RESULTS: Immunoblotting, flow cytometry, and quantitative RT-PCR proved that BHP10-3M cells expressed a higher level of CXCR4 than BHP10-3 cells. Although blocking CXCR4 with AMD3100 did not suppress cell proliferation in both cell lines from 1 ng/mL to 100 ng/mL concentration, AMD3100 suppressed invasion of BHP10-3M cells in vitro in a dose-dependent manner. At higher concentrations from 10(3) ng/mL to 10(5) ng/mL, the proliferation of BHP10-3M cells was inhibited more strongly by AMD3100 than that of BHP10-3 cells. Intraperitoneal injection of AMD3100 inhibited tumor formation by BHP10-3M cells in the thyroid of nude mice. CONCLUSION: A tumorigenic cell line (BHP10-3M) of PTC showed higher expression of CXCR4 quantitatively and functionally than a nontumorigenic cell line (BHP10-3). The CXCR4 antagonist (AMD3100) showed a significant antitumor effect on the tumorigenic cell line of PTC BHP10-3 cells both in vitro and in vivo. CXCR4 antagonist can be expected to have an adjuvant role in the management of PTC. © 2016 Wiley Periodicals, Inc. Head Neck, 2016 © 2016 Wiley Periodicals, Inc. Head Neck 38: First-1486, 2016.

Treatment of intraoral ranulas with micromarsupialization: clinical outcomes and safety from a phase II clinical trial.

BACKGROUND: Micromarsupialization of an oral ranula has been introduced to clinical practice. However, the technical feasibility, indications, and safety of the procedure were not fully studied. In this study, we report the results of a prospective phase II clinical trial to evaluate the clinical outcomes. METHODS: Twenty patients diagnosed with oral ranula were enrolled in this trial. The ranulas were confirmed by oral examination and CT scans. We implemented micromarsupialization on the patients after receiving their consent. We evaluated the clinical outcomes and complications related to this procedure for longer than a 12-month period. RESULTS: All patients showed resolution after the first micromarsupialization, after which 5 patients developed a recurrence that required revision micromarsupialization. Six months later, only 2 patients showed recurrence, requiring resection of the ranula and sublingual gland. CONCLUSION: Micromarsupialization can be a very effective and safe approach as an initial treatment for intraoral ranula.

Petrosquamosal sinus: clinical characteristics based on radiologic and operative findings.

OBJECTIVE: Petrosquamosal sinus (PSS) is an embryonic emissary vein of the temporal bone connecting the intracranial and extracranial venous networks, which is present in some variants of venous cerebral drainage. The aim of the present study was to analyze 20 cases of PSS and to present its clinical characteristics and implications. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: By reviewing retrospective medical records and TBCT findings, a total of 20 PSS cases were found. Based on the shapes of PSS demonstrated on TBCT, PSS was classified into tortuous and straight types. The course and thickness of PSS were also investigated. The average thicknesses of PSS between tortuous and straight types were compared. RESULTS: The mean age of the patients was 54.1 ± 16.2 years. The study group consisted of 7 male (35.0%) and 13 female (65.0%) patients. Eleven cases were found on the right side and 8 cases on the left side. The mean diameter of the bony canal that PSS courses on TBCT was 2.57 ± 0.88 mm. Its maximal and minimal diameters were 4.2 and 0.7 mm. The average diameter of tortuous type PSSs (3.04 ± 0.75 mm) was significantly larger compared with that of straight-type PSSs (2.09 ± 0.76 mm) (p < 0.05). CONCLUSION: Preoperative identification of PSS using TBCT may be important for safe mastoid surgery. The presence of PSS should be identified with thorough examination of radiographic findings before mastoid surgery.

Bone formation of middle ear cavity using biphasic calcium phosphate lyophilized with Escherichia coli-derived recombinant human bone morphogenetic protein 2 using animal model.

OBJECTIVE: The aim of the study was to analyze the value of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2) coated biphasic calcium phosphate (BCP) for the obliteration of middle ear bone defect after mastoid surgery. METHODS: Twenty-four specific pathogen-free Sprague-Dawley rats were randomly assigned to the BCP group (n=12) and BCP-ErhBMP-2 group (n=12; in which BCP scaffold of the granular type was coated with ErhBMP-2). In both groups, BCP scaffold was used to surgically fill the middle ear bulla. New bone formation was evaluated by measuring bone density (%) after 4 and 8 weeks in all rats in both groups. RESULTS: At 4 weeks, new bone was visible at the periphery and center of the middle ear cavity in both groups. In the BCP group, a moderate amount of fibrous tissue had infiltrated into the interspace of the scaffolds. New bone almost totally filled the interspace in the BCP-ErhBMP-2 group. At 8 weeks, copious new bone formation had occurred. Histometric measurements showed that bone density in the BCP group was smaller than in the BCP-ErhBMP-2 group at 4 weeks (25.10% and 38.43%, respectively; p<0.05) and 8 weeks (25.54% and 34.18%, respectively; p<0.05). CONCLUSIONS: New bone formation was greater in the presence of BCP-ErhBMP-2 scaffolds. ErhBMP-2 coated BCP scaffolds is a potentially useful material for middle ear obliteration after mastoidectomy.