Clinical Outcomes of Clipping and Coil Embolization for Ruptured Intracranial Aneurysms Categorized by Region and Hospital Size: A Nationwide Cohort Study in Korea.

BACKGROUND: To analyze the outcomes of clipping and coiling for ruptured intracranial aneurysms (RIAs) based on data from the National Health Insurance Service in South Korea, with a focus on variations according to region and hospital size. METHODS: This study analyzed the one-year mortality rates for patients with RIAs who underwent clipping or coiling in 2018. Coiling was further categorized into non-stent assisted coiling (NSAC) and stent assisted coiling (SAC). Hospitals were classified as tertiary referral general hospitals (TRGHs), general hospitals (GHs), or semi-general hospitals (sGHs) based on size. South Korea's administrative districts were divided into 15 regions for analysis. RESULTS: In 2018, there were 2,194 (33.1%) clipping procedures (TRGH, 985; GH, 827; sGH, 382) and 4,431 (66.9%) coiling procedures (TRGH, 1,642; GH, 2076; sGH, 713) performed for RIAs treatment. Among hospitals performing more than 20 treatments, the one-year mortality rates following clipping or coiling were 11.2% and 16.0%, respectively, with no significant difference observed. However, there was a significant difference in one-year mortality between NSAC and SAC (14.3% vs. 19.5%, P = 0.034), with clipping also showing significantly lower mortality compared to SAC (P = 0.019). No significant differences in other treatment modalities were observed according to hospital size, but clipping at TRGHs had significantly lower mortality than at GHs (P = 0.042). While no significant correlation was found between the number of treatments and outcomes at GHs, at TRGHs, a higher volume of clipping procedures was significantly associated with lower total mortality (P = 0.023) and mortality after clipping (P = 0.022). CONCLUSION: Using Korea NHIS data, mortality rates for RIAs showed no significant variation by hospital size due to coiling's prevalence. However, differences in clipping outcomes by hospital size and volume in TRGH highlight the need for national efforts to improve clipping skills and standardization. Additionally, the higher mortality rate with SAC emphasizes the importance of precise indications for its application.

Relationship between in-stent restenosis following carotid artery stenting and platelet reactivity to clopidogrel.

OBJECTIVE: To analyze the relationship between in-stent restenosis (ISR) following carotid artery stenting (CAS) and platelet clopidogrel reactivity confirmed by the P2Y12 reaction unit (PRU) and inhibition rate (IR). METHODS: We retrospectively analyzed 171 patients who underwent CAS with extracranial carotid stenosis from January 2016 to December 2019. Dual antiplatelet therapy with 100 mg aspirin and 75 mg clopidogrel was started ≥5 days before CAS. Clopidogrel resistance was measured with the PRU and IR the day before CAS. The ISR degree was classified into R1, R2, and R3 (moderate to severe luminal stenosis of ≥50% or occlusion) by carotid CT angiography after 24-30 months. The degree of quantitative association between platelet reactivity and ISR R3 was determined by the receiver operating characteristic curve method. The optimal cut-off values of PRU and IR were derived using the maximum Youden index. RESULTS: There were 33 R3 degrees of ISR (19.3%) and nine ipsilateral ischemic strokes (5.3%). The PRU and IR were different between R1+R2 degrees (176.4±50.1, 27.5±18.7%) and R3 degree (247.5±55.0, 10.3±13.4%) (P<0.001). The areas under the curves of PRU and IR were 0.841 and 0.781, and the optimal cut-off values were 220.0 and 14.5%, respectively. Multivariate logistic regression analysis showed that PRU ≥220 and IR ≤14.5% were significant predictive factors for ISR R3 (P<0.001 and P=0.017, respectively). ISR R3 was independently associated with ipsilateral ischemic stroke after CAS (P=0.012). CONCLUSIONS: High PRU (≥220) and low IR (≤14.5%) are related to ISR R3 following CAS, which may cause ipsilateral ischemic stroke.

Optimal blood pressure for stroke prevention in healthy adults below 65 years: A nationwide 10-year observational study.

BACKGROUND: There have been few reports on the preventative value of intensive blood pressure (BP) management for stroke since the American College of Cardiology/American Heart Association (ACC/AHA) announced the new criteria for hypertension (HTN) in 2017. This study aimed to identify optimal BP for prevention of stroke in healthy adults under 65 years. METHODS: We conducted a 10-year observational study on the risk of stroke, subclassified as hemorrhagic stroke (HS) or ischemic stroke (IS), according to BP categories (low-normal BP, high-normal BP, elevated BP, stage 1 HTN, and stage 2 HTN) using the National Health Insurance Service Database. RESULTS: In 2008, a health checkup was conducted for a total of 8,327,751 participants, and 949,551 of them enrolled in this study. The risk of HS increased from stage 2 HTN (adjusted hazard ratio [AHR], 3.036 [95 % confidence interval [CI], 2.159-4.252]) in men to stage 1 HTN (AHR, 2.972; 95 % CI, 2.256-3.897) in women. The risk of IS increased in both men (AHR, 1.404 [95 % CI, 1.164-1.693]) and women (AHR, 2.012 [95 % CI, 1.603-2.526]) with stage 1 HTN. The overall risk of stroke increased in men (AHR, 1.386; [95 % CI, 1.180-1.629]) and women (AHR, 2.363 [95 % CI, 1.973-2.830]) with stage 1 HTN. CONCLUSION: This study underscores the importance of maintaining BP below Stage 1 HTN to prevent stroke in healthy adults aged below 65 years. These findings highlight the significance of the new HTN guidelines established by the ACC/AHA in 2017.

Transcanal endoscopic myringoplasty with butterfly dermal allograft.

OBJECTIVE: Tympanic membrane perforation (TMP) is a common cause of visits to the otolaryngology clinic. For decades, various surgical methods and various grafts have been used to treat TMP. This study aimed to compare the efficacy of butterfly dermal allograft (BDA) and fat myringoplasty for the treatment of TMP. STUDY DESIGN: A retrospective case-control study. SETTING: Tertiary referral center. METHODS: We retrospectively analyzed 40 patients who underwent BDA (n = 20) and fat myringoplasty (n = 20) for TMP performed by a single surgeon between January 2019 and December 2021. The hearing outcomes, graft success rate, complications, operation time, and hospital stay were recorded and compared between the two groups. Hearing outcomes were determined by pure-tone audiometry. RESULTS: There was no significant difference between the BDA and fat groups regarding demographic characteristics. There was no significant difference in the pre and postoperative air conduction and bone conduction thresholds, or air-bone gap values between the two groups. A significant audiologic improvement was observed in both groups (p < 0.05), but there was no significant difference in the degree of hearing gain between the two groups. In terms of recurrence of tympanic membrane perforation, postoperative otorrhea, and discomfort symptoms; however, there was no significant difference between the groups (p > 0.05). The operation time and hospital stay were shorter in the BDA group than in the fat group (p < 0.05). CONCLUSION: BDA myringoplasty is as safe and medically efficacious as fat myringoplasty and shortens the operation time and hospital stay.

Safety and Efficacy of Intraoperative Doppler Sonography-Assisted Cervical Pedicle Screw Fixation-A Retrospective Comparison with Conventional Pedicle Screw Implantation.

STUDY DESIGN: A Retrospective Cohort Study. OBJECTIVE: To introduce a new Doppler sonography-assisted pedicle screw fixation technique that enables vertebral artery (VA) monitoring during surgery and compares the accuracies of Doppler sonography-assisted cervical pedicle screw fixation and the conventional technique. METHODS: This retrospective study was performed on 164 consecutive patients that underwent pedicle-based screw fixation from C2 to C6 between January 2013 and August 2020. Surgery was performed without intraoperative Doppler sonography in 84 cases (the Control group) or with intraoperative Doppler sonography in 80 cases (the Doppler group). Proper positioning of pedicle screws was graded, and the incidences of VA injury and screw breach in the Control and Doppler groups were compared. RESULTS: Three hundred and ninety-nine screws were placed in the 164 patients (Doppler, 186 screws; Control, 213 screws). The percentages of well-positioned screws in the two groups were significantly different (Doppler, 97.8%; Control, 85.0%). There were two cases of VA injury in the Control group, an incidence of 2.4%, but no case in the Doppler group. CONCLUSION: Doppler sonography can be used intraoperatively to help guide the trajectory of the cervical pedicle screw insertion. It can detect the VA inside the screw trajectory and may reduce the risk of VA injury during cervical pedicle screw fixation.

Treatment results for congenital cholesteatoma using transcanal endoscopic ear surgery.

PURPOSE: Transcanal endoscopic ear surgery for congenital cholesteatoma provides a smaller incision and better visibility than conventional surgical microscope ear surgery. We aimed to evaluate the treatment results of transcanal endoscopic ear surgery in ameliorating the recurrence and post-operative complications of pediatric congenital cholesteatoma. MATERIALS AND METHODS: A retrospective chart review was conducted on patients with congenital cholesteatoma who underwent transcanal endoscopic ear surgery at a tertiary referral medical center from January 2012 to December 2020. We categorized the patients into two groups according to the presence of remnant cholesteatoma and compared their characteristics. RESULTS: This study included 46 patients (32 males and 14 females; 46 ears). The mean age was 3.0 ± 2.6 (1-17) years. Congenital cholesteatoma was predominantly located in the anterior-superior quadrant (63.0 %), and ossicular involvement was confirmed in six cases. The mean cholesteatoma size identified by temporal bone computed tomography was 3.9 ± 2.0 (1.2-13) mm. Seven cases had remnant cholesteatoma lesions (15.2 %); four improved after revision surgery, and three were followed up without immediate further intervention. Postoperative complications (e.g., tympanic membrane perforation, retraction) were observed in 10 cases. Comparative evaluations of various characteristics after categorizing the participants into residual and non-residual lesion groups revealed no significant differences. CONCLUSIONS: Consequently, transcanal endoscopic ear surgery can be considered an effective and safe operation for treating congenital cholesteatoma in the pediatric population with no serious side effects. Further large-scale research with hearing test results should be conducted meticulously as a follow-up to this study.

Clinical Outcomes of Clipping and Coiling in Elderly Patients with Unruptured Cerebral Aneurysms: a National Cohort Study in Korea.

BACKGROUND: We aimed to analyze outcomes of clipping and coiling in treating unruptured intracranial aneurysms (UIAs) in elderly patients and to identify the age at which perioperative risk increases based on national cohort data in South Korea. METHODS: The incidence of perioperative intracranial hemorrhage (ICRH), perioperative cerebral infarction (CI), mortality, and moderate to severe disability data of the patients who underwent coiling or clipping for UIAs were retrieved. Estimated breakpoint (EBP) was calculated to identify the age at which the risk of treatment increases. RESULTS: A total of 38,207 patients were treated for UIAs. Among these, 22,093 (57.8%) patients underwent coiling and 16,114 (42.2%) patients underwent clipping. The incidence of ICRH, requiring a secondary operation, within 3 months in patients ≥ 65 years that underwent coiling and clipping was 1.13% and 4.81%, respectively, and that of both groups assessed were significantly higher in patients ≥ 75 years (coiling, P = 0.013, relative risk (RR) 1.81; clipping, P = 0.015) than younger patients. The incidence of CI within 3 months in patients aged ≥ 65 was 13.90% and 9.19% in the coiling and clipping groups, respectively. The incidence of CI after coiling in patients aged ≥ 75 years (P < 0.001, RR 1.96) and after clipping in patients aged ≥ 70 years (P < 0.001, RR 1.76) was significantly higher than that in younger patients. The mortality rates within 1 year in patients with perioperative ICRH or CI were 2.41% and 3.39% for coiling and clipping groups, respectively, in patients ≥ 65. These rates increased significantly at age 70 in the coiling group and at age 75 for the clipping group (P = 0.012 and P < 0.001, respectively). CONCLUSION: The risk of treatment increases with age, and this risk increases dramatically in patients aged ≥ 70 years. Therefore, the treatment decisions in patients aged ≥ 70 years should be made with utmost care.

Two newly identified Haematococcus strains efficiently accumulated radioactive cesium over higher astaxanthin production.

In this study, we investigated the morphological, genomic and bioaccumulation characteristics of two isolated Haematococcus strains (namely Goyang and Sogang), which were newly discovered in South Korea. Morphological analysis revealed that the isolated strains were unicellular and bi-flagellated green microalgae that formed thickened walls at the palmelloid or red-cyst phase. Phylogenetic analysis of 18S rRNA and rbcL gDNA sequences demonstrated that both strains were taxonomically related to the genus Haematococcus. The two strains showed growth pattern that was similar to a typical Haematococcus strain, and accumulated astaxanthin within 48 h of exposure to intensive light. Both red-cyst cells effectively removed radioactive cesium to more than 50% within 48 h from low-level cesium-contaminated water of 5 Bq/ml concentration. The cesium-accumulation mechanism is largely associated with the replacement of cellular potassium in thick cell walls during biouptake, and the cesium-removal rate highly depends on the corresponding astaxanthin accumulation involving the potassium-transporting protein (P-type ATPase).

Automatic Concrete Damage Recognition Using Multi-Level Attention Convolutional Neural Network.

There has been an increase in the deterioration of buildings and infrastructure in dense urban regions, and several defects in the structures are being exposed. To ensure the effective diagnosis of building conditions, vision-based automatic damage recognition techniques have been developed. However, conventional image processing techniques have some limitations in real-world situations owing to their manual feature extraction approach. To overcome these limitations, a convolutional neural network-based image recognition technique was adopted in this study, and a convolution-based concrete multi-damage recognition neural network (CMDnet) was developed. The image datasets consisted of 1981 types of concrete surface damages, including surface cracks, rebar exposure and delamination, as well as intact. Furthermore, it was experimentally demonstrated that the proposed model could accurately classify the damage types. The results obtained in this study reveal that the proposed model can recognize the different damage types from digital images of the surfaces of concrete structures. The trained CMDnet demonstrated a damage-detection accuracy of 98.9%. Moreover, the proposed model could be applied in automatic damage detection networks to achieve superior performance with regard to concrete surface damage detection and recognition, as well as accelerating efficient damage identification during the diagnosis of deteriorating structures used in civil engineering applications.

Evaluation and Surgical Planning for Craniovertebral Junction Deformity.

Craniovertebral junction (CVJ) deformity is a challenging pathology that can result in progressive deformity, myelopathy, severe neck pain, and functional disability, such as difficulty swallowing. Surgical management of CVJ deformity is complex for anatomical reasons; given the discreet relationships involved in the surrounding neurovascular structures and intricate biochemical issues, access to this region is relatively difficult. Evaluation of the reducibility, CVJ alignment, and direction of the mechanical compression may determine surgical strategy. If CVJ deformity is reducible, posterior in situ fixation may be a viable solution. If the deformity is rigid and the C1-2 facet is fixed, osteotomy may be necessary to make the C1-2 facet joint reducible. C1-2 facet release with vertical reduction technique could be useful, especially when the C1-2 facet joint is the primary pathology of CVJ kyphotic deformity or basilar invagination. The indications for transoral surgery are becoming as narrow as a treatment for CVJ deformity. In this article, we will discuss CVJ alignment and various strategies for the management of CVJ deformity and possible ways to prevent complications and improve surgical outcomes.

Surgical treatment of preauricular sinus in children: Temporalis muscle fascia anchoring suture.

OBJECTIVE: The aim of this study was to find an effective treatment method for preauricular sinus (PAS) in the pediatric population. We also investigated if the prognosis of treatment differed according to the location of the PAS. METHODS: From May 2015 to April 2020, a retrospective chart review was conducted on pediatric patients who underwent surgical excision of PAS at a tertiary referral medical center. Patients were divided into classical and variant groups according to the location of the PAS. The recurrence and postoperative complications, along with the preoperative history, were confirmed through medical chart review. RESULTS: A total of 88 patients (112 ears) were included in the study (n = 77 in the classical group and n = 11 in the variant group). The mean age of the patient was 6.5 years, and there were 48 males and 40 females. To reduce recurrence after surgical treatment, a temporalis muscle fascia anchoring suture was used in combination with preoperative pit dye staining, probe use, and surgical microscopy. The overall recurrence rate was 2.4% (2 cases), and postoperative minor complications were chronic pain (4.5%, n = 4), minor skin inflammation (10.2%, n = 9), and subcutaneous suture knot discomfort (13.6%, n = 12). Between the classical and variant groups, no clinical differences such as recurrence rate or complication rate were found, except for the long hospitalization period in the variant group (p = 0.043). CONCLUSIONS: The use of a temporalis muscle fascia anchoring suture in combination with pit dye staining, probe use, and surgical microscopy in pediatric patients with PAS showed relatively low recurrence and complication rates compared to what has been previously reported in the literature. PAS in the variant position did not affect prognosis.

The value of CT, MRI, and PET-CT in detecting retropharyngeal lymph node metastasis of head and neck squamous cell carcinoma.

BACKGROUND: The diagnostic accuracies of the imaging studies should be clearly acknowledged in managing head and neck cancer patients; however, the accuracies of preoperative imaging studies in detecting retropharyngeal lymph node (RPLN) metastasis are still not clarified. This study was to evaluate diagnostic accuracies of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT) in detecting RPLN metastasis of head and neck squamous cell carcinomas. METHODS: For 123 patients who had performed RPLN dissection during the surgery of their squamous cell carcinoma of the head and neck, preoperative CT, MRI, and/or PET-CT were reviewed for RPLN metastasis in a blinded fashion by one experienced radiologist. Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of each imaging modality were assessed, by comparing with the histopathologic findings of the resected RPLNs that served as the standard of reference. RESULTS: RPLNs were pathologically positive for metastasis in 43 of the 123 patients (35%). Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in detecting metastasis to RPLN were 65, 94, 85, 83, and 84% for CT; 74, 94, 87, 87 and 87% for MRI; 83, 93, 89, 89 and 89% for PET-CT, respectively. When all the three imaging modalities were considered together (n = 74), they offered sensitivity of 90%, specificity of 91%, positive predictive value of 87%, negative predictive value of 93%, and accuracy of 91%. CONCLUSIONS: The preoperative imaging studies offered relatively high specificity rates, but rather low sensitivity rates. The three imaging modalities altogether increased diagnostic accuracies, which highlights the potential of the three studies when used altogether can minimize missed diagnoses of RPLN metastasis.

Enhancement of Drought Tolerance in Cucumber Plants by Natural Carbon Materials.

Stress induced by climate change is a widespread and global phenomenon. Unexpected drought stress has a substantial effect on the growth and productivity of valuable crops. The effects of carbon materials on living organisms in response to abiotic stresses remain poorly understood. In this study, we proposed a new method for enhancing drought tolerance in cucumber (Cucumis sativus L.) using carbon nanotubes and natural carbon materials called shungite, which can be easily mixed into any soil. We analyzed the phenotype and physiological changes in cucumber plants grown under conditions of drought stress. Shungite-treated cucumber plants were healthier, with dark green leaves, than control plants when watering was withheld for 21 days. Furthermore, compared with the control cucumber group, in the shungite-treated plants, the monodehydroascorbate content of the leaf, which is a representative marker of oxidative damage, was 66% lower. In addition, major scavenger units of reactive oxygen species and related drought stress marker genes were significantly upregulated. These results indicate that successive pretreatment of soil with low-cost natural carbon material improved the tolerance of cucumber plants to drought stress.

Biosorption of radioactive cesium from contaminated water by microalgae Haematococcus pluvialis and Chlorella vulgaris.

The biosorption properties of water-soluble radioactive cesium (137Cs) by microalga Haematococcus pluvialis were evaluated with different cell conditions, and its cesium-uptake rate was compared with that by other microalgae, Chlorella vulgaris and Anabaena sp. Photo-induced H. pluvialis red cyst rapidly removed radioactive cesium from the solution by bioaccumulation. We showed that the effectiveness of 137Cs uptake is dependent on the specific cell condition of even the same microalgal species. While the H. pluvialis red cyst removed almost 95% of the soluble 137Cs in 48 h, both H. pluvialis intermediate cells and C. vulgaris showed 90% uptake efficiency of 137Cs with slow uptake rate. The energy dispersive spectrometer data demonstrated that the cesium uptake acceleration by inducing astaxanthin in H. pluvialis red cyst involves the cesium accumulation through the potassium transport channel. The long-term monitoring experiments of the cesium uptake showed that only 40% of 137Cs remained in collapsed H. pluvialis cell fragments after 12 months.

Parasellar Extension Grades and Surgical Extent in Endoscopic Endonasal Transsphenoidal Surgery for Pituitary Adenomas : A Single Surgeon's Consecutive Series with the Aspects of Reliability and Clinical Validity.

OBJECTIVE: The inter-rater reliability of the modified Knosp's classification was measured before the analysis. The clinical validity of the parasellar extension grading system was evaluated by investigating the extents of resection and complication rates among the grades in the endoscopic endonasal transsphenoidal surgery (EETS) for pituitary adenomas. METHODS: From November 2008 to August 2015, of the 286 patients who underwent EETS by the senior author, 208 were pituitary adenoma cases (146 non-functioning pituitary adenomas, 10 adrenocorticotropic hormone-secreting adenomas, 31 growth hormone-secreting adenomas, 17 prolactin-secreting adenomas, and 4 thyroid-stimulating hormone-secreting adenomas; 23 microadenomas, 174 macroadenomas, and 11 giant adenomas). Two neurosurgeons and a neuroradiologist independently measured the degree of parasellar extension on the preoperative sellar MRI according to the modified Knosp's classification. Inter-rater reliability was statistically assessed by measuring the intraclass correlation coefficient. The extents of resection were evaluated by comparison of the pre- and post-operative MR images; the neurovascular complications were assessed by reviewing the patients' medical records. The extent of resection was measured in each parasellar extension grade; thereafter, their statistical differences were calculated. RESULTS: The intraclass correlation coefficient value of reliability across the three raters amounted to 0.862. The gross total removal (GTR) rates achieved in each grade were 70.0, 69.8, 62.9, 21.4, 37.5, and 4.3% in Grades 0, 1, 2, 3A, 3B, and 4, respectively. A significant difference in the extent of resection was observed only between Grades 2 and 3A. In addition, significantly higher complication rates were observed in the groups above Grade 3A. CONCLUSION: Although the modified Knosp's classification system appears to be complex, its inter-rater reliability proves to be excellent. Regarding the clinical validity of the parasellar extension grading system, Grades 3A, 3B, and 4 have a negative predictive value for the GTR rate, with higher complication rates.

Acute Paraplegia as a Result of Hemorrhagic Spinal Ependymoma Masked by Spinal Anesthesia: Case Report and Review of Literature.

Ependymomas are the most common intramedullary spinal cord tumors in adults. Although a hemorrhage within spinal ependymoma on imaging studies is not uncommon, it has rarely been reported to bea cause of acute neurological deficit. In the present report, we describe a case of a 24-year-old female patient who developed acute paraplegia as a result of hemorrhagic spinal ependymoma immediately after a cesarean delivery under spinal regional anesthesia. We review the literature of hemorrhagic spinal ependymomas presenting with acute neurological deficit and discuss the most appropriate treatment for a good neurological recovery.

The Production of High Purity Phycocyanin by Spirulina platensis Using Light-Emitting Diodes Based Two-Stage Cultivation.

Phycocyanin is a photosynthetic pigment found in photosynthetic cyanobacteria, cryptophytes, and red algae. In general, production of phycocyanin depends mainly on the light conditions during the cultivation period, and purification of phycocyanin requires expensive and complex procedures. In this study, we propose a new two-stage cultivation method to maximize the quantitative content and purity of phycocyanin obtained from Spirulina platensis using red and blue light-emitting diodes (LEDs) under different light intensities. In the first stage, Spirulina was cultured under a combination of red and blue LEDs to obtain the fast growth rate until reaching an absorbance of 1.4-1.6 at 680 nm. Next, blue LEDs were used to enhance the concentration and purity of the phycocyanin in Spirulina. Two weeks of the two-stage cultivation of Spirulina yielded 1.28 mg mL(-1) phycocyanin with the purity of 2.7 (OD620/OD280).

Clinical outcome and prognostic factors after salvage surgery for isolated regional squamous cell carcinoma recurrences.

BACKGROUND: The purpose of this study was to evaluate the outcome and predictive factors for salvage surgery of isolated regional recurrences of head and neck squamous cell carcinoma. METHODS: A retrospective study was conducted with 55 patients who were treated with surgery-based treatment. RESULTS: The 5-year overall survival (OS) and disease-free survival (DFS) rates were 61.8% and 60%, respectively. Extracapsular spread (ECS) was an independent factor associated with worse disease-specific survival. The patients who had advanced N classification, ECS, and in-field recurrence had a significantly worse OS rate, whereas those with an initial DFS time of 6 months or more experienced better outcomes. CONCLUSION: Salvage surgery for isolated regional recurrence resulted in an acceptable oncologic outcome and mortality. Successful surgical salvage is most probable in late recurrence (≥6 months) patients with recurrent N1 stage tumors (no evidence of ECS) outside of the previous treatment field.

Photosynthetic biomineralization of radioactive Sr via microalgal CO2 absorption.

Water-soluble radiostrontium ((90)Sr) was efficiently removed as a carbonate form through microalgal photosynthetic process. The immobilization of soluble (90)Sr radionuclide and production of highly-precipitable radio-strontianite ((90)SrCO3) biomineral are achieved by using Chlorella vulgaris, and the biologically induced mineralization drastically decreased the (90)Sr radioactivity in water to make the highest (90)Sr removal ever reported. The high-resolution microscopy revealed that the short-term removal of soluble (90)Sr by C. vulgaris was attributable to the rapid and selective carbonation of (90)Sr together with the consumption of dissolved CO2 during photosynthesis. A small amount of carbonate in water could act as Sr(2+) sinks through the particular ability of the microalga to make the carbonate mineral of Sr stabilized firmly at the surface site.

Clinical characteristics of spontaneous cholesteatoma of the external auditory canal in children comparing with cholesteatoma in adults.

The purpose of this study was to investigate the characteristics of external auditory canal cholesteatoma (EACC) in children through evaluation of the clinical and radiologic features as well as treatment outcomes. The clinical records were retrospectively reviewed for children under 15 years of age diagnosed with spontaneous EACC between March 2004 and December 2011. The clinical data of adults diagnosed with spontaneous EACC during the same period were evaluated to compare with EACC in children. Eight patients (3 males and 5 females) with pediatric EACC and 18 patients (7 males and 11 females, 20 ears) with adult EACC were included within the boundary of the study. The mean ages were 12.4 years (age range 9-15) for pediatric EACC and 49.8 years (age range 29-79) for adult EACC patients. Follow-up periods ranged from 8 to 86 months (mean 32.5 ± 8.62) in pediatric EACC and from 6 to 72 months (mean 22.2 ± 5.36) in adult EACC. Pediatric EACC, showed involvement most commonly in the posterior wall, while the inferior wall was most commonly involved in adult EACC. Pediatric EACC tended to show a more focal involvement and was not as extensive as adult EACC. Extension into the adjacent structures was similar in both groups, but bony destruction was more common in the adult group. Two children and eight adult patients were treated with surgery, but four adult cases needed more extensive surgical treatment because their disease was widely spread to included areas such as the mastoid segment of facial nerve and the temporomandibular joint. Six pediatric cases treated with conservative management showed no progression of disease on physical examination at the last visit, but two cases of adults progressed and required canaloplasty. Pediatric EACC shows less aggressive behavior compared to adult EACC. Adequate management may work better in pediatric than in adult EACC, even though the treatment modality is conservative management.