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.

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.

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).

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.

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.

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.

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.

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.

Pattern of cervical lymph node metastasis in medial wall pyriform sinus carcinoma.

OBJECTIVES/HYPOTHESIS: The aim of this study was to analyze the prevalence and distribution of histologic cervical lymph node metastases in medial wall pyriform sinus squamous cell carcinoma (SCC). STUDY DESIGN: Retrospective study of medical records. METHODS: We reviewed the medical records of 68 medial wall pyriform sinus SCC patients who underwent bilateral neck dissection for primary treatment with curative intent. Thirty-nine patients underwent central compartment neck dissection. Primary tumor was removed using conservative laryngeal surgery with partial pharyngectomy in 39 cases, near total/total laryngectomy with partial pharyngectomy in 24 cases, and total laryngopharyngectomy in five cases. RESULTS: The overall N(+) contralateral lymph nodes rate on pathology was 14.7%. The rate of contralateral occult cases was 5.2%. Advanced primary (T3-4) and nodal (N2b-3) disease, and primary lesion across the midline were correlated with contralateral nodal metastasis. Multivariate analysis revealed that a primary lesion across the midline was an independent factor for contralateral neck nodal metastasis. The rate of level VI node metastasis was 16.2%. The disease-specific survival rate was significantly different according to level VI node metastasis (71% vs. 40%). Pyriform sinus apex invasion and extralaryngeal spread were correlated with level VI nodal metastasis. Multivariate analysis revealed that pyriform sinus apex invasion was an independent factor for level VI nodal metastasis. CONCLUSIONS: Contralateral nodal metastasis was less frequent than expected. Bilateral neck dissection is mandatory for primary lesion across the midline. Ipsilateral level VI lymph node should be removed in pyriform sinus apex invasion cases. LEVEL OF EVIDENCE: 4.

Preparation of polymeric micelles consisting of poly(propylene glycol) and poly(caprolactone).

The ring-opening polymerization of epsilon-caprolactone (CL) was carried out with polypropylene glycol (PPG) as an initiator in the presence of the monomer activator HCl. Et2O to synthesize poly(epsilon-caprolactone)-poly(propyleneglycol)-poly(epsilon-caprolactone) (PCL-PPG-PCL) triblock copolymers with change of length PPG and PCL. The micelle formation of PCL-PPG-PCL triblock copolymers in an aqueous phase was confirmed by NMR, dynamic light scattering and fluorescence techniques. The critical micelle concentration (CMC) of the PCL-PPG-PCL triblock copolymers, determined from fluorescence measurements, was in range of 1.4 x 10(-3)-4.6 x 10(-3) mg/ml with dependence on block lengths of PPG and PCL. The partition equilibrium constant, K(v), which is an indicator of the hydrophobicity of the micelles of the PCL-PPG-PCL triblock copolymers in aqueous media, was also changed with dependence on length PPG and PCL. We confirmed that the PCL-PPG-PCL triblock copolymers formed micelles and hence may be potential hydrophobic drug carriers.

Synthesis and biological evaluation of 2,5-diaminobenzamide derivatives as anti-proliferating agents.

The screening of the chemical library for the anti-proliferative activity of the chemical library provided 2,5-diaminobenzamide as the initial hit. The confirmation and the optimization of hit were performed by synthesis followed by the evaluation of growth inhibitory activity against human cancer cell lines. The most active growth inhibitor showed IC(50) of 1.0 microM. The compound 7 increased not only sub-G1 population but also number of cells which are stained with Annexin V-FITC and 7-AAD, suggesting that compound 7 induced cell death is apoptosis.