Enhancing optical isolator performance in nonreciprocal waveguide arrays.

We investigate the operation of optical isolators based on magneto-optics waveguide arrays beyond the coupled mode analysis. Semi-vectorial beam propagation simulations demonstrate that evanescent tail coupling and the effects of radiation are responsible for degrading the device's performance. Our analysis suggests that these effects can be mitigated when the array size is scaled up. In addition, we propose the use of radiation blockers in order to offset some of these effects, and we show that they provide a dramatic improvement in performance. Finally, we also study the robustness of the system with respect to fabrication tolerances using the coupled mode theory. We show that small, random variations in the system's parameters tend to average out as the number of optical guiding channels increases.

Modified frailty index (mFI): is it a predictor for early postoperative complications in arthroplasty surgery?

OBJECTIVE: It has been demonstrated that the modified frailty index (mFI) is a powerful and effective tool in the prediction of perioperative risk in many surgical fields. In many previous studies, mFI has been found to be successful in prediction of perioperative adverse effects. The aim of this study was to determine whether the mFI can be a predictor for early postoperative complications in arthroplasty surgery. PATIENTS AND METHODS: 145 patients aged 45-85 undergoing primary or revision total knee and hip arthroplasty were included in this prospective study. mFI was calculated in all patients, and patients included in the current study were grouped as "Frail" (n=42) and "Nonfrail" (n=103) patients according to modified frailty index values. Postoperative complications (myocardial infarction, cardiac arrest, pulmonary embolism, septic shock, postoperative dialysis requirement, cerebrovascular event, reintubation, prolonged mechanical ventilation, surgical wound complications), duration of hospitalization, requirement for intensive care unit (ICU) admission and rehospitalization and 30-day mortality were recorded and the correlation between mFI and these parameters were evaluated. RESULTS: The mean age was 67.58±9.35 years, and 72.4% of the patients were female. The percentage of frail patients in the current study was 28.9%. The percentage of ASA-1, ASA-2, and ASA-3 patients was 17.2%, 57.2%, and 25.5%, respectively. The rate of ICU admission, MI, septic shock, postoperative dialysis requirement, prolonged MV requirement, hospital readmission, and 30-day mortality were 45.2%, 14.3%, 16.7%, 16.7%, 14.3%, 11.9%, and 16.7%, respectively in the frail group and were 7.8%, 1%, 1.9%, 2.9, 1.9% and 3.9%, respectively in the nonfrail group. Advanced age, male gender, high ASA score and prolonged duration of surgery were found to be predictive factors for postoperative complications. Advanced age, high ASA score and prolonged duration of surgery were found to be predictive factors for ICU admission. Advanced age, male gender and high ASA score were found to be strong predictors of 30-day mortality. CONCLUSIONS: mFI was found to be a strong predictor for postoperative complications and mortality. It is an easy, reliable, and simple method to evaluate frailty during the preoperative period. CLINICAL TRIAL REGISTRATION NUMBER: NCT05424575.

Preserving T2 in thoracic sympathicotomy for palmar hyperhidrosis: less tissue trauma, same effectiveness.

BACKGROUND: The aim of this study was to compare two different sympathicotomy procedures for primary hyperhidrosis in terms of compensatory sweating, complications, safety and effectiveness. METHODS: The data of 78 consecutive patients who underwent bilateral endoscopic thoracic sympathicotomy (156 laterals) for palmar hyperhidrosis between January 2005 and September 2009 were studied retrospectively. The first 29 consecutive patients were treated with a T2-3 sympathicotomy (Group A). After November 2007, all patients (49 patients) were treated with a T3 sympathicotomy alone (Group B). The chest tubes were always removed after checking for pneumothorax with roentgenography. All patients were followed up and evaluated for results, side effects, complications, and satisfaction levels. The differences between the two groups were analyzed. RESULTS: The mean age of the 47 (60.2 %) female and 31 (39.8 %) male patients was 25.2 years. Horner's syndrome and pneumothorax was not detected in either group. The mean follow-up time was 20.82 months (6-52 months). Effectiveness of the procedure at the time of discharge and at follow-up was 100 % and 97.5 %, respectively. There was no significant difference between groups with regard to any analyzed parameter. CONCLUSION: This study demonstrates that preserving the T2 ganglion is safe, and does not compromise the effectiveness of the procedure. Sympathicotomy has the same success rate as sympathectomy, but requires significantly less dissection and results in less tissue trauma.

Prognostic factors for survival in patients with thymic epithelial tumors.

BACKGROUND: Aim of the study was to identify and evaluate the prognostic efficacy of standard clinicopathological factors of thymic epithelial tumors (TETs) for treatment-related outcomes. MATERIALS AND METHODS: All patients treated between 1993-2008 at Ege University Faculty of Medicine Departments of Radiation Oncology and Thoracic Surgery were reviewed retrospectively. RESULTS: Forty-seven patients with a median age of 51 (range: 24-72) were identified. Complete resection was performed in 23 (51.1%), incomplete resection with microscopic residues in 17 (37.8%), subtotal resection with gross residues in 2 (4.4%) and biopsy in 5 (11.1%) patients. Radiotherapy was administered to 39 (83%) patients. Median follow-up duration was 51 months (range: 3-168 months). Five-year local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS) rates were 93%, 90% and 85% for thymoma and 80%, 66% and 72% for thymic carcinoma patients, respectively. In multivariate analysis, the extent of resection was the only significant prognostic factor for OS (P = 0.001). CONCLUSIONS: The most important prognostic factor for overall survival was the extent of resection. Further studies with larger numbers of patients are required to confirm the prognostic factors and to obtain a better understanding of the biological behavior of TETs.

The effect of blood vessel invasion on prognosis of operated stage I non-small cell lung cancer patients.

OBJECTIVE: A retrospective study was conducted to identify the effect of blood vessel invasion on prognosis in surgically treated stage I non-small cell lung cancer patients. METHODS: A total of 71 consecutive patients who had undergone complete resection for stage I primary non-small cell lung cancer (NSCLC) between 1998 and 2007 were evaluated. All pathological specimens were examined for evidence of blood vessel invasion. The follow-up period was 5-118 months. Survival data were analyzed for all patients using the Kaplan-Meier test. RESULTS: There were 63 men and 8 women (mean age 59.2, age range 35-86). The most common tumor types were adenocarcinoma (35 patients, 49 %) and squamous cell carcinoma (26 patients, 37 %). Twenty-five patients (35 %) had stage IA disease, and 46 had (65 %) stage IB disease. In 13 cases (18 %) blood vessel invasion was demonstrated, whereas in the remaining 58 cases there was no evidence of vascular invasion. Minimum and maximum follow-up periods were 5 and 118 months respectively, with a mean of 41.76 +/- 27 months (median 33.5 months). Overall disease-free survival was 79.6 +/- 6.4 months: 38.3 +/- 12.0 months for the group with blood vessel invasion and 87.5 +/- 6.7 months for the remaining group. The difference between the two groups was statistically significant ( P < 0.003). Overall survival rate was 86.7 +/- 6.7 months: 44.5 +/- 11.3 months for blood vessel invasion group and 98.2 +/- 6.2 months for the remaining group. The difference between the two groups was statistically significant ( P < 0.001). CONCLUSION: Vascular invasion can be an important factor for predicting unfavorable prognosis in stage I NSCLC patients.

Ligasure vessel sealing system versus harmonic scalpel for sutureless nonanatomical pulmonary resections in a rabbit model. Which one is safer?

BACKGROUND: The safety and efficacy of the ligasure vessel sealing system (LVSS) and harmonic scalpel (HS) in sutureless nonanatomical lung resections were evaluated. METHODS: On twenty adult rabbit lungs, 1 x 1 cm wedge resections were performed under one-lung ventilation with both LVSS and HS. The air tightness and tissue damage caused by these different techniques were measured and compared. RESULTS: No statistically significant differences were found when the air tightness for both devices was compared after resection (p = 0.37). Tissue damage was obtained for LVSS, and the difference was statistically significant (p < 0.001). discussion: LVSS and HS can both be used for peripheral lung resections without any need of further intervention for securing the air tightness. LVSS was found safer by means of tissue damage when compared with HS in this experimental study.

Comparison of low-dose spinal anesthesia and single-shot femoral block combination with conventional dose spinal anesthesia in outpatient arthroscopic meniscus repair.

OBJECTIVE: In the current prospective, randomized study, we aimed to compare the effects of low dose selective spinal anesthesia with 5 mg of hyperbaric bupivacaine and single-shot femoral nerve block combination with conventional dose selective spinal anesthesia in terms of intraoperative anesthesia characteristics, block recovery characteristics, and postoperative analgesic consumption. PATIENTS AND METHODS: After obtaining institutional Ethics Committee approval, 52 ASA I-II patients aged 25-65, undergoing arthroscopic meniscus repair were randomly assigned to Group S (conventional dose selective spinal anesthesia with 10 mg bupivacaine) and Group FS (low-dose selective spinal anesthesia with 5mg bupivacaine +single-shot femoral block with 0.25% bupivacaine). Primary endpoints were time to reach T12 sensory block level, L2 regression, and complete motor block regression. Secondary endpoints were maximum sensory block level (MSBL); time to reach MSBL, time to first urination, time to first analgesic consumption and pain severity at the time of first mobilization. RESULTS: Demographic characteristics were similar in both groups (p > 0.05). MSBL and time to reach T12 sensory level were similar in both groups (p > 0.05). Time to reach L2 regression, complete motor block regression, and time to first micturition were significantly shorter; time to first analgesic consumption was significantly longer; and total analgesic consumption and severity of pain at time of first mobilization were significantly lower in Group FS (p < 0.05). CONCLUSIONS: The findings of the current study suggest that addition of single-shot femoral block to low dose spinal anesthesia could be an alternative to conventional dose spinal anesthesia in outpatient arthroscopic meniscus repair. CLINICAL TRIALS REGISTRATION NUMBER: NCT02322372.

Peritonsillar infiltration with levobupivacaine for posttonsillectomy pain relief: does concentration have any effect? A double-blind randomized controlled clinical study.

OBJECTIVE: Post-tonsillectomy pain is believed to be mediated by noxious stimulation of C-fiber afferents located in the peritonsillary space, and local anesthetic infiltration to this area may decrease pain by blocking the sensory pathways and thus preventing the nociceptive impulses. We aimed to compare the effects of different concentrations of preincisional peritonsillar levobupivacaine (0.25% and 0.5%) infiltration on postoperative pain and bleeding in a placebo-controlled design. PATIENTS AND METHODS: After obtaining Institutional Ethics Committee approval, 72 ASA I-II patients between 3 and 12 years of age, scheduled to undergo tonsillectomy were enrolled and randomly assigned to one of the three groups using the sealed envelope technique, as Group I (Control group), Group II, and Group III receiving preincisional bilateral peritonsillar infiltration with saline, 0.25% levobupivacaine and 0.5% levobupivacaine, respectively (3 mL to each tonsil). Pain, fever, dysphagia; nausea-vomiting and hemorrhage were evaluated at postoperative 0, 30, and 60 minutes and 2, 6, 12, and 24 hours. Oral paracetamol was administered at a dose of 15 mg/kg when FLACC score was > 4. The number of paracetamol administrations within the first 24 hours were recorded. RESULTS: The patients in Groups I, II and III defined pain (FLACC > 4) at a rate of 87%, 60.9%, and 54.2% within the postoperative first 24 hours, respectively. The total number of additional analgesic requirements was significantly low in Group II and III when compared with Group I. There was no difference between groups in terms of fever, dysphagia, nausea-vomiting, hemorrhage. CONCLUSIONS: Both concentrations (0.50% and 0.25%) of levobupivacaine were found to be equally safe and effective during preincisional peritonsillar infiltration in children. NCT number: 02322346.

Delayed onset malignant hyperthermia after sevoflurane.

Malignant hyperthermia is a hypermetabolic response to inhalation agents (such as halothane, sevoflurane, and desflurane), succinylcholine, vigorous exercise, and heat. Reactions develop more frequently in males than females (2 : 1). The classical signs of malignant hyperthermia are hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, muscle rigidity and rhabdomyolysis. In this case report, we present a case of delayed onset malignant hyperthermia-like reaction after the second exposure to sevoflurane.

Comparison of ropivacaine 0.2% and 0.25% with lidocaine 0.5% for intravenous regional anesthesia.

STUDY OBJECTIVE: To compare the anesthetic effects of two different concentrations and doses of ropivacaine (0.2% and 0.25%) with those of a conventional dose of lidocaine 0.5%. DESIGN: Prospective, randomized, double-blinded, clinical investigation. SETTING: Large metropolitan university hospital. PATIENTS: 66 adult ASA physical status I and II patients undergoing forearm and hand surgery. INTERVENTIONS: Patients were randomly allocated to three groups to receive intravenous regional anesthesia (IVRA). Study groups were: ropivacaine 0.2% (Group I, n = 22), ropivacaine 0.25% (Group II, n = 22), and lidocaine 0.5% (Group III, n = 22). MEASUREMENTS: Tourniquet tolerance times and regression of sensory analgesia were noted. Verbal numerical pain scores (VNS), cumulative analgesic consumption, and side effects were recorded during surgery and postanesthesia care unit (PACU). Time to first pain medication intake and number of patients receiving analgesics in the PACU were recorded. MAIN RESULTS: Additional tolerance times for the distal tourniquet were significantly higher in the ropivacaine 0.25% group than the other two groups. Regression of sensory anesthesia was fastest in the lidocaine group. During the PACU stay, VNSs were significantly lower in the first 20 minutes in the ropivacaine groups than the lidocaine group. Time to first intake of pain medication in the PACU was soonest in the lidocaine group. The number of patients given analgesics in the PACU was highest in the lidocaine group. The number of patients taking > two tablets of tramadol was significantly lowest in the ropivacaine 0.25% group. No serious side effects were observed in any study group. CONCLUSION: Longer tolerance times for the distal tourniquet, prolonged analgesia after tourniquet release, and lower analgesic requirements postoperatively make ropivacaine 0.2% and 0.25% an alternative to lidocaine for IVRA.

Comparison of the harmonic scalpel and the ultrasonic surgical aspirator in subsegmental lung resections: an experimental study.

BACKGROUND: In this study, we evaluated the effectiveness of two devices using ultrasonic energy for dissection of lung parenchyma in an experimental animal model by comparing the two methods with each other. METHODS: Twenty New Zealand rabbits were used. One-lung ventilation was obtained under direct vision and the left lung was collapsed. The rabbits were ventilated with pressure-controlled ventilation during the experiment, beginning with a pressure level of 10 cmH(2)O. After a 1 x 1-cm pulmonary wedge resection of part of the collapsed left lung using a harmonic scalpel (group A) or an ultrasonic surgical aspirator (group B), the left lung was inflated and the pressure level was increased by 5 cmH(2)O every five minutes. The pressure level which caused an air leak from the resection surface was recorded. The morphological damage to the lung parenchyma was evaluated under light microscopy. RESULTS: The mean value of airway pressure levels that resulted in an air leak from the resection surface was 32.5 +/- 9.2 cmH(2)O for group A and 24.5 +/- 2.9 cmH(2)O for group B, and the difference between the two groups was statistically significant. The mean level of coagulation necrosis was 558.6 +/- 380.8 microns (133 - 1064 microns) for group A. No tissue damage to pulmonary parenchyma was observed in group B. CONCLUSION: The harmonic scalpel can be safely used in peripheral lung resections without needing any other method to ensure hemostasis and air tightness. The ultrasonic surgical aspirator can be used for the dissection and resection of deeper lesions and preserves more lung tissue but requires additional interventions for control of the air leak from the resection surface.

Pulmonary aspiration of a two-unit bridge during a deep sleep.

Aspiration of teeth and dental restorations is a recognized, yet an infrequent happening in the literature. Main reasons of aspiration are maxillofacial trauma, dental treatment procedures or ethanol intoxication and dementia. The present case of a 2-unit bridge aspiration is however, not related with any trauma, dental procedure or systemic disease. A 37-year-old male patient had aspirated his bridge while sleeping and the bridge remained unidentified for 1 year despite the radiographic controls. He was then referred to the Chest Diseases Department of School of Medicine, Ege University and the radio-opaque object in the right intermediate bronchus was diagnosed to be an aspirated dental prosthesis. Subsequent to the failure of the rigid bronchoscopy, the patient was referred to the Thoracic Surgery Department and had to be operated for retrieval of the foreign body.