¿Son las escalas de valoración de fragilidad superiores a la escala de valoración ASA en la predicción de complicaciones, estancia hospitalaria y readmisiones en prótesis total de rodilla? Un estudio comparativo entre pacientes octogenarios y septuagenarios / Are frailty scores superior to the ASA score in predicting complications, hospital stay, and readmissions in total knee replacement? A comparative study between octogenarian and septuagenarian patients

Antecedentes y objetivo: Las escalas de valoración de fragilidad no han sido estandarizadas para la evaluación prequirúrgica de pacientes sometidos a un reemplazo total de rodilla (RTR). El objetivo de este estudio fue comparar la eficacia de la escala de valoración de la Sociedad Americana de Anestesiología (ASA), el índice de comorbilidad de Charlson (ICC) y la escala simple de fragilidad (SSF) en la predicción de complicaciones, estancia hospitalaria, reingresos y mortalidad después del RTR electivo. Materiales y métodos: Estudiamos retrospectivamente a 448 pacientes que se sometieron a un RTR por artrosis en nuestra institución entre 2016 y 2019. Estos se dividieron en 2 grupos: grupo A (263 pacientes <80 años) y grupo B (185 pacientes >80 años). Todos fueron clasificados por escalas ASA, ICC y SSF. Resultados: El ICC fue mayor en el grupo B (mediana: 5 [RI: 4-6] vs. 4 [RI: 3-5]; p<0,001); sin embargo, no se asoció con un mayor número de complicaciones. Al realizar un análisis de regresión logística encontramos, para las complicaciones: OR SSF=0,67; ICC=1,11; ASA 3 y 4=0,89 y edad=1,04; mientras que para los reingresos: OR SSF=2,09; ICC=1,01; ASA 3 y 4=0,79 y edad=1. Conclusiones: Las escalas ICC y SSF demostraron no presentar diferencias a la escala ASA en la predicción de reingresos, complicaciones y estancia hospitalaria. Sin embargo, el SSF parece tener una mejor correlación en la predicción de la readmisión no planificada.(AU)

Background and objective: Frailty scores have not been standardized for the preoperative assessment of patients undergoing total knee replacement (TKR). The aim of this study was to compare the efficacy of the American Society of Anesthesiology (ASA) score, the Charlson comorbidity index (ICC) and the simple frailty score (SSF) in predicting complications, hospital stay, readmissions and mortality after elective TKR. Materials and methods: We retrospectively studied 448 patients who underwent TKR for osteoarthritis at our institution between 2016 and 2019. They were divided into two groups: Group A (263 patients, <80 years) and Group B (185 patients, >80 years).). All were classified by ASA, ICC and SSF scores. Results: The ICC was higher in Group B (median 5 [RI: 4-6] vs. 4 [RI: 3-5]; P<.001); however, it was not associated with a higher number of complications. When performing a logistic regression analysis we found, for complications: OR SSF=0.67, ICC=1.11; ASA 3 & 4=0.89 and age=1.04; while for readmissions: OR SSF=2.09; ICC=1.01; ASA 3 & 4=0.79 and age=1. Conclusions: The ICC and SSF scales showed no differences to the ASA scale in the prediction of readmissions, complications and hospital stay. However, the SSF seems to have a better correlation in predicting unplanned readmission.(AU)

[Translated article] Are frailty scores superior to the ASA score in predicting complications, hospital stay, and readmissions in total knee replacement? A comparative study between octogenarian and septuagenarian patients / ¿Son las escalas de valoración de fragilidad superiores a la escala de valoración ASA en la predicción de complicaciones, estancia hospitalaria y readmisiones en prótesis total de rodilla? Un estudio comparativo entre pacientes octogenarios y septuagenarios

Antecedentes y objetivo: Las escalas de valoración de fragilidad no han sido estandarizadas para la evaluación prequirúrgica de pacientes sometidos a un reemplazo total de rodilla (RTR). El objetivo de este estudio fue comparar la eficacia de la escala de valoración de la Sociedad Americana de Anestesiología (ASA), el índice de comorbilidad de Charlson (ICC) y la escala simple de fragilidad (SSF) en la predicción de complicaciones, estancia hospitalaria, reingresos y mortalidad después del RTR electivo. Materiales y métodos: Estudiamos retrospectivamente a 448 pacientes que se sometieron a un RTR por artrosis en nuestra institución entre 2016 y 2019. Estos se dividieron en 2 grupos: grupo A (263 pacientes <80 años) y grupo B (185 pacientes >80 años). Todos fueron clasificados por escalas ASA, ICC y SSF. Resultados: El ICC fue mayor en el grupo B (mediana: 5 [RI: 4-6] vs. 4 [RI: 3-5]; p<0,001); sin embargo, no se asoció con un mayor número de complicaciones. Al realizar un análisis de regresión logística encontramos, para las complicaciones: OR SSF=0,67; ICC=1,11; ASA 3 y 4=0,89 y edad=1,04; mientras que para los reingresos: OR SSF=2,09; ICC=1,01; ASA 3 y 4=0,79 y edad=1. Conclusiones: Las escalas ICC y SSF demostraron no presentar diferencias a la escala ASA en la predicción de reingresos, complicaciones y estancia hospitalaria. Sin embargo, el SSF parece tener una mejor correlación en la predicción de la readmisión no planificada.(AU)

Background and objective: Frailty scores have not been standardized for the preoperative assessment of patients undergoing total knee replacement (TKR). The aim of this study was to compare the efficacy of the American Society of Anesthesiology (ASA) score, the Charlson comorbidity index (ICC) and the simple frailty score (SSF) in predicting complications, hospital stay, readmissions and mortality after elective TKR. Materials and methods: We retrospectively studied 448 patients who underwent TKR for osteoarthritis at our institution between 2016 and 2019. They were divided into two groups: Group A (263 patients, <80 years) and Group B (185 patients, >80 years).). All were classified by ASA, ICC and SSF scores. Results: The ICC was higher in Group B (median 5 [RI: 4-6] vs. 4 [RI: 3-5]; P<.001); however, it was not associated with a higher number of complications. When performing a logistic regression analysis we found, for complications: OR SSF=0.67, ICC=1.11; ASA 3 & 4=0.89 and age=1.04; while for readmissions: OR SSF=2.09; ICC=1.01; ASA 3 & 4=0.79 and age=1. Conclusions: The ICC and SSF scales showed no differences to the ASA scale in the prediction of readmissions, complications and hospital stay. However, the SSF seems to have a better correlation in predicting unplanned readmission.(AU)

Incidence of vascular injury associated with knee arthroplasty: series of cases.

INTRODUCTION: The incidence of vascular injury associated with knee arthroplasty is scarce, but, when they occur, the consequences are serious. OBJECTIVES: Describe the incidence of vascular lesions in our center and evaluate time to diagnosis, resolution and follow-up. MATERIALS AND METHODS: Retrospective cohort during the 2010-2019 period of primary arthroplasties and knee revision. The incidence of vascular lesions and their demographic characteristics were analyzed. Type of lesion, diagnostic method and treatment were recorded. It was evaluated in distant follow-up of pain and functionality. RESULTS: 7.940 primary total knee arthroplasty and revision surgeries were recorded, and a report of 7 emergency cases for vascular lesions was also recorded, with an incidence of 0.088%. 3 vascular lesions were caused by direct laceration of the popliteal artery, 1 case of thrombosis of the popliteal artery and 3 cases of pseudoaneurysmal lesion of the superior genicular artery. Three vascular lesions that occurred in primary arthroplasty were immediately repaired by a vascular surgeon. Pseudoaneurysm lesions and thrombosis were resolved by angiographic procedure. DISCUSSION: Vascular complications around the knee are rare. Time to diagnosis and treatment is essential. Digital angiography is a diagnostic and therapeutic tool. There are various repair techniques, whether it's embolization, cauterization, stenting or endoprosthesis; therefore, digital angiography is a safe method with a low complication rate. CONCLUSION: The incidence of vascular lesions in knee arthroplasty in our center is very low. The cases were diagnosed and resolved early, without registering subsequent complications with good functional results in distant follow-up.

Are frailty scores superior to the ASA score in predicting complications, hospital stay, and readmissions in total knee replacement? A comparative study between octogenarian and septuagenarian patients. / ¿Son las escalas de valoración de fragilidad superiores a la escala de valoración ASA en la predicción de complicaciones, estancia hospitalaria y readmisiones en prótesis total de rodilla? Un estudio comparativo entre pacientes octogenarios y septuagenarios.

BACKGROUND AND OBJECTIVE: Frailty scores have not been standardized for the preoperative assessment of patients undergoing total knee replacement (TKR). The aim of this study was to compare the efficacy of the American Society of Anesthesiology (ASA) score, the Charlson comorbidity index (ICC) and the simple frailty score (SSF) in predicting complications, hospital stay, readmissions and mortality after elective TKR. MATERIALS AND METHODS: We retrospectively studied 448 patients who underwent TKR for osteoarthritis at our institution between 2016 and 2019. They were divided into two groups: Group A (263 patients, <80 years) and Group B (185 patients, >80 years).). All were classified by ASA, ICC and SSF scores. RESULTS: The ICC was higher in Group B (median 5 [RI: 4-6] vs. 4 [RI: 3-5]; P<.001); however, it was not associated with a higher number of complications. When performing a logistic regression analysis we found, for complications: OR SSF=0.67, ICC=1.11; ASA 3 & 4=0.89 and age=1.04; while for readmissions: OR SSF=2.09; ICC=1.01; ASA 3 & 4=0.79 and age=1. CONCLUSIONS: The ICC and SSF scales showed no differences to the ASA scale in the prediction of readmissions, complications and hospital stay. However, the SSF seems to have a better correlation in predicting unplanned readmission.

[Translated article] Are frailty scores superior to the ASA score in predicting complications, hospital stay, and readmissions in total knee replacement? A comparative study between octogenarian and septuagenarian patients.

BACKGROUND AND OBJECTIVE: Frailty scores have not been standardised for the preoperative assessment of patients undergoing total knee replacement (TKR). The aim of this study was to compare the efficacy of the American Society of Anesthesiology (ASA) score, the Charlson comorbidity index (ICC) and the simple frailty score (SSF) in predicting complications, hospital stay, readmissions and mortality after elective TKR. MATERIALS AND METHODS: We retrospectively studied 448 patients who underwent TKR for osteoarthritis at our institution between 2016 and 2019. They were divided into two groups: Group A (263 patients, <80 years) and Group B (185 patients, >80 years).). All were classified by ASA, ICC and SSF scores. RESULTS: The ICC was higher in Group B (median 5 [RI: 4-6] vs. 4 [RI: 3-5]; p<.001); however, it was not associated with a higher number of complications. When performing a logistic regression analysis we found, for complications: OR SSF=0.67; ICC=1.11; ASA 3 & 4=0.89 and age=1.04; while for readmissions: OR SSF=2.09; ICC=1.01; ASA 3 & 4=0.79 and age=1. CONCLUSIONS: The ICC and SSF scales showed no differences to the ASA scale in the prediction of readmissions, complications and hospital stay. However, the SSF seems to have a better correlation in predicting unplanned readmission.

La artroplastia total de rodilla en pacientes con enfermedad de Parkinson es efectiva. Evaluación funcional y análisis de complicaciones / Total knee arthroplasty is effective in patients with Parkinson's disease. Functional assessment and analysis of complications

Introducción: Gracias a las mejoras en el tratamiento médico de la enfermedad de Parkinson (EP), la esperanza de vida de estos pacientes ha aumentado. Los resultados generales después de la artroplastia total de rodilla (ATR) son controvertidos. Nuestro objetivo es analizar una serie de pacientes con EP, evaluando su estado clínico, resultados funcionales, complicaciones y tasas de supervivencia después de la ATR. Métodos: Se estudiaron retrospectivamente 31 pacientes con EP operados entre 2014-2020. La edad media fue de 71 años (DE±5,8). Había 16 pacientes mujeres. El seguimiento medio fue de 68,2 meses (DE±36). Se utilizó el Knee Scoring System (KSS) y la escala visual analógica (EVA) para la evaluación funcional. Se utilizó la escala modificada de Hoehn y Yahr para evaluar la gravedad de la EP. Se registraron todas las complicaciones y se realizaron curvas de supervivencia. Resultados: La evaluación media postoperatoria del KSS tuvo un aumento de 40 puntos (35 [DE±15] vs. 75 [DE±15] [p<0,001]). La media de EVA postoperatoria disminuyó 5 puntos (8 [DE±2] vs. 3 [DE±2] [p<0,001]). Trece pacientes informaron estar muy satisfechos, 13 estaban satisfechos y solo 5 estaban poco satisfechos. Siete pacientes sufrieron complicaciones quirúrgicas y 4 tuvieron inestabilidad rotuliana recurrente. Con una media de 68,2 meses de seguimiento, la tasa de supervivencia global fue del 93,5%. Al considerar el rescate rotuliano secundario como punto final, la tasa de supervivencia fue del 80,6%. Conclusiones: En este estudio, la ATR se asoció con muy buenos resultados funcionales en pacientes con EP. A una media de 68,2 meses de seguimiento, la ATR tuvo una buena supervivencia a corto plazo, siendo la inestabilidad rotuliana recurrente la complicación más frecuente. Aunque estos hallazgos confirman la efectividad de la ATR en esta población, se necesita una evaluación clínica exhaustiva y un enfoque multidisciplinario para disminuir la probabilidad de complicaciones.(AU)

Introduction: Thanks to improvements in the medical treatment of Parkinson's disease (PD), the life expectancy of these patients has increased, but the overall outcome after total knee arthroplasty (TKA) is controversial. We aim to analyse a series of patients with PD, evaluating their clinical status, functional results, complications and survival rates after TKA. Methods: We retrospectively studied 31 patients with PD operated between 2014-2020. The mean age was 71 years (SD±5.8). There were 16 female patients. The mean follow-up was 68.2 months (SD±36). We used the Knee Scoring System (KSS) and the Visual Analog Scale (VAS) for the functional evaluation. The Modified Hoehn and Yahr Scale was used to assess the severity of PD. All complications were recorded, and survival curves were performed. Results: The mean postoperative KSS evaluation had an increase of 40 points [35 (SD±15) vs 75 (SD±15) (P<.001)]. The mean postoperative VAS decreased 5 points [8 (SD±2) vs 3 (SD±2) (P<.001)]. Thirteen patients reported being very satisfied, 13 were satisfied, and only 5 were poorly satisfied. Seven patients suffered surgical complications, and 4 patients had recurrent patellar instability. At a mean 68.2 months follow-up, the overall survival rate was 93.5%. When considering the secondary patellar resurfacing as the endpoint, the survival rate was 80.6%. Conclusions: In this study, TKA was associated with excellent functional outcomes in patients with PD. At a mean 68.2 months follow-up, TKA had excellent survivorship in the short term, with recurrent patellar instability as the most common complication. Even though these findings confirm the effectiveness of TKA in this population, a thorough clinical evaluation and multidisciplinary approach are needed to decrease the likelihood of complications.(AU)

[Translated article] Total knee arthroplasty is effective in patients with Parkinson's disease. Functional assessment and analysis of complications / La artroplastia total de rodilla en pacientes con enfermedad de Parkinson es efectiva. Evaluación funcional y análisis de complicaciones

Introducción: Gracias a las mejoras en el tratamiento médico de la enfermedad de Parkinson (EP), la esperanza de vida de estos pacientes ha aumentado. Los resultados generales después de la artroplastia total de rodilla (ATR) son controvertidos. Nuestro objetivo es analizar una serie de pacientes con EP, evaluando su estado clínico, resultados funcionales, complicaciones y tasas de supervivencia después de la ATR. Métodos: Se estudiaron retrospectivamente 31 pacientes con EP operados entre 2014-2020. La edad media fue de 71 años (DE±5,8). Había 16 pacientes mujeres. El seguimiento medio fue de 68,2 meses (DE±36). Se utilizó el Knee Scoring System (KSS) y la escala visual analógica (EVA) para la evaluación funcional. Se utilizó la escala modificada de Hoehn y Yahr para evaluar la gravedad de la EP. Se registraron todas las complicaciones y se realizaron curvas de supervivencia. Resultados: La evaluación media postoperatoria del KSS tuvo un aumento de 40 puntos (35 [DE±15] vs. 75 [DE±15] [p<0,001]). La media de EVA postoperatoria disminuyó 5 puntos (8 [DE±2] vs. 3 [DE±2] [p<0,001]). Trece pacientes informaron estar muy satisfechos, 13 estaban satisfechos y solo 5 estaban poco satisfechos. Siete pacientes sufrieron complicaciones quirúrgicas y 4 tuvieron inestabilidad rotuliana recurrente. Con una media de 68,2 meses de seguimiento, la tasa de supervivencia global fue del 93,5%. Al considerar el rescate rotuliano secundario como punto final, la tasa de supervivencia fue del 80,6%. Conclusiones: En este estudio, la ATR se asoció con muy buenos resultados funcionales en pacientes con EP. A una media de 68,2 meses de seguimiento, la ATR tuvo una buena supervivencia a corto plazo, siendo la inestabilidad rotuliana recurrente la complicación más frecuente. Aunque estos hallazgos confirman la efectividad de la ATR en esta población, se necesita una evaluación clínica exhaustiva y un enfoque multidisciplinario para disminuir la probabilidad de complicaciones.(AU)

Introduction: Thanks to improvements in the medical treatment of Parkinson's disease (PD), the life expectancy of these patients has increased, but the overall outcome after total knee arthroplasty (TKA) is controversial. We aim to analyse a series of patients with PD, evaluating their clinical status, functional results, complications and survival rates after TKA. Methods: We retrospectively studied 31 patients with PD operated between 2014-2020. The mean age was 71 years (SD±5.8). There were 16 female patients. The mean follow-up was 68.2 months (SD±36). We used the Knee Scoring System (KSS) and the Visual Analog Scale (VAS) for the functional evaluation. The Modified Hoehn and Yahr Scale was used to assess the severity of PD. All complications were recorded, and survival curves were performed. Results: The mean postoperative KSS evaluation had an increase of 40 points [35 (SD±15) vs 75 (SD±15) (P<.001)]. The mean postoperative VAS decreased 5 points [8 (SD±2) vs 3 (SD±2) (P<.001)]. Thirteen patients reported being very satisfied, 13 were satisfied, and only 5 were poorly satisfied. Seven patients suffered surgical complications, and 4 patients had recurrent patellar instability. At a mean 68.2 months follow-up, the overall survival rate was 93.5%. When considering the secondary patellar resurfacing as the endpoint, the survival rate was 80.6%. Conclusions: In this study, TKA was associated with excellent functional outcomes in patients with PD. At a mean 68.2 months follow-up, TKA had excellent survivorship in the short term, with recurrent patellar instability as the most common complication. Even though these findings confirm the effectiveness of TKA in this population, a thorough clinical evaluation and multidisciplinary approach are needed to decrease the likelihood of complications.(AU)

[Translated article] Total knee arthroplasty is effective in patients with Parkinson's disease. Functional assessment and analysis of complications.

INTRODUCTION: Thanks to improvements in the medical treatment of Parkinson's disease (PD), the life expectancy of these patients has increased, but the overall outcome after total knee arthroplasty (TKA) is controversial. We aim to analyse a series of patients with PD, evaluating their clinical status, functional results, complications and survival rates after TKA. METHODS: We retrospectively studied 31 patients with PD operated between 2014 and 2020. The mean age was 71 years (SD±5.8). There were 16 female patients. The mean follow-up was 68.2 months (SD±36). We used the knee scoring system (KSS) and the visual analogue scale (VAS) for the functional evaluation. The modified Hoehn and Yahr scale was used to assess the severity of PD. All complications were recorded, and survival curves were performed. RESULTS: The mean postoperative KSS evaluation had an increase of 40 points [35 (SD±15) vs 75 (SD±15) (p<.001)]. The mean postoperative VAS decreased 5 points [8 (SD±2) vs 3 (SD±2) (p<.001)]. Thirteen patients reported being very satisfied, 13 were satisfied, and only 5 were poorly satisfied. Seven patients suffered surgical complications, and 4 patients had recurrent patellar instability. At a mean 68.2 months follow-up, the overall survival rate was 93.5%. When considering the secondary patellar resurfacing as the endpoint, the survival rate was 80.6%. CONCLUSIONS: In this study, TKA was associated with excellent functional outcomes in patients with PD. At a mean 68.2 months follow-up, TKA had excellent survivorship in the short term, with recurrent patellar instability as the most common complication. Even though these findings confirm the effectiveness of TKA in this population, a thorough clinical evaluation and multidisciplinary approach are needed to decrease the likelihood of complications.

Total knee arthroplasty is effective in patients with Parkinson's disease. Functional assessment and analysis of complications. / La artroplastia total de rodilla en pacientes con enfermedad de Parkinson es efectiva. Evaluación funcional y análisis de complicaciones.

INTRODUCTION: Thanks to improvements in the medical treatment of Parkinson's disease (PD), the life expectancy of these patients has increased, but the overall outcome after total knee arthroplasty (TKA) is controversial. We aim to analyse a series of patients with PD, evaluating their clinical status, functional results, complications and survival rates after TKA. METHODS: We retrospectively studied 31 patients with PD operated between 2014-2020. The mean age was 71 years (SD±5.8). There were 16 female patients. The mean follow-up was 68.2 months (SD±36). We used the Knee Scoring System (KSS) and the Visual Analog Scale (VAS) for the functional evaluation. The Modified Hoehn and Yahr Scale was used to assess the severity of PD. All complications were recorded, and survival curves were performed. RESULTS: The mean postoperative KSS evaluation had an increase of 40 points [35 (SD±15) vs 75 (SD±15) (P<.001)]. The mean postoperative VAS decreased 5 points [8 (SD±2) vs 3 (SD±2) (P<.001)]. Thirteen patients reported being very satisfied, 13 were satisfied, and only 5 were poorly satisfied. Seven patients suffered surgical complications, and 4 patients had recurrent patellar instability. At a mean 68.2 months follow-up, the overall survival rate was 93.5%. When considering the secondary patellar resurfacing as the endpoint, the survival rate was 80.6%. CONCLUSIONS: In this study, TKA was associated with excellent functional outcomes in patients with PD. At a mean 68.2 months follow-up, TKA had excellent survivorship in the short term, with recurrent patellar instability as the most common complication. Even though these findings confirm the effectiveness of TKA in this population, a thorough clinical evaluation and multidisciplinary approach are needed to decrease the likelihood of complications.

Optical spectroscopy study of damage induced in 4H-SiC by swift heavy ion irradiation.

Single crystals of 4H-SiC were irradiated with swift heavy ions (332 MeV Ti, 106 MeV Pb and 2.7 GeV U) in the electronic energy loss regime. The resulting damage was investigated with UV-visible optical absorption spectroscopy and micro-Raman spectroscopy. The evolution of the Raman data with fluence shows an accumulation of isolated point defects without amorphization of the material and a partial recrystallization of the structure, but only at the lowest fluence. Furthermore, the longitudinal optical phonon-plasmon coupling mode disappears upon irradiation, suggesting a strong perturbation of the electronic structure. This evolution is consistent with the optical bandgap decrease and the Urbach edge broadening that was also previously observed for the irradiation with 4 MeV Au ions.

The use of femoral struts and impacted cancellous bone allograft in patients with severe femoral bone loss who undergo revision total hip replacement: a three- to nine-year follow-up.

We determined the midterm survival, incidence of peri-prosthetic fracture and the enhancement of the width of the femur when combining struts and impacted bone allografts in 24 patients (25 hips) with severe femoral bone loss who underwent revision hip surgery. The pre-operative diagnosis was aseptic loosening in 16 hips, second-stage reconstruction in seven, peri-prosthetic fracture in one and stem fracture in one hip. A total of 14 hips presented with an Endoklinik grade 4 defect and 11 hips a grade 3 defect. The mean pre-operative Merle D'Aubigné and Postel score was 5.5 points (1 to 8). The survivorship was 96% (95% confidence interval 72 to 98) at a mean of 54.5 months (36 to 109). The mean functional score was 17.3 points (16 to 18). One patient in which the strut did not completely bypass the femoral defect was further revised using a long cemented stem due to peri-prosthetic fracture at six months post-operatively. The mean subsidence of the stem was 1.6 mm (1 to 3). There was no evidence of osteolysis, resorption or radiolucencies during follow-up in any hip. Femoral width was enhanced by a mean of 41% (19% to 82%). A total of 24 hips had partial or complete bridging of the strut allografts. This combined biological method was associated with a favourable survivorship, a low incidence of peri-prosthetic fracture and enhancement of the width of the femur in revision total hip replacement in patients with severe proximal femoral bone loss.

Paramagnetic defects induced by electron irradiation in barium hollandite ceramics for caesium storage.

We have studied by electron paramagnetic resonance the mechanism of defect production by electron irradiation in barium hollandite, a material used for immobilization of radioactive caesium. The irradiation conditions were the closest possible to those occurring in Cs storage waste forms. Three paramagnetic defects were observed, independently of the irradiation conditions. A hole centre (H centre) is attributed to a superoxide ion O(2)(-) originating from hole trapping by interstitial oxygen produced by electron irradiation. An electron centre (E(1) centre) is attributed to a Ti(3+) ion adjacent to the resulting oxygen vacancy. Another electron centre (E(2) centre) is attributed to a Ti(3+) ion in a cation site adjacent to an extra Ba(2+) ion in a neighbouring tunnel, originating from barium displacement by elastic collisions. Comparison of the effects of external irradiations by electrons with the ß-decay of Cs in storage waste forms is discussed. It is concluded that the latter would be dominated by E(1) and H centres rather than E(2) centres.

Study of damage in ion-irradiated α-SiC by optical spectroscopy.

UV-visible absorption and Raman scattering spectroscopy were used to investigate the effects of 4 MeV Xe-ion and 4 MeV Au-ion irradiations on α-SiC single crystals. The evolution of transmission spectra upon irradiation evidences an increase of the optical absorption. The optical band-gap energy decreases versus fluence, which is linked to band-gap closure attributed to the creation of localized states into the forbidden energy band. A strong effect of the irradiation temperature is observed as a result of dynamic annealing enhanced by the temperature increase. The Urbach energy increases versus fluence due to disorder accumulation in the damaged layer. Comparison of Urbach energy and disorder parameters extracted from Raman spectra shows that the Urbach energy is sensitive to the disorder induced by the accumulation of point defects.

Improvement of hearing after microsurgical removal of acoustic neurinoma.

A case of a 3-cm acoustic neurinoma totally excised with preservation of the facial and cochlear nerves is reported. Hearing was not impaired by the operation, but dramatically improved within 2 months. The literature on operations of acoustic tumors with preservation of hearing is reviewed. In patients with some hearing ability, the operation should be conservative, whatever the size of the neurinoma, because there is a fair chance of success.