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1.
Br J Neurosurg ; : 1-6, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38197314

RESUMEN

BACKGROUND: A temporo-sphenoidal encephalocoele occurs when temporal lobe herniates through a defect in the greater wing of the sphenoid bone into the sphenoid air sinus. The natural history is not well-understood, though presentation in adulthood with CSF rhinorrhoea and/or meningitis is typical. Lateral pneumatisation of the sphenoid sinus and elevated BMI may be contributory. AIMS: We explored the feasibility of a transorbital approach (TOA) for repair, using a combination of 3D modelling and simulation. We then successfully deployed this technique in vivo. METHODS: CT imaging for three patients who had previously undergone transcranial repair of lateral temporo-sphenoidal encephalocoele was used to generate data allowing 3D printed models of the skull base to be produced. The transorbital approach was simulated by performing a lateral orbitotomy followed by drilling of the sphenoid wing to expose the antero-basal middle fossa. 3D object scanning was used to create virtual models of the skull base post-surgery, from which surgical access was quantified in two ways: the area (mm2) of the middle fossa exposed by the TOA and the vertical attack angle. RESULTS: The mean surface area of the cranial access window achieved by simulated TOA was 325mm2. The mean vertical attack angle was 25°. One patient was subsequently treated successfully via TOA with no recurrence of their CSF leak, no orbital morbidity, excellent cosmesis, but resolving V2 numbness (follow-up 7 months). CONCLUSIONS: We have shown that the transorbital approach provides adequate surgical access. In our single case, surgical repair of a lateral temporo-sphenoidal encephalocoele via TOA was feasible, safe, and effective. This approach may offer some advantages compared with transcranial or endonasal approaches.

2.
Neurosurg Rev ; 47(1): 13, 2023 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-38102512

RESUMEN

The endoscopic endonasal approach is more disruptive to normal anatomy (particularly nasal mucosa) than the transseptal submucosal microscopic approach. This may result in greater postoperative nasal morbidity, in turn reducing quality of life. We aimed to assess the severity and time course of nasal morbidity, and its impact on quality of life, following endoscopic endonasal skull base surgery in this retrospective cohort study. We identified 95 patients who underwent endoscopic endonasal skull base surgery for anterior skull base pathologies. Nasal-specific questions from the Sino-Nasal Outcome Test-22 (SNOT-22) and the Anterior Skull Base inventory (ASB-12) were combined with quality-of-life questions. Patient demographics, diagnosis, and operative data were collected from electronic records. Age of the cohort ranged from 14-83 years. Time elapsed since surgery ranged from 3-85 months. 85/95 (89%) felt that nasal morbidity associated with surgery was acceptable, given the underlying reason for, and outcome of surgery; 10/95 (11%) did not. 71/95 (75%) reported no change or improvement in olfaction 3-months following surgery. 24/95 (25%) reported a deterioration in olfaction which was mild in 7%, moderate in 7%, and severe in 11%. Nasal crusting, nasal obstruction, and headache were moderately problematic symptoms but improved significantly by 3-month follow-up. Nasal discharge, nasal pain, and nasal whistling were mildly problematic and improved significantly by 3-months. 62/95 (65%) patients reported 'no change' in day-to-day activities due to the effects on their nose after surgery. 19/95 (20%) had 'mild inconvenience', 8/95 (8%) 'moderate inconvenience' and 6/95 (6%) 'severe inconvenience'. Endoscopic anterior skull base surgery is associated with nasal morbidity. Whilst 35% of patients appreciate a consequent negative impact on day-to-day life, the overwhelming majority feel that nasal morbidity is acceptable, given the wider surgical goals.


Asunto(s)
Calidad de Vida , Base del Cráneo , Humanos , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Base del Cráneo/cirugía , Estudios Retrospectivos , Resultado del Tratamiento , Endoscopía , Morbilidad
3.
Surgeon ; 21(6): e352-e360, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37468362

RESUMEN

BACKGROUND: Exposure to stress prior to or during surgery can negatively impact performance. Management of stress is an essential non-technical skill required for safe practice. The effects of exposure to emotional visual stressors on surgical performance are poorly understood. This study aims to develop a model to investigate effects of emotive visual stimuli on simulated laparoscopic performance. METHODS AND MATERIALS: A single-centre cohort study. Thirty novice, simulator-naïve medical students were randomly allocated to view either positive, negative, or neutral emotional images (sourced from validated image registry). Participants focused for 5 s on the image before completing a peg-threading laparoscopic task. Time, instrument distance, speed, acceleration, motion smoothness, and ambidexterity were recorded automatically with instrument tracking software. 8 task cycles were completed; 3 control practices followed by 5 with the stimuli, according to group allocation. RESULTS: The final performance metrics of students (time, distance, speed, and motion smoothness) were not significantly different when comparing positive and neutral stimuli groups to those shown negative stimuli. However, changes were seen in the rate of performance improvements (positive: p = 0.711, p = 0.837, p = 0.297, and p = 0.393) (neutral: p = 0.285, p = 0.918, p = 0.835, and p = 0.396). Participation improved performance metrics overall (p=<0.001, p=<0.001, p = 0.088, p = 0.025, p=<0.001). CONCLUSION: Model systems may be valuable for investigating the impact of stress on surgeon performance. The effect of emotive visual stimuli on surgical performance is complex. This model may aid the further exploration of these relationships and ultimately can provide an environment in which surgeons can develop strategies to mitigate the adverse effect of stressors.


Asunto(s)
Laparoscopía , Cirujanos , Humanos , Proyectos Piloto , Estudios de Cohortes , Competencia Clínica , Laparoscopía/educación , Simulación por Computador
4.
Br J Neurosurg ; 35(3): 251-253, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32590913

RESUMEN

Spontaneous intracranial hypotension (SIH) has been classified as a triad of postural headache, low CSF opening pressure (below 60mmH20) and diffuse pachymeningeal gadolinium enhancement on MRI. SIH is due to a non-iatrogenic defect in the dura somewhere along the neuraxis (usually in the spine). The resultant leak depressurizes the system and undermines the buoyancy-providing quality of CSF. In many cases the site of leak is not identified. Epidural blood patch (EBP) is a well-established treatment of SIH but is not always effective. We retrospectively analysed thirty-one cases of SIH who required at least one EBP. They were managed over a fifteen-year period at a single institution. EBP resulted in a significant improvement in headache for 77% of patients. We report in more detail on a particularly challenging outlier where severe SIH resulted in coma. Serial epidural blood patches, burr hole evacuation of chronic subdural haematomata, and infusion of 0.9% NaCl via an intradural spinal catheter were all required to enable long-term recovery.


Asunto(s)
Hipotensión Intracraneal , Parche de Sangre Epidural , Medios de Contraste , Gadolinio , Humanos , Hipotensión Intracraneal/terapia , Imagen por Resonancia Magnética , Estudios Retrospectivos
5.
Acta Neurochir (Wien) ; 162(6): 1281-1286, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32144485

RESUMEN

BACKGROUND: Enhanced recovery after surgery (ERAS) is a constant motivation. There is growing evidence that an endoscopic (rather than microscopic) transsphenoidal approach to pituitary tumours can play a role, facilitating faster recovery and a commensurate reduction in length of stay (LOS). Reducing LOS is beneficial to both patients and healthcare systems. We sought to assess the safety, patient feedback, and resource implications of adopting an enhanced recovery and accelerated discharge policy for elective pituitary surgery. METHODS: We retrospectively assessed two consecutive cohorts of patients undergoing elective surgery for pituitary adenoma in a single UK centre between July 2016 and November 2019. The pre-ERAS cohort included 52 sequential patients operated prior to protocol change. The ERAS cohort included 55 sequential patients operated after a protocol change. Patient demographic data, tumour characteristics, intra- and post-operative CSF leak, the rate and cause of readmission (within 30 days), and the mean and median LOS were recorded. Patient feedback was collected from a subset of patients (n = 23) in the ERAS group. RESULTS: The two cohorts were well-matched with respect to their demographic, pathological, and operative characteristics. The rates of readmission within 30 days of discharge were similar between the two groups (8% pre-ERAS cohort, 9% ERAS cohort, p = 0.75). In the pre-ERAS cohort, the mean LOS was 4.5 days and median LOS was 3 days. This compares with significant reduction in LOS for the ERAS group: mean of 1.7 days and median of 1 day (p < 0.05). Thirty-nine of 55 patients in the ERAS group were discharged on post-operative day 1. Patient feedback was very positive in the ERAS group (mean patient satisfaction score of 9.7/10 using a Likert scale). CONCLUSIONS: An enhanced recovery protocol after elective endoscopic pituitary surgery is safe, reduces length of stay, and is associated with high patient satisfaction.


Asunto(s)
Procedimientos Quirúrgicos Electivos/efectos adversos , Endoscopía/efectos adversos , Procedimientos Neuroquirúrgicos/efectos adversos , Medición de Resultados Informados por el Paciente , Neoplasias Hipofisarias/cirugía , Complicaciones Posoperatorias/epidemiología , Adulto , Anciano , Costos y Análisis de Costo , Procedimientos Quirúrgicos Electivos/economía , Endoscopía/economía , Femenino , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Procedimientos Neuroquirúrgicos/economía , Alta del Paciente , Complicaciones Posoperatorias/economía
6.
Nanotechnology ; 29(31): 315202, 2018 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-29757752

RESUMEN

We fabricated electrochemical metallization cells using a GaLaSO solid electrolyte, an InSnO inactive electrode and active electrodes consisting of various metals (Cu, Ag, Fe, Cu, Mo, Al). Devices with Ag and Cu active metals showed consistent and repeatable resistive switching behaviour, and had a retention of 3 and >43 days, respectively; both had switching speeds of <5 ns. Devices with Cr and Fe active metals displayed incomplete or intermittent resistive switching, and devices with Mo and Al active electrodes displayed no resistive switching ability. Deeper penetration of the active metal into the GaLaSO layer resulted in greater resistive switching ability of the cell. The off-state resistivity was greater for more reactive active metals which may be due to a thicker intermediate layer.

7.
Childs Nerv Syst ; 33(11): 2047-2049, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28664279

RESUMEN

INTRODUCTION: Delayed diffuse cerebellar swelling is a rare life-threatening complication following medulloblastoma resection. PRESENTATION: We present our experience of managing a 4-year-old who developed diffuse cerebellar swelling with upward herniation 41 days after resection of a large cell anaplastic medulloblastoma. CONCLUSION: Emergency chemotherapy alone was sufficient in promoting regression of swelling and recovery from coma. Reports of similar cases are scant. Chemotherapy may be a critical component of treatment.


Asunto(s)
Edema Encefálico/etiología , Neoplasias Cerebelosas/cirugía , Meduloblastoma/cirugía , Complicaciones Posoperatorias/etiología , Neoplasias Cerebelosas/complicaciones , Preescolar , Humanos , Masculino , Meduloblastoma/complicaciones , Procedimientos Neuroquirúrgicos/efectos adversos
8.
Surgeon ; 14(4): 213-8, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27072790

RESUMEN

There is an expanding interface between electronic engineering and neurosurgery. Rapid advances in microelectronics and materials science, driven largely by consumer demand, are inspiring and accelerating development of a new generation of diagnostic, therapeutic, and prosthetic devices for implantation in the nervous system. This paper reviews some of the basic science underpinning their development and outlines some opportunities and challenges for their use in neurosurgery.


Asunto(s)
Encefalopatías/cirugía , Terapia por Estimulación Eléctrica/métodos , Electrónica , Neuroestimuladores Implantables , Neurocirugia/instrumentación , Neoplasias Encefálicas/cirugía , Femenino , Predicción , Humanos , Masculino , Microelectrodos , Neurocirugia/métodos , Neurocirugia/tendencias , Resultado del Tratamiento
9.
Br J Neurosurg ; 30(3): 286-93, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27101792

RESUMEN

Focused ultrasound (FUS) is an incision-less intervention that is a Food and Drug Association (FDA) approved surgical treatment for various pathologies including uterine fibroids and bone metastases. Recent advances in magnetic resonance imaging thermometry and ability to use FUS across the intact calvarium have re-opened interest in the use of FUS in the treatment of neurological diseases. FUS currently has a European CE mark for use in movement disorders. However, it shows potential in the treatment of other neuropathologies including tumours and as a lesional tool in epilepsy. FUS may exert its therapeutic effect through thermal or mechanical fragmentation of intracranial lesions, or by enhancing delivery of pharmaceutical agents across the blood-brain barrier. In this review, we summarise the mechanisms, clinical applications and potential future of FUS for the treatment of neurological disease. We have searched for and described the recently completed and on-going clinical trials investigating FUS for the treatment of neurological disorders. We identified phase one trials investigating utility of FUS in: movement disorders (including essential tremor and Parkinson's disease), chronic pain, obsessive-compulsive disorder and cerebral tumours. Current literature also reports pre-clinical work exploring utility in epilepsy, neurodegenerative conditions (such as Alzheimer's disease) and thrombolysis. Safety and early efficacy data are now emerging, suggesting that transcalvarial FUS is a feasible and safe intervention. Further evidence is required to determine whether FUS is an effective alternative in comparison to current neurosurgical interventions. The cost of requisite hardware is currently a barrier to widespread uptake in UK neurosurgical centres.


Asunto(s)
Barrera Hematoencefálica/patología , Neoplasias/diagnóstico , Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/patología , Ultrasonografía , Sistemas de Liberación de Medicamentos/métodos , Humanos , Neoplasias/patología , Procedimientos Neuroquirúrgicos/métodos
10.
Surg Innov ; 23(1): 70-7, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26178693

RESUMEN

AIM: To assess the potential of the LEAP™ infrared motion tracking device to map laparoscopic instrument movement in a simulated environment. Simulator training is optimized when augmented by objective performance feedback. We explore the potential LEAP has to provide this in a way compatible with affordable take-home simulators. METHOD: LEAP and the previously validated InsTrac visual tracking tool mapped expert and novice performances of a standardized simulated laparoscopic task. Ability to distinguish between the 2 groups (construct validity) and correlation between techniques (concurrent validity) were the primary outcome measures. RESULTS: Forty-three expert and 38 novice performances demonstrated significant differences in LEAP-derived metrics for instrument path distance (P < .001), speed (P = .002), acceleration (P < .001), motion smoothness (P < .001), and distance between the instruments (P = .019). Only instrument path distance demonstrated a correlation between LEAP and InsTrac tracking methods (novices: r = .663, P < .001; experts: r = .536, P < .001). Consistency of LEAP tracking was poor (average % time hands not tracked: 31.9%). CONCLUSION: The LEAP motion device is able to track the movement of hands using instruments in a laparoscopic box simulator. Construct validity is demonstrated by its ability to distinguish novice from expert performances. Only time and instrument path distance demonstrated concurrent validity with an existing tracking method however. A number of limitations to the tracking method used by LEAP have been identified. These need to be addressed before it can be considered an alternative to visual tracking for the delivery of objective performance metrics in take-home laparoscopic simulators.


Asunto(s)
Simulación por Computador , Laparoscopía/educación , Humanos , Reproducibilidad de los Resultados , Análisis y Desempeño de Tareas
11.
Cochrane Database Syst Rev ; (8): CD003434, 2015 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-26250102

RESUMEN

BACKGROUND: Idiopathic intracranial hypertension (IIH) has an estimated incidence of one to three people per 100,000 people per year, and occurs most commonly in obese, young women. IIH is associated with severe morbidity, notably due to a significant threat to sight and severe headache. Several different management options have been proposed. Conservative measures centre on weight loss. Pharmacological therapy includes use of diuretics. Refractory and sight-threatening cases demand surgical intervention, most often in the form of cerebrospinal fluid (CSF) diversion or optic nerve sheath fenestration. Other treatments include venous sinus stenting and bariatric surgery. OBJECTIVES: To assess the effects of any intervention for IIH in any patient group. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015 Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2015), EMBASE (January 1980 to July 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 22 July 2015. SELECTION CRITERIA: We included only randomised controlled trials (RCTs) in which any intervention was compared to placebo, or to another form of treatment, for people with a clinical diagnosis of IIH. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the search results for trials to be included in the review. We resolved any discrepancies by third party decision. MAIN RESULTS: We identified two completed RCTs (enrolling a total of 211 participants and conducted in the UK and US) and two ongoing trials that met the inclusion criteria. Both completed trials compared acetazolamide to placebo, in conjunction with a weight loss intervention in both groups. Attrition bias was a problem in both trials with high loss to follow-up, in one study this loss to follow-up occurred particularly in the acetazolamide arm. One trial was unmasked and we judged it to be at risk of performance and detection bias.In these studies, change in visual acuity was similar in the treatment and control groups as measured by logMAR acuity. In one study people in the acetalomazide group had a similar change in logMAR acuity compared to the placebo group between baseline and 12 months in the right eye (MD 0.04 logMAR, 95% CI -0.08 to 0.16) and left eye (MD 0.03 logMAR, 95% CI -0.09 to 0.15). In the other study people in the acetalomazide group had a similar change in vision over six months compared with people in the placebo group (mean difference in change in letters read was 0.01 (95% CI -1.45 to 1.46). One study reported no cases of visual loss in 21 people treated with acetalomazide compared to 2/20 cases in the placebo group (odds ratio 0.17, 95% CI 0.01, 3.82).The prespecified outcome for this review was reduction in CSF pressure to normal levels which was not reported by the two trials. One trial reported that, in a subsample of 85 participants who agreed to lumbar puncture at 6 months, people in the acetalomazide group on average had a greater reduction in CSF pressure (MD -59.9 mmH(2)O, 95% CI -96.4, -23.4).In one study, people in the acetalozamide group on average experienced a greater reduction in papilloedema as assessed by fundus photographs MD -0.70 (95% CI -1.00 to -0.40) and by clinical grading MD -0.91 (95% CI -1.27 to -0.54) between baseline and six months in the study eye.Headache was recorded as present/absent in one study at 12 months (OR 0.42, 95% CI 0.12,1.41, 41 participants). Both studies reported headache on visual analogue scales (different ones) but results were inconclusive (MD for change in headache score measured on 10-point visual analogue scale at 12 months was 1.0 (-1.80, 3.70, 41 participants) and MD for change in headache score on a 6 point scale measured at 6 months was -0.45 (-3.5,2.6, number of participants unclear).In one study, a similar proportion of people in the acetalomazide group were in remission (however, the trial authors did not state their definition of this term) at 12 months compared to the placebo group. However, the 95% CIs were wide and there is considerable uncertainty as to the effect (OR 1.13 (95% CI 0.32 to 3.90, 41 participants).In one study of 185 participants, people in the acetalomazide group had an increased risk of decreased CO2, diarrhoea, dysgeusia, fatigue, nausea, paresthesia, tinnitus and vomiting compared to people in the placebo group. In general, the estimates of effect were uncertain with wide 95% CIs. Adverse effects were not reported in the other study.One study reported that quality of life was better in acetazolamide-treated patients based on the visual quality of life (VFQ-25) (MD 6.35, 95% CI 2.22 to 10.47) and the physical (MD 3.02, 95% CI 0.34 to 5.70) and mental (MD 3.45, 95% CI 0.35 to 6.55) components of the 36-Item Short Form Health Survey tool at six months. Costs were not reported in either study.We judged the evidence to be low certainty (GRADE) downgrading for imprecision and risk of bias. AUTHORS' CONCLUSIONS: Although the two included RCTs showed modest benefits for acetazolamide for some outcomes, there is insufficient evidence to recommend or reject the efficacy of this intervention, or any other treatments currently available, for treating people with IIH. Further high-quality RCTs are required in order to adequately assess the effect of acetazolamide therapy in people with IIH.


Asunto(s)
Acetazolamida/uso terapéutico , Antihipertensivos/uso terapéutico , Hipertensión Intracraneal/terapia , Adulto , Presión del Líquido Cefalorraquídeo/efectos de los fármacos , Femenino , Cefalea/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Ensayos Clínicos Controlados Aleatorios como Asunto , Agudeza Visual , Pérdida de Peso
12.
Br J Neurosurg ; 29(5): 712-4, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25822093

RESUMEN

We report the use of three-dimensional or 3D printed, patient-specific anatomy as a tool to improve informed patient consent and patient understanding in a case of posterior lumbar fixation. Next, we discuss its utility as an educational tool to enhance imaging interpretation by neurosurgery trainees.


Asunto(s)
Modelos Anatómicos , Neurocirugia/educación , Medicina de Precisión/métodos , Impresión Tridimensional , Fusión Vertebral/métodos , Columna Vertebral/anatomía & histología , Columna Vertebral/cirugía , Femenino , Humanos , Consentimiento Informado , Región Lumbosacra/anatomía & histología , Región Lumbosacra/cirugía , Imagen por Resonancia Magnética , Persona de Mediana Edad , Espondilolistesis/cirugía , Tomografía Computarizada por Rayos X
13.
Br J Neurosurg ; 29(2): 164-8, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24814530

RESUMEN

INTRODUCTION: Society of British Neurological Surgeons (SBNS) meetings are important national events which allow for the presentation of current academic work. The publication rate of presented abstracts is considered a proxy marker of the scientific strength of a conference. We aimed to determine the publication fate of presented abstracts at SBNS meetings over a 5-year period. METHODS: A retrospective review of SBNS conference proceedings between 2001 and 2005 was performed. To ascertain whether an abstract resulted in peer-reviewed publication, a range of databases (PubMed, Google Scholar, Medline and Ovid) were interrogated. Abstracts published in full were subsequently assessed for journal impact factor (IF), time of publication and number of citations received (per Google Scholar). RESULTS: A total of 494 abstracts were presented. Of these, 181 abstracts were subsequently published in full, giving the conference a publication rate of 36.6%. The mean time to publication from presentation was 22 months (range 35 months pre-presentation to 133 months afterwards). The top three journals for publication were the British Journal of Neurosurgery (23.2%), Neurosurgery (7.7%) and Journal of Neurosurgery (7.7%). The IF of journal destinations ranged from no IF to 38.28 (median=1.97). Number of citations ranged from 0 to 963 (median=22). Abstracts with positive results were significantly more likely to be published in full compared to those with negative results (p=0.0001). CONCLUSIONS: SBNS conferences have a respectable publication rate. Those abstracts that are published in full have gone on to gain a considerable number of citations reflecting their scientific relevance. However, studies presented at SBNS are susceptible to positive outcome bias.


Asunto(s)
Bibliometría , Neurocirujanos , Humanos , Revisión de la Investigación por Pares , Estudios Retrospectivos , Sociedades Médicas , Factores de Tiempo
14.
Opt Express ; 22(24): 29292-303, 2014 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-25606863

RESUMEN

We report the lattice site and symmetry of optically active Dy3+ and Tm3+ implanted Si. Local symmetry was determined by fitting crystal field parameters (CFPs), corresponding to various common symmetries, to the ground state splitting determined by photoluminescence measurements. These CFP values were then used to calculate the splitting of every J manifold. We find that both Dy and Tm ions are in a Si substitution site with local tetragonal symmetry. Knowledge of rare-earth ion symmetry is important in maximising the number of optically active centres and for quantum technology applications where local symmetry can be used to control decoherence.


Asunto(s)
Disprosio/química , Fotones , Teoría Cuántica , Silicio/química , Tulio/química , Cristalización , Luminiscencia , Electricidad Estática , Termodinámica
15.
Opt Express ; 21(7): 8101-15, 2013 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-23571900

RESUMEN

Reaction order in Bi-doped oxide glasses depends on the optical basicity of the glass host. Red and NIR photoluminescence (PL) bands result from Bi(2+) and Bin clusters, respectively. Very similar centers are present in Bi- and Pb-doped oxide and chalcogenide glasses. Bi-implanted and Bi melt-doped chalcogenide glasses display new PL bands, indicating that new Bi centers are formed. Bi-related PL bands have been observed in glasses with very similar compositions to those in which carrier-type reversal has been observed, indicating that these phenomena are related to the same Bi centers, which we suggest are interstitial Bi(2+) and Bi clusters.


Asunto(s)
Bismuto/química , Calcógenos/química , Vidrio/química , Plomo/química , Mediciones Luminiscentes/métodos , Modelos Químicos , Simulación por Computador , Ensayo de Materiales
16.
Cureus ; 15(6): e40398, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37456409

RESUMEN

Endocrine disturbances such as diabetes insipidus (DI) and syndrome of inappropriate antidiuretic hormone secretion (SIADH) are recognized complications of craniopharyngioma surgery, which occur due to damage to structures that produce or store antidiuretic hormone (ADH). Intracranial hypotension is a clinical syndrome that presents with headache and typical radiological features and can occur due to a leak of cerebral spinal fluid (CSF) in operations that involve the opening of the arachnoid (e.g., craniopharyngioma surgery). We describe a patient presenting with headache, radiological evidence of intracranial hypotension, and chronic DI after craniopharyngioma surgery. This occurred in the absence of evidence of a CSF leak. The headache and radiological findings resolved after the identification and treatment of DI. Intracranial hypotension may have occurred secondary to dehydration in chronic DI. A 48-year-old woman presented with progressive visual field loss due to cystic recurrence of a craniopharyngioma. She underwent redo (second) extended endoscopic transsphenoidal surgery, having previously undergone an uncomplicated debulking procedure two years prior. Her redo operation was uneventful, and her vision improved postoperatively. A lumbar drain was placed preoperatively to protect the skull base repair and was removed after 48 hours. In the initial postoperative period, she developed a clinical (polyuria) and biochemical picture consistent with DI, subsequently reverting to a SIADH, after which fluid and sodium homeostasis appeared to normalize, and she was discharged. Two months after discharge, she re-presented with new headaches eased by lying flat. Magnetic resonance imaging (MRI) brain showed bilateral convexity subdural effusions and diffuse pachymeningeal enhancement, suggesting intracranial hypotension and raising concern for postoperative CSF leak. MRI spine did not show a CSF fistula at the site of the previous lumbar drain. Transsphenoidal examination under anesthesia showed a well-healed skull base repair and no evidence of CSF leak. She concurrently reported polyuria and polydipsia. A formal water deprivation test confirmed central DI. Treatment with desmopressin improved her headache, and a follow-up MRI brain showed resolution of the previous stigmata of intracranial hypotension. This case report reminds physicians and neurosurgeons that systemic disorders (such as dehydration) can cause intracranial hypotension.

17.
J Neurol Surg B Skull Base ; 84(5): 463-469, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37671293

RESUMEN

Objectives Informed consent is fundamental to good practice. We hypothesized that a personalized three-dimensional (3D)-printed model of skull base pathology would enhance informed consent and reduce patient anxiety. Design Digital images and communication in medicine (DICOM) files were 3D printed. After a standard pre-surgery consent clinic, patients completed part one of a two-part structured questionnaire. They then interacted with their personalized 3D printed model and completed part two. This explored their perceived involvement in decision-making, anxiety, concerns and also their understanding of lesion location and surgical risks. Descriptive statistics were used to report responses and text classification tools were used to analyze free text responses. Setting and Participants In total,14 patients undergoing elective skull base surgery (with pathologies including skull base meningioma, craniopharyngioma, pituitary adenoma, Rathke cleft cyst, and olfactory neuroblastoma) were prospectively identified at a single unit. Results After 3D model exposure, there was a net trend toward reduced patient-reported anxiety and enhanced patient-perceived involvement in treatment. Thirteen of 14 patients (93%) felt better about their operation and 13/14 patients (93%) thought all patients should have access to personalized 3D models. After exposure, there was a net trend toward improved patient-reported understanding of surgical risks, lesion location, and extent of feeling informed. Thirteen of 14 patients (93%) felt the model helped them understand the surgical anatomy better. Analysis of free text responses to the model found mixed sentiment: 47% positive, 35% neutral, and 18% negative. Conclusion In the context of skull base neurosurgery, personalized 3D-printed models of skull base pathology can inform the surgical consent process, impacting the levels of patient understanding and anxiety.

18.
J Laparoendosc Adv Surg Tech A ; 32(2): 189-196, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34860611

RESUMEN

Background: Surgical training emphasizes technical competence. Growing evidence indicates that nontechnical skills are also significant in determining performance. Critically, surgeons should be aware how performance is affected by pressure or distraction. We assessed the impact of novel auditory and visual stressors on performance during a simulated laparoscopic task. We hypothesized that the stressors would worsen performance, and that stress-induced diminution in performance would be inversely related to surgical experience. Methods: Twenty participants (10 surgeons and 10 medical students) completed a peg-threading task using a laparoscopic simulator: three times under control conditions, next with a visual distraction overlay (progressive red saturation of the surgical field, timing personalized to the user's index performance), and then with an auditory distraction overlay (operating theater environment noise). Task completion time and instrument tracking metrics (instrument tip distance traveled and instrument smoothness) were measured. Results: Under control conditions, surgeons completed the task significantly faster, with greater economy of movement, and improved instrument smoothness-compared with students. When exposed to distracting stimuli, the groups behaved differently. Surgeons completed the task more slowly, instrument movements became less smooth (significantly so under audio distraction conditions), but total distance traveled by instruments was unchanged. By contrast, student performance was not impaired and, in some ways, improved. Conclusion: The impact of visual and auditory distraction on surgical performance can be modeled in a laparoscopic simulation environment. The effect of distraction varies according to expertise. This environment may be an effective setting within which to learn to mitigate stress-induced diminution in performance.


Asunto(s)
Laparoscopía , Estudiantes de Medicina , Cirujanos , Competencia Clínica , Simulación por Computador , Humanos , Análisis y Desempeño de Tareas
19.
Br J Neurosurg ; 25(3): 347-51, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21501057

RESUMEN

Our professional and personal lives depend increasingly on access to information via the Internet. As an open access resource, the Internet is on the whole unbridled by censorship and can facilitate the rapid propagation of ideas and discoveries. At the same time, this liberty in sharing information, being unregulated and often free from external validation, can be oppressive; overloading the user and hindering effective decision-making. It can be difficult, if not impossible, to reliably ascertain the provenance of data and opinion. We must, therefore, discern what is useful, relevant, and above all reliable if we are to harness the Internet's potential to improve training, delivery of care, research, and provision of patient information. This article profiles the resources currently available to neurosurgeons, asks how we can sort the informational wheat from the chaff, and explores where future developments might further influence neurosurgical practice.


Asunto(s)
Educación Médica Continua/tendencias , Difusión de la Información/métodos , Internet , Neurocirugia/tendencias , Educación Médica Continua/organización & administración , Humanos , Neurocirugia/educación , Revisión de la Investigación por Pares/normas , Revisión de la Investigación por Pares/tendencias
20.
Br J Neurosurg ; 25(6): 778-9, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21707263

RESUMEN

Confident intra-operative localisation of thoracic spinal pathology remains challenging. Several strategies are routinely employed, including intra-operative fluoroscopy and pre-operative image-guided skin marking. These techniques are limited both by potential inaccuracy and inconvenience. Here we present a novel, efficient and accurate technique for intra-operative localisation of thoracic spinal pathology using pre-operative CT-guided placement of a flexible hook-wire marker.


Asunto(s)
Cuidados Preoperatorios/métodos , Cirugía Asistida por Computador/métodos , Vértebras Torácicas/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Humanos , Desplazamiento del Disco Intervertebral/diagnóstico por imagen , Desplazamiento del Disco Intervertebral/cirugía , Cuidados Intraoperatorios/métodos , Neoplasias de Tejido Nervioso/diagnóstico por imagen , Neoplasias de Tejido Nervioso/cirugía , Neoplasias de la Médula Espinal/cirugía , Vértebras Torácicas/cirugía
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