The role of lumboperitoneal shunts in the treatment of syringomyelia

2010 ◽  
Vol 13 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Chima O. Oluigbo ◽  
Karen Thacker ◽  
Graham Flint

Object The role of thecoperitoneal shunts in the management of syringomyelia is not well defined. In this study, the authors analyze the outcome of lumboperitoneal shunt procedures carried out to treat syringomyelia in their institution. Methods The authors retrospectively reviewed the medical records of 19 patients who underwent lumboperitoneal shunt procedures for syringomyelia. Results The mean follow-up duration was 25 months (range 3–51 months). Of 16 cases followed up, only 5 patients reported clinical improvement in their preoperative symptoms, but of these, 2 had clear radiological evidence of improvement. Three of 6 patients with syringomyelia due to spinal arachnoiditis improved. Conclusions Lumboperitoneal shunts may lead to useful improvement in the symptoms of a patient with syringomyelia while avoiding the risk of neurological deterioration inherent in myelotomies required for syrinx shunting procedures.

2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 9-20 ◽  
Author(s):  
Hung-Chuan Pan ◽  
Ming-Hsi Sun ◽  
Jason Sheehan ◽  
Meei-Ling Sheu ◽  
Clayton Chi-Chang Chen ◽  
...  

Object In the modern era, stereotactic radiosurgery is an important part of the multidisciplinary and multimodality approach used to treat dural carotid-cavernous fistulas (DCCFs). Based on the ease of performance of techniques to fuse cerebral angiography studies with MR images or CT scans during the radiosurgical procedure, the Gamma Knife and XKnife are 2 of the most popular radiosurgical instruments for patients with DCCF. In this study, the authors compared the efficacy, neurological results, and complications associated with these 2 radiosurgical devices when used for DCCF. Methods Records for 41 patients with DCCF (15 treated using the XKnife and 26 with Gamma Knife surgery [GKS]) were retrieved from a radiosurgical database encompassing the period of September 2000 to August 2008. Among these patients, at least 2 consecutive MR imaging or MR angiography studies obtained after radiosurgery were available for determining radiological outcome of the fistula. All patients received regular follow-up to evaluate the neurological and ophthalmological function at an interval of 1–3 months. The symptomatology, obliteration rate, radiation dose, instrument accuracy, and adverse effects were determined for each group and compared between 2 groups. The data were analyzed using the Student t-test. Results The mean age of the patients was 63 ± 2.6 years, and the mean follow-up period was 63.1 ± 4.4 months (mean ± SD). Thirty-seven patients (90%) achieved an obliteration of the DCCF (93% in the XKnife cohort and 88% for the GKS cohort). In 34 of 40 patients (85%) with chemosis and proptosis of the eyes, these symptoms were resolved after treatment (4 had residual fistula and 2 had arterializations of sclera). All 5 patients with high intraocular pressure demonstrated clinical improvement. Ten (71%) of 14 patients with cranial nerve palsy demonstrated improvement following radiosurgery. Significant discrepancies of treatment modalities existed between the XKnife and GKS groups, such as radiation volume, conformity index, number of isocenters, instrument accuracy, peripheral isodose line, and maximum dosage. The XKnife delivered significantly higher radiation dosage to the lens, optic nerve, optic chiasm, bilateral temporal lobe, and brainstem. Few adverse events occurred, but included 1 patient with optic neuritis (GKS group), 1 intracranial hemorrhage (XKnife group), 1 brainstem edema (XKnife), and 3 temporal lobe radiation edemas (XKnife). Conclusions Radiosurgery affords a substantial chance of radiological and clinical improvement in patients with DCCFs. The Gamma Knife and XKnife demonstrated similar efficacy in the obliteration of DCCFs. However, a slightly higher incidence of complications occurred in the XKnife group.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1076.1-1077
Author(s):  
L. Moroni ◽  
L. Giudice ◽  
G. A. Ramirez ◽  
S. Sartorelli ◽  
A. Cariddi ◽  
...  

Background:Subglottic stenosis (SGS) is defined as airway narrowing below the vocal cords and is a common and potentially life-threatening manifestation of Granulomatosis with Polyangiitis (GPA), with an estimated prevalence of 16-23% (1). Balloon catheter dilation is effective in GPA-related SGS, but relapses are frequent. Little is known about the role of immunosuppression in this setting.Objectives:to analyse the clinical characteristics of a monocentric GPA cohort, describe phenotype differences among patients with and without SGS and investigate the role of surgical and medical treatments on relapse risk and general outcome.Methods:Biopsy-proven patients with SGS were identified by review of medical charts among a cohort of patients with GPA, classified according to the algorithm of the European Medicine Agency (2). The clinical characteristics of patients with SGS were retrospectively collected over a median follow-up time of 15.9 years and compared to those of patients without SGS.Results:Fourteen patients with SGS-GPA were identified, with a female to male ratio of 1:1 and a prevalence of 29.2% among the cohort. The mean ± SD age at GPA onset was 30.8 ± 14.4 years, with a mean time from GPA diagnosis to SGS onset of 4.7 ± 4.2 years. ANCA were positive in 78.6% (54.0% anti-PR3, 18.1% anti-MPO and 27.9% IFI only). The mean Birmingham Vasculitis Activity Score (BVAS) at onset was 10.0 ± 5.6. The main clinical manifestations associated with SGS were crusty rhinitis (100%), sinusitis (78%), pulmonary disease (72.7%), otitis/mastoiditis (50%), glomerulonephritis (42.9%), orbital pseudotumor (28.6%). Six patients (42.9%) received medical treatment only, other six (42.9%) had one to three balloon dilations and two (14.2%) underwent four or more procedures. Eight patients had no SGS relapse (maximum one dilation) and they all received immunosuppression with rituximab (RTX), cyclophosphamide (CYC) or azathioprine (AZA). All patients who received no immunosuppression, methotrexate (MTX) or mycophenolate (MMF) had at least one relapse. Patients treated with MTX or MMF had a mean relapse-free survival of 13.1 months, which was comparable to the one of patients not receiving medical treatment (40.2 months; p=NS) and shorter than the one of patients receiving CYC or RTX (153.2 months; p=0.032). CYC use also inversely correlated with the number of surgical procedures (r=-0.691, p=0.006). Compared to patients without SGS (31 consecutive patients with at least 4 years of follow-up), patients with SGS-GPA had an earlier disease onset (mean age 30.8 vs 50.4 years; p<0.001), but with lower BVAS (mean 10.0 vs 15.3; p=0.013) and showed a higher prevalence of crusty rhinitis (100% vs 67.7%; p=0.019). No difference was observed in damage accrual over time between the two groups.Conclusion:Subglottic stenosis is highly prevalent in patients with GPA and may define a milder disease subset occurring more frequently in younger patients. MTX and MMF might be insufficient to prevent SGS relapses requiring balloon dilation. Aggressive immunosuppression (CYC or RTX) might have a non-redundant role in this setting and reduce the risk of relapses.References:[1]Quinn KA, et al. Subglottic stenosis and endobronchial disease in granulomatosis with polyangiitis. Rheumatology 2019; 58 (12), 2203-2211.[2]Watts R, et al. Development and validation of a consensus methodology for the classification of the ANCA associated vasculitides and polyarteritis nodosa for epidemiological studies. Ann Rheum Dis 2007; 66: 222-7.Disclosure of Interests:Luca Moroni: None declared, Laura Giudice: None declared, Giuseppe Alvise Ramirez: None declared, Silvia Sartorelli: None declared, adriana cariddi: None declared, Angelo Carretta: None declared, Enrica Bozzolo: None declared, Lorenzo Dagna Grant/research support from: The Unit of Immunology, Rheumatology, Allergy and Rare Diseases (UnIRAR) received unresctricted research/educational grants from Abbvie, Bristol-Myers Squibb, Celgene, Janssen, Merk Sharp & Dohme, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, Sanofi-Genzyme, and SOBI., Consultant of: Prof Lorenzo Dagna received consultation honoraria from Abbvie, Amgen, Biogen, Bristol-Myers Squibb, Celltrion, Novartis, Pfizer, Roche, Sanofi-Genzyme, and SOBI.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 497.2-497
Author(s):  
J. Arroyo Palomo ◽  
M. Arce Benavente ◽  
C. Pijoan Moratalla ◽  
B. A. Blanco Cáceres ◽  
A. Rodriguez

Background:Musculoeskeletal ultrasound (MSUS) is frequently used in several rheumatology units to detect subclinical inflammation in patients with joint symptoms suspected for progression to inflammatory arthritis (IA). Synovitis grade I (EULAR-OMERACT combined score) is known to be a casual finding in healthy individuals, but studies headed to unravel its possible role on rheumatic diseases are sparse.Objectives:To investigate the correlation between synovitis grade I, and the diagnosis of IA made after a year follow-up period since MSUS findings, in patients of an MSUS-specialized unit of a Rheumatology Department.Methods:We conducted a descriptive, retrospective and unicentric study. 30 patients were selected from the MSUS-specialized unit of our Rheumatology Department from July-18 to January-19. Patients presenting synovitis grade 0 (exclusively), 2 and/or 3 on combined score were excluded. Data collection at baseline included age, sex, immunological profile and previous physical examination to the MSUS findings, as well as the diagnosis made by the rheumatologist in 1-year visit follow-up: dividing the patient sample into two groups: those who were diagnosed with IA and those not. Non-parametric statistical tests for comparing means were used.Results:The mean age was 51,6 years and 70% were females. 6 (20%) patients were diagnosed with inflammatory arthritis after a year follow-up: 2 (4,8%) psoriatic arthritis, 1 (3,3%) undifferentiated arthritis, 1 (3,3%) rheumatoid arthritis, 1 (3,3%) Sjögren’s syndrome. Non-inflammatory arthropathies were also found 24 (80%), of which, 12 (40%) were non-specific arthralgias and 8 (19%) osteoarthritis.In the group of patients who did not developed an IA the mean C-reactive protein (CPR) value was 3,12 mg/L and erythrocyte sedimentation rate (ESR) was 8,2 mm; all of them were rheumatoid factor (RF) positive and ACPA-negative except one patient. 5 (31,3%) patients presented low antinuclear antibodies (ANAs) levels. In those who HLA B-27 and Cw6 were tested (4,25%); both were negative except for one that was HLA B-27 positive. The median number of swollen and painful joint count was 0, and the mean of joints with MSUS involvement was 3,5; the mean involved metacarpophalangeal (MCP) joints was 1,83; proximal interphalangeal (PIP) joints was 1,48 and distal interphalangeal (DIP) joints 0,21.Among the group of patients that developed an IA the mean of CPR and ESR was 9,27 mg/L and 14,17 mm respectively; 2 (33%) patients were RF- positive, and 1 ACPA-positive. ANAs were positive in 3 cases (50%). The median of swollen joint count was 2 and for painful joint count was 0, the median of joints with MSUS involvement was 4,5. The mean of MSUS involvement was for MCP, PIP and DIP joints: 1,67, 2 and 0. Comparing the means of CPR values in the two groups with Student’s t-test we obtained a statistically significant difference (p=0,023). No other significant differences were found.Conclusion:Despite the limitations and possible statistical bias, the presence of MSUS-defined synovitis grade I and elevated CRP levels could be related to further diagnoses of inflammatory arthropathy. Besides, the absence of synovitis in DIP joints might have a diagnostic role. Normal physical exploration and normal levels of CRP might suggest low MSUS value. However, further research is needed to clarify the role of MSUS-defined synovitis grade I.References:[1]D’Agostino MA et al. Scoring ultrasound synovitis in rheumatoid arthritis: a EULAR-OMERACT ultrasound taskforce-Part 1: definition and development of a standardized, consensus-based scoring system. RMD Open. 2017;3(1):e000428.[2]Van den Berg R et al. What is the value of musculoskeletal ultrasound in patients presenting with arthralgia to predict inflammatory arthritis development? A systematic literature review. Arthritis Research & Therapy (2018) 20:228.Disclosure of Interests:None declared


2021 ◽  
pp. 112067212110206
Author(s):  
Pablo Felipe Rodrigues ◽  
Bernardo Kaplan Moscovici ◽  
Guilherme Ferrara ◽  
Luciano Lamazales ◽  
Marcela Mara Silva Freitas ◽  
...  

Objective: Evaluation of central corneal densitometry changes following Ferrara corneal ring segment implantation in patients with keratoconus, especially the correlation between corneal densitometry and keratometry. Methods: Retrospective, non-comparative, interventional study based on the review of medical records of patients diagnosed with keratoconus who underwent Ferrara corneal ring segment implantation. Pre and post-operative corneal densitometry measurements obtained with Pentacam HR (Oculus, Wetzlar, Germany) were analyzed. The follow-up time was 3 months, and data comparison was made, using specific statistical analysis, with the data of 3 months postoperatively. Results: The study sample consisted of 43 eyes of 36 patients. The mean corrected visual acuity improved from 0.82 LogMAR preoperatively (SD ± 0.33) to 0.19 LogMAR (SD ± 0.13) postoperatively. The mean spherical equivalent varied from −4.63 (SD ± 3.94) preoperatively to −2.16 (SD ± 2.63) postoperatively. Asphericity varied from −0.69 (SD ± 0.32) preoperatively to −0.27 (SD ± 0.31) postoperatively. The mean maximum K was 54.01D (SD ± 3.38) preoperatively and 51.50D (SD ± 2.90) postoperatively. The mean anterior densitometric value was 18.26 (SD ± 2.03) preoperatively and 17.66 (SD ± 1.84) postoperatively. Conclusion: Corneal densitometry is an interesting technology that should be studied in keratoconus patients. Our results suggest that the corneal densitometry in the cornea’s anterior layer reduces after ICRS implantation and correlates with corneal keratometry. Further studies should be performed to increase the knowledge in this field.


2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Ali Demircan ◽  
Zeynep Alkin ◽  
Ceren Yesilkaya ◽  
Gokhan Demir ◽  
Burcu Kemer

Purpose. To compare the visual and anatomic outcomes in patients with persistent diabetic macular edema (DME) who switched from ranibizumab to aflibercept with those who continued with previous ranibizumab therapy. Methods. In this retrospective comparative study, medical records of consecutive patients with center-involved DME ≥ 350 μm who had at least three recent consecutive monthly ranibizumab injections followed by as-needed therapy with either aflibercept or ranibizumab were reviewed. Data were collected at presentation (preinjection), at the intermediary visit, and at the last visit (at the end of the follow-up period). Results. Forty-three eyes of 43 patients were divided into two groups: the switch group (n=20) and the ranibizumab group (n=23). Though no significant improvement was found in the mean BCVA from the intermediary visit to the last visit, there was a difference in the mean CMT in the switch group and the ranibizumab group (p<0.001 and p=0.03, resp.). The mean CMT decreased after the intermediary visit by 188.6 ± 120.5 μm in the switch group and by 60.3 ± 117.1 μm in the ranibizumab group (p=0.003). Conclusions. Both aflibercept and ranibizumab decreased CMT in patients with persistent DME who showed a poor response to ranibizumab injections. However, switching to aflibercept provided only morphologic improvement.


2007 ◽  
Vol 107 (2) ◽  
pp. 290-295 ◽  
Author(s):  
Mehmet Tokmak ◽  
A. Celal Iplikcioglu ◽  
Sirzat Bek ◽  
Cem Atilla Gökduman ◽  
Mustafa Erdal

Object Chronic subdural hematomas (SDHs) are a local inflammatory process that causes the formation of a granulation tissue often referred to as the external or outer membrane. This membrane has abnormally permeable macrocapillaries. Therefore, exudation from the macrocapillaries in the outer membrane of chronic SDH may play an important role in the enlargement of chronic SDH. In this study the authors investigated the role of exudation in chronic SDH. Methods The authors examined 24 patients (16 men and eight women; age range 38–86 years [mean age 61.4 years]) with 27 chronic SDHs. The clinical status of the patients was evaluated according to the classification described by Markwalder. The diagnosis was established on computed tomography (CT) scans in all cases. The authors also used the Nomura Classification for judging the lesion's appearance on CT scans. Immediately after the diagnosis, all patients were administered 20 mCi (740 mBq) technetium-99m human serum albumin. Four hours later, blood and SDH samples were taken and radioactivity levels were measured in each. The ratio of activity of the samples taken from chronic SDH to the radioactivity of blood was determined as a percentage and defined as the exudation rate. On the follow-up CT scan obtained on postoperative Day 20, subdural collections thicker than 5 mm were determined to be a reaccumulation. Results The correlations between the exudation rate and age of the patients, clinical grades, CT appearances, and amount of reaccumulation were investigated. In this series the average exudation rate was 13.24% (range 2.05–28.88%). The mean exudation rates according to the clinical grades assigned to patients were as follows: Grade 0, 8.67 ± 5.64% (three patients); Grade 1, 5.07 ± 1.43% (eight patients); Grade 2, 17.87 ± 3.73% (seven patients); and Grade 3, 19.65 ± 7.67% (six patients). Exudation rates in patients with Grades 2 and 3 were significantly higher than those in Grades 0 and 1 (p < 0.05). The mean exudation rates according to the lesion's appearance on CT scans were found as follows: hypodense appearance, 6.55 ± 4.52% (eight patients); isodense appearance, 11.07 ± 6.32% (five patients); hyperdense appearance, 19.47 ± 13.61% (three patients); and mixed-density appearance, 17.40 ± 5.80% (nine patients). The differences among the groups were significant (p < 0.05). The average exudation rate was statistically higher in the patients with reaccumulation (16.30 ± 8.16%) than that in the patients without reaccumulation (9.96 ± 6.84%) (p < 0.05). Conclusions The exudation rate in chronic SDH is correlated with a higher clinical grade (Markwalder Grade 2 or 3), mixed-density CT appearance, and reaccumulation. Therefore, exudation from macrocapillaries in the outer membrane of chronic SDH probably plays an important role in the pathophysiology and the growth of chronic SDH.


2016 ◽  
Vol 32 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Pamela S Kim ◽  
Muath Bishawi ◽  
David Draughn ◽  
Marab Boter ◽  
Charles Gould ◽  
...  

Background Several studies have shown comparable early efficacy of mechanochemical ablation to endothermal techniques. The goal of this report was to show if early efficacy is maintained at 24 months. Methods This was a two-year analysis on the efficacy of mechanochemical ablation in patients with symptomatic C2 or more advanced chronic venous disease. Patients with reflux in the great saphenous vein involving the sapheno-femoral junction and no previous venous interventions were included. Demographic information, clinical, and procedural data were collected. The occlusion rate of treated veins was assessed with duplex ultrasound. Patient clinical improvement was assessed by Clinical-Etiology-Anatomy-Pathophysiology (CEAP) class and venous clinical severity score. Results Of the initial 126 patients, there were 65 patients with 24 month follow-up. Of these 65 patients, 70% were female, with a mean age of 70 ± 14 years and an average body mass index (BMI) of BMI of 30.5 ± 6. The mean great saphenous vein diameter in the upper thigh was 7.6 mm and the mean treatment length was 39 cm. Adjunctive treatment of the varicosities was performed in 14% of patients during the procedure. Closure rates were 100% at one week, 98% at three months, 95% at 12 months, and 92% at 24 months. There was one patient with complete and four with partial recanalization ranging from 7 to 12 cm (mean length 9 cm). There was significant improvement in CEAP and venous clinical severity score (P < .001) for all time intervals. Conclusion Early high occlusion rate with mechanochemical ablation is associated with significant clinical improvement which is maintained at 24 months, making it a very good option for the treatment of great saphenous vein incompetence.


PEDIATRICS ◽  
1996 ◽  
Vol 98 (6) ◽  
pp. 1119-1121
Author(s):  
Joseph Maytal ◽  
Gerald Novak ◽  
Catherine Ascher ◽  
Robert Bienkowski

Objectives. To determine the association between subtherapeutic antiepileptic drug (AED) levels or AED withdrawal and status epilepticus (SE) in children with epilepsy. Methods. We studied the AED levels at the time of SE in 51 consecutive children with epilepsy. Information about prior AED levels, possible etiology of seizures, and acute precipitants was extracted from medical records. Results. The mean age at the time of SE was 5.7 years (range, 3 months through 18 years). Forty-three patients had history of remote insult, five had history of progressive encephalopathy, and three patients were classified as idiopathic. At the time of SE all AED levels were therapeutic in 34 (66%) patients and at least one level was therapeutic in 42 (82%) patients. All levels were subtherapeutic in 9 (18%) patients. Four patients had their AED reduced or discontinued less than 1 week before SE. Twelve patients with therapeutic AED levels on their most recent clinic visit had at least one subtherapeutic level at the time of SE. Eight (16%) patients were febrile and one was hyponatremic. Of the 51 patients, 31 (61%) had no obvious explanation for the development of SE, as all known AEDs were therapeutic and there were no known acute insults. Conclusions. Neurologically abnormal children with preexisting epilepsy are at high risk for development of SE despite having therapeutic AED levels at that time. Acute precipitants of SE, such as fever or AED withdrawal, may play a role in inducing SE only in a minority of patients.


2016 ◽  
Vol 88 (3) ◽  
pp. 228 ◽  
Author(s):  
Faruk Ozgor ◽  
Abdulmuttalip Simsek ◽  
Ozgu Aydogdu ◽  
Onur Kucuktopcu ◽  
Omer Sarilar ◽  
...  

Objectives: To evaluate the possible role of an hemostatic matrix on hemostasis, perioperative outcomes and complications in patients who underwent laparoscopic partial nephrectomy (LPN). Materials and methods: Patients charts were analyzed retrospectively and their demographic characteristics, operative parameters and follow-up results were recorded. Patients were divided into two groups, according to those who used an hemostatic matrix as Group 1 (n = 41) and those who did not used as Group 2 (n = 44). Demographic characteristics of patients, tumor features, operation time, clamping of the renal vessels, ischemia time, suturing of the collecting system, perioperative hemorrhage and complications were evaluated. Histopathological results, surgical margin status, creatinine level and recurrence at the 3rd month of follow up were analyzed. Statistical analyses were performed with SPSS 17.0 and significance was set at p value of &lt; 0.05. Results: The mean RENAL nephrometry score was 5.9 ± 2.0 and the mean tumor size was 35 ± 12 mm. All patients had a single tumor and 44 of them had a tumor in the right kidney. The renal artery was clamped in 79 cases and the mean ischemia time was 20.1 ± 7 minutes. The mean tumor size and the mean RENAL nephrometry score was statistically higher in Group 1 (p: 0.016 and p &lt; 0.001, respectively). Pelvicaliceal repair was more common in Group 1 due to deeper extension of tumors in this group (p: 0.038). In Group 1, less hemorrhage and blood transfusion requirement, with shorter ischemia and operation time was detected. Conclusion: The outcomes of the recent study showed that adjunctive use of an hemostatic matrix improves hemostasis and decreases hemorrhagic complications during LPN. Further prospective studies are required to assess the potential role of an hemostatic matrix in LPN.


2014 ◽  
Vol 18 (1) ◽  
Author(s):  
Junko Nakamura ◽  
Takeharu Yoshikawa ◽  
Eriko Maeda ◽  
Hiroyuki Akai ◽  
Hiroshi Ohtsu ◽  
...  

Background: The accepted threshold for normal endometrial thickness is 5 mm; lesions with endometrial thickness < 5 mm are considered benign, whilst those > 5 mm areconsidered malignant. However, endometrium ≥ 5 mm on transvaginal ultrasonography inpostmenopausal woman is considered as asymptomatic endometrial thickening. However, recent studies suggest that asymptomatic endometrial thickness of even 8 mm – 11 mm in postmenopausal women may be normal.Objectives: The present study investigated the normal endometrial thickness range in 297 asymptomatic postmenopausal women using 3.0-T magnetic resonance imaging (MRI) T2-weighted sagittal images measured retrospectively by a single radiologist.Method: The data were classified according to patient age and postmenopausal duration, and the medical records and follow-up MR images were reviewed to assess the clinical outcome.Results: The mean endometrial thickness was 2.4 ± 0.1 mm (range: 0.1–11.6). The endometriumin 21 of 297 subjects was ≥ 5 mm thick. Follow-up MR images were obtained in 17 of these 21 women, and their endometrial thickness was found to have decreased in all of them. To date,none of the subjects has been diagnosed with endometrial cancer.Conclusion: Although 5 mm is considered the conservative threshold of normal endometrial thickness on MRI of postmenopausal women, this figure should not, to avoid excessive false-positive diagnoses, be assumed as an indication of malignancy.


Sign in / Sign up

Export Citation Format

Share Document