T. Belsan

Charles University in Prague, Praha, Praha, Czech Republic

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Publications (25)51.3 Total impact

  • Svatopluk Ostry · Tomas Belsan · Vladimir Benes · David Netuka ·
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    ABSTRACT: Introduction Intraoperative subcortical mapping of the corticospinal tract (CST) using the threshold technique (sc-MEPs) is considered to be helpful during tumour resection adjacent to the CST. Diffusion tensor tractography (DTT) of the CST is feasible. Intraoperative DTT and sc-MEP correlation is thought to be more precise because of brainshift elimination. The goal of the study was to evaluate intraoperative DTT 3.0 T reliability compared with CST mapping in a nonselected series. Methods 25 patients were enrolled consecutively and prospectively between June 2010 and June 2012. Inclusion criteria: solitary supratentorial intracerebral lesion compressing or infiltrating the CST according to preoperative MRI. Subcortical CST mapping was performed by monopolar (cathodal) stimulation (500 Hz, 400Î1/4s, 5 pulses) with a navigated probe. CST DTT was performedon both preoperative and intraoperative 3.0 T MRI. sc-MEP threshold current and probe-CST distance were recorded at 155 points before iMRI (intraoperative MRI) (preoperative scans) and at 103 points after iMRI (intraoperative scans). Current-distance correlations were performed both for pre-iMRI and for post-iMRI data separately. Results The correlation coefficient between pre-iMRI data was R = 0.470 (p << 0.001), post-iMRI data was R = 0.338 (p << 0.001). MRI radical resection was achieved in 17 (68%), subtotal in 5 (24%) and partial in 3 (12%). Postoperative paresis developed in 8 (32%), but was permanent in only one case (4%). The lowest sc-MEP threshold was ⩽⩽ 5.0 mA in 10 (40%); 5–10.0 mA in 9 (36%); >> 10.0 mA in 6 patients (24%). Intraoperative DTT became unreliable because of severe image distortion in 9 (36%). Conclusion The linear current-distance correlation was found both in pre-iMRI and in post-iMRI data. Correlation of post-iMRI data was weaker. Neurophysiological subcortical mapping was more reliable intraoperatively than DTT. Combining these two methods can help increase the safety of tumour resection close to the CST only in selected cases. Supported by IGAMZCR12253-5.
    Clinical Neurophysiology; 05/2014
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    L. Haakova · L. Krofta · T. Belsan · F. Charvat ·

    Ultrasound in Obstetrics and Gynecology 09/2012; 40(S1). DOI:10.1002/uog.12001 · 3.85 Impact Factor
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    ABSTRACT: To compare outcomes of two different types of occlusive therapy of uterine fibroids. Women with fibroid(s) unsuitable for laparoscopic myomectomy (LM) were treated with uterine artery embolization (UAE) or laparoscopic uterine artery occlusion (LUAO). Before the procedure, patients treated with UAE (n = 100) had a dominant fibroid greater in size (68 vs. 48 mm) and a mean age lower (33.1 vs. 34.9 years) than surgically treated patients (n = 100). After 6 months, mean shrinkage of fibroid volume was 53 % after UAE and 39 % after LUAO (p = 0.063); 82 % of women after UAE, but only 23 % after LUAO, had complete myoma infarction (p = 0.001). Women treated with UAE had more complications (31 vs. 11 cases, p = 0.006) and greater incidence of hysteroscopically verified intrauterine necrosis (31 vs. 3 %, p = 0.001). Both groups were comparable in markers of ovarian functions and number of nonelective reinterventions. The groups did not differ in pregnancy (69 % after UAE vs. 67 % after LUAO), delivery (50 vs. 46 %), or abortion (34 vs. 33 %) rates. The mean birth weight of neonates was greater (3270 vs. 2768 g, p = 0.013) and the incidence of intrauterine growth restriction lower (13 vs. 38 %, p = 0.046) in post-UAE patients. Both methods are effective in the treatment of women with future reproductive plans and fibroids not suitable for LM. UAE is more effective in causing complete ischemia of fibroids, but it is associated with greater risk of intrauterine necrosis. Both methods have low rate of serious complications (except for a high abortion rate).
    CardioVascular and Interventional Radiology 04/2012; 35(5):1041-52. DOI:10.1007/s00270-012-0388-y · 2.07 Impact Factor
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    ABSTRACT: A prospective study. The aim of this study was to compare the 3 different methods of interbody fusion of the cervical spine-autograft in stand-alone technique, autograft with anterior plate, and polyetheretherketone cage supported by anterior plate. The clinical and radiological data obtained were analyzed and discussed. Although degenerative cervical spine disease has been treated by an anterior approach for more than 50 years, there is not one generally accepted operative approach. There is a very low-quality evidence of little or no difference in pain relief between each of the techniques. Iliac crest autograft still seems to be the "gold standard" for interbody fusion. Prospective study collecting clinical and radiological data of 81 patients undergoing anterior cervical interbody fusion, in which the interbody fusion of 1 or 2 motion segments from C3 to C7 was done by any of the 3 techniques--stand-alone insertion of autograft (group 1: 28 patients), autograft and anterior plate (group 2: 18 patients), and polyetheretherketone cage filled with beta-tricalcium phosphate and plate (group 3: 29 patients). Patients were followed for 2 years after surgery. Significant interaction of relative height in the segment and time was found (P < 0.001). The values of the relative height of stand-alone autograft dropped below 95% of initial height and the values of the other 2 groups remained above 105%. Significant interaction of time and group was found for Cobb S angles (P < 0.001). Values of group 1 decreased substantially and remained significantly lower than values of other 2 groups. Fusion rate was 100% in all groups. Neck Disability Index group and time interaction was found (P = 0.023). During postoperative follow-up, group 1 scored in all controls higher than the other 2 groups, but differences were not significant. Visual analogue scale showed effect of time (P < 0.001). This was due to a smaller improvement of patients in group 1 during the whole follow-up in comparison with the other 2 groups. Highest proportion of unsatisfied patients was in group 1 compared with the other 2 groups after 2 years (P = 0.034). Significantly worse radiological and clinical results after 2 years of follow-up were achieved using stand-alone autograft technique in comparison with autograft supported by anterior plating similarly as in comparison with cage implant and anterior plating. Using artificial fusion substrate together with plate and cage can offer the same clinical and radiological results such as iliac autograft and plating. Anterior plating seems to be an important factor influencing the postoperative cervical spine alignment and also the clinical outcome.
    Spine 03/2012; 37(19):1645-51. DOI:10.1097/BRS.0b013e31825413fe · 2.30 Impact Factor
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    ABSTRACT: Several atypical hysteroscopy findings have been described in association with uterine artery embolization (UAE). The purpose of this study was to evaluate the types and frequency of these findings in the largest published series of patients. Premenopausal patients after bilateral UAE for symptomatic intramural fibroid underwent subsequent hysteroscopic examination 3-9 months following UAE. The uterine cavity was examined with focus on specific post-embolization changes. Biopsy of endometrium was obtained and evaluated together with a biopsy of abnormal foci if present. UAE was performed in a total of 127 women with an average size of dominant fibroid 63.1 mm in diameter and an average patient age of 35.1 years. Even though the majority of patients were asymptomatic at the time of hysteroscopy (78.0%), the post-embolization hysteroscopic examination was normal in only 51 patients (40.2%). The most frequent abnormalities included tissue necrosis (52 women, 40.9%), intracavitary myoma protrusion (45 women, 35.4%), endometrium 'spots' (22.1%), intrauterine synechiae (10.2%) and 'fistula' between the uterine cavity and intramural fibroid (6.3%). Histopathological examination showed normal, secretory or proliferative endometrium in 83.5% patients. Necrosis and/or hyalinization prevailed in the results of biopsy of abnormal loci (45 cases, 35.4%). Frequency of abnormal hysteroscopic findings several months after UAE for primary intramural myomas is high. Alarmingly high is the percentage of patients with a histopathologically verified necrosis. Performing hysteroscopy in selected patients after UAE is necessary before eventual surgical re-intervention, especially in women with reproductive plans.
    Journal of Obstetrics and Gynaecology Research 03/2012; 38(5):823-31. DOI:10.1111/j.1447-0756.2011.01782.x · 0.93 Impact Factor
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    ABSTRACT: Patients' life expectancy, clinical symptomatology and the extent of carotid stenosis are the most important factors when deciding whether to perform carotid endarterectomy (CEA) in patients with carotid stenosis. Therefore, the accuracy of measuring carotid stenosis is of utmost importance. Patients with internal carotid artery (ICA) stenosis were investigated by digital subtraction angiography (DSA), Doppler ultrasonography (DUS) and magnetic resonance angiography (MRA). Atherosclerotic plaque specimens were transversally cut into smaller segments and histologically processed. The slides were scanned and specimens showing maximal stenosis were determined; the minimal diameter and the diameter of the whole plaque were measured. DSA, DUS and MRA measurements were obtained in 103 patients. A comparison between preoperative and histological findings was performed. In addition, correlation coefficients were computed and tested. Results show a significant correlation for each of the diagnostic procedures. Mean differences in the whole cohort between preoperative measurements and the histological measurements are as follows: angiographic measurement of carotid stenosis underestimated histological measurement by 14.5% and MRA by 0.7%, but DUS overestimated by 6.6%. The results in severe stenosis (> or =70%) are as follows: angiographic measurement underestimated the histological measurements by 2.3%, but MRA overestimated by 12.1% and DUS by 11.3%. The results in moderate stenosis (50-69%): angiographic measurement underestimated the histological measurements by 12.3%, but MRA overestimated by 0.2% and DUS by 7.2%. The results in mild stenosis (30-49%): angiographic measurement underestimated the histological measurements by 24.7% and MRA by 7.6%, but DUS overestimated by 3.3%. Our study confirms that DSA underestimates moderate and mild ICA stenosis. DUS slightly overestimated moderate ICA stenosis and highly overestimated high-grade ICA stenosis. MRA proved to be accurate in detecting moderate ICA stenosis, but slightly underestimated mild stenosis and overestimated high-grade stenosis. The surgeon should be aware of these discrepancies when deciding whether to perform CEA in patients with ICA stenosis.
    Acta Neurochirurgica 07/2010; 152(7):1215-21. DOI:10.1007/s00701-010-0645-2 · 1.77 Impact Factor

  • European journal of pain (London, England) 09/2009; 13. DOI:10.1016/S1090-3801(09)60298-6 · 2.93 Impact Factor
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    ABSTRACT: Our aim was to determine whether the anatomical configuration of the posterior fossa and its substructures might represent a predisposition factor for the occurrence of clinical neurovascular conflict in trigeminal neuralgia (TN). We used MRI volumetry in 18 patients with TN and 15 controls. The volume of the pontomesencephalic cistern, Meckel's cave and the trigeminal nerve on the clinical and non-affected sides was compared. The reliability has been assessed in all measurements. The posterior fossa volume was not different in the clinical and control groups; there was no difference between the affected and non-affected sides when measuring the pontomesencephalic cistern and Meckel's cave volume either. The volume of the clinically affected trigeminal nerve was significantly reduced, but with a higher error of measurement. We did not find any association between the clinical neurovascular conflict (NVC) and the size of the posterior fossa and its substructures. MRI volumetry may show the atrophy of the affected trigeminal nerve in clinical NVC.
    Acta Neurochirurgica 05/2009; 151(6):669-75. DOI:10.1007/s00701-009-0283-8 · 1.77 Impact Factor
  • David Netuka · Vaclav Masopust · Tomas Belsan · Vladimir Beneš ·

    Skull Base Surgery 04/2009; 19(01). DOI:10.1055/s-2009-1222188 · 0.60 Impact Factor
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    ABSTRACT: The purpose of this study was to compare the midterm results of a radiological and surgical approach to uterine fibroids. One hundred twenty-one women with reproductive plans who presented with an intramural fibroid(s) larger than 4 cm were randomly selected for either uterine artery embolization (UAE) or myomectomy. We compared the efficacy and safety of the two procedures and their impact on patient fertility. Fifty-eight embolizations and 63 myomectomies (42 laparoscopic, 21 open) were performed. One hundred eighteen patients have finished at least a 12-month follow-up; the mean follow-up in the entire study population was 24.9 months. Embolized patients underwent a significantly shorter procedure and required a shorter hospital stay and recovery period. They also presented with a lower CRP concentration on the second day after the procedure (p < 0.0001 for all parameters). There were no significant differences between the two groups in the rate of technical success, symptomatic effectiveness, postprocedural follicle stimulating hormone levels, number of reinterventions for fibroid recurrence or regrowth, or complication rates. Forty women after myomectomy and 26 after UAE have tried to conceive, and of these we registered 50 gestations in 45 women. There were more pregnancies (33) and labors (19) and fewer abortions (6) after surgery than after embolization (17 pregnancies, 5 labors, 9 abortions) (p < 0.05). Obstetrical and perinatal results were similar in both groups, possibly due to the low number of labors after UAE to date. We conclude that UAE is less invasive and as symptomatically effective and safe as myomectomy, but myomectomy appears to have superior reproductive outcomes in the first 2 years after treatment.
    CardioVascular and Interventional Radiology 01/2008; 31(1):73-85. DOI:10.1007/s00270-007-9195-2 · 2.07 Impact Factor
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    L. Krofta · J. Feyereisl · M. Otcenasek · L. Haakova · T. Belsan ·

    Ultrasound in Obstetrics and Gynecology 09/2006; 28(4):495 - 495. DOI:10.1002/uog.3328 · 3.85 Impact Factor
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    M. Hrehorcak · L. Rob · T. Belsan · M. J. Halaska · A. Slegrova · R. Vlk ·

    Ultrasound in Obstetrics and Gynecology 09/2005; 26(4):355 - 355. DOI:10.1002/uog.2161 · 3.85 Impact Factor
  • Jaromír Astl · Tomás Belsan · David Veselý ·

    The Journal of otolaryngology 07/2005; 34(3):209-11. DOI:10.2310/7070.2005.03135 · 0.50 Impact Factor
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    ABSTRACT: The aim of our study was to subcategorize Autistic Spectrum Disorders (ASD) using a multidisciplinary approach. Sixty four autistic patients (mean age 9.4+/-5.6 years) were entered into a cluster analysis. The clustering analysis was based on MRI data. The clusters obtained did not differ significantly in the overall severity of autistic symptomatology as measured by the total score on the Childhood Autism Rating Scale (CARS). The clusters could be characterized as showing significant differences: Cluster 1: showed the largest sizes of the genu and splenium of the corpus callosum (CC), the lowest pregnancy order and the lowest frequency of facial dysmorphic features. Cluster 2: showed the largest sizes of the amygdala and hippocampus (HPC), the least abnormal visual response on the CARS, the lowest frequency of epilepsy and the least frequent abnormal psychomotor development during the first year of life. Cluster 3: showed the largest sizes of the caput of the nucleus caudatus (NC), the smallest sizes of the HPC and facial dysmorphic features were always present. Cluster 4: showed the smallest sizes of the genu and splenium of the CC, as well as the amygdala, and caput of the NC, the most abnormal visual response on the CARS, the highest frequency of epilepsy, the highest pregnancy order, abnormal psychomotor development during the first year of life was always present and facial dysmorphic features were always present. This multidisciplinary approach seems to be a promising method for subtyping autism.
    European Child & Adolescent Psychiatry 06/2005; 14(3):138-44. DOI:10.1007/s00787-005-0453-z · 3.34 Impact Factor
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    ABSTRACT: Cyclosporine (CsA) is a widely used immunosuppressant following solid organ transplantation. CsA administration is associated with a number of systemic complications, including neurotoxicity. A 33-year-old man with cystic fibrosis, who underwent bilateral lung transplantation, presented with severe neurotoxic symptoms leading to coma in association with CsA administration combined with high doses of methylprednisolone for treatment of an acute rejection episode. After discontinuation of CsA, a quick resolution of his clinical status was observed, as well as of the pathological findings on magnetic resonance imaging (MRI). CsA was replaced with tacrolimus leading to an uneventful course.
    Transplantation Proceedings 12/2004; 36(9):2837-9. DOI:10.1016/j.transproceed.2004.09.072 · 0.98 Impact Factor
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    I. Spalova · T. Belsan · M. Cihar · M. Kyncl · R. Vlk · E. Kulovaný ·

    Ultrasound in Obstetrics and Gynecology 08/2004; 24(3):369 - 369. DOI:10.1002/uog.1685 · 3.85 Impact Factor
  • E. Zverina · J. Skrivan · J. Betka · J. Kraus · T. Belsan · W.P. Sollmann ·
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    ABSTRACT: From 1997 to 2002, 55 patients with vestibular schwannomas (VS) were managed by radical removal in a one-stage procedure by a retromastoideal posterior fossa approach. Ninety percent of VS were of the 4th grade compressing the brainstem. The described group proves that a high standard of microsurgical technique and intraoperative neurophysiologic monitoring of cranial nerve function is essential. Small VS can be removed without any injury to the facial nerve and with subsequent serviceable hearing. Large VS can be removed with fairly good facial nerve function or with a temporary functional lesion. Less than 10% of operated VS necessitated a facial nerve reconstruction in a cerebellopontine angle (CPA). Cross anastomosis between nerves was never used. No serviceable hearing was maintained after surgery of large VS. Majority of VS in our group (90%) were not suitable for stereoradiosurgery (SRS) because of the size. Five patients operated on for a rapid growth after previous SRS proves that radiotherapy should not be a method of the first choice in VS. Our study supports an opinion that growing VS should be treated in the earliest possible stage. Total removal can be achieved with minimal morbidity and mortality. Auditory brainstem implant (ABI) brings a new chance of maintaining hearing in five patients with neurofibromatosis 2 (NF 2) and bilateral VS.
    International Congress Series 02/2004; 1259(1259):75-79. DOI:10.1016/S0531-5131(03)01546-2
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    European Neuropsychopharmacology 10/2003; 13. DOI:10.1016/S0924-977X(03)92310-8 · 4.37 Impact Factor
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    ABSTRACT: Auditory brainstem implant (ABI) is an electroprosthetic device enabling sound sensations in deaf persons with a bilateral lesion of auditory nerves. Stimulation of auditory nuclei in the floor of the IVth ventricle is realized by an electrode array introduced during surgery in the lateral recess of the IVth ventricle. The main indication group for ABI is represented by patients with neurofibromatosis 2 (NF2) suffering from bilateral vestibular schwannomas. During surgery aimed at tumour removal, auditory nerve function and integrity are almost always destroyed, therefore, an ABI can be introduced as an one stage procedure. Implantees use the device mainly as the aid in lipreading, only very rarely they can comprehend speech without visual cues. Auditory brainstem implant programme has been introduced in the Czech Republic in the year 1999. It was the very first ABI surgery in the Central Europe. Since that time, 5 patients had received the auditory brainstem implant, from which the first four use the device for a longer time. The last operated patient has not been activated yet. It may be said, that ABI represents a benefit to all our patients, in one implanted this benefit is significant, since he can understand speech without lipreading, the other implantees use the device as an aid in lipreading. In one female patient, the device benefit is severely limited by a motoric handicap after partial cerebellar resection during surgery. Nevertheless, she uses the implant on a daily basis, but contact with her is limited and difficult.
    Casopís lékar̆ů c̆eských 02/2003; 142(1):29-33.
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    I. Spalova · T. Belsan · E. Kulovany · M. Kyncl · M. Cihar · R. Vlk ·

    Ultrasound in Obstetrics and Gynecology 01/2003; 22(S1):71 - 71. DOI:10.1002/uog.460 · 3.85 Impact Factor

Publication Stats

236 Citations
51.30 Total Impact Points


  • 2004-2014
    • Charles University in Prague
      • Department of Radiology (2. LF)
      Praha, Praha, Czech Republic
  • 2006-2012
    • Military University Hospital Prague
      Praha, Praha, Czech Republic
  • 2003-2005
    • University Hospital Motol
      Praha, Praha, Czech Republic