Nicolas Theumann

University Hospital of Lausanne, Lausanne, Vaud, Switzerland

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Publications (78)187.69 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. MATERIALS AND METHODS: Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs. RESULTS: With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ=+0.1mm, p≤0.040), and noticed more contrast medium therein (p≤0.035). In contrast, the differences in width of the LT (mean Δ=+0.1mm, p≥0.057) and UTFC (mean Δ=0mm, p≥0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p=0.607 and ≥0.157, respectively). Both readers detected more SL (Δ=+1, p=0.157) and LT (Δ=+2, p=0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ=+5, p=0.025). CONCLUSION: The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.
    European journal of radiology 06/2013; · 2.65 Impact Factor
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    ABSTRACT: The objective of our study was to report the MRI findings in dorsal fractures of the triquetrum, with an emphasis on dorsal carpal ligament injuries. A total of 21 patients (16 men, five women; mean age, 41.9 years) with acute or subacute (≤ 6 weeks) dorsal triquetral fractures on radiography and MRI were included in this two-center retrospective study. MRI of the wrist was performed on 3-T units with transverse T1-weighted, coronal or transverse (or both) fat-suppressed T2weighted, transverse gadolinium-enhanced fat-suppressed T1-weighted turbo spin-echo, and 3D gadolinium-enhanced fat-suppressed T1-weighted gradient-recalled echo sequences. Three musculoskeletal radiologists evaluated the ulnar styloid process index (USPI) on radiographs and the following MRI features: fracture pattern (types 1-6), bone fragment size and displacement, bone marrow edema distribution, and dorsal carpal ligament tears. Eight type 1, one type 2, six type 3, five type 4, and one type 5 fractures were identified. These fractures were associated with 14 (66.7%), 17 (81.0%), and 16 (76.2%) tears of the dorsal radiocarpal, ulnotriquetral, and intercarpal ligaments, respectively. There was no correlation between bone marrow edema distribution and dorsal carpal ligament injuries (all p > 0.05). The mean (± SD) bone fragment volume and displacement were 205 ± 157 mm(3) and 1.0 ± 1.1 mm, respectively. The mean USPI was 0.21 ± 0.10. Dorsal fractures of the triquetrum are frequently associated with dorsal carpal ligament injuries. Bone marrow edema distribution is not correlated with these ligament tears.
    American Journal of Roentgenology 03/2013; 200(3):608-17. · 2.90 Impact Factor
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    ABSTRACT: PURPOSE: To assess the value of adding axial traction to direct MR arthrography of the shoulder, in terms of subacromial and glenohumeral joint space widths, and coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material. MATERIALS AND METHODS: Twenty-one patients investigated by direct MR arthrography of the shoulder were prospectively included. Studies were performed with a 3 Tesla (T) unit and included a three-dimensional isotropic fat-suppressed T1-weighted gradient-recalled echo sequence, without and with axial traction (4 kg). Two radiologists independently measured the width of the subacromial, superior, and inferior glenohumeral joint spaces. They subsequently rated the amount of contrast material around the superior labrum-biceps tendon complex and between glenohumeral cartilage surfaces, using a three-point scale: 0 = no, 1 = partial, 2 = full. RESULTS: Under traction, the subacromial (Δ = 2.0 mm, P = 0.0003), superior (Δ = 0.7 mm, P = 0.0001) and inferior (Δ = 1.4 mm, P = 0.0006) glenohumeral joint space widths were all significantly increased, and both readers noted significantly more contrast material around the superior labrum-biceps tendon complex (P = 0.014), and between the superior (P = 0.001) and inferior (P = 0.025) glenohumeral cartilage surfaces. CONCLUSION: Direct MR arthrography of the shoulder under axial traction increases subacromial and glenohumeral joint space widths, and prompts better coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 09/2012; · 2.57 Impact Factor
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    ABSTRACT: To evaluate the influence of shorter- and longer-acting intra-articular anaesthetics on post-arthrographic pain. 154 consecutive patients investigated by MR or CT arthrographies were randomly assigned to one of the following groups: 1--intra-articular contrast injection only; 2--lidocain 1% adjunction; or 3--bupivacain 0.25% adjunction. Pain was assessed before injection, at 15 min, 4 h, 1 day and 1 week after injection by visual analogue scale (VAS). At 15 min, early mean pain score increased by 0.96, 0.24 and 0 in groups 1, 2 and 3, respectively. Differences between groups 1 & 3 and 1 & 2 were statistically significant (p=0.003 and 0.03, respectively), but not between groups 2 & 3 (p=0.54). Delayed mean pain score increase was maximal at 4 h, reaching 1.60, 1.22 and 0.29 in groups 1, 2 and 3, respectively. Differences between groups 1 & 2 and 2 & 3 were statistically significant (p=0.002 and 0.02, respectively), but not between groups 1 & 2 (p=0.46). At 24 h and 1 week, the interaction of local anaesthetics with increase in pain score was no longer significant. Results were independent of age, gender and baseline VAS. Intra-articular anaesthesia may significantly reduce post-arthrographic pain. Bupivacain seems to be more effective than lidocain to reduce both early and delayed pain.
    European journal of radiology 07/2012; 81(9):e957-61. · 2.65 Impact Factor
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    ABSTRACT: Pregnancy-associated osteoporosis usually appears during the first pregnancy and does not affect the followings. We report two cases where non-traumatic fractures have been diagnosed shortly after delivery of second pregnancies. Wide investigations could not find a cause of secondary osteoporosis. In the first case we came to the diagnosis of pregnancy-associated osteoporosis and an intravenous treatment of ibandronate has been prescribed. In the second case the bone mineral density (BMD) being almost normal and the localisation of the fracture being atypical, we concluded to a fracture of non-osteoporotic origin, probably due to mechanical stress during pregnancy. No therapy against osteoporosis has been prescribed.
    Praxis 07/2012; 101(14):923-8.
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    ABSTRACT: Vertebral osteoporotic fracture (VOF) is a major problem of public health. Surgical treatments such as vertebroplasty and kyphoplasty are interesting adjuvant treatments for the management of osteoporosis. A consensus proposed by the principal contributors of this management is important. Regarding the actual data, we propose a vertebroplasty or a kyphoplasty for all patients suffering of an acute VOF. If a previous kyphosis or an important local kyphosis exists, secondary to the acute VOF or others, we propose a kyphoplasty. If the VOF is older and the conservative treatment is inefficient, we propose a vertebroplasty. In all cases, a specific management and treatment of osteoporosis is proposed.
    Revue médicale suisse 06/2012; 8(347):1417-21.
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    Skeletal Radiology 05/2012; · 1.74 Impact Factor
  • Skeletal Radiology 05/2012; · 1.74 Impact Factor
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    François Luthi, Yan Eggel, Nicolas Theumann
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    ABSTRACT: Retinoids are effective and widely prescribed in the treatment of severe acne. However their use can be associated with numerous side effects. Some rare cases of premature epiphyseal closure were reported. We present the case of a sixteen-year-old soccer player referred for progressive anterior pain in both knees, evoking a patellar problem. Careful pharmacological questioning revealed use of isotretinoin for several months. MRI findings showed an irregularity of the growth plate and an important metaphyso-epiphyseal oedema, more noticeable in the left knee. Retinoid-induced premature epiphyseal closure was diagnosed. The treatment was stopped, with a resolution of pain within two months. After recovery a persisting small sequelar thumbprint-like growth plate lesion was observed on the control MRI. Retinoids induce an invasion of the growth plate by osteoclasts and a decrease in proteoglycans synthesis. It seems that the knee is the most affected joint. This complication being rare, a radiological follow-up of the young patients treated by retinoids is not proposed.
    Joint, bone, spine: revue du rhumatisme 12/2011; 79(3):314-6. · 2.25 Impact Factor
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    ABSTRACT: Osteochondritis dissecans (OCD) is a joint disorder that affects the articular cartilage and subchondral bone, most commonly at the knee. OCD of the sacroiliac joint is extremely rare. Management of OCD remains controversial, and surgery is often needed, especially when conservative treatment fails. We present a rare case of OCD involving the left sacroiliac joint successfully treated by percutaneous computed tomography-guided retrograde drilling and debridement.
    CardioVascular and Interventional Radiology 12/2011; 35(4):963-7. · 2.09 Impact Factor
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    ABSTRACT: The glomus tumor is a rare, benign, but painful vascular neoplasm arising from the neuromyoarterial glomus. Primary intraosseous glomus tumor is even rarer, with only about 20 cases reported in the literature so far, 5 of which involved the spine. Surgical resection is currently considered the treatment of choice. We herewith present an uncommon case of primary intraosseous spinal glomus tumor involving the right pedicle of the eleventh thoracic vertebra (T11). To our knowledge, this is the first case of primary intraosseous spinal glomus tumor successfully treated by percutaneous CT-guided radiofrequency ablation (RFA).
    Skeletal Radiology 11/2011; 41(4):467-72. · 1.74 Impact Factor
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    ABSTRACT: Palmer previously proposed a classification system of triangular fibrocartilage complex (TFCC) injuries that proved to be useful in directing clinical management. However, dorsal peripheral tears (variants of class 1C) were not described and have rarely been reported in the literature since. We herewith present a rare case of bucket-handle tear of the TFCC. To our knowledge, this is the first case demonstrating partial separation of both the palmar and dorsal distal radioulnar ligaments (DRULs) from the articular disc. The particular wrist magnetic resonance (MR) arthrographic findings of this unusual complex peripheral TFCC tear (a variant of both class 1B and 1C) were nicely appreciated upon sagittal reformatted images.
    Skeletal Radiology 09/2011; 40(12):1617-21. · 1.74 Impact Factor
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    ABSTRACT: To assess the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography of the wrist with regard to joint space width and amount of contrast material between the opposing cartilage surfaces. Fifteen consecutive patients (12 male, mean age 38.1 years) were included in this Institutional Review Board-approved prospective study. Three-compartment wrist MR arthrographies were performed between October and December 2009 on a 3 T unit using a fat-suppressed T1-weighted isotropic high-resolution volumetric interpolated breathhold examination (VIBE) sequence in the coronal plane, with and without axial traction (3 kg). Two radiologists measured radiocarpal (radioscaphoid, radiolunate) and midcarpal (lunocapitate, hamatolunate) joint space widths, with and without traction, and assessed the amount of contrast material between the opposing cartilage surfaces using a three-point scale: 0 = absence, 1 = partial, 2 = complete. With traction, joint space width increased significantly at the radioscaphoid (Δ = 0.78 mm, P < 0.01), radiolunate (Δ = 0.18 mm, P < 0.01), and lunocapitate (Δ = 0.45 mm, P < 0.01) spaces, and both observers detected significantly more contrast material between the cartilage surfaces. At the hamatolunate space, the differences in joint space width (Δ = 0.14 mm, P = 0.54) and amount of contrast material were not significant. Direct wrist MR arthrography with axial traction of 3 kg increases joint space width at the radiocarpal and lunocapitate spaces, and prompts better coverage of the articular cartilage by the contrast material.
    Journal of Magnetic Resonance Imaging 07/2011; 34(1):239-44. · 2.57 Impact Factor
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    Skeletal Radiology 06/2011; · 1.74 Impact Factor
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    ABSTRACT: KeywordsFinger osteoid osteoma radiographs–curettage
    Skeletal Radiology 06/2011; 40(11):1479-80, 1501-2. · 1.74 Impact Factor
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    ABSTRACT: Lumbar spinal stenosis (LSS) treatment is based primarily on the clinical criteria providing that imaging confirms radiological stenosis. The radiological measurement more commonly used is the dural sac cross-sectional area (DSCA). It has been recently shown that grading stenosis based on the morphology of the dural sac as seen on axial T2 MRI images, better reflects severity of stenosis than DSCA and is of prognostic value. This radiological prospective study investigates the variability of surface measurements and morphological grading of stenosis for varying degrees of angulation of the T2 axial images relative to the disc space as observed in clinical practice. Lumbar spine TSE T2 three-dimensional (3D) MRI sequences were obtained from 32 consecutive patients presenting with either suspected spinal stenosis or low back pain. Axial reconstructions using the OsiriX software at 0°, 10°, 20° and 30° relative to the disc space orientation were obtained for a total of 97 levels. For each level, DSCA was digitally measured and stenosis was graded according to the 4-point (A-D) morphological grading by two observers. A good interobserver agreement was found in grade evaluation of stenosis (k = 0.71). DSCA varied significantly as the slice orientation increased from 0° to +10°, +20° and +30° at each level examined (P < 0.0001) (-15 to +32% at 10°, -24 to +143% at 20° and -29 to +231% at 30° of slice orientation). Stenosis definition based on the surface measurements changed in 39 out of the 97 levels studied, whereas the morphology grade was modified only in two levels (P < 0.01). The need to obtain continuous slices using the classical 2D MRI acquisition technique entails often at least a 10° slice inclination relative to one of the studied discs. Even at this low angulation, we found a significantly statistical difference between surface changes and morphological grading change. In clinical practice, given the above findings, it might therefore not be necessary to align the axial cuts to each individual disc level which could be more time-consuming than obtaining a single series of axial cuts perpendicular to the middle of the lumbar spine or to the most stenotic level. In conclusion, morphological grading seems to offer an alternative means of assessing severity of spinal stenosis that is little affected by image acquisition technique.
    European Spine Journal 06/2011; 21 Suppl 6:S760-4. · 2.13 Impact Factor
  • Spine Journal - SPINE J. 01/2011; 11(10).
  • Y. Eggel, F. Luthi, N. Theumann
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    ABSTRACT: Les rétinoïdes sont des médicaments efficaces dans le traitement de l’acné sévère. Leur utilisation peut cependant induire de nombreux effets secondaires. De rares épiphysiodèses prématurées ont été rapportées. Nous présentons le cas d’un jeune footballeur qui avait consulté pour des douleurs antérieures progressives. L’anamnèse médicamenteuse révélait l’utilisation d’isotrétinoïne. L’IRM montrait une irrégularité du cartilage de conjugaison et un important œdème métaphyso-épiphysaire, plus marqué au genou gauche. Le diagnostic d’épiphysiodèse induite par la prise de rétinoïde était retenu. Le traitement était stoppé, avec une résolution des symptômes en deux mois. Après guérison, une image en empreinte de pouce de la plaque de croissance persistait à l’IRM de contrôle. Les rétinoïdes provoquent une invasion de la plaque de conjugaison par des ostéoclastes et une diminution de synthèse de protéoglycans. Le genou semble l’articulation la plus touchée. Cette complication étant rare, un suivi radiologique des jeunes patients traités par rétinoïdes n’est cependant pas proposé.
    Annals of Physical and Rehabilitation Medicine. 01/2011; 54.
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    ABSTRACT: Retrospective radiologic study on a prospective patient cohort. To devise a qualitative grading of lumbar spinal stenosis (LSS), study its reliability and clinical relevance. Radiologic stenosis is assessed commonly by measuring dural sac cross-sectional area (DSCA). Great variation is observed though in surfaces recorded between symptomatic and asymptomatic individuals. We describe a 7-grade classification based on the morphology of the dural sac as observed on T2 axial magnetic resonance images based on the rootlet/cerebrospinal fluid ratio. Grades A and B show cerebrospinal fluid presence while grades C and D show none at all. The grading was applied to magnetic resonance images of 95 subjects divided in 3 groups as follows: 37 symptomatic LSS surgically treated patients; 31 symptomatic LSS conservatively treated patients (average follow-up, 2.5 and 3.1 years); and 27 low back pain (LBP) sufferers. DSCA was also digitally measured. We studied intra- and interobserver reliability, distribution of grades, relation between morphologic grading and DSCA, as well relation between grades, DSCA, and Oswestry Disability Index. Average intra- and interobserver agreement was substantial and moderate, respectively (k = 0.65 and 0.44), whereas they were substantial for physicians working in the study originating unit. Surgical patients had the smallest DSCA. A larger proportion of C and D grades was observed in the surgical group. Surface measurements resulted in overdiagnosis of stenosis in 35 patients and under diagnosis in 12. No relation could be found between stenosis grade or DSCA and baseline Oswestry Disability Index or surgical result. C and D grade patients were more likely to fail conservative treatment, whereas grades A and B were less likely to warrant surgery. The grading defines stenosis in different subjects than surface measurements alone. Since it mainly considers impingement of neural tissue it might be a more appropriate clinical and research tool as well as carrying a prognostic value.
    Spine 10/2010; 35(21):1919-24. · 2.16 Impact Factor
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    ABSTRACT: To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA). In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated. Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%. Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA.
    European Radiology 05/2010; 20(10):2439-46. · 3.55 Impact Factor

Publication Stats

577 Citations
187.69 Total Impact Points

Institutions

  • 1999–2013
    • University Hospital of Lausanne
      • Service de radiodiagnostic et radiologie interventionnelle
      Lausanne, Vaud, Switzerland
  • 2012
    • Clinique Bois-Cerf, Lausanne
      Lausanne, Vaud, Switzerland
  • 2011
    • Clinique romande de réadaptation
      Sitten, Valais, Switzerland
  • 2008
    • Université René Descartes - Paris 5
      • Faculté de Médecine
      Lutetia Parisorum, Île-de-France, France