[Monoclonal gammopathy of undetermined significance : when and why to look for them ?] / Les gammapathies monoclonales de signification indéterminée : quand et pourquoi les chercher ?

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic premalignant plasma cell disorder. MGUS is a common disorder and the diagnosis is often made accidentally when a protein electrophoresis is performed in a routine blood test or during a biological assessment for other conditions. In the absence of biological abnormalities or clinical symptoms suggesting a plasma or lymphoplasma-cell disorder, there is no indication for routine screening of the monoclonal protein. When MGUS is diagnosed, the risk of transformation into myeloma or other lymphoproliferative disorders is estimated at 1 % per year. MGUS can also be associated with diseases that are not malignant disorders and in some cases, the monoclonal gammopathy is the witness of another rare but severe disorder wich will be critical not to be missdiagnosed.

La gammapathie monoclonale de signification indéterminée (MGUS) est une anomalie biologique asymptomatique dont le diagnostic est souvent posé lors d'un bilan réalisé en routine ou pour d'autres symptômes que ceux requérant cette analyse. L'incidence des MGUS est évaluée à au moins 3 % au-dessus de 50 ans et sa fréquence continue à augmenter avec l'âge. La majorité des patients avec une MGUS n'évoluera jamais vers une hémopathie et en l'absence d'anomalies biologiques ou de symptômes évoquant une maladie associée à une immunoglobuline monoclonale, il n'y a pas d'indication d'effectuer une électrophorèse des protéines. Si le diagnostic de MGUS est posé, le risque d'évolution vers un myélome ou une autre hémopathie maligne est de 1 % par an. Une MGUS peut aussi être associée à des pathologies non malignes ou être le reflet d'autres maladies rares et graves dont il est capital de ne pas rater le diagnostic.

[Diagnostic approach of an IgM monoclonal gammopathy and clinical importance of gene MYD88 L265P mutation]. / Approche diagnostique d'une gammapathie monoclonale à IgM et intérêt clinique de la recherche de la mutation L265P du gène MYD88.

INTRODUCTION: An IgM monoclonal gammopathy points to a diagnosis of Waldenstrom's Macroglobulinemia. Other B lymphoproliferatives disorders should be ruled out but the limits are sometimes difficult to define. The discovery of the L265P mutation of the MYD88 gene simplified potentially the situation. POPULATION AND METHODS: 383 patients of the Jules Bordet Institute with an IgM level above 2 g/L were reviewed. For the 49 who had a monoclonal peak, we analysed the underlying pathology in termes of general, clinical and biological characteristics. We checked if the MYD88 mutation had been detected. The overall survival rate was studied. RESULTS: 5 histological groups were identified: Waldenstrom's Macroglobulinemia (MW, N = 27), lymphoplasmacytic lymphoma (LLP, N = 10), marginal zone lymphoma (LMZ, N = 7), monoclonal gammopathy of unknown significance and multiple myeloma (MGUS/MM, N = 5). The MW group was compared to the other groups. Regarding biological characteristics, the IgM level upon diagnosis was statistically higher in the MW group with a median level at 19.5 g/L (2.3-101 g/L) (p-value = 0,0001). Concerning the clinical characteristics, a splenomegaly was more frequent in the LMZ group (p-value = 0,04). The L265P mutation of the MYD88 gene was found in 77 % of patients in the MW group, 60 % of patients in the LLP group and 67 % in the LMZ group (p-value = 0,38). For the 49 patients, the 10-yearoverall survival was 85 % (CI 95 %, 67 % to 94 %) and the 15-year-overall survival was 65 % (CI 95 %, 41 % to 81 %). CONCLUSION: A monoclonal IgM peak suggests a MW but other B lymphoproliferatives disorders should be excluded. Even if the L265P mutation is frequent in the LLP/MW, it is not specific. A precise diagnosis requires collating clinical, histological, immunophenotypical and genetical data.

INTRODUCTION: Une gammapathie monoclonale à IgM évoque généralement le diagnostic de maladie de Waldenström. D'autres syndromes lymphoprolifératifs B doivent être exclus mais les " frontières " entre les différentes entités sont parfois mal définies. La découverte de la mutation L265P du gène MYD88 a potentiellement simplifié cette situation. Population et méthodes : 383 patients de l'Institut Jules Bordet présentant un taux d'IgM supérieur à 2 g/L ont été étudiés. 49 d'entre eux présentaient un pic monoclonal pour lesquels nous avons réalisé l'analyse de la pathologie sous-jacente en terme de caractéristiques générales, cliniques et biologiques et avons identifié si une recherche de mutation MYD88 avait été réalisée. La survie globale a également été étudiée. Résultats : 5 groupes histologiques ont été identifiés : maladie de Waldenström (MW, N = 27), lymphome lymphoplasmocytaire (LLP, N = 10), lymphomes de la zone marginale (LMZ ; tous types confondus, N = 7), gammapathie monoclonale de signification indéterminée et myélome multiple (MGUS/MM, N = 5). Le groupe MW a été comparé aux autres groupes. En terme de caractéristiques biologiques, c'est le taux d'IgM au diagnostic qui est statistiquement plus élevé dans le groupe MW avec un taux médian de 19,5 g/L (2,3-101 g/L) (p-valeur = 0,001). Concernant les caractéristiques cliniques, une splénomégalie est plus souvent présente dans le groupe LMZ (p-valeur = 0,04). La mutation L265P du gène MYD88 est retrouvée chez 77 % des patients du groupe MW, 60 % des patients du groupe LLP et 67 % des patients du groupe LMZ (p-valeur = 0,38). La survie globale des 49 patients est de 85 % à 10 ans (IC 95 %, 67 % à 94 %) et de 65 % à 15 ans (IC 95 %, 41 % à 81 %). CONCLUSION: Un pic d'IgM monoclonal évoque généralement une MW, mais il faut toujours exclure d'autres syndromes lymphoprolifératifs B. Alors que la mutation L265P du gène MYD88 est fortement exprimée chez les patients porteurs d'un LLP/MW, elle n'en est pas pour autant spécifique. Un diagnostic précis nécessite aujourd'hui d'intégrer les données cliniques, histologiques, immunophénotypiques et génétiques.

Depth and lateral deviations in guided implant surgery: an RCT comparing guided surgery with mental navigation or the use of a pilot-drill template.

AIM: To assess the accuracy of guided surgery compared with mental navigation or the use of a pilot-drill template in fully edentulous patients. MATERIAL AND METHODS: Sixty consecutive patients (72 jaws), requiring four to six implants (maxilla or mandible), were randomly assigned to one of the following treatment modalities: Materialise Universal(®) mucosa, Materialise Universal(®) bone, Facilitate(™) mucosa, Facilitate(™) bone, mental navigation, or a pilot-drill template. Accuracy was assessed by matching the planning CT with a postoperative CBCT. Deviations were registered in a vertical (depth) and horizontal (lateral) plane. The latter further subdivided into BL (bucco-lingual) and MD (mesio-distal) deviations. RESULTS: The overall mean vertical deviation for the guided surgery groups was 0.9 mm ± 0.8 (range: 0.0-3.7) and 0.9 mm ± 0.6 (range: 0.0-2.9) in a horizontal direction. For the non-guided groups, this was 1.7 mm ± 1.3 (range: 0.0-6.4) and 2.1 mm ± 1.4 (range 0.0-8.5), respectively (P < 0.05). The overall mean deviation for the guided surgery groups in MD direction was 0.6 mm ± 0.5 (range: 0.0-2.5) and 0.5 mm ± 0.5 (range: 0.0-2.9) in BL direction. For the non-guided groups, this was 1.8 mm ± 1.4 (range: 0.0-8.3) and 0.7 mm ± 0.6 (range 0.0-2.9), respectively. The deviation in MD direction was significantly higher in the non-guided groups (P = 0.0002). CONCLUSION: The most important inaccuracy with guided surgery is in vertical direction (depth). The inaccuracy in MD or BL direction is clearly less. For non-guided surgery, the inaccuracy is significantly higher.

Accuracy of computer-aided implant placement.

AIM: To assess the accuracy of static computer-guided implant placement. MATERIAL AND METHODS: Electronic and manual literature searches were conducted to collect information on the accuracy of static computer-guided implant placement and meta-regression analyses were performed to summarize and analyse the overall accuracy. The latter included a search for correlations between factors such as: support (teeth/mucosa/bone), number of templates, use of fixation pins, jaw, template production, guiding system, guided implant placement. RESULTS: Nineteen accuracy studies met the inclusion criteria. Meta analysis revealed a mean error of 0.99 mm (ranging from 0 to 6.5 mm) at the entry point and of 1.24 mm (ranging from 0 to 6.9 mm) at the apex. The mean angular deviation was 3.81° (ranging from 0 to 24.9°). Significant differences for all deviation parameters was found for implant-guided placement compared to placement without guidance. Number of templates used was significant, influencing the apical and angular deviation in favour for the single template. Study design and jaw location had no significant effect. Less deviation was found when more fixation pins were used (significant for entry). CONCLUSION: Computer-guided implant placement can be accurate, but significant deviations have to be taken into account. Randomized studies are needed to analyse the impact of individual parameters in order to allow optimization of this technique. Moreover, a clear overview on indications and benefits would help the clinicians to find the right candidates.

Model-based guided implant insertion for solitary tooth replacement: a pilot study.

OBJECTIVE: The impact of the implant position on the restorative outcome could justify guided surgery even for the single implants particularly in the aesthetic zone and especially when a simplified concept is available. MATERIAL AND METHODS: Based on a plaster model, on which the soft tissues were mimicked (according to the thickness measured on a Cone-Beam CT), a tooth-supported, surgical template was prepared. The latter guided all drills so that even flapless implant insertion became possible. All implants were placed by students of the master-after-master training program in Periodontology. RESULTS: The prospective cohort included a total of 34 implants, all of AstraTech (Osteospeed(®)) type, which were successfully inserted in 29 patients, 16 flapless, 32 onestage. The marginal bone along the integrated implants remained stable over time, with 0.13 mm loss during the first year. The aesthetic parameters were reassuring. CONCLUSIONS: This simple model-based concept seems to be reliable for the guided placement of single implants and the pre-operative preparation of their restorations.

Management of rectal foreign bodies.

The presence of foreign bodies inserted into the rectum is not an uncommon situation. Precise guidelines for the management and extraction of these foreign bodies are not frequently described in the literature. Anal access, whether endoscopic or surgical, varies depending on the type of foreign bodies, their size and morphology, and their location in the lower digestive tract In this report, we describe a case of three rectal foreign bodies that necessitated a mixed endoscopic and surgical approach, and provide a review of the literature.

Long-term, retrospective evaluation (implant and patient-centred outcome) of the two-implant-supported overdenture in the mandible. Part 2: marginal bone loss.

OBJECTIVE: In part 2 of this long-term, retrospective study on the two-implant-supported overdenture in the mandible, the annual marginal bone loss was evaluated in detail and parameters, with a significant effect on the annual bone loss, were verified. MATERIAL AND METHODS: For all 495 patients with an overdenture in the mandible at least 5 years in function, data up to their last follow-up visit had been collected, including long-cone radiographs (taken at the abutment connection and after years 1, 3, 5, 8, 12 and 16 of loading) and probing data at their last evaluation. General information (medical history, implant data, report on surgery) was retrieved from the patient's file. Two hundred and forty-eight patients had been clinically examined recently. For the others, information on bone level and probing depths were retrieved from the patient's files, as all patients had been enrolled in our annual follow-up schedule. RESULTS: The mean annual bone loss on a site level (without considering the first year of bone remodelling) after 3 years of loading was 0.08 mm/year (SD=0.22, n=1105), after 5 years of loading 0.07 mm/year (SD=0.14, n=892), after 8 years of loading 0.06 mm/year (SD=0.12, n=598), after 12 years 0.04 mm/year (SD=0.07, n=370) and 0.05 mm/year (SD=0.05, n=154) after 16 years of loading. Ongoing bone loss was seen in a number of implants (n=26) with the annual bone loss exceeding 0.2 mm. Some factors clearly showed a significant impact on bone loss: smoking (> or =10 cigarettes/day), GBR, the presence of dehiscence and bone quantity(the latter only during the first year). The probing data showed a favourable condition, with <1.2% of the approximal pockets being > or =6 mm, and 4.1%=5 mm. CONCLUSIONS: The mean annual bone loss over the study period was <0.1 mm/year after the first year of loading. However, a small number (2.5%) of the implants showed continuing bone loss.

Long-term, retrospective evaluation (implant and patient-centred outcome) of the two-implants-supported overdenture in the mandible. Part 1: survival rate.

OBJECTIVE: This retrospective analysis evaluated the long-term outcome of two implants supporting an overdenture in the mandible, as well as the significance of some confounding factors (smoking, implant length, bone quality). MATERIAL AND METHODS: All mandibular overdenture cases (n=495) treated during the past 25 years in our centre (with > or = 5 years loading of the implants) were included in this study. General information (medical history, implant data, report on surgery) was retrieved from the patient's file. A large number of patients (n=248) were willing to visit the clinic for an additional follow-up visit. For the others, information on implant survival was collected by phone (n=121), or contact was impossible (57 had died, three were hospitalized and 66 could not be reached). In the latter group, information was used, up to their last visit to the clinic. An implant was considered as surviving if it was still in function in the mouth, without clear adverse effects (pain, swelling, mobility). A failure was defined as early if it occurred within the window, insertion-final prosthesis placement; afterwards, it was considered as late. RESULTS: Most of the inserted implants (Brånemark type) were of the turned (machined) type (95.5%), the remainder was anodized (TiUnite). The anchoring system was either a bar (86.3%), ball attachments (11.7%) or magnets (1.6%), and only some patients changed from one to the other (0.4%). Kaplan-Meier analyses showed a survival rate of 95.5% after 20 years of loading. Factors that influenced the outcome included smoking (90% rate for smokers) and the surgical protocol (reduced survival rate for one-stage-placed implants). Implant length and bone quality had no impact. CONCLUSIONS: These results fully support the two-implant overdenture concept in the mandible even in the long run.

The use of CT scan based planning for oral rehabilitation by means of implants and its transfer to the surgical field: a critical review on accuracy.

The purpose of the present paper is to review the literature on the use of CT scan based planning for oral rehabilitation and its transfer to the surgical field by means of a surgical guide. The first part will deal with surgical guides based on tomographies or CT scan data often using dedicated software, but manually fabricated. In the second part, CT-derived drill guides are discussed, which are fabricated by means of CAD/CAM technology or other computer-controlled technology. The deviations between the position of the implants at the planning stage and after the surgery are of utmost importance, especially when flapless procedures are applied. The maximal deviations are often not stated in the literature. This should be taken into account when a system is applied clinically.

Analysis of whole-arm translocations in malignant blood cells by nonisotopic in situ hybridization.

Whole-arm translocations in five leukemic patients were studied using nonisotopic in situ hybridization with alpha satellite DNA and simple satellite chromosome-specific DNA probes to detect the target sequences. The results show that this technique provides additional information on the involvement of these DNA sequences in whole-arm translocations.