Assessing the external validity and clinical relevance of umbilical doppler resistance index references in daily practice.

OBJECTIVE: To assess the external validity and clinical relevance of current references for umbilical artery resistance index (UA RI) in daily practice. METHODS: Retrospective cross-sectional single center study including all UA RI measurements between 22 and 40 gestational weeks (GW) from distinct patients between 2014 and 2022. Patients with normal pregnancies and normal neonatal outcomes that had an UA RI measurement between 2014 and 2019 were used to calculate reference ranges. The established reference for the 95th centile was compared to two current references. The clinical relevance of the established reference was tested by comparing neonatal outcomes according to the 95th percentile among the consecutive distinct patients between 2020 and 2022. RESULTS: Among the 13342 consecutive distinct patients with a singleton pregnancy that had an UA RI measurement between 22 and 40 GW between 2014 and 2022, 5298 patients were included to establish the reference ranges, and 3634 patients to validate these ranges. For each gestational age, the established references were similar to current references. Using the established references, the proportion of patients presenting an UA RI>95th percentile among the patients with normal pregnancies in the validation population was comparable to the proportion when using the two current references. Among the validation population, 268 patients (7.4 %) (95%CI[6.5-8.2]) presented an UA RI ≥ 95th percentile. Of these 268 patients, 67.9% had a SGA newborn (versus 19.2%, p<0.001) and 59% a preterm birth (versus 13.9%, p<0.001). CONCLUSIONS: The reference range obtained from daily practice is clinically relevant and similar to current references.

Neu Laxova syndrome and megacystis in the first trimester: Broadening the fetal phenotype.

Neu Laxova syndrome (NLS) is a rare and lethal congenital disorder characterized by severe intra-uterine growth retardation (IUGR), ichthyosis, abnormal facial features, limb abnormalities with arthrogryposis and a wide spectrum of severe malformations of the central nervous system (CNS). NLS is due to biallelic variants in three genes previously involved in serine-deficiency disorders (PHGDH, PSAT1 and PSPH), extending the phenotypic spectrum of these disorders.

Biochemical Screening for Fetal Trisomy 21: Pathophysiology of Maternal Serum Markers and Involvement of the Placenta.

It is now well established that maternal serum markers are often abnormal in fetal trisomy 21. Their determination is recommended for prenatal screening and pregnancy follow-up. However, mechanisms leading to abnormal maternal serum levels of such markers are still debated. Our objective was to help clinicians and scientists unravel the pathophysiology of these markers via a review of the main studies published in this field, both in vivo and in vitro, focusing on the six most widely used markers (hCG, its free subunit hCGß, PAPP-A, AFP, uE3, and inhibin A) as well as cell-free feto-placental DNA. Analysis of the literature shows that mechanisms underlying each marker's regulation are multiple and not necessarily directly linked with the supernumerary chromosome 21. The crucial involvement of the placenta is also highlighted, which could be defective in one or several of its functions (turnover and apoptosis, endocrine production, and feto-maternal exchanges and transfer). These defects were neither constant nor specific for trisomy 21, and might be more or less pronounced, reflecting a high variability in placental immaturity and alteration. This explains why maternal serum markers can lack both specificity and sensitivity, and are thus restricted to screening.

Percreta score to differentiate between placenta accreta and placenta percreta with ultrasound and MR imaging.

INTRODUCTION: The objective of this study was to assess the performance of ultrasound and magnetic resonance imaging (MRI) features in helping to classify the type of placenta accreta spectrum (PAS; accreta/increta vs percreta), alone or combined in a predictive score. MATERIAL AND METHODS: We conducted a retrospective study in 82 pregnant women with PAS who underwent ultrasound and MRI examination of the pelvis before delivery (from an initial cohort of 185 women with PAS). We estimated the sensitivity, specificity and accuracy of MRI and ultrasound in the diagnosis of the type of PAS. We analyzed cesarean and imaging features using univariable logistic regression analysis. We constructed a nomogram to predict the risk of placenta percreta and validated it with bootstrap resampling, then used receiver operating characteristic curves to assess the performance of the model in distinguishing between placenta percreta and placenta accreta/increta. RESULTS: Among the 82 patients, 29 (35%) had placenta accreta/increta and 53 (65%) had placenta percreta. The best features to discriminate between placenta accreta/increta and placenta percreta with ultrasound were increased vascularization at the uterine serosa-bladder wall interface (odds ratio [OR] 7.93; 95% confidence interval [CI] 2.78-24.99; p < 0.01) and the number of lacunae without a hyperechogenic halo (OR 1.36; 95% CI 1.14-1.67; p = 0.012). Concerning MRI markers, heterogeneous placenta (OR 12.89; 95% CI 3.05-89.16; p = 0.002), dark intraplacental bands (OR 12.89; 95% CI 3.05-89.16; p = 0.002) and bladder wall interruption (OR 15.89; 95% CI 4.78-73.33; p < 0.001) had a higher OR in discriminating placenta accreta/increta from placenta percreta. The nomogram yielded areas under the curve of 0.841 (95% CI 0.754-0.927) and 0.856 (95% CI 0.767-0.945), after bootstrap resampling, for the accurate prediction of placenta percreta. CONCLUSIONS: The nomogram we developed to predict the risk of placenta percreta among patients with PAS had good discriminative capabilities. This performance and its impact on maternal morbidity should be confirmed by future prospective studies.

Megacystis in the first trimester of pregnancy: Prognostic factors and perinatal outcomes.

OBJECTIVE: To determine whether bladder size is associated with an unfavorable neonatal outcome, in the case of first-trimester megacystis. MATERIALS AND METHODS: This was a retrospective observational study between 2009 and 2019 in two prenatal diagnosis centers. The inclusion criterion was an enlarged bladder (> 7 mm) diagnosed at the first ultrasound exam between 11 and 13+6 weeks of gestation. The main study endpoint was neonatal outcome based on bladder size. An adverse outcome was defined by the completion of a medical termination of pregnancy, the occurrence of in utero fetal death, or a neonatal death. Neonatal survival was considered as a favorable outcome and was defined by a live birth, with or without normal renal function, and with a normal karyotype. RESULTS: Among 75 cases of first-trimester megacystis referred to prenatal diagnosis centers and included, there were 63 (84%) adverse outcomes and 12 (16%) live births. Fetuses with a bladder diameter of less than 12.5 mm may have a favorable outcome, with or without urological problems, with a high sensitivity (83.3%) and specificity (87.3%), area under the ROC curve = 0.93, 95% CI (0.86-0.99), p< 0.001. Fetal autopsy was performed in 52 (82.5%) cases of adverse outcome. In the 12 cases of favorable outcome, pediatric follow-up was normal and non-pathological in 8 (66.7%). CONCLUSION: Bladder diameter appears to be a predictive marker for neonatal outcome. Fetuses with smaller megacystis (7-10 mm) have a significantly higher chance of progressing to a favorable outcome. Urethral stenosis and atresia are the main diagnoses made when first-trimester megacystis is observed. Karyotyping is important regardless of bladder diameter.

Amniotic Aaquaporins (AQP) in Normal and Pathological Pregnancies: Interest in Polyhydramnios.

Polyhydramnios is a common feature diagnosed by ultrasound in the second half of pregnancy. Biochemical analysis of amniotic fluid can be useful when suspecting Bartter syndrome or digestive atresia but in most of cases, no etiology of polyhydramnios is found because of the complex regulation of amniotic fluid. Aquaporins (AQP) are transmembrane channel proteins contributing to water transfers. Some of them are expressed in fetal membranes and placenta. Their expression has been shown to be disrupted in some pathological conditions such as maternal diabetes, often associated with polyhydramnios. AQP-1, 3 and 8 levels in amniotic fluid were retrospectively measured in patients suffering from polyhydramnios (n=21) from 23 weeks of gestation (WG). They were compared to the levels observed in control subjects (n=96) and their relationship with maternal factors and neonatal issues was analyzed. AQP-1, 3, 8 levels were physiologically fluctuating, AQP-1 levels always being the lowest and AQP-3 the highest, with a significant decrease at the end of pregnancy. AQPs/AFP ratios increased about 8 folds during pregnancy, their kinetic profiles reflecting physiological dynamic evolution of amniotic fluid volume. In polyhydramnios, AQP-3 level tended to be decreased whereas AQP-8 level was decreased from mid-gestation whatever the etiology of polyhydramnios. No significant relationship was found between AQPs levels and either the fetal prematurity degree or macrosomia. No specific pattern was observed in idiopathic polyhydramnios, limiting the interest of AQPs dosage in amniotic fluid in the management of those complicated pregnancies.

Early surgical management for giant omphalocele: Results and prognostic factors.

OBJECTIVES: Giant omphalocele often represents a major surgical challenge and is reported with high mortality and morbidity rates. The aim of this study was to assess the outcome of neonates with giant omphalocele managed with early operative surgical treatment, and subsequently to identify possible factors that could alter the prognosis. METHODS: We reviewed the medical records of 29 consecutive newborns with prenatally diagnosed giant omphalocele. In these cases one of two procedures had been performed: either staged closure after silo, or immediate closure with a synthetic patch. The cases were separated into 2 groups: Isolated giant omphalocele (IO group) and giant omphalocele associated with malformation (NIO group). RESULTS: Infants in the IO group had a lower size of the omphalocele (p<0,001), a shorter hospital stay (95 days [45-915] vs. 41.5 days [10-110] p= 0, 02), and a shorter median ventilation length (10 days [1-33] vs. 27, 5 [6-65] p = 0, 05). In the NIO group, 5 cases displayed a significantly more difficult course than the others. They were compared to the remaining cases for prenatal and anatomic features. Four factors associated with greater morbidity were identified: CONCLUSIONS: Isolated omphalocele, even containing the whole liver, has a very good prognosis with early surgical treatment. Without associated anomalies, 95% of giant omphaloceles can be discharged with a median of 41.5 days in hospital. However, associated anomalies (especially cardiopathies) may burden the prognosis and should be both carefully assessed during pregnancy and taken into account in parental information. TYPE OF STUDY: Retrospective Study LEVEL OF EVIDENCE: Level I.

Placenta percreta is associated with more frequent severe maternal morbidity than placenta accreta.

BACKGROUND: Abnormally invasive placentation is the leading cause of obstetric hysterectomy and can cause poor to disastrous maternal outcomes. Most previous studies of peripartum management and maternal morbidity have included variable proportions of severe and less severe cases. OBJECTIVE: The aim of this study was to compare maternal morbidity from placenta percreta and accreta. STUDY DESIGN: This retrospective study at a referral center in Paris includes all women with abnormally invasive placentation from 2003 through 2017. Placenta percreta and accreta were diagnosed histologically or clinically. When placenta percreta was suspected before birth, a conservative approach leaving the placenta in situ was proposed because of the intraoperative risk of cesarean delivery. When placenta accreta was suspected, parents were offered a choice of a conservative approach or an attempt to remove the placenta, to be followed in case of failure by hysterectomy. Maternal outcomes were compared between women with placenta percreta and those with placenta accreta/increta. The primary outcome measure was a composite criterion of severe acute maternal morbidity including at least 1 of the following: hysterectomy during cesarean delivery, delayed hysterectomy, transfusion of ≥10 U of packed red blood cells, septic shock, acute kidney injury, cardiovascular failure, maternal transfer to intensive care, or death. RESULTS: Of the 156 women included, 51 had placenta percreta and 105 placenta accreta. Abnormally invasive placentation was suspected antenatally nearly 4 times more frequently in the percreta than the accreta group (96.1% [49/51] vs 25.7% [27/105], P < .01). Among the 76 women with antenatally suspected abnormally invasive placentation (48.7%), the rate of antenatal decisions for conservative management was higher in the percreta than the accreta group (100% [49/49] vs 40.7% [11/27], P < .01). The composite maternal morbidity rate was significantly higher in the percreta than the accreta group (86.3% [44/51] vs 28/105 [26.7%], P < .001). A secondary analysis restricted to women with an abnormally invasive placentation diameter >6 cm showed similar results (86.0% [43/50) vs 48.7% [19/38), P < .01). The rate of hysterectomy during cesareans was significantly higher in the percreta than the accreta group (52.9% [27/51] vs 20.9% [22/105], P < .01) as was the total hysterectomy rate (43/51 [84.3%] vs 23.8% [25/105], P < .01). CONCLUSION: Severe maternal morbidity is much more frequent in women with placenta percreta than with placenta accreta, despite multidisciplinary planning, management in a referral center, and better antenatal suspicion.

[Labour in women with scarred uterus in the Democratic Republic of the Congo: trial of scar and factors influencing the outcome]. / Accouchements sur utérus cicatriciel en République Démocratique du Congo: épreuve utérine et facteurs déterminants de l'issue.

OBJECTIVE: Our study aims to identify risks factors associated with failed trial of scar and to set a predictive score of labour in women with scarred uterus in the Democratic Republic of the Congo. METHODS: We conducted a multicenter cross-sectional analytic study of patients with scarred uterus in four maternity units in the Democratic Republic of the Congo (DRC) from 1 January to 31 December 2013. Logistic regression model was used to identify factors associated with failed trial of scar. We set a predictive score based on this model in order to predict trial of scar failure in maternity units in the DRC. ROC curve was used to assess the ability of the set score to identify patients at risk for trial of scar failure. The cut off point for the predictive score was determined on the basis of the Youden-index-based optimal sensitivity and specificity. All the tests in our study were carried out by using a significance threshold of α=0.05. RESULTS: Two explanatory factors in trial of scar failure were retained. They were the socio-demographic factor (maternal age) and three obstetric factors (fundal height, fetal presentation and premature rupture of membranes). Predictive score was set to predict trial of scar failure. This score was determined based on four elements: maternal age, evaluation of the gestational sac on admission, fundal height and fetal presentation. The minimum score was set at 4 and the maximum score was set at 16. The threshold value was set at 7. A total score greater than or equal to 7 reflects a risk of trial of scar failure. CONCLUSION: We set a predictive score to predict trial of scar failure. This score was determined based on four elements: maternal age, evaluation of the gestational sac on admission, fundal height and fetal presentation. A total score greater than or equal to 7 reflects a risk of trial of scar failure.

[SMOKING CESSATION IN PREGNANCY]. / Sevrage tabagique chez la femme enceinte.

Smoking during pregnancy is the leading preventable cause of perinatal morbidity. Half of smokers are weaned during pregnancy resulting in 15% of female smokers at time of delivery. Most often, women spontaneously withdraw at the announcement of pregnancy. Thus, the action of professionals has a modest effect. But this effect is real and should encourage us to take care for patients who smoke. They should feel free with guilty. The spouse must be included in this support to create an enabling environment. Every action has its effectiveness. Nicotine prescription should be reserved for cases where it reduces consumption and keep the medicalized link. It is possible to smoke with a nicotine patch in place; the substitution then reduces the cosumption of each cigarette.

Assessment of the Cervix in Pregnant Women Using Shear Wave Elastography: A Feasibility Study.

The quantitative assessment of the cervix is crucial for the estimation of pre-term delivery risk and the prediction of the success of labor induction. We conducted a cross-sectional study using shear wave elastography based on the supersonic shear imaging technique. The shear wave speed (SWS) of the lower anterior part of the cervix was quantified over an 8-mm region of interest in 157 pregnant women. Cervical SWS is slightly but significantly reduced in patients diagnosed with pre-term labor and in patients who actually delivered pre-term.

Segmentation of embryonic and fetal 3D ultrasound images based on pixel intensity distributions and shape priors.

This paper presents a novel variational segmentation framework combining shape priors and parametric intensity distribution modeling for extracting the fetal envelope on 3D obstetric ultrasound images. To overcome issues related to poor image quality and missing boundaries, we inject three types of information in the segmentation process: tissue-specific parametric modeling of pixel intensities, a shape prior for the fetal envelope and a shape model of the fetus' back. The shape prior is encoded with Legendre moments and used to constraint the evolution of a level-set function. The back model is used to post-process the segmented fetal envelope. Results are presented on 3D ultrasound data and compared to a set of manual segmentations. The robustness of the algorithm is studied, and both visual and quantitative comparisons show satisfactory results obtained by the proposed method on the tested dataset.

Conservative management of an advanced abdominal pregnancy at 22 weeks.

Objective We report an uneventful conservative approach of an advanced abdominal pregnancy discovered at 22 weeks of gestation. Study Design This study is a case report. Results Attempting to extend gestation of an advanced abdominal pregnancy is not a common strategy and is widely questioned. According to the couple's request, the management consisted in continuous hospitalization, regular ultrasound scan, and antenatal corticosteroids. While the woman remained asymptomatic, surgery was planned at 32 weeks, leading to the birth of a preterm child without any long-term complications. Placenta was left in situ with a prophylactic embolization, and its resorption was monitored. Conclusion Depending on multidisciplinary cares and agreement of the parents, when late discovered, prolonging advanced abdominal pregnancy appears to be a reasonable option.

Cerebral Doppler velocimetry to predict fetal anemia after more than three intravenous fetal exchange transfusions.

BACKGROUND: We aimed to assess usefulness of the middle cerebral artery peak systolic velocity (MCA-PSV) in the prediction of fetal anemia after more than three intravenous fetal-exchange transfusions (IFET). STUDY DESIGN AND METHODS: A retrospective study was conducted over 6 years of 15 consecutive pregnancies with severe red blood cell fetomaternal alloimmunization requiring more than three IFETs. We evaluated correlation between MCA-PSV (expressed as multiples of the mean [MoM]) and pretransfusion hemoglobin (Hb) in the fetus (MoM). Analyses were also performed to assess the value of MCA-PSV to predict moderate to severe fetal anemia. RESULTS: Twenty-seven MCA-PSV measurements performed before the fourth to last IFET were coupled with pretransfusion Hb in the fetus. The median number of IFETs per fetus was five (range, four to eight). Five Hb samples found fetuses with severe (19%), seven with moderate (26%), and 15 with mild anemia (56%). There was a linear correlation between MCA-PSV(x) and Hb in the fetus(y): y = -0.21x + 0.93 (r = -0.50, p < 0.01). For the prediction of moderate to severe anemia the negative predictive value of MCA-PSV with a threshold of 1.5 MoM was 75%, positive predictive value 73%, specificity 80%, sensibility 67%, and positive likelihood ratio 3.33. The area under the receiver operating characteristic curve was 0.78 (95% confidence interval, 0.59-0.96; p < 0.001). For the prediction of severe anemia, MCA-PSV with a threshold of 1.5 MoM had 94% negative predictive value, 80% sensibility, and a positive likelihood ratio of 2.5. CONCLUSIONS: This study shows that a correlation between MCA-PSV and Hb in the fetus persists even after more than three IFETs. MCA-PSV measurements thus remain useful to monitor fetuses at risk of anemia.

Nicotine patches in pregnant smokers: randomised, placebo controlled, multicentre trial of efficacy.

OBJECTIVE: To determine the efficacy of 16 hour nicotine patches among pregnant smokers, with the dose individually adjusted according to saliva cotinine levels (potential range 10-30 mg/day). DESIGN: Randomised, double blind, placebo controlled, parallel group, multicentre trial (Study of Nicotine Patch in Pregnancy, SNIPP) between October 2007 and January 2013. SETTING: 23 maternity wards in France. PARTICIPANTS: 476 pregnant smokers aged more than 18 years and between 12 and 20 weeks' gestation, who smoked at least five cigarettes a day. After exclusions, 402 women were randomised: 203 to nicotine patches and 199 to placebo patches. Data were available on 192 live births in each group. INTERVENTIONS: Nicotine and identical placebo patches were administered from quit day up to the time of delivery. Doses were adjusted to saliva cotinine levels when smoking to yield a substitution rate of 100%. Participants were assessed monthly and received behavioural smoking cessation support. MAIN OUTCOME MEASURES: The primary outcomes were complete abstinence (self report confirmed by carbon monoxide level in expired air ≤ 8 ppm) from quit date to delivery, and birth weight. The secondary outcomes were point prevalence of abstinence, time to lapse (a few puffs) or relapse, and delivery and birth characteristics. All data were analysed on an intention to treat basis. RESULTS: Complete abstinence was achieved by 5.5% (n=11) of women in the nicotine patch group and 5.1% (n=10) in the placebo patch group (odds ratio 1.08, 95% confidence interval 0.45 to 2.60). The median time to the first cigarette smoked after target quit day was 15 days in both groups (interquartile range 13-18 in the nicotine patch group, 13-20 in the placebo patch group). The point prevalence abstinence ranged from 8% to 12.5% in the nicotine patch group and 8% to 9.5% in the placebo patch group without statistically significant differences. The nicotine substitution rate did not differ from 100%, and the self reported median compliance rate was 85% (interquartile range 56-99%) in the nicotine patch group and 83% (56-95%) in the placebo patch group, assessed at 1016 visits. The mean birth weight was 3065 g (SE 44 g) in the nicotine patch group and 3015 g (SE 44 g) in the placebo patch group (P=0.41). Diastolic blood pressure was significantly higher in the nicotine patch group than in the placebo patch group. The frequency of serious adverse events was similar between the groups, although more non-serious adverse reactions, mainly of skin, occurred in the nicotine patch group. CONCLUSION: The nicotine patch did not increase either smoking cessation rates or birth weights despite adjustment of nicotine dose to match levels attained when smoking, and higher than usual doses. TRIAL REGISTRATION: ClinicalTrials.gov NCT00507975.

Hemodynamic impact of absent or reverse end-diastolic flow in the two umbilical arteries in growth-restricted fetuses.

OBJECTIVE: To determine if bilateral absent or reverse end-diastolic (ARED) flow in the two umbilical arteries (UAs) at the perivesical (PVC) segment represents a more severe degree of hemodynamic compromise than unilateral ARED flow at the PVC segment in singleton pregnancies complicated by intrauterine growth restriction (IUGR). METHODS: This was a prospective observational study. One hundred nine fetuses with IUGR underwent a total of 225 ultrasound (US) examinations. We measured the pulsatility index (PI) from the two UAs at the PVC segment, UA in the free floating cord (FFC), middle cerebral artery (MCA), ductus venosus (DV) and the aortic isthmus blood flow index (IFI). Three groups were classified according to bilateral positive end-diastolic (PED) flow, unilateral ARED flow or bilateral ARED flow in the UAs at the PVC segment. RESULTS: The proportions of US examinations with PED flow, unilateral ARED flow and bilateral ARED flow in the UAs were 54.7%, 20.4%, and 24.9%, respectively. At the last US examination, the IFI z-scores were significantly lower in the bilateral ARED group (-6.28 ± 4.30) compared to the unilateral ARED group (-1.72 ± 3.18, p<0.05) and the bilateral PED group (-0.83 ± 2.36, p<0.05), the DV-PI z-scores were significantly higher in the bilateral ARED group (2.15 ± 3.79) compared to the bilateral PED group (0.64 ± 1.50, p<0.05). Before 32 weeks of gestation, the interval between US examination and delivery was significantly shorter in the bilateral ARED group (8.9 days ± 8.2) than the unilateral ARED group (15.9 days ± 13.4, p<0.05) and the bilateral PED group (30.3 days ± 25.7, p<0.05). CONCLUSION: There are significant differences in fetal blood fluxes between left and right UA. Doppler examination at the PVC segment significantly improves the comparability of UA-PI between two successive US examinations and allows a longitudinal and independent hemodynamic investigation of each UA. Examination of a single UA in free floating cord may miss a large fraction of unilateral ARED flow. In singleton IUGR fetuses, a bilateral ARED flow in the UAs at the PVC segment indicates more severe hemodynamic compromise and worse fetal conditions than unilateral ARED flow.

Biomechanical simulation of the fetal descent without imposed theoretical trajectory.

The medical training concerning childbirth for young obstetricians involves performing real deliveries, under supervision. This medical procedure becomes more complicated when instrumented deliveries requiring the use of forceps or suction cups become necessary. For this reason, the use of a versatile, configurable childbirth simulator, taking into account different anatomical and pathological cases, would provide an important benefit in the training of obstetricians, and improve medical procedures. The production of this type of simulator should be generally based on a computerized birth simulation, enabling the computation of the reproductive organs deformation of the parturient woman and fetal interactions as well as the calculation of efforts produced during the second stage of labor. In this paper, we present a geometrical and biomechanical modeling of the main parturient's organs involved in the birth process, interacting with the fetus. Instead of searching for absolute precision, we search to find a good compromise between accuracy and model complexity. At this stage, to verify the correctness of our hypothesis, we use finite element analysis because of its reliability, precision and stability. Moreover, our study improves the previous work carried out on childbirth simulators because: (a) our childbirth model takes into account all the major organs involved in birth process, thus potentially enabling different childbirth scenarios; (b) fetal head is not treated as a rigid body and its motion is computed by taking into account realistic boundary conditions, i.e. we do not impose a pre-computed fetal trajectory; (c) we take into account the cyclic uterine contractions as well as voluntary efforts produced by the muscles of the abdomen; (d) a slight pressure is added inside the abdomen, representing the residual muscle tone. The next stage of our work will concern the optimization of our numerical resolution approach to obtain interactive time simulation, enabling it to be coupled to our haptic device.