The effect of frontal trauma on the edentulous mandible with four different interforaminal implant-prosthodontic anchoring configurations. A 3D finite element analysis.

PURPOSE: The present three-dimensional (3D) finite element analysis (FEA) was aimed to assess the biomechanical effects and fracture risks of four different interforaminal implant-prosthodontic anchoring configurations exposed to frontal trauma. MATERIAL AND METHODS: A symphyseal frontal trauma of 1 MPa was applied to four dental implant models with different configurations (two unsplinted interforaminal implants [2IF-U], two splinted interforaminal implants [2IF-S], four unsplinted interforaminal implants[ 4IF-U], four splinted interforaminal implants [4IF-S]. By using a 3D-FEA analysis the effective cortical bone stress values were evaluated in four defined regions of interest (ROI) (ROI 1: symphyseal area; ROI 2: preforaminal area; ROI 3: mental foraminal area; and ROI 4: condylar neck) followed by a subsequent intermodel comparison. RESULTS: In all models the frontal traumatic force application revealed the highest stress values in the condylar neck region. In both models with a four-implant configuration (4IF-U, 4IF-S), the stress values in the median mandibular body (ROI 1) and in the condylar neck region (ROI 4) were significantly reduced (P <0.01) compared with the two-implant models (2IF-U, 2IF-S). However, in ROI 1, the model with four splinted implants (4IF-S) showed significantly (P < 0.01) reduced stress values compared to the unsplinted model (4IF-U). In addition, all models showed increased stress patterns in the area adjacent to the posterior implants, which is represented by increased stress values for both 2IF-U and 2IF-S in the preforaminal area (ROI 3) and for the four implant-based models (4IF-U, 4IF-S) in the mental foraminal area. CONCLUSION: The configuration of four splinted interforaminal implants showed the most beneficial distribution of stress pattern representing reduced stress distribution and associated reduced fracture risk in anterior symphysis, condylar neck and preforaminal region.

Closure of the radial forearm free flap donor site with split-thickness skin graft or amniotic membrane: A prospective randomized clinical study.

The purpose of this study was to compare the clinical, aesthetic, and functional outcomes between amniotic membrane (test group) and split-thickness skin grafts (control group) used for radial forearm free flap defect closure. The primary outcome measurement for both groups was assessment of the defect closure healing process. In addition, aesthetic (Vancouver Scar Scale) and functional outcomes (skin sensitivity, hand/wrist functionality, grip strength) were evaluated. Fifty eligible patients with radial forearm free flap donor site defects were randomly assigned to two groups receiving either amniotic membrane (test group; n = 25) or split-thickness skin graft (control group; n = 25) for defect covering. Forty-seven of the 50 patients (n = 47) were able to be followed up for 6 months and showed a significantly longer healing process (p < 0.001) with amniotic membrane (64.5 ± 38.4 days; n = 24) than with split-thickness skin grafts (29.2 ± 8.9 days; n = 23); however, there were no differences in the prevalence of healing defects/dehiscence and/or wound infections. Forty-two of the 47 patients (21 in each group) were able to be continually followed up for 12 months, and showed no differences in terms of clinical outcome as well as the subjective and objective aesthetic and functional results evaluated. With regard to the clinical, aesthetic, and functional outcomes evaluated for radial forearm free flap defects, coverage with amniotic membrane offers an excellent alternative treatment approach, avoiding secondary induced donor site morbidity.

Use of amniotic membrane for radial forearm free flap donor site coverage: clinical, functional and cosmetic outcomes.

OBJECTIVE: To evaluate the clinical, functional and aesthetic outcomes for radial forearm free flap (RFFF) donor sites covered with amniotic membrane (AM). MATERIAL AND METHODS: The healing process of patients with RFFF donor sites covered with AM was prospectively followed for 1 year. Additionally at the 12-month evaluation, objective scoring systems were used to assess the aesthetic (Vancouver scar scale, VSS: range 1-13) and functional outcome (skin sensibility, hand/wrist functionality [goniometer], grip strength [score 1 = excellent, 5 = poor]). By using a subjective rating system (score 1 = excellent, 5 = poor), the patient-reported aesthetic and functionality outcome was correlated with objective data analysis. RESULTS: Twenty-one out of 23 patients were followed for 12 months (dropout: 2 patients at 3 months). In 17/23 (73.9%) patients RFFF defect covered with AM showed an uneventful healing period (< 3 months). Prolonged healing periods (> 3 months < 6) for 6 patients (26.1%) were attributed to wound infections (4×), seroma (1×) and inflammation (1×). At the 1-year evaluation, there was a significant (p < 0.01) correlation between subjective (2.0 ± 0.71) and objective aesthetic scores (VVS 3.74 ± 2.18), and a successful grip strength (score 1.67 ± 0.86); however, thumb hyposensibility in 76.2% was seen. A high body mass index (BMI) was in conjunction with a negative (p = 0.012) and the use of antihypertensive medications provided positive effects (p = 0.041) on the aesthetic outcome. CONCLUSION: RFFF donor site defects covered using AM show excellent clinical, aesthetic and functional outcome representing patient comorbidities (BMI, antihypertensive drugs) might affect the aesthetic outcome. CLINICAL RELEVANCE: In relation to the excellent outcomes found, the use of AM offers an alternative treatment procedure for RFFF defect covering.

Machine learning based prediction of perioperative blood loss in orthognathic surgery.

The aim of this study was to evaluate, if and with what accuracy perioperative blood loss can be calculated by a machine learning algorithm prior to orthognathic surgery. The investigators implemented a random forest algorithm to predict perioperative blood loss. 1472 patients who underwent orthognathic surgery from 01/2006 to 06/2017 at our institution were screened and 950 patients were included and separated 80%/20% in a training set - utilized to generate the prediction model - and a testing set - utilized to estimate the accuracy of the model. The outcome variable was the correlation between actual perioperative blood loss and predicted perioperative blood loss in the testing set. Other study variables were the difference of actual and predicted perioperative blood loss and important factors influencing perioperative blood loss using random forest feature importance. Descriptive and bivariate statistics were computed and the P value was set at 0.05. There was a statistically significant correlation between actual perioperative blood loss and predicted perioperative blood loss (p < 0.001). The mean difference was 7.4 ml with a standard deviation of 172.3 ml. The results of this study suggest that the application of a machine-learning algorithm allows a prediction of perioperative blood loss prior to orthognathic surgery.

Reduction of transfusion requirements in pediatric craniosynostosis surgery by a new local hemostatic agent.

BACKGROUND AND OBJECTIVES: Craniosynostosis surgery is often associated with severe perioperative bleeding especially due to venae emissariae, resulting in large transfusion amounts of packed red blood cells (PRBCs). Blood loss from venae emissariae is usually reduced by the usage of bone wax. SeraSeal is a new hemostatic agent which might help to reduce transfusion amounts if used additionally to bone wax. MATERIALS AND METHODS: This study was designed with a retrospective control group (23 children), treated only with bone wax and a consecutive prospective verum group (12 children) treated additionally with SeraSeal. All children solely suffered from non-syndromic craniosynostosis, and were all treated by the same surgeons. Primary outcome variable was the volume of PRBC transfused during surgery. RESULTS: The numbers of PRBC transfusion was reduced significantly during the intraoperative period in the SeraSeal group (-44.5%, p < 0.05) and also during the combination of the postoperative and intraoperative period (-59.3%, p < 0.05). CONCLUSION: Our analysis suggests that SeraSeal has a strong potential to reduce transfusion requirements in pediatric craniosynostosis surgery. However, we acknowledge that due to small numbers our trial can only be seen as hypothesis generating pilot study. We suggest that the effect of SeraSeal should be assessed prospectively in other studies.