Assessing the outcome of orthognathic surgery by three-dimensional soft tissue analysis

Studies of orthognathic surgery often focus on pre-surgical versus post-surgical changes in facial shape. In contrast, this study provides an innovative comparison between post-surgical and control shape. Forty orthognathic surgery patients were included, who underwent three different types of surgical correction: Le Fort I maxillary advancement, bilateral sagittal split mandibular advancement, and bimaxillary advancement surgery. Control facial images were captured from volunteers from local communities in Glasgow, with patterns of age, sex, and ethnic background that matched those of the surgical patients. Facial models were fitted and Procrustes registration and principal components analysis used to allow quantitative analysis, including the comparison of group mean shape and mean asymmetry. The primary characteristic of the difference in shape was found to be residual mandibular prognathism in the group of female patients who underwent Le Fort I maxillary advancement. Individual cases were assessed against this type of shape difference, using a quantitative scale to aid clinical audit. Analysis of the combined surgical groups provided strong evidence that surgery reduces asymmetry in some parts of the face such as the upper lip region. No evidence was found that mean asymmetry in post-surgical patients is greater than that in controls.

Abstract 351: National Rates of Venous Thromboembolism in Patient with STEMI: Results from the National Inpatient Sample 2003-2013

Background: There is a growing body of evidence against the use of triple therapy (anticoagulation and dual antiplatelet) among patients with acute coronary syndrome. Venous thromboembolism (VTE) is another potential indication for triple therapy, but the magnitude of such problem is unknown. Therefore, we aimed to determine the trends of annual rate of immediate VTE occurrence in patients with ST-segment elevation myocardial infarction (STEMI) and measure its impact.

Methods: We queried the 2003-2013 Nationwide Inpatient Sample to identify adults with primary diagnosis of STEMI using ICD-9-CM codes. VTE, including limb vein thrombosis and pulmonary embolism, was allocated when present among the secondary discharge diagnosis. Demographics and inpatient outcomes were compared in the VTE and non-VTE group.

Results: From 2,495,757 hospitalizations for STEMI, 15,471 (0.6%) also experienced VTE. The group who experienced VTE was older (mean age: 68.44 vs 64.81, p<0.01) and had higher proportions of black patients (10.6% vs 7.7%, p<0.001) and females (42.1% vs 35%, p<0.001) compared to the non-VTE group. There was an increasing trend in the annual rate of VTE during the study period (2003: 0.3% vs 2013: 0.9%, p < 0.01). Patients with VTE had a prolonged hospitalization (12.8 vs 4.63 days, p <0.01), higher risk of gastrointestinal bleeding (OR:1.65; 95% CI 1.54-1.76, p<0.01) and intracranial hemorrhage(OR:1.52, 95% CI:1.23-1.87, P<0.01), needed more blood transfusions (OR:1.74; 95% CI:1.66-1.82, p<0.01) and had increased mortality (OR:1.53, 95%CI:1.46-1.6, p<0.01).

Conclusion: There is an increasing annual rate in immediate VTE occurrence in patients with STEMI. VTE is associated with more bleeding complications, longer hospital stay, and higher mortality. It is plausible that individualized or more aggressive protocols of VTE prophylaxis are needed in this population.

Abstract 715: Peripheral Artery Disease in Patients with End Stage Renal Disease: Nationwide Trends in Management and Outcomes

Background: Patients with end stage renal disease (ESRD) are at high risk for peripheral artery disease (PAD). We sought to determine the national prevalence of PAD, trends in management and outcomes among this high risk population.

Methods: We queried the 2003-2014 National Inpatient Sample databases to identify PAD related admissions (claudication and critical limb ischemia) among patients with ESRD using ICD-9 codes. Temporal trends in treatment options, and in-hospital mortality were analyzed. Multivariate logistic regression was used to assess predictors of major amputation.

Results: Among 9 million ESRD patient admissions, 357,949 (3.9%) had PAD related diagnosis. Patients were mainly white (39%), men (58%), with mean age of 65.6 years. The prevalence of PAD slightly decreased from 4.3% in 2003 to 3.9% in 2014 (P trend < 0.001). Utilization of percutaneous transluminal angioplasty (PTA) increased by 142% (10.6% to 25.7%), whereas, open bypass use decreased by 51% (14.1% to 6.9%) during the study period (P trend < 0.001). Moreover, the total number of major amputations was 65,669. There was a notable decline in its usage from 25.9% to 15.3% (adjusted odds ratio [OR] per year: 0.96; 95% confidence interval: 0.95-0.98, P<0.001). Revascularization appeared to reduce the risk of amputation (OR 0.49, P<0.001). On the contrary, hypertension (OR 2.5, P<0.001), heart failure (OR 1.5, P<0.001), and black race (OR 1.5, P<0.001) were independent predictors of amputation. Overall in-hospital mortality rate was 6.3%, with no statistically significant trend throughout the years.

Conclusion: PAD is a common disease in ESRD patients. Among therapeutic options, a significant increase in less invasive endovascular revascularization methods and a decline in open bypass surgeries were noted. Despite the significant drop in amputation rates, racial disparities persist, with black patients having higher odds of major amputation.

Abstract 726: Intermittent Pneumatic Compression during Hemodialysis to improve Quality of Life in Patients with Peripheral Artery Disease and End Stage Renal Disease

Peripheral artery disease (PAD) is a prevalent global problem with increased mortality. Affects about one in four patients with end stage renal disease (ESRD). Intermittent pneumatic compression (IPC) has shown improvement of lower extremity hemodynamics and symptoms and may be implemented during hemodialysis (HD).

We designed a trial to test the utility of IPC in the ESRD population by assessing improvement in quality of life (QOL) and functional limitation from PAD-related symptoms. We aim to present our design and initial results.

Methods: This is a prospective single cohort study for paired analysis undergoing recruitment of outpatients at the HD unit of John H. Stroger, Jr. Hospital of Cook County. A sample size of 78 yields a power of 80% and alpha of 0.05, assuming an average peak walking time of five minutes and 25% improvement after supervised exercise. PAD is confirmed by ankle-brachial index (ABI) and demographics collected. A baseline Six-minute Walk Test (6MWT), Peripheral Artery Questionnaire (PAQ) and Walking Impairment Questionnaire (WIQ) are administered and will be compared with their performance post intervention. The IPC device (Bio Arterial Plus) will be used for intervention during each HD for two months average. We present continuous variables as mean±SD and categorical variables as percentage.

Results: From 10 recruited patients in the first month, 60% are men, age 54.6±13.1 years, the majority Hispanic (80%). 70% of ABI were abnormal, all due to non-compressible PAD (1.44±0.20). All patients have HTN, 50% diabetes, 20% hyperlipidemia, 10% had a stroke and 10% revascularization for PAD. At baseline 6MWT, distance walked was 357.7±59.5 m, with 600±52.5 total steps and fatigue as main symptom (30%) and no typical claudication. QOL questionnaires showed WIQ walking distance 68.58±18.04, WIQ walking speed 72.5±26.36, and WIQ stair climbing 50.04±30.04 points; PAQ physical limitation 61±21.4, PAQ symptoms 62.79±18.7, PAQ satisfaction 68.67±27.9, PAQ quality of life 64±13.04, and PAQ social limitation 70±23.13 points.

Conclusion: Non-compressible PAD is prevalent in ESRD, and QOL seems significantly compromised from it. Our trial will provide insight of an alternative therapy, and optimize the time in HD even further.

Abstract 352: National Trends in Cancer-Associated Thrombosis Hospitalizations among Patients with Pancreatic, Gastric and Lung Primary: Results from Nationwide Inpatient Sample Database 2009-2014

Introduction: Venous thromboembolism ( VTE ) is a leading cause of morbidity and mortality in cancer; and its occurrence leads to an increased number of hospitalizations. Therefore, we aimed to determine the trends in the annual rate of cancer-associated thrombosis ( CAT ) hospitalizations and measure its impact in patients with highly thrombogenic tumor types, such as pancreas, stomach and lung.

Methods: We queried the 2009-2014 Nationwide Inpatient Sample database to identify adults with gastric, pancreatic or lung cancer. Hospitalizations in which VTE was among the top-three discharge diagnoses, were considered as CAT admissions. In-hospital outcomes of patients with VTE were compared to those without VTE. Using SPSS, version 24, we conducted a linear regression analysis for trend and binary logistic regression analysis to obtain adjusted odds ratios ( OR )

Results: From 3 million admissions, 149.577 (4.9%) were related to VTE. The patients were mainly white (68.9%) men (53.2%) with a median age of 69 (IQR:17) years; and the predominant tumor type was lung cancer (73.4%). Although the rate of CAT admissions remained steady during the study period (2009: 5.0% vs 2014: 4.9%, p <0.01), the inpatient mortality was higher among patients admitted with CAT (10.2% vs 9.3%, OR:1.11, CI: 1.08 - 1.13, p < 0.01). The negative effect of VTE on inpatient mortality persisted after adjusting for tumor type, metastatic disease and demographics (OR:1.11, CI: 1.08 - 1.13, p < 0.01). The median length of stay was 5 days in both groups (p<0.01), but the cost was significantly higher among those admitted with CAT (USD33,468 vs USD30,452, p <0.01). Figure 1 summarizes demographics ( A ) and trends ( B )

Conclusion: CAT admissions in patients with stomach, pancreas and lung cancer are associated with a higher inpatient mortality and its management is costly. Conceivably, risk stratification based on early mortality may assist in therapy and resources selection to improve outcomes and cost allocation.

Abstract 247: Is Oxygen Therapy Beneficial in Acute Myocardial Infarction? A Meta-Analysis

Background: Supplemental oxygen (O2) is beneficial in patients with acute myocardial infarction (AMI) who have hypoxemia. However in patients who have suspected AMI without hypoxemia, the benefit of O2 remains uncertain. We conducted a meta-analysis, including the recent landmark trials, to establish the efficacy and safety of O2 in AMI.

Methods: We searched Medline, Embase, and Ovid SP databases for randomized clinical trials that compared O2 with room air in suspected AMI without hypoxemia. Hypoxemia was defined as O2 saturation of <90%. The primary endpoint was all-cause mortality. Data were pooled by the random effects model and I2 was used to assess for the heterogeneity.

Results: A total of 6 studies including 8193 participants were included in the final analysis. On pooled analysis, there was no significant difference between the two arms in 30-day all-cause mortality (OR=1.10 [0.67, 1.80]; p=0.70), cardiogenic shock (OR=0.75 [0.49, 1.16]; p=0.19), recurrent myocardial infarction (OR=1.24 [0.46, 3.34]; p=0.67) and left ventricular ejection fraction (SMD= -1.95 [-4.76, 0.85]; p=0.17).

Conclusion: Contrary to the routine clinical practice, our analysis shows that O2 administration does not provide any benefit in AMI patients who have normal oxygen saturation. It is reasonable to reserve O2 only for patients with AMI and hypoxemia.

Assessment of facial asymmetry before and after the surgical repair of cleft lip in unilateral cleft lip and palate cases

This study was performed to assess facial asymmetry in patients with unilateral cleft lip and palate (UCLP) before and after primary lip repair. Three-dimensional facial images of 30 UCLP cases (mean age 3.7±0.8months) captured 1-2days before surgery and 4 months after surgery using stereophotogrammetry were analysed. A generic mesh - a mathematical facial mask consisting of thousands of points (vertices) - was conformed on the three-dimensional images. Average preoperative and postoperative conformed facial meshes were obtained and mirrored by reflecting on the lateral plane. Facial asymmetry was assessed by measuring the distances between the corresponding vertices of the superimposed facial meshes. Asymmetries were further examined in three directions: horizontal, vertical, and anteroposterior. Preoperatively, the philtrum and bridge of the nose were deviated towards the non-cleft side. The maximum vertical asymmetry was at the upper lip. The greatest anteroposterior asymmetry was at the alar base and in the paranasal area. The overall facial asymmetry improved markedly after surgery. Residual anteroposterior asymmetry was noted at the alar base, upper lip, and cheek on the cleft slide. In conclusion, dense correspondence analysis provided an insight into the anatomical reasons for the residual dysmorphology following the surgical repair of cleft lip for future surgical consideration.

The accuracy of three-dimensional prediction of soft tissue changes following the surgical correction of facial asymmetry: An innovative concept

The accuracy of three-dimensional (3D) predictions of soft tissue changes in the surgical correction of facial asymmetry was evaluated in this study. Preoperative (T1) and 6-12-month postoperative (T2) cone beam computed tomography scans of 13 patients were studied. All patients underwent surgical correction of facial asymmetry as part of a multidisciplinary treatment protocol. The magnitude of the surgical movement was measured; virtual surgery was performed on the preoperative scans using Maxilim software. The predicted soft tissue changes were compared to the actual postoperative appearance (T2). Mean (signed) distances and mean (absolute) distances between the predicted and actual 3D surface meshes for each region were calculated. The one-sample t-test was applied to test the alternative hypothesis that the mean absolute distances had a value of <2.0mm. A novel directional analysis was applied to analyse the accuracy of the prediction of soft tissue changes. The results showed that the distances between the predicted and actual postoperative soft tissue changes were less than 2.0mm in all regions. The predicted facial morphology was narrower than the actual surgical changes in the cheek regions. 3D soft tissue prediction using Maxilim software in patients undergoing the correction of facial asymmetry is clinically acceptable.

A Review of Water-Resistant Hemicellulose-Based Materials: Processing and Applications

Hemicelluloses, due to their hydrophilic nature, may tend to be overlooked as a component in water-resistant product applications. However, their domains of use can be greatly expanded by chemical derivatization. Research in which hydrophobic derivatives of hemicelluloses or combinations of hemicelluloses with hydrophobic materials are used with to prepare films and composites is considered herein. Isolation methods that have been used to separate hemicellulose from biomass are also reviewed. Finally, the most useful pathways to change the hydrophilic character of hemicelluloses to hydrophobic are reviewed. In this way, the water resistance can be increased and applications of targeted water-resistant hemicellulose developed. Several applications of these materials are discussed.

Neurosensory deficit following mandibular sagittal split osteotomy: A comparative study between positional screws and miniplates fixation

This retrospective study compared the incidence of long-term inferior alveolar nerve injury for positional screws and miniplate fixation of bilateral sagittal split osteotomies carried out in 2 hospitals in Scotland. The study involved a mixture of mandibular setback and advancement surgery. The outcome of neurosensory deficit (NSD) was solely based on subjective assessment by the surgeons and patients' reported alteration in sensation. Numbness, tingling and any alterations in sensation beyond 6 months were considered long-term inferior alveolar nerve injury. This study was conducted on 28 sagittal split osteotomies (group 1) which were fixed with three upper border fixation screws and 36 sagittal split osteotomies (group 2) which were fixed with upper border sliding plate. The reported and documented neurosensory deficits were analysed. The difference in the number of cases of long-term inferior alveolar nerve injury between the 2 methods was 10.3%; the 95% confidence interval for the difference was [-2.94 to 23.5], p = 0.1612. Upper border plate was associated with more long-term NSD but there is insufficient evidence to prove that one method was more superior to the other. The need for a prospective randomized trial was highlighted.

State-of-the-art three-dimensional analysis of soft tissue changes following Le Fort I maxillary advancement

We describe the comprehensive 3-dimensional analysis of facial changes after Le Fort I osteotomy and introduce a new tool for anthropometric analysis of the face. We studied the cone-beam computed tomograms of 33 patients taken one month before and 6-12 months after Le Fort I maxillary advancement with or without posterior vertical impaction. Use of a generic facial mesh for dense correspondence analysis of changes in the soft tissue showed a mean (SD) anteroposterior advancement of the maxilla of 5.9 (1.7) mm, and mean (SD) minimal anterior and posterior vertical maxillary impaction of 0.1 (1.7) mm and 0.6 (1.45) mm, respectively. It also showed distinctive forward and marked lateral expansion around the upper lip and nose, and pronounced upward movement of the alar curvature and columella. The nose was widened and the nostrils advanced. There was minimal forward change at the base of the nose (subnasale and alar base) but a noticeable upward movement at the nasal tip. Changes at the cheeks were minimal. Analysis showed widening of the midface and upper lip which, to our knowledge, has not been reported before. The nostrils were compressed and widened, and the lower lip shortened. Changes at the chin and lower lip were secondary to the limited maxillary impaction.

Efficacy of three-dimensional visualization in mobile apps for patient education regarding orthognathic surgery

'Sur-face' is an interactive mobile app illustrating different orthognathic surgeries and their potential complications. This study aimed to evaluate the efficacy of Sur-face by comparing two methods of delivering patient information on orthognathic surgeries and their related potential complications: a mobile app with interactive three-dimensional (3D) animations and a voice recording containing verbal instructions only. For each method, the participants' acquired knowledge was assessed using a custom-designed questionnaire. Participants in the 'app' group performed significantly better (P<0.0034) than those in the 'voice' group and retained more knowledge, suggesting that interactive visualizations play a key role in improving understanding of the orthognathic surgical procedure and its associated complications. This study emphasizes the impact of 3D visualizations in delivering information regarding orthognathic surgery and highlights the advantage of delivering validated patient information through mobile apps.

[Landmark-based statistical procrustes analysis in the examination of breast shape and symmetry]

AIM

The aim of this presentation is the explanation of a mathematical analysis of a landmark-based procrustes calculation. The various components of breast symmetry and their impact on breast reconstruction have been examined.

METHOD

In an objective breast shape analysis asymmetries are quantified as a measure of the difference between a 3D landmark configuration of a breast and its mirror image. 10 landmarks, 4 on each side and 2 for a definition of the midline were defined. For each landmark the 3D coordinates were calculated statistically with the help of the software Programme R. Over a midline from the jugulum to the manubrium sterni, a mirror image of the breast was constructed. The data for the breast to be reconstructed and the non-operated breast from 44 patients were investigated. The statistical differences of the Procrustes analysis were used for an asymmetry score and the proportions of the individual components were calculated. These included size, location and orientation of the breast as well as the individual inherent morphological surface form data of the breast.

RESULTS

All 44 patients exhibited breast asymmetries and the mean asymmetry score amounted to 0.52. A calculation of the proportions of the individual components making up the asymmetry score revealed that morphological surface data made the largest contribution to the asymmetry score, closely followed by location, i. e., positioning of the breast on the thoracic wall. In contrast, the size of the breast and its orientation were of lesser relevance.

CONCLUSION

When considering breast symmetry in plastic surgery, the form plays a more important role than the size as objectively calculated by the statistical procrustes analysis. Almost equally important as the form is the positioning of the breast on the thoracic wall which contributes significantly more to total breast symmetry than axial displacements.

[Obstructive sleep apnea syndrome in the elderly]

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a common disease in the general population. However, original works on the SAHS in the elderly are few and their results are discordant. Studies show an increased prevalence of OSAHS with age, and despite this high prevalence, it remains under-diagnosed due to lack of knowledge of geriatric features of this disease and the frequency of comorbidities that may worsen as a result of nocturnal breathing problems but can also mask the symptoms necessary for positive diagnosis. The functional symptoms are dominated by neurological signs such as daytime hypersomnia and cognitive impairment often reported by those around the patient. The treatment is based mainly on continuous positive airway pressure which tolerance in elderly patients suffering from sleep apnea is similar to that of younger patients. Mandibular implants can be discussed depending on the severity of the condition. Surgical treatment is not indicated because of the increased frequency of complications.