Development of a testing device for external wrist bridging dynamic fixators used for distal radius fractures.

BACKGROUND: Stabilization of extra-articular distal radius fractures by wrist joint bridging (WB) dynamic fixation allows for early motion of the wrist, but relies on exact positioning of the device. In fact, physiological movement appeared to be compromised with even distinctly aberrant positioning of such device. To investigate this issue in more detail, we developed an in-vitro testing apparatus suitable for assessing the forces required for flexion and extension of the wrist. METHODS: The experimental set-up enables the transmission of the translational movement of the traverse of a universal testing machine into the main physiological movement (flexion and extension) of the wrist. An external WB dynamic fixator was assembled to an artificial saw bone wrist model prior and after performing a wedge-shaped osteotomy on the distal radius about 1.5 cm proximal to the joint line, i.e. generation of a fracture model. The functionality of the fixator was evaluated under either condition and the effect of misalignment of the external WB dynamic fixator was quantified by purposeful violation of the manufacture's instructions. Results were statistically analyzed using the generalized linear mixed model. FINDINGS: Significantly higher loading was noted as the degree of misalignment increased. The normalized force was significantly higher at a misalignment of 20° compared to 10° (10°: 4.13; 20°: 6.93, P < 0.001). INTERPRETATION: The proposed set-up turned out to allow highly reproducible and sensitive recording of the reaction forces during flexion and extension of the wrist and thus is feasible for the evaluation and comparison of different external WB devices.

Quality of Life after Desarda Technique for Inguinal Hernia Repair-A Comparative Retrospective Multicenter Study of 120 Patients.

Inguinal hernia repair, according to Desarda, is a pure tissue surgical technique using external oblique fascia to reinforce the posterior wall of the inguinal canal. This has provided an impetus for the rethinking of guideline adherence toward minimally invasive and mesh-based surgery of inguinal hernia. In this study, a retrospective analysis of this technique was conducted in two German hospitals. Between 6/2013 and 12/2020, 120 operations were performed. Analysis included patient characteristics, duration of operation, length of hospital stay, and perioperative complications. Data were used to achieve a matched-pair analysis comparing Desarda to laparoscopic transabdominal preperitoneal (TAPP) hernia repair. Propensity scores were calculated based on five preoperative variables, including sex, age, American Society of Anesthesiology classification, localization, and width of the inguinal hernia in order to achieve comparability. Additionally, we assessed pain level and quality of life (QoL) 12 months postoperatively. The focus of our study was a comparison of QoL to a reference population and TAPP cohort. The study population consisted of 106 male and 14 female patients, and the median age was 37.5 years. The median operation time was 50 min, and the median length of hospital stay was 2 days. At a follow-up of 17 months, the median recurrence rate was 0.8%, and two cases of chronic postoperative pain were recorded. Postoperative QoL does not significantly differ between Desarda and TAPP. In contrast, Desarda patients had a significantly higher QoL compared with the reference population. In summary, Desarda's procedure is a good option as a pure tissue method for inguinal hernia repair.

More than 30 Years of POSSUM: Are Scoring Systems Still Relevant Today for Colorectal Surgery?

BACKGROUND: The Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) weights the patient's individual health status and the extent of the surgical procedure to estimate the probability of postoperative complications and death of general surgery patients. The variations Portsmouth-POSSUM (P-POSSUM) and colorectal POSSUM (CR-POSSUM) were developed for estimating mortality in patients with low perioperative risk and for patients with colorectal carcinoma, respectively. The aim of the present study was to evaluate the significance of POSSUM, P-POSSUM, and CR-POSSUM in two independent colorectal cancer cohorts undergoing surgery, with an emphasis on laparoscopic procedures. METHODS: For each patient, an individual physiological score (PS) and operative severity score (OS) was attributed to calculate the predicted morbidity and mortality, respectively. Logistic regression analysis was used to evaluate the possible correlation between the subscores and the probability of postoperative complications and mortality. RESULTS: The POSSUM equation significantly overpredicted postoperative morbidity, and all three scoring systems considerably overpredicted in-hospital mortality. However, the POSSUM score identified patients at risk of anastomotic leakage, sepsis, and the need for reoperation. Logistic regression analysis demonstrated a strong correlation between the subscores and the probability of postoperative complications and mortality, respectively. CONCLUSION: Our results suggest that the three scoring systems are too imprecise for the estimation of perioperative complications and mortality of patients undergoing colorectal surgery in the present day. Since the subscores proved valid, a revision of the scoring systems could increase their reliability in the clinical setting.

Assessment of Quality of Life after Endovascular and Open Abdominal Aortic Aneurysm Repair: A Retrospective Single-Center Study.

Postoperative quality of life is an important outcome parameter after treatment of abdominal aortic aneurysms. The aim of this retrospective single-center study was to assess and compare the health-related quality of life (HRQoL) of patients after open repair (OR) or endovascular treatment (EVAR), and furthermore to investigate the effect of incisional hernia (IH) formation on HRQoL. Patients who underwent OR or EVAR for treatment of an abdominal aortic aneurysm between 2008 and 2016 at a University Medical Center were included. HRQoL was assessed using the SF-36 questionnaire. The incidence of IH was recorded from patient files and by telephone contact. SF-36 scores of 83 patients (OR: n = 36; EVAR: n = 47) were obtained. The mean follow-up period was 7.1 years. When comparing HRQoL between OR and EVAR, patients in both groups scored higher in one of the eight categories of the SF36 questionnaires. The incidence of IH after OR was 30.6%. In patients with postoperative IH, HRQoL was significantly reduced in the dimensions "physical functioning", "role physical" and "role emotional" of the SF-36. Based on this data, it can be concluded that neither OR nor EVAR supply a significant advantage regarding HRQoL. In contrast, the occurrence of IH has a relevant impact on the HRQoL of patients after OR.

Evaluation of Hyperspectral Imaging for Follow-Up Assessment after Revascularization in Peripheral Artery Disease.

BACKGROUND: Assessment of tissue oxygenation is an important aspect of detection and monitoring of patients with peripheral artery disease (PAD). Hyperspectral imaging (HSI) is a non-contact technology for assessing microcirculatory function by quantifying tissue oxygen saturation (StO2). This study investigated whether HSI can be used to monitor skin oxygenation in patients with PAD after appropriate treatment of the lower extremities. METHODS: For this purpose, 37 patients with PAD were studied by means of ankle-brachial index (ABI) and HSI before and after surgical or endovascular therapy. Thereby, the oxygenation parameter StO2 and near infrared (NIR) perfusion index were quantified in seven angiosomes on the diseased lower leg and foot. In addition, the effects of skin temperature and physical activity on StO2 and the NIR perfusion index and the respective inter-operator variability of these parameters were investigated in 25 healthy volunteers. RESULTS: In all patients, the ABI significantly increased after surgical and endovascular therapy. In parallel, HSI revealed significant changes in both StO2 and NIR perfusion index in almost all studied angiosomes depending on the performed treatment. The increase in tissue oxygenation saturation was especially pronounced after surgical treatment. Neither heat nor cold, nor physical activity, nor repeated assessments of HSI parameters by independent investigators significantly affected the results on StO2 and the NIR perfusion index. CONCLUSIONS: Tissue oxygen saturation data obtained with HSI are robust to external confounders, such as temperature and physical activity, and do not show inter-operator variability; therefore, can be used as an additional technique to established methods, such as the ABI, to monitor peripheral perfusion in patients with PAD.

Acute Mesenteric Ischemia: Preexisting Comorbidity Determines Short-Term Outcome and Quality of Life in Long-Term Survivors.

Introduction: Acute mesenteric ischemia (AMI), either arterial or venous, is still a devastating disease with poor prognosis. It is unknown, whether AMI is associated with impaired quality of life (QoL) in long-term survivors. Material and Methods: This retrospective analysis includes 64 patients with occlusive arterial or venous mesenteric ischemia treated operatively between 2008 and 2016 at the University Medical Center Rostock. Short-term outcome with focus on comorbidities was measured by the Charlson comorbidity index (CCI) an instrument that operationally measures comorbidity based on 17 clinical parameters including age. Operative outcome in view of enterostomy placement and long-term outcome measured as QoL by the EQ-5D in the long-term survivors were evaluated. The EQ-5D is a standardized, self-reported five-dimension QoL questionnaire built to provide a simple and generic measure of health. Results: Thirty-day mortality was 60.9%, and in-hospital mortality was 70.3% (n = 45). No patient was discharged with a stoma. Patients with a primary anastomosis after the initial operation for AMI had a high leak rate of 27% (4/15 patients) compared to no dehiscence in the group of patients who had secondary anastomosis during second or third laparotomy. The long-term survivors had significantly lower CCI compared to the 45 nonsurvivors (median 4 [3, 4, 5, 6] vs. 6 [4, 5, 6, 7]). All long-term survivors had QoL assessment. QoL score was significantly impaired compared to an age- and sex-matched reference population. This impairment was not due to disease-specific sequelae such as presence of stool deviation or intestinal failure but due to preexisting risk factors as shown by an inverse relation between the CCI and QoL score. Conclusion: Herein, we show for the first time that long-term QoL in patients with AMI is impaired but this impairment is not due to disease-specific aspects but rather general risk factors underlying the presence of a higher level of comorbidities at the time of AMI.

Use of incisional preventive negative pressure wound therapy in open incisional hernia repair: Who benefits?

Complex surgery of abdominal wall hernia continues to bear the major concern of wound healing disorders. Technical modifications have not been able to sufficiently prevent wound healing impairments or infections, even in clean elective cases, especially when dealing with large-scale hernia defects. Incisional negative pressure wound therapy (iNPWT) in its intentional use as a preventive tool has recently found its way from theoretical and experimental advantages to the clinical routine. Different indications have been defined but evidence is lacking. We performed a retrospective analysis (1/2014-5/2019) of all ventral hernia repairs (n = 386) done in our institution as open sublay mesh reinforcement, partially requiring component separation (CS), receiving iNPWT in selected cases based on single surgeon experience. Pre- and perioperative data included patient and hernia characteristics as well as the employed mesh sizes. Postoperative follow-up (median 38.5 months [interquartile range: 23.4, 53.3]) extended beyond patient dismissal and included the rate of re-admission due to wound healing disorders. The primary outcome was the incidence of surgical site occurrences (SSO). Secondary endpoints included wound-related readmissions, reoperations and recurrences. Patients were matched based on propensity scores in a 1:1 ratio. Propensity scores were calculated based on five preoperative variables, including sex, body-mass-index, American Society of Anesthesiology classification, recurrent hernia repair and operation technique, to identify significant parameters. The rate of SSO was 12% (n = 46) for all operated cases, and the rate of surgical site infection (SSI) was 8.8% (n = 34). In the subgroup of CS (n = 40), the rate increased to 15% (n = 6). The usage of iNPWT (n = 54) led to an in-hospital SSO rate of 14.8% (n = 8) but increased to 33.3% (n = 18) when including the re-admission rate. The SSI rate for the iNPWT cohort was 14.8% (n = 8) with a consecutive need for reoperation (Clavien-Dindo IIIb) in 87.5% (n = 7). In the matched-pair analysis, the hernia-size and mesh-size were the main risk factors for SSO. The use of iNPWT significantly reduced this statistical effect (p = 0.405). In a large and representative patient cohort, we were able to demonstrate that the advantage of iNPWT used after complex abdominal wall repair does not come first hand. Especially in the follow-up, we found a relevant increase in wound healing problems after dismissal. To proof the benefit of iNPWT in these heterogeneous patients, we could identify hernia size and mesh size as individual risk factors that were nihilated by the use of iNPWT. We found it to be favourable to use iNPWT when mesh-size exceeded 450 cm2 .

Quality of Life after Complex Abdominal Wall Reconstruction.

BACKGROUND: Component separation (CS) for tension-free approximation of fascial edges is the established technique for the repair of large ventral hernias mostly regarding midline defects. Recent studies suggest lower complication rates following a modified version of this technique using a partially endoscopic-assisted approach, whereas little is known about the quality of life (QoL) in the long-term evaluation of these patients. METHODS: A retrospective study and analysis of patients undergoing hernia repair using an open CS (OCS) and endoscopically assisted CS (ECS) technique, respectively, from 2011 to 2016 at the Rostock University Medical Center. Patients underwent a mesh-based sublay reinforcement following a distinct CS with closure of the linea alba. Patient characteristics, technical details, and short-term postoperative outcomes were determined by a physician chart review. A health-related QoL survey (EQ-5D) including a pain assessment was evaluated at a median of 19.5 months postoperatively. RESULTS: Thirty-five patients had a CS: 25 OCS and 10 ECS. Perioperative variables were comparable except for the median defect size (169 cm2 OCS vs. 86 cm2 ECS; p < 0.05) and maximum width of hernia (25 vs. 13 cm). Hospitalization lasted 16.6 days in the OCS group and 7.9 days in the endoscopic group (p = 0.04). Wound complications occurred in 24% of OCS and 10% of ECS patients. CONCLUSIONS: Patients in the ECS group had a shorter hospital stay and less minor and major wound complications. These advantages led to a faster recovery directly affecting the QoL in the ECS group. This effect diminishes in the long-term follow-up with a positive trend towards the OCS technique.

Integrated Biobanking and Tumor Model Establishment of Human Colorectal Carcinoma Provides Excellent Tools for Preclinical Research.

Over the time period from 2006 to 2017, consecutive patients operated on at the University Medical Center Rostock participated in the comprehensive biobanking and tumor-modelling approach known as the HROC collection. Samples were collected using strict standard operating procedures including blood (serum and lymphocytes), tumor tissue (vital and snap frozen), and adjacent normal epithelium. Patient and tumor data including classification, molecular type, clinical outcome, and results of the model establishment are the essential pillars. Overall, 149 patient-derived xenografts with 34 primary and 35 secondary cell lines were successfully established and encompass all colorectal carcinoma anatomic sites, grading and staging types, and molecular classes. The HROC collection represents one of the largest model assortments from consecutive clinical colorectal carcinoma (CRC) cases worldwide. Statistical analysis identified a variety of clinicopathological and molecular factors associated with model success in univariate analysis. Several of them not identified before include localization, mutational status of K-Ras and B-Raf, MSI-status, and grading and staging parameters. In a multivariate analysis model, success solely correlated positively with the nodal status N1 and mutations in the genes K-Ras and B-Raf. These results imply that generating CRC tumor models on the individual patient level is worth considering especially for advanced tumor cases with a dismal prognosis.

Evaluation of peripheral artery disease with the TIVITA® Tissue hyperspectral imaging camera system.

BACKGROUND: Objective, reliable and easy screening for peripheral artery disease (PAD) is essential to confirm the diagnosis and initiate the respective treatment. Therefore, a new non-invasive hyperspectral camera (TIVITA® Tissue) was tested in patients with and without PAD. OBJECTIVE: It was hypothesized that the oxygenation parameters of the TIVITA® Tissue correlate to established modalities for detection of PAD and allow differentiation between individuals with and without PAD. METHODS: Evaluation of tissue oxygenation was performed in the angiosome of the medial plantar artery in 25 healthy young people and in 24 patients with and 25 patients without PAD in comparable age. Thereby, superficial oxygenation (StO2) and near-infrared (NIR) perfusion index were measured with the TIVITA® Tissue. Additionally, the ankle-brachial-index (ABI), the complaint free walking distance and the vascular quality of life were assessed and demographic data were obtained from all participants. RESULTS: TIVITA® Tissue analysis revealed significantly reduced StO2 and NIR perfusion index in PAD compared to healthy young participants and patients without PAD. StO2 and NIR perfusion index positively correlated with ABI, the complaint free walking distance and the vascular quality of life score. CONCLUSIONS: In summary, this new hyperspectral imaging camera bears great potential for PAD screening as well as for follow up.

Multistate modelling extended by behavioural rules: An application to migration.

We propose to extend demographic multistate models by adding a behavioural element: behavioural rules explain intentions and thus transitions. Our framework is inspired by the Theory of Planned Behaviour. We exemplify our approach with a model of migration from Senegal to France. Model parameters are determined using empirical data where available. Parameters for which no empirical correspondence exists are determined by calibration. Age- and period-specific migration rates are used for model validation. Our approach adds to the toolkit of demographic projection by allowing for shocks and social influence, which alter behaviour in non-linear ways, while sticking to the general framework of multistate modelling. Our simulations yield that higher income growth in Senegal leads to higher emigration rates in the medium term, while a decrease in fertility yields lower emigration rates.

Emigration Rates From Sample Surveys: An Application to Senegal.

What is the emigration rate of a country, and how reliable is that figure? Answering these questions is not at all straightforward. Most data on international migration are census data on foreign-born population. These migrant stock data describe the immigrant population in destination countries but offer limited information on the rate at which people leave their country of origin. The emigration rate depends on the number leaving in a given period and the population at risk of leaving, weighted by the duration at risk. Emigration surveys provide a useful data source for estimating emigration rates, provided that the estimation method accounts for sample design. In this study, emigration rates and confidence intervals are estimated from a sample survey of households in the Dakar region in Senegal, which was part of the Migration between Africa and Europe survey. The sample was a stratified two-stage sample with oversampling of households with members abroad or return migrants. A combination of methods of survival analysis (time-to-event data) and replication variance estimation (bootstrapping) yields emigration rates and design-consistent confidence intervals that are representative for the study population.