Energy Structure and Luminescence of CeF3 Crystals

The results of the calculation of the energy band structure and luminescent research of CeF₃ crystals are presented. The existence of two 5d1 and 5d2 subbands of the conduction band genetically derived from 5d states of Ce³⁺ ions with different effective electron masses of 4.9 m_e and 0.9 m_e, respectively, is revealed. The large electron effective mass in the 5d1 subband facilitates the localization of electronic excitations forming the 4f-5d cerium Frenkel self-trapped excitons responsible for the CeF₃ luminescence. The structure of the excitation spectra of the exciton luminescence peaked at 290 nm, and the defect luminescence at 340 nm confirms the aforementioned calculated features of the conduction band of CeF₃ crystals. The peculiarities of the excitation spectra of the luminescence of CaF₂:Ce crystals dependent on the cerium concentration are considered with respect to the phase formation possibility of CeF₃.     

Laparoscopic versus open distal pancreatectomy—a propensity score-matched analysis from the German StuDoQ|Pancreas registry

Purpose

The aim of this study was to assess intraoperative, postoperative, and oncologic outcome in patients undergoing laparoscopic distal pancreatectomy (LDP) versus open distal pancreatectomy (ODP) for benign and malignant lesions of the pancreas.

Methods

Data from patients undergoing distal pancreatic resection were extracted from the StuDoQ|Pancreas registry of the German Society for General and Visceral Surgery. After propensity score case matching, groups of LDP and ODP were compared regarding demography, comorbidities, operative details, histopathology, and perioperative outcome.

Results

At the time of data extraction, the StuDoQ|Pancreas registry included over 3000 pancreatic resections from over 50 surgical departments in Germany. Data from 353 patients undergoing ODP (n = 254) or LDP (n = 99) from September 2013 to February 2016 at 29 institutions were included in the analysis. Baseline data showed a strong selection bias in LDP patients, which disappeared after 1:1 propensity score matching. A comparison of the matched groups disclosed a significantly longer operation time, higher rate of spleen preservation, more grade A pancreatic fistula, shorter hospital stay, and increased readmissions for LDP. In the small group of patients operated for pancreatic cancer, a lower lymph node yield with a lower lymph node ratio was apparent in LDP.

Conclusions

LDP needed more time but potential advantages include increased spleen preservation and shorter hospital stay, as well as a trend for less transfusion, ventilation, and mortality. LDP for pancreatic cancer was performed rarely and will need critical evaluation in the future. Data from a prospective randomized registry trial is needed to confirm these results.

     

Postoperative Ulnar Neuropathy is not Necessarily Iatrogenic: a Prospective Study on Dynamic Ulnar Nerve Dislocation at the Elbow

Background

Patients who undergo surgery may develop ulnar neuropathy. Although the mechanism of ulnar neuropathy is still not clear, ulnar neuropathies are common causes of successful lawsuits against surgeons. Recently, the concept developed that endogenous patient factors can lead to postoperative peripheral neuropathies. We hypothesize that dynamic ulnar nerve dislocation at the elbow (DUNDE) may be a predisposing factor for ulnar irritation (i.e. neuropathy) in normal subjects.

Methods

In a prospective investigation, patients aged 20 years and older presenting in our emergency department were asked to participate. Three physicians examined both elbows of subjects included in our study for evidence of DUNDE (through clinical and sonographic examination) and for clinical symptoms related to ulnar neuropathy.

Results

Dynamic ulnar nerve dislocation was observed in 29.3 % of examined subjects. No significant difference in its occurrence was observed in relation to gender or dominant side. Physical examination with provocation tests demonstrated significantly more positive Tinel tests and spontaneous signs of neuropathy in patients with dynamic dislocating ulnar nerves (14.7 vs. 1.1 %).

Conclusion

Dynamic ulnar nerve dislocation may be linked to ulnar nerve irritability (i.e. ulnar neuropathy) in normal subjects without history of trauma, surgical procedure, or anesthesia. Considering the high incidence of this variant in the general population, our study supports previous investigations suggesting that many postoperative ulnar nerve deficits are traceable to chronic patient conditions. Our study suggests that dynamic ulnar nerve dislocation is a predisposing factor in the development of ulnar neuropathy in the postoperative period.

Notes

(1) neuropathy should be viewed as a broad definition as signs of nerve irritation/inflammation, and independently of the pathophysiology and etiology; (2) because no specific term exists in the international anatomic nomenclature (Nomina Anatomica) to designate this variant, several synonyms have been used in the literature, leading to confusion and misleading conclusions concerning its traumatic etiologies and their consequences: (a) recurrent or habitual ulnar nerve luxation (or subluxation) [1–3]; (b) recurrent or habitual ulnar nerve dislocation [4–7]; (c) ulnar nerve instability [8]; (d) laxity of the ulnar nerve [9]; and (e) ulnar nerve hypermobility [10].     

Prognostic relevance of preoperative bilirubin-adjusted serum carbohydrate antigen 19-9 in a multicenter subset analysis of 179 patients with distal cholangiocarcinoma

BackgroundDistal cholangiocarcinoma (DCC) is a rare malignancy and validated prognostic markers remain scarce. We aimed to evaluate the role of serum CA19-9 as a potential biomarker in DCC.MethodsPatients operated for DCC at 6 high-volume surgical centers from 1994 to 2015 were identified from prospectively maintained databases. Patient baseline characteristics, surgical and histopathological parameters, as well as overall survival after resection were assessed for correlation with preoperative bilirubin-adjusted serum carbohydrate antigen 19-9 (CA19-9). Preoperative CA19-9 to bilirubin ratio (CA19-9/BR) was classified as elevated (≥ 25 U/ml/mg/dl) according to the upper serum normal values of CA19-9 (37 U/ml) and bilirubin (1.5 mg/dl) giving a cut-off at ≥ 25 U/ml/mg/dl.ResultsIn total 179 patients underwent resection for DCC during the study period. High preoperative CA19-9/BR was associated with advanced age and regional lymph node metastases. Median overall survival after resection was 27 months. Elevated preoperative serum CA19-9/bilirubin ratio (HR 1.6, p = 0.025), T3/4 stage (HR 1.8, p = 0.022), distant metastasis (HR 2.5, p = 0.007), tumor grade (HR 1.9, p = 0.001) and R status (HR 1.7, p = 0.023) were identified as independent negative prognostic factors following multivariable analysis.ConclusionElevated preoperative bilirubin-adjusted serum CA19-9 correlates with regional lymph node metastases and constitutes a negative independent prognostic factor after resection of DCC.     

Histopathological tumor invasion of the mesenterico-portal vein is characterized by aggressive biology and stromal fibroblast activation

Background

Mesenterico-portal vein resection (PVR) during pancreatoduodenectomy for pancreatic head cancer was established in the 1990s and can be considered a routine procedure in specialized centers today. True histopathologic portal vein invasion is predictive of poor prognosis. The aim of this study was to examine the relationship between mesenterico-portal venous tumor infiltration (PVI) and features of aggressive tumor biology.

A simple scoring system based on clinical factors related to pancreatic texture predicts postoperative pancreatic fistula preoperatively

Background:

Postoperative pancreatic fistula (POPF) is regarded as the most serious complication of pancreatic surgery. The preoperative risk stratification of patients by simple means is of interest in perioperative clinical management.

Methods:

Based on prospective data, we performed a risk factor analysis for POPF after pancreatoduodenectomy in 62 patients operated between 2006 and 2008 with special focus on clinical parameters that might serve to predict POPF. A predictive score was developed and validated in an independent second dataset of 279 patients operated between 2001 and 2010.

Results:

Several pre- and intraoperative factors, as well as underlying pathology, showed significant univariate correlation with rate of POPF. Multivariate analysis (binary logistic regression) disclosed soft pancreatic texture (odds ratio [OR] 10.80, 95% confidence interval [CI] 1.80–62.20) and history of weight loss (OR 0.15, 95% CI 0.04–0.66) to be the only independent preoperative clinical factors influencing POPF rate. The subjective assessment of pancreatic hardness by the surgeon correlated highly with objective assessment of pancreatic fibrosis by the pathologist (r = −0.68, P < 0.001, two-tailed Spearman''s rank correlation). A simple risk score based on preoperatively available clinical parameters was able to stratify patients correctly into three risk groups and was independently validated.

Conclusions:

Preoperative stratification of patients regarding risk for POPF by simple clinical parameters is feasible. Pancreatic texture, as evaluated intraoperatively by the surgeon, is the strongest single predictive factor of POPF. The findings of the study may have important implications for perioperative risk assessment and patient care, as well as for the choice of anastomotic techniques.     

Radiological prediction of portal vein infiltration in patients with pancreatic ductal adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is an aggressive gastrointestinal malignancy characterized by early loco-regional invasion. Portal vein resection (PVR) during pancreatoduodenectomy (PD) for PDAC is performed if tumor cell invasion to the venous wall (PVI) is suspected. The aim of this study is to evaluate radiological criteria for predicting PVR and PVI.MethodsPatients undergoing PD for PDAC were identified from a prospectively maintained database. On the basis of CT- and MRI-based imaging portal vein tumor contact (PV), stranding of the superior mesenteric artery (SMA) and any alterations of the superior mesenterico-portal vein (SMPV) were evaluated. The accuracy of PVI and PVR prediction based on the radiological parameters was calculated.Results143 patients were included in the study. 48 patients underwent PVR (34%), PVI was diagnosed in 23 patients (16%). Median overall survival was 22 months. Prediction of PVR (sensitivity 79%, negative predictive value 88%, p = 0.010) and PVI (sensitivity 95%, negative predictive value 99%, p = 0.002) was most accurate for any SMPV alterations as compared to the other radiological parameters. SMPV alterations qualified as an independent prognostic parameter (26.5 months vs. 33.5months, p = 0.034).ConclusionRadiological evaluation of any SMPV alterations is a simple preoperative method to accurately predict PVI. Assessing SMPV alterations may help to identify candidates for neoadjuvant therapy.