Using multidimensional scaling in model choice for congenital oesophageal atresia: similarity analysis of human autopsy organ weights with those from a comparative assessment of Aachen Minipig and Pietrain piglets

A porcine model of postoperative hemi-diaphragmatic paresis to evaluate a unilateral diaphragmatic pacemaker

Unilateral phrenic nerve damage is a dreaded complication in congenital heart surgery. It has deleterious effects in neonates and children with uni-ventricular circulation. Diaphragmatic palsy, caused by phrenic nerve damage, impairs respiratory function, especially in new-borns, because their respiration depends on diaphragmatic contractions. Furthermore, Fontan patients with passive pulmonary perfusion are seriously affected by phrenic nerve injury, because diaphragmatic contraction augments pulmonary blood flow. Diaphragmatic plication is currently employed to ameliorate the negative effects of diaphragmatic palsy on pulmonary perfusion and respiratory mechanics. This procedure attenuates pulmonary compression by the abdominal contents. However, there is no contraction of the plicated diaphragm and consequently no contribution to the pulmonary blood flow. Hence, we developed a porcine model of unilateral diaphragmatic palsy in order to evaluate a diaphragmatic pacemaker. Our illustrated step-by-step description of the model generation enables others to replicate and use our model for future studies. Thereby, it might contribute to investigation and advancement of potential improvements for these patients.

Paediatric surgical trials, their fragility index, and why to avoid using it to evaluate results

BACKGROUND

The fragility index has been gaining ground in the evaluation of comparative clinical studies. Many scientists evaluated trials in their fields and deemed them to be fragile, although there is no consensus on the definition of fragility. We aimed to calculate the fragility index and its permutations for paediatric surgical trials.

METHODS

We searched pubmed for prospectively conducted paediatric surgical trials with intervention and control group without limitations and calculated their (reverse) fragility indices and respective quotients along with posthoc-power. Relationships between variables were evaluated using Spearman's ρ. We also calculated S values by negative log transformation base-2 of P values.

RESULTS

Of 516 retrieved records, we included 87. The median fragility index was 1.5 (interquartile range: 0-4) and the median reverse fragility index was 3 (interquartile range: 2-4), although they were statistically not different (Mood's test: χ² = 0.557, df = 1, P = 0.4556). P values and fragility indices were strongly inversely correlated (ρ = - 0.71, 95% confidence interval: - 0.53 to - 0.85, P < 0.0001), while reverse fragility indices were moderately correlated to P values (ρ = 0.5, 95% confidence interval: 0.37-0.62, P < 0.0001). A fragility index of 1 resulted from P values between 0.039 and 0.003, which resulted in S values between 4 and 8.

CONCLUSIONS

Fragility indices, reverse fragility indices, and their respective fragility quotients of paediatric surgical trials are low. The fragility index can be viewed as no more than a transformed P value with even more substantial limitations. Its inherent penalisation of small studies irrespective of their clinical relevance is particularly harmful for paediatric surgery. Consequently, the fragility index should be avoided.

Inguinal hernia repair in inpatient children: a nationwide analysis of German administrative data

Background

Contrary to adult inguinal hernia surgery, large-scale investigations using registries or administrative data are missing in paediatric surgery. We aimed to fill this gap by analysing German administrative hospital data to describe the current reality of inpatient hernia surgery in children.

Methods

We analysed aggregated data files bought from the German federals statistics office on hospital reimbursement data separately for principal diagnoses of inguinal hernia in children and for herniotomies in inpatients. Developments over time were assessed via regression and differences between groups with nonparametric comparisons.

Results

Principal diagnoses of hernias were decreasing over time with the exception of male bilateral and female bilateral incarcerated hernias in the first year of life which increased. The vast majority of operations were conducted via the open approach and laparoscopy was increasingly only used for females older than 1 year of age. Recurrent hernia repair was scarce. Rates of inguinal hernia repair were higher in both sexes the younger the patient was, but were also decreasing in all age groups despite a population growth since 2012. The amount of inguinal hernia repairs by paediatric surgeons compared to adult surgeons increased by 1.5% per year.

Conclusions

Our results corroborate previous findings of age and sex distribution. It demonstrates that inpatient hernia repair is primarily open surgery with herniorrhaphy and that recurrences seem to be rare. We observed decreasing rates of hernia repairs over time and as this has been described before in England, future studies should try to elucidate this development.

Level of evidence

III.

A Continuous Suture Anastomosis Outperforms a Simple Interrupted Suture Anastomosis in Esophageal Elongation

INTRODUCTION

 Long-gap esophageal atresia represents a distinct entity among the esophageal atresia spectrum. In many patients, achieving a reasonable anastomosis depends on some millimeters of tissue. We aimed to determine what effect the suturing technique would have on esophageal ex vivo elongation as it may determine the strength of a primary anastomosis.

MATERIALS AND METHODS

 In an analysis of porcine esophagi from animals for slaughter (100-120 days old with a weight of 100-120 kg), we determined esophageal length gain of simple continuous and simple interrupted suture anastomoses subjected to linear traction until linear breaking strength was reached. Statistical power of 80% was ensured based on an a priori power analysis using five specimens per group in a separate exploratory experiment.

RESULTS

 The simple continuous suture anastomosis in 15 porcine esophagi (  = 4.47 cm, 95% confidence interval: 4.08-4.74 cm) outperformed the simple interrupted suture anastomosis in another 15 esophagi (  = 3.03 cm, 95% confidence interval: 2.59-3.43 cm) in length gain (Δ = 1.44 cm, 95% confidence interval: 0.87-2.01 cm, p < 0.0001).

CONCLUSION

 Simple continuous anastomoses achieved higher length gain compared with simple interrupted suture anastomoses. This effect warrants an experimental assessment in vivo to assess its potential merits for clinical applicability.

Circumcision and its alternatives in Germany: an analysis of nationwide hospital routine data

BACKGROUND/PURPOSE

Circumcisions are among the most frequent operations in children. Health service data on circumcision in the United States has documented an increase in neonatal circumcisions since 2012. We investigated whether a similar effect could be found in Germany, which does not endorse neonatal circumcision.

METHODS

We analysed German routine administrative data for operations conducted on the preputium in order to analyse the frequency, age distribution, and time-trends in hospital-based procedures on a nationwide basis.

RESULTS

There were 9418 [95% confidence interval (CI) 8860-10,029] procedures per year, of which 4977 (95% CI 4676-5337) were circumcisions. Age distributions were highly different between both circumcisions (van der Waerden's χ² = 58.744, df = 4, P < 0.0001) and preputium-preserving operations (van der Waerden's χ² = 58.481, df = 4, P < 0.0001). Circumcisions were more frequent in the first 5 years of life and above 15 years of age, whereas preputium-preserving procedures were preferred in the age groups between 5 and 14 years of age. The number of circumcisions and preputium-preserving operations decreased in absolute and relative numbers.

CONCLUSIONS

The increasing trend towards neonatal circumcision observed in the United States is absent in Germany. The majority of patients were operated after the first year of life and absolute and relative numbers of hospital-based procedures were decreasing. Other factors such as increasing use of steroids for the preferred non-operative treatment of phimosis may play a role. As operations in outpatients and office-based procedures were not covered, additional research is necessary to obtain a detailed picture of circumcision and its surgical alternatives in Germany.

LEVEL OF EVIDENCE

III.

Laparoscopy for Abdominal Testes: Nationwide Analysis of German Routine Data

Introduction: Laparoscopy has been used for the evaluation of impalpable testes for more than 30 years. However, its use for intra-abdominal testes has never been evaluated in a population-based approach. Neither has the share of timely orchiopexies of intra-abdominal testes according to published guidelines. We aimed to provide this information by using nationwide administrative data for hospital reimbursements. Materials and Methods: We obtained data for procedures for exploration and orchiopexy of intra-abdominal testes in Germany from 2005 through 2018 and analyzed them with linear regression for the use of laparoscopy and timely repair. Results: In 2005, laparoscopy was already used in more than 60% of explorations, which composed 76% (95% confidence interval [CI]: 72 to 79) of children operated before their first birthday and 68% (95% CI: 65 to 70) of children up to 4 years of age. Throughout the study period, laparoscopy became increasingly popular for orchiopexy of intra-abdominal testes with a yearly increase of 1.8% (95% CI: 1.2 to 2.5, P < .001) in the first year of life and 1.3% (95% CI: 0.2 to 3.4, P < .001) until the age of 4. The share of patients treated before their first birthday increased yearly by 1.9% for explorations and 1.6% for orchiopexies (P < .001 for both) but did not exceed 30% in 2018. Conclusion: Laparoscopy is the method of choice for exploration of intra-abdominal testes and orchiopexy. In this study, more than 70% of boys were treated after their first birthday, thus not meeting the time limit set by guidelines.

Comparing Aachen Minipigs and Pietrain Piglets as Models of Experimental Pediatric Urology to Human Reference Data

INTRODUCTION

Swine had special roles in the development of minimally invasive procedures to treat vesicoureteral reflux, and minipigs have been gaining ground in recent years in experimental pediatric urology as they combine small size with less vulnerable adult physiology, but their suitability as a model has never been assessed. We therefore compared a landrace piglet with a juvenile minipig to elucidate comparability.

METHODS

We evaluated five 3-week old Pietrain piglets and five 3-month old Aachen Minipigs as representatives of landrace and minipig models based on their expected bodyweight being similar to a newborn human. We compared renal weight, volume - via the ellipsoid formula - and ureteral length. In addition, we calculated porcine renal function via Gasthuys' formula. In order to compare the groups with previously published values for infants, we used resampling techniques to allow comparison to humans.

RESULTS

Renal weight was higher in humans than in Pietrain piglets (ΔL = 7.6 g; ΔR = 5.4 g) and Aachen Minipigs (ΔL = 11 g; ΔR = 9.4 g). Renal volumes in humans were higher than in both Pietrain piglets (ΔL = 5.6 mL, p < 0.001; ΔR = 3.7 mL, p = 0.004) and Aachen Minipigs (ΔL = 8.1 mL; ΔR = 6.6 mL; both p < 0.001). Ureteral lengths in humans and both pig breeds were comparable as were estimated renal functions between both pig breeds.

DISCUSSION AND CONCLUSION

Both landrace piglets and juvenile minipigs are suitable models for experimental pediatric urology as parameters did not differ between them. In addition, the anatomic parameters are comparable or smaller than in infants. This might facilitate translational research as technical failure is less likely in larger organs. Additional research is necessary to cover higher age ranges than those included in the present pilot study.