Substitution mutational signatures in whole-genome-sequenced cancers in the UK population

Whole-genome sequencing (WGS) permits comprehensive cancer genome analyses, revealing mutational signatures, imprints of DNA damage and repair processes that have arisen in each patient's cancer. We performed mutational signature analyses on 12,222 WGS tumor-normal matched pairs, from patients recruited via the UK National Health Service. We contrasted our results to two independent cancer WGS datasets, the International Cancer Genome Consortium (ICGC) and Hartwig Foundation, involving 18,640 WGS cancers in total. Our analyses add 40 single and 18 double substitution signatures to the current mutational signature tally. Critically, we show for each organ, that cancers have a limited number of 'common' signatures and a long tail of 'rare' signatures. We provide a practical solution for utilizing this concept of common versus rare signatures in future analyses.

Designing a synthetic simulator to teach open surgical skills for limb exploration in trauma: a qualitative study exploring the experiences and perspectives of educators and surgical trainees

Background

Simulation is an important adjunct to aid in the acquisition of surgical skills of surgical trainees. The simulators used to adequately enable trainees to learn, practice and be assessed in surgical skills need to be of the highest standards. This study investigates the perceived requirements of simulation and simulators used to acquire skills in limb exploratory procedures in trauma.

Methods

Semi-structured interviews were conducted with an international group of 11 surgical educators and 11 surgical trainees who had experience with surgical simulation. The interviews focused on the perceptions of simulation, the integration of simulators within a curriculum and the features of a simulator itself. Interviews were recorded, transcribed and underwent thematic analysis.

Results

Analysis of the perspectives of surgical educators and surgical trainees on simulated training in limb trauma surgery yielded three main themes: (1) Attitudes to simulation. (2) Implementing simulation. (3) Features of an open skills simulator. The majority felt simulation was relevant, intuitive and a good way for procedure warmup and the supplementation of surgical logbooks. They felt simulation could be improved with increased accessibility and variety of simulator options tailored to the learner. Suggested simulator features included greater fidelity, haptic feedback and more complex inbuilt scenarios. On a practical level, there was a desire for cost effectiveness, easy set up and storage. The responses of the educators and the trainees were similar and reflected similar concerns and suggestions for improvement.

Conclusion

There is a clear positive appetite for the incorporation of simulation into limb trauma training. The findings of this will inform the optimal requirements for high quality implementation of simulation into a surgical trauma curriculum and a reference to optimal features desired in simulator or task trainer design.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01417-7.

A new adaptation for a secure surgical drain placement and a comparison with four common drain fixation methods

INTRODUCTION

The importance of postoperative drain fixation cannot be overemphasised. There are numerous described techniques for drain fixation. However, to our knowledge, there is no evidence-based comparison between the various techniques of drain fixation used in postoperative management. We describe a new method and compare its reliability with four other commonly used methods.

MATERIALS AND METHODS

Five methods were chosen for testing based on current trends in clinical practice: centurion sandal with plastic locking ties, centurion sandal or lattice method, centurion sandal with half-inch Steristrips®, double and multiple looped methods. We used an Instron 8872® tensiometer to apply a measured force to a secured drain. Each fixation method was tested ten times and all fixation methods were performed by the same experienced surgeon. We measured the average number of cycles before failure, the average displacement of the tube at failure and the time needed to apply each fixation method.

RESULTS

The number of cycles completed before failure showed that the centurion sandal method, the centurion sandal with plastic ties and the centurion sandal method with Steristrips had the lowest failure rate. The amount of displacement was the least in the centurion sandal with plastic ties followed by the double-loop method and centurion sandal with Steristrips. There was little difference in the time taken to complete the fixation methods (range 21-33 seconds).

DISCUSSION

We recommend the use of the centurion sandal with plastic locking ties, centurion sandal with Steristrips followed by the centurion sandal method alone as fixation techniques that are quick to perform, secure and reliable.

Carotid stump syndrome. A case report and literature review

Carotid stump syndrome occurs infrequently. Diagnosis and management requires flow studies with duplex ultrasound scan as well as anatomical delineation of the affected vessel by magnetic resonance angiography. Surgical exclusion of the internal carotid artery is safe and effective and is the gold standard of treatment with best medical therapy.