The RCS England COVID-19 Surgical Research Group: early findings and lessons to influence surgical practice.

INTRODUCTION: Surgeons and allied professionals have been quick to respond to the need for evidence during the COVID-19 pandemic. The Royal College of Surgeons of England (RCS England) has provided formal recognition, support and guidance to all members of its interdisciplinary collaborative COVID Research Group (RCS CRG). We describe research conducted by members of this group, initial findings and lessons for clinical practice so far. METHODS: Members of the more than 50 projects included so far in the RCS CRG portfolio were invited to provide a summary of their project and findings to date. The 26 summaries received were collated and broad themes identified to produce this summary document. RESULTS: Wide-ranging projects have been conducted by members of the RCS CRG, rapidly yielding crucial insights into the behaviour of the SARS-CoV-2 pathogen, its impact on patients and staff, the challenges it presents to surgical practice and investigation into methods to adapt and overcome such challenges. CONCLUSIONS: The response of the surgical research community to COVID-19 has been rapid and well-organised. Early establishment of a formal network under the auspices of RCS England has assisted efficient research collaboration and delivery, while avoiding academic duplication between groups. This has led to a high research output, directly informing and substantially influencing practice throughout and beyond the pandemic.

The dispersion of spherical droplets in source-sink flows and their relevance to the COVID-19 pandemic.

In this paper, we investigate the dynamics of spherical droplets in the presence of a source-sink pair flow field. The dynamics of the droplets is governed by the Maxey-Riley equation with the Basset-Boussinesq history term neglected. We find that, in the absence of gravity, there are two distinct behaviors for the droplets: small droplets cannot go further than a specific distance, which we determine analytically, from the source before getting pulled into the sink. Larger droplets can travel further from the source before getting pulled into the sink by virtue of their larger inertia, and their maximum traveled distance is determined analytically. We investigate the effects of gravity, and we find that there are three distinct droplet behaviors categorized by their relative sizes: small, intermediate-sized, and large. Counterintuitively, we find that the droplets with a minimum horizontal range are neither small nor large, but of intermediate size. Furthermore, we show that in conditions of regular human respiration, these intermediate-sized droplets range in size from a few µm to a few hundred µm. The result that such droplets have a very short range could have important implications for the interpretation of existing data on droplet dispersion.

A novel patient-controlled bidirectional palatal lift appliance.

OBJECTIVE: Palatal lift appliances have a role in management of velopharyngeal dysfunction for immobile palates of adequate length where surgery is contraindicated. Conventional appliances involve acrylic/wire work adjustment over successive appointments until they can be tolerated without gagging. A novel appliance has been developed where the lifting plate is incrementally distalized by the patient and vertically adjusted to optimize soft palate positioning. METHOD: The design, construction, and utility of the appliance, which was developed in Dundee Dental Hospital, are described. PARTICIPANTS: The subject was a 12-year-old boy with a variant of Moebius syndrome and velopharyngeal dysfunction. Previous pharyngoplasty had been carried out and further surgery was contraindicated. INTERVENTIONS: The appliance is constructed and fitted and the flexible spring arm is vertically adjusted to lift the soft palate. The screw is turned incrementally at home, extending the lifting plate posteriorly. Videofluoroscopy allows visualization of the appliance and soft palate positioning. MAIN OUTCOME MEASURES/RESULTS: The procedure improved soft palate positioning, as demonstrated by videofluoroscopy, and objective speech outcomes. CONCLUSIONS: The appliance was well tolerated and led to improved speech outcomes for the patient. Adjustments were quick and easy for both clinician and patient. Further studies are needed to definitively determine the efficacy of the appliance.

Airway obstruction due to a rudimentary premaxilla in holoprosencephaly.

OBJECTIVE: We present two infants with holoprosencephaly and clefts of the primary palate, who developed nasal airway obstruction due to a previously undocumented cause: a ball-valve-like action of a rudimentary premaxilla, which was extremely mobile on a soft tissue stalk. In such patients, the importance of intranasal examination to identify a rudimentary premaxilla, in order to preserve it, and if necessary, surgically stabilize it, is illustrated.

A modified gag for cleft palate repair.

A number of modifications of the tongue blade of the Dott mouth gag for cleft palate surgery are described and illustrated. These modifications facilitate cleft palate surgery, especially on small infants and patients with micrognathia, as well as surgery under the microscope and also reduce the risk of compression of the endotracheal tube.