A systematic review of endotracheal stenting in patients with locally advanced thyroid cancer.

OBJECTIVE: Locally aggressive thyroid cancer can result in airway obstruction secondary to tracheal compression or vocal cord palsy. A tracheal stent provides an alternative to surgical resection, tracheostomy or conservative management in patients with compressive symptoms. This systematic review synthesises the current evidence associated with tracheal stenting in locally advanced thyroid cancer. DESIGN, SETTING AND PARTICIPANTS: We conducted a systematic review of tracheal stenting in locally advanced thyroid cancers. We searched MEDLINE, Embase and Web of Science for studies until 22 September 2020. Inclusion criteria were studies involving patients who had received tracheal stents to treat laryngotracheal stenosis secondary to locally advanced thyroid cancer. Single case reports or single cases were not included. MAIN OUTCOME MEASURES: We assessed studies for data on the performance of tracheal stenting; defined as symptomatic relief, spirometry data, complication rates and mortality. We also extracted data pertaining to the use of different types of stent. RESULTS: We identified eight full-text articles from 325 titles found in our search. These were all single-centre retrospective studies that lacked homogeneity of thyroid cancer histotypes. The number of patients in each study ranged from 4 to 35 patients. Stenting improved performance status (two of two studies), symptoms (five of five studies) and spirometry (two of three studies). The most common complications were tracheal granulation, tumour overgrowth, stent migration and sputum retention. CONCLUSION: There is a lack of evidence in the literature of tracheal stents in locally advanced thyroid cancer. However, the evidence available suggests tracheal stenting may be a useful treatment adjunct in advanced thyroid cancer-causing symptomatic airway obstruction.

Outcomes of elective head and neck confirmed or suspected cancer surgery during the COVID-19 pandemic.

PURPOSE: To analyse the complication outcomes of COVID-19 negative patients undergoing elective head and neck surgery during the COVID-19 pandemic. METHODS: This was a retrospective case review of all patients undergoing elective head and neck surgery for confirmed or suspected head and neck cancer. RESULTS: There were no mortalities recorded in the cohort of patients analysed. At 30 days, pulmonary complications had occurred in 4 patients (9%). None of these were related to COVID infection. CONCLUSION: With careful pre-operative screening of patients for COVID-19 and post-operative care in a COVID-19 clean ward, head and neck surgery can proceed safely during the epidemic. This data could help to minimise delay in treatment by allowing a greater number of elective head and neck cancer operations to proceed.

Multi-analyte profiling in human carotid atherosclerosis uncovers pro-inflammatory macrophage programming in plaques.

Molecular characterisation of vulnerable atherosclerosis is necessary for targeting functional imaging and plaque-stabilising therapeutics. Inflammation has been linked to atherogenesis and the development of high-risk plaques. We set to quantify cytokine, chemokine and matrix metalloproteinase (MMP) protein production in cells derived from carotid plaques to map the inflammatory milieu responsible for instability. Carotid endarterectomies from carefully characterised symptomatic (n=35) and asymptomatic (n=32) patients were enzymatically dissociated producing mixed cell type atheroma cell suspensions which were cultured for 24 hours. Supernatants were interrogated for 45 analytes using the Luminex 100 platform. Twenty-nine of the 45 analytes were reproducibly detectable in the majority of donors. The in vitro production of a specific network of mediators was found to be significantly higher in symptomatic than asymptomatic plaques, including: tumour necrosis factor α, interleukin (IL) 1ß, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), CCL5, CCL20, CXCL9, matrix metalloproteinase (MMP)-3 and MMP-9. Ingenuity pathway analysis of differentially expressed analytes between symptomatic and asymptomatic patients identified a number of key biological pathways (p< 10(-25)). In conclusion, the carotid artery plaque culprit of ischaemic neurological symptoms is characterised by an inflammatory milieu favouring inflammatory cell recruitment and pro-inflammatory macrophage polarisation.

Laboratory testing of the Pressio intracranial pressure monitor.

OBJECTIVE: The Sophysa Pressio (Sophysa Ltd., Orsay, France) is a new intracranial pressure monitoring system. This study aimed to evaluate its accuracy and compare it with the popular Codman intracranial pressure transducer (Codman/Johnson & Johnson, Raynham, MA) in vitro. METHODS: A computerized rig was used to test the Pressio and Codman transducers simultaneously. Properties that were tested included drift over 7 days, the effect of temperature on drift, frequency response, the accuracy of measurement of static and pulsatile pressures, and connectivity of the system. RESULTS: Long-term (7 d) relative zero drift was less than 0.05 mmHg. The temperature drift was low (0.3 mmHg/207C). Absolute static accuracy was better than 0.5 mmHg over the range of 0 to 100 mmHg. Pulse waveform accuracy, relative to the Codman transducer, was better than 0.2 mmHg over the range of 1 to 20 mmHg. The frequency bandwidth of the Pressio transducer was 22 Hz. The Pressio monitor can transmit data directly to an external computer without the use of a pressure bridge amplifier. CONCLUSION: The new Pressio transducer proved to be accurate for measuring static and dynamic pressure during in vitro evaluation.

Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt.

BACKGROUND: The Polaris valve is a newly released hydrocephalus shunt that is designed to drain cerebrospinal fluid (CSF) from the brain ventricles or lumbar CSF space. The aim of this study was to bench test the properties of the Polaris shunt, independently of the manufacturer. METHODS: The Polaris Valve is a ball-on-spring valve, which can be adjusted magnetically in vivo. A special mechanism is incorporated to prevent accidental re-adjustment by an external magnetic field. The performance and hydrodynamic properties of the valve were evaluated in the UK Shunt Evaluation Laboratory, Cambridge, UK. RESULTS: The three shunts tested showed good mechanical durability over the 3-month period of testing, and a stable hydrodynamic performance over 45 days. The pressure-flow performance curves, operating, opening and closing pressures were stable. The drainage rate of the shunt increased when a negative outlet pressure (siphoning) was applied. The hydrodynamic parameters fell within the limits specified by the manufacturer and changed according to the five programmed performance levels. Hydrodynamic resistance was dependant on operating pressure, changing from low values of 1.6 mmHg/ml/min at the lowest level to 11.2 mmHg/ml/min at the highest performance level. External programming proved to be easy and reliable. Even very strong magnetic fields (3 Tesla) were not able to change the programming of the valve. However, distortion of magnetic resonance images was present. CONCLUSION: The Polaris Valve is a reliable, adjustable valve. Unlike other adjustable valves (except the Miethke ProGAV valve), the Polaris cannot be accidentally re-adjusted by an external magnetic field.

Laboratory study on "intracranial hypotension" created by pumping the chamber of a hydrocephalus shunt.

BACKGROUND: It has been reported that pumping a shunt in situ may precipitate a proximal occlusion, and/or lead to ventricular over-drainage, particularly in the context of small ventricles. In the laboratory we measured the effect of pumping the pre-chamber of hydrocephalus shunts on intracranial hypotension. MATERIALS AND METHODS: A simple physical model of the CSF space in a hydrocephalic patient was constructed with appropriate compliance, CSF production and circulation. This was used to test eleven different hydrocephalus shunts. The lowest pressure obtained, the number of pumps needed to reach this pressure, and the maximum pressure change with a single pump, were recorded. RESULTS: All models were able to produce negative pressures ranging from -11.5 mmHg (Orbis-Sigma valve) to -233.1 mmHg (Sinu-Shunt). The number of pumps required reaching these levels ranged from 21 (PS Medical LP Reservoir) to 315 (Codman Hakim-Programmable). The maximum pressure change per pump ranged from 0.39 mmHg (Orbis-Sigma valve) to 23.1 (PS Medical LP Reservoir). CONCLUSION: Patients, carers and professionals should be warned that 'pumping' a shunt's pre-chamber may cause a large change in intracranial pressure and predispose the patient to ventricular catheter obstruction or other complications.

In vitro hydrodynamic properties of the Miethke ProGAV hydrocephalus shunt.

BACKGROUND: Adjustable shunts are very popular in the management of hydrocephalus and are believed to help in minimizing the number of surgical revisions. The drawback with almost all constructions is that they may be accidentally readjusted in relatively weak magnetic fields (around 30-40 mTesla) MATERIALS AND METHODS: The ProGav Miethke shunt is composed of an adjustable balloon-spring valve unit and an integrated over-drainage compensating gravitational device (known as the shunt assistant). A mechanical 'brake' is intended to prevent changes to the valve's performance level in a strong magnetic field. We evaluated the performance and hydrodynamic properties of a sample of three valves in the UK Shunt Evaluation Laboratory. RESULTS: All the shunts showed good mechanical durability over the three-month period of testing, and good stability of hydrodynamic performance over a one-month period. The pressure-flow performance curves, operating, opening and closing pressures fell within the limits specified by the manufacturer, and changed according to the programmed performance levels. The operating pressure increased when the shunt assistant was in the vertical position, as specified. The valve has a low hydrodynamic resistance (0.53 mm mmHg ml(-1) min(-1)). External programming proved to be easy and reliable. Strong magnetic fields from a 3 Tesla MR scanner were not able to change the programming of the valve. CONCLUSION: The ProGAV shunt is an adjustable, low resistance valve that is able to limit posture-related over-drainage. Unlike other adjustable valves, the ProGAV cannot be accidentally re-adjusted by external magnetic field such as a 3T MR scanner.