Impact of rhythm in non-valvular atrial fibrillation on four cardiac chamber deformation imaging

Background

Few studies have assessed the evolution of cardiac chambers deformation imaging in patients with atrial fibrillation (AF) according to cardiac rhythm outcome.

Purpose

To evaluate cardiac chamber deformation imaging in patients admitted for AF and the evolution at 6-month follow-up (M6).

Methods

In forty-one consecutive patients hospitalised for AF two-dimensional transthoracic echocardiography was performed at admission (M0) and after six months (M6) of follow up. In addition to the usual parameters of chamber size and function, chamber deformation imaging was obtained including global left atrium (LA) and right atrium (RA) reservoir strain, global left ventricular (LV) and right ventricular (RV) free wall longitudinal strain. Patients were divided into three groups according to their cardiac rhythm at M0 and M6: AF at M0 and sinus rhythm (SR) at M6 (AF-SR) (n=23), AF at M0 and AF at M6 (AF-AF) (n=11), SR at M0 (spontaneous conversion before the first echocardiography exam) and SR in M6 (SR-SR) (n=7)

Results

In comparison with SR patients (n=7), at M0, AF patients (n=34)) had lower global LA reservoir strain (+5.2 (+0.4 to 12.8) versus +33.2 (+27.0 to +51.5)%; p<0.001), lower global RA reservoir strain (+8.6 (−5.4 to 11.6) versus +24.3 (+12.3 to +44.9)%; p<0.001), lower global LV longitudinal strain (respectively −12.8 (−15.2 to −10.4) versus −19.1 (−21.8 to −18.3)%; p<0.001) and lower global RV longitudinal strain (respectively −14.2 (−17.3 to −10.7) versus −23.8 (−31.1 to −16.2)%; p=0.001). When compared with the AF-SR group at M0 the AF-AF group had no significant differences with regard to global LA and RA reservoir strain, global LV and RV longitudinal strain (Table). Between M0 and M6 there was a significant improvement in global longitudinal strain of the four chambers in the AF-SR group whereas no improvements were noted in the AF-AF and SR-SR group (Figure).

Conclusion

Initial atrial and ventricular deformations were not associated with rhythm outcome at six-month follow up in AF. The improvement in strain in all four chambers strain suggests global reverse remodelling all cardiac cavities with the restoration of sinus rhythm.

Evolution of strain between M0 and M6

Funding Acknowledgement

Type of funding source: None

Psychological interventions for acute psychiatric inpatients with schizophrenia-spectrum disorders: A systematic review and meta-analysis

BACKGROUND

Acute inpatient psychiatric wards are important yet challenging environments in which to implement psychological interventions for people with schizophrenia-spectrum disorders. No meta-analysis to date has evaluated whether psychological interventions are effective in this context.

METHODS

We systematically searched Embase, Medline and PsycInfo databases for randomised controlled trials (RCTs) of psychological interventions implemented in acute inpatient psychiatric settings with individuals with schizophrenia-spectrum disorders. We conducted random effects meta-analyses of between-groups outcomes at post-intervention and relapse/re-hospitalisation rates by follow-up.

RESULTS

Twenty-nine trials were suitable for meta-analysis. Psychological interventions improved post-intervention positive symptoms, social functioning and treatment compliance and reduced the risk of relapse/ re-hospitalisation, relative to control conditions. Analyses of specific intervention effects found positive effects of psychoeducation on several key outcomes (power > 80%) and preliminary evidence for positive effects of acceptance and commitment therapy (ACT), cognitive behaviour therapy (CBT) and metacognitive training (MCT) on some outcomes (power < 80%).

CONCLUSION

Psychological interventions can be helpful for acute inpatients with schizophrenia-spectrum disorders. However, risk of bias was often high or unclear, and some analyses were underpowered. Further research should use more rigorous RCT designs and publish meta-analysable data on positive symptoms, general psychopathology, relapse/ re-hospitalisation, social functioning and treatment compliance.

[The microbiome in head and neck tumors-initial findings and outlook]

Technical progress in molecular biology has allowed for a more detailed analysis of the composition of the human microbiome in recent years. Inter- and intraindividual differences in microbiome composition have been demonstrated, which in part correlate with the occurrence of certain diseases. For some of the so-called oncomicrobes, a direct relationship between their effect on the host organism and carcinogenesis has been demonstrated, predominantly for gastrointestinal cancers. Initial results for head and neck cancer show inter- and intraindividual differences in the local microbiota of the tumor environment, with certain bacterial strains over- or underrepresented. Our results confirm these findings, e.g., by showing a relative abundance of fusobacteria in tumor tissue while streptococci were relatively reduced. Currently available results show a high degree of inter- and intraindividual variation, thus requiring larger patient cohorts for functional analyses.

[Exosomes as immune regulators in head and neck cancer]

Exosomes, virus-sized nanovesicles, are utilized as messenger systems of our body to communicate with other body cells and regulate immune functions. Almost all cells produce exosomes and are able to interact with immune cells in the blood stream and peripheral body areas. Different markers on the surface of exosomes are necessary for immune cell adhesion and interaction. Furthermore, many types of exosome-immune cell interaction, such as surface receptor contact and phagocytosis, are known. As carriers of different cargos, exosomes affect different immune cell types in head and neck cancers: So far, T cells, natural killer cells, macrophages, and dendritic cells have been described in this context. For diagnostic purposes, a combined analysis of different parameters including protein amount, nucleic acid/protein expression, and the immunosuppressive impact of exosomes could empower exosomes as useful tools for evaluation of tumor promotion and progression in the future.

[Effects of the SARS-CoV-2 pandemic on the otorhinolaryngology university hospitals in the field of medical care]

INTRODUCTION

Since December 2019, the SARS-CoV-2 virus has been rapidly spreading worldwide. In Germany, an exponential increase in the number of infections was registered at the beginning of March 2020 and led to a call of the Ministry of Health to create more capacity for intensive medical treatment in hospitals. The aim of the present study was to determine the effects of the SARS-CoV-2 pandemic on Oto-Rhino-Laryngology (ORL) university hospitals regarding patient care.

MATERIALS AND METHODS

An online survey was sent out to all chairmen of the 39 ORL university hospitals in Germany. The answers to the questions referred to the defined period from March 15^th to April 15^th 2020 and were carried out using the online survey tool "SurveyMonkey". 87 questions focused on general information, health care, and structural effects in the respective institution.

RESULTS

All chairmen of the 39 university hospitals in Germany participated in the survey. The collected data prove the considerable impact on organizational, structural and medical aspects of patient care. For example, the surveyed clinics reported a decrease in outpatient cases by 73.8 % to 26.2 ± 14.2 % and in surgical treatments by 65.9 % to 34.1 ± 13.9 %. In contrast, emergency treatment remained unchanged or even increased in 80 % of the facilities and surgical treatment of emergency patients remained unchanged or even increased in more than 90 %. Emergency outpatient and surgical treatment of patients was provided throughout the pandemic in all facilities. In total, about 35 000 outpatients and about 12 000 surgical cases were postponed. As a result of the acute structural changes, the potential danger of falling below current treatment standards was seen in individual areas of patient care.

DISCUSSION

The assessment of the impact of the SARS-CoV-2 pandemic is heterogeneous. The majority of the chairmen are critically aware of the risk of falling below current medical treatment standards or guidelines. In the phase of an exponential increase in the number of infections, significant changes in treatment processes had to be accepted for understandable reasons. However, with the currently significantly reduced number of infections, falling below treatment standards and guidelines should not be allowed to remain constant and tolerated.

SUMMARY

This study shows a differentiated picture with regard to the effects of the SARS-CoV-2 pandemic on outpatient, inpatient and operative patient care at the ORL university hospitals in Germany and illustrates the importance of these institutions for ensuring patient care during this critical phase.

[Primary cutaneous CD4+ small to medium-sized T-cell lymphoma in an adolescent patient]

A rare finding of primary cutaneous CD4+ small to medium-sized T‑cell lymphoma (SMPTCL) in a fifteen-year-old patient is reported. This is a rare tumor entity for which there is currently no standardized treatment recommendation. At the interdisciplinary tumor board, the decision was made to resect the tumor and reconstruct the defect with a nasolabial advancement flap in a two-stage process. Follow-up examinations, currently over 3 years, have shown the patient to be free of recurrences.

[The role of surgery and salvage surgery in the era of HPV-associated oropharyngeal carcinomas]

The incidence of human papillomavirus (HPV)-positive oropharyngeal carcinomas is increasing worldwide. Due to a markedly different response to treatment compared to HPV-negative oropharyngeal carcinomas, determining the ideal therapeutic approach can be challenging. Particularly in never-smokers, HPV-positive oropharyngeal carcinomas respond well to primary radiation therapy; at the same time recent studies indicate comparable survival after primary surgery. For stage I tumors according to TNM‑8, retrospective analyses show very good oncologic outcomes after surgery alone, and no added benefit of adjuvant radio- or chemotherapy. Results of prospective treatment deintensification trials are expected in the coming years. Minimally invasive transoral surgical approaches for selected oropharyngeal cancers can improve preservation of postoperative function and quality of life. For both HPV-positive and HPV-negative oropharyngeal carcinomas, salvage surgery is the treatment of choice for resectable recurrent locoregional disease and resectable distant metastases.

P350 Right atrial remodelling in atrial fibrillation using three dimensional transthoracic echocardiography and strain imaging

Background

Evaluation of right atrial cavities and right atrial (RA) remodelling in atrial fibrillation (AF) has been poorly studied.

Purpose

The aim of this study was to evaluate in AF, the role of three-dimensional (3D) transthoracic echocardiography (TTE) and strain to refine the evaluation of the RA according to evolution of cardiac rhythm ad mid-term follow-up.

Methods

A complete 2D and 3D TTE was performed in patient hospitalized for AF. In addition to the usual parameters, RA parameters were specifically assessed: 3D RA end-systolic (ES) and end-diastolic (ED) volume, RA ejection fraction (EF) and the global longitudinal strain (GLS) of the RA. A complete clinical evaluation and electrocardiogram were performed at admission (M0) and 6 months after inclusion (M6) to determine the cardiac rhythm at follow-up.

Results

34 consecutive patients hospitalized for AF were analysed. At M0, there was no significant difference between 2D RA ES volume and the 3D RA ES volume. Three groups of patients were individualized according to cardiac rhythm at M0 and M6: AF at M0 and AF at M6 (AF-AF), AF at M0 and sinus rhythm (SR) at M6 (AF-SR), SR at M0 (spontaneous reduction before the admission ECG) and SR at M6 (SR-SR). At M0 echocardiography, in the AF-AF group and AF-SR in comparison with SR-SR group were as follow: the 3D RA ED volume was significantly higher (respectively 21.6 (18.2-26.6) and 26.9 (19.4-36.8) versus 11.3 (6.9-16.6) mL/m2 ; p = 0.0025), the 3D RAEF was significantly lower (42.2 (35.1-44.7) and 34.5 (24.1-38.6) versus 57.6 (53.4-62.2)%; p = 0.0105) and the RA GLS was also significantly lower (7.6 (6.5-10.5) and 9.1 (5.8-11.2) versus 26.6 (22.0-35.0)%; p = 0.0001) (Figure 1).

Conclusion

3D ultrasound and strain could be useful tools for evaluating the anatomical and functional RA remodelling in AF, to be further validated in a larger ongoing study.

Abstract P350 Figure 1

Assessing the validity of EQ-5D-5L in people with head & neck cancer: Does a generic quality of life measure perform as well as a disease-specific measure in a patient population?

BACKGROUND

Head and neck cancer (HNC) is an important cause of morbidity and mortality globally. Radical treatment methods may result in facial disfigurement and/or functional difficulties with subsequent adverse impacts on health-related quality of life (HRQoL). Guidelines suggest that HRQoL should be measured repeatedly throughout treatment to enable refined treatment protocols and tailored follow-up support but questionnaires are often long and burdensome. We compared condition-specific and generic metrics to assess HRQoL for people with this condition.

METHODS

We used data from the prospective Head and Neck 5000 clinical cohort study - 5511 participants with a new diagnosis of HNC between 2011 and 2014. HRQoL data were collected at baseline from 2065 people who completed both the condition-specific EORTC-QLQ-C30 and the shorter, generic EQ-5D-5L questionnaires.

RESULTS

There was strong evidence of association between comparable scales on each questionnaire at baseline: higher levels of functioning and lower levels of reported symptoms assessed with EQ-5D-5L were associated with lower EORTC-QLQ-C30 symptom scores. A moderate relationship (0.61) was found between overall QoL in the EQ-5D-5L index and self-perceived health (EQ VAS).

CONCLUSIONS

HRQoL data collected from the generic EQ-5D-5L and cancer-specific EORTC-QLQ-C30 questionnaires are comparable at baseline for people diagnosed with HNC. This would allow a reduced burden of data collection but the EQ-5D-5L may not be sensitive to some condition-specific symptoms. Clinicians and researchers must clarify their aims and outcomes of interest before choosing their HRQoL measures. Further work is required to examine the ability to detect change in these measures over time.

[Surgical management of firework-induced eyelid injuries]

Fireworks injuries are frequently caused by malfunction or incorrect operation of fireworks. Injuries often affect the eyeball and the periorbit. After treatment of life-threatening bleeding, injuries of the eyeball have priority over the treatment of periorbital lacerations and burns. The aim of eyelid surgery in firework-related injuries is to prevent delayed damage, such as lagophthalmos, symblepharon, entropion with trichiasis, and keratinization of the conjunctiva of the eyelid and eyelid margin. The treatment requires a considerable amount of time and patience both for the elaborate surgical procedures as well as for the necessary healing and rest phases. Many patients, however, are left with serious visual impairments and stressful esthetic deformities, which result in considerable occupational and social impairments.

P5338Atherosclerotic cardiovascular events in people living with Human Immunodeficiency Virus

Background

People living with Human Immunodeficiency Virus (PLWHIV) under antiretrovirals have an increased risk of atherosclerotic cardiovascular disease (ASCVD) events. The risk factors associated with ASCVD events in this high risk population are various including traditional vascular risk factors and specific HIV-related factors. However their respective influence is questionable.

Purpose

Our aim was to determine the incidence of ASCVD events in a large cohort of PLWHIV and to identify the risk factors associated.

Methods

We conducted a longitudinal observational cohort study of asymptomatic PLWHIV at high risk of ASCVD addressed to our preventive cardiovascular unit for non-invasive cardiovascular evaluation. The first ASCVD event was censored and included CV death, acute coronary syndromes, coronary and peripheral revascularizations (PCI or CABG or endarterectomy or limb procedures) and ischemic strokes.

Results

From January 2003 to December 2014, 763 consecutive asymptomatic PLWHIV were enrolled (mean age of 51.3±8.3 years, 87% men, 90% were free of known coronary artery disease, mean Left ventricular ejection fraction 60%). At baseline, traditional CV risk factors were as follow: 54% had dyslipidemia, 43% hypertension, 35% were active smokers, 22% had family history of CAD and 11% were diabetics. Statins were prescribed in 38% of the cohort, aspirin in 14%, clopidogrel in 14% betablockers in 14%, RAS blockers in 32%, Calcium channel blockers in 8%. At baseline, median duration of HIV seropositivity was 19.8 years (14.0–23.6), 94% were under ARV predominantly protease inhibitors (68%). Median CD4 cell count was 545/mm3 (404–745) and 92% had undetectable HIV viral load. During a median follow up of 5.8 years (3.7–8.7), 58 (7.3%) subjects had a first ASCVD event (incidence of 12.70 [9.78–16.51] per 1000 persons-years) including 5 cardiovascular deaths, 14 ACS, 20 coronary revascularizations, 13 peripheral vascular procedures and 6 strokes) with a median time of occurrence of 3.1 years (1.5–5.1). CV death (first and second ASCVD events) occurred in 8 patients (22%) after CV death related to malignancies (33%) but before deaths related to unexplained causes (21%), infectious disease (13%), liver disease (8%) and suicides (3%). Coronary events including coronary death, MI, and coronary revascularization occurred in 39 patients (5.2%); Incidence of 8.28 [6.00–11.43] per 1000 persons-years. Conventional multivariate Cox model shows that age and tobacco were the independent risk factors associated with ACSVD events [Hazard ratio (HR) 1.04, 95% CI 0.99–1.09, p=0.05 and HR 2.17, 95% CI 1.07–4.38, p=0.03].

Conclusion

Traditional vascular risk factors (age and active smoking) are associated with the occurrence of ASCVD events predominantly coronary artery disease in our observational cohort of asymptomatic PLWIHV at high risk for ASCVD. Cardiovascular prevention including tobacco cease action is mandatory in the aging HIV population.

1206Doxapram is a promising new antiarrhythmic drug for an atrial-specific therapy of atrial fibrillation

Background

TASK-1 (K2P3.1) is an atrial-specific two-pore domain potassium channel that is significantly upregulated in atrial fibrillation (AF) patients resulting in shortened atrial action potential duration (APD). Inhibition of TASK-1 in human atrial cardiomyocytes reverses AF-related APD shortening to values observed in patients with sinus rhythm (SR). By in silico-modelling and experimental characterization of drug binding sites, doxapram was identified as specific inhibitor of TASK-1.

Purpose

In this study, we investigated the antiarrhythmic efficacy of doxapram in a porcine model of AF to convert and suppress AF.

Methods

We established a new porcine model of persistent AF without induced tachymyopathy. AF was induced in domestic pigs by intermittent atrial burst stimulation using implanted pacemakers. During AF episodes, burst stimulation was inhibited by an integrated pacemaker biofeedback algorithm. AV-node ablation was performed to prevent AF-associated heart failure. All pigs underwent catheter-based electrophysiological investigations prior to and after 14 days doxapram treatment. Pigs in the treatment group received intravenous applications of doxapram twice per day. Rhythm status was continuously recorded by intracardiac long-term ECG monitors. The application of doxapram for cardioversion and long term suppression of AF in pigs with persistent AF was evaluated. Subsequent to the doxapram treatment, porcine cardiomyocytes were isolated from right and left atria and electrophysiologically investigated by patch-clamp and multi-electrode experiments. Atrial electrical remodeling was characterized by analyses of ion channel expression at mRNA and protein levels.

Results

TASK-1 mRNA, protein and transmembrane current were significantly increased in AF pigs compared to SR controls, resulting in shortened atrial APDs. In doxapram-treated AF pigs the AF burden was significantly reduced. After 14 days treatment with doxapram, TASK-1 currents and atrial APDs recorded in porcine cardiomyocytes were reduced and similar to values of SR animals. Doxapram could be successfully applied for cardioversion in pigs with persistent AF. On average, cardioversion was observed 3 minutes after doxapram application.

Conclusion

Doxapram significantly suppressed AF episodes and normalized cellular electrophysiological characteristics in a porcine model of AF through inhibition of the TASK-1 ion channel. Furthermore, doxapram rapidly converted AF into SR in pigs. Therefore, doxapram might serve as a new antiarrhythmic drug to treat AF in patients.

Quantitative and Qualitative Comparison of 4D-DSA with 3D-DSA Using Computational Fluid Dynamics Simulations in Cerebral Aneurysms

BACKGROUND AND PURPOSE

4D-DSA allows time-resolved 3D imaging of the cerebral vasculature. The aim of our study was to evaluate this method in comparison with the current criterion standard 3D-DSA by qualitative and quantitative means using computational fluid dynamics.

MATERIALS AND METHODS

3D- and 4D-DSA datasets were acquired in patients with cerebral aneurysms. Computational fluid dynamics analysis was performed for all datasets. Using computational fluid dynamics, we compared 4D-DSA with 3D-DSA in terms of both aneurysmal geometry (quantitative: maximum diameter, ostium size [OZ1/2], volume) and hemodynamic parameters (qualitative: flow stability, flow complexity, inflow concentration; quantitative: average/maximum wall shear stress, impingement zone, low-stress zone, intra-aneurysmal pressure, and flow velocity). Qualitative parameters were descriptively analyzed. Correlation coefficients (r, P value) were calculated for quantitative parameters.

RESULTS

3D- and 4D-DSA datasets of 10 cerebral aneurysms in 10 patients were postprocessed. Evaluation of aneurysmal geometry with 4D-DSA (r _{maximum diameter} = 0.98, P _{maximum diameter} <.001; r _OZ1/OZ2 = 0.98/0.86, P _OZ1/OZ2 < .001/.002; r _volume = 0.98, P _volume <.001) correlated highly with 3D-DSA. Evaluation of qualitative hemodynamic parameters (flow stability, flow complexity, inflow concentration) did show complete accordance, and evaluation of quantitative hemodynamic parameters (r _{average/maximum wall shear stress diastole} = 0.92/0.88, P _{average/maximum wall shear stress diastole} < .001/.001; r _{average/maximum wall shear stress systole} = 0.94/0.93, P _{average/maximum wall shear stress systole} < .001/.001; r _{impingement zone} = 0.96, P _{impingement zone} < .001; r _{low-stress zone} = 1.00, P _{low-stress zone} = .01; r _{pressure diastole} = 0.84, P _{pressure diastole} = .002; r _{pressure systole} = 0.9, P _{pressure systole} < .001; r _{flow velocity diastole} = 0.95, P _{flow velocity diastole} < .001; r _{flow velocity systole} = 0.93, P _{flow velocity systole} < .001) did show nearly complete accordance between 4D- and 3D-DSA.

CONCLUSIONS

Despite a different injection protocol, 4D-DSA is a reliable basis for computational fluid dynamics analysis of the intracranial vasculature and provides equivalent visualization of aneurysm geometry compared with 3D-DSA.

Nasal self-packing for epistaxis in Hereditary Hemorrhagic Telangiectasia increases quality of life

STATEMENT OF PROBLEM

Hereditary hemorrhagic telangiectasia (HHT) is characterized by recurrent epistaxis that can lead to a feeling of losing control. We assessed potential benefits and side effects of different nasal packings used by patients themselves.

METHOD OF STUDY

An online-questionnaire in English and German was used to analyze nasal self-packings.

RESULTS

588 of the 915 respondents suffered from HHT with most of them having moderate or severe epistaxis. Almost two thirds of the patients had already treated themselves with nasal packings. While one quarter used non-pneumatic nasal packings (NPNP) or pneumatic nasal packings (PNP), nearly half of the patients took only tissues to stop the bleeding. Patients with severe epistaxis used PNP more often than NPNP. Using nasal packings, most patients could stop their nosebleeds after a while. Patients using PNP reported the feeling of losing control less often and significant improvements in quality of life with a positive GBI.

CONCLUSIONS

Our study showed that most patients with HHT using nasal self-packings could stop the bleeding after a while. Nasal self-packing is a user-friendly and secure method leaving patients more self-confident and independent.

Expanding the Goddard CSH Algorithm for GPM: New Extratropical Retrievals

The Goddard Convective-Stratiform Heating (CSH) algorithm has been used to retrieve latent heating (LH) associated with clouds and cloud systems in support of the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) mission. The CSH algorithm required the use of a cloud-resolving model (CRM) to simulate LH profiles to build look-up tables (LUTs). However, the current LUTs in the CSH algorithm are not suitable for retrieving LH profiles at high latitudes or winter conditions that are needed for GPM. The NASA Unified-Weather Research and Forecasting (NU-WRF) model is used to simulate three eastern continental US (CONUS) synoptic winter and three western coastal/offshore events. The relationship between LH structures (or profiles) and other precipitation properties (radar reflectivity, freezing level height, echo-top height, maximum radar reflectivity height and surface precipitation rate) is examined, and a new classification system is adopted with varying ranges for each of these precipitation properties to create LUTs representing high latitude/winter conditions. The performance of the new LUTs is examined using a self-consistency check for one CONUS and one West Coast offshore event by comparing LH profiles retrieved from the LUTs using model-simulated precipitation properties with those originally simulated by the model. The results of the self-consistency check validate the new classification and LUTs. High latitude retrievals from the new LUTs are merged with those from the CSH algorithm to retrieve LH profiles over the GPM domain using precipitation properties retrieved from the GPM combined algorithm.

Electric compound action potentials (ECAPs) and impedances in an open and closed operative site during cochlear implantation

INTRODUCTION

In patients undergoing cochlear implantation, intraoperative measures of impedance and electrically evoked compound action potentials (ECAPs) are used to confirm device integrity and electrode array position. However, these electrophysiological parameters have been shown to decrease over time, with a small decrement observable as early as 24 h post implantation and becoming more apparent after 6 months. Whether the intraoperatively measured impedances and ECAPs recorded immediately after electrode insertion versus later in the operation or in an open versus closed operative site vary has not been documented. Such variation in measurement procedure may affect the ultimate operative outcome.

PATIENTS AND METHODS

Between February and October 2016, 38 patients received a cochlear implant (Cochlear^®), with half receiving a CI 522 device and the other half receiving a CI 512 device. These patients were distributed into three groups. In the first (group A; n = 21), the impedance and threshold neural response telemetry (tNRT) measures were taken before (M1) and after cutaneous suture (M2), whereas in the second group (group B; n = 11) they were taken twice in the open operative site, once at the time of electrode insertion (M1) and then again 10 min later (M2). The last group (group C; n = 6) was measured only once after a 10 min waiting time before closing the operative site.

RESULTS

tNRTs of both group A and B were significantly higher at M1 than measured at M2. The magnitude of change in tNRT did vary significantly by group (P = .027) with group A having a bigger decrease than group B. For impedances there was evidence for a significant difference in M2 between the three groups (P = .012), with group C having significantly higher values compared to group A and B.

CONCLUSION

Intraoperative tNRT measures change significantly over time, including within the first 10 min of implantation. One underlying etiology of this phenomenon for tNRTs seems to be the condition of the surgical site whereas changes of impedances can be best explained by the 'electrochemical cleaning' theory associated with the first stimulation of the electrode. However, for both impedances and tNRTs there also is an important impact of time as well as of acute perioperative changes in electrical conductivity.