Effects of Virtual Reality on PostOperative WEllbeing and recovery (POWER of VR) in children and adolescents undergoing major surgery: study protocol for a prospective, multicentre randomised controlled trial

Abstract

Introduction

Postoperative pain in children and adolescents is frequently reported, despite numerous advancements in pain management strategies. Virtual reality (VR) is a non-pharmacological tool, which has shown to be effective in reducing acute and procedural pain in children and adolescents. However, there are no studies on VR as an adjunctive treatment of postoperative pain management in the paediatric population. The aim of this study is to evaluate the effectiveness of VR in reducing postoperative pain in children and adolescents undergoing major surgery.

Methods and analysis

This is a multicentre, prospective, unblinded randomised controlled trial conducted in two tertiary academic children’s hospitals in the Netherlands. 159 children and adolescents aged 6–18 undergoing major surgery with expected moderate to severe postoperative pain will be included. Patients will be stratified according to pain treatment and subsequently randomised into two study arms with a 2:1 allocation ratio to receive either (a) VR intervention plus care as usual (CAU) or (b) CAU alone during the first 3 days postoperatively. The primary outcome of this study is the difference between the two intervention groups in rate of change in postoperative pain scores during the first 3 days postoperatively, measured by the Numeric Rating Scale Pain. Secondary outcomes include the immediate- and long-term effects of VR on pain intensity, anxiety, trauma-related symptoms, quality of recovery, opioid and analgesic consumption and incidence of chronic postoperative pain. Analyses will be based on an intention-to-treat approach, employing a linear mixed model to compare the effect of VR to CAU over time. Additional analyses will evaluate usability, user satisfaction, cost-effectiveness and predictors of treatment response.

Ethics and dissemination

The Erasmus MC Medical Ethics Review Committee, Rotterdam, the Netherlands granted ethical approval for this study in July 2025. Results from this study will be published as soon as possible after completed data collection in international peer-reviewed scientific journals.

Clinical trial registration

NL-OMON57871.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• A repeated-measures design as used in this study accounts for temporal variability in postoperative pain by collecting pain scores during the first three postoperative days, thereby capturing individual postoperative pain trajectories over time.

• Rather than focusing solely on postoperative pain, the study incorporates multiple additional patient-reported outcomes, including recovery, anxiety, trauma-related symptoms and sleep quality, reflecting the multidimensional nature of the postoperative experience.

• Due to the pragmatic nature of this randomised controlled trial, the study design allows for personal adaptation of the intervention, enabling patients to tailor timing and duration to their individual needs and preferences, according to their perceived need for support.

• The nature of the intervention prevents blinding of the treatment allocation.

• VR-related adverse effects such as dizziness and nausea may exacerbate postoperative nausea and vomiting, a common side effect following anaesthesia and surgery, potentially limiting adherence to the intervention.

Introduction

Background and rationale

Postoperative pain management is a critical aspect of paediatric surgical care, with significant implications for a child’s recovery, overall well-being and long-term outcomes. Despite numerous advancements in surgical techniques and pain management strategies, many children still experience high levels of pain during hospital stay.^1–3 If acute pain is not treated adequately, patients may develop chronic post-surgical pain (CPSP).⁴ Traditional analgesic techniques, such as administration of opioids, often carry the risk of adverse effects, including respiratory depression, sedation, delayed recovery and risk for addiction.⁵ Moreover, the perioperative period is often marked by heightened anxiety, fear and emotional distress, which can intensify pain perception and negatively impact recovery.⁶ If not handled adequately, this stressful experience may compromise a child’s overall physical and psychological well-being, increasing the risk of developing post-traumatic stress, anxiety and behavioural changes.^{7 8} Consequently, there is a need to explore safe and effective additional therapies that reduce reliance on pharmacological interventions, to optimise postoperative pain management in paediatric patients and enhance their overall postoperative well-being.

Virtual reality (VR) is an innovative, non-pharmacological intervention, increasingly used on paediatric hospital wards. Through immersion in computer-generated environments, VR facilitates distraction and engagement and enhances patients’ sense of control, thereby attenuating attention to painful stimuli and decreasing perceived pain. Recent systematic reviews and meta-analyses demonstrated a significant and clinically relevant effect of VR in reducing pain and anxiety during medical procedures and acute pain such as sickle cell crises in paediatric patients.^9–11

Despite promising findings on the ability of VR to target both the physical and psychological dimensions of pain, robust evidence for its postoperative use in postoperative pain management among paediatric surgical patients is still lacking.¹² Furthermore, predictors for the success of a VR intervention—such as preoperative anxiety and pain coping strategies—have not been adequately explored yet.

There are different types of VR interventions that can be employed to reduce pain and anxiety, the main ones being VR for distraction (VR-D) and VR for relaxation (VR-R).^{13 14} While both types of VR interventions demonstrate potential in alleviating pain and anxiety,^{14 15} further research is needed to delineate their comparative effectiveness and investigate any synergistic effects. Additionally, determining the optimal timing, duration and frequency of VR interventions during the perioperative period should be investigated to establish the most effective protocols for implementation.

We hypothesise that implementing VR as an adjunctive therapy during the postoperative period will alleviate pain immediately and enhance overall quality of recovery, while yielding lasting benefits during postoperative recovery. These improvements include a reduction in stress, anxiety and other behavioural changes associated with the perioperative period.

Objectives

Primary objective

The primary objective of the PostOperative WEllbeing and Recovery (POWER) of VR study is to assess the effectiveness of a VR intervention compared with care as usual (CAU) in reducing postoperative pain in children and adolescents undergoing major surgery.

Secondary objectives

Secondarily, we will compare the immediate and long-term effects of postoperative VR use vs CAU on pain intensity, anxiety and trauma-related symptoms, quality of recovery, opioid and analgesic consumption and the incidence of CPSP. We will also examine whether specific demographic, clinical and psychological characteristics predict the effectiveness of the VR intervention in reducing postoperative pain. Furthermore, we will compare the effects of two VR modalities—VR-D and VR-R—against CAU on postoperative pain reduction. Lastly, this study will evaluate the acceptability, usability, user satisfaction and cost-effectiveness of VR as an adjunctive treatment to CAU.

Methods and analysis

Study design

The POWER of VR study is a national multicentre, prospective, unblinded, pragmatic randomised controlled trial assessing the effectiveness of VR as an adjunctive therapy for reducing postoperative pain in children and adolescents. Children and adolescents aged 6–18 undergoing elective surgery with expected moderate to severe postoperative pain and 2 nights of hospital admission postoperatively will be randomised with a 2:1 allocation ratio to receive either (a) VR intervention+CAU or (b) CAU only. A summary of the study design can be found in figure 1. All patients will be followed up until 3 months post-discharge, irrespective of their randomisation arm.

Figure 1. Schematic display of the study design. This study will be conducted in three phases. Outcome measures will be assessed by questionnaires set out to patients, parents and healthcare professionals. During the first phase (T0), taking place in the preoperative period, questionnaires on predictors of the success of the VR intervention will be collected. During hospital admission (T1–T3), the VR intervention will be administered, and questionnaires evaluating the primary outcome (NRS Pain) and the immediate effects on secondary outcomes will be completed. At 6 weeks (T4) and 3 months (T5) after discharge, secondary outcomes will be reassessed to evaluate the long-term impact of the VR intervention. CAU, care as usual; CPSP, chronic postsurgical pain; NRS Pain, Numeric Rating Scale Pain; VR, virtual reality.

Study settings and recruitment

Participating centres are two tertiary, academic (paediatric) hospitals in the Netherlands (Erasmus MC Sophia Children’s Hospital; Amsterdam University Medical Centre (Amsterdam UMC)). Recruitment began in September 2025, anticipating a total study duration of 2.5 years.

Eligible patients are children and adolescents 6–18 years of age, scheduled to undergo surgery with expected severe to moderate postoperative pain. Physicians at the hospitals will identify potential participants based on surgical eligibility criteria and inform them about POWER of VR study. After expressing interest in participation in the study, informed consent will be obtained by trained members of the research team, according to Dutch legislation.

Inclusion criteria

In order to be eligible to participate in this study, a participant must meet all of the following criteria: (a) 6–18 years old at inclusion; (b) American Society of Anaesthesiologists (ASA) classification status I-III; (c) 2 nights of hospital admission postoperatively; (d) undergoing one of the following surgical procedures: laparotomy, laparoscopy, orthopaedic or trauma surgery, scoliosis surgery, thoracotomy, thoracoscopy or Nuss bar or Ravitch procedure for pectus excavatum; (e) informed consent from patient and/or parents or legal representatives.

Exclusion criteria

A potential participant who meets any of the following criteria will be excluded from participation: (a) developmental delay; (b) admitted to the Intensive Care Unit because of mechanical ventilation or sedation; (c) ASA classification status IV-V; (d) sedated postoperatively; (e) history of epilepsy; (f) severe visual impairment; (g) head wounds; (h) not able to understand or read Dutch (child and/or parents); (i) included in another clinical study in which a participant is subject to the Medical Research involving Human Subjects Act; (j) strict isolation at time of hospital admission.

Informed consent

The informed consent process follows institutional guidelines and ensures sufficient consideration time. Informed consent is remotely and digitally signed through an institutionally verified web-based system. Written informed consent will always be available as an alternative if digital consent is not possible. All parents and children aged 12 years and older must provide written informed consent. Children aged 11 years and younger have to give permission orally.

Randomisation, blinding and treatment allocation

Patients will be randomly assigned with a 2:1 allocation ratio to either the VR intervention group or the CAU-group respectively. Since we will be investigating numerous outcome measures and predictors, as well as the effectiveness of different VR interventions (VR-D vs VR-R) as a secondary objective, allocation is asymmetrical with a larger number of patients assigned to the intervention group. Patients will be stratified according to postoperative pain treatment (epidural/regional or oral/IV opioids) prior to randomisation to ensure balanced distribution across the two treatment arms. Randomisation will be performed through a verified web-based randomisation system with varying block sizes (3 and 6) to minimise the risk of predicting treatment allocation within each stratum.¹⁶ Only members of the research team at the sponsor location have access to the randomisation database. Due to the nature of the intervention and the fact that VR requires instruction, the allocation to the treatment arm will not be blinded to the patients, parents/caregivers, healthcare personnel and the research team.

Study intervention

All patients receive standardised postoperative analgesia and care tailored to the type of surgery. This regimen generally consists of paracetamol, nonsteroidal anti-inflammatory drugs and IV analgesics (such as morphine), regional analgesia techniques (epidural analgesia) and sometimes co-analgesics (such as clonidine or esketamine). All patients, whether or not assigned to the intervention group, are allowed to use a smartphone or tablet as a distraction tool. Healthcare personnel are instructed not to administer VR as part of healthcare to patients enrolled in this study.

Patients assigned to the VR intervention group will receive a VR intervention during the first 3 postoperative days or until discharge (whichever comes first), since postoperative pain is usually highest in the first 3 days postoperatively. To reduce the risk of postoperative nausea and vomiting directly postoperatively, the first VR session is scheduled the day after surgery, as nausea and drowsiness are known side effects of VR (called cybersickness).¹⁷ Patients are able to choose the content of the software themselves (VR-D and VR-R), allowing the intervention to be tailored to the individual. Qualitative findings on patient-reported VR experiences recommend 15 min sessions daily, with optional additional use if desired.¹⁷ A maximum of 45 min per session and a total duration of 2 hours per day is strongly advised in line with recommended national screentime guidelines.¹⁸

This study will use the PICO G3+ headset (Qingdao PICO Technology, China), featuring the Relax and Distract Plus software (SyncVR Medical Holding B.V., the Netherlands). The VR experience will include interactive games, immersive 360° videos and soothing relaxation exercises. Content is carefully selected to be age-appropriate, engaging and non-threatening. The VR headsets are safe, comfortable and appropriate for paediatric use.

Outcome measures

Primary outcome

The primary outcome measure of this study is postoperative pain measured by Numeric Rating Scale (NRS) Pain. NRS Pain scores will be assessed three times daily during the first three postoperative days (T1–T3; table 1). NRS Pain is an 11-point scale from 0 to 10, where 0 represents ‘no pain’ and 10 ‘worst pain ever’. The scale is validated for children 6 years and older, recommended for all types of pain (acute, postoperative, chronic) and is sensitive to change after analgesics are administered with adequate test-retest reliability.^19–21

Table 1. Outcome measurements.

Variables	Measurement	T0	T1	T2	T3	T4	T5
Primary outcome

Pain
Postoperative pain	NRS Pain three times daily		X	X	X
Secondary outcomes

Predictors*
Demographics and clinical characteristics	Sex, age, surgical history, ASA classification, type of surgery, preoperative opioid/analgesics consumption	X
Surgical stress	SSS	X

Pain
Intensity of postoperative pain	NRS Pain highest score & frequency of NRS Pain≥4		X	X	X
Immediate effect of VR-intervention	NRS Pain pre- and post-intervention		X	X	X
Experience with pain	NRS Pain	X
Pain coping style	PCSPed	X
Parental coping style with child’s pain	PCSPar	X
Incidence of CPSP	Frequency of persisting NRS Pain≥4					X	X

Anxiety
State anxiety	VAS Anxiety		X	X	X
State and trait anxiety	STAI/STAIC	X				X	X
Preoperative parental state and trait anxiety	STAI	X

Trauma
Exposure to adverse and potentially traumatic events, long-term PTSS symptoms	CATS	X				X	X

Quality of recovery
Quality of life	EQ-5D-Y-5L	X	X	X	X	X	X
Sleep quality	PROMIS-SD-SF	X	X	X	X	X	X
Mobility postoperatively	Time to ambulation		X	X	X
Time to recovery postoperatively	Time to discharge		X	X	X

Opioid & other analgesic consumption
Need for medication during hospital stay	Administered morphine equivalents		X	X	X
	Duration of the continuous administration of morphine or regional technique		X	X	X
	Number of patients needing rescue analgesia or co-analgesics on top of standard protocol		X	X	X
Need for medication after discharge	Dosage and frequency of opioid/other analgesics use					X	X

Usability, user satisfaction and acceptability
Difference in effectiveness between VR-D and VR-R	Duration and frequency of VR-D and VR-R use		X	X	X
Usability	Frequency of children completing 3×15 min VR use		X	X	X
	VAS adverse reactions		X
User satisfaction	USEQ			X	X
Acceptability	Qualitative interviews with patients assigned to VR- intervention, their parents and members of the medical staff					X	X

T0 takes place during the preoperative period. T1, T2, T3 represent the first three postoperative days during hospital admission. T4 and T5 take place respectively 6 weeks and 3 months post-discharge from the hospital. Color shading is used to differentiate the assessment periods. NRS pain = Numeric Rating Scale pain–; ASA = American Society of Anaesthesiologists; SSS = Surgical Stress Score; VR = Virtual Reality; PCSPed = Pain Coping Scale for Children–; PCSPar = Pain Coping Scale for Parents–; VAS = Visual Analog Scale; STAI = State Trait Anxiety Inventory; STAIC = State Trait Anxiety Inventory Child ; CATS = Child and Adolescent Trauma Screener; EQ-5D-Y-5L = EurQol-5 Dimensions Youth ; PROMIS-SD-SF = Patient Reported Outcomes Measurement Information System – Sleep Disturbances (Short Form); USEQ= User Satisfaction Evaluation Questionnaire. Color shading is used to differentiate the assessment periods.

^*These measurements are part of standard care and will therefore be retrieved from the EHR.

Secondary outcomes

Secondary outcomes (including pain, anxiety, quality of recovery, opioid and analgesics use and usability) will be assessed using standardised questionnaires during hospital admission (T1–T3) to capture the immediate effects of the VR intervention. Follow-up assessments using the same questionnaires, alongside measures on trauma-related symptoms and CPSP, will be conducted at 6 weeks (T4) and 3 months (T5) after discharge, to assess long-term impact of the VR intervention. Demographic, clinical and psychological characteristics will be assessed prior to surgery (T0) to assess the predictive effect for the success of the intervention. The VR headset will automatically record session timing and duration to provide data on usage patterns (T1–T3). An overview of all secondary outcomes and the validated instruments used to assess them is provided in table 1 with additional extensive information in online supplemental material 1.

• Pain intensity will be assessed during hospital admission (T1–T3) by the NRS Pain highest score and the frequency of NRS Pain≥4.^19–21 Pre- and post-intervention NRS Pain scores will be used to evaluate the immediate effect of the VR intervention.

• State anxiety during hospital stay (T1–T3) will be assessed daily by the Visual Analogue Scale (VAS) Anxiety.²² At T4 and T5, the State Trait Anxiety Inventory Child (STAIC)/State Trait Anxiety Inventory (STAI) will be used to evaluate long-term state and trait anxiety.^23–26

• Exposure to adverse and potentially traumatic events and lasting trauma-related symptoms will be assessed after discharge (T4–T5) using the Child and Adolescent Trauma Screener (CATS).²⁷

• Quality of recovery will be assessed during hospital admission and post-discharge (T1–T5) using quality of life and sleep quality questionnaires (respectively; EurQol-5 Dimensions Youth (EQ-5D-Y-5L) and Patient Reported Outcomes Measurement Information System – Sleep Disturbances Short Form (PROMIS-SD-SF)) and by measuring time to ambulation and time to postoperative discharge.^{28 29}

• Opioid and other analgesic consumption will be evaluated through the duration of the continuous administration of either morphine or regional technique, the number of patients needing rescue analgesia or co-analgesics on top of standard protocol analgesics (such as esketamine or clonidine) and morphine equivalents administered to patients during hospital stay (T1–T3). Post-discharge (T4 and T5), parents and children will be asked about the dosage and frequency of analgesic use.

• Incidence of CPSP will be determined by determining the frequency of NRS Pain scores≥4 at T4 and T5.²⁰

• Data on the duration and frequency of the use of VR headsets during hospital admission (T1–T3) will be retrieved from the VR software, to investigate a possible difference in the pain-reducing effect between VR-D and VR-R. These data will be used additionally to give insights into the optimal timing and duration of the use of VR.

• Usability of the VR intervention will be measured by the frequency of children actually completing 3 VR sessions of 15 min (T1–T3), as well as a VAS at T1 to give insight into adverse reactions (dizziness, nausea and headache).

• User satisfaction will be assessed through the User Satisfaction Evaluation Questionnaire (T2–T3).^{30 31}

• Acceptability will be evaluated by conducting qualitative interviews with several patients included in the VR intervention group, their parents and members of the medical staff.

• Cost-effectiveness will be evaluated based on quality of life, time to ambulation, time to postoperative discharge and analgesic use (T1–T3), taking the price of the VR headset and software into account.

• Several patient characteristics will be assessed at T0 to evaluate their predictive value for the pain-reducing effect of the VR intervention. Demographic and patient characteristics will be obtained from the Electronic Health Record, including sex, age, surgical history, ASA classification, type of surgery and preoperative analgesic consumption. Additionally, the severity of surgical stress will be assessed at T1 using the Surgical Stress Score.³² Psychological characteristics will be assessed at T0 using validated questionnaires, including experience with pain (NRS Pain), child’s pain coping style (Pain Coping Scale Child (PCSPed)), parental coping style with their child’s pain (Pain Coping Scale Parents (PCSPar)), child anxiety (VAS/STAIC/STAI), parental anxiety (STAI), trauma-related symptoms (CATS), quality of life (EQ-5D-Y-5L) and sleep quality (PROMIS-SD-SF).^19–31

Statistical analysis

Sample size calculation

The primary analysis will use a linear mixed model (LMM) to assess between-group differences in NRS pain scores over time.

A persisting challenge in clinical research on postoperative pain is the absence of a validated quantification of a minimally clinically important difference (MCID) specific to acute or postoperative pain.^{33 34} Moreover, while the MCID reflects a clinically meaningful change at the individual level, it cannot be extrapolated to detect differences between groups.³⁴ Evidence on VR for postoperative pain in the paediatric population is also scarce, and largely derived from small pilot studies that provide imprecise effect estimates and focus primarily on immediate post-intervention pain scores, leaving longer-term postoperative parameters uncertain.^{12 34 35}

Given the absence of reliable estimates for a formal simulation-based sample size calculation for the LMM, a two-sample comparison of independent means was used as a pragmatic approximation. In absence of reliable empirical estimate of the expected treatment effect, a standardised effect measure of Cohen’s d=0.5 was assumed, corresponding to a medium effect size. This approach was considered a reasonable approximation because the planned LMM efficiently incorporates the repeated measurement data while accounting for within-subject correlations, thereby maximising the information obtained from available data.

Using a standardised Cohen’s d of 0.5, an allocation ratio of 2:1, 80% power, and a 5% significance level, we estimated a required sample size of 144. With an estimated loss to follow-up of 10%, our final sample size consisted of 159 participants (106 in the VR intervention group and 53 in the CAU group).

Analysis plan

Analyses will be based on an intention-to-treat approach. A p value of <0.05 will be considered statistically significant. Continuous data will be presented by mean (SD) or median (inter-quartile range) depending on normality. Categorical data will be presented as proportions.

Analysis plan for primary outcome

An LMM will be employed to compare the effect of treatment on the NRS Pain over time between the VR intervention and CAU groups. NRS Pain measured three times daily at T1, T2 and T3 will be used in our primary analysis. All individual measurements will be included as separate observations in the analysis, rather than being aggregated into a summary measure (eg, daily mean or peak).

Time will be modelled as a continuous variable, with baseline included as time=0, allowing estimation of the trajectory (slope) of pain over the study period. The VR intervention treatment, stratification variable (type of pain treatment) and time along with the interaction term of VR intervention and time will be included as fixed effects. By including this interaction term, we can assess our key parameter of interest, namely whether the rate of change (slope) in pain scores differs between the VR intervention and CAU alone groups. Random intercepts will be incorporated to account for the repeated measures within individual patients, capturing the within-subject correlation. Linear mixed-effects models are well suited for longitudinal data and can appropriately handle unbalanced data arising from missed assessments, while providing valid statistical inference under the missing-at-random assumption.

A statistically significant interaction term (p<0.05) will be interpreted as evidence that the VR intervention modifies the rate of change in pain scores over time differently compared with CAU alone. Additionally, graphical models will be used to visualise the relationship between treatment and NRS Pain improvement, providing a comprehensive understanding of the treatment effects over time.

Analysis plans for secondary outcomes

To explore the association between treatment and secondary outcomes, (generalised) linear (mixed) effect regression models will be employed. The models will include the VR intervention treatment, type of pain treatment and time, along with the interaction term of VR intervention and time, as fixed effects.

Mixed-effects models will be applied for repeated measures outcomes during hospital stay and the follow-up period. Predictors will be included as fixed effects in the model.

To further investigate the effect of different types of VR interventions (VR-D vs VR-R) an extended LMM described in the primary analysis will be used. Type of intervention, duration and postoperative day will be included as fixed effects, since we are expecting these characteristics to influence the effect of the intervention.

Descriptive statistics will be used to summarise acceptability and user satisfaction. Qualitative interviews with individual patients included in the VR intervention and their parents as well as healthcare personnel will be conducted to gain an in-depth understanding of the experience with VR in the hospital.

Cost-effectiveness will be evaluated based on quality of life, time to ambulation, time to postoperative discharge and opioid/other analgesic use, taking the price of VR headset and software into account.

Ethics and dissemination

Ethics

The Erasmus MC Medical Ethics Review Committee, Rotterdam, the Netherlands, granted approval for this study in July 2025 (MEC-2025-0187/NL-009410). All patients and/or their parents/legal guardians will give oral and/or written informed consent (depending on age, according to Dutch regulations) prior to their inclusion in the study. The study was registered at Overview of Medical Research in the Netherlands registry (OMON) and the International Clinical Trial Registry Platform of the WHO (NL-OMON57871) on the 17th of February 2025. This study complies with the principles of the Declaration of Helsinki as amended on the 75th World Medical Association General Assembly in Helsinki (October 2024), and the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use Guideline for Good Clinical Practice.

Safety (adverse event monitoring)

Due to the negligibility of risks for the use of VR, a low occurrence of adverse events (AEs) is expected. Only AEs directly related to the VR intervention, such as nausea or dizziness as a result of VR-use, will be reported. Healthcare personnel will monitor these AEs for the duration of hospital admission.

Data collection, storage and monitoring

Data collection takes place pre- and postoperatively, with daily measurements of NRS Pain scores (three times daily) and secondary outcomes (once daily) during hospital admission until postoperative day 3 or discharge, whichever occurs first. For patients discharged before completing three postoperative days, daily measurements will end at discharge, while follow-up assessments at T4 and T5 will proceed as scheduled.

For a detailed overview of all parameters given, see table 1 and figure 1. For participants who withdraw from the study, all data collected up to the point of withdrawal will be retained and included in analyses.

Data will be stored in an online eCRF compliant with institutional guidelines. Paper records will be kept in a locked cabinet, and all data used for analyses will be pseudonymised through unique numeric codes unrelated to personal identifiers and stored in a key file separate from the database. Access to the full dataset and the key file is restricted to the sponsor-site research team, with other centres limited to their own patient data. De-identifiable participant data, along with the associated statistical code, will be made available via Microsoft Dataverse.

Monitoring of the trial will be performed by an independent certified monitor, according to University Medical Centres Netherlands guidelines.

Dissemination plans

Data from this study will be used for various scientific publications in international peer-reviewed scientific journals. Results will be published as soon as possible after the end of the follow-up period of the last included patient. Additionally, we aim to present results in national and international conferences within the scope of the target group, namely: anaesthesiologists, surgical specialists, paediatricians, paediatric psychologists/psychiatrists and other child-life specialists. Results of this study will be disclosed unreservedly. It is our aim that the results of this study will be implemented through guidelines on the treatment of (acute) postoperative pain in the paediatric population, both internationally and on a local level, by education of health care personnel how to integrate this technology into daily practice. Therefore, medical personnel as well as patient and parent representatives contributed to the study design and will remain involved throughout the study.

Patient and public involvement

A representative of the patient organisation for children and families in medical care, Child & Care Foundation (NL: Stichting Kind & Zorg), contributed to the development of the research protocol.