This study was designed as a monocentric, randomized controlled pilot trial with two parallel intervention groups and a 1:1 allocation. Participants were deemed eligible if they were undergoing the implantation procedure without the use of general anesthesia.

Adult patients undergoing port implantation under LA for any given underlying disease were the target population of the trial. Exclusion criteria were set to ensure patient safety and trial integrity. Individuals were excluded if they had an American Society of Anesthesiologists (ASA) physical status classification > 3. Other exclusion criteria included the presence of chronic pain, cognitive capacity issues prohibiting to follow the VR procedure, uncontrolled epilepsy, auditory or visual disorders, and pre-existing implanted devices (e.g., hearing aids or cardiac pacemakers/defibrillators). Additionally, patients participating in other trials that might interfere with this study’s outcomes or those with significant language barriers that could impede informed consent or understanding of procedure instructions were also excluded.

The sample size had been estimated as sufficient for generating initial efficacy data, enabling a reliable sample size calculation for a subsequent confirmatory trial. This estimation was based on the rules of thumb for sample size estimation in pilot trials as proposed by Whitehead et al. (Whitehead et al. 2016). It was determined that even with a relatively small standardized difference (δ ≤ 0.1), a sample of 50 or more patients per group would suffice to calculate a reliable sample size for a subsequent confirmatory trial with 80% power.

Patients scheduled for elective port implantation for any given indication were assessed for suitability during their outpatient visit. After obtaining consent for the surgical procedure, patients were informed about the trial and were asked for participation. The primary method for port implantation was venae sectio of the cephalic vein. If this was unsuccessful, a modified Seldinger’s technique was used through the cephalic vein. Only when this failed a sonography-guided puncture of the subclavian vein was performed and the port was implanted in Seldinger’s technique as outlined in the PORTAS-3 study (Hüttner et al. 2019). Typically, the port was placed on the patient’s non-dominant side (e.g., left side for right-handed individuals) unless specific factors dictated otherwise. A certified commercial port system was employed with a regular port catheter size of 8 French, or 6.6 French in patients with narrow veins.

In the operating room, the deltopectoral groove area was infiltrated with 20 ml ropivacaine (7.5%) as local anesthetic. Patients received anesthesia stand-by monitoring. If required, supplementary pain medication (such as metamizole or piritramide) or sedatives (like remifentanil, which serves dual roles as a sedative and analgesic or propofol) were administered during the operation depending on individual patient’s request/need and anesthesiologist’s assessment.

Postoperatively, patients were observed for approximately 2 h in the outpatient surgical facility and were usually discharged home thereafter. In case of venous puncture, a post-surgical chest X-ray was carried out in order to exclude a pneumothorax. Monitoring was continued for potential postoperative complications such as surgical site infections or issues related to the port system’s placement or functionality during the follow-up.

For the experimental group, the CE-certified software application HypnoVR (HypnoVR SAS, Lampertheim, France, www.hypnovr.io) together with a commercially available VR headset (PICO G2 4 K All-In-One headset, Pico Technology, Beijing, China) has been used.

Patients had the option to select a VR environment from the following options: “winter magic,” “forest,” “tropical beach,” “deep sea diving,” “space voyage,” and “four seasons.” Additionally, they could pick a musical atmosphere (options included “relaxation,” “serenity,” “lounge,” “symphony,” “soft guitar,” “Asian ambiance”) and an optional additional guiding voice (either male or female) offering breathing directives and immersing them in the narrative. The VR scene was designed to shift gradually, minimizing the risk of inducing motion sickness.

Given the persistent requirement for verbal communication during the procedure, headphones were not employed. Instead, the VR headset’s built-in speakers delivered the musical atmosphere and vocal instructions.

The use of the VR setup aimed to create a calming and immersive environment, potentially reducing patient anxiety and discomfort. The VR experience was designed to be patient-centered, allowing for its discontinuation upon any sign of discomfort or at the patient’s request. Additionally, if patients experienced specific symptoms such as dizziness, nausea, or visual abnormalities, the VR would be immediately halted to ensure patient well-being.

In this investigation, a comprehensive set of baseline and demographic data was collected for every participant, including their birth year, gender identity (female, male, or diverse), height, weight, body mass index, usage of glasses or contact lenses, classification under the American Society of Anesthesiologists system, underlying disease that necessitated port implantation, reasons for the implantation, any history of port implantations along with their count, pertinent comorbidities, and medical history including an assessment using the updated Charlson Comorbidity Index, covering a variety of health conditions (Quan et al. 2011).

Data collection on the day of surgery encompassed the following range of parameters: responses from a preoperative questionnaire and perioperative pain levels ascertained through the numerical rating scale (NRS). Participants completed a survey at three different points: before the operation, right after the operation, and prior to leaving the hospital, approximately 2 h after surgery. This survey gauged the patient’s current pain intensity using a numeric rating scale (NRS), where 0 signifies no pain and 10 represents the most severe pain imaginable. It also incorporated the six-item State-Trait Anxiety Inventory (STAI-6) to evaluate stress and anxiety during the perioperative period. STAI scores are commonly classified as “no or low anxiety” (20–37), “moderate anxiety” (38–44), and “high anxiety” (45–80) (Kayikcioglu et al. 2017; Nigussie et al. 2014).

Beyond the NRS and STAI-6, the pre-discharge survey inquired about symptoms of VR sickness like dizziness, nausea, vomiting, headaches, and fatigue. It also evaluated how patients tolerated the procedure (Likert scale: 1 = highly tolerable–5 = not at all tolerable) and their satisfaction level regarding the operation (Likert scale: 1 = highly satisfied–5 = extremely unsatisfied).

Furthermore, the surgeon’s contentment with the operation was also gauged (Likert scale: 1 = very pleased–5 = extremely displeased).

Other data captured included duration of surgery, the finally chosen technique for implantation, use of sonography-guided puncture, occurrence of any complications during the operation, types and quantities of perioperative analgesia, sedation, and local anesthetic administered, responses from an immediate postoperative questionnaire, time of patient discharge, the period from the end of surgery to discharge, a questionnaire completed prior to discharge, and any complications that arose postoperatively until the time of discharge.

The study meticulously documented and classified postoperative complications according to the Clavien-Dindo system (Dindo et al. 2004). The types of complications monitored included surgical site infections, incidents of postoperative bleeding or hematoma, thrombosis, cases of pneumothorax or hemothorax, issues with the port system such as dislocation or malfunction, catheter-related sepsis, and occurrences of nerve palsy.

For those patients assigned to the intervention group, information about their prior experiences with virtual reality (VR) was recorded. Further details noted included the chosen VR scenario, the hypnotic voice and musical background used, and whether the VR procedure was terminated prematurely, before the end of surgery.

Finally, a follow-up was conducted on the 30th day after the operation, wherein patients were contacted via telephone to evaluate any postoperative complications that might have developed following their discharge.

Randomization was performed preoperatively using the REDCap (Research Electronic Data Capture) randomization module, either 1 day before or on the day of surgery. The randomization module is fully integrated within the REDCap system, meaning researchers can seamlessly randomize participants based on data already entered into REDCap, ensuring consistency and efficiency in the study process. The module automates the process of random assignment of participants into different study arms. This automation ensures that the randomization process is unbiased and adheres to the predetermined allocation ratio (Harris et al. 2009). A computer-generated, balanced permuted block randomization sequence was used for randomization.