Virtual reality for pain relief during office hysteroscopy: a randomized controlled trial

Abstract

Objective

Office hysteroscopy (OH) is widely used to diagnose and manage intrauterine pathologies. However, pain remains the primary factor that contributes to OH failure. This study aimed to assess the effect of virtual reality (VR) on pain reduction during OH.

Methods

A prospective randomized controlled clinical trial was conducted at a university hospital between July and November 2024. The study involved 50 women undergoing OH randomly allocated to receive immersive VR videos during the procedure or standard care. The main outcome measure was self-reported intraoperative pain evaluated using a numerical rating scale. Other measures included satisfaction, duration, and success of the procedure.

Results

Mean pain scores were 6.16±1.86 in standard care group and 4.88±1.69 in VR group (difference, 1.28; 95% confidence interval [CI], 0.27 to 2.29; P=0.014). After adjusting for other variables, no statistically significant relationship was found between VR and severe pain (odds ratio, 0.75; 95% CI, 0.15 to 3.87; P=0.73); only severe anxiety in women and procedure duration were associated with severe pain.

Conclusion

Virtual reality did not significantly reduce pain severity during hysteroscopy. However, severe pain was associated with high anxiety and a longer procedure duration. These findings suggest that VR may not effectively mitigate severe pain, whereas managing anxiety and minimizing procedure time could be more effective strategies.

Introduction

Office hysteroscopy (OH) is a minimally invasive, safe, and effective intervention for the diagnosis and treatment of several intrauterine and endocervical pathologies [1]. Direct visualization of the uterine cavity outside the operating theater, without anesthesia, is a cost-effective approach associated with improved physician and patient satisfaction [2].

Newer technologies, such as smaller cameras, improved tissue removal devices, and recommendations for pain control, have enhanced the comfort of OH for both physicians and patients [3].

Pain perception varies among individuals in terms of the nature, severity, duration, and intensity of discomfort. It is a complex process that extends beyond the type and scope of tissue damage [4].

Pain and discomfort during OH are typically related to cervical manipulation, uterine cavity distension, peritoneal spilling of the distension medium, and stimulation of myometrically sensitive fibers [5]. Predictors of pain perception during OH include hysteroscope diameter, unfavorable cervical canal features, parity, menopausal status, anxiety, procedure duration, and surgeon experience [5,6]. Anxiety was found to be the most common cause of OH failure, as it increases pain perception, decreases tolerability of the procedure, and reduces patient compliance, challenging the use of OH [7].

Virtual reality (VR) is a recently developed technique used for pain distraction that provides a computer-generated immersive environment viewed through a headset. This technique has become an appealing option for alleviating pain and providing cognitive distraction during medical procedures, particularly with recent reductions in costs and advancements in the quality and accessibility of VR devices [8]. Available data on VR effectiveness in reducing anxiety levels and pain perception during OH are inconclusive [9,10]. This study aimed to evaluate the effect of VR on pain severity in women who underwent OH.

Materials and methods

This open-label, prospective, randomized controlled trial was conducted at a single tertiary university hospital from July to November 2024. Fifty women aged 18–60 years, scheduled for diagnostic hysteroscopy, participated in the study. Women with acute pelvic infections, heavy uterine bleeding, or pregnancy were excluded from the study. Women with psychological, hearing, or visual disorders, and those with anatomical conditions that could complicate OH, such as cervical stenosis, fibrosis, or cervical amputation, were excluded. Women scheduled for operative hysteroscopy and those with a history of failed hysteroscopy were also excluded.

All participants underwent a comprehensive history-taking and examination. Eligible women were randomly assigned to either the control or the VR group using sealed envelopes, based on pre-generated randomization sequences from a computerized random number generator. Given the nature of the intervention, blinding of the participants, healthcare providers, and outcome assessors was not feasible; however, the allocation remained concealed until the randomization process was completed.

Prior to participant recruitment, all women were shown the VR and allowed to try it on, but no content was viewed as the video played only at the start of the procedure. They were prescribed 1 g of paracetamol orally 1 hour before the procedure and assessed for anxiety, which was recorded using a 3-point Likert scale (mild, moderate, and severe anxiety). During diagnostic hysteroscopic examination, participants were placed in the lithotomy position. The examination was performed using the vaginoscopic approach without a tenaculum or cervical dilatation, using a 4-mm continuous-flow office hysteroscope (“size 4” Karl Storz, Tuttlingen, Germany) with a 2.9-mm rod lens optic, and without anesthesia. A saline solution was used as the distension medium, which was automatically controlled by an irrigation-suction electronic device (Endomat; Karl Storz) under a preset pressure of 45 mmHg.

In the VR group, the women were fitted with a headset and watched immersive video content. The relaxation experience included viewing a 6-minute video (Virtual Nature 360) simulating a calming nature journey to waterfalls and beaches, which could be explored using the head tracker. The video played continuously throughout the procedure, and participants were allowed to stop the simulation or remove the headset at any point.

The main outcome measure was intraoperative patient-reported pain, assessed using the numeric rating scale, an 11-point scale with the following scoring system: 0, no pain; 1–3, mild pain; 4–6, moderate pain; and 7–10, severe pain. Secondary outcomes included patient satisfaction, categorized as either satisfied or not satisfied. Additional secondary measures included the perception of clinicians and nursing staff regarding the feasibility of utilizing VR equipment for each patient, procedure duration, procedure success, and any reported side effects associated with VR intervention.

1. Ethics approval and consent to participate

The study was approved by the Ethics and Research Committee of the Council of the Department of Obstetrics and Gynecology and the Faculty of Ethics Research Committee (IRB: 157/2024). Written informed consent was obtained from each participant after the principal investigator explained the purpose and procedures of the study. The trial was registered in the clinical registry on May 11, 2024.

2. Statistical methods

An earlier study [11] showed that among patients underwent outpatients hysteroscopy, the average pain score in those received standard care only was higher than those received VR intervention (6.0±2.62 vs. 3.7±2.66, respectively); a sample size of at least 50 patients undergoing outpatients diagnostic hysteroscopy fulfil the inclusion and exclusion criteria divided randomly into two groups (25 patients in each group) will achieve 80% power, at significance level 0.05, using a two-sided two-sample unequal-variance t-test, by using Power Analysis and Sample Size Software PASS 15 version 15.0.10 (NCSS, Kaysville, UT, USA) for sample size calculation.

3. Statistical analysis

Analyses were performed using SPSS for Windows version 20.0 (IBM Corp., Armonk, NY, USA) and MedCalc^© version 18.2.1 (MedCalc^© Software Bvba, Ostend, Belgium). Data were presented as means and standard deviations for numeric parametric variables, medians and interquartile ranges for numeric nonparametric variables, or frequencies and percentages for categorical variables. Normality was tested using the Shapiro-Wilk test. Since no participants withdrew or deviated from the assigned interventions, the intention-to-treat and per-protocol results were identical. Differences between two independent groups were analyzed using the independent Student’s t-test or Mann-Whitney U-test for continuous variables, depending on normality, and the chi-square test or Fisher’s exact test for categorical variables. Univariate and multivariate logistic regression analyses were used to examine the relationship between VR and the occurrence of severe pain during OH after adjusting for the effects of potential confounders. Variables that showed (P<0.25) in the univariate analysis were included in the multivariate analysis [12]. Multiple linear regression analysis was used to analyze the effects of VR use, patient characteristics, and procedure duration on the pain scores. Statistical significance was defined as a two-sided P-value of <0.05.

Results

During the study period between July and November 2024, 62 patients were assessed for eligibility. In accordance with the inclusion criteria, three women were excluded from the study: two had previous cervical surgeries and one had a significant hearing impairment. Additionally, nine women declined to participate in the study. Consequently, the study included 50 women. The recruitment process and management of the study population throughout the study are illustrated in the flow diagram, conforming to the Consolidated Standards of Reporting Trials guidelines (Fig. 1).

Fig. 1.

CONSORT guideline flowchart of participant selection for the study: 62 women were initially assessed, but only 50 met the study criteria. CONSORT, Consolidated Standards of Reporting Trials.

There were no statistically significant differences between the two groups in terms of baseline demographics, clinical characteristics, or indications for hysteroscopy. The mean pain scores on the numerical scale showed a significant difference between the two groups, with the standard care group reporting a mean score of 6.16±1.86 and the VR group reporting a mean score of 4.88±1.69, yielding a P-value of 0.014 (Tables 1, 2).

Table 1.

Baseline demographic and clinical characteristics of standard care and virtual reality groups used in the study

	Standard care (n=25)	Virtual reality (n=25)	P-value	Difference	95% CI	OR (95% CI)
Age (yr)	41 (36–48)	44 (29–54)	0.627	3.0	0.62 to 0.64
Parity
Nulliparous	4 (16.0)	5 (20.0)	0.713	4.0	−17.72 to 25.40	1.31 (0.31 to 5.60)
Parous	21 (84.0)	20 (80.0)
Previous abortions	10 (40.0)	10 (40.0)	1.00	0.0	−25.42 to 25.42	1.0 (0.32 to 3.10)
Number of previous abortions	1.5 (1–2)	2 (1–5)	0.666	0.5	0.296 to 0.314
Previous vaginal deliveries	13 (52.0)	12 (48.0)	0.777	4.0	−22.16 to 29.41	1.18 (0.39 to 3.56)
Number of previous cesarean sections	2 (1–4)	1.5 (1–4)	0.378	0.5	0.64 to 0.66
Menopausal state
Premenopausal	21 (84.0)	18 (72.0)	0.306	12.0	−11.15 to 33.80	2.04 (0.51 to 8.12)
Postmenopausal	4 (16.0)	7 (28.0)
Prior office hysteroscopy	1 (4.0)	1 (4.0)	1.00	0.0	−15.88 to 15.88	1.0 (0.06 to 16.93)
Indication of hysteroscopy
Infertility	5 (20.0)	6 (24.0)	0.253		0.25 to 0.27
Abnormal uterine bleeding	13 (52.0)	5 (20.0)
Missed IUD threads	2 (8.0)	2 (8.0)
Postmenstrual spotting	1 (4.0)	2 (8.0)
RPL	0 (0.0)	2 (8.0)
Postmenopausal bleeding	4 (16.0)	7 (28.0)
Postcoital bleeding	0 (0.0)	1 (4.0)
Anxiety scoring			0.226		0.25 to 0.27
Mild	6 (24.0)	10 (40.0)
Moderate	10 (40.0)	11 (44.0)
Severe	9 (36.0)	4 (16.0)

Values are presented as median (interquartile range) or number (%) unless otherwise indicated.

CI, confidence interval; OR, odds ratio; IUD, intra-uterine device; RPL, recurrent pregnancy loss.

Table 2.

Pain and other procedure outcomes from the standard care and virtual reality groups used in the study

	Standard care (n=25)	Virtual reality (n=25)	P-value	Difference	95% CI	OR (95% CI)
Pain score	6.16±1.86	4.88±1.69	0.014b	1.28	0.27 to 2.29
Pain score grading
Mild to moderate	14 (56.0)	20 (80.0)	0.69c	24.0	−1.82 to 45.97	0.32 (0.09 to 1.12)
Severe	11 (44.0)	5 (20.0)
Patient satisfaction
Satisfied	14 (56.0)	20 (80.0)	0.069c	24.0	−1.82 to 45.97	0.32 (0.09 to 1.12)
Not satisfied	11 (44.0)	5 (20.0)
Duration of hysteroscopy (minutes)	4.5 (4.0–5.5)	4 (3.5–5.0)	0.023a	0.5	0.02 to 0.02
Feasibility of VR	18 (72.0)
Failed hysteroscopy	3 (12.0)	0 (0.0)	0.235d	12.0	−3.45 to 29.96	0.126 (0.01 to 2.58)

Values are presented as mean±standard deviation, number (%), or median (interquartile range) unless otherwise indicated.

CI, confidence interval; OR, odds ratio; VR, virtual reality.

^aMann-Whitney U-test.

^bStudent t-test.

^cChi-squared test.

^dFisher’s exact test.

There were no differences in participant satisfaction or pain grades between the two groups. However, the VR group had a shorter procedure duration with P=0.023. (Table 2)

After adjustment for the effect of potential confounding variables, there was no statistically significant relation between VR and severe pain (odds ratio [OR], 0.75; 95% confidence interval [CI], 0.15 to 3.87; P=0.73). However, severe anxiety and hysteroscopy duration were the only independent predictors of severe pain with (OR, 10.35; 95% CI, 1.74 to 61.51; P=0.010) and (OR, 5.95; 95% CI, 1.71 to 20.68; P=0.005), respectively (Table 3).

Table 3.

Univariate and multivariate regression analysis for possible variables associated with severe pain

	Univariate		Multivariate
	OR (95% CI)	P-value	OR (95% CI)	P-value
Virtual reality use, ref. standard care	0.32 (0.09 to 1.12)	0.075	0.75 (0.15 to 3.87)	0.734
Age (yr)	0.99 (0.95 to 1.05)	0.899
Parity, ref. nulliparous	0.93 (0.20 to 4.31)	0.925
Previous vaginal deliveries, yes	1.45 (0.44 to 4.78)	0.545
Menopausal state, yes	1.33 (0.30 to 5.88)	0.704
Severe anxiety, ref. mild to moderate	9.64 (2.29 to 40.56)	0.002	10.35 (1.74 to 61.51)	0.010
Hysteroscopy duration (minutes)	4.99 (1.89 to 13.17)	0.001	5.95 (1.71 to 20.68)	0.005

All variables in the table were individually included in univariate analysis, and only variables with P<0.25 were included in multivariate analysis.

OR, odds ratio; CI, confidence interval; ref., reference.

Multiple linear regression analysis for potential confounding variables that affect mean pain scores revealed a statistically significant relationship between both severe anxiety and the duration of hysteroscopy and mean pain scores (P=0.001; 95% CI, −2.83 to −0.77; and P=0.002; 95% CI, 0.32 to 1.31), respectively (Table 4).

Table 4.

A multiple linear regression analysis of the effect of virtual reality use, patient characteristics, and procedure duration on pain scores during hysteroscopy

	Beta coefficient (95% CI)	P-value
Virtual reality use, ref. standard care	0.13 (−0.37 to 1.34)	0.256
Age (yr)	0.14 (−0.04 to 0.09)	0.493
Parity, ref. nulliparous	0.07 (−0.82 to 1.51)	0.557
Previous vaginal deliveries, yes	−0.31 (−2.43 to 0.11)	0.071
Menopausal state, yes	0.00 (−1.46 to 1.46)	0.998
Severe anxiety, ref. mild to moderate	−0.43 (−2.83 to −0.77)	0.001
Hysteroscopy duration (minutes)	0.41 (0.32 to 1.31)	0.002

All variables listed in the table were included simultaneously.

CI, confidence interval; ref., reference.

VR technology proved to be a safe method, with no dizziness, nausea, or feelings of claustrophobia reported by women in the intervention group.

Discussion

VR is an imaginative and interactive 3D virtual environment that distracts individuals from external stimuli and promotes positive thinking [10]. We found a significantly greater reduction in mean pain scores in the VR group than in the control group; however, after adjusting for other variables, VR was not significantly associated with mean pain scores or severe pain scores. Our analysis confirmed that severe pain was independently associated with pre-procedural severe anxiety (OR, 10.35; 95% CI, 1.74 to 61.51; P=0.010) and longer procedure duration (OR, 5.95; 95% CI, 1.71 to 20.68; P=0.005).

The effects of VR on pain and anxiety during hysteroscopy remain inconsistent across studies. While one study reported significant reductions in pain (28% for average pain and 38% for worst pain) and anxiety (39%) with VR use [11], our findings align with other studies that showed no significant pain relief [13–15]. Sewell et al. [13] observed reduced anxiety but unchanged pain scores, whereas Fouks et al. [15] found no differences in pain or physiological stress markers.

Objective measures of pain and anxiety, such as heart rate (HR) and respiratory rate, have yielded conflicting results, with one study paradoxically suggesting that VR may increase HR [14,15].

Differences between studies could be explained by the different types of VR software and delivery devices, as more immersive software is more effective in increasing patient distraction during the procedure [13]. The implementation of passive VR, as in our study, where the patient has no control over their experience, may influence the degree of distraction from the surrounding environment. This reduced cognitive engagement could explain the lack of effect on anxiety levels observed in our findings.

Several participant and procedural factors may explain the inconsistent findings across studies, including variations in baseline anxiety levels and individual pain thresholds, cultural and psychological influences on pain perception, and differences in analgesic protocols.

Procedure-related variables, such as hysteroscopy type (diagnostic versus operative), duration, instrument size, cervical dilation requirements, pressure used to distend the uterus, and operator experience, also contributed to outcome variability.

Pain perception has been associated with an increasing state of anxiety, as pain perception is regulated by trait anxiety, which acts physiologically to increase pain through adrenergic response activation [16]. We examined the factors associated with severe pain, identifying that patient anxiety and procedure duration were the only variables significantly correlated with severe pain. To minimize potential bias, the study was restricted to women with no history of hysteroscopic failure or cervical surgery. All participants received the same type and dosage of analgesia administered by the principal investigators 1 hour prior to the procedure. Additionally, all vaginoscopic hysteroscopic procedures were performed by surgeons with more than 5 years of experience using a consistent hysteroscope diameter and maintaining uniform pressure throughout the procedures.

Furthermore, pain assessment was conducted immediately postoperatively to prevent any delayed onset of pain caused by prostaglandin release and prior to performing other procedures, such as endometrial biopsy.

High preoperative anxiety negatively impacts pain perception during and after OH. Anxiety is often driven by fear of the office procedure, concerns about a potential underlying pathology, and long waiting times. The use of validated anxiety assessment tools helps identify at-risk patients, allowing tailored interventions. If anxiety is severe, delaying the procedure, offering detailed counseling, and ensuring patient readiness are advised [5].

Most of our participants reported moderate-to-severe anxiety levels, which could be explained by a lack of health education, as most patients were neither oriented nor familiar with the procedure.

A recent study showed that adequate information and counseling related to the OH procedure effectively reduced pain and anxiety scores and that their role should be increasingly acknowledged [17].

VR technology plays a role in providing information and health education about the procedure to increase familiarity with instruments and maneuvers, which can serve as a triage before being used as a pain relief intervention [11].

Although the use of educational VR videos was reported to provide helpful information to the majority of patients, it did not reduce pre-procedural anxiety levels [18].

Three failed procedures were attributed to difficulties in navigating the cervical canal. The pain scores reported by the three women were 10, 10, and 8. Three women experienced severe anxiety and were completely dissatisfied with the procedures. Notably, all the patients were premenopausal and had a history of multiple cesarean sections.

Other non-pharmacological measures were evaluated to reduce anxiety and pain perception, including intraoperative music as another cognitive distraction measure that distracts the patient’s attention from painful stimuli and focuses on the relaxing state of music [16]. This effect is likely linked to a reduction in the activation of the sympathetic nervous system, causing a state of greater relaxation; however, different studies have shown conflicting results [19]. One study demonstrated a notable reduction in pain perception, although no major changes in other physiological indicators of pain were observed [20]. Another study indicated that patients exposed to music experienced significantly lower anxiety post-procedure and reduced pain during hysteroscopy [21].

A plausible pathophysiological rationale for exploring non-pharmacological pain management strategies is the Gate control theory of pain [22]. For instance, humor, visualization of pleasant scenarios, and musical engagement can attenuate pain perception by partially suppressing nociceptive signals transmitted via slower nerve fibers, owing to overriding stimuli carried by faster-conducting neural pathways [23].

The Royal College of Obstetricians of UK and Gynecologists suggested that both music and VR may be used to reduce the pain and/or anxiety associated with OH, only after ensuring that they do not affect communication with healthcare staff [24].

In conclusion, VR did not significantly reduce severe pain during hysteroscopy, suggesting that it should not replace conventional pain management during hysteroscopy. Addressing pre-procedural anxiety and optimizing procedural efficiency and duration may offer more reliable benefits for pain control.

A notable merit of this study lies in its design as a randomized controlled trial, incorporating several measures to reduce bias, such as VR video standardization, analgesic use, hysteroscope size, and distention medium pressure.

The limitations of this study are worth highlighting. First, this was a single-center study with a small sample size; however, despite the small number of women included in each group, both groups were comparable in terms of age, parity, menopausal state, and all procedures were performed by expert microscopic surgeons. Furthermore, the lack of baseline pain score assessment and patient health education regarding the planned procedure were major drawbacks of our study. Therefore, it would be beneficial to assess different pain expectation scores prior to OH in future studies.