Effectiveness of Virtual Reality Environment for Post-Operative Pain Management

Introduction

As per International Association for the Study of Pain (IASP), pain is defined as ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage’.^[1] Medical or surgical procedures often induce pain and emotional distress for which suitable pharmacological approaches are employed for pain alleviation.^[2] However, these pose the risk of adverse side effects, narrow therapeutic windows and the potential for drug misuse. A shift to newer and safer therapeutic modalities as an adjuvant for pain management is the need of the hour. In view of multidimensional nature of pain, non-pharmacological interventions might have scope for therapeutic potential in the growing epidemic of non-steroidal anti-inflammatory drugs (NSAID) and opioids prescriptions, as they allow manipulation of affective or attentional processes.^[3]

The gold standard to assess the efficacy of pain management after surgery is the patient’s self-assessment of pain.^[4] The characteristic of pain may influence the clinical and psychological outcomes. Hence, continual evaluation of pre- and post-operative pain shall help to deliver an effective patient care and achieve higher patient satisfaction. Variables such as age, coping skills, anxiety and depression may influence levels of post-operative pain.

Virtual reality (VR) has emerged as an effective non-pharmacological therapeutic modality for pain.^[5] VR creates a sensation of a realistic 3D-world utilizing computer-generated images and sound, enabling the users to experience the total immersion in a virtual world. The technologically created virtual milieu with multisensory inputs like vision, audition, and proprioception demand more conscious attention by the cortical areas, which are likely to interfere mutually, resulting in less focus on nociceptive inputs.^[6] Thus, VR acts as a positive distraction limiting the processing of nociceptive stimuli, eventually mitigating subjective pain experience.^[3,7]

Inadequate pain relief remains a major healthcare dilemma despite the advent of multi-modal approaches and updates in clinical practice guidelines. It is often associated with extended hospitalization, increased morbidity and risk of progression into chronic pain.^[8] Targeting physiological and emotional responses to pain shall enhance cognitive reconstruction and pain acceptance.

OBJECTIVE

The aim of the study was to evaluate the efficacy of VR as an adjunct for post-operative pain management in patients undergoing surgical procedures.

• 1.

  Primary objective

  • a.

    To assess the effect of VR intervention on post-operative pain intensity compared to standard therapy alone as measured by Numerical Rating scale (NRS) scores.

• 2.

  Secondary objectives

  • a.

    To evaluate the level of presence and immersion experienced by participants during VR sessions using the I-group Presence Questionnaire (IPQ).

  • b.

    To determine the demographic characteristics of participants.

  • c.

    To examine the clinical course of participants, including the type of surgery, days of hospitalization, and details of pharmacotherapy for analgesia.

  • d.

    To estimate the adverse events and unintended events associated with VR-intervention.

MATERIAL and methods

This was a hospital-based parallel-group randomized controlled study conducted for a period of 2 months from 1 August 2022 to 30 September 2022. The study was initiated after acquiring approval from the Institutional Ethical Committee reference no: GVPIHCMT/IEC/20220620/01 dated 20.06.2022. The study was performed according to the Declarations of Helsinki and Good Clinical practice requirements.

Data collection

The selected patients as per Consolidated Standards of Reporting Trials (CONSORT) guidelines [Figure 1] were subjected to face-to-face interviews and clinical examination. The socio-demographic data included age, gender, marital status, educational qualification, medical history, drug history, family history and history of substance abuse. The clinical information included diagnosis, type, and name of surgery, type of anesthesia given, pharmacotherapy given and route of administration, and number of days of hospitalization.

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Figure 1:

Flowchart of participants for the study as per CONSORT guidelines showing recruitment and progress of the study VRISE: VR-induced symptoms and effects. Control group: receiving standard care post-operatively. Interventional group: receiving VR-based intervention in addition to standard care treatment post-operatively; VR: Virtual reality; CONSORT: Consolidated Standards of Reporting Trials; n: number of participants.

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VR intervention

Each session constituted 15 minutes’ exposure to immersive virtual environment. The VR immersion was achieved with the use of VR headset (Procus Pro, compatible with all smartphones) as shown in Figure 2. The headset had inbuilt headphones for immersive wholesome sound experience. It had provision for focal length adjustment and high-quality lenses providing 100–120 degree field of vision.

The first session was given pre-operatively a day prior to surgery for the patient to get introduced to VR sessions and address any queries. On the day of surgery, in the recovery room, the anesthetic doctor assessed the patient for recovery from anesthetic in terms of regain of consciousness, recovery of protective airway reflexes, and resumption of motor activity. After about 60–90 minutes, when the patient regained his/her coordination of activities and intellectual function and was hemodynamically stable, he/she was shifted to the ward. The patient was subjected to a second VR session approximately 4–6 hours post-operatively. The third session was on the next consecutive day.

The patient was instructed to lie comfortably on the bed and fitted with the VR headset as shown in Figure 2. He/she was asked to select a VR programme of nature scenes with guided relaxation, adjusted to his/her preferences and needs. He/she was encouraged to explore the VR environment, interact with the elements and focus on the sensations and emotions. Simultaneously continuous monitoring was done to look for VRISE or unintended effects under supervision of an attending physician/nurse. At the end of the session, the patients were gently brought back to reality and asked to rate their pain level based on NRS. They were also administered IPQ questionnaire at the end of the VR sessions to evaluate their experience and satisfaction with the VR exposure.

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Figure 2:

VR session of study participant with VR headset; VR: Virtual reality.

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Results

A total of 63 patients who were supposed to undergo surgery were enrolled for the study after taking into consideration the inclusion and exclusion criteria. However, seven patients were excluded due to the reasons cited in Figure 1. A total of 56 patients were assigned into two groups, namely, the control group (standard therapy) and the interventional group (standard therapy + VR), using block randomization method, with 28 patients in each group. In the control group, three patients were excluded as their hospitalization extended beyond three days. In the interventional group, three patients were excluded as they reported VRISE during the VR session. Hence, the data analysis for both groups was limited to 25 patients each [Figure 1].

The mean age of the participants in the control and intervention groups were 36.24 ± 13.01 and 39.56 ± 14.27 years, respectively, with no statistical difference [Table 1]. There was no statistical variation noted regarding gender. Hence, both the control and interventional groups were age and gender-matched.

In the control group and the interventional group, 28% (n = 7) and 72% (n = 18) patients underwent laparoscopic and open surgery, respectively [Table 2]. The average duration of hospitalization in the control and interventional groups was 2.84 ± 0.37 and 2.6 ± 0.645, days, respectively, with no statistical difference. The combination of paracetamol with diclofenac was highest prescribed in both groups for post-operative analgesia with no significant differences. The interventional group had lesser need for rescue analgesic drugs post-operatively as compared to the control group, but it was not statistically significant.

Bupivacaine was the most preferred drug for anesthesia in both groups followed by ropivacaine [Table 3]. The preferred route of administration was spinal. In both the control as shown in Table 4 group utilization and the interventional group as shown in Table 5, paracetamol was the highest prescribed drug followed by diclofenac for post-operative pain management.

The NRS scores in the control and interventional groups during standard post-operative analgesic therapy were not statistically significant (p = 0.3277) [Table 6]. After the VR intervention, the NRS scores on day 1 and day 2 were 6.36 ± 0.95 and 4.2 ± 0.577, respectively [Table 7]. The scores in the interventional group after the VR session were statistically significantly lower as compared to before the VR session (p < 0.001), thus reflecting reduction in pain perception after the VR session. Regarding the experience about the VR session via IPQ, the majority responded positively to the VR experiences, feeling the presence of virtual world, with the virtual world seeming real [Table 8]. For the dichotomous question regarding willingness to undergo VR sessions in hospital care, 80% of the patients gave a positive response.

Discussion

Each patient has his/her unique perception of pain which permits the utilization of a combination of interventions for pain alleviation. Effective management of post-operative pain is considered as the essential and humanitarian requirement of every surgical event.^[13] Post-operative pain management is critical due to its pervasive nature and multi-dimensional components. This has led to the escalation of analgesics prescriptions with the risk of side-effects and addiction. Uncontrolled pain or inadequate pain relief often results in patient’s dissatisfaction.^[8]

In the present study, bupivacaine was the preferred anesthetic drug for surgery given in both groups. After the administration of bupivacaine, pain is the first sensation to be lost. It has prolonged anesthetic action with better sensory than motor block.^[14] The present study also revealed that the combination of paracetamol with diclofenac (NSAID) was the preferred pharmacotherapy for post-operative analgesia among both groups. Ong CKS and his colleagues in their qualitative systematic review of 21 studies highlighted that the combination of NSAIDs with paracetamol showed better improvement in pain relief as compared to the drugs when used alone.^[15] In the post-operative period, the patient is kept nil by mouth that limits its oral usage. Availability of the IV form of paracetamol and its better safety profile has led to increased use of paracetamol in post-operative analgesia.^[16]

In the present study, NRS was used to assess the pain perception in the post-operative phase. The NRS scores, when both groups were on standard pharmacological analgesic therapy, did not show any statistically significant difference. However, after exposure to the VR session in the interventional group, the post-session NRS scores were statistically significantly lower as compared to the pre-session scores. Thus, it could be concluded that the VR intervention caused substantial reduction in pain perception. The findings were consistent with the studies by Payne O et al.,^[17] Karaveli CS et al.,^[18] Jie D et al.^[19] and McSherry T et al.^[20] All the studies have shown a promising potential of VR interventions to redefine non-pharmacological intervention for acute pain services. Higher patient load with limited medical personnel and resources highlights the need for co-existing, user-friendly adjuncts to the standard pharmacological therapy. VR can offer great benefit, especially in the case of children, elderly and obese patients where pain dynamics are unpredictable, and risk of side-effects is higher.^[21–24]

In the present study, three patients showed VRISE during VR sessions, namely, nausea and headache, hence VR sessions were terminated in those patients. Hence, it is essential to watch for VRISE for safer implication of VR in clinical practice.^[25] The possibility of VRISE during any session depends on VR head-mounted display, sound, navigation, ergonomic interaction and user experience. A technological review and meta-analysis of 44 neuroscientific or neuropsychological studies had highlighted the role of technology competency and implementation along with health and safety standards to reduce adverse symptomatology and dropouts.^[26]

In the present study, IQP was used in the interventional group to estimate the feasibility and satisfaction of the VR session. Majority of the participants confirmed that the virtual world seemed real, and they were unaware of the real environment. Majority felt captivated by the VR session and reported lower NRS scores after a VR session. VR interfered with pain perception as the audio-visual inputs provided adequate distraction from pain, thus reducing pain perception.^[7] Hospitalized patients often experience isolation, anxiety, boredom and emotional stress, which can exacerbate their pain perception.^[8] Hence, clinicians should not only rely on physical outcomes but also consider psychosocial endpoints during pain management.

In the present study, 80% of the patients confirmed their willingness to undergo VR sessions as part of hospital care. The findings are similar to the study by McSherry T et al., in which 75% of participants showed willingness to use immersive VR session during wound dressing procedures.^[20] Lesser pain perception shall motivate the patient to adhere to treatment protocols in the post-operative period. It is especially important in cases where mobilization is required to reduce post-operative complications. Better patient satisfaction and better functional status shall lead to shorter hospital stay and reduced hospital expenditure. A similar finding was observed in a study by Cacau LA et al., in which VR was used for post-operative rehabilitation of 60 patients with cardiac surgeries.^[27]

The routine post-operative pain relief embraces the clock regimen of opioid or non-opioid analgesics.^[3] Transforming the post-operative pain-care from the analgesics domain to a comprehensive model requires collaborative efforts. With the advent of safer technologically driven modalities, VR has the potential to open the door against the escalating analgesics prescription that carries the risk of side-effects and drug dependency. VR has good prospects to change dynamics in pain management with respect to change in preferences and demands in health care, especially pain services.

Conclusion

In the present study, the combination of paracetamol and diclofenac (NSAID) was the highest prescribed for post-operative analgesia to both groups. In the interventional group, the NRS scores showed a significant reduction after the VR session as compared to the pre-session scores. Also, majority of patients expressed their satisfaction in the VR session in terms of its relation and engagement. Majority expressed their willingness to undergo VR sessions in future. Thus, VR confers a clinical window for pain alleviation in post-operative patients.

Acknowledgement

The present study was undertaken as the ICMR short-term studentship project in the year 2022, Reference no: 2022-08454.

We express our heartfelt gratitude to the participants who displayed immense interest and co-operation during the study. We are also thankful to the Department of Surgery, Department of Obstetrics and Gynaecology, Department of Anaesthesia, and the nursing staff who extended their support for patient selection and completion of the study.