A randomized, controlled trial of immersive virtual reality analgesia, during physical therapy for pediatric burns

Abstract

This randomized, controlled, within-subjects (crossover design) study examined the effects of immersive virtual reality as an adjunctive analgesic technique for hospitalized pediatric burn inpatients undergoing painful physical therapy. Fifty-four subjects (6–19 years old) performed range-of-motion exercises under a therapist's direction for 1–5 days. During each session, subjects spent equivalent time in both the virtual reality and the control conditions (treatment order randomized and counterbalanced). Graphic rating scale scores assessing the sensory, affective, and cognitive components of pain were obtained for each treatment condition. Secondary outcomes assessed subjects’ perception of the virtual reality experience and maximum range-of-motion. Results showed that on study day one, subjects reported significant decreases (27–44%) in pain ratings during virtual reality. They also reported improved affect (“fun”) during virtual reality. The analgesia and affect improvements were maintained with repeated virtual reality use over multiple therapy sessions. Maximum range-of-motion was not different between treatment conditions, but was significantly greater after the second treatment condition (regardless of treatment order). These results suggest that immersive virtual reality is an effective nonpharmacologic, adjunctive pain reduction technique in the pediatric burn population undergoing painful rehabilitation therapy. The magnitude of the analgesic effect is clinically meaningful and is maintained with repeated use.

Introduction

Physical therapy is a critical, though painful, component of burn rehabilitation therapy. Early and aggressive physical therapy can help counter the decreased range of motion and severe contractures that can develop secondary to burn or associated skin grafting [1], [2]. As a result, burn rehabilitation therapy is often key to improving functional outcome and minimizing long-term disability. Unfortunately, patients may be reluctant to participate fully in physical therapy due to the significant procedural pain that can be triggered by the very activities that are intended to help them heal [3], [4].

Traditionally, pre-procedure systemic opioid administration has been the treatment method of choice for management of rehabilitation-related pain [5]. However, opioid side effects (including nausea, vomiting, pruritis, urinary retention, constipation, respiratory depression, tolerance and risk of addiction are well known), and can limit their clinical use [6], [7], [8]. Despite the liberal use of opioids in the setting of burns, burn pain – particularly procedural pain – continues to remain undertreated [9], [10], [11]. For example, recent studies demonstrate that burn patients report a mean procedural pain score as high as 7 on a scale of 1–10 despite the use of opioids [12], and frequently report severe pain during wound care [11].

Due to inadequate pain control with opioid analgesics alone, nonpharmacologic analgesic techniques have been promoted as clinically useful adjuncts [2], [13]. Such techniques as hypnosis [2], [14], imagery [15], and biofeedback [16] have been shown to significantly reduce pain when used to augment pharmacologic analgesics. More recently, immersive virtual reality has been suggested as an additional choice. This treatment may be particularly effective because it provides an interactive, computer-generated virtual environment that is highly distracting to the user/patient [17]. By drawing heavily upon conscious attention, virtual reality distraction theoretically leaves fewer cognitive resources available to evaluate nociceptive input, resulting in less pain during otherwise painful procedures [18], [19], [20]. Published investigations in settings of burn wound care [17], [21], [22] and post-burn physical therapy [23], [24], [25] suggest that immersive virtual reality may be particularly applicable to this challenging clinical pain population. Furthermore, a previous preliminary study in a small number of patients suggested that the analgesic effect of virtual reality does not appear to extinguish with repeated use [23]. However, previous assessments of virtual reality in the setting of post-burn physical therapy are limited in subject numbers and have not yet focused on children [17], [23], [24].

In the current study we utilized a within-subjects design to compare the effectiveness of adjunctive, immersive virtual reality with that of conventional pharmacologic treatment alone during one or more post-burn physical therapy sessions in the inpatient setting. We hypothesized that the addition of immersive virtual reality to each subject's standard analgesic regimen for active-assisted range-of-motion physical therapy would result in better pain control, as well as increase the maximum range-of-motion that could be achieved by the therapist. We also hypothesized that with repeated use, the amount of pain reduction obtained with adjunctive virtual reality would be maintained.