**3. Conclusion**

**2.15. The mechanism and effects of IVLT in chronic pain**

non-specific effects of treatment [292].

84 Pain Relief - From Analgesics to Alternative Therapies

and trust in the healthcare team.

munication, lack of appropriate help).

tributes to decreased pain and improved functioning [309–311].

onward progress of any chronic pain management plan.

The specific effects of IVLT rely on the pharmacological action of lidocaine. However, other elements of care are also critically important especially the psychosocial dynamics of the diagnosis and treatment process. Three mechanisms contribute to improvement in a patient's pain or functioning; the specific or intended effects of treatment, natural history of the disease and

One non-specific treatment effect likely to improve treatment outcomes is high pre-treatment expectations of recovery [293–299]. Factors shown to modulate pre-treatment expectations include dispositional optimism [300–302], sex [297, 303], age [303], education level [297, 303], clinician-patient interactions [304] and degree of psychological distress [297]. Expectations can be enhanced by verbal suggestions, conditioning and imagery [299]. Influences likely to improve treatment outcomes include high expectations, no pre-existing mood disorder, low levels of anxiety, acceptance of the chronic pain diagnosis, a desire to get better, a need to return to a previous level of functioning, motivation and good clinician-to-child relationship

Children and youth with chronic pain will require a lot of effort on the part of the clinicians to establish trust as they have met with many previous different healthcare workers; they may have been given mixed messages regarding the aetiology of pain, and potentially exposed to a negative encounter (not feeling believed that they have pain, lack of empathy, poor com-

To gain a child or youth's trust and that of their parents requires good communication [304–306]. This demands devotion of enough time to listen and extract a precise pain history, use of appropriate language and terminology, developmentally appropriate explanation of concepts [307] as well as understanding family culture, beliefs, hopes and fears. Trust necessitates that; potentially embarrassing questions are asked separately and in confidence and that the healthcare team convey empathy and expertise/credibility in chronic pain management. Introducing appropriate humour into the dialogue also helps to establish good rapport. It is also important to explain to a child/youth with ongoing pain that the healthcare team will attempt to minimise any pain on examination. During the initial assessment good education, establishing an agreed workable goal-directed and achievable management plan positively alters patient outlook as well as responses to treatment [298, 308]. Communicating positive expectations of treatment also con-

Psycho-social effects such as sadness, frustration, anxiety, anger, catastrophization or depression are the detrimental factors that are associated with continuation or worsening of pain. If these psychological factors remain unrecognized and untreated, they become barriers to the

Without the evidence of a randomised double-blind placebo controlled trial, it is not easy to discern the over-riding beneficial therapeutic modality in the chronic pain case series presented. It could be argued that IVLT responsiveness, in tandem with good rapport and trust in the healthcare team, represents a placebo response. Such a response is defined as 'the psychobiological response seen after administration of a non-therapeutic modality'. Placebo Intravenous lidocaine has peripherally and centrally mediated analgesic, anti-inflammatory and anti-hyperalgesic properties [176] with minimal side-effect profile if used at appropriate dosing in properly selected children/youths. It is ideally placed to be a useful adjunct in perioperative pain management to improve comfort, reduce opioid requirements and reduce the attendant opioid side effect profile.

The analgesic properties reflect the variable dose, time dependant, multimodal aspect of its action on voltage-gated Na channels and other receptors that affect nociceptive transmission pathways [23, 24, 45, 117, 146–148, 159, 162]. The anti-inflammatory effects of lidocaine are attributable to attenuation of neurogenic inflammation and subsequent blockade of neural transmission at the site of tissue injury [146, 162, 164, 165, 167].

The anti-hyperalgesic effect of lidocaine, through suppression of peripheral and central sensitization also diminishes the neuro-inflammatory response to pain [25, 168–171, 173, 325]. A basic understanding of pain physiology and pathophysiology is essential to understand how these three beneficial components of IVLT are effecting this response.

Evidence from adult work and clinical experience with paediatric patients indicates that IVLT is a modality, which needs to be considered for major surgical procedures where a regional technique is not indicated. This has promise to improve post-operative pain, reduce opioid requirements and prevent central sensitisation. More work needs to be done to demonstrate effective dose response and plasma levels of lidocaine that are associated with analgesic efficacy for different surgical pain models and whether continuation of the infusion into the postoperative phase will further reduce acute or chronic postsurgical pain.

Chronic pain of childhood is an extremely complex condition that can have devastating effects on physical, psychological and social functioning. The inter-disciplinary team management approach, based on pharmacology, physiotherapy and psychology, is the standard of care for children with severe or ongoing chronic pain. IVLT is a modality that may be considered when the history and examination findings confirm a central, neuropathic or CRPS aspect of the presenting pain. The current lack of evidence-base to support this recommendation does necessitate full disclosure of risks and benefits for informed consent and shared decision making to occur. IVLT must be explained in the right context as a small part of the multi-disciplinary care package, which focuses on de-medicalization and self-management. A singular focus on reducing pain intensity without considering improvement in physical activity, social functioning and overall quality of life is distinctly misguided. Treatment expectations need to be clear that IVLT is used to improve comfort to enable physiotherapy/physical functioning to go ahead and needs to be performed in tandem with all the other multi-disciplinary aspects of care.

Pain clinicians need to engage in large multi-site randomised controlled trials to provide the evidence-base to determine that IVLT is indeed an effective and safe treatment option in acute preventative multimodal analgesia and as an adjunct in the multi-disciplinary care of chronic pain in the paediatric population.
