**6. Conclusion**

*4.2.6. Multimodal analgesia*

46 Pain Management in Special Circumstances

incidence and severity of CPSP.

severity of CPSP [122, 123].

*4.2.8. Glucocorticoids*

outcomes [82].

**5. Future directions**

*4.2.7. Non-steroidal anti-inflammatory drugs (NSAIDs)*

Multimodal analgesia has become the widely accepted modality of treatment for perioperative pain. It is utilising different regimens of different classes of medications according to the type of the surgical procedure and the institute where surgery is performed [115]. The main aim of multimodal analgesia is to target several peripheral and CNS mechanisms to maximise pain reduction, reduce opioids requirements and to decrease opioid-related side effects [103, 107]. A few studies have explored the effects of multimodal analgesia on CPSP prevention. The evidence indicated positive effects at 3 months [116] and at 1 year following surgery [117]. Additional studies are required to study the effects of multimodal analgesia on different types of surgical procedures and to find out whether its preventive effects do indeed reduce the

Prostaglandins are one of the inflammatory mediators activated during surgery which has a possible role in CPSP pathophysiology. NSAIDs are a group of medications which are widely used for their anti-inflammatory properties. They reduce the pain and inflammation through the inhibition of the synthesis of prostaglandins by inhibiting COX-1 and COX-2 receptors. NSAIDs can reduce secondary hyperalgesia and central sensitization [118, 119]. One study showed that Celecoxib (COX-2 inhibitor) had reduced post-operative pain, the need for post-operative opioid analgesia [120] and meanwhile did not inhibit bone healing following arthroplasty surgery [121]. In summary, the available clinical trials are heterogeneous and differ in the following: the type of drug used, follow-up time point and pain outcomes. None of these trials demonstrated a significant impact of NSAIDs on reduction in the incidence or

Glucocorticoids prevent pain by expressing anti-inflammatory properties and by preventing central sensitization [124]. Three trials studied the effects of perioperative corticosteroid on CPSP. The studies used different types of steroids Dexamethasone, Methylprednisolone and Hydrocortisone. A Cochrane review included these clinical trials. The results were inconclusive, and the heterogeneity precluded any possible meta-analysis. The heterogeneity was due to variations in drugs used, follow-up time intervals and the measured pain

CPSP remains as a challenging clinical problem. There are several areas which are promising and can be explored further in the future. Investigators could focus more on the better CPSP is a complex process which is not fully understood. When it occurs, it affects the patients' quality of life. Based on our current understanding of the pathophysiology, nerve injury and inflammation are the two main responsible mechanisms for the development of CPSP. Specific risk factors, which make some individuals at a higher risk than others for CPSP, have been identified. Timely identification of these individuals based on their risk profile allows us to develop appropriate interventions. Several modalities and interventions for CPSP prevention have been investigated. These include pre-emptive and perioperative interventions (**Table 1**). CPSP prevention is an important area for future research in view of the methodological problems with the majority of available studies.

Adapted with permission from reference [125].

**Table 1.** Evidence-based strategies to reduce the risk of chronic post-surgical pain (CPSP).
