BACKGROUNDPerioperative regional anaesthesia may protect from persistent postsurgical pain (PPSP) and improve outcome after total knee arthroplasty (TKA).OBJECTIVESAim of this study was to evaluate the impact of regional anaesthesia on PPSP and long-term functional outcome after TKA.DESIGNA web-based prospective observational registry.SETTINGFive Italian Private and University Hospitals from 2012 to 2015.PATIENTSUndergoing primary unilateral TKA, aged more than 18 years, informed consent, American Society of Anesthesiologists (ASA) physical status classes 1 to 3, no previous knee surgery.INTERVENTION(S)Personal data (age, sex, BMI and ASA class), preoperative pain assessed by numerical rating scale (NRS) score, and risk factors for PPSP were registered preoperatively. Data on anaesthetic and analgesic techniques were collected. Postoperative pain (NRS), analgesic consumption, major complications and patient satisfaction were registered up to the time of discharge. PPSP was assessed by a blinded investigator during a phone call after 1, 3 and 6 months, together with patient satisfaction, quality of life (QOL) and walking ability.MAIN OUTCOME MEASURESExperience of PPSP according to the type of peri-operative analgesia.RESULTSFive hundred sixty-three patients completed the follow-up. At 6 months, 21.6% of patients experienced PPSP, whereas autonomy was improved only in 56.3%; QOL was worsened or unchanged in 30.7% of patients and improved in 69.3%. Patients receiving continuous regional anaesthesia (epidural or peripheral nerve block) showed a lower NRS through the whole peri-operative period up to 1 month compared with both single shot peripheral nerve block and those who did not receive any type of regional anaesthesia. No difference was found between these latter two groups. Differences in PPSP at 3 or 6 months were not significantly affected by the type of anaesthesia or postoperative analgesia. A higher NRS score at 1 month, younger age, history of anxiety or depression, pro-inflammatory status, higher BMI and a lower ASA physical status were associated with a higher incidence of PPSP and worsened QOL at 6 months.CONCLUSIONContinuous regional anaesthesia provides analgesic benefit for up to 1 month after surgery, but did not influence PPSP at 6 months. Better pain control at 1 month was associated with reduced PPSP. Patients with higher expectations from surgery, enhanced basal inflammation and a pessimistic outlook are more prone to develop PPSP.TRIAL REGISTRATIONClinicaltrials.gov identifier: NCT02147730

Poor acute pain control and inflammation are important risk factors for Persistent Postsurgical Pain (PPSP). The aim of the study is to investigate, in the context of a prospective cohort of patients undergoing hernia repair, potential risk factors for PPSP. Data about BMI, anxious-depressive disorders, neutrophil-tolymphocyte ratio (NLR), proinflammatory medical comorbidities were collected. An analysis for correlation between comorbidities and PPSP was performed in those patients experiencing chronic pain at 3 months after surgery. Tramadol resulted less effective in pain at movement in patients with a proinflammatory status. Preoperative hypertension and NLR > 4 were correlated with PPSP intensity. Regional anesthesia was significantly protective on PPSP when associated with ketorolac. Patients with pain at 1 month were significantly more prone to develop PPSP at 3 months. NSAIDs or weak opioids are equally effective on acute pain and on PPSP development after IHR, but Ketorolac has better profile in patients with inflammatory background or undergoing regional anesthesia. Drug choice should be based on their potential side effects, patient's profile (comorbidities, preoperative inflammation, and hypertension), and type of anesthesia. Close monitoring is necessary to early detect pain conditions more prone to progress to a chronic syndrome.

Local infiltration and continuous infusion of surgical wound with anesthetics are parts of multimodal analgesia for postoperative pain control. The techniques, given the simplicity of execution that does not increase the timing of the intervention and does not require additional technical skills, are applied in several kinds of surgeries. The continuous wound infiltration can be used for days and a variety of continuous delivery methods can be chosen, including patientcontrolled analgesia, continuous infusion or intermittent bolus. The purpose of this narrative review is to analyze the literature, in particular by researching the safety, efficacy and current perspectives of continuous wound infiltration for postoperative pain management in different surgical settings. We have identified 203 articles and 95 of these have been taken into consideration: 17 for the lower limb surgery; 7 for the upper limb surgery, 51 for the laparotomy/ laparoscopic surgery of the abdominopelvic area, 13 studies regarding breast surgery and 7 for cardiothoracic surgery. The analysis of these studies reveals that the technique has a variable effectiveness based on the type of structure involved: it is better in structures rich in subcutaneous and connective tissue, while the effectiveness is limited in anatomic districts with a greater variability of innervation. However, regardless the heterogeneity of results, a general reduction in pain intensity and in opioid consumption has been observed with continuous wound infiltration: it is an excellent analgesic technique that can be included in the multimodal treatment of postoperative pain or represents a valid alternative when other options are contraindicated.