Pain, function, and acute neuropathic pain up to one month after surgery: a registry-based analysis

Introduction: Knowledge of how patients experience pain and patterns of resolution beyond the first days after surgery is limited. Acute neuropathic pain (ANeuP) following surgery is rarely assessed. Objectives: We aimed to characterize pain intensity, pain-related functional impairment, ANeuP, and to describe patterns of resolution in a large cohort undergoing diverse surgical procedures up to 1 month postoperatively, the subacute period. Methods: This was an observational, multicentre study. Outcomes were assessed on postoperative days (PODs) 1/7/30 using the PAIN OUT registry methodology. The primary endpoint was the change in pain-related interference between POD7 and POD30. Patient subgroups were identified using cluster analysis. Results: A cohort of 1,153 patients (median age 49; 67% female) was enrolled. By POD30, pain-related functional interference decreased ( P < 0.001, moderate-to-large effect). The cluster analysis identified 3 subgroups: Minimal-pain resolution (16% of the cohort), Slow-pain resolution (30.5%), and Fast-pain resolution (53.5%). By POD30, patients in the Slow- and Fast-pain resolution clusters had largely recovered, differing in recovery rate. Those in the Minimal-pain resolution cluster showed limited improvement from POD1. By POD30, these patients still experienced mild–moderate pain and interference, with 40% screening positive for ANeuP and 24% taking opioids. Risk factors included chronic preexisting pain and thoracic or orthopaedic surgery. Conclusion: Although the majority of patients in the cohort largely recovered in terms of pain and interference by POD30, 16% belonged to the Minimal-pain resolution cluster. These patients may benefit from proactive identification and management by anaesthetists, surgeons, and practitioners in the community before surgery or in the early weeks after surgery.