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

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.

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.

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.

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.

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.