Chronic Pain Following Fracture-Related Surgery: Posttraumatic Rather Than Postsurgical Origin Promotes Chronification—A Prospective Observational Study With 1-Year Follow-up

Abstract

BACKGROUND: Chronic posttraumatic/postsurgical pain (CPSP) is common after traumatic or surgical damage. Exposure to both trauma and surgery, with the potential for repeated bone and nerve damage, may increase the risk of CPSP after fracture-related surgery. But the (long-term) incidences of CPSP and neuropathic CPSP and the ensuing burdens are unknown. Therefore, the patients were prospectively assessed within 1 year, and the patient-specific characteristics were explored. METHODS: Between 2017 and 2018, 127 patients (age: 52.9 ± 17.1 years, male: 55.1%) with traumatic fractures needing osteosynthesis (extremities: 91.3%) were assessed posttrauma (before surgery), postsurgery at days 1 to 5, 6 weeks, 3 and 12 months. The primary outcomes are as follows: incidence at 3 and 12 months of CPSP (defined as pain intensity on a numerical rating scale [NRS: 0–10] ≥3), secondary exploration: neuropathic CPSP (NRS ≥3 and Douleur Neuropathique 4 interview [DN4i] score ≥3 [Douleur Neuropathique interview: 0–7]); burden: quality of life (QoL, the EuroQOL five dimensions questionnaire [EQ-5D-3L] descriptive system); and inter alia, the number of analgesics (trial registration: DRKS00011601). RESULTS: The incidence of CPSP was 57.1% (52/91, n/N) at 3 and 42.7% (35/82) at 12 months postsurgery, including neuropathic CPSP 7.7% (4/52) and 17.1% (6/35), respectively. Descriptively, posttraumatic higher pain intensity at rest (difference of 0.9 ± 1.8 NRS) and the need for more frequent analgesics (by 34.3%) were associated with CPSP a year after surgery compared to those without. As soon as week 6, these patients had developed descriptively a 15% more impaired QoL, with 25% more impairment after 1 year. The patients with CPSP presented with at least 1 neuropathic symptom 12 months later in 68.6% (24/35) of cases, mainly with an early posttraumatic occurrence (without fulfilling the definition of neuropathic CPSP). CONCLUSIONS: After early fracture-related surgery, high incidences of CPSP (43%) were prospectively observed 1 year postsurgery, up to approximately 1 in 5 patients who had neuropathic CPSP. At the same time, CPSP was accompanied with an impacted QoL and analgesic dependence, both indicating clinical relevance. Moreover, the high incidence and the early posttraumatic occurrence of more intense pain suggest that the initial fracture-related trauma, rather than the surgical trauma, may predominantly trigger CPSP at Y1 (1 year). Therefore, these exploratory results set the direction of required future research. A future clinical hypothesis might be: treat first what hurts first.

Use of regional analgesia to prevent the conversion from acute to chronic pain

“…A prospective observational study ( N = 127) reported a 57% CPSP incidence at 3 months and 43% (with 17% neuropathic pain) at 12 months, which is higher than the CPSP incidence observed after elective limb orthopaedic surgery [37 ▪▪ ]. CPSP risks factors in trauma patients mostly involve posttraumatic high pain intensity and posttraumatic rather than postsurgical origin might promote CPSP development [37 ▪▪ ]. Accordingly, preoperative pain was associated with CPSP at 3 months (incidence 65%) in orthopaedic trauma patients ( N = 303) [38].…”

“…Bone fracture induces sharp nociceptive pain sometimes associated with neuropathic symptoms. A prospective observational study ( N = 127) reported a 57% CPSP incidence at 3 months and 43% (with 17% neuropathic pain) at 12 months, which is higher than the CPSP incidence observed after elective limb orthopaedic surgery [37 ▪▪ ]. CPSP risks factors in trauma patients mostly involve posttraumatic high pain intensity and posttraumatic rather than postsurgical origin might promote CPSP development [37 ▪▪ ].…”

“…Trauma often causes persistent pain, but CPSP incidence and risk factors after fracture fixation remain understudied [37 ▪▪ ]. Bone fracture induces sharp nociceptive pain sometimes associated with neuropathic symptoms.…”

Chronic pain after surgery and trauma: current situation and future directions

“…cut off used for pain intensity and duration), CPSP incidence may widely differ (range from 5% to 85%) 2 . The prospective and retrospective observational cohort studies published in the last decade, including common procedures, both in-and out-patients surgeries 4 , report similar incidences (see Table I) [5][6][7][8][9][10][11][12][13][14][15] . It is worth noting that the presence of a neuropathic component is often mentioned in CPSP and always associated to higher pain severity, more disability and poorer quality of life 16 .…”

Acute pain management and long term outcomes

“…Regional analgesia may help to prevent the manifestations of these mechanisms, particularly the preactivation (priming) of pain-related area into the brain [35]. Trauma often causes intense AP and high stress state which may induce persistent pain [36] and posttraumatic stress disorders (PTSD) [37]. The benefits of early pain management have been highlighted in military personnel who suffered combat-related injury.…”