Individuals With Prior Chronic Pain and Long-Term Opioid Treatment May Experience Persistence of That Pain Even After Subsequent Complete Cervical Spinal Cord Injury: Suggestions From a Prospective Case-Controlled Study

Abstract

Objective: To determine whether chronic pain persists after complete spinal cord injury (SCI).

Design: Prospective observational study regarding the outcome of pre-existent chronic pain of inpatients admitted with new clinically diagnosed complete cervical SCI. For patients who acknowledged chronic pain of ≥3 years duration before the SCI, further questions explored whether they still experienced that pain, whether they were experiencing current posttraumatic pain, and whether they had any past exposure to opioids. The included patients were identified during the initial consultation in the trauma center for treatment of the SCI.

Setting: Level I trauma center.

Participants: From a total of 49 participants with acute cervical SCI with clinically diagnosed complete motor and sensory tetraplegia admitted between 2018 and 2020, 7 were selected on the basis of a history of chronic pain.

Intervention: Collected complete history and performed physical examination with serial follow-ups during the acute hospital stay until death or discharge.

Main outcome measures: The primary outcome was a finding of chronic pain experienced before new clinical diagnosis of complete SCI, compared with whether or not that pain continued after the SCI injury. The secondary outcome was the relation of persistent pain with opioid use; it was formulated after data collection.

Results: Among 49 patients with clinically diagnosed complete cervical SCIs, 7 had experienced prior chronic pain. Four participants experienced a continuation of the prior pain after their complete tetraplegia (4/7), whereas 3 participants did not (3/7). All the participants with continued pain had been previously treated with opioids, whereas those whose pain ceased had not received chronic opioid therapy.

Conclusions: There may be a unique form of chronic pain that is based in the brain, irrespective of peripheral pain or spinal mechanisms. Otherwise healthy people with longstanding antecedent chronic pain whose pain persists after acute clinically complete SCI with tetraplegia may provide a new model for evaluation of brain-based pain. Opioids may be requisite for this type of pain.

Keywords: Analgesics, Opioid; Central pain; Chronic pain; Low back pain; Phantom limb; Rehabilitation; Spinal cord injuries; Tetraplegia.

Graphical abstract

Fig 1

Strengthening the Reporting of Observational Studies in Epidemiology flowchart for prior chronic pain persisting after complete spinal cord injury study. The Strengthening the Reporting of Observational Studies in Epidemiology diagram outlines the process of participant selection. The market/population of the trauma center includes 21 surrounding counties but excludes nearby states. The estimated prevalence of chronic pain in 2020 was 20%, n=180,000; of those, 55% had low back pain or leg pain, n=100,000.