Pain Syndromes After Spinal Cord Injury
SCI · EP 11 · PAIN
Before You Listen
This episode covers the International Spinal Cord Injury Pain (ISCIP) classification, the three-tier framework that separates nociceptive musculoskeletal and visceral pain from at-level and below-level neuropathic pain, the wheelchair-driven shoulder pathology that affects up to 72% of long-duration manual users, the diagnostic trap where autonomic dysreflexia is the only herald of an acute abdomen, the central paradox of burning pain in anesthetic regions, and the pharmacologic algorithm with pregabalin as the only FDA-approved agent for SCI-related neuropathic pain. You will leave knowing every classification tier cold, the Consortium for Spinal Cord Medicine wheelchair fitting numbers, the gabapentinoid-then-tricyclic ladder, why chronic opioids are avoided, and the role of emerging therapies including tDCS, rTMS, and DREZ lesioning.
What you should already know coming in:
- The Modified Ashworth Scale (MAS) and the spasticity ladder from Episode 10 (baclofen, tizanidine, dantrolene, BoNT, intrathecal baclofen).
- The autonomic dysreflexia (AD) trigger sequence from Episode 9 (bladder first, bowel second, then deeper) and the T6 threshold.
- ASIA Impairment Scale (AIS) grades A through E and the concept of complete versus incomplete injury from Episode 3.
Runtime: approximately 50 minutes 32 seconds.
Vignette. A 34-year-old man with a 6-year-old C6 American Spinal Injury Association (ASIA) Impairment Scale (AIS) A complete tetraplegia presents to your physiatry clinic with two distinct pain complaints. First, he reports a 4-month history of constant, burning, electric pain in both legs and feet that he rates 8 out of 10, worse at night, with no clear positional trigger; he has absent sensation to pinprick below T2 on examination. Second, he reports new right shoulder pain over the past 8 weeks, sharp with overhead reach and during transfers, that limits him to 90 degrees of active flexion. He uses a manual wheelchair full-time. He is on no neuropathic pain medication. Vital signs and recent labs are unremarkable.
Classify each pain syndrome under the ISCIP system, name the most likely shoulder diagnosis given his wheelchair history, write a first-line and a second-line pharmacologic regimen for the leg pain naming the only FDA-approved agent for this indication, and explain why you would not start him on a chronic opioid.
(Answer at the end of this chapter)
Section 1: The Burden of Pain and the ISCIP Three-Tier Classification
Bottom line: 65–80% of SCI patients develop chronic pain that does not spontaneously resolve, and the ISCIP taxonomy forces a component-by-component diagnosis (nociceptive vs neuropathic, then subtype, then anatomic source) before a single prescription is written.
Pain after spinal cord injury (SCI) is the most prevalent, persistent, and functionally limiting secondary complication in this population, and its scale and chronicity are tested directly. Epidemiologic studies converge on a chronic pain prevalence of 65–80% when chronic is defined as pain persisting beyond 3 months from injury. Within that majority, 30–40% rate their pain as severe, scoring 7 or higher out of 10 on a numerical rating scale. Pain intensity does not reliably correlate with injury level, completeness, sex, or paraplegia versus tetraplegia. Longitudinal data confirm that SCI-related pain tends to persist or worsen over time rather than burn itself out, and a majority of patients still report significant pain 5 or more years after injury.
Distinguishing pain intensity from pain interference is essential. Intensity is the loudness of the alarm; interference is the downstream destruction it causes: disrupted sleep, blocked rehabilitation participation, eroded employment, and social withdrawal. Chronic pain after SCI is independently associated with depression, anxiety, sleep disturbance, fatigue, and reduced participation in rehabilitation. In community-reintegration surveys, pain is consistently cited alongside or even above loss of motor function as the primary barrier to returning to work. This is the framing that motivates the pharmacologic and non-pharmacologic algorithms downstream.
The International Spinal Cord Injury Pain (ISCIP) classification was published in 2012 by an international consensus involving the International Association for the Study of Pain (IASP), the International Spinal Cord Society (ISCoS), and the American Spinal Injury Association (ASIA). It is a three-tier hierarchical taxonomy designed to force the clinician to isolate the exact etiology before writing a prescription. Tier 1 divides all pain into three mutually exclusive buckets: nociceptive (intact somatosensory hardware faithfully signaling tissue damage), neuropathic (the somatosensory nervous system itself is the lesioned generator), and other (pain that fits neither, such as fibromyalgia, complex regional pain syndrome, or unknown etiology). Tier 2 subdivides nociceptive pain into musculoskeletal, visceral, and other nociceptive, and subdivides neuropathic into at-level SCI pain, below-level SCI pain, and other neuropathic (such as carpal tunnel syndrome or diabetic peripheral neuropathy not caused by the cord injury itself). Tier 3 specifies the anatomic source (rotator cuff tear, fecal impaction, syringomyelia) and is where the imaging, electrodiagnostic, and physical-exam work lives.
Validation studies show ~79% accuracy for identifying nociceptive pain and ~77% accuracy for neuropathic pain at Tier 1; musculoskeletal pain is the most reliably classified Tier 2 subtype at ~84% accuracy. The single most clinically important property of the framework is that most patients have multiple simultaneous pain types, and each must be classified and targeted separately. A T6 paraplegic may carry rotator cuff impingement (nociceptive musculoskeletal), constipation (nociceptive visceral), an at-level burning band, and diffuse below-level burning. Four problems require four treatment plans. Lumping them as “chronic pain” guarantees inadequate management.
High Yield — ISCIP at-a-glance
- Prevalence: 65–80% chronic pain after SCI; 30–40% rate severe (≥7/10).
- No reliable correlation between pain and level, completeness, sex, or paraplegia versus tetraplegia.
- Tier 1: Nociceptive | Neuropathic | Other (mutually exclusive).
- Tier 2 neuropathic split: at-level (within ±3 dermatomes of NLI) versus below-level (>3 dermatomes below NLI).
- Multiple concurrent pain types are the norm; classify and treat each separately.
- IASP + ISCoS + ASIA authored the 2012 consensus.