AA

Classification of Pain

You tell Mr. A.H. that pain is common after spinal cord injury and important to get under control early to minimize any negative effect it might have on his rehabilitation. As mentioned earlier, as a result of the increased activity of being in rehabilitation, he has started to complain of pain in his neck and shoulders, and daily headaches. Mr. A.H. also reports burning/”pins and needles” pain in his legs in addition to the pain in his neck and shoulders.. The team wonders how to describe Mr. A.H.’s pain in discussion.
Q6. Describe a classification system for pain related to SCI?
1. Post-SCI pain can most commonly be divided into neuropathic or musculoskeletal pain.
2. The IASP (International Association for the Study of Pain) Classification of Post-SCI Pain is shown below.

A Task Force on Pain Following Spinal Cord Injury of the International Association for the Study of Pain has introduced a taxonomy (Table 1), which classified SCI pain based on presumed etiology.

Table 1. Proposed IASP Classification of Pain Related to SCI

Broad Type
(Tier 1)

Broad System
(Tier 2)

Specific Structure/Pathology
(Tier 3)
Nociceptive Musculoskeletal -Bone, joint, muscle trauma, or inflammation
-Mechanical instability
-Muscle spasm
-Secondary overuse syndromes
Visceral -Renal calculus,bowel, sphincterdysfunction, etc.
-Dysreflexic headache
Neuropathic Above Level -Compressive mononeuropathies
-Complexregional pain syndromes
At Level -Nerve root compression (including cauda equine)
-Syringomyelia
-Spinal cord trauma/ischemia (transitional zone, etc.)
-Dual-level cord and root trauma (double lesion syndrome)
Below Level -Spinal cord trauma/ischemia (central dysesthesia syndrome, etc.)

Tools such as the Leeds assessment of neuropathic symptoms and signs (LANSS) Pain Scale and the DN4 can be helpful in deciding if there is a component of neuropathic pain.

To view the LANSS Pain Scale and DN4 questionnaire please see: LANSS and DN4

For more information please see: Classification of SCI Pain

 

The clinical team also discusses the merits of the Classification System for Chronic Pain in SCI test for patient assessment.
Q7. Describe the Classification System for Chronic Pain in SCI.
1. Neuropathic pain is divided into 4 subcategories: SCI pain, transition zone pain, radicular pain and visceral pain (see Table 2).
2. Musculoskeletal pain is divided into mechanical spine pain and over use pain.
3. This scheme is design to help with the standardization of pain terminology used in the SCI population. Pain is ca tegorized by pain location and distribution, as related to level of spinal injury (e.g. above level, at level or below level). This information is combined with a classification of the subject’s SCI pain.
Q8. Describe how the Classification System for Chronic Pain in SCI is determined.
1. Typically, a questionnaire is administered by a clinician; it could also be completed by the patient.
2. The person identifies the worst pain problem on a body diagram and indicates whether pain worsens with activity, position or change of position or light touch.
3. This procedure is repeated for second worse pain etc. (see Table 2 for categorization).

Table 2. Classification System for Chronic Pain in SCI

Pain Category
(major)

Pain Category
(Specific)

Location Related to activity Affected by position Worse with light touch
Neurologic SCI pain Below injury in area without normal sensation + / – + / –
Transition zone pain At level of injury, bilateral +
Radicular pain At any dermatome level, usually unilateral, usually radiates + +
Visceral In abdomen
Musculoskeletal Mechanical spine pain In back or neck, often bilateral + +
Overuse pain Often above injury in areas of normal sensation in an incomplete, can be below + + / –

 

Note: + yes, – no, + maybe
Q9. What are the Advantages of the Classification System for Chronic Pain in SCI?
1. This tool has the best reliability (within (κ=0.68) and between (κ=0.66) raters), and standardized system for classifying pain in people with SCI using well defined terminology (See Table 3).
Q10. What are the disadvantages of the Classification System for Chronic Pain in SCI?
1. There is no information about validity or responsiveness and reliability results are based on a single study. Time taken to complete is considerable.

Summary – Classification System for Chronic Pain in SCI

Interpretability – This pain classification provides a nice summary table that makes it easy for clinicians to identify key problem areas that the patient has expressed.

Acceptability – The initial patient burden is high however follow up session will require less time. Interview format improves utility for those with limited hand function.

Feasibility – No special equipment or training is necessary however expertise understanding pain would be an asset. See article for a copy of the tool.

Table 3. Classification System for Chronic Pain in SCI

Reliability Validity Responsiveness
Rigor Results Rigor Results Rigor Results Floor/Ceiling
++ Inter O ++
Intra O ++
N/A N/A N/A N/A N/A

Note: +++ = Excellent; ++ = Adequate; + = Poor; N/A=Insufficient information; Inter O=Interobserver; Intra O=intraobserver

For more information please see: Classification System for Chronic Pain in SCI