Predicting the Risk for Central Pain Using the Sensory Components of the International Standards for Neurological Classification of Spinal Cord Injury

Abstract

Central neuropathic pain (CP) after spinal cord injury (SCI) is excruciating and difficult to manage. Pre-emptive treatment could be initiated in patients at risk for CP providing that it can be predicted. A combination of psychophysical tests could predict CP, but the process necessitates sophisticated equipment and constant monitoring. A simple predictive tool for CP is required. The aim of this study was to test the predictability for CP of the sensory component of the International Standards for Neurological Classification of Spinal Cord Injury (SC-ISNCSCI), routinely performed on all SCI patients. In an historical-prospective study, the SC-ISNCSCI and background variables were extracted from medical records of 115 SCI patients. In a prospective study, 20 SCI patients underwent the SC-ISNCSCI at admission and were followed-up for 12 months. In both studies, pinprick (PP) and light touch (LT) scores from the SC-ISNCSCI and the difference between them (LT-PP) were compared between those who eventually developed CP and those who did not. Heat-pain and touch thresholds were measured and correlated with the SC-ISNCSCI to test its validity. In both studies, patients who developed CP had, prior to CP, lower PP than LT scores, and lower PP scores than those who did not develop CP. At-level delta LT-PP score>1 best predicted CP; the odds of developing CP with LT-PP>1 was 24.4 times that of the reverse category (LT-PP<1). Heat-pain and touch thresholds significantly correlated with PP and LT. We conclude that the SC-ISNCSCI can be used as a clinical biomarker of CP with high probability.

Increased psychological distress among individuals with spinal cord injury is associated with central neuropathic pain rather than the injury characteristics

“…Interestingly, the CNP characteristics did not correlate with SCI characteristics including level of injury, AIS score and cause of injury. This finding is in agreement with previous studies [27,55,56]. The finding further support the role of the psychological sequel of SCI, or alternatively the psychological predisposition, in the emergence and perhaps in the chronification of CNP.…”

Neuropathic pain and spasticity: intricate consequences of spinal cord injury

“…This theory is supported by studies finding a correlation between evoked at-level pain and ongoing below-level pain. [70][71][72] Further studies that carefully assess various symptoms of SCI and their changes over time and a better understanding of the translation of behavioral correlates of pain and spasticity from animals to humans and back are needed in order to further understand how various changes in interdependent neuronal networks can result in different symptoms and signs.…”

Assessments of sensory plasticity after spinal cord injury across species

“…One limitation of this assessment is that dermatomes that have either decreased sensation or are hypersensitive fall into to the same category of impaired sensation. Only a few studies looked at the relation between the ISNCSCI sensory measures and the development of NP [42,43]. Hari et al found that patients that suffer from NP have enhanced sensory recovery measured by pinprick sensation in comparison to SCI patients that do not develop NP [42].…”

“…Hari et al found that patients that suffer from NP have enhanced sensory recovery measured by pinprick sensation in comparison to SCI patients that do not develop NP [42]. Another study found that lower at-level pinprick scores were more predictive than light touch scores for NP development [43]. …”