Dissociation of Spinothalamic Modalities Following Anterolateral Cordotomy

Sharma, Manohar; Marley, Kate; McGlone, Francis; Gupta, Manish

doi:10.1017/cjn.2017.290

Cited by 2 publications

(1 citation statement)

References 7 publications

(17 reference statements)

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“…39 Interestingly, human lesion studies have shown that anterolateral cordotomies of the STT, used for intractable cancer-related pain relief, can lead to dissociated sensory loss. 40-42 In these studies, thermal sensation was not affected by the cordotomy, whereas pinprick pain was lost, suggesting a segregation of thermal and mechano-nociceptive STT fibers. Such dissociated sensory loss has been related to altered spinothalamic conduction in few patient cases with spinal cord lesions, 27 suggesting a somatotopic distribution of fibers within the STT.…”

Section: Discussionmentioning

confidence: 69%

Combined Neurophysiologic and Neuroimaging Approach to Reveal the Structure-Function Paradox in Cervical Myelopathy

et al. 2021

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Objective:To explore the so-called “structure-function paradox” in individuals with focal spinal lesions by means of tract-specific MRI coupled with multi-modal evoked potentials and quantitative sensory testing.Methods:Individuals with signs and symptoms attributable to cervical myelopathy (i.e., no evidence of competing neurological diagnosis) were recruited in the Balgrist University Hospital, Zurich, Switzerland between February 2018 and March 2019. We evaluated the relationship between the extent of structural damage within spinal nociceptive pathways (i.e., dorsal horn, spinothalamic tract, anterior commissure) assessed with atlas-based MRI , and 1) the functional integrity of spinal nociceptive pathways measured with contact heat-, cold-, and pinprick- evoked potentials and 2) clinical somatosensory phenotypes assessed with quantitative sensory testing.Results:Sixteen individuals (mean age 61 years) with either degenerative (N=13) or post-traumatic (N=3) cervical myelopathy participated in the study. Most individuals presented with mild myelopathy (modified Japanese Orthopaedic Association score (mJOA)>15; N=13). 71% of individuals presented with structural damage within spinal nociceptive pathways on MRI. Yet, 50% of these individuals presented with complete functional sparing (i.e., normal contact heat-, cold-, and pinprick- evoked potentials). The extent of structural damage within spinal nociceptive pathways was neither associated with functional integrity of thermal (heat: p=0.57; cold: p=0.49) and mechano-nociceptive pathways (p=0.83) nor with the clinical somatosensory phenotype (heat: p=0.16; cold: p=0.37; mechanical: p=0.73). The amount of structural damage to the spinothalamic tract did not correlate with spinothalamic conduction velocity (p>0.05; rho=-0.11).Conclusions:Our findings provide neurophysiological evidence to substantiate that structural damage in the spinal cord does not equate to functional somatosensory deficits. This study recognizes the pronounced structure-function paradox in cervical myelopathies and underlines the inevitable need for a multi-modal phenotyping approach to reveal the eloquence of lesions within somatosensory pathways.

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