On the Relationship Between White Matter Structure and Subjective Pain. Lessons From an Acute Surgical Pain Model

Abstract

Background: Pain has been associated with structural changes of the brain. However, evidence regarding white matter changes in response to acute pain protocols is still scarce. In the present study, we assess the existence of differences in brain white matter related to pain intensity reported by patients undergoing surgical removal of a mandibular impacted third molar using diffusion tensor imaging (DTI) analysis.Methods: 30 participants reported their subjective pain using a visual analog scale at three postsurgical stages: under anesthesia, in pain, and after the administration of an analgesic. The diffusion data were acquired prior to surgery.Results: DTI analysis yielded significant positive associations of fractional anisotropy in white matter areas related to pain processing (corticospinal tract, corona radiata, corpus callosum) with the differences in pain between the three postsurgery stages. Extent and location of these associations depended on the magnitude of the subjective pain differences. Tractography analysis indicated that some pain–tract associations are significant only when pain stage is involved in the contrast (posterior corona radiata), while others (middle cerebellar peduncle, pontine crossing) are only when anesthesia is involved in the contrast.Conclusions: The association of white matter fractional anisotropy and connectivity, measured before the pain stages, with subjective pain depends on the magnitude of the differences in pain scores.

Structural brain connectivity predicts early acute pain after mild traumatic brain injury

“…Other studies show associations between white mater integrity and pain, 20,21,37,39 and more to the point, it has been previously shown that white matter properties collected before the surgery may predetermine acute postsurgical pain. 61 Here, we further provide support to this idea by showing that postinjury acute pain can also be predicted from the structural connectome quite early after injury. The novelty of the evidence here lies in the clinical sample studied: our participants did not have any pain before injury and were scanned within hours of the accident, making them an ideal group to study injuryrelated, early acute pain in an ecological manner.…”

“…In conclusion, our data instead favor the idea that observed WM properties reflect an a priori brain predisposition for pain sensitivity, also in line with previous research showing that white matter properties before surgery predetermine postsurgical pain. 61 Although reasonable, this justification requires demonstration from further studies where patients can be scanned before the onset of pain (eg, before surgery).…”

White matter microstructural alterations in patients with neuropathic pain after spinal cord injury: a diffusion tensor imaging study

“…Additionally, the posterior cingulate cortices of both sides are connected structurally and functionally by the posterior segment of the corpus callosum, which is a key functional hub of the default mode network ( 22 , 40 , 42 , 45–47 ). Torrecillas-Martínez et al ( 20 ) used DTI to assess brain WM changes related to subjective pain perception in an acute surgical pain model. They compared three postsurgical pain stages and showed significant positive associations between FA in the posterior parts of the corpus callosum, corticospinal tract, and corona radiata and pain processing ( 20 ).…”

“…Torrecillas-Martínez et al ( 20 ) used DTI to assess brain WM changes related to subjective pain perception in an acute surgical pain model. They compared three postsurgical pain stages and showed significant positive associations between FA in the posterior parts of the corpus callosum, corticospinal tract, and corona radiata and pain processing ( 20 ). NP usually arises from central sensitization and nociceptive system hyperexcitability ( 11 , 48 ).…”

Clinical vitamin D levels are associated with insular volume and inferior temporal gyrus white matter surface area in community-dwelling individuals with knee pain

“…We have previously shown marked decreases in white matter integrity in older adults with musculoskeletal pain, and that these decreases mediated the pain-gait relationship ( Cruz-Almeida et al, 2017 ). White matter abnormalities have also been implicated in other pain disorders such as orofacial pain disorders ( Moayedi and Hodaie, 2019 ) and also severity of surgical pain ( Torrecillas-Martínez et al, 2020 ). In our study, we noted decreased surface area of white matter in the ITG in individuals with insufficient Vitamin D levels compared to those with optimal vitamin D levels.…”