Altered Sensory Insular Connectivity in Chronic Postsurgical Pain Patients

Abstract

Chronic postsurgical pain (CPSP) occurs in up to 50% of individuals after surgeries and 32% after hysterectomy, leading to major adverse effects on quality of life and socioeconomic burden. Little is known about whether and how large-scale neural networks being affected in CPSP, particularly with regard to the functional connectivity (FC) of insula which is known to be the hub of the intrinsic neural network playing a critical role in pain processing. Here, we sought to examine the dynamics of insular FC in the context of noxious stimuli in CPSP patients. To this aim, resting state fMRI data were acquired, before and after acute heat pain stimulation, from 11 individuals with chronic post-hysterectomy pain (CPHP) and 22 age-matched healthy controls (HCs) who had a hysterectomy but without chronic post-surgical pain. We examined whole-brain FC were mapped by seeding at the sensorimotor and chemosensory subfields of the insula and found significant group × stimulation interaction effects. Specifically, the HC group had increased FC between the left sensorimotor insula and right angular and middle occipital gyrus (MOG) and increased FC between the left chemosensory insula and bilateral angular and MOG following pain stimulation. In contrast, such pain stimulation related FC changes were absent in the CPHP group. Furthermore, higher insular FC at baseline and smaller increased insular FC after pain stimulation correlated with clinical pain scores in CPHP patients. Our findings suggest that CPSP is associated with altered dynamics of large-scale functional networks anchored in the insula.

Reduced excitatory neurotransmitter levels in anterior insulae are associated with abdominal pain in irritable bowel syndrome

“…Our study examined aINS neurotransmitter levels in women with IBS, a mechanism that might contribute to aberrant insular function consistently observed in chronic visceral pain disorders. 3,7,9,19,32,38,50 We observed decreased concentrations of the excitatory neurotransmitter Glx in bilateral aINS in women with IBS compared with healthy women, whereas no significant group differences were found in aINS GABA+ concentrations. Furthermore, we demonstrated that longer duration of pain predicted lower Glx concentrations in the right aINS while lower Glx concentrations in the left aINS were predicted by less use of adaptive pain-coping strategies.…”

Altered thalamic neurotransmitters metabolism and functional connectivity during the development of chronic constriction injury induced neuropathic pain

“…It has been confirmed that the insula is the nerve network hub of pain signal transmission. A clinical study has also suggested that chronic neuralgia is associated with fluctuations in the functional network and the activation of excitatory neurons in the insula [49,50]. As we knew, the dorsal posterior insula is one region that is consistently active at a high level during pain, as seen during functional brain imaging.…”

Increased thalamo‑cortical functional connectivity in patients with diabetic painful neuropathy: A resting‑state functional MRI study

“…Patients with classical trigeminal neuralgia (CTN) had symptoms characterized by orbital pain, decreased corneal reflex and decreased vision ( 34 ). Individuals with chronic post-hysterectomy pain had decreased FC between the left sensorimotor insula and the right angular and middle occipital gyri (MOG), as well as between the left chemosensory insula, the bilateral angular gyri and the MOG following pain stimulation ( 37 ).…”