Long-term effects on functional brain networks in adolescents treated for lumbar disc herniation

Background & Aims

Long-term pain is associated with changes in brain function [1], and plasticity in the central nervous system has recently been pointed out as a pain-promoting mechanism in several long-term pain conditions. Long-term low back pain is the leading cause of years lived with a disability [2], for example due to lumbar disc herniation. Lumbar disc herniation is common in adulthood but rare in adolescence [3]. Treatment options include surgery and non-operative methods. Both options are similar in clinical efficacy [4], but the long-term effects on functional brain networks are unknown. The overall aim of the present study was to determine potential long-term effects on pain-related brain networks among individuals who received either surgical or non-operative treatment for lumbar disc herniation in adolescence.

Methods

Functional magnetic resonance imaging (fMRI) was used to assess resting-state brain network connectivity on average 12 years after treatment for individuals who received surgical treatment (n=23) or non-operative treatment (n=12). A group of healthy controls with no history of lumbar disc herniation (n=23) underwent the same exams.

Results

Individuals who received surgical treatment in adolescence exhibited a distinctly different pattern of brain connectivity compared to both the non-operative group and healthy controls. In particular, the connectivity between the somatomotor network and the default mode network was stronger in the surgical treatment group than in the non-operative group. This finding was neither associated with self-reported pain nor lumbar morphology.

Conclusions

Over a decade after treatment, surgical treatment for LDH is associated with differential brain network connectivity compared to non-operative treatment and healthy controls. This is particularly pronounced in the somatosensory-default mode connectivity, which appear to be unrelated to the morphology of the spine and self-reported back pain. Our data thus indicate that the treatment choice for LDH in adolescence could be associated with a long-term imprint on the functional brain connectome.

References

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[2] Collaborators GBDLBP. Global, regional, and national burden of low back pain, 1990-2020, its attributable risk factors, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021. Lancet Rheumatol. Jun 2023;5(6):e316-e329. doi:10.1016/S2665-9913(23)00098-X
[3] Weber H. The natural history of disc herniation and the influence of intervention. Spine (Phila Pa 1976). Oct 1 1994;19(19):2234-8; discussion 2233. doi:10.1097/00007632-199410000-00022
[4] Peul WC, van Houwelingen HC, van den Hout WB, et al. Surgery versus prolonged conservative treatment for sciatica. N Engl J Med. May 31 2007;356(22):2245-56. doi:10.1056/NEJMoa064039