Experts agree on framework for phenotyping low back pain


By Selina Wellbelove

12 Feb 2024

Consensus recommendations have beeb developed to guide clinicians in identifying a dominant pain phenotype in patients with low back pain.

The new recommendations “will add to the existing literature as a necessary early step in the process to determine if personalised pain medicine based on pain phenotypes is feasible for low back pain management,” the international group of authors said in a paper published in The Lancet Rheumatology (link here).

The group, comprised of experts from 13 countries, including Australia, has developed a seven-step “decision-making tree” to help identify the predominant pain mechanism – nociceptive, neuropathic or nociplastic – in patients with low back pain.

This calls on clinicians to consider the duration and distribution of low back pain, whether the pain is mainly caused by nociceptive or neuropathic mechanisms, pain hypersensitivity, and any comorbidities.

“The seven steps in the figure do not align with routine clinical care, but clinicians are advised to collect all information as they normally would and check the seven steps after,” the authors advised.

The expert group also developed a set of potential recommendations for low back pain management depending on pain phenotype.

For example, where pain is predominantly nociceptive, “treatment could plausibly be expected to be effective if it targets what is driving the nociceptive input.

“This implies that the first line treatment should target that nociceptive driver and this could include conservative interventions such as activity modifications (e.g., pacing periods of standing and walking), limited oral medications or topical treatment, physical therapy, lifestyle modifications, and selected, evidence-based intervention techniques,” they said.

Surgery can be considered in patients whose pain is not improved through “conservative management”, while pharmacological treatment should comprise short-term non-opioid analgesics such as NSAIDs and COX-2 inhibitors, depending on whether the nociceptive input is inflammatory or not, according to the paper.

“Opioids can be considered for predominant nociceptive low back pain only if established non-pharmacological treatments and established non-opioid analgesics are not effective, not tolerated, contraindicated, or not available,” the authors stressed.

Clinical management of predominant neuropathic and nociplastic low back pain is “substantially different” from that of predominant nociceptive low back pain, the experts noted.

Mangement according to pain phenotype 

They stressed that treatment should be tailored to the type of neuropathy driving the pain. “For instance, superior and middle cluneal nerve entrapment neuropathy can potentially benefit from a nerve block and neurolysis, whereas surgery for lumbar radiculopathy has high success rates (75-80%) and consequently can be considered when multimodal conservative treatment did not improve pain or function and if imaging findings match the clinical presentation,” they advised.

Antidepressants can be considered as a treatment for predominant neuropathic low back pain, but the evidence does not back the use of anticonvulsants such as gabapentin. Of note, opioids are only a third-line choice for neuropathic pain, as there is weak evidence of their efficacy.

Non-pharmacological approaches, such as psychological therapies and pain neuroscience education, should be prioritised for management of predominant nociplastic low back pain, as most medications “provide only modest benefits”, the authors noted.

Also, surgery “is unlikely to be indicated for treating predominant nociplastic low back pain, and the use of opioid analgesics is strongly discouraged,” they stressed.

There was strong consensus among the BACPAP consortium for each of the recommendations on pain phenotyping and management recommendations.

However, “before implementation, studies examining the classification accuracy, predictive ability, and efficacy of personalised treatments when following the BACPAP consortium’s consensus recommendations are needed.

“Therefore, these recommendations are not ready to be implemented in clinical practice until additional evidence is generated that is specific to these low back pain phenotypes,” the group stressed.

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