By Palanisamy Vijayanand
(A talk delivered for the Department of Neurology, CARE Hospital, Hyderabad)
Pain is a common symptom in many neurological conditions. Neuropathic pain caused due to damage or dysfunction of the peripheral or central somatosensory system could be distressing, and might add to other neurological symptoms such as weakness, tremors and dystonia. Moreover, patients with neurological conditions could have pain unrelated to their condition such as osteoarthritis or low back pain. Most neuropathic pains could be managed conservatively with a combination of medications and rehabilitation. Long-standing neuralgias, however, could cause peripheral as well as central sensitisation resulting in severe distressing pains which are refractory to medical management. This is compounded by the fact that the mechanisms of certain pain conditions such as trigeminal neuralgia are yet to be elucidated.
A multi-disciplinary management of pain involving allied health professionals such as psychologists, physiotherapists and occupational therapists is important. Equally essential is the precision diagnosis and management of pain using interventional pain management techniques. As ectopic activity could happen in any peripheral nerve, a test block of the nerve confirms the diagnosis. This could be followed up with either ablation or neuromodulation techniques. Interventions could, therefore, help in the treatment as well as the diagnosis of neuralgias. Radiofrequency ablation of the Gasserian ganglion for trigeminal neuralgia has shown beneficial effects in 90% of patients, for upto 3 years, when the pain is chiefly distributed along the maxillary and mandibular divisions. Similarly, atypical facial pains respond to spheno-palatine ganglion ablation. Neuralgias such as glosso-pharyngeal neuralgia and occipital neuralgia could, in addition, be diagnosed precisely and managed with interventional techniques.
Headaches originating from the cervical facet joints (cervicogenic headaches) could be diagnosed precisely by test blocking the medial branch of the posterior primary rami of the spinal nerves. This could then be followed up with radiofrequency ablation for prolonged benefits. Cervical epidurals provide relief in radicular arm pains as well as discogenic axial neck pain. Staying with the spine, lumbar radicular pains and discogenic axial low back pains respond well to transforaminal epidural injections, except in multi-level spinal stenosis. We have used advanced interventions such as intrathecal drug delivery system (baclofen pump) for painful spasms following spinal cord injury or cerebral spasticity, and spinal cord stimulators for complex regional pain syndromes and failed back surgery syndromes.
In summary, we would like to highlight the role interventions could play in the precision diagnosis and management of pain, which would add a new dimension to managing neuralgias from a neurology perspective.