Spinal Cord Stimulators in Neuropathic Pain
Introduction Chronic pain is very common Immense physical, psychological, societal impact Financial burden
Neuropathic pain Damage or dysfunction of the nervous system Typical symptoms - burning - shooting - allodynia - hyperalgesia
Case history (1) Mr X - Referred to the pain clinic PC - Right arm pain Hx PC - Day 1 post medical procedure - Tingling, weakness, numbness of right arm
Case history (1) Investigations - MRI - Nerve conduction studies - Electromyography Diagnosis - Brachial plexus injury Conservative management strategy EMG
Case history (1) Follow up at 6 weeks - Burning, painful to touch, skin discolouration Diagnosis - Complex regional pain syndrome (CRPS) Therapies in pain clinic - Neurogenic pain medications - Cervical sympathetic block
Case history (1) SCS inserted 2013
Case history (2) Mr FF, 62 yrs - GP referral to pain clinic PC - Back pain radiating to both legs Hx PC - 20 year history of back pain - Physiotherapy/analgesia - Multiple surgical procedures
Case history (2) Diagnosis - “Failed back surgery syndrome” Therapies in pain clinic - Neurogenic pain medications - Epidural and facet joint injections - L5/S1 nerve root block
Case history (2) SCS inserted 2013
Management of chronic pain
Neuromodulation Therapeutic alteration of the nervous system Electrical or pharmacological Implanted devices
Gate control theory of pain
Gate control theory and spinal cord stimulators
History of spinal cords stimulators
Which patients might be suitable for a SCS? Failed back surgery syndrome CRPS Peripheral neuropathy Ischaemic limb pain Angina
SCS electrodes
Components of the SCS
Phases of SCS implantation 1. Assessment phase - appropriate pathology - appropriate patient 2. Trial phase 3. Implantation phase
Where are the electrodes placed? Upper extremity T1-T2 Low back T8-T10 Lower extremity T10-T12
Trial phase
What are the criteria for a successful trial? 50% pain Area of parasthesia = area of pain Parasthesia not unpleasant Functional improvement
Complications of SCS Additional revision of the device (23%) Hardware malfunction (10%) Infection (4.6%) Complications during insertion
Some issues for patients….
NICE Guidelines
Case history (1) Complex regional pain syndrome 4 months later VAS scores 10 3 Some restoration of hand function Reduction in analgesic medication Improved mood
Case history (2) Failed back surgery syndrome 2 months later VAS scores 10 2 Improved mobility Reduced analgesic medications Improved mood
Conclusion Neuropathic pain is common, some patients are refractory to standard therapies Neuromodulation is an alternative method for treating severe, intractable pain Excellent results can be achieved with selected patients
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