3 The technology
3.1 Spinal cord stimulation (SCS) is a treatment for chronic pain that is usually considered after standard treatments (such as those listed in section 2.4) have failed. SCS modifies the perception of neuropathic and ischaemic pain by stimulating the dorsal column of the spinal cord. SCS is minimally invasive and reversible. A typical SCS system has four components.
A neurostimulator that generates an electrical pulse (or receives radio frequency pulses) – this is surgically implanted under the skin in the abdomen or in the buttock area.
An electrode(s) implanted near the spinal cord either surgically or percutaneously (the latter via puncture, rather than through an open surgical incision, of the skin).
A lead that connects the electrode(s) to the neurostimulator.
A remote controller that is used to turn the neurostimulator on or off and to adjust the level of stimulation.
3.2 Neurostimulators may be either implantable pulse generators (IPGs), which use either a non-rechargeable or a rechargeable internal battery, or radio frequency devices, which receive energy in the form of radio frequency pulses from an external device powered by a rechargeable battery. Devices are not specific to pain conditions. However, SCS systems will have different longevities dependant on a person's pain patterns, stimulation power required and body area involved. Therefore the choice of SCS system will depend on these factors as well as preferences of the individual person and the clinician.
3.3 Fourteen SCS devices manufactured by three companies have received European approval to market (CE marking) and are available in the UK. List prices for SCS systems are not publicly available, but the Association of British Healthcare Industries (ABHI) provided indicative SCS equipment costs: a mid-range price based on the average cost of each manufacturer's best-selling product, a lower cost based on the average cost of each manufacturer's least expensive product, and an upper cost based on the average cost of the most expensive product. The prices supplied were: SCS system including neurostimulator, controller and charger, if applicable, but excluding leads £9282 (range £6858 to £13,289); and leads £1544 (range £928 to £1804) or £1136 (range £1065 to £1158) for surgical or percutaneous implantation, respectively. Device and component prices may vary in different settings because of negotiated procurement discounts.
3.4 Boston Scientific manufactures a rechargeable IPG (Precision SC-1110). The device is CE marked as an aid in the management of chronic intractable pain.
3.5 Advanced Neuromodulation Systems manufactures seven devices. Four are non-rechargeable IPGs (Genesis IPG 3608, Genesis XP 3609, Genesis XP Dual 3644 and Genesis G4), one is a rechargeable IPG (Eon), and two are radio frequency systems consisting of an implant with external rechargeable power (Renew 3408 and Renew 3416). The devices are CE marked as aids in the management of chronic intractable pain of the trunk and/or limbs.
3.6 Medtronic manufactures six devices. Four are non-rechargeable IPGs (Synergy, Synergy Versitrel, Itrel 3 and Prime ADVANCED) and two are rechargeable IPGs (Restore ADVANCED and Restore ULTRA). The devices are CE marked as aids in the management of chronic intractable pain of the trunk and/or limbs, peripheral vascular disease, or refractory angina pectoris.
3.7 Further details of contraindications, implant requirements and potential complications can be found in the implant manual for each SCS component.
3.8 For FBSS, the British Pain Society (BPS) suggests that SCS may be an alternative to a repeat operation or increased opioid use. For CRPS, the BPS suggests that SCS may be considered after pharmacotherapy and nerve blocks have been tried but have not provided adequate pain relief. It is acknowledged that SCS is not suitable for everyone with chronic pain, and that it should be used only as part of a multidisciplinary team approach with other therapies and a strategy for rehabilitation. Re-intervention may be necessary to replace the SCS device because of complications (component failures, lead position or implant-related adverse events such as infection) or when the power source is depleted. Ongoing care of patients is also required, which includes 24-hour availability for the investigation and management of potentially serious problems.
3.9 People selected for SCS normally have a stimulation trial to determine suitability for permanent implantation of a neurostimulator. This usually involves implanting the electrode(s) and leads with a temporary external device, which is used to mimic the effects of an implanted neurostimulator. A stimulation trial will assess tolerability (for example, of the stimulation sensation or the stimulation device) and the degree of pain relief likely to be achieved with full implantation.