The Role of Rechargeable Systems in Neuromodulation
Table 2: Mean Annual Costs for Patients with Chronic Pain With Spinal Cord Stimulation Implanted
Type of Service Doctor’s office visit Accident and emergency
department visit Medical hospitalisation Nerve block injection Surgery
Magnetic resonance 192
4,248 306
8,689 472
imaging scan Computed tomography scan 294 Medication
Rehabilitation Total mean annual cost Source: Hornberger, et al., 2008.7
better tolerated or preferred; however, rechargeable devices certainly performed as well as non-rechargeable systems. In addition, a case study reported that four patients were very satisfied with the quality of stimulation provided by the rechargeable Restore neurostimulation system and noted a significant improvement in quality of life.12
Another advantage of rechargeable devices is that more power can be delivered, since frequent recharging can replace the energy in the system. For example, PW programming ranges of rechargeable implantable pulse generators now match those of RF systems, with programmability up to 1,000 μs.4
Furthermore, much more complex
systems have been developed that have multiple channels (independent programming of individual contacts allowing for steerable electrical fields) and constant current systems as well as constant voltage.3
These features can accommodate changing
electrode–tissue impedance over time. In several small clinical trials, this contact impedance has been shown to be highly variable and can reduce the efficacy of neurostimulation but complex electrode systems were shown to be a means of mitigating the problem.13–16
Some of these more complex
applications can be delivered from non-rechargeable battery powered devices; however, the development of these technologies has resulted from a freedom to design systems that are not restricted in power output. An additional benefit of rechargeable systems is that they can be made much smaller than their non-rechargeable equivalents.
Cost-effectiveness of Rechargeable versus Non-rechargeable Neuromodulation Devices The rechargeable systems have a higher initial set-up cost compared with their non-rechargeable equivalents. However, one study that investigated the average difference in lifetime costs between rechargeable and non-rechargeable IPGs used in SCS for failed back surgery syndrome (FBSS) showed that a rechargeable SCS system is projected to require between 2.6 and 4.2 fewer pulse generator replacements for battery depletion than a non-rechargeable SCS system.7
The study also showed that although
rechargeable systems are currently more expensive than non-rechargeable systems, these costs can be offset 4.1 years after implantation (see Figure 1).7
non-rechargeable system for an average 34.2
Furthermore, the total lifetime cost of a years, including
implantation, complication, removal and follow-up costs was EUROPEAN NEUROLOGICAL REVIEW
Recently, the National Institute for Health and Clinical Excellence (NICE), the advisory body in the UK, has published a health technology assessment for SCS which modelled the costs of treatment, including the need for battery replacement.17
The report showed that SCS was effective in reducing the chronic neuropathic 189
Figure 1: Cumulative Costs of Spinal Cord Stimulation System from Time of First Implantation, Rechargeable versus Non-rechargeable
$350,000 $300,000 $250,000 $200,000 $150,000 $100,000 $50,000
$0 0
$40,000 $80,000 $120,000
$0 02 4 Non-rechargeable Source: Hornberger, et al., 2008.7
estimated to be US$404,666 (2006 prices) compared with US$254,369 for a rechargeable system, giving a saving of US$150,297.7
6 8
Time since first implantation, years
Rechargeable 5 10 15 Time since first implantation, years
Rechargeable: 25-year battery life
Rechargeable: 10-year battery life
4.1 years Non-rechargeable 20
9.1 0.4
462 67
After Spinal Cord Stimulation Removed
Cost Per Unit of Service, US$ Number of Service Units Total Cost, US$ Number of Service Units 51
24.3 1.6
0.7 2.5 0
0.1 0.3
2,974 765 0
47 74
1,250 350
5,989 2.9
15.7 1.3 1.7
1
Total Cost, US$ 1,239 307
12,320 4,805
11,296 779
294
2,075 1,250
34,365
These
costs reflect estimations that patients with non-rechargeable systems will need 5.9 replacement procedures compared with 2.2 (range 1.7–3.3) for patients with rechargeable systems, that is, 3.7 fewer battery replacements over their lifetimes. The mean annual costs for patients with chronic pain for durations with implanted SCS devices and after removal are given in Table 2.
Cumulative costs Cumlulative costs
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