Adding spinal cord stimulation to treatment plan gives best results for FBSS pain

Results of the PROCESS (prospective randomised controlled multi-centre study) trial were recently published in the journal Pain. They showed that spinal cord stimulation (SCS) therapy significantly enhances pain relief and improves quality of life in patients with failed back surgery syndrome (FBSS) who also suffer from chronic neuropathic back and leg pain.

Around 10-40% of patients who undergo lumbosacral spine surgery to alleviate neuropathic radicular pain develop persistent or recurrent pain – a condition known as failed back surgery syndrome (FBSS).

Neuropathic pain secondary to FBSS leads to persistent back and leg pain, disability and a substantial reduction in quality of life in sufferers of this condition. The healthcare costs associated with neuropathic pain are considerably high.

Spinal cord stimulation has shown remarkable success in alleviating neuropathic pain associated with FBSS. However, it is an expensive technology. The clinical effectiveness and other benefits of SCS need to be weighed up against the costs and effect on quality of life.

"A patient with a spinal cord stimulator is likely to have a significantly better quality of life than a patient with similar type pain who has conventional medical management"  said Dr Jim O’Callaghan, Australian investigator on the PROCESS trial and pain specialist at Axxon Pain Medicine in Brisbane.

The PROCESS trial is the first randomised-control trial to investigate in detail the ‘real life’ cost-effectiveness of SCS as a treatment therapy for chronic neuropathic pain in patients suffering from FBSS by prospectively analysing all health service resource consumption costs, including hospitalisation and cost of devices and drugs, as well as assessing benefits in terms of improvements in quality of life.

The PROCESS trial recruited 100 patients from 12 centres across Europe, Australia, Israel and Canada. The patients suffered neuropathic pain of radicular origin in the legs, and had a documented history of nerve injury. Patients admitted into the trial had a pain intensity that was at least 50mm on a visual analog pain scale (VAS) and lasted for more than 6 months after surgery for a herniated disc (a VAS requires patients to rate their pain from none to very severe along a 100mm long line). Patients were randomised to receive either non-surgical conventional medical management (CMM) alone, or CMM with SCS. CMM included oral medication, nerve blocks, epidural corticosteroids, psychological therapy, physical rehabilitative therapy and chiropractic care. Patients were assessed at the start of the trial, at three and at six months. Costs and outcomes were determined after the first six months.

One of the main aims of the study was to determine the proportion of patients to achieve at least 50% leg pain relief. This was attained by 48% of the SCS group patients, compared to only 9% in the CMM group. Secondary outcomes included improvement in back or leg pain, functional capacity, health related quality of life, use of pain medication and non-drug pain treatment in addition to several other measures.

Patients in the SCS group experienced significant improvement in pain relief and improved health related quality of life as well as improved functional capacity and treatment satisfaction. In contrast, the CMM group experienced little pain relief or other beneficial outcomes. Drugs such as opioids, NSAIDS, anti-depressants and anticonvulsants were used much less in the SCS group compared with the CMM group. Health care resource use was reduced for non-drug therapies (e.g. massage and physical therapy for pain) in the SCS group, and fewer patients required contact with health-care professionals. The SCS group also experienced fewer complications, which further reduced health care resource use.

Dr O’Callaghan said, "In my mind there is no doubt about the fact that a patient with a spinal cord stimulator is likely to have a significantly better quality of life than the patient with similar type pain who has conventional medical management."

SCS proved to be more expensive due to the initial implant costs and associated hospital stay, with a total additional mean cost of £11,373 (AU$23,440) per patient. The average patient cost after the 6 month period was £15,081 in the SCS group and £3,573 in the CMM group.

Dr O’Callaghan said that after 6 months the patients in the conservative or conventional medical management group were allowed to cross over to spinal cord stimulation and vice versa. The groups were therefore no longer able to be compared.  

"Most patients will not agree to not having a treatment such as spinal cord stimulation when they know that it is available." 

This is the difficulty with a long term study comparing spinal cord stimulation to conventional medical management, said Dr O’Callaghan.

"Our group of patients in the PROCESS study were prepared to wait 6 months, but the feedback we got was that patients would not have been prepared to wait 2 years before crossing over if their pain was not well controlled with conventional medical management." 

The upfront cost of SCS is considerable. However, the trial authors emphasise that there is a significant cost saving in terms of CMM-related and non-SCS related events. 15% of the total additional mean cost is offset by the reduction in drugs and non-drug treatments. The cost of pain medication on average was £321 less in SCS patients. Non-drug therapy costs were £134 in SCS group, compared to £1835 for CMM patients. This suggests that SCS may be cost-saving in the long term.

The PROCESS trial is one of only a few studies to produce data which can be employed in economic analysis so that a ‘real life’ cost effectiveness can be determined, including detailed resource consumption information for hospitalisation, cost of services, drugs and pain management.

Dr O’Callaghan said that many studies have been carried out around the world on the cost effectiveness of spinal cord stimulation and the results are fairly consistent. By approximately 2 years the financial burden of SCS was equivalent to more conservative management, and at 5 years post-operatively SCS had a distinct cost effectiveness advantage over non-surgical management.

The difficulty therefore is the initial upfront cost of spinal cord stimulation versus the lower but ongoing costs of conventional medical management, said Dr O’Callaghan.

A researcher involved in the study, from the Department of Anaesthesia and Pain Management at the Hospital of Morges in Switzerland, Professor Eric Buchser said, as Australian cost structures and prices are similar to most advanced nations, the results of the PROCESS trial would be relevant for Australia.

The only drawback was that, due to the nature of the implant, researchers were unable to ‘blind’ the participants by keeping them ignorant of which treatment group they were in. Therefore this study was unable to exclude a placebo effect.

But Professor Bushser said that doctors should consider adding SCS to the treatment programme.

Although the study could not be carried on longer than six months for ethical reasons, the benefits were found to be sustained within a subgroup of patients who continued to use the stimulator on a long-term basis.

A 24 month follow-up study has been submitted, according to Professor Buchser.

The PROCESS trial demonstrated that the addition of SCS to CMM results in enhanced pain relief, health related quality of life and functional capacity of FBSS patients with chronic neuropathic back and leg pain.

The results have made Dr O’Callaghan reconsider where spinal cord stimulation should come into the management regime for patients with radicular neuropathic pain, he said.

"I believe it should be offered at an earlier stage, and to more patients."

However, said Dr O’Callaghan, the invasive nature of SCS means he is still hesitant about doing so, and therefore he can understand why other doctors would also hesitate. He said it may be something that can be overcome with time. 

These results provide patients and doctors with much to consider in deciding whether to use SCS as an added treatment option for neuropathic pain associated with FBSS. Although the costs are significantly higher with this technology, the improvement in quality of life may well be worth it.

References

1. Manca A,  Kumar K, Taylor RS, Jacques L, Eldabe S, Meglio M, et al. Quality of life, resource consumption and costs of spinal cord stimulation versus conventional medical management in neuropathic pain patients with failed back surgery syndrome (PROCESS trial). [online publication] European Journal of Pain 2008.
2. Kumar K, Taylor RS, Jacques L, Eldabe S, Meglio M, Molet J, et al. Spinal cord stimulation versus conventional medical management for neuropathic pain: A multicentre randomised controlled trial in patients with failed back surgery syndrome. Pain 2007; 132: 179-88.
3. Turner JA, Loeserc JD, Deyoe RA, Sandersf SB. Spinal cord stimulation for patients with failed back surgery syndrome or complex regional pain syndrome: a systematic review of effectiveness and complications. Pain 2004; 108: 137-47.