PROCESS trial shows addition of SCS gives best results for FBSS

PROCESS (prospective randomised controlled multi-centre study) is the first randomised-control trial to evaluate the cost-effectiveness of spinal cord stimulation (SCS) as a treatment therapy for chronic neuropathic pain in patients suffering from failed back surgery syndrome (FBSS). It was recently completed and the results have been published in the journal Pain. PROCESS prospectively analysed all health service resource consumption costs as well as assessing benefits in terms of improvements in quality of life.1,2 It showed that SCS therapy significantly enhances pain relief and improves quality of life in patients with FBSS who also suffer from chronic neuropathic back and leg pain.1

Chronic neuropathic pain is most commonly located in the back and legs. Of those patients who undergo lumbosacral spine surgery to alleviate neuropathic radicular pain, 10-40% develop persistent or recurrent pain – a condition known as FBSS.² Neuropathic pain secondary to FBSS leads to persistent back and leg pain, disability, and a substantial reduction in quality of life. The healthcare costs associated with neuropathic pain are considerably high.²

"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.

SCS has shown remarkable success in alleviating refractory neuropathic pain associated with FBSS. However, it is an expensive technology.³ Until now, no study has investigated in detail the ‘real life’ cost effectiveness of SCS in the treatment of neuropathic pain resulting from FBSS by considering the use of healthcare resources, including hospitalisation, cost of devices and drugs and, importantly, quality of life. The PROCESS trial has done just this.

The PROCESS trial recruited 100 patients suffering neuropathic radicular pain in the legs with a documented history of nerve injury from 12 centres across Europe, Australia, Israel and Canada. Patients admitted into the trial had a pain intensity that was at least 50mm (according to the VAS pain scale) for a minimum of 6 months after surgery for a herniated disc.² Patients were randomised to receive either non-surgical conventional medical management (CMM) alone, or CMM together with SCS. CMM included oral medication, nerve blocks, epidural corticosteroids, psychological therapy, physical rehabilitative therapy and chiropractic care.² Patients were assessed at baseline and at three and six months. Costs and outcomes were determined six months after beginning the trial.²

The primary outcome measure of the study was 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.² 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.²

Patients in the SCS group experienced significant improvement in pain relief and improved health related quality of life (HRQoL) as measured by the SF-36 (Short form 36) and EuroQoL (EQ-5D) scale, as well as improved functional capacity and treatment satisfaction.² In addition, drugs such as opioids, NSAIDS, anti-depressants and anticonvulsants were utilised much less in the SCS group compared with the CMM group.² There was also a reduction in health care resource use for non-drug therapy, such as massage and physical therapy for pain, in the SCS group. A reduced proportion of patients in the SCS group required contact with health-care professionals. The SCS group experienced fewer complications, which also minimised healthcare resource use. In comparison, the CMM group experienced little pain relief or other beneficial outcomes.^1,2

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.¹

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 authors emphasise that there is significant cost-saving in terms of CMM-related and non-SCS related events. 15% of the total mean additional cost is offset in the six months from 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, in the long term, SCS may be cost-saving.¹

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.¹

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. 

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

Professor Buchser said categorically, that doctors should consider adding SCS to the treatment programme. 

The composition of CMM care in the trial were at the control of physicians, mirroring clinical practice and thus allowing greater generalisation of results.¹ The only drawback was the inability to blind the participants, due to the nature of the implant that produces paraesthesia. Therefore this study is unable to exclude a placebo effect.¹

Another difficulty, according to Dr O’Callaghan, is the cost involved in this type of study, and the need therefore for the company to contribute to the cost.

"This always throws a question mark over the study outcome, however I believe that health professionals must look at the quality of the research and the results coming out of the research and make up their own mind," said Dr O’Callaghan. 

Although the study could not be carried on beyond six months for ethical reasons, the benefits were sustained in a subgroup of patients who continued to used the stimulator on a long-term basis.¹

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, HRQoL and functional capacity of FBSS patients with chronic neuropathic back and leg pain.¹

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, because of its invasive nature I still have some hesitation in doing this and therefore I can understand why other doctors who are less experienced with spinal cord stimulation would have even more hesitation," said Dr O’Callaghan. "This may be something that we 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.