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• This was a multicentre (n=4), prospective study to examine the outcomes of treating intractable low back pain with SCS using paddle electrodes and a radio frequency stimulator in 60 patients at, or up to 2 years post implantation.
  
  
• At the time of publication, 44 patients had undergone implantation and follow-up data were available for 41 patients.
  
  
• Following an extended trial stimulation period (minimum 3 days), patients who met the inclusion criteria were implanted with either one 16-electrode paddle lead or two 8-electrode paddle leads (both from Advanced Neuromodulation Systems).
  
  
• Patients completed pre-operative questionnaires and outcome measurements included VAS, Oswestry Disability Questionnaire, Sickness Impact Profile (SIP) and patient satisfaction rating scale. Data were collected at approximately 6 months, 12 months and 24 months after implantation.
  
  
• Pre-operatively all patients had pain in both their back and legs, with more than 50% of their pain in their low back.

• The majority of patients reported fair to excellent pain relief in both the low back and legs:
  
  • At 6 months, 91.6% of patients reported fair to excellent relief in the legs and 82.7% reported fair to excellent relief in the low back.
    
  • At 1 year, 88.2% of patients reported fair to excellent relief in the legs and 68.8% reported fair to excellent relief in the low back.
    
    
• Significant improvement in function and QoL was found at both the 6 month and 1 year follow-ups using the Oswestry and SIP, respectively.
  
  
• The majority of patients reported that the procedure was worthwhile (92% at 6 months and 88% at 1 year). No patient indicated that the procedure was not worthwhile.

• The investigators concluded that SCS proved beneficial at one year for the treatment of patients with chronic low back and leg pain.
  
  
• The study endorsed the authors' experience that paddle electrodes seem to have an advantage over catheter-type electrodes in the long-term implementation of SCS.
  
  
• Several retrospective studies have reported on the success of SCS therapy in the treatment of chronic low back and leg pain. To date, this study and the study conducted by Burchiel are the only prospective studies in this indication.

• Many studies have demonstrated the efficacy of SCS in relieving pain, but there has been less focus on the post-implantation requirements of patients in the long term.
  
  
• This study evaluated experience with SCS over a 13-year period with emphasis on surgical complications, revisions and pain relief.
  
  
• The study population comprised 70 patients with severe, chronic pain refractory to conventional treatment (minimum duration 5 years) who underwent SCS implantation during the 1980s and 1990s. The most common indication (51% of patients) was Failed Back Surgery Syndrome (FBSS).
  
  
• Most patients received Itrel 3.
  
  
• The evaluation took the form of a retrospective study of medical/surgical records and a patient questionnaire.

• Sixty percent of patients reported substantial relief of pain.
  
  
• A total of 72 surgical revisions were performed during the follow-up period for a variety of reasons: electrode replacement/repositioning (32), generator replacement (22), cable failure (6) and implant removal (12). Six implants (8.6%) became infected, 3 were removed and the remainder treated with antibiotics.
  
  
• Twenty-eight (40%) of the implants required no revision during the follow-up period.
  
  
• The median time from implantation to revision was 3 years.

• The principal finding of the study was that the majority of patients (60%) with severe chronic pain refractory to all previous treatment who undergo SCS derive significant benefit in terms of pain relief. Clinicians reported substantial pain relief in 67% of patients, despite the fact that the entry criteria stipulated that pain duration had to be at least 5 years or more.
  
  
• Although no patients suffered major complications after implantation of a SCS device, the majority of patients require one or more surgical revisions for a variety of technical and biological reasons.
  
  
• Optimum utility of these devices requires a dedicated team experienced in patient assessment and aftercare.

• At follow-up:
  • 60% of patients thought their pain had improved
  • 78% would recommend SCS to others with similar problems
  • 69% were satisfied with the treatment
  • 75% would have the procedure done again if they had known the outcome before the operation
    
    
• Among the 36 patients in whom the SCS system was implanted, it was later removed in 4 patients due to lack of sufficient pain relief.
  

• Significant technological advances in stimulator design have broadened the indications for SCS.
  
  
• In this retrospective study, the majority of patients with chronic, intractable axial low back pain were satisfied with the results of SCS with dual leads and knowing the outcome would be prepared to undergo the procedure again.
  
  
• These results suggest that further investigation of SCS is warranted in this difficult-to-treat patient population.
  
  
• Note: This is one of the best studies that can be used to demonstrate that SCS and dual leads work in the most difficult FBSS patient population: those with predominant axial low back pain (90% of these needed two leads for adequate pain relief).
  

• The aim of this study was to evaluate the efficacy of an implanted SCS system in terms of pain relief and quality of life and to assess the accuracy of patient selection criteria.
  
  
• 123 patients who had had a SCS device in place for a period of 10 years took part in the study. This represented 125 pain cases, as two patients had double implants.
  
  
• The most common indication (78.4% of patients) was pain from 'Failed Back Surgery Syndrome' (FBSS).
  
  
• Patients underwent an interview with an independent physician and completed a questionnaire. The efficacy of SCS was evaluated on the basis of degree of pain relief, change in quality of life and changes in pain medication.
  
  
• The study population consisted of patients who met defined selection criteria for SCS. In accordance with Belgium law, patients had undergone a 4 week trial stimulation period prior to implantation.
  
  
• Most patients received Itrel 3.
  

• ·The study confirmed the efficacy of SCS for a well-selected patient population; 68% of patients assessed the outcome of SCS as excellent to good at long-term follow-up (average almost 4 years).
  
  
• In patients without back pain, there was a 50% improvement in leg pain on an average day.
  
  
• The patients with back pain had 54% less back pain and 64% less leg pain on an average day.
  
  
• Median intake of pain medication reduced from 3-4 intakes a day prior to treatment to 1-2 per day after SCS, corresponding to a 50% improvement.
  
  
• Patients reported statistically significant improvements in quality of life parameters and sleep disturbances with SCS.
  

• This independent evaluation demonstrates that SCS is a valuable and effective treatment for the management of patients with certain types of chronic pain intractable to other therapies.
  
  
• The study confirms the accuracy of the selection criteria and the relatively long trial stimulation period presumably excludes some of the placebo responders.
  
  
• One possible explanation for the high success rate of SCS in this study was the large volume of patients and extensive experience of SCS treatment associated with the study center.
  

• The aim of this pilot clinical study was to evaluate a new dual lead spinal cord stimulation (SCS) system, consisting of a new Medtronic Mattrix stimulator, as a treatment for the pain associated with failed back surgery syndrome (FBSS).
  
  
• The study population consisted of 20, non-randomised patients, each with a long history of chronic lower back and leg pain associated with FBSS, which was unresponsive to non-invasive therapies. Each patient received a dual lead SCS system implant, following a successful trial period.
  
  
• Information on a range of parameters, including VAS (visual analogue scale) pain ratings and medication use, was retrospectively sought from each patient after the implants were in place, and at a 2 year follow up.
  

• Overall, the dual lead SCS system provided an average paraesthesia coverage of 86.5% (range 70 - 100%).
  
  
• At the final follow up, patients reported having less pain and using fewer analgesics compared to their pre-implant experience, these improvements being statistically significant. Patients also felt that they were sleeping better and their ability to participate in social activities had increased.
  
  
• When asked if they would have a dual lead system implanted again, 65% of patients originally sought for study participation indicated that they would.

• In this retrospective pilot study, dual lead stimulation proves beneficial for patients with chronic low back pain and leg pain associated with FBSS. Considering lower back pain remains largely unresponsive to single lead stimulation therapy, this result is encouraging.
  
  
• Based upon the results of this study, patients receiving dual lead SCS can expect to have less pain, use fewer analgesics, sleep better and increase their ability to participate in social activities. Further clinical studies are required to confirm these preliminary findings.

• The aim of this study was to identify psychological factors associated with a positive response to spinal cord stimulation (SCS).
  
  
• The study population consisted of 43 patients with chronic pain who had been referred for possible SCS. Of these, 72% had failed back surgery syndrome.
  
  
• Following a detailed psychological evaluation, patients underwent a 3-day trial of SCS with Pisces-Quadripolar electrodes; in a few cases laminectomy was performed and a Resume electrode implanted.
  
  
• Patients were retrospectively assigned to two groups according to the outcome of the trial. 'Success' was defined as at least 50% pain relief, and 'failure' as less than 50% pain relief.

• Of the 40 patients who completed the psychological evaluation, 58% reported at least 50% pain relief.
  
  
• Compared with the patients in whom treatment was considered to have failed, these patients showed significantly lower scores for depression (P=0.007) and higher scores for mania (P=0.025) in the Minnesota Multiphasic Personality Profile.

• There is widespread acceptance that psychological evaluation is a necessary part of patient selection for SCS. However, no specific psychological markers that correlate with successful pain relief have been clearly defined.
  
  
• The results of this study suggest that the patient's mood is an important predictor of trial outcome. Successful trials are associated with patients who are less depressed and have higher energy levels preoperatively.

• The aim of this study was to determine the value of specific prognostic parameters in the prediction of successful SCS.
  
  
• A total of 235 patients with an average age of 51.4 years were included in the study. All patients had chronic intractable pain of various aetiologies, including failed back syndrome, peripheral vascular disease and peripheral neuropathy. All patients had used narcotic medication and were found to be refractory to conservative modalities of pain relief.
  
  
• Following a successful trial period using Pisces-Sigma or later in the study Pisces-Quadripolar electrodes implanted percutaneously or Resume electrodes, 189 patients received a permanent, multipolar Medtronic Itrel I, Itrel II, or X-trel system. Subjective pain assessments were conducted at 6-monthly intervals, with a mean follow-up period of 66 months.

• Multipolar, Medtronic Itrel I, Itrel II, or X-trel system implants provide satisfactory relief from chronic pain of various aetiologies, regardless of patient age or sex, and significantly increase patients' activities of daily living.
  
  
• The most responsive syndromes to SCS include failed back syndrome, reflex sympathetic dystrophy and peripheral vascular disease.
  
  
• Patients with fewer previous surgeries and a shorter duration of time between surgeries and SCS implantation had a more favourable response to SCS.
  
  
• Possible prognostic factors for successful SCS include: (i) the aetiology of the pain syndrome; (ii) the number of previous surgical procedures; and (iii) the duration of time between surgical interventions and SCS implantation.

• Prospective, randomised comparison of reoperation and spinal cord stimulation (SCS) in patients with persistent radicular pain following lumbosacral spine surgery.
  
  
• After 6 months, patients whose initial treatment had failed were allowed to switch to the other one.

• There is a clinical advantage for SCS over reoperation in failed back surgery syndrome (FBSS).
  
  
• SCS was also a cost-effective alternative to reoperation in selected patients with FBSS.
  
  
• The judicious use of SCS early in the treatment of FBSS should reduce direct medical costs, as well as treating chronic pain effectively.
  

• The preliminary results from this study indicate that 1-year of SCS can result in significant improvements in pain and quality-of-life among patients with chronic back and extremity pain.
  
  
• In conjunction with a low complication rate, this study indicates that SCS is a relatively safe and effective approach to long-term pain management.

• The results of this study indicate that SCS can: (i) provide pain relief; (ii) significantly improve function, and (iii) reduce or eliminate the need for narcotic medication in chronic, failed spine surgery patients who are not helped by conservative therapy and who are not candidates for more conventional surgical treatments.
  
  
• The benefits provided by SCS were maintained over a 24 month period, indicating the long-term effectiveness of this treatment.
  
  
• Considering that none of the Medtronic devices used in this study failed, SCS represents a highly reliable and effective technique for the treatment of chronic, lower extremity pain.

• The results of this study suggest that patient age, depression and MPQe may be clinically useful in predicting the outcome of SCS. Older and more depressed patients are less likely to report adequate pain relief, whereas those who consider their overall pain experience to be more intense (high MPQe) are more likely to report a greater improvement in pain.
  
  
• It should be noted, however, that variables other than those investigated in this study may be important predictors of response in a larger patient population.
  

• The Interim results from this study show a significant advantage for SCS over reoperation for the treatment of FBSS, using the primary outcome measure of crossover frequency.
  
  
• Further outcome measures need to be assessed when the full study population is available for long-term follow up. These include medication use, work status, activities of daily living and health care cost data.
  
  
• Preliminary results indicate that SCS may provide an effective alternative to reoperation in patients with FBSS.
  
  

• Technical improvements in spinal cord stimulation have led to enhanced system reliability and improved clinical outcome.
  
  
• Since a majority of patients continued to report at least 50% pain relief at an average time of 7 years after implantation, spinal cord stimulation compares favourably with other treatment modalities for chronic, intractable, pain.
  

• In this retrospective review, failed back surgery syndrome (FBSS) was defined as recurrent or persistent pain after at least one previous lumbosacral operation. Repeated lumbosacral operations were 'successful' in only one third of patients. This suggests that many patients experienced worsening despite, or because of, surgery.
  
  
• Selection criteria for repeated surgery should be further refined, and alternative treatments for FBSS should be investigated prospectively.
  

• These results, in patients without surgically treatable lesions, compare favourably with those in previous series of patients with FBSS who underwent either reoperation for diagnosed surgical lesions or ganglionectomy for monoradicular pain syndromes.