Spinal Cord Stimulation Dr Andrew Crockett


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Lecture given to the West of Scotland Pain Group on Wednesday 25th November 2009 by Dr Andrew Crockett, Consultant in Anaesthesia and Pain Management.

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Spinal Cord Stimulation Dr Andrew Crockett

  1. 1. Spinal Cord Stimulator Service The New Look
  2. 2. Introduction <ul><li>New MDT </li></ul><ul><li>Nature and History </li></ul><ul><li>Components </li></ul><ul><li>Mechanisms </li></ul><ul><li>Indications </li></ul><ul><li>Procedure </li></ul><ul><li>Evidence </li></ul><ul><li>Outcomes </li></ul><ul><li>The Future and what I’ve learnt </li></ul>
  3. 3. Introducing The Team
  4. 4. The new kids on the block
  5. 5. History <ul><li>1965 Melzack and Wall </li></ul><ul><li>1967 Shealy </li></ul><ul><li>1970’s indiscriminate use poor follow up </li></ul><ul><li>Neuropathic pain response </li></ul><ul><li>EBM/cost effectiveness </li></ul>
  6. 6. Nature <ul><li>Electrical stimulation </li></ul><ul><li>Direct nerve/field </li></ul><ul><li>Nerve root </li></ul><ul><li>Dorsal column </li></ul><ul><li>Deep brain </li></ul><ul><li>Motor cortex </li></ul>
  7. 7. Components <ul><li>Electrode </li></ul><ul><li>Connections </li></ul><ul><li>Battery (IPG) external/internal </li></ul><ul><li>Handset </li></ul>
  8. 8. Mechanisms <ul><li>Neuropathic </li></ul><ul><li>Sympathetic </li></ul>
  9. 9. Mechanisms <ul><li>Gate theory </li></ul><ul><li>Spinal segmental inhibition (second order and interneurones)‏ </li></ul><ul><li>Supraspinal (via posterior columns)‏ </li></ul><ul><li>Suppressed hyperexcitability in dorsal horns </li></ul><ul><li>Biochemical increased GABA decreased excitatory glutamate and aspartate </li></ul><ul><li>Not blocked by naloxone </li></ul><ul><li>Adenosine dependent systems </li></ul><ul><li>Increased b-endorphins in CSF </li></ul>
  10. 10. Indications <ul><li>Neuropathic Pain not responding to conventional treatment </li></ul><ul><li>Non nociceptive </li></ul><ul><li>Intact dorsal column </li></ul>
  11. 11. Indications <ul><li>Peripheral neuropathic pain </li></ul><ul><li>FBSS/FNSS (70:30)‏ </li></ul><ul><li>CRPS </li></ul><ul><li>Refractory Angina </li></ul><ul><li>Critical limb ischaemia </li></ul><ul><li>Other </li></ul>
  12. 12. Procedure
  13. 13. Evidence FBSS <ul><li>North et al: Spinal cord Stimulation vs repeated Lumbosacral Spine surgery for chronic pain: A Randomised Controlled Trial. Neurosurgery 56:98-107, 2005 </li></ul><ul><li>50 patients randomised to SCS or reoperation 6month and 2 year f/u </li></ul><ul><li>45 followed up. SCS (9/19) more successful than reop (3/26) p<0.01 </li></ul><ul><li>Outcome measure: >50% VAS improvement and patient satisfaction </li></ul><ul><li>Intention to treat </li></ul><ul><li>More opioid use in post reoperation patients. </li></ul><ul><li>No difference in ADLs or return to work. </li></ul>
  14. 14. Evidence FBSS <ul><li>Kumar et al: Spinal cord stimulation vs conventional medical management for neuropathic pain: A multicentre randomised controlled trial in patients with failed back surgery syndrome, Pain 132 (2007) 179–188 </li></ul><ul><li>100 patients randomised to SCS plus CMM or CMM alone </li></ul><ul><li>Intention to treat at 6 months 24/50 SCS and 4/44 CMM met primary outcome </li></ul><ul><li>Primary outcome: >50% VAS improvement in leg pain, multiple secondary outcomes. </li></ul><ul><li>Crossover allowed at 6 months </li></ul><ul><li>SCS also improved QoL, functional capacity, Rx satisfaction. </li></ul>
  15. 15. Evidence: FBSS <ul><li>Two class 2 RCT’s </li></ul><ul><li>Pooled case series 3307 patients 62% response </li></ul>
  16. 16. Cost effectiveness: FBSS <ul><li>Manca et al 6 month mean total cost 5x higher SCS vs CMT, but hrQoL much improved. Mean EQ-5D diff 0.21 at 6 months </li></ul><ul><li>Kumar et al SCS US$24799 mean cost over 5 years vs US$33722 for CMM </li></ul><ul><li>Qol 27% improvement (SCS), 12% improvement (CMM)‏ </li></ul>
  17. 17. Cost effectiveness: FBSS <ul><li>North et al. </li></ul><ul><li>SCS more effective, less expensive than reoperation. </li></ul><ul><li>Systematic review concluded II-1 or II-2 with1B or 1C/strong recommendation for clinical use on a long term basis. </li></ul>
  18. 18. NICE-FBSS <ul><li>£10480 per QALY gained SCS/CMM vs CMM alone </li></ul><ul><li>£9219 per QALY gained SCS vs reoperation </li></ul>
  19. 19. Complication rate: FBSS <ul><li>43% overall one or more Cx </li></ul><ul><li>Lead problems 27% </li></ul><ul><li>Infections 6% </li></ul><ul><li>Extension cable 10% </li></ul><ul><li>Generator problems 6% </li></ul><ul><li>Other eg CSF leak 7% </li></ul><ul><li>No neurological complications </li></ul>
  20. 20. Evidence: CRPS I <ul><li>Kemler et al: Spinal Cord Stimulation in Patients with Chronic Reflex Sympathetic Dystrophy The New England Journal of Medicine Issue: Volume 343(9), 31 August 2000, pp 618-624 </li></ul><ul><li>54 patients 36 SCS plus PT, 18 PT alone in Type I CRPS>6 months </li></ul><ul><li>Assessed 6months/ 2 years/ 5 years </li></ul><ul><li>VAS 6 months (-2.4cm, 0.2cm), 2 years (-2.1cm, 0cm), 5 years (-1.7cm, -1.0cm)‏ </li></ul><ul><li>HRQoL change 6 months (6% vs 3%), 2 years (7% vs 12%)‏ </li></ul><ul><li>Subgroup analysis at 5 years VAS (-2.5 vs -1.0) if received treatment allocated with SCS </li></ul><ul><li>Pooled case series data (n=561) 67% responders. (CRPS I and II)‏ </li></ul>
  21. 21. NICE - CRPS 1 <ul><li>£16596 per QALY gained for SCS vs CMM </li></ul>
  22. 22. Refractory Angina <ul><li>Studies </li></ul><ul><li>Reviews </li></ul><ul><li>NICE guidance </li></ul>
  23. 23. Studies <ul><li>8 medium to high quality studies </li></ul><ul><li>Variable numbers (n=12- n=104) overall 331 pts. </li></ul><ul><li>Decrease in anginal attacks </li></ul><ul><li>Improved functional status </li></ul><ul><li>Improved QoL </li></ul><ul><li>No effect on mortality, but less mortality than CABG. </li></ul><ul><li>Complication rate 12% </li></ul>
  24. 24. Review <ul><li>Generally positive improvement in many outcomes. </li></ul><ul><li>ESBY study (104 pts) SCS vs CABG showed similar analgesia, mortality, QoL after 5 years. </li></ul><ul><li>CABG had better exercise capacity. </li></ul>
  25. 25. NICE on RA <ul><li>No study had demonstrated significant differences in pain outcomes. </li></ul><ul><li>SCS seen to be comparable to CABG and PCI for functional outcomes. </li></ul><ul><li>Benefits less certain than FBSS and CRPS </li></ul><ul><li>May be useful for subgroups, but only to be used in the context of clinical studies. </li></ul>
  26. 26. Chronic Limb Ischaemia <ul><li>Non reconstructable limb ischaemia </li></ul><ul><li>Cochrane review </li></ul><ul><li>NICE guidance </li></ul>
  27. 27. Cochrane CLI <ul><li>Generally looking at limb salvage. </li></ul><ul><li>6 studies with 450 patients </li></ul><ul><li>Pooled data limb salvage significantly higher in SCS at 1 year vs CMM. </li></ul><ul><li>Analgesia equal in both groups, higher use of opioids in CMM. </li></ul><ul><li>Risk of complications 17% (NNH=6)‏ </li></ul><ul><li>Average 2 year cost: EUR 36500 SCS, EUR 28600 CMM. </li></ul>
  28. 28. NICE on CLI <ul><li>Concluded no studies had shown statistically significant differences in outcomes SCS vs CMM </li></ul><ul><li>May be subgroups with low peripheral O2 tension that benefit from SCS </li></ul><ul><li>Insufficient evidence on survival, HRQoL and cost effectiveness. </li></ul><ul><li>More trials needed. </li></ul>
  29. 29. Case series evidence <ul><li>Diabetic peripheral neuropathy </li></ul><ul><li>CRPS II </li></ul><ul><li>Peripheral nerve injury </li></ul><ul><li>PHN </li></ul><ul><li>Brachial plexus injury (partial)‏ </li></ul><ul><li>Amputation </li></ul><ul><li>Partial spinal cord injury </li></ul>
  30. 30. Pooled Complication rate <ul><li>Overall 33% in CRPS studies, 43% in FBSS </li></ul><ul><li>Dysfunction of stimulating apparatus mainly </li></ul><ul><li>Medical complications mainly minor and treatable. </li></ul><ul><li>Rarely major neurological complication </li></ul>
  31. 31. <ul><li>Lead migration 13.2% </li></ul><ul><li>Lead breakage 9.1% </li></ul><ul><li>Infection rate 3.4% </li></ul><ul><li>Hardware malfunction 2.9% </li></ul><ul><li>Battery failure 1.6% </li></ul><ul><li>Unwanted stimulation 2.4% </li></ul>
  32. 32. Early Audit <ul><li>10 year audit </li></ul><ul><li>55% patients > 50% relief </li></ul>
  33. 33. Audit 2007 <ul><li>Nov 2006-Dec 2007 </li></ul><ul><li>12 implants (7 trials – 5 completed)‏ </li></ul><ul><li>6 FBSS, 1 Cauda equina, 3 RA, 1 CRPS, 1 periph. Neuropathy. </li></ul><ul><li>36% > 50% relief </li></ul><ul><li>Patient satisfaction 8/12 would undergo procedure again, 10/12 would recommend procedure. </li></ul>
  34. 34. Complications <ul><li>Infection 4 </li></ul><ul><li>Seroma 3 </li></ul><ul><li>Haematoma 1 </li></ul><ul><li>Dural puncture 2 </li></ul><ul><li>Lead movement 2 </li></ul><ul><li>Lead fracture 1 </li></ul><ul><li>Programmer failure 1 </li></ul>
  35. 35. Audit 2008 <ul><li>January 2008 – December 2008 </li></ul><ul><li>14 patients (15 implants) (5 trials, 2 completed)‏ </li></ul><ul><li>FBSS 6, Radiculopathy 4, Cauda equina 1, RA 2, peripheral neuropathy 1. </li></ul><ul><li>6/13 (46%) >50% pain relief </li></ul><ul><li>6/13 reduced analgesic usage </li></ul><ul><li>Activity: 5/13 increase, 3/13 no diff. 5/13 reduced </li></ul>
  36. 36. <ul><li>Patient satisfaction 10/13 would undergo again, 2/13 would not, 11 would recommend to others 1 would not. </li></ul>
  37. 37. Complications <ul><li>Reaction to implant antibiotic 1 </li></ul><ul><li>Significant movement artefact 1 </li></ul><ul><li>Lead movement 1 </li></ul><ul><li>System damage 1 </li></ul>
  38. 38. Revisions <ul><li>Explantation 1 </li></ul><ul><li>Exploration 1 </li></ul><ul><li>Lead repostioned 1 </li></ul><ul><li>Failed revision 1 </li></ul>
  39. 39. MDT <ul><li>Data on 37 new patients assessed jointly by psychol/physio. </li></ul><ul><li>6 straight to trial </li></ul><ul><li>9 not suitable </li></ul><ul><li>4 referred back for individ. Physio/psychol. </li></ul><ul><li>18 individ physio/psychol Rx (14 went on to trial SCS)‏ </li></ul>
  40. 40. MDT assessment <ul><li>Assessment 1.5 hrs HAD TSK ODI </li></ul><ul><li>Individual work up </li></ul><ul><li>Trials </li></ul><ul><li>Post implant physio review 6 weeks </li></ul><ul><li>Long term F/U </li></ul><ul><li>Resources: 3 physio sessions, 2 psychology. </li></ul>
  41. 41. Guidelines <ul><li>BPS </li></ul><ul><li>NICE </li></ul><ul><li>EFNS </li></ul>
  42. 42. Glasgow set up <ul><li>Referral (GG&C and outside)‏ </li></ul><ul><li>Triage </li></ul><ul><li>Assessment </li></ul><ul><li>MDT discussion </li></ul><ul><li>Funding approval </li></ul><ul><li>Trial </li></ul><ul><li>Completion </li></ul><ul><li>Follow up </li></ul>
  43. 43. The what I’ve learnt bit! <ul><li>MDT and patient complexity </li></ul><ul><li>How enjoyable it is to work in a fully integrated MDT setting. </li></ul><ul><li>Facing your fears, how hard surgery is! </li></ul><ul><li>Some interventions do work. </li></ul><ul><li>A good result is not always a good result…the orthopaedic paradigm. </li></ul><ul><li>How to say no in the face of political pressure </li></ul><ul><li>How much we owe to Pete, Gavin, Anne and Alison. </li></ul>
  44. 44. Questions?